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Provide a single call to allow kernel code to determine whether the system has been configured to either disable module loading entirely or to load only modules signed with a trusted key. Bugzilla: N/A Upstream-status: Fedora mustard. Replaced by securelevels, but that was nak'd Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Any hardware that can potentially generate DMA has to be locked down from userspace in order to avoid it being possible for an attacker to modify kernel code, allowing them to circumvent disabled module loading or module signing. Default to paranoid - in future we can potentially relax this for sufficiently IOMMU-isolated devices. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
IO port access would permit users to gain access to PCI configuration registers, which in turn (on a lot of hardware) give access to MMIO register space. This would potentially permit root to trigger arbitrary DMA, so lock it down by default. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
custom_method effectively allows arbitrary access to system memory, making it possible for an attacker to circumvent restrictions on module loading. Disable it if any such restrictions have been enabled. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
We have no way of validating what all of the Asus WMI methods do on a given machine, and there's a risk that some will allow hardware state to be manipulated in such a way that arbitrary code can be executed in the kernel, circumventing module loading restrictions. Prevent that if any of these features are enabled. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Allowing users to write to address space makes it possible for the kernel to be subverted, avoiding module loading restrictions. Prevent this when any restrictions have been imposed on loading modules. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
…cted This option allows userspace to pass the RSDP address to the kernel, which makes it possible for a user to circumvent any restrictions imposed on loading modules. Disable it in that case. Signed-off-by: Josh Boyer <jwboyer@redhat.com>
…ictions kexec permits the loading and execution of arbitrary code in ring 0, which is something that module signing enforcement is meant to prevent. It makes sense to disable kexec in this situation. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Writing to MSRs should not be allowed if module loading is restricted, since it could lead to execution of arbitrary code in kernel mode. Based on a patch by Kees Cook. Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
…Boot mode UEFI Secure Boot provides a mechanism for ensuring that the firmware will only load signed bootloaders and kernels. Certain use cases may also require that all kernel modules also be signed. Add a configuration option that enforces this automatically when enabled. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
The functionality of the config option is dependent upon the platform being UEFI based. Reflect this in the config deps. Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
UEFI machines can be booted in Secure Boot mode. Add a EFI_SECURE_BOOT bit for use with efi_enabled. Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
There is currently no way to verify the resume image when returning from hibernate. This might compromise the signed modules trust model, so until we can work with signed hibernate images we disable it in a secure modules environment. Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
This enables relocating source and build trees to different roots, provided they stay reachable relative to one another. Useful for builds done within a sandbox where the eventual root is prefixed by some undesirable path component.
Signed-off-by: Geoff Levand <geoff@infradead.org>
…espaces commit aad8289 ("selinux: Add support for unprivileged mounts from user namespaces") prohibited any use of context mount options within non-init user namespaces. However, this breaks use of context mount options for tmpfs mounts within user namespaces, which are being used by Docker/runc. There is no reason to block such usage for tmpfs, ramfs or devpts. Exempt these filesystem types from this restriction. Before: sh$ userns_child_exec -p -m -U -M '0 1000 1' -G '0 1000 1' bash sh# mount -t tmpfs -o context=system_u:object_r:user_tmp_t:s0:c13 none /tmp mount: tmpfs is write-protected, mounting read-only mount: cannot mount tmpfs read-only After: sh$ userns_child_exec -p -m -U -M '0 1000 1' -G '0 1000 1' bash sh# mount -t tmpfs -o context=system_u:object_r:user_tmp_t:s0:c13 none /tmp sh# ls -Zd /tmp unconfined_u:object_r:user_tmp_t:s0:c13 /tmp Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
bgilbert
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[ Upstream commit ddc665a ] When the instruction right before the branch destination is a 64 bit load immediate, we currently calculate the wrong jump offset in the ctx->offset[] array as we only account one instruction slot for the 64 bit load immediate although it uses two BPF instructions. Fix it up by setting the offset into the right slot after we incremented the index. Before (ldimm64 test 1): [...] 00000020: 52800007 mov w7, #0x0 // #0 00000024: d2800060 mov x0, #0x3 // #3 00000028: d2800041 mov x1, #0x2 // #2 0000002c: eb01001f cmp x0, x1 00000030: 54ffff82 b.cs 0x00000020 00000034: d29fffe7 mov x7, #0xffff // #65535 00000038: f2bfffe7 movk x7, #0xffff, lsl #16 0000003c: f2dfffe7 movk x7, #0xffff, lsl #32 00000040: f2ffffe7 movk x7, #0xffff, lsl #48 00000044: d29dddc7 mov x7, #0xeeee // #61166 00000048: f2bdddc7 movk x7, #0xeeee, lsl #16 0000004c: f2ddddc7 movk x7, #0xeeee, lsl #32 00000050: f2fdddc7 movk x7, #0xeeee, lsl #48 [...] After (ldimm64 test 1): [...] 00000020: 52800007 mov w7, #0x0 // #0 00000024: d2800060 mov x0, #0x3 // #3 00000028: d2800041 mov x1, #0x2 // #2 0000002c: eb01001f cmp x0, x1 00000030: 540000a2 b.cs 0x00000044 00000034: d29fffe7 mov x7, #0xffff // #65535 00000038: f2bfffe7 movk x7, #0xffff, lsl #16 0000003c: f2dfffe7 movk x7, #0xffff, lsl #32 00000040: f2ffffe7 movk x7, #0xffff, lsl #48 00000044: d29dddc7 mov x7, #0xeeee // #61166 00000048: f2bdddc7 movk x7, #0xeeee, lsl #16 0000004c: f2ddddc7 movk x7, #0xeeee, lsl #32 00000050: f2fdddc7 movk x7, #0xeeee, lsl #48 [...] Also, add a couple of test cases to make sure JITs pass this test. Tested on Cavium ThunderX ARMv8. The added test cases all pass after the fix. Fixes: 8eee539 ("arm64: bpf: fix out-of-bounds read in bpf2a64_offset()") Reported-by: David S. Miller <davem@davemloft.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Xi Wang <xi.wang@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 36b6f9f ] Lockdep warns about a potential deadlock: [ 66.782842] ====================================================== [ 66.782888] WARNING: possible circular locking dependency detected [ 66.782937] 4.14.0-rc2-test-test+ #48 Not tainted [ 66.782983] ------------------------------------------------------ [ 66.783052] umount/336 is trying to acquire lock: [ 66.783117] (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff81032395>] rdt_kill_sb+0x215/0x390 [ 66.783193] but task is already holding lock: [ 66.783244] (rdtgroup_mutex){+.+.}, at: [<ffffffff810321b6>] rdt_kill_sb+0x36/0x390 [ 66.783305] which lock already depends on the new lock. [ 66.783364] the existing dependency chain (in reverse order) is: [ 66.783419] -> #3 (rdtgroup_mutex){+.+.}: [ 66.783467] __lock_acquire+0x1293/0x13f0 [ 66.783509] lock_acquire+0xaf/0x220 [ 66.783543] __mutex_lock+0x71/0x9b0 [ 66.783575] mutex_lock_nested+0x1b/0x20 [ 66.783610] intel_rdt_online_cpu+0x3b/0x430 [ 66.783649] cpuhp_invoke_callback+0xab/0x8e0 [ 66.783687] cpuhp_thread_fun+0x7a/0x150 [ 66.783722] smpboot_thread_fn+0x1cc/0x270 [ 66.783764] kthread+0x16e/0x190 [ 66.783794] ret_from_fork+0x27/0x40 [ 66.783825] -> #2 (cpuhp_state){+.+.}: [ 66.783870] __lock_acquire+0x1293/0x13f0 [ 66.783906] lock_acquire+0xaf/0x220 [ 66.783938] cpuhp_issue_call+0x102/0x170 [ 66.783974] __cpuhp_setup_state_cpuslocked+0x154/0x2a0 [ 66.784023] __cpuhp_setup_state+0xc7/0x170 [ 66.784061] page_writeback_init+0x43/0x67 [ 66.784097] pagecache_init+0x43/0x4a [ 66.784131] start_kernel+0x3ad/0x3f7 [ 66.784165] x86_64_start_reservations+0x2a/0x2c [ 66.784204] x86_64_start_kernel+0x72/0x75 [ 66.784241] verify_cpu+0x0/0xfb [ 66.784270] -> #1 (cpuhp_state_mutex){+.+.}: [ 66.784319] __lock_acquire+0x1293/0x13f0 [ 66.784355] lock_acquire+0xaf/0x220 [ 66.784387] __mutex_lock+0x71/0x9b0 [ 66.784419] mutex_lock_nested+0x1b/0x20 [ 66.784454] __cpuhp_setup_state_cpuslocked+0x52/0x2a0 [ 66.784497] __cpuhp_setup_state+0xc7/0x170 [ 66.784535] page_alloc_init+0x28/0x30 [ 66.784569] start_kernel+0x148/0x3f7 [ 66.784602] x86_64_start_reservations+0x2a/0x2c [ 66.784642] x86_64_start_kernel+0x72/0x75 [ 66.784678] verify_cpu+0x0/0xfb [ 66.784707] -> #0 (cpu_hotplug_lock.rw_sem){++++}: [ 66.784759] check_prev_add+0x32f/0x6e0 [ 66.784794] __lock_acquire+0x1293/0x13f0 [ 66.784830] lock_acquire+0xaf/0x220 [ 66.784863] cpus_read_lock+0x3d/0xb0 [ 66.784896] rdt_kill_sb+0x215/0x390 [ 66.784930] deactivate_locked_super+0x3e/0x70 [ 66.784968] deactivate_super+0x40/0x60 [ 66.785003] cleanup_mnt+0x3f/0x80 [ 66.785034] __cleanup_mnt+0x12/0x20 [ 66.785070] task_work_run+0x8b/0xc0 [ 66.785103] exit_to_usermode_loop+0x94/0xa0 [ 66.786804] syscall_return_slowpath+0xe8/0x150 [ 66.788502] entry_SYSCALL_64_fastpath+0xab/0xad [ 66.790194] other info that might help us debug this: [ 66.795139] Chain exists of: cpu_hotplug_lock.rw_sem --> cpuhp_state --> rdtgroup_mutex [ 66.800035] Possible unsafe locking scenario: [ 66.803267] CPU0 CPU1 [ 66.804867] ---- ---- [ 66.806443] lock(rdtgroup_mutex); [ 66.808002] lock(cpuhp_state); [ 66.809565] lock(rdtgroup_mutex); [ 66.811110] lock(cpu_hotplug_lock.rw_sem); [ 66.812608] *** DEADLOCK *** [ 66.816983] 2 locks held by umount/336: [ 66.818418] #0: (&type->s_umount_key#35){+.+.}, at: [<ffffffff81229738>] deactivate_super+0x38/0x60 [ 66.819922] #1: (rdtgroup_mutex){+.+.}, at: [<ffffffff810321b6>] rdt_kill_sb+0x36/0x390 When the resctrl filesystem is unmounted the locks should be obtain in the locks in the same order as was done when the cpus came online: cpu_hotplug_lock before rdtgroup_mutex. This also requires to switch the static_branch_disable() calls to the _cpulocked variant because now cpu hotplug lock is held already. [ tglx: Switched to cpus_read_[un]lock ] Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Acked-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> Acked-by: Fenghua Yu <fenghua.yu@intel.com> Acked-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/cc292e76be073f7260604651711c47b09fd0dc81.1508490116.git.reinette.chatre@intel.com Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Sep 5, 2018
[ Upstream commit 92a4728 ] Dirk Gouders reported that two consecutive "make" invocations on an already compiled tree will show alternating behaviors: $ make CALL scripts/checksyscalls.sh DESCEND objtool CHK include/generated/compile.h DATAREL arch/x86/boot/compressed/vmlinux Kernel: arch/x86/boot/bzImage is ready (#48) Building modules, stage 2. MODPOST 165 modules $ make CALL scripts/checksyscalls.sh DESCEND objtool CHK include/generated/compile.h LD arch/x86/boot/compressed/vmlinux ZOFFSET arch/x86/boot/zoffset.h AS arch/x86/boot/header.o LD arch/x86/boot/setup.elf OBJCOPY arch/x86/boot/setup.bin OBJCOPY arch/x86/boot/vmlinux.bin BUILD arch/x86/boot/bzImage Setup is 15644 bytes (padded to 15872 bytes). System is 6663 kB CRC 3eb90f40 Kernel: arch/x86/boot/bzImage is ready (#48) Building modules, stage 2. MODPOST 165 modules He bisected it back to: commit 98f7852 ("x86/boot: Refuse to build with data relocations") The root cause was the use of the "if_changed" kbuild function multiple times for the same target. It was designed to only be used once per target, otherwise it will effectively always trigger, flipping back and forth between the two commands getting recorded by "if_changed". Instead, this patch merges the two commands into a single function to get stable build artifacts (i.e. .vmlinux.cmd), and a single build behavior. Bisected-and-Reported-by: Dirk Gouders <dirk@gouders.net> Fix-Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180724230827.GA37823@beast Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Apr 17, 2020
[ Upstream commit dd09fad ] Commit: 3a6b6c6 ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE initialization common across all architectures") moved the call to efi_memattr_init() from ARM specific to the generic EFI init code, in order to be able to apply the restricted permissions described in that table on x86 as well. We never enabled this feature fully on i386, and so mapping and reserving this table is pointless. However, due to the early call to memblock_reserve(), the memory bookkeeping gets confused to the point where it produces the splat below when we try to map the memory later on: ------------[ cut here ]------------ ioremap on RAM at 0x3f251000 - 0x3fa1afff WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:166 __ioremap_caller ... Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.20.0 #48 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 EIP: __ioremap_caller.constprop.0+0x249/0x260 Code: 90 0f b7 05 4e 38 40 de 09 45 e0 e9 09 ff ff ff 90 8d 45 ec c6 05 ... EAX: 00000029 EBX: 00000000 ECX: de59c228 EDX: 00000001 ESI: 3f250fff EDI: 00000000 EBP: de3edf20 ESP: de3edee0 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00200296 CR0: 80050033 CR2: ffd17000 CR3: 1e58c000 CR4: 00040690 Call Trace: ioremap_cache+0xd/0x10 ? old_map_region+0x72/0x9d old_map_region+0x72/0x9d efi_map_region+0x8/0xa efi_enter_virtual_mode+0x260/0x43b start_kernel+0x329/0x3aa i386_start_kernel+0xa7/0xab startup_32_smp+0x164/0x168 ---[ end trace e15ccf6b9f356833 ]--- Let's work around this by disregarding the memory attributes table altogether on i386, which does not result in a loss of functionality or protection, given that we never consumed the contents. Fixes: 3a6b6c6 ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE ... ") Tested-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200304165917.5893-1-ardb@kernel.org Link: https://lore.kernel.org/r/20200308080859.21568-21-ardb@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
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…f fs_info::journal_info commit fcc9973 upstream. [BUG] One run of btrfs/063 triggered the following lockdep warning: ============================================ WARNING: possible recursive locking detected 5.6.0-rc7-custom+ #48 Not tainted -------------------------------------------- kworker/u24:0/7 is trying to acquire lock: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] but task is already holding lock: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sb_internal#2); lock(sb_internal#2); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by kworker/u24:0/7: #0: ffff88817b495948 ((wq_completion)btrfs-endio-write){+.+.}, at: process_one_work+0x557/0xb80 #1: ffff888189ea7db8 ((work_completion)(&work->normal_work)){+.+.}, at: process_one_work+0x557/0xb80 #2: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] #3: ffff888174ca4da8 (&fs_info->reloc_mutex){+.+.}, at: btrfs_record_root_in_trans+0x83/0xd0 [btrfs] stack backtrace: CPU: 0 PID: 7 Comm: kworker/u24:0 Not tainted 5.6.0-rc7-custom+ #48 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: btrfs-endio-write btrfs_work_helper [btrfs] Call Trace: dump_stack+0xc2/0x11a __lock_acquire.cold+0xce/0x214 lock_acquire+0xe6/0x210 __sb_start_write+0x14e/0x290 start_transaction+0x66c/0x890 [btrfs] btrfs_join_transaction+0x1d/0x20 [btrfs] find_free_extent+0x1504/0x1a50 [btrfs] btrfs_reserve_extent+0xd5/0x1f0 [btrfs] btrfs_alloc_tree_block+0x1ac/0x570 [btrfs] btrfs_copy_root+0x213/0x580 [btrfs] create_reloc_root+0x3bd/0x470 [btrfs] btrfs_init_reloc_root+0x2d2/0x310 [btrfs] record_root_in_trans+0x191/0x1d0 [btrfs] btrfs_record_root_in_trans+0x90/0xd0 [btrfs] start_transaction+0x16e/0x890 [btrfs] btrfs_join_transaction+0x1d/0x20 [btrfs] btrfs_finish_ordered_io+0x55d/0xcd0 [btrfs] finish_ordered_fn+0x15/0x20 [btrfs] btrfs_work_helper+0x116/0x9a0 [btrfs] process_one_work+0x632/0xb80 worker_thread+0x80/0x690 kthread+0x1a3/0x1f0 ret_from_fork+0x27/0x50 It's pretty hard to reproduce, only one hit so far. [CAUSE] This is because we're calling btrfs_join_transaction() without re-using the current running one: btrfs_finish_ordered_io() |- btrfs_join_transaction() <<< Call #1 |- btrfs_record_root_in_trans() |- btrfs_reserve_extent() |- btrfs_join_transaction() <<< Call #2 Normally such btrfs_join_transaction() call should re-use the existing one, without trying to re-start a transaction. But the problem is, in btrfs_join_transaction() call #1, we call btrfs_record_root_in_trans() before initializing current::journal_info. And in btrfs_join_transaction() call #2, we're relying on current::journal_info to avoid such deadlock. [FIX] Call btrfs_record_root_in_trans() after we have initialized current::journal_info. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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