KASAN: slab-use-after-free in find_lock_entries+0x21e/0x1160

[白烁冉]

Dear Maintainers,

When using our customized Syzkaller to fuzz the latest Linux kernel, the following crash (91th)was triggered.


HEAD commit: 6537cfb395f352782918d8ee7b7f10ba2cc3cbf2
git tree: upstream
Output:https://github.com/pghk13/Kernel-Bug/tree/main/0305_6.14rc3/91-KASAN_%20global-out-of-bounds%20Write%20in%20pcpu_alloc
Kernel config:https://github.com/pghk13/Kernel-Bug/blob/main/0305_6.14rc3/config.txt
C reproducer:https:https://github.com/pghk13/Kernel-Bug/blob/main/0305_6.14rc3/91-KASAN_%20global-out-of-bounds%20Write%20in%20pcpu_alloc/91repro.c
Syzlang reproducer: https://github.com/pghk13/Kernel-Bug/blob/main/0305_6.14rc3/91-KASAN_%20global-out-of-bounds%20Write%20in%20pcpu_alloc/91repro.txt



Our reproducer uses mounts a constructed filesystem image.
The system call shmem_undo_range call find_lock_entries to find and lock the folio, and it is possible that when a folio fails to lock or the mapping does not match, the code will release the folio through a goto put jump, but then it is possible to use the released folio on line 2153.
We have reproduced this issue several times on 6.14-rc5 again.








If you fix this issue, please add the following tag to the commit:
Reported-by: Kun Hu <huk23@xxxxxxxxxxxxxx>, Jiaji Qin <jjtan24@xxxxxxxxxxxxxx>, Shuoran Bai <baishuoran@xxxxxxxxxxxx>

==================================================================
BUG: KASAN: slab-use-after-free in find_lock_entries+0x21e/0x1160
Read of size 4 at addr ffff88807917d8f4 by task syz.0.32/15410

CPU: 3 UID: 0 PID: 15410 Comm: syz.0.32 Not tainted 6.14.0-rc5 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x116/0x1b0
 print_report+0xc1/0x630
 kasan_report+0x93/0xc0
 kasan_check_range+0xed/0x1a0
 find_lock_entries+0x21e/0x1160
 shmem_undo_range+0x205/0x11b0
 shmem_truncate_range+0x30/0xd0
 shmem_evict_inode+0x2ec/0xa00
 evict+0x3f2/0x860
 iput+0x51c/0x830
 dentry_unlink_inode+0x2cd/0x4c0
 __dentry_kill+0x186/0x5b0
 dput.part.0+0x49e/0x990
 dput+0x1f/0x30
 __fput+0x52b/0xb60
 task_work_run+0x173/0x280
 syscall_exit_to_user_mode+0x29e/0x2a0
 do_syscall_64+0xdc/0x250
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2da111ebdb
Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2f 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007f2da20839a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000000000000597f RCX: 00007f2da111ebdb
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003
RBP: 00007f2da20846b0 R08: 0000000000000000 R09: 0000000000800000
R10: 0000000000000000 R11: 0000000000000293 R12: ffffffffffffffff
R13: 0000000000000016 R14: 0000000000000003 R15: 0000000020005bc0
 </TASK>

Allocated by task 30372096:
------------[ cut here ]------------
pool index 125439 out of bounds (850) for stack id ffffea00
WARNING: CPU: 3 PID: 15410 at lib/stackdepot.c:451 depot_fetch_stack+0x96/0xc0
Modules linked in:
CPU: 3 UID: 0 PID: 15410 Comm: syz.0.32 Not tainted 6.14.0-rc5 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:depot_fetch_stack+0x96/0xc0
Code: f8 7a d7 8e e8 6b ee 5a 06 83 f8 01 75 b8 90 0f 0b 90 eb b2 90 48 c7 c7 b8 66 90 8d 44 89 e1 44 89 ea 89 ee e8 bb 03 7c fc 90 <0f> 0b 90 90 31 c0 eb bb 90 0f 0b 90 eb b5 90 0f 0b 90 31 c0 eb ad
RSP: 0018:ffffc900024f7480 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000003ff0 RCX: ffffffff8179ec7a
RDX: 0000000000000000 RSI: ffff88806f728000 RDI: 0000000000000002
RBP: 000000000001e9ff R08: fffffbfff1c0b800 R09: ffffed100fde5182
R10: ffffed100fde5181 R11: ffff88807ef28c0b R12: 00000000ffffea00
R13: 0000000000000352 R14: ffffffff81f0b71e R15: 0000000000000001
FS:  00007f2da2084700(0000) GS:ffff88807ef00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f52e19ff000 CR3: 000000006aa74000 CR4: 0000000000750ef0
PKRU: 00000000
Call Trace:
 <TASK>
 stack_depot_fetch.part.0+0x9/0x40
 stack_depot_print+0x4e/0x70
 print_report+0x5ff/0x630
 kasan_report+0x93/0xc0
 kasan_check_range+0xed/0x1a0
 find_lock_entries+0x21e/0x1160
 shmem_undo_range+0x205/0x11b0
 shmem_truncate_range+0x30/0xd0
 shmem_evict_inode+0x2ec/0xa00
 evict+0x3f2/0x860
 iput+0x51c/0x830
 dentry_unlink_inode+0x2cd/0x4c0
 __dentry_kill+0x186/0x5b0
 dput.part.0+0x49e/0x990
 dput+0x1f/0x30
 __fput+0x52b/0xb60
 task_work_run+0x173/0x280
 syscall_exit_to_user_mode+0x29e/0x2a0
 do_syscall_64+0xdc/0x250
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2da111ebdb
Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2f 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007f2da20839a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000000000000597f RCX: 00007f2da111ebdb
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003
RBP: 00007f2da20846b0 R08: 0000000000000000 R09: 0000000000800000
R10: 0000000000000000 R11: 0000000000000293 R12: ffffffffffffffff
R13: 0000000000000016 R14: 0000000000000003 R15: 0000000020005bc0


thanks,
Kun Hu