2022-04-27 13:10:06

by syzbot

[permalink] [raw]
Subject: [syzbot] KASAN: use-after-free Read in mas_next_nentry

Hello,

syzbot found the following issue on:

HEAD commit: f02ac5c95dfd Add linux-next specific files for 20220427
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14bd8db2f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=e9256c70f586da8a
dashboard link: https://syzkaller.appspot.com/bug?extid=7170d66493145b71afd4
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=113b4252f00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1174bcbaf00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

==================================================================
BUG: KASAN: use-after-free in mas_safe_min lib/maple_tree.c:715 [inline]
BUG: KASAN: use-after-free in mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
Read of size 8 at addr ffff88807811e418 by task syz-executor361/3593

CPU: 1 PID: 3593 Comm: syz-executor361 Not tainted 5.18.0-rc4-next-20220427-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313
print_report mm/kasan/report.c:429 [inline]
kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
mas_safe_min lib/maple_tree.c:715 [inline]
mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
mas_next_entry lib/maple_tree.c:4636 [inline]
mas_next+0x1eb/0xc40 lib/maple_tree.c:5723
userfaultfd_register fs/userfaultfd.c:1468 [inline]
userfaultfd_ioctl+0x2527/0x40f0 fs/userfaultfd.c:1993
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f4e5785d939
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff7501a18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000031 RCX: 00007f4e5785d939
RDX: 00000000200001c0 RSI: 00000000c020aa00 RDI: 0000000000000003
RBP: 00007ffff7501b10 R08: 00007ffff7501a72 R09: 00007ffff7501a72
R10: 00007ffff7501a72 R11: 0000000000000246 R12: 00007ffff7501ae0
R13: 00007f4e578e14e0 R14: 0000000000000003 R15: 00007ffff7501a72
</TASK>

Allocated by task 3592:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
__kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
kasan_slab_alloc include/linux/kasan.h:224 [inline]
slab_post_alloc_hook mm/slab.h:750 [inline]
kmem_cache_alloc_bulk+0x39f/0x720 mm/slub.c:3728
mt_alloc_bulk lib/maple_tree.c:151 [inline]
mas_alloc_nodes+0x1df/0x6b0 lib/maple_tree.c:1244
mas_node_count+0x101/0x130 lib/maple_tree.c:1303
mas_split lib/maple_tree.c:3406 [inline]
mas_commit_b_node lib/maple_tree.c:3508 [inline]
mas_wr_modify+0x2505/0x5ac0 lib/maple_tree.c:4251
mas_wr_store_entry.isra.0+0x66e/0x10f0 lib/maple_tree.c:4289
mas_store+0xac/0xf0 lib/maple_tree.c:5523
dup_mmap+0x845/0x1030 kernel/fork.c:687
dup_mm+0x91/0x370 kernel/fork.c:1516
copy_mm kernel/fork.c:1565 [inline]
copy_process+0x3b07/0x6fd0 kernel/fork.c:2226
kernel_clone+0xe7/0xab0 kernel/fork.c:2631
__do_sys_clone+0xc8/0x110 kernel/fork.c:2748
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 3593:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:200 [inline]
slab_free_hook mm/slub.c:1727 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753
slab_free mm/slub.c:3507 [inline]
kmem_cache_free_bulk mm/slub.c:3654 [inline]
kmem_cache_free_bulk+0x2c0/0xb60 mm/slub.c:3641
mt_free_bulk lib/maple_tree.c:157 [inline]
mas_destroy+0x394/0x5c0 lib/maple_tree.c:5685
mas_store_prealloc+0xec/0x150 lib/maple_tree.c:5567
vma_mas_store mm/internal.h:482 [inline]
__vma_adjust+0x6ba/0x18f0 mm/mmap.c:811
vma_adjust include/linux/mm.h:2654 [inline]
__split_vma+0x443/0x530 mm/mmap.c:2259
split_vma+0x9f/0xe0 mm/mmap.c:2292
userfaultfd_register fs/userfaultfd.c:1444 [inline]
userfaultfd_ioctl+0x39f4/0x40f0 fs/userfaultfd.c:1993
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff88807811e400
which belongs to the cache maple_node of size 256
The buggy address is located 24 bytes inside of
256-byte region [ffff88807811e400, ffff88807811e500)

The buggy address belongs to the physical page:
page:ffffea0001e04780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7811e
head:ffffea0001e04780 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888010c4fdc0
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3286, tgid 3286 (dhcpcd-run-hook), ts 27966983290, free_ts 22717162691
prep_new_page mm/page_alloc.c:2431 [inline]
get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4172
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5393
alloc_pages+0x1aa/0x310 mm/mempolicy.c:2281
alloc_slab_page mm/slub.c:1797 [inline]
allocate_slab+0x26c/0x3c0 mm/slub.c:1942
new_slab mm/slub.c:2002 [inline]
___slab_alloc+0x985/0xd90 mm/slub.c:3002
kmem_cache_alloc_bulk+0x21c/0x720 mm/slub.c:3704
mt_alloc_bulk lib/maple_tree.c:151 [inline]
mas_alloc_nodes+0x2b0/0x6b0 lib/maple_tree.c:1244
mas_preallocate+0xfb/0x270 lib/maple_tree.c:5581
__vma_adjust+0x226/0x18f0 mm/mmap.c:742
vma_adjust include/linux/mm.h:2654 [inline]
__split_vma+0x443/0x530 mm/mmap.c:2259
do_mas_align_munmap+0x4f5/0xe80 mm/mmap.c:2375
do_mas_munmap+0x202/0x2c0 mm/mmap.c:2499
mmap_region+0x219/0x1c70 mm/mmap.c:2547
do_mmap+0x825/0xf60 mm/mmap.c:1471
vm_mmap_pgoff+0x1b7/0x290 mm/util.c:488
ksys_mmap_pgoff+0x40d/0x5a0 mm/mmap.c:1517
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1346 [inline]
free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1396
free_unref_page_prepare mm/page_alloc.c:3318 [inline]
free_unref_page+0x19/0x6a0 mm/page_alloc.c:3413
__unfreeze_partials+0x17c/0x1a0 mm/slub.c:2521
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
kasan_slab_alloc include/linux/kasan.h:224 [inline]
slab_post_alloc_hook mm/slab.h:750 [inline]
slab_alloc_node mm/slub.c:3214 [inline]
slab_alloc mm/slub.c:3222 [inline]
__kmalloc+0x200/0x350 mm/slub.c:4415
kmalloc include/linux/slab.h:593 [inline]
tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254
tomoyo_realpath_nofollow+0xc8/0xe0 security/tomoyo/realpath.c:309
tomoyo_find_next_domain+0x280/0x1f80 security/tomoyo/domain.c:727
tomoyo_bprm_check_security security/tomoyo/tomoyo.c:101 [inline]
tomoyo_bprm_check_security+0x121/0x1a0 security/tomoyo/tomoyo.c:91
security_bprm_check+0x45/0xa0 security/security.c:865
search_binary_handler fs/exec.c:1718 [inline]
exec_binprm fs/exec.c:1771 [inline]
bprm_execve fs/exec.c:1840 [inline]
bprm_execve+0x732/0x1970 fs/exec.c:1802
do_execveat_common+0x727/0x890 fs/exec.c:1945
do_execve fs/exec.c:2015 [inline]
__do_sys_execve fs/exec.c:2091 [inline]
__se_sys_execve fs/exec.c:2086 [inline]
__x64_sys_execve+0x8f/0xc0 fs/exec.c:2086
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80

Memory state around the buggy address:
ffff88807811e300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807811e380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807811e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807811e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807811e500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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2022-04-27 13:24:53

by Christian Brauner

[permalink] [raw]
Subject: Re: [syzbot] KASAN: use-after-free Read in mas_next_nentry

[+Cc Willy]

On Wed, Apr 27, 2022 at 05:43:22AM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: f02ac5c95dfd Add linux-next specific files for 20220427
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=14bd8db2f00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=e9256c70f586da8a
> dashboard link: https://syzkaller.appspot.com/bug?extid=7170d66493145b71afd4
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=113b4252f00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1174bcbaf00000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> ==================================================================
> BUG: KASAN: use-after-free in mas_safe_min lib/maple_tree.c:715 [inline]
> BUG: KASAN: use-after-free in mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
> Read of size 8 at addr ffff88807811e418 by task syz-executor361/3593
>
> CPU: 1 PID: 3593 Comm: syz-executor361 Not tainted 5.18.0-rc4-next-20220427-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313
> print_report mm/kasan/report.c:429 [inline]
> kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
> mas_safe_min lib/maple_tree.c:715 [inline]
> mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
> mas_next_entry lib/maple_tree.c:4636 [inline]
> mas_next+0x1eb/0xc40 lib/maple_tree.c:5723
> userfaultfd_register fs/userfaultfd.c:1468 [inline]
> userfaultfd_ioctl+0x2527/0x40f0 fs/userfaultfd.c:1993
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:870 [inline]
> __se_sys_ioctl fs/ioctl.c:856 [inline]
> __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7f4e5785d939
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffff7501a18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 0000000000000031 RCX: 00007f4e5785d939
> RDX: 00000000200001c0 RSI: 00000000c020aa00 RDI: 0000000000000003
> RBP: 00007ffff7501b10 R08: 00007ffff7501a72 R09: 00007ffff7501a72
> R10: 00007ffff7501a72 R11: 0000000000000246 R12: 00007ffff7501ae0
> R13: 00007f4e578e14e0 R14: 0000000000000003 R15: 00007ffff7501a72
> </TASK>
>
> Allocated by task 3592:
> kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> kasan_set_track mm/kasan/common.c:45 [inline]
> set_alloc_info mm/kasan/common.c:436 [inline]
> __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
> kasan_slab_alloc include/linux/kasan.h:224 [inline]
> slab_post_alloc_hook mm/slab.h:750 [inline]
> kmem_cache_alloc_bulk+0x39f/0x720 mm/slub.c:3728
> mt_alloc_bulk lib/maple_tree.c:151 [inline]
> mas_alloc_nodes+0x1df/0x6b0 lib/maple_tree.c:1244
> mas_node_count+0x101/0x130 lib/maple_tree.c:1303
> mas_split lib/maple_tree.c:3406 [inline]
> mas_commit_b_node lib/maple_tree.c:3508 [inline]
> mas_wr_modify+0x2505/0x5ac0 lib/maple_tree.c:4251
> mas_wr_store_entry.isra.0+0x66e/0x10f0 lib/maple_tree.c:4289
> mas_store+0xac/0xf0 lib/maple_tree.c:5523
> dup_mmap+0x845/0x1030 kernel/fork.c:687
> dup_mm+0x91/0x370 kernel/fork.c:1516
> copy_mm kernel/fork.c:1565 [inline]
> copy_process+0x3b07/0x6fd0 kernel/fork.c:2226
> kernel_clone+0xe7/0xab0 kernel/fork.c:2631
> __do_sys_clone+0xc8/0x110 kernel/fork.c:2748
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Freed by task 3593:
> kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> kasan_set_track+0x21/0x30 mm/kasan/common.c:45
> kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
> ____kasan_slab_free mm/kasan/common.c:366 [inline]
> ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328
> kasan_slab_free include/linux/kasan.h:200 [inline]
> slab_free_hook mm/slub.c:1727 [inline]
> slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753
> slab_free mm/slub.c:3507 [inline]
> kmem_cache_free_bulk mm/slub.c:3654 [inline]
> kmem_cache_free_bulk+0x2c0/0xb60 mm/slub.c:3641
> mt_free_bulk lib/maple_tree.c:157 [inline]
> mas_destroy+0x394/0x5c0 lib/maple_tree.c:5685
> mas_store_prealloc+0xec/0x150 lib/maple_tree.c:5567
> vma_mas_store mm/internal.h:482 [inline]
> __vma_adjust+0x6ba/0x18f0 mm/mmap.c:811
> vma_adjust include/linux/mm.h:2654 [inline]
> __split_vma+0x443/0x530 mm/mmap.c:2259
> split_vma+0x9f/0xe0 mm/mmap.c:2292
> userfaultfd_register fs/userfaultfd.c:1444 [inline]
> userfaultfd_ioctl+0x39f4/0x40f0 fs/userfaultfd.c:1993
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:870 [inline]
> __se_sys_ioctl fs/ioctl.c:856 [inline]
> __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> The buggy address belongs to the object at ffff88807811e400
> which belongs to the cache maple_node of size 256
> The buggy address is located 24 bytes inside of
> 256-byte region [ffff88807811e400, ffff88807811e500)
>
> The buggy address belongs to the physical page:
> page:ffffea0001e04780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7811e
> head:ffffea0001e04780 order:1 compound_mapcount:0 compound_pincount:0
> flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888010c4fdc0
> raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3286, tgid 3286 (dhcpcd-run-hook), ts 27966983290, free_ts 22717162691
> prep_new_page mm/page_alloc.c:2431 [inline]
> get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4172
> __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5393
> alloc_pages+0x1aa/0x310 mm/mempolicy.c:2281
> alloc_slab_page mm/slub.c:1797 [inline]
> allocate_slab+0x26c/0x3c0 mm/slub.c:1942
> new_slab mm/slub.c:2002 [inline]
> ___slab_alloc+0x985/0xd90 mm/slub.c:3002
> kmem_cache_alloc_bulk+0x21c/0x720 mm/slub.c:3704
> mt_alloc_bulk lib/maple_tree.c:151 [inline]
> mas_alloc_nodes+0x2b0/0x6b0 lib/maple_tree.c:1244
> mas_preallocate+0xfb/0x270 lib/maple_tree.c:5581
> __vma_adjust+0x226/0x18f0 mm/mmap.c:742
> vma_adjust include/linux/mm.h:2654 [inline]
> __split_vma+0x443/0x530 mm/mmap.c:2259
> do_mas_align_munmap+0x4f5/0xe80 mm/mmap.c:2375
> do_mas_munmap+0x202/0x2c0 mm/mmap.c:2499
> mmap_region+0x219/0x1c70 mm/mmap.c:2547
> do_mmap+0x825/0xf60 mm/mmap.c:1471
> vm_mmap_pgoff+0x1b7/0x290 mm/util.c:488
> ksys_mmap_pgoff+0x40d/0x5a0 mm/mmap.c:1517
> page last free stack trace:
> reset_page_owner include/linux/page_owner.h:24 [inline]
> free_pages_prepare mm/page_alloc.c:1346 [inline]
> free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1396
> free_unref_page_prepare mm/page_alloc.c:3318 [inline]
> free_unref_page+0x19/0x6a0 mm/page_alloc.c:3413
> __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2521
> qlink_free mm/kasan/quarantine.c:168 [inline]
> qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
> kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
> __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
> kasan_slab_alloc include/linux/kasan.h:224 [inline]
> slab_post_alloc_hook mm/slab.h:750 [inline]
> slab_alloc_node mm/slub.c:3214 [inline]
> slab_alloc mm/slub.c:3222 [inline]
> __kmalloc+0x200/0x350 mm/slub.c:4415
> kmalloc include/linux/slab.h:593 [inline]
> tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254
> tomoyo_realpath_nofollow+0xc8/0xe0 security/tomoyo/realpath.c:309
> tomoyo_find_next_domain+0x280/0x1f80 security/tomoyo/domain.c:727
> tomoyo_bprm_check_security security/tomoyo/tomoyo.c:101 [inline]
> tomoyo_bprm_check_security+0x121/0x1a0 security/tomoyo/tomoyo.c:91
> security_bprm_check+0x45/0xa0 security/security.c:865
> search_binary_handler fs/exec.c:1718 [inline]
> exec_binprm fs/exec.c:1771 [inline]
> bprm_execve fs/exec.c:1840 [inline]
> bprm_execve+0x732/0x1970 fs/exec.c:1802
> do_execveat_common+0x727/0x890 fs/exec.c:1945
> do_execve fs/exec.c:2015 [inline]
> __do_sys_execve fs/exec.c:2091 [inline]
> __se_sys_execve fs/exec.c:2086 [inline]
> __x64_sys_execve+0x8f/0xc0 fs/exec.c:2086
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>
> Memory state around the buggy address:
> ffff88807811e300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff88807811e380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >ffff88807811e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ^
> ffff88807811e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff88807811e500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at [email protected].
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches

2022-04-27 15:26:56

by Matthew Wilcox

[permalink] [raw]
Subject: Re: [syzbot] KASAN: use-after-free Read in mas_next_nentry

On Wed, Apr 27, 2022 at 02:55:58PM +0200, Christian Brauner wrote:
> [+Cc Willy]

I read fsdevel. Not sure Liam does though.

> On Wed, Apr 27, 2022 at 05:43:22AM -0700, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: f02ac5c95dfd Add linux-next specific files for 20220427
> > git tree: linux-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=14bd8db2f00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=e9256c70f586da8a
> > dashboard link: https://syzkaller.appspot.com/bug?extid=7170d66493145b71afd4
> > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=113b4252f00000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1174bcbaf00000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: [email protected]
> >
> > ==================================================================
> > BUG: KASAN: use-after-free in mas_safe_min lib/maple_tree.c:715 [inline]
> > BUG: KASAN: use-after-free in mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
> > Read of size 8 at addr ffff88807811e418 by task syz-executor361/3593
> >
> > CPU: 1 PID: 3593 Comm: syz-executor361 Not tainted 5.18.0-rc4-next-20220427-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > Call Trace:
> > <TASK>
> > __dump_stack lib/dump_stack.c:88 [inline]
> > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> > print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313
> > print_report mm/kasan/report.c:429 [inline]
> > kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
> > mas_safe_min lib/maple_tree.c:715 [inline]
> > mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
> > mas_next_entry lib/maple_tree.c:4636 [inline]
> > mas_next+0x1eb/0xc40 lib/maple_tree.c:5723
> > userfaultfd_register fs/userfaultfd.c:1468 [inline]
> > userfaultfd_ioctl+0x2527/0x40f0 fs/userfaultfd.c:1993
> > vfs_ioctl fs/ioctl.c:51 [inline]
> > __do_sys_ioctl fs/ioctl.c:870 [inline]
> > __se_sys_ioctl fs/ioctl.c:856 [inline]
> > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > RIP: 0033:0x7f4e5785d939
> > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007ffff7501a18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > RAX: ffffffffffffffda RBX: 0000000000000031 RCX: 00007f4e5785d939
> > RDX: 00000000200001c0 RSI: 00000000c020aa00 RDI: 0000000000000003
> > RBP: 00007ffff7501b10 R08: 00007ffff7501a72 R09: 00007ffff7501a72
> > R10: 00007ffff7501a72 R11: 0000000000000246 R12: 00007ffff7501ae0
> > R13: 00007f4e578e14e0 R14: 0000000000000003 R15: 00007ffff7501a72
> > </TASK>
> >
> > Allocated by task 3592:
> > kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> > kasan_set_track mm/kasan/common.c:45 [inline]
> > set_alloc_info mm/kasan/common.c:436 [inline]
> > __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
> > kasan_slab_alloc include/linux/kasan.h:224 [inline]
> > slab_post_alloc_hook mm/slab.h:750 [inline]
> > kmem_cache_alloc_bulk+0x39f/0x720 mm/slub.c:3728
> > mt_alloc_bulk lib/maple_tree.c:151 [inline]
> > mas_alloc_nodes+0x1df/0x6b0 lib/maple_tree.c:1244
> > mas_node_count+0x101/0x130 lib/maple_tree.c:1303
> > mas_split lib/maple_tree.c:3406 [inline]
> > mas_commit_b_node lib/maple_tree.c:3508 [inline]
> > mas_wr_modify+0x2505/0x5ac0 lib/maple_tree.c:4251
> > mas_wr_store_entry.isra.0+0x66e/0x10f0 lib/maple_tree.c:4289
> > mas_store+0xac/0xf0 lib/maple_tree.c:5523
> > dup_mmap+0x845/0x1030 kernel/fork.c:687
> > dup_mm+0x91/0x370 kernel/fork.c:1516
> > copy_mm kernel/fork.c:1565 [inline]
> > copy_process+0x3b07/0x6fd0 kernel/fork.c:2226
> > kernel_clone+0xe7/0xab0 kernel/fork.c:2631
> > __do_sys_clone+0xc8/0x110 kernel/fork.c:2748
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > Freed by task 3593:
> > kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> > kasan_set_track+0x21/0x30 mm/kasan/common.c:45
> > kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
> > ____kasan_slab_free mm/kasan/common.c:366 [inline]
> > ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328
> > kasan_slab_free include/linux/kasan.h:200 [inline]
> > slab_free_hook mm/slub.c:1727 [inline]
> > slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753
> > slab_free mm/slub.c:3507 [inline]
> > kmem_cache_free_bulk mm/slub.c:3654 [inline]
> > kmem_cache_free_bulk+0x2c0/0xb60 mm/slub.c:3641
> > mt_free_bulk lib/maple_tree.c:157 [inline]
> > mas_destroy+0x394/0x5c0 lib/maple_tree.c:5685
> > mas_store_prealloc+0xec/0x150 lib/maple_tree.c:5567
> > vma_mas_store mm/internal.h:482 [inline]
> > __vma_adjust+0x6ba/0x18f0 mm/mmap.c:811
> > vma_adjust include/linux/mm.h:2654 [inline]
> > __split_vma+0x443/0x530 mm/mmap.c:2259
> > split_vma+0x9f/0xe0 mm/mmap.c:2292
> > userfaultfd_register fs/userfaultfd.c:1444 [inline]
> > userfaultfd_ioctl+0x39f4/0x40f0 fs/userfaultfd.c:1993
> > vfs_ioctl fs/ioctl.c:51 [inline]
> > __do_sys_ioctl fs/ioctl.c:870 [inline]
> > __se_sys_ioctl fs/ioctl.c:856 [inline]
> > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > The buggy address belongs to the object at ffff88807811e400
> > which belongs to the cache maple_node of size 256
> > The buggy address is located 24 bytes inside of
> > 256-byte region [ffff88807811e400, ffff88807811e500)
> >
> > The buggy address belongs to the physical page:
> > page:ffffea0001e04780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7811e
> > head:ffffea0001e04780 order:1 compound_mapcount:0 compound_pincount:0
> > flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> > raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888010c4fdc0
> > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
> > page dumped because: kasan: bad access detected
> > page_owner tracks the page as allocated
> > page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3286, tgid 3286 (dhcpcd-run-hook), ts 27966983290, free_ts 22717162691
> > prep_new_page mm/page_alloc.c:2431 [inline]
> > get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4172
> > __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5393
> > alloc_pages+0x1aa/0x310 mm/mempolicy.c:2281
> > alloc_slab_page mm/slub.c:1797 [inline]
> > allocate_slab+0x26c/0x3c0 mm/slub.c:1942
> > new_slab mm/slub.c:2002 [inline]
> > ___slab_alloc+0x985/0xd90 mm/slub.c:3002
> > kmem_cache_alloc_bulk+0x21c/0x720 mm/slub.c:3704
> > mt_alloc_bulk lib/maple_tree.c:151 [inline]
> > mas_alloc_nodes+0x2b0/0x6b0 lib/maple_tree.c:1244
> > mas_preallocate+0xfb/0x270 lib/maple_tree.c:5581
> > __vma_adjust+0x226/0x18f0 mm/mmap.c:742
> > vma_adjust include/linux/mm.h:2654 [inline]
> > __split_vma+0x443/0x530 mm/mmap.c:2259
> > do_mas_align_munmap+0x4f5/0xe80 mm/mmap.c:2375
> > do_mas_munmap+0x202/0x2c0 mm/mmap.c:2499
> > mmap_region+0x219/0x1c70 mm/mmap.c:2547
> > do_mmap+0x825/0xf60 mm/mmap.c:1471
> > vm_mmap_pgoff+0x1b7/0x290 mm/util.c:488
> > ksys_mmap_pgoff+0x40d/0x5a0 mm/mmap.c:1517
> > page last free stack trace:
> > reset_page_owner include/linux/page_owner.h:24 [inline]
> > free_pages_prepare mm/page_alloc.c:1346 [inline]
> > free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1396
> > free_unref_page_prepare mm/page_alloc.c:3318 [inline]
> > free_unref_page+0x19/0x6a0 mm/page_alloc.c:3413
> > __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2521
> > qlink_free mm/kasan/quarantine.c:168 [inline]
> > qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
> > kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
> > __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
> > kasan_slab_alloc include/linux/kasan.h:224 [inline]
> > slab_post_alloc_hook mm/slab.h:750 [inline]
> > slab_alloc_node mm/slub.c:3214 [inline]
> > slab_alloc mm/slub.c:3222 [inline]
> > __kmalloc+0x200/0x350 mm/slub.c:4415
> > kmalloc include/linux/slab.h:593 [inline]
> > tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254
> > tomoyo_realpath_nofollow+0xc8/0xe0 security/tomoyo/realpath.c:309
> > tomoyo_find_next_domain+0x280/0x1f80 security/tomoyo/domain.c:727
> > tomoyo_bprm_check_security security/tomoyo/tomoyo.c:101 [inline]
> > tomoyo_bprm_check_security+0x121/0x1a0 security/tomoyo/tomoyo.c:91
> > security_bprm_check+0x45/0xa0 security/security.c:865
> > search_binary_handler fs/exec.c:1718 [inline]
> > exec_binprm fs/exec.c:1771 [inline]
> > bprm_execve fs/exec.c:1840 [inline]
> > bprm_execve+0x732/0x1970 fs/exec.c:1802
> > do_execveat_common+0x727/0x890 fs/exec.c:1945
> > do_execve fs/exec.c:2015 [inline]
> > __do_sys_execve fs/exec.c:2091 [inline]
> > __se_sys_execve fs/exec.c:2086 [inline]
> > __x64_sys_execve+0x8f/0xc0 fs/exec.c:2086
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> >
> > Memory state around the buggy address:
> > ffff88807811e300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > ffff88807811e380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > >ffff88807811e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ^
> > ffff88807811e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ffff88807811e500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > ==================================================================
> >
> >
> > ---
> > This report is generated by a bot. It may contain errors.
> > See https://goo.gl/tpsmEJ for more information about syzbot.
> > syzbot engineers can be reached at [email protected].
> >
> > syzbot will keep track of this issue. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > syzbot can test patches for this issue, for details see:
> > https://goo.gl/tpsmEJ#testing-patches

2022-04-27 15:44:48

by Liam R. Howlett

[permalink] [raw]
Subject: Re: [syzbot] KASAN: use-after-free Read in mas_next_nentry

* Matthew Wilcox <[email protected]> [220427 10:58]:
> On Wed, Apr 27, 2022 at 02:55:58PM +0200, Christian Brauner wrote:
> > [+Cc Willy]
>
> I read fsdevel. Not sure Liam does though.

I do not. Thank you for sending it along.

Here is a patch that should fix the issue. I will ask AKPM to include
it for tomorrow.

>
> > On Wed, Apr 27, 2022 at 05:43:22AM -0700, syzbot wrote:
> > > Hello,
> > >
> > > syzbot found the following issue on:
> > >
> > > HEAD commit: f02ac5c95dfd Add linux-next specific files for 20220427
> > > git tree: linux-next
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=14bd8db2f00000
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=e9256c70f586da8a
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=7170d66493145b71afd4
> > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=113b4252f00000
> > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1174bcbaf00000
> > >
> > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > Reported-by: [email protected]
> > >
> > > ==================================================================
> > > BUG: KASAN: use-after-free in mas_safe_min lib/maple_tree.c:715 [inline]
> > > BUG: KASAN: use-after-free in mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
> > > Read of size 8 at addr ffff88807811e418 by task syz-executor361/3593
> > >
> > > CPU: 1 PID: 3593 Comm: syz-executor361 Not tainted 5.18.0-rc4-next-20220427-syzkaller #0
> > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > > Call Trace:
> > > <TASK>
> > > __dump_stack lib/dump_stack.c:88 [inline]
> > > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> > > print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313
> > > print_report mm/kasan/report.c:429 [inline]
> > > kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
> > > mas_safe_min lib/maple_tree.c:715 [inline]
> > > mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
> > > mas_next_entry lib/maple_tree.c:4636 [inline]
> > > mas_next+0x1eb/0xc40 lib/maple_tree.c:5723
> > > userfaultfd_register fs/userfaultfd.c:1468 [inline]
> > > userfaultfd_ioctl+0x2527/0x40f0 fs/userfaultfd.c:1993
> > > vfs_ioctl fs/ioctl.c:51 [inline]
> > > __do_sys_ioctl fs/ioctl.c:870 [inline]
> > > __se_sys_ioctl fs/ioctl.c:856 [inline]
> > > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
> > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > > RIP: 0033:0x7f4e5785d939
> > > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> > > RSP: 002b:00007ffff7501a18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > > RAX: ffffffffffffffda RBX: 0000000000000031 RCX: 00007f4e5785d939
> > > RDX: 00000000200001c0 RSI: 00000000c020aa00 RDI: 0000000000000003
> > > RBP: 00007ffff7501b10 R08: 00007ffff7501a72 R09: 00007ffff7501a72
> > > R10: 00007ffff7501a72 R11: 0000000000000246 R12: 00007ffff7501ae0
> > > R13: 00007f4e578e14e0 R14: 0000000000000003 R15: 00007ffff7501a72
> > > </TASK>
> > >
> > > Allocated by task 3592:
> > > kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> > > kasan_set_track mm/kasan/common.c:45 [inline]
> > > set_alloc_info mm/kasan/common.c:436 [inline]
> > > __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
> > > kasan_slab_alloc include/linux/kasan.h:224 [inline]
> > > slab_post_alloc_hook mm/slab.h:750 [inline]
> > > kmem_cache_alloc_bulk+0x39f/0x720 mm/slub.c:3728
> > > mt_alloc_bulk lib/maple_tree.c:151 [inline]
> > > mas_alloc_nodes+0x1df/0x6b0 lib/maple_tree.c:1244
> > > mas_node_count+0x101/0x130 lib/maple_tree.c:1303
> > > mas_split lib/maple_tree.c:3406 [inline]
> > > mas_commit_b_node lib/maple_tree.c:3508 [inline]
> > > mas_wr_modify+0x2505/0x5ac0 lib/maple_tree.c:4251
> > > mas_wr_store_entry.isra.0+0x66e/0x10f0 lib/maple_tree.c:4289
> > > mas_store+0xac/0xf0 lib/maple_tree.c:5523
> > > dup_mmap+0x845/0x1030 kernel/fork.c:687
> > > dup_mm+0x91/0x370 kernel/fork.c:1516
> > > copy_mm kernel/fork.c:1565 [inline]
> > > copy_process+0x3b07/0x6fd0 kernel/fork.c:2226
> > > kernel_clone+0xe7/0xab0 kernel/fork.c:2631
> > > __do_sys_clone+0xc8/0x110 kernel/fork.c:2748
> > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > >
> > > Freed by task 3593:
> > > kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> > > kasan_set_track+0x21/0x30 mm/kasan/common.c:45
> > > kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
> > > ____kasan_slab_free mm/kasan/common.c:366 [inline]
> > > ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328
> > > kasan_slab_free include/linux/kasan.h:200 [inline]
> > > slab_free_hook mm/slub.c:1727 [inline]
> > > slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753
> > > slab_free mm/slub.c:3507 [inline]
> > > kmem_cache_free_bulk mm/slub.c:3654 [inline]
> > > kmem_cache_free_bulk+0x2c0/0xb60 mm/slub.c:3641
> > > mt_free_bulk lib/maple_tree.c:157 [inline]
> > > mas_destroy+0x394/0x5c0 lib/maple_tree.c:5685
> > > mas_store_prealloc+0xec/0x150 lib/maple_tree.c:5567
> > > vma_mas_store mm/internal.h:482 [inline]
> > > __vma_adjust+0x6ba/0x18f0 mm/mmap.c:811
> > > vma_adjust include/linux/mm.h:2654 [inline]
> > > __split_vma+0x443/0x530 mm/mmap.c:2259
> > > split_vma+0x9f/0xe0 mm/mmap.c:2292
> > > userfaultfd_register fs/userfaultfd.c:1444 [inline]
> > > userfaultfd_ioctl+0x39f4/0x40f0 fs/userfaultfd.c:1993
> > > vfs_ioctl fs/ioctl.c:51 [inline]
> > > __do_sys_ioctl fs/ioctl.c:870 [inline]
> > > __se_sys_ioctl fs/ioctl.c:856 [inline]
> > > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
> > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > >
> > > The buggy address belongs to the object at ffff88807811e400
> > > which belongs to the cache maple_node of size 256
> > > The buggy address is located 24 bytes inside of
> > > 256-byte region [ffff88807811e400, ffff88807811e500)
> > >
> > > The buggy address belongs to the physical page:
> > > page:ffffea0001e04780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7811e
> > > head:ffffea0001e04780 order:1 compound_mapcount:0 compound_pincount:0
> > > flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> > > raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888010c4fdc0
> > > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
> > > page dumped because: kasan: bad access detected
> > > page_owner tracks the page as allocated
> > > page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3286, tgid 3286 (dhcpcd-run-hook), ts 27966983290, free_ts 22717162691
> > > prep_new_page mm/page_alloc.c:2431 [inline]
> > > get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4172
> > > __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5393
> > > alloc_pages+0x1aa/0x310 mm/mempolicy.c:2281
> > > alloc_slab_page mm/slub.c:1797 [inline]
> > > allocate_slab+0x26c/0x3c0 mm/slub.c:1942
> > > new_slab mm/slub.c:2002 [inline]
> > > ___slab_alloc+0x985/0xd90 mm/slub.c:3002
> > > kmem_cache_alloc_bulk+0x21c/0x720 mm/slub.c:3704
> > > mt_alloc_bulk lib/maple_tree.c:151 [inline]
> > > mas_alloc_nodes+0x2b0/0x6b0 lib/maple_tree.c:1244
> > > mas_preallocate+0xfb/0x270 lib/maple_tree.c:5581
> > > __vma_adjust+0x226/0x18f0 mm/mmap.c:742
> > > vma_adjust include/linux/mm.h:2654 [inline]
> > > __split_vma+0x443/0x530 mm/mmap.c:2259
> > > do_mas_align_munmap+0x4f5/0xe80 mm/mmap.c:2375
> > > do_mas_munmap+0x202/0x2c0 mm/mmap.c:2499
> > > mmap_region+0x219/0x1c70 mm/mmap.c:2547
> > > do_mmap+0x825/0xf60 mm/mmap.c:1471
> > > vm_mmap_pgoff+0x1b7/0x290 mm/util.c:488
> > > ksys_mmap_pgoff+0x40d/0x5a0 mm/mmap.c:1517
> > > page last free stack trace:
> > > reset_page_owner include/linux/page_owner.h:24 [inline]
> > > free_pages_prepare mm/page_alloc.c:1346 [inline]
> > > free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1396
> > > free_unref_page_prepare mm/page_alloc.c:3318 [inline]
> > > free_unref_page+0x19/0x6a0 mm/page_alloc.c:3413
> > > __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2521
> > > qlink_free mm/kasan/quarantine.c:168 [inline]
> > > qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
> > > kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
> > > __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
> > > kasan_slab_alloc include/linux/kasan.h:224 [inline]
> > > slab_post_alloc_hook mm/slab.h:750 [inline]
> > > slab_alloc_node mm/slub.c:3214 [inline]
> > > slab_alloc mm/slub.c:3222 [inline]
> > > __kmalloc+0x200/0x350 mm/slub.c:4415
> > > kmalloc include/linux/slab.h:593 [inline]
> > > tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254
> > > tomoyo_realpath_nofollow+0xc8/0xe0 security/tomoyo/realpath.c:309
> > > tomoyo_find_next_domain+0x280/0x1f80 security/tomoyo/domain.c:727
> > > tomoyo_bprm_check_security security/tomoyo/tomoyo.c:101 [inline]
> > > tomoyo_bprm_check_security+0x121/0x1a0 security/tomoyo/tomoyo.c:91
> > > security_bprm_check+0x45/0xa0 security/security.c:865
> > > search_binary_handler fs/exec.c:1718 [inline]
> > > exec_binprm fs/exec.c:1771 [inline]
> > > bprm_execve fs/exec.c:1840 [inline]
> > > bprm_execve+0x732/0x1970 fs/exec.c:1802
> > > do_execveat_common+0x727/0x890 fs/exec.c:1945
> > > do_execve fs/exec.c:2015 [inline]
> > > __do_sys_execve fs/exec.c:2091 [inline]
> > > __se_sys_execve fs/exec.c:2086 [inline]
> > > __x64_sys_execve+0x8f/0xc0 fs/exec.c:2086
> > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > >
> > > Memory state around the buggy address:
> > > ffff88807811e300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > ffff88807811e380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > >ffff88807811e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > > ^
> > > ffff88807811e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > > ffff88807811e500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > ==================================================================
> > >
> > >
> > > ---
> > > This report is generated by a bot. It may contain errors.
> > > See https://goo.gl/tpsmEJ for more information about syzbot.
> > > syzbot engineers can be reached at [email protected].
> > >
> > > syzbot will keep track of this issue. See:
> > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > > syzbot can test patches for this issue, for details see:
> > > https://goo.gl/tpsmEJ#testing-patches


Attachments:
0001-fs-userfaultfd-Fix-maple-state-in-userfaultfd_regist.patch (1.30 kB)
0001-fs-userfaultfd-Fix-maple-state-in-userfaultfd_regist.patch

2022-04-27 15:49:33

by Dmitry Vyukov

[permalink] [raw]
Subject: Re: [syzbot] KASAN: use-after-free Read in mas_next_nentry

On Wed, 27 Apr 2022 at 17:17, Liam Howlett <[email protected]> wrote:
>
> * Matthew Wilcox <[email protected]> [220427 10:58]:
> > On Wed, Apr 27, 2022 at 02:55:58PM +0200, Christian Brauner wrote:
> > > [+Cc Willy]
> >
> > I read fsdevel. Not sure Liam does though.
>
> I do not. Thank you for sending it along.
>
> Here is a patch that should fix the issue. I will ask AKPM to include
> it for tomorrow.

Please add the reported tag:

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

> > > On Wed, Apr 27, 2022 at 05:43:22AM -0700, syzbot wrote:
> > > > Hello,
> > > >
> > > > syzbot found the following issue on:
> > > >
> > > > HEAD commit: f02ac5c95dfd Add linux-next specific files for 20220427
> > > > git tree: linux-next
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=14bd8db2f00000
> > > > kernel config: https://syzkaller.appspot.com/x/.config?x=e9256c70f586da8a
> > > > dashboard link: https://syzkaller.appspot.com/bug?extid=7170d66493145b71afd4
> > > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=113b4252f00000
> > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1174bcbaf00000
> > > >
> > > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > > Reported-by: [email protected]
> > > >
> > > > ==================================================================
> > > > BUG: KASAN: use-after-free in mas_safe_min lib/maple_tree.c:715 [inline]
> > > > BUG: KASAN: use-after-free in mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
> > > > Read of size 8 at addr ffff88807811e418 by task syz-executor361/3593
> > > >
> > > > CPU: 1 PID: 3593 Comm: syz-executor361 Not tainted 5.18.0-rc4-next-20220427-syzkaller #0
> > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > > > Call Trace:
> > > > <TASK>
> > > > __dump_stack lib/dump_stack.c:88 [inline]
> > > > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> > > > print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313
> > > > print_report mm/kasan/report.c:429 [inline]
> > > > kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
> > > > mas_safe_min lib/maple_tree.c:715 [inline]
> > > > mas_next_nentry+0x997/0xaa0 lib/maple_tree.c:4546
> > > > mas_next_entry lib/maple_tree.c:4636 [inline]
> > > > mas_next+0x1eb/0xc40 lib/maple_tree.c:5723
> > > > userfaultfd_register fs/userfaultfd.c:1468 [inline]
> > > > userfaultfd_ioctl+0x2527/0x40f0 fs/userfaultfd.c:1993
> > > > vfs_ioctl fs/ioctl.c:51 [inline]
> > > > __do_sys_ioctl fs/ioctl.c:870 [inline]
> > > > __se_sys_ioctl fs/ioctl.c:856 [inline]
> > > > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
> > > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > > > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > > > RIP: 0033:0x7f4e5785d939
> > > > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> > > > RSP: 002b:00007ffff7501a18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > > > RAX: ffffffffffffffda RBX: 0000000000000031 RCX: 00007f4e5785d939
> > > > RDX: 00000000200001c0 RSI: 00000000c020aa00 RDI: 0000000000000003
> > > > RBP: 00007ffff7501b10 R08: 00007ffff7501a72 R09: 00007ffff7501a72
> > > > R10: 00007ffff7501a72 R11: 0000000000000246 R12: 00007ffff7501ae0
> > > > R13: 00007f4e578e14e0 R14: 0000000000000003 R15: 00007ffff7501a72
> > > > </TASK>
> > > >
> > > > Allocated by task 3592:
> > > > kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> > > > kasan_set_track mm/kasan/common.c:45 [inline]
> > > > set_alloc_info mm/kasan/common.c:436 [inline]
> > > > __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
> > > > kasan_slab_alloc include/linux/kasan.h:224 [inline]
> > > > slab_post_alloc_hook mm/slab.h:750 [inline]
> > > > kmem_cache_alloc_bulk+0x39f/0x720 mm/slub.c:3728
> > > > mt_alloc_bulk lib/maple_tree.c:151 [inline]
> > > > mas_alloc_nodes+0x1df/0x6b0 lib/maple_tree.c:1244
> > > > mas_node_count+0x101/0x130 lib/maple_tree.c:1303
> > > > mas_split lib/maple_tree.c:3406 [inline]
> > > > mas_commit_b_node lib/maple_tree.c:3508 [inline]
> > > > mas_wr_modify+0x2505/0x5ac0 lib/maple_tree.c:4251
> > > > mas_wr_store_entry.isra.0+0x66e/0x10f0 lib/maple_tree.c:4289
> > > > mas_store+0xac/0xf0 lib/maple_tree.c:5523
> > > > dup_mmap+0x845/0x1030 kernel/fork.c:687
> > > > dup_mm+0x91/0x370 kernel/fork.c:1516
> > > > copy_mm kernel/fork.c:1565 [inline]
> > > > copy_process+0x3b07/0x6fd0 kernel/fork.c:2226
> > > > kernel_clone+0xe7/0xab0 kernel/fork.c:2631
> > > > __do_sys_clone+0xc8/0x110 kernel/fork.c:2748
> > > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > > > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > > >
> > > > Freed by task 3593:
> > > > kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> > > > kasan_set_track+0x21/0x30 mm/kasan/common.c:45
> > > > kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
> > > > ____kasan_slab_free mm/kasan/common.c:366 [inline]
> > > > ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328
> > > > kasan_slab_free include/linux/kasan.h:200 [inline]
> > > > slab_free_hook mm/slub.c:1727 [inline]
> > > > slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753
> > > > slab_free mm/slub.c:3507 [inline]
> > > > kmem_cache_free_bulk mm/slub.c:3654 [inline]
> > > > kmem_cache_free_bulk+0x2c0/0xb60 mm/slub.c:3641
> > > > mt_free_bulk lib/maple_tree.c:157 [inline]
> > > > mas_destroy+0x394/0x5c0 lib/maple_tree.c:5685
> > > > mas_store_prealloc+0xec/0x150 lib/maple_tree.c:5567
> > > > vma_mas_store mm/internal.h:482 [inline]
> > > > __vma_adjust+0x6ba/0x18f0 mm/mmap.c:811
> > > > vma_adjust include/linux/mm.h:2654 [inline]
> > > > __split_vma+0x443/0x530 mm/mmap.c:2259
> > > > split_vma+0x9f/0xe0 mm/mmap.c:2292
> > > > userfaultfd_register fs/userfaultfd.c:1444 [inline]
> > > > userfaultfd_ioctl+0x39f4/0x40f0 fs/userfaultfd.c:1993
> > > > vfs_ioctl fs/ioctl.c:51 [inline]
> > > > __do_sys_ioctl fs/ioctl.c:870 [inline]
> > > > __se_sys_ioctl fs/ioctl.c:856 [inline]
> > > > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
> > > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > > > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > > >
> > > > The buggy address belongs to the object at ffff88807811e400
> > > > which belongs to the cache maple_node of size 256
> > > > The buggy address is located 24 bytes inside of
> > > > 256-byte region [ffff88807811e400, ffff88807811e500)
> > > >
> > > > The buggy address belongs to the physical page:
> > > > page:ffffea0001e04780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7811e
> > > > head:ffffea0001e04780 order:1 compound_mapcount:0 compound_pincount:0
> > > > flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> > > > raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888010c4fdc0
> > > > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
> > > > page dumped because: kasan: bad access detected
> > > > page_owner tracks the page as allocated
> > > > page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3286, tgid 3286 (dhcpcd-run-hook), ts 27966983290, free_ts 22717162691
> > > > prep_new_page mm/page_alloc.c:2431 [inline]
> > > > get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4172
> > > > __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5393
> > > > alloc_pages+0x1aa/0x310 mm/mempolicy.c:2281
> > > > alloc_slab_page mm/slub.c:1797 [inline]
> > > > allocate_slab+0x26c/0x3c0 mm/slub.c:1942
> > > > new_slab mm/slub.c:2002 [inline]
> > > > ___slab_alloc+0x985/0xd90 mm/slub.c:3002
> > > > kmem_cache_alloc_bulk+0x21c/0x720 mm/slub.c:3704
> > > > mt_alloc_bulk lib/maple_tree.c:151 [inline]
> > > > mas_alloc_nodes+0x2b0/0x6b0 lib/maple_tree.c:1244
> > > > mas_preallocate+0xfb/0x270 lib/maple_tree.c:5581
> > > > __vma_adjust+0x226/0x18f0 mm/mmap.c:742
> > > > vma_adjust include/linux/mm.h:2654 [inline]
> > > > __split_vma+0x443/0x530 mm/mmap.c:2259
> > > > do_mas_align_munmap+0x4f5/0xe80 mm/mmap.c:2375
> > > > do_mas_munmap+0x202/0x2c0 mm/mmap.c:2499
> > > > mmap_region+0x219/0x1c70 mm/mmap.c:2547
> > > > do_mmap+0x825/0xf60 mm/mmap.c:1471
> > > > vm_mmap_pgoff+0x1b7/0x290 mm/util.c:488
> > > > ksys_mmap_pgoff+0x40d/0x5a0 mm/mmap.c:1517
> > > > page last free stack trace:
> > > > reset_page_owner include/linux/page_owner.h:24 [inline]
> > > > free_pages_prepare mm/page_alloc.c:1346 [inline]
> > > > free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1396
> > > > free_unref_page_prepare mm/page_alloc.c:3318 [inline]
> > > > free_unref_page+0x19/0x6a0 mm/page_alloc.c:3413
> > > > __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2521
> > > > qlink_free mm/kasan/quarantine.c:168 [inline]
> > > > qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
> > > > kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
> > > > __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
> > > > kasan_slab_alloc include/linux/kasan.h:224 [inline]
> > > > slab_post_alloc_hook mm/slab.h:750 [inline]
> > > > slab_alloc_node mm/slub.c:3214 [inline]
> > > > slab_alloc mm/slub.c:3222 [inline]
> > > > __kmalloc+0x200/0x350 mm/slub.c:4415
> > > > kmalloc include/linux/slab.h:593 [inline]
> > > > tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254
> > > > tomoyo_realpath_nofollow+0xc8/0xe0 security/tomoyo/realpath.c:309
> > > > tomoyo_find_next_domain+0x280/0x1f80 security/tomoyo/domain.c:727
> > > > tomoyo_bprm_check_security security/tomoyo/tomoyo.c:101 [inline]
> > > > tomoyo_bprm_check_security+0x121/0x1a0 security/tomoyo/tomoyo.c:91
> > > > security_bprm_check+0x45/0xa0 security/security.c:865
> > > > search_binary_handler fs/exec.c:1718 [inline]
> > > > exec_binprm fs/exec.c:1771 [inline]
> > > > bprm_execve fs/exec.c:1840 [inline]
> > > > bprm_execve+0x732/0x1970 fs/exec.c:1802
> > > > do_execveat_common+0x727/0x890 fs/exec.c:1945
> > > > do_execve fs/exec.c:2015 [inline]
> > > > __do_sys_execve fs/exec.c:2091 [inline]
> > > > __se_sys_execve fs/exec.c:2086 [inline]
> > > > __x64_sys_execve+0x8f/0xc0 fs/exec.c:2086
> > > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > > >
> > > > Memory state around the buggy address:
> > > > ffff88807811e300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > > ffff88807811e380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > > >ffff88807811e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > > > ^
> > > > ffff88807811e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > > > ffff88807811e500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > > ==================================================================
> > > >
> > > >
> > > > ---
> > > > This report is generated by a bot. It may contain errors.
> > > > See https://goo.gl/tpsmEJ for more information about syzbot.
> > > > syzbot engineers can be reached at [email protected].
> > > >
> > > > syzbot will keep track of this issue. See:
> > > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > > > syzbot can test patches for this issue, for details see:
> > > > https://goo.gl/tpsmEJ#testing-patches
>
> --
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2022-04-28 08:29:50

by Dan Carpenter

[permalink] [raw]
Subject: Re: [syzbot] KASAN: use-after-free Read in mas_next_nentry

On Wed, Apr 27, 2022 at 05:22:31PM +0200, 'Dmitry Vyukov' via syzkaller-bugs wrote:
> On Wed, 27 Apr 2022 at 17:17, Liam Howlett <[email protected]> wrote:
> >
> > * Matthew Wilcox <[email protected]> [220427 10:58]:
> > > On Wed, Apr 27, 2022 at 02:55:58PM +0200, Christian Brauner wrote:
> > > > [+Cc Willy]
> > >
> > > I read fsdevel. Not sure Liam does though.
> >
> > I do not. Thank you for sending it along.
> >
> > Here is a patch that should fix the issue. I will ask AKPM to include
> > it for tomorrow.
>
> Please add the reported tag:
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>

And a Fixes tag as well.

regards,
dan carpenter

2023-01-25 22:04:23

by syzbot

[permalink] [raw]
Subject: Re: [syzbot] KASAN: use-after-free Read in mas_next_nentry

syzbot suspects this issue was fixed by commit:

commit 59f2f4b8a757412fce372f6d0767bdb55da127a8
Author: Liam Howlett <[email protected]>
Date: Mon Nov 7 20:11:42 2022 +0000

fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=129e8afe480000
start commit: b229b6ca5abb Merge tag 'perf-tools-fixes-for-v6.1-2022-10-..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=a66c6c673fb555e8
dashboard link: https://syzkaller.appspot.com/bug?extid=7170d66493145b71afd4
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11bfb2a9880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10b1d319880000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

2023-01-26 13:15:41

by Liam R. Howlett

[permalink] [raw]
Subject: Re: [syzbot] KASAN: use-after-free Read in mas_next_nentry

syz fix: fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()

* syzbot <[email protected]> [230125 17:04]:
> syzbot suspects this issue was fixed by commit:
>
> commit 59f2f4b8a757412fce372f6d0767bdb55da127a8
> Author: Liam Howlett <[email protected]>
> Date: Mon Nov 7 20:11:42 2022 +0000
>
> fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=129e8afe480000
> start commit: b229b6ca5abb Merge tag 'perf-tools-fixes-for-v6.1-2022-10-..
> git tree: upstream
> kernel config: https://syzkaller.appspot.com/x/.config?x=a66c6c673fb555e8
> dashboard link: https://syzkaller.appspot.com/bug?extid=7170d66493145b71afd4
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11bfb2a9880000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10b1d319880000
>
> If the result looks correct, please mark the issue as fixed by replying with:
>
> #syz fix: fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection

2023-01-27 07:09:26

by Dmitry Vyukov

[permalink] [raw]
Subject: Re: [syzbot] KASAN: use-after-free Read in mas_next_nentry

On Thu, 26 Jan 2023 at 14:14, Liam R. Howlett <[email protected]> wrote:
>
> syz fix: fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()
>
> * syzbot <[email protected]> [230125 17:04]:
> > syzbot suspects this issue was fixed by commit:

syzbot needs the hash to parse the command:

#syz fix: fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()

> > commit 59f2f4b8a757412fce372f6d0767bdb55da127a8
> > Author: Liam Howlett <[email protected]>
> > Date: Mon Nov 7 20:11:42 2022 +0000
> >
> > fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()
> >
> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=129e8afe480000
> > start commit: b229b6ca5abb Merge tag 'perf-tools-fixes-for-v6.1-2022-10-..
> > git tree: upstream
> > kernel config: https://syzkaller.appspot.com/x/.config?x=a66c6c673fb555e8
> > dashboard link: https://syzkaller.appspot.com/bug?extid=7170d66493145b71afd4
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11bfb2a9880000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10b1d319880000
> >
> > If the result looks correct, please mark the issue as fixed by replying with:
> >
> > #syz fix: fs/userfaultfd: Fix maple tree iterator in userfaultfd_unregister()
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection