KASAN: use-after-free Read in filp_close

Status: fixed on 2023/02/24 13:50
Subsystems: io-uring fs
[Documentation on labels]
Reported-by: syzbot+47dd250f527cb7bebf24@syzkaller.appspotmail.com
Fix commit: 40a1926022d1 fix the breakage in close_fd_get_file() calling conventions change
First crash: 1524d, last: 1290d
Cause bisection: introduced by (bisect log) :
commit 6319194ec57b0452dcda4589d24c4e7db299c5bf
Author: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu May 12 21:08:03 2022 +0000

  Unify the primitives for file descriptor closing

Crash: KASAN: use-after-free Read in filp_close (log)
Repro: C syz .config
  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] KASAN: use-after-free Read in filp_close 3 (7) 2022/06/05 18:29
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-54 KASAN: use-after-free Read in filp_close 19 C 3 1817d 2022d 0/2 auto-obsoleted due to no activity on 2023/04/21 02:05
upstream KASAN: null-ptr-deref Read in filp_close (2) fs 19 C 3 1840d 1948d 20/29 fixed on 2021/11/10 13:22
android-5-10 general protection fault in filp_close 2 1 1220d 1220d 0/2 auto-obsoleted due to no activity on 2023/06/22 23:34
android-5-15 general protection fault in filp_close 2 1 102d 102d 0/2 auto-obsoleted due to no activity on 2026/07/14 19:12
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2022/06/05 18:10 17m viro@zeniv.linux.org.uk git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git work.fd OK
2022/06/05 11:38 17m hdanton@sina.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 952923ddc011 OK

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_long_read include/linux/atomic/atomic-instrumented.h:1265 [inline]
BUG: KASAN: use-after-free in filp_close+0x22/0x160 fs/open.c:1382
Read of size 8 at addr ffff88801eb90070 by task syz-executor335/4998

CPU: 1 PID: 4998 Comm: syz-executor335 Not tainted 5.18.0-syzkaller-13842-g952923ddc011 #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
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_long_read include/linux/atomic/atomic-instrumented.h:1265 [inline]
 filp_close+0x22/0x160 fs/open.c:1382
 close_files fs/file.c:432 [inline]
 put_files_struct fs/file.c:447 [inline]
 put_files_struct+0x1d0/0x350 fs/file.c:444
 exit_files+0x7e/0xa0 fs/file.c:464
 do_exit+0xac8/0x2a00 kernel/exit.c:790
 do_group_exit+0xd2/0x2f0 kernel/exit.c:925
 get_signal+0x2542/0x2600 kernel/signal.c:2857
 arch_do_signal_or_restart+0x82/0x20f0 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop kernel/entry/common.c:166 [inline]
 exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f556b96d149
Code: Unable to access opcode bytes at RIP 0x7f556b96d11f.
RSP: 002b:00007f556b91a2f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f556b9f0428 RCX: 00007f556b96d149
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f556b9f042c
RBP: 00007f556b9f0420 R08: 0200000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f556b9f042c
R13: 00007f556b9be064 R14: 0200000000000000 R15: 0000000000000005
 </TASK>

Allocated by task 4998:
 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]
 slab_alloc_node mm/slub.c:3214 [inline]
 slab_alloc mm/slub.c:3222 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3229 [inline]
 kmem_cache_alloc+0x204/0x3b0 mm/slub.c:3239
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 __alloc_file+0x21/0x270 fs/file_table.c:138
 alloc_empty_file+0x6d/0x170 fs/file_table.c:187
 path_openat+0xe4/0x2910 fs/namei.c:3639
 do_filp_open+0x1aa/0x400 fs/namei.c:3680
 do_sys_openat2+0x16d/0x4c0 fs/open.c:1278
 do_sys_open fs/open.c:1294 [inline]
 __do_sys_openat fs/open.c:1310 [inline]
 __se_sys_openat fs/open.c:1305 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1305
 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+0x46/0xb0

Freed by task 22:
 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+0xdd/0x5a0 mm/slub.c:3524
 rcu_do_batch kernel/rcu/tree.c:2578 [inline]
 rcu_core+0x7b1/0x1880 kernel/rcu/tree.c:2838
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:571

Last potentially related work creation:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
 call_rcu+0x99/0x790 kernel/rcu/tree.c:3126
 task_work_run+0xdd/0x1a0 kernel/task_work.c:177
 ptrace_notify+0x114/0x140 kernel/signal.c:2353
 ptrace_report_syscall include/linux/ptrace.h:420 [inline]
 ptrace_report_syscall_exit include/linux/ptrace.h:482 [inline]
 syscall_exit_work kernel/entry/common.c:249 [inline]
 syscall_exit_to_user_mode_prepare+0xdb/0x230 kernel/entry/common.c:276
 __syscall_exit_to_user_mode_work kernel/entry/common.c:281 [inline]
 syscall_exit_to_user_mode+0x9/0x50 kernel/entry/common.c:294
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Second to last potentially related work creation:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
 task_work_add+0x3a/0x1f0 kernel/task_work.c:48
 fput fs/file_table.c:378 [inline]
 fput+0xe7/0x190 fs/file_table.c:371
 io_close fs/io_uring.c:6053 [inline]
 io_issue_sqe+0x3f29/0x9780 fs/io_uring.c:8464
 io_queue_sqe fs/io_uring.c:8794 [inline]
 io_submit_sqe fs/io_uring.c:9058 [inline]
 io_submit_sqes+0x161d/0x8000 fs/io_uring.c:9169
 __do_sys_io_uring_enter+0x1112/0x2300 fs/io_uring.c:12101
 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+0x46/0xb0

The buggy address belongs to the object at ffff88801eb90000
 which belongs to the cache filp of size 456
The buggy address is located 112 bytes inside of
 456-byte region [ffff88801eb90000, ffff88801eb901c8)

The buggy address belongs to the physical page:
page:ffffea00007ae400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1eb90
head:ffffea00007ae400 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea00007aa900 dead000000000007 ffff8881400078c0
raw: 0000000000000000 00000000000c000c 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 3442, tgid 3442 (rm), ts 37980828809, free_ts 17882496614
 prep_new_page mm/page_alloc.c:2456 [inline]
 get_page_from_freelist+0x1290/0x3b70 mm/page_alloc.c:4198
 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5426
 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272
 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
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3089
 slab_alloc_node mm/slub.c:3180 [inline]
 slab_alloc mm/slub.c:3222 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3229 [inline]
 kmem_cache_alloc+0x360/0x3b0 mm/slub.c:3239
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 __alloc_file+0x21/0x270 fs/file_table.c:138
 alloc_empty_file+0x6d/0x170 fs/file_table.c:187
 path_openat+0xe4/0x2910 fs/namei.c:3639
 do_filp_open+0x1aa/0x400 fs/namei.c:3680
 do_sys_openat2+0x16d/0x4c0 fs/open.c:1278
 do_sys_open fs/open.c:1294 [inline]
 __do_sys_openat fs/open.c:1310 [inline]
 __se_sys_openat fs/open.c:1305 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1305
 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+0x46/0xb0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1371 [inline]
 free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1421
 free_unref_page_prepare mm/page_alloc.c:3343 [inline]
 free_unref_page+0x19/0x6a0 mm/page_alloc.c:3438
 __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]
 __kmem_cache_alloc_lru mm/slub.c:3229 [inline]
 kmem_cache_alloc+0x204/0x3b0 mm/slub.c:3239
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 __alloc_file+0x21/0x270 fs/file_table.c:138
 alloc_empty_file+0x6d/0x170 fs/file_table.c:187
 path_openat+0xe4/0x2910 fs/namei.c:3639
 do_filp_open+0x1aa/0x400 fs/namei.c:3680
 do_sys_openat2+0x16d/0x4c0 fs/open.c:1278
 do_sys_open fs/open.c:1294 [inline]
 __do_sys_openat fs/open.c:1310 [inline]
 __se_sys_openat fs/open.c:1305 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1305
 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+0x46/0xb0

Memory state around the buggy address:
 ffff88801eb8ff00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
 ffff88801eb8ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801eb90000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff88801eb90080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801eb90100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/06/05 22:31 upstream 952923ddc011 c8857892 .config strace log report syz C ci-upstream-kasan-gce KASAN: use-after-free Read in filp_close
2022/06/05 08:49 upstream 952923ddc011 c8857892 .config console log report syz C ci-upstream-kasan-gce-root KASAN: use-after-free Read in filp_close
2022/06/05 12:39 upstream 952923ddc011 c8857892 .config console log report syz ci-upstream-kasan-gce-smack-root KASAN: use-after-free Read in filp_close
2022/06/05 20:20 upstream 952923ddc011 c8857892 .config console log report info ci-upstream-kasan-gce-selinux-root KASAN: use-after-free Read in filp_close
2022/06/05 16:54 upstream 952923ddc011 c8857892 .config console log report info ci-upstream-kasan-gce-selinux-root KASAN: use-after-free Read in filp_close
2022/06/05 07:29 upstream 952923ddc011 c8857892 .config console log report info ci-upstream-kasan-gce-smack-root KASAN: use-after-free Read in filp_close
2022/06/05 05:08 upstream 952923ddc011 c8857892 .config console log report info ci-upstream-kasan-gce-root KASAN: use-after-free Read in filp_close
2023/01/14 01:48 linux-next 0a093b2893c7 529798b0 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2023/01/13 11:12 linux-next 0a093b2893c7 96166539 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2023/01/12 12:35 linux-next 0a093b2893c7 96166539 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2023/01/12 07:03 linux-next 0a093b2893c7 96166539 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2023/01/12 06:51 linux-next 0a093b2893c7 96166539 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2022/06/05 01:52 linux-next 1cfd968b58a1 c8857892 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2022/06/04 23:51 linux-next 1cfd968b58a1 c8857892 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2022/06/04 23:27 linux-next 1cfd968b58a1 c8857892 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2022/05/25 00:04 linux-next 09ce5091ff97 647c0e27 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
2022/05/24 10:48 linux-next 09ce5091ff97 e7f9308d .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in filp_close
* Struck through repros no longer work on HEAD.