Subject: KASAN: stack-out-of-bounds Read in xfrm_state_find (3)

From: syzbot <[email-masked]>
Date: Mon, 20 Nov 2017 09:22:00 -0800

Hello,

syzkaller hit the following crash on  
1deab8ce2c91e3b16563b7a7ea150f82334262ec
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.

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

==================================================================
BUG: KASAN: stack-out-of-bounds in xfrm_state_find+0x30fc/0x3230  
net/xfrm/xfrm_state.c:1051
Read of size 4 at addr ffff8801c06b7af8 by task syz-executor4/24212

CPU: 0 PID: 24212 Comm: syz-executor4 Not tainted 4.14.0+ #126
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
IPv6: ADDRCONF(NETDEV_UP): sit0: link is not ready
  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
  xfrm_state_find+0x30fc/0x3230 net/xfrm/xfrm_state.c:1051
  xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:1388 [inline]
  xfrm_tmpl_resolve+0x2fb/0xbd0 net/xfrm/xfrm_policy.c:1432
  xfrm_resolve_and_create_bundle+0x11b/0x2600 net/xfrm/xfrm_policy.c:1821
  xfrm_lookup+0x1574/0x23f0 net/xfrm/xfrm_policy.c:2146
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7  
sclass=netlink_route_socket pig=24256 comm=syz-executor6
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0  
sclass=netlink_route_socket pig=24256 comm=syz-executor6
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7  
sclass=netlink_route_socket pig=24257 comm=syz-executor6
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0  
sclass=netlink_route_socket pig=24256 comm=syz-executor6
  xfrm_lookup_route+0x39/0x1a0 net/xfrm/xfrm_policy.c:2264
  ip_route_output_flow+0x7c/0xa0 net/ipv4/route.c:2559
  raw_sendmsg+0xc4f/0x3920 net/ipv4/raw.c:633
  inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
  sock_sendmsg_nosec net/socket.c:632 [inline]
  sock_sendmsg+0xca/0x110 net/socket.c:642
  SYSC_sendto+0x358/0x5a0 net/socket.c:1749
  SyS_sendto+0x40/0x50 net/socket.c:1717
  entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452879
RSP: 002b:00007f4737804be8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452879
RDX: 0000000000000000 RSI: 0000000020098000 RDI: 0000000000000015
RBP: 0000000000000086 R08: 0000000020c24000 R09: 0000000000000010
R10: fffffffffffffffe R11: 0000000000000212 R12: 00000000006ed3b8
R13: 00000000ffffffff R14: 00007f47378056d4 R15: 000000000000000c

The buggy address belongs to the page:
page:ffffea000701adc0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8801c06b7980: f2 f2 f2 f2 00 f2 f2 f2 f2 f2 f2 f2 00 00 00 f2
  ffff8801c06b7a00: f2 f2 f2 f2 00 00 00 00 f2 f2 f2 f2 00 00 00 00
> ffff8801c06b7a80: 00 00 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 f2
                                                                 ^
  ffff8801c06b7b00: f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 f2 f2 f2
  ffff8801c06b7b80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 f1 f1
==================================================================

---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to [email-masked].
Please credit me with: Reported-by: syzbot <[email-masked]>

syzbot will keep track of this bug report.
Once a fix for this bug is committed, please reply to this email with:
#syz fix: exact-commit-title
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug  
report.
Note: all commands must start from beginning of the line in the email body.