KASAN: use-after-free Read in nr_release

From: syzbot
Date: Sat Jun 08 2019 - 04:40:27 EST

Next message: Jens Axboe: "Re: [PATCH] block: fix a crash in do_task_dead()"
Previous message: Hariprasad Kelam: "[PATCH] ipv6: exthdrs: fix warning comparison to bool"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hello,

syzbot found the following crash on:

HEAD commit: 85cb9287 net: rds: fix memory leak in rds_ib_flush_mr_pool
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=133e162ea00000
kernel config: https://syzkaller.appspot.com/x/.config?x=4f721a391cd46ea
dashboard link: https://syzkaller.appspot.com/bug?extid=6eaef7158b19e3fec3a0
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6eaef7158b19e3fec3a0@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123
Read of size 4 at addr ffff88807bd1a3c0 by task syz-executor.4/31693

CPU: 1 PID: 31693 Comm: syz-executor.4 Not tainted 5.2.0-rc2+ #43
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
__kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
kasan_report+0x12/0x20 mm/kasan/common.c:614
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x123/0x190 mm/kasan/generic.c:191
kasan_check_read+0x11/0x20 mm/kasan/common.c:94
atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123
refcount_inc_checked+0x17/0x70 lib/refcount.c:156
sock_hold include/net/sock.h:654 [inline]
nr_release+0x62/0x3b0 net/netrom/af_netrom.c:523
__sock_release+0xce/0x2a0 net/socket.c:607
sock_close+0x1b/0x30 net/socket.c:1279
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:168
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
do_syscall_64+0x58e/0x680 arch/x86/entry/common.c:304
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x412f61
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffda8e7f4d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000412f61
RDX: 0000000000000000 RSI: ffffffff87168e98 RDI: 0000000000000004
RBP: 0000000000000001 R08: ffffffff81009897 R09: 0000000017981f41
R10: 00007ffda8e7f5b0 R11: 0000000000000293 R12: 000000000075c920
R13: 000000000075c920 R14: 000000000018a8f4 R15: 000000000075c10c

Allocated by task 31694:
save_stack+0x23/0x90 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_kmalloc mm/kasan/common.c:489 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503
__do_kmalloc mm/slab.c:3660 [inline]
__kmalloc+0x15c/0x740 mm/slab.c:3669
kmalloc include/linux/slab.h:552 [inline]
sk_prot_alloc+0x19c/0x2e0 net/core/sock.c:1608
sk_alloc+0x39/0xf70 net/core/sock.c:1662
nr_create+0xb9/0x5e0 net/netrom/af_netrom.c:436
__sock_create+0x3d8/0x730 net/socket.c:1430
sock_create net/socket.c:1481 [inline]
__sys_socket+0x103/0x220 net/socket.c:1523
__do_sys_socket net/socket.c:1532 [inline]
__se_sys_socket net/socket.c:1530 [inline]
__x64_sys_socket+0x73/0xb0 net/socket.c:1530
do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 31693:
save_stack+0x23/0x90 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
__cache_free mm/slab.c:3432 [inline]
kfree+0xcf/0x220 mm/slab.c:3755
sk_prot_free net/core/sock.c:1645 [inline]
__sk_destruct+0x4f7/0x6e0 net/core/sock.c:1731
sk_destruct+0x7b/0x90 net/core/sock.c:1739
__sk_free+0xce/0x300 net/core/sock.c:1750
sk_free+0x42/0x50 net/core/sock.c:1761
sock_put include/net/sock.h:1728 [inline]
nr_release+0x332/0x3b0 net/netrom/af_netrom.c:557
__sock_release+0xce/0x2a0 net/socket.c:607
sock_close+0x1b/0x30 net/socket.c:1279
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:168
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
do_syscall_64+0x58e/0x680 arch/x86/entry/common.c:304
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88807bd1a340
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
2048-byte region [ffff88807bd1a340, ffff88807bd1ab40)
The buggy address belongs to the page:
page:ffffea0001ef4680 refcount:1 mapcount:0 mapping:ffff8880aa400c40 index:0xffff88807bd1b440 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea0002a48788 ffffea00018fc508 ffff8880aa400c40
raw: ffff88807bd1b440 ffff88807bd1a340 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88807bd1a280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807bd1a300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb

ffff88807bd1a380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^
ffff88807bd1a400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807bd1a480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
This bug 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 syzkaller@xxxxxxxxxxxxxxxxx

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

Next message: Jens Axboe: "Re: [PATCH] block: fix a crash in do_task_dead()"
Previous message: Hariprasad Kelam: "[PATCH] ipv6: exthdrs: fix warning comparison to bool"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]