[syzkaller] Use-after-free in subflow_state_change #250
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matttbe
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Dec 17, 2021
The self-tests in a loop triggered a UaF similar to: #250 The critical scenario is actually almost fixed by: "mptcp: cleanup MPJ subflow list handling" with a notable exception: if an MPJ handshake races with mptcp_close(), the subflow enter the join_list and __mptcp_finish_join() is processed at the msk socket lock release in mptcp_close(), the subflow will preserver a danfling reference to the msk sk_socket. Address the issue fragting the subflow only on successful __mptcp_finish_join() Note that issues/250 triggers even before "mptcp: cleanup MPJ subflow list handling", as before such commit the join list was not spliced by mptcp_close(). We could consider a net-only patch to address that. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
jenkins-tessares
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Dec 31, 2021
Hulk robot reported a kmemleak problem:
unreferenced object 0xffff93d1d8cc02e8 (size 248):
comm "cat", pid 23327, jiffies 4624670141 (age 495992.217s)
hex dump (first 32 bytes):
00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@..............
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
seq_open+0x2a/0x80
full_proxy_open+0x167/0x1e0
do_dentry_open+0x1e1/0x3a0
path_openat+0x961/0xa20
do_filp_open+0xae/0x120
do_sys_openat2+0x216/0x2f0
do_sys_open+0x57/0x80
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
unreferenced object 0xffff93d419854000 (size 4096):
comm "cat", pid 23327, jiffies 4624670141 (age 495992.217s)
hex dump (first 32 bytes):
6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0
30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda12-
backtrace:
seq_read_iter+0x313/0x440
seq_read+0x14b/0x1a0
full_proxy_read+0x56/0x80
vfs_read+0xa5/0x1b0
ksys_read+0xa0/0xf0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
I find that we can easily reproduce this problem with the following
commands:
cat /sys/kernel/debug/kfence/objects
echo scan > /sys/kernel/debug/kmemleak
cat /sys/kernel/debug/kmemleak
The leaked memory is allocated in the stack below:
do_syscall_64
do_sys_open
do_dentry_open
full_proxy_open
seq_open ---> alloc seq_file
vfs_read
full_proxy_read
seq_read
seq_read_iter
traverse ---> alloc seq_buf
And it should have been released in the following process:
do_syscall_64
syscall_exit_to_user_mode
exit_to_user_mode_prepare
task_work_run
____fput
__fput
full_proxy_release ---> free here
However, the release function corresponding to file_operations is not
implemented in kfence. As a result, a memory leak occurs. Therefore,
the solution to this problem is to implement the corresponding release
function.
Link: https://lkml.kernel.org/r/20211206133628.2822545-1-libaokun1@huawei.com
Fixes: 0ce20dd ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Please note that in our tree we have a fix for the "export branch": But we still have an issue in -net and we still need a dedicated patch for that:
I didn't close issues/250 for this reason. Assigning @pabeni on this one because I thought you were looking at a patch for this one but if not, please tell me :-) |
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as per public meeting discussion, this is probably not worthy a stable-only patch. |
jenkins-tessares
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Jul 20, 2023
Add a big batch of test coverage to assert all aspects of the tcx opts attach, detach and query API: # ./vmtest.sh -- ./test_progs -t tc_opts [...] #238 tc_opts_after:OK #239 tc_opts_append:OK #240 tc_opts_basic:OK #241 tc_opts_before:OK #242 tc_opts_chain_classic:OK #243 tc_opts_demixed:OK #244 tc_opts_detach:OK #245 tc_opts_detach_after:OK #246 tc_opts_detach_before:OK #247 tc_opts_dev_cleanup:OK #248 tc_opts_invalid:OK #249 tc_opts_mixed:OK #250 tc_opts_prepend:OK #251 tc_opts_replace:OK #252 tc_opts_revision:OK Summary: 15/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20230719140858.13224-8-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org>
jenkins-tessares
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Aug 11, 2023
Add a detachment test case with miniq present to assert that with and without the miniq we get the same error. # ./test_progs -t tc_opts #244 tc_opts_after:OK #245 tc_opts_append:OK #246 tc_opts_basic:OK #247 tc_opts_before:OK #248 tc_opts_chain_classic:OK #249 tc_opts_delete_empty:OK #250 tc_opts_demixed:OK #251 tc_opts_detach:OK #252 tc_opts_detach_after:OK #253 tc_opts_detach_before:OK #254 tc_opts_dev_cleanup:OK #255 tc_opts_invalid:OK #256 tc_opts_mixed:OK #257 tc_opts_prepend:OK #258 tc_opts_replace:OK #259 tc_opts_revision:OK Summary: 16/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20230804131112.11012-2-daniel@iogearbox.net Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
matttbe
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Aug 17, 2023
Add several new tcx test cases to improve test coverage. This also includes a few new tests with ingress instead of clsact qdisc, to cover the fix from commit dc644b5 ("tcx: Fix splat in ingress_destroy upon tcx_entry_free"). # ./test_progs -t tc [...] #234 tc_links_after:OK #235 tc_links_append:OK #236 tc_links_basic:OK #237 tc_links_before:OK #238 tc_links_chain_classic:OK #239 tc_links_chain_mixed:OK #240 tc_links_dev_cleanup:OK #241 tc_links_dev_mixed:OK #242 tc_links_ingress:OK #243 tc_links_invalid:OK #244 tc_links_prepend:OK #245 tc_links_replace:OK #246 tc_links_revision:OK #247 tc_opts_after:OK #248 tc_opts_append:OK #249 tc_opts_basic:OK #250 tc_opts_before:OK #251 tc_opts_chain_classic:OK #252 tc_opts_chain_mixed:OK #253 tc_opts_delete_empty:OK #254 tc_opts_demixed:OK #255 tc_opts_detach:OK #256 tc_opts_detach_after:OK #257 tc_opts_detach_before:OK #258 tc_opts_dev_cleanup:OK #259 tc_opts_invalid:OK #260 tc_opts_mixed:OK #261 tc_opts_prepend:OK #262 tc_opts_replace:OK #263 tc_opts_revision:OK [...] Summary: 44/38 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/8699efc284b75ccdc51ddf7062fa2370330dc6c0.1692029283.git.daniel@iogearbox.net Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
matttbe
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Jul 5, 2024
Only export struct fb_info.fix.smem_start if that is required by the user and the memory does not come from vmalloc(). Setting struct fb_info.fix.smem_start breaks systems where DMA memory is backed by vmalloc address space. An example error is shown below. [ 3.536043] ------------[ cut here ]------------ [ 3.540716] virt_to_phys used for non-linear address: 000000007fc4f540 (0xffff800086001000) [ 3.552628] WARNING: CPU: 4 PID: 61 at arch/arm64/mm/physaddr.c:12 __virt_to_phys+0x68/0x98 [ 3.565455] Modules linked in: [ 3.568525] CPU: 4 PID: 61 Comm: kworker/u12:5 Not tainted 6.6.23-06226-g4986cc3e1b75-dirty #250 [ 3.577310] Hardware name: NXP i.MX95 19X19 board (DT) [ 3.582452] Workqueue: events_unbound deferred_probe_work_func [ 3.588291] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 3.595233] pc : __virt_to_phys+0x68/0x98 [ 3.599246] lr : __virt_to_phys+0x68/0x98 [ 3.603276] sp : ffff800083603990 [ 3.677939] Call trace: [ 3.680393] __virt_to_phys+0x68/0x98 [ 3.684067] drm_fbdev_dma_helper_fb_probe+0x138/0x238 [ 3.689214] __drm_fb_helper_initial_config_and_unlock+0x2b0/0x4c0 [ 3.695385] drm_fb_helper_initial_config+0x4c/0x68 [ 3.700264] drm_fbdev_dma_client_hotplug+0x8c/0xe0 [ 3.705161] drm_client_register+0x60/0xb0 [ 3.709269] drm_fbdev_dma_setup+0x94/0x148 Additionally, DMA memory is assumed to by contiguous in physical address space, which is not guaranteed by vmalloc(). Resolve this by checking the module flag drm_leak_fbdev_smem when DRM allocated the instance of struct fb_info. Fbdev-dma then only sets smem_start only if required (via FBINFO_HIDE_SMEM_START). Also guarantee that the framebuffer is not located in vmalloc address space. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reported-by: Peng Fan (OSS) <peng.fan@oss.nxp.com> Closes: https://lore.kernel.org/dri-devel/20240604080328.4024838-1-peng.fan@oss.nxp.com/ Reported-by: Geert Uytterhoeven <geert+renesas@glider.be> Closes: https://lore.kernel.org/dri-devel/CAMuHMdX3N0szUvt1VTbroa2zrT1Nye_VzPb5qqCZ7z5gSm7HGw@mail.gmail.com/ Fixes: a51c766 ("drm/fb-helper: Consolidate CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM") Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: <stable@vger.kernel.org> # v6.4+ Link: https://patchwork.freedesktop.org/patch/msgid/20240617152843.11886-1-tzimmermann@suse.de
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Syzkaller reports a UAF in __subflow_state_change()
Export branch, tag export/20211209T054821
config: syz.config.gz
full syzkaller log: log0.gz
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