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Date: Fri, 02 Feb 2018 09:47:01 -0800
From: syzbot <syzbot+347bd5acde002e353a36@...kaller.appspotmail.com>
To: davem@...emloft.net, kuznet@....inr.ac.ru,
linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
syzkaller-bugs@...glegroups.com, yoshfuji@...ux-ipv6.org
Subject: KASAN: use-after-free Read in inet_shutdown
syzbot has found reproducer for the following crash on upstream commit
4bf772b14675411a69b3c807f73006de0fe4b649 (Fri Feb 2 01:48:47 2018 +0000)
Merge tag 'drm-for-v4.16' of git://people.freedesktop.org/~airlied/linux
So far this crash happened 14 times on mmots, net-next, upstream.
C reproducer is attached.
syzkaller reproducer is attached.
Raw console output is attached.
compiler: gcc (GCC) 7.1.1 20170620
.config is attached.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+347bd5acde002e353a36@...kaller.appspotmail.com
It will help syzbot understand when the bug is fixed.
==================================================================
BUG: KASAN: use-after-free in inet_shutdown+0x2d4/0x350
net/ipv4/af_inet.c:819
Read of size 4 at addr ffff8801c008f540 by task syzkaller114342/5197
CPU: 0 PID: 5197 Comm: syzkaller114342 Not tainted 4.15.0+ #292
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
print_address_description+0x73/0x250 mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report+0x25b/0x340 mm/kasan/report.c:409
__asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
inet_shutdown+0x2d4/0x350 net/ipv4/af_inet.c:819
pppol2tp_session_close+0x92/0xf0 net/l2tp/l2tp_ppp.c:430
l2tp_tunnel_closeall+0x305/0x410 net/l2tp/l2tp_core.c:1285
l2tp_udp_encap_destroy+0x95/0x100 net/l2tp/l2tp_core.c:1308
udpv6_destroy_sock+0x161/0x190 net/ipv6/udp.c:1407
sk_common_release+0x6b/0x2f0 net/core/sock.c:2999
udp_lib_close+0x15/0x20 include/net/udp.h:203
inet_release+0xed/0x1c0 net/ipv4/af_inet.c:427
inet6_release+0x50/0x70 net/ipv6/af_inet6.c:435
sock_release+0x8d/0x1e0 net/socket.c:595
sock_close+0x16/0x20 net/socket.c:1149
__fput+0x327/0x7e0 fs/file_table.c:209
____fput+0x15/0x20 fs/file_table.c:243
task_work_run+0x199/0x270 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:165
prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
entry_SYSCALL_64_fastpath+0x9e/0xa0
RIP: 0033:0x44bbd9
RSP: 002b:00007f8e19861ce8 EFLAGS: 00000206 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00000000006ddc24 RCX: 000000000044bbd9
RDX: 000000000044bbd9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000006ddc20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ffc84c0bb3f R14: 00007f8e198629c0 R15: 000000000000000d
Allocated by task 5216:
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
kmem_cache_alloc+0x12e/0x760 mm/slab.c:3540
sock_alloc_inode+0x70/0x300 net/socket.c:244
alloc_inode+0x65/0x180 fs/inode.c:209
new_inode_pseudo+0x69/0x190 fs/inode.c:891
sock_alloc+0x41/0x270 net/socket.c:565
__sock_create+0x148/0x850 net/socket.c:1249
sock_create net/socket.c:1325 [inline]
SYSC_socket net/socket.c:1355 [inline]
SyS_socket+0xeb/0x1d0 net/socket.c:1335
entry_SYSCALL_64_fastpath+0x29/0xa0
Freed by task 5291:
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
__cache_free mm/slab.c:3484 [inline]
kmem_cache_free+0x83/0x2a0 mm/slab.c:3742
sock_destroy_inode+0x56/0x70 net/socket.c:274
destroy_inode+0x15d/0x200 fs/inode.c:266
evict+0x57e/0x920 fs/inode.c:571
iput_final fs/inode.c:1516 [inline]
iput+0x7b9/0xaf0 fs/inode.c:1543
dentry_unlink_inode+0x4b0/0x5e0 fs/dcache.c:371
__dentry_kill+0x3de/0x700 fs/dcache.c:575
dentry_kill fs/dcache.c:616 [inline]
dput.part.21+0x6fb/0x830 fs/dcache.c:826
dput+0x1f/0x30 fs/dcache.c:790
__fput+0x51c/0x7e0 fs/file_table.c:227
____fput+0x15/0x20 fs/file_table.c:243
task_work_run+0x199/0x270 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:165
prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
entry_SYSCALL_64_fastpath+0x9e/0xa0
The buggy address belongs to the object at ffff8801c008f540
which belongs to the cache sock_inode_cache of size 992
The buggy address is located 0 bytes inside of
992-byte region [ffff8801c008f540, ffff8801c008f920)
The buggy address belongs to the page:
page:ffffea00070023c0 count:1 mapcount:0 mapping:ffff8801c008f0c0
index:0xffff8801c008fffd
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c008f0c0 ffff8801c008fffd 0000000100000003
raw: ffffea00070023a0 ffffea00070024a0 ffff8801d9fe6380 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801c008f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8801c008f480: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8801c008f500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
^
ffff8801c008f580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801c008f600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
View attachment "raw.log.txt" of type "text/plain" (70429 bytes)
View attachment "repro.syz.txt" of type "text/plain" (1483 bytes)
View attachment "repro.c.txt" of type "text/plain" (16078 bytes)
View attachment "config.txt" of type "text/plain" (136833 bytes)
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