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KASAN: use-after-free Read in erspan_build_header

Status: fixed on 2018/02/01 04:00
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+eefa384efad8d7997f20@syzkaller.appspotmail.com
Fix commit: b423d13c08a6 net: erspan: fix use-after-free
First crash: 2286d, last: 2277d
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH 4.14 000/193] 4.14.123-stable review 199 (199) 2019/05/31 05:16
[PATCH net] net: erspan: fix use-after-free 2 (2) 2018/01/24 21:53
KASAN: use-after-free Read in erspan_build_header 1 (2) 2018/01/22 22:42
▶ ▼ Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 KASAN: use-after-free Read in erspan_build_header C done 18 1808d 1842d 1/1 fixed on 2019/11/30 21:02

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698
Read of size 2 at addr ffff8801d85ca28b by task syzkaller325844/3653

CPU: 1 PID: 3653 Comm: syzkaller325844 Not tainted 4.15.0-rc9+ #274
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_load_n_noabort+0xf/0x20 mm/kasan/report.c:440
 erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698
 erspan_xmit+0x3b8/0x13b0 net/ipv4/ip_gre.c:740
 __netdev_start_xmit include/linux/netdevice.h:4042 [inline]
 netdev_start_xmit include/linux/netdevice.h:4051 [inline]
 packet_direct_xmit+0x315/0x6b0 net/packet/af_packet.c:266
 packet_snd net/packet/af_packet.c:2943 [inline]
 packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2968
 sock_sendmsg_nosec net/socket.c:638 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:648
 SYSC_sendto+0x361/0x5c0 net/socket.c:1729
 SyS_sendto+0x40/0x50 net/socket.c:1697
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x445579
RSP: 002b:00007ffefb59c4b8 EFLAGS: 00000217 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000445579
RDX: 0000000000000000 RSI: 0000000020003fd9 RDI: 0000000000000004
RBP: 00000000004a7113 R08: 0000000020008000 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000217 R12: 00007ffefb59c568
R13: 0000000000402740 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0007617280 count:0 mapcount:0 mapping:          (null) index:0xffff8801d85cad40
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 ffff8801d85cad40 00000000ffffffff
raw: dead000000000100 dead000000000200 ffff8801dae2c600 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d85ca180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801d85ca200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8801d85ca280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff8801d85ca300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801d85ca380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (60):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/01/22 18:23 upstream 0d665e7b109d 228e3d95 .config console log report syz C ci-upstream-kasan-gce
2018/01/22 17:45 upstream 0d665e7b109d 228e3d95 .config console log report syz C ci-upstream-kasan-gce
2018/01/22 17:21 upstream 0d665e7b109d 228e3d95 .config console log report syz C ci-upstream-kasan-gce
2018/01/22 14:31 upstream 0d665e7b109d 228e3d95 .config console log report syz C ci-upstream-kasan-gce
2018/01/22 18:23 upstream 0d665e7b109d 228e3d95 .config console log report syz C ci-upstream-kasan-gce-386
2018/01/22 17:42 upstream 0d665e7b109d 228e3d95 .config console log report syz C ci-upstream-kasan-gce-386
2018/01/22 15:51 upstream 0d665e7b109d 228e3d95 .config console log report syz C ci-upstream-kasan-gce-386
2018/01/22 14:50 upstream 0d665e7b109d 228e3d95 .config console log report syz C ci-upstream-kasan-gce-386
2018/02/01 00:02 upstream 3da90b159b14 02553e22 .config console log report ci-upstream-kasan-gce
2018/01/31 20:26 upstream 3da90b159b14 02553e22 .config console log report ci-upstream-kasan-gce
2018/01/31 15:04 upstream 3da90b159b14 02553e22 .config console log report ci-upstream-kasan-gce
2018/01/31 11:48 upstream 72906f38934a 02553e22 .config console log report ci-upstream-kasan-gce
2018/01/31 10:57 upstream 72906f38934a 02553e22 .config console log report ci-upstream-kasan-gce
2018/01/31 08:58 upstream 72906f38934a 02553e22 .config console log report ci-upstream-kasan-gce
2018/01/31 08:55 upstream 72906f38934a 02553e22 .config console log report ci-upstream-kasan-gce
2018/01/31 07:11 upstream 72906f38934a 02553e22 .config console log report ci-upstream-kasan-gce
2018/01/30 22:31 upstream 72906f38934a a899be78 .config console log report ci-upstream-kasan-gce
2018/01/30 16:42 upstream 6304672b7f0a a899be78 .config console log report ci-upstream-kasan-gce
2018/01/30 13:45 upstream 6304672b7f0a a899be78 .config console log report ci-upstream-kasan-gce
2018/01/30 13:20 upstream 6304672b7f0a a899be78 .config console log report ci-upstream-kasan-gce
2018/01/30 11:55 upstream 6304672b7f0a 08d47756 .config console log report ci-upstream-kasan-gce
2018/01/30 09:02 upstream 6304672b7f0a 08d47756 .config console log report ci-upstream-kasan-gce
2018/01/30 08:12 upstream 6304672b7f0a 08d47756 .config console log report ci-upstream-kasan-gce
2018/01/29 12:17 upstream d8a5b80568a9 08d47756 .config console log report ci-upstream-kasan-gce
2018/01/29 00:04 upstream 24b1cccf9229 08d47756 .config console log report ci-upstream-kasan-gce
2018/01/28 21:33 upstream 24b1cccf9229 08d47756 .config console log report ci-upstream-kasan-gce
2018/01/27 11:02 upstream c4e0ca7fa241 1d18b112 .config console log report ci-upstream-kasan-gce
2018/01/27 06:55 upstream c4e0ca7fa241 1d18b112 .config console log report ci-upstream-kasan-gce
2018/01/27 05:20 upstream c4e0ca7fa241 1d18b112 .config console log report ci-upstream-kasan-gce
2018/01/26 23:06 upstream 993ca2068b04 1d18b112 .config console log report ci-upstream-kasan-gce
2018/01/26 12:37 upstream 993ca2068b04 1d18b112 .config console log report ci-upstream-kasan-gce
2018/01/25 23:07 upstream 6e20630e3004 1d18b112 .config console log report ci-upstream-kasan-gce
2018/01/25 18:06 upstream 5b7d27967dab 6b2a715e .config console log report ci-upstream-kasan-gce
2018/01/25 08:30 upstream 5b7d27967dab 6b2a715e .config console log report ci-upstream-kasan-gce
2018/01/25 03:48 upstream 5132ede0fe80 866f1102 .config console log report ci-upstream-kasan-gce
2018/01/24 10:12 upstream 1f07476ec143 a5b7566c .config console log report ci-upstream-kasan-gce
2018/01/23 14:05 upstream 1995266727fa a5b7566c .config console log report ci-upstream-kasan-gce
2018/01/23 06:48 upstream a0ec1ded22e6 228e3d95 .config console log report ci-upstream-kasan-gce
2018/01/23 05:48 upstream a0ec1ded22e6 228e3d95 .config console log report ci-upstream-kasan-gce
2018/01/23 04:29 upstream a0ec1ded22e6 228e3d95 .config console log report ci-upstream-kasan-gce
2018/01/22 17:13 upstream 0d665e7b109d 228e3d95 .config console log report ci-upstream-kasan-gce
2018/01/22 17:13 upstream 0d665e7b109d 228e3d95 .config console log report ci-upstream-kasan-gce
2018/01/22 13:56 upstream 0d665e7b109d 228e3d95 .config console log report ci-upstream-kasan-gce
2018/02/01 01:37 upstream 3da90b159b14 02553e22 .config console log report ci-upstream-kasan-gce-386
2018/02/01 01:00 upstream 3da90b159b14 02553e22 .config console log report ci-upstream-kasan-gce-386
2018/01/31 19:00 upstream 3da90b159b14 02553e22 .config console log report ci-upstream-kasan-gce-386
2018/01/31 18:29 upstream 3da90b159b14 02553e22 .config console log report ci-upstream-kasan-gce-386
2018/01/31 17:33 upstream 3da90b159b14 02553e22 .config console log report ci-upstream-kasan-gce-386
* Struck through repros no longer work on HEAD.