Subject: KASAN: stack-out-of-bounds Read in xfrm_state_find (2)

From: syzbot <[email-masked]>
Date: Wed, 01 Nov 2017 10:45:01 -0700

Hello,

syzkaller hit the following crash on  
36ef71cae353f88fd6e095e2aaa3e5953af1685d
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
C reproducer is attached
syzkaller reproducer is attached. See https://goo.gl/kgGztJ
for information about syzkaller reproducers

BUG: KASAN: stack-out-of-bounds in xfrm_state_find+0x303d/0x3170  
net/xfrm/xfrm_state.c:1051
Read of size 4 at addr ffff88003adb7760 by task syzkaller429801/2969

CPU: 3 PID: 2969 Comm: syzkaller429801 Not tainted  
4.14.0-rc5-next-20171018+ #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:16 [inline]
  dump_stack+0x194/0x257 lib/dump_stack.c:52
  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+0x303d/0x3170 net/xfrm/xfrm_state.c:1051
  xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:1388 [inline]
  xfrm_tmpl_resolve+0x309/0xc00 net/xfrm/xfrm_policy.c:1432
  xfrm_resolve_and_create_bundle+0x186/0x24a0 net/xfrm/xfrm_policy.c:1830
  xfrm_lookup+0xf0a/0x2540 net/xfrm/xfrm_policy.c:2141
  xfrm_lookup_route+0x39/0x1a0 net/xfrm/xfrm_policy.c:2259
  ip_route_output_flow+0x7c/0xa0 net/ipv4/route.c:2555
  udp_sendmsg+0x19b8/0x2cd0 net/ipv4/udp.c:1022
  udpv6_sendmsg+0x743/0x3380 net/ipv6/udp.c:1186
  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+0x352/0x5a0 net/socket.c:1749
  SyS_sendto+0x40/0x50 net/socket.c:1717
  entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4350a9
RSP: 002b:00007ffe01d21408 EFLAGS: 00000217 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 00000000004350a9
RDX: 0000000000000000 RSI: 0000000020efcf90 RDI: 0000000000000003
RBP: 0000000000000082 R08: 0000000020efc000 R09: 0000000000000010
R10: 0000000000004090 R11: 0000000000000217 R12: 0000000000000000
R13: 0000000000401a20 R14: 0000000000401ab0 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0000eb6dc0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x100000000000000()
raw: 0100000000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff88003adb7600: 00 f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 f2 f2
  ffff88003adb7680: f2 f2 f2 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2 00 00 00
> ffff88003adb7700: 00 f2 f2 f2 f2 00 00 00 00 00 00 00 f2 f2 f2 f2
                                                        ^
  ffff88003adb7780: f2 00 00 00 00 00 00 00 00 00 f2 f2 f2 f3 f3 f3
  ffff88003adb7800: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

---
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