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| author | Filipe Manana <fdmanana@suse.com> | 2019-08-12 21:14:29 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2019-09-09 15:59:11 +0300 |
| commit | efad8a853ad2057f96664328a0d327a05ce39c76 (patch) | |
| tree | 77ab51b1bcf39c1b656330913a85f39f0a52df25 /drivers/extcon/extcon-fsa9480.c | |
| parent | 27e022a9c6fe97dd80e31c038328d4f79b2080c2 (diff) | |
| download | linux-efad8a853ad2057f96664328a0d327a05ce39c76.tar.xz | |
Btrfs: fix use-after-free when using the tree modification log
At ctree.c:get_old_root(), we are accessing a root's header owner field
after we have freed the respective extent buffer. This results in an
use-after-free that can lead to crashes, and when CONFIG_DEBUG_PAGEALLOC
is set, results in a stack trace like the following:
[ 3876.799331] stack segment: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
[ 3876.799363] CPU: 0 PID: 15436 Comm: pool Not tainted 5.3.0-rc3-btrfs-next-54 #1
[ 3876.799385] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
[ 3876.799433] RIP: 0010:btrfs_search_old_slot+0x652/0xd80 [btrfs]
(...)
[ 3876.799502] RSP: 0018:ffff9f08c1a2f9f0 EFLAGS: 00010286
[ 3876.799518] RAX: ffff8dd300000000 RBX: ffff8dd85a7a9348 RCX: 000000038da26000
[ 3876.799538] RDX: 0000000000000000 RSI: ffffe522ce368980 RDI: 0000000000000246
[ 3876.799559] RBP: dae1922adadad000 R08: 0000000008020000 R09: ffffe522c0000000
[ 3876.799579] R10: ffff8dd57fd788c8 R11: 000000007511b030 R12: ffff8dd781ddc000
[ 3876.799599] R13: ffff8dd9e6240578 R14: ffff8dd6896f7a88 R15: ffff8dd688cf90b8
[ 3876.799620] FS: 00007f23ddd97700(0000) GS:ffff8dda20200000(0000) knlGS:0000000000000000
[ 3876.799643] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3876.799660] CR2: 00007f23d4024000 CR3: 0000000710bb0005 CR4: 00000000003606f0
[ 3876.799682] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3876.799703] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3876.799723] Call Trace:
[ 3876.799735] ? do_raw_spin_unlock+0x49/0xc0
[ 3876.799749] ? _raw_spin_unlock+0x24/0x30
[ 3876.799779] resolve_indirect_refs+0x1eb/0xc80 [btrfs]
[ 3876.799810] find_parent_nodes+0x38d/0x1180 [btrfs]
[ 3876.799841] btrfs_check_shared+0x11a/0x1d0 [btrfs]
[ 3876.799870] ? extent_fiemap+0x598/0x6e0 [btrfs]
[ 3876.799895] extent_fiemap+0x598/0x6e0 [btrfs]
[ 3876.799913] do_vfs_ioctl+0x45a/0x700
[ 3876.799926] ksys_ioctl+0x70/0x80
[ 3876.799938] ? trace_hardirqs_off_thunk+0x1a/0x20
[ 3876.799953] __x64_sys_ioctl+0x16/0x20
[ 3876.799965] do_syscall_64+0x62/0x220
[ 3876.799977] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 3876.799993] RIP: 0033:0x7f23e0013dd7
(...)
[ 3876.800056] RSP: 002b:00007f23ddd96ca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 3876.800078] RAX: ffffffffffffffda RBX: 00007f23d80210f8 RCX: 00007f23e0013dd7
[ 3876.800099] RDX: 00007f23d80210f8 RSI: 00000000c020660b RDI: 0000000000000003
[ 3876.800626] RBP: 000055fa2a2a2440 R08: 0000000000000000 R09: 00007f23ddd96d7c
[ 3876.801143] R10: 00007f23d8022000 R11: 0000000000000246 R12: 00007f23ddd96d80
[ 3876.801662] R13: 00007f23ddd96d78 R14: 00007f23d80210f0 R15: 00007f23ddd96d80
(...)
[ 3876.805107] ---[ end trace e53161e179ef04f9 ]---
Fix that by saving the root's header owner field into a local variable
before freeing the root's extent buffer, and then use that local variable
when needed.
Fixes: 30b0463a9394d9 ("Btrfs: fix accessing the root pointer in tree mod log functions")
CC: stable@vger.kernel.org # 3.10+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'drivers/extcon/extcon-fsa9480.c')
0 files changed, 0 insertions, 0 deletions