libbpf: BTF writer APIs #125
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Add APIs for appending new BTF types at the end of BTF object. Each BTF kind has either one API of the form btf__add_<kind>(). For types that have variable amount of additional items (struct/union, enum, func_proto, datasec), additional API is provided to emit each such item. E.g., for emitting a struct, one would use the following sequence of API calls: btf__add_struct(...); btf__add_field(...); ... btf__add_field(...); Each btf__add_field() will ensure that the last BTF type is of STRUCT or UNION kind and will automatically increment that type's vlen field. All the strings are provided as C strings (const char *), not a string offset. This significantly improves usability of BTF writer APIs. All such strings will be automatically appended to string section or existing string will be re-used, if such string was already added previously. Each API attempts to do all the reasonable validations, like enforcing non-empty names for entities with required names, proper value bounds, various bit offset restrictions, etc. Type ID validation is minimal because it's possible to emit a type that refers to type that will be emitted later, so libbpf has no way to enforce such cases. User must be careful to properly emit all the necessary types and specify type IDs that will be valid in the finally generated BTF. Each of btf__add_<kind>() APIs return new type ID on success or negative value on error. APIs like btf__add_field() that emit additional items return zero on success and negative value on error. Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
…_offset BTF strings are used not just for names, they can be arbitrary strings used for CO-RE relocations, line/func infos, etc. Thus "name_by_offset" terminology is too specific and might be misleading. Instead, introduce btf__str_by_offset() API which uses generic string terminology. Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Add selftests for BTF writer APIs. Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
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Master branch: 98b972d |
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At least one diff in series https://patchwork.ozlabs.org/project/netdev/list/?series=204718 irrelevant now. Closing PR. |
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Jan 19, 2022
…ed bind() Syzbot detected a NULL pointer dereference of nfc_llcp_sock->dev pointer (which is a 'struct nfc_dev *') with calls to llcp_sock_sendmsg() after a failed llcp_sock_bind(). The message being sent is a SOCK_DGRAM. KASAN report: BUG: KASAN: null-ptr-deref in nfc_alloc_send_skb+0x2d/0xc0 Read of size 4 at addr 00000000000005c8 by task llcp_sock_nfc_a/899 CPU: 5 PID: 899 Comm: llcp_sock_nfc_a Not tainted 5.16.0-rc6-next-20211224-00001-gc6437fbf18b0 #125 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x45/0x59 ? nfc_alloc_send_skb+0x2d/0xc0 __kasan_report.cold+0x117/0x11c ? mark_lock+0x480/0x4f0 ? nfc_alloc_send_skb+0x2d/0xc0 kasan_report+0x38/0x50 nfc_alloc_send_skb+0x2d/0xc0 nfc_llcp_send_ui_frame+0x18c/0x2a0 ? nfc_llcp_send_i_frame+0x230/0x230 ? __local_bh_enable_ip+0x86/0xe0 ? llcp_sock_connect+0x470/0x470 ? llcp_sock_connect+0x470/0x470 sock_sendmsg+0x8e/0xa0 ____sys_sendmsg+0x253/0x3f0 ... The issue was visible only with multiple simultaneous calls to bind() and sendmsg(), which resulted in most of the bind() calls to fail. The bind() was failing on checking if there is available WKS/SDP/SAP (respective bit in 'struct nfc_llcp_local' fields). When there was no available WKS/SDP/SAP, the bind returned error but the sendmsg() to such socket was able to trigger mentioned NULL pointer dereference of nfc_llcp_sock->dev. The code looks simply racy and currently it protects several paths against race with checks for (!nfc_llcp_sock->local) which is NULL-ified in error paths of bind(). The llcp_sock_sendmsg() did not have such check but called function nfc_llcp_send_ui_frame() had, although not protected with lock_sock(). Therefore the race could look like (same socket is used all the time): CPU0 CPU1 ==== ==== llcp_sock_bind() - lock_sock() - success - release_sock() - return 0 llcp_sock_sendmsg() - lock_sock() - release_sock() llcp_sock_bind(), same socket - lock_sock() - error - nfc_llcp_send_ui_frame() - if (!llcp_sock->local) - llcp_sock->local = NULL - nfc_put_device(dev) - dereference llcp_sock->dev - release_sock() - return -ERRNO The nfc_llcp_send_ui_frame() checked llcp_sock->local outside of the lock, which is racy and ineffective check. Instead, its caller llcp_sock_sendmsg(), should perform the check inside lock_sock(). Reported-and-tested-by: syzbot+7f23bcddf626e0593a39@syzkaller.appspotmail.com Fixes: b874dec ("NFC: Implement LLCP connection less Tx path") Cc: <stable@vger.kernel.org> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
kernel-patches-daemon-bpf bot
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Jan 26, 2024
Like commit 1cf3bfc ("bpf: Support 64-bit pointers to kfuncs") for s390x, add support for 64-bit pointers to kfuncs for LoongArch. Since the infrastructure is already implemented in BPF core, the only thing need to be done is to override bpf_jit_supports_far_kfunc_call(). Before this change, several test_verifier tests failed: # ./test_verifier | grep # | grep FAIL #119/p calls: invalid kfunc call: ptr_to_mem to struct with non-scalar FAIL #120/p calls: invalid kfunc call: ptr_to_mem to struct with nesting depth > 4 FAIL #121/p calls: invalid kfunc call: ptr_to_mem to struct with FAM FAIL #122/p calls: invalid kfunc call: reg->type != PTR_TO_CTX FAIL #123/p calls: invalid kfunc call: void * not allowed in func proto without mem size arg FAIL #124/p calls: trigger reg2btf_ids[reg->type] for reg->type > __BPF_REG_TYPE_MAX FAIL #125/p calls: invalid kfunc call: reg->off must be zero when passed to release kfunc FAIL #126/p calls: invalid kfunc call: don't match first member type when passed to release kfunc FAIL #127/p calls: invalid kfunc call: PTR_TO_BTF_ID with negative offset FAIL #128/p calls: invalid kfunc call: PTR_TO_BTF_ID with variable offset FAIL #129/p calls: invalid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID FAIL #130/p calls: valid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID FAIL #486/p map_kptr: ref: reference state created and released on xchg FAIL This is because the kfuncs in the loaded module are far away from __bpf_call_base: ffff800002009440 t bpf_kfunc_call_test_fail1 [bpf_testmod] 9000000002e128d8 T __bpf_call_base The offset relative to __bpf_call_base does NOT fit in s32, which breaks the assumption in BPF core. Enable bpf_jit_supports_far_kfunc_call() lifts this limit. Note that to reproduce the above result, tools/testing/selftests/bpf/config should be applied, and run the test with JIT enabled, unpriv BPF enabled. With this change, the test_verifier tests now all passed: # ./test_verifier ... Summary: 777 PASSED, 0 SKIPPED, 0 FAILED Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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The start_kthread() and stop_thread() code was not always called with the interface_lock held. This means that the kthread variable could be unexpectedly changed causing the kthread_stop() to be called on it when it should not have been, leading to: while true; do rtla timerlat top -u -q & PID=$!; sleep 5; kill -INT $PID; sleep 0.001; kill -TERM $PID; wait $PID; done Causing the following OOPS: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 5 UID: 0 PID: 885 Comm: timerlatu/5 Not tainted 6.11.0-rc4-test-00002-gbc754cc76d1b-dirty #125 a533010b71dab205ad2f507188ce8c82203b0254 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:hrtimer_active+0x58/0x300 Code: 48 c1 ee 03 41 54 48 01 d1 48 01 d6 55 53 48 83 ec 20 80 39 00 0f 85 30 02 00 00 49 8b 6f 30 4c 8d 75 10 4c 89 f0 48 c1 e8 03 <0f> b6 3c 10 4c 89 f0 83 e0 07 83 c0 03 40 38 f8 7c 09 40 84 ff 0f RSP: 0018:ffff88811d97f940 EFLAGS: 00010202 RAX: 0000000000000002 RBX: ffff88823c6b5b28 RCX: ffffed10478d6b6b RDX: dffffc0000000000 RSI: ffffed10478d6b6c RDI: ffff88823c6b5b28 RBP: 0000000000000000 R08: ffff88823c6b5b58 R09: ffff88823c6b5b60 R10: ffff88811d97f957 R11: 0000000000000010 R12: 00000000000a801d R13: ffff88810d8b35d8 R14: 0000000000000010 R15: ffff88823c6b5b28 FS: 0000000000000000(0000) GS:ffff88823c680000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000561858ad7258 CR3: 000000007729e001 CR4: 0000000000170ef0 Call Trace: <TASK> ? die_addr+0x40/0xa0 ? exc_general_protection+0x154/0x230 ? asm_exc_general_protection+0x26/0x30 ? hrtimer_active+0x58/0x300 ? __pfx_mutex_lock+0x10/0x10 ? __pfx_locks_remove_file+0x10/0x10 hrtimer_cancel+0x15/0x40 timerlat_fd_release+0x8e/0x1f0 ? security_file_release+0x43/0x80 __fput+0x372/0xb10 task_work_run+0x11e/0x1f0 ? _raw_spin_lock+0x85/0xe0 ? __pfx_task_work_run+0x10/0x10 ? poison_slab_object+0x109/0x170 ? do_exit+0x7a0/0x24b0 do_exit+0x7bd/0x24b0 ? __pfx_migrate_enable+0x10/0x10 ? __pfx_do_exit+0x10/0x10 ? __pfx_read_tsc+0x10/0x10 ? ktime_get+0x64/0x140 ? _raw_spin_lock_irq+0x86/0xe0 do_group_exit+0xb0/0x220 get_signal+0x17ba/0x1b50 ? vfs_read+0x179/0xa40 ? timerlat_fd_read+0x30b/0x9d0 ? __pfx_get_signal+0x10/0x10 ? __pfx_timerlat_fd_read+0x10/0x10 arch_do_signal_or_restart+0x8c/0x570 ? __pfx_arch_do_signal_or_restart+0x10/0x10 ? vfs_read+0x179/0xa40 ? ksys_read+0xfe/0x1d0 ? __pfx_ksys_read+0x10/0x10 syscall_exit_to_user_mode+0xbc/0x130 do_syscall_64+0x74/0x110 ? __pfx___rseq_handle_notify_resume+0x10/0x10 ? __pfx_ksys_read+0x10/0x10 ? fpregs_restore_userregs+0xdb/0x1e0 ? fpregs_restore_userregs+0xdb/0x1e0 ? syscall_exit_to_user_mode+0x116/0x130 ? do_syscall_64+0x74/0x110 ? do_syscall_64+0x74/0x110 ? do_syscall_64+0x74/0x110 entry_SYSCALL_64_after_hwframe+0x71/0x79 RIP: 0033:0x7ff0070eca9c Code: Unable to access opcode bytes at 0x7ff0070eca72. RSP: 002b:00007ff006dff8c0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00007ff0070eca9c RDX: 0000000000000400 RSI: 00007ff006dff9a0 RDI: 0000000000000003 RBP: 00007ff006dffde0 R08: 0000000000000000 R09: 00007ff000000ba0 R10: 00007ff007004b08 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ff006dff9a0 R14: 0000000000000007 R15: 0000000000000008 </TASK> Modules linked in: snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec snd_hwdep snd_hda_core ---[ end trace 0000000000000000 ]--- This is because it would mistakenly call kthread_stop() on a user space thread making it "exit" before it actually exits. Since kthreads are created based on global behavior, use a cpumask to know when kthreads are running and that they need to be shutdown before proceeding to do new work. Link: https://lore.kernel.org/all/20240820130001.124768-1-tglozar@redhat.com/ This was debugged by using the persistent ring buffer: Link: https://lore.kernel.org/all/20240823013902.135036960@goodmis.org/ Note, locking was originally used to fix this, but that proved to cause too many deadlocks to work around: https://lore.kernel.org/linux-trace-kernel/20240823102816.5e55753b@gandalf.local.home/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com> Link: https://lore.kernel.org/20240904103428.08efdf4c@gandalf.local.home Fixes: e88ed22 ("tracing/timerlat: Add user-space interface") Reported-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
kernel-patches-daemon-bpf bot
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Dec 2, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 2, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 3, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 3, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 3, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 3, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 3, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 4, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 5, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 6, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 6, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 6, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 7, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 9, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 9, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 9, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 9, 2024
Element replace (with a socket different from the one stored) may race with
socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with a
KASAN splat[1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may
have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811f5b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
kernel-patches-daemon-bpf bot
pushed a commit
that referenced
this pull request
Dec 10, 2024
Element replace (with a socket different from the one stored) may race
with socket's close() link popping & unlinking. __sock_map_delete()
unconditionally unrefs the (wrong) element:
// set map[0] = s0
map_update_elem(map, 0, s0)
// drop fd of s0
close(s0)
sock_map_close()
lock_sock(sk) (s0!)
sock_map_remove_links(sk)
link = sk_psock_link_pop()
sock_map_unlink(sk, link)
sock_map_delete_from_link
// replace map[0] with s1
map_update_elem(map, 0, s1)
sock_map_update_elem
(s1!) lock_sock(sk)
sock_map_update_common
psock = sk_psock(sk)
spin_lock(&stab->lock)
osk = stab->sks[idx]
sock_map_add_link(..., &stab->sks[idx])
sock_map_unref(osk, &stab->sks[idx])
psock = sk_psock(osk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test(&psock))
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
unlock_sock(sk)
__sock_map_delete
spin_lock(&stab->lock)
sk = *psk // s1 replaced s0; sk == s1
if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch
sk = xchg(psk, NULL)
if (sk)
sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle
psock = sk_psock(sk)
sk_psock_put(sk, psock)
if (refcount_dec_and_test())
sk_psock_drop(sk, psock)
spin_unlock(&stab->lock)
release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls
sock_map_free(). This results in some refcount_t warnings along with
a KASAN splat [1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that
may have been replaced.
[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
kasan_check_range+0x10f/0x1e0
sock_map_free+0x10e/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1202:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
unix_create1+0x88/0x8a0
unix_create+0xc5/0x180
__sock_create+0x241/0x650
__sys_socketpair+0x1ce/0x420
__x64_sys_socketpair+0x92/0x100
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
sk_psock_destroy+0x73e/0xa50
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
The buggy address belongs to the object at ffff88811f5b9080
which belongs to the cache UNIX-STREAM of size 1984
The buggy address is located 128 bytes inside of
freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888127d49401
flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000
head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401
head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Disabling lock debugging due to kernel taint
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125
Tainted: [B]=BAD_PAGE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xce/0x150
Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xce/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xce/0x150
sock_map_free+0x2e5/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
refcount_t: underflow; use-after-free.
WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
RIP: 0010:refcount_warn_saturate+0xee/0x150
Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7
RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349
R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000
R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024
FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
? __warn.cold+0x5f/0x1ff
? refcount_warn_saturate+0xee/0x150
? report_bug+0x1ec/0x390
? handle_bug+0x58/0x90
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0xee/0x150
sock_map_free+0x2d3/0x330
bpf_map_free_deferred+0x173/0x320
process_one_work+0x846/0x1420
worker_thread+0x5b3/0xf80
kthread+0x29e/0x360
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 10741
hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20
hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770
softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210
Fixes: 604326b ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20241202-sockmap-replace-v1-3-1e88579e7bd5@rbox.co
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Pull request for series with
subject: libbpf: BTF writer APIs
version: 3
url: https://patchwork.ozlabs.org/project/netdev/list/?series=204718