lkml.org 
[lkml]   [2022]   [Jul]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [syzbot] KASAN: use-after-free Read in kill_fasync
From
Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in kill_fasync

IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
Bluetooth: hci0: command 0x0409 tx timeout
==================================================================
BUG: KASAN: use-after-free in kill_fasync+0x45e/0x470 fs/fcntl.c:1014
Read of size 8 at addr ffff88807d1e9168 by task kworker/1:3/3621

CPU: 1 PID: 3621 Comm: kworker/1:3 Not tainted 5.19.0-rc4-next-20220628-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Workqueue: events key_garbage_collector
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:317 [inline]
print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
kasan_report+0xbe/0x1f0 mm/kasan/report.c:495
kill_fasync+0x45e/0x470 fs/fcntl.c:1014
post_one_notification.isra.0+0x71a/0x9d0 kernel/watch_queue.c:131
remove_watch_from_object+0x35a/0x9d0 kernel/watch_queue.c:530
remove_watch_list include/linux/watch_queue.h:115 [inline]
key_gc_unused_keys.constprop.0+0x2e5/0x600 security/keys/gc.c:135
key_garbage_collector+0x3d7/0x920 security/keys/gc.c:297
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e9/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
</TASK>

Allocated by task 4105:
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_kmalloc mm/kasan/common.c:515 [inline]
____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
alloc_pipe_info+0x105/0x590 fs/pipe.c:790
get_pipe_inode fs/pipe.c:881 [inline]
create_pipe_files+0x8d/0x880 fs/pipe.c:913
__do_pipe_flags fs/pipe.c:962 [inline]
do_pipe2+0x96/0x1b0 fs/pipe.c:1010
__do_sys_pipe2 fs/pipe.c:1028 [inline]
__se_sys_pipe2 fs/pipe.c:1026 [inline]
__x64_sys_pipe2+0x50/0x70 fs/pipe.c:1026
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 4104:
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+0x166/0x1c0 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:200 [inline]
slab_free_hook mm/slub.c:1754 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780
slab_free mm/slub.c:3534 [inline]
kfree+0xe2/0x4d0 mm/slub.c:4562
put_pipe_info fs/pipe.c:711 [inline]
pipe_release+0x2b6/0x310 fs/pipe.c:734
__fput+0x277/0x9d0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:177
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
exit_to_user_mode_prepare+0x23c/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

The buggy address belongs to the object at ffff88807d1e9000
which belongs to the cache kmalloc-cg-512 of size 512
The buggy address is located 360 bytes inside of
512-byte region [ffff88807d1e9000, ffff88807d1e9200)

The buggy address belongs to the physical page:
page:ffffea0001f47a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7d1e8
head:ffffea0001f47a00 order:2 compound_mapcount:0 compound_pincount:0
memcg:ffff88807c9f0b01
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888011842dc0
raw: 0000000000000000 0000000080100010 00000001ffffffff ffff88807c9f0b01
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2958, tgid 2958 (klogd), ts 15679614274, free_ts 14007295278
prep_new_page mm/page_alloc.c:2535 [inline]
get_page_from_freelist+0x210d/0x3a30 mm/page_alloc.c:4282
__alloc_pages+0x1c7/0x510 mm/page_alloc.c:5506
alloc_pages+0x1aa/0x310 mm/mempolicy.c:2280
alloc_slab_page mm/slub.c:1824 [inline]
allocate_slab+0x27e/0x3d0 mm/slub.c:1969
new_slab mm/slub.c:2029 [inline]
___slab_alloc+0x89d/0xef0 mm/slub.c:3031
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
slab_alloc_node mm/slub.c:3209 [inline]
__kmalloc_node_track_caller+0x360/0x480 mm/slub.c:4955
kmalloc_reserve net/core/skbuff.c:358 [inline]
__alloc_skb+0xd9/0x340 net/core/skbuff.c:430
alloc_skb include/linux/skbuff.h:1249 [inline]
alloc_skb_with_frags+0x93/0x6d0 net/core/skbuff.c:5990
sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2663
unix_dgram_sendmsg+0x415/0x1b60 net/unix/af_unix.c:1884
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:734
__sys_sendto+0x21a/0x320 net/socket.c:2116
__do_sys_sendto net/socket.c:2128 [inline]
__se_sys_sendto net/socket.c:2124 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2124
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:1453 [inline]
free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1503
free_unref_page_prepare mm/page_alloc.c:3383 [inline]
free_unref_page+0x19/0x4d0 mm/page_alloc.c:3479
free_contig_range+0xb1/0x180 mm/page_alloc.c:9400
destroy_args+0xa8/0x64c mm/debug_vm_pgtable.c:1031
debug_vm_pgtable+0x2954/0x29e5 mm/debug_vm_pgtable.c:1354
do_one_initcall+0xfe/0x650 init/main.c:1300
do_initcall_level init/main.c:1375 [inline]
do_initcalls init/main.c:1391 [inline]
do_basic_setup init/main.c:1410 [inline]
kernel_init_freeable+0x6b1/0x73a init/main.c:1617
kernel_init+0x1a/0x1d0 init/main.c:1506
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302

Memory state around the buggy address:
ffff88807d1e9000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807d1e9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807d1e9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807d1e9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807d1e9200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit: cb71b93c Add linux-next specific files for 20220628
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=134d24c8080000
kernel config: https://syzkaller.appspot.com/x/.config?x=695e91d821f66ab5
dashboard link: https://syzkaller.appspot.com/bug?extid=382c8824777dca2812fe
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=105a9782080000

\
 
 \ /
  Last update: 2022-07-11 13:51    [W:0.075 / U:0.608 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site