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KASAN: stack-out-of-bounds Write in ipip6_tunnel_locate

Status: fixed on 2018/05/08 18:30
Subsystems: net
[Documentation on labels]
Fix commit: b95211e066fc ipv6: sit: better validate user provided tunnel names
First crash: 2213d, last: 2205d

Sample crash report:
==================================================================
BUG: KASAN: stack-out-of-bounds in strlcpy include/linux/string.h:300 [inline]
BUG: KASAN: stack-out-of-bounds in ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254
Write of size 33 at addr ffff8801b64076d8 by task syzkaller932654/4453

CPU: 0 PID: 4453 Comm: syzkaller932654 Not tainted 4.16.0+ #1
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+0x1b9/0x29f lib/dump_stack.c:53
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 memcpy+0x37/0x50 mm/kasan/kasan.c:303
 strlcpy include/linux/string.h:300 [inline]
 ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254
 ipip6_tunnel_ioctl+0xe71/0x241b net/ipv6/sit.c:1221
 dev_ifsioc+0x43e/0xb90 net/core/dev_ioctl.c:334
 dev_ioctl+0x69a/0xcc0 net/core/dev_ioctl.c:525
 sock_ioctl+0x47e/0x680 net/socket.c:1015
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 SYSC_ioctl fs/ioctl.c:708 [inline]
 SyS_ioctl+0x24/0x30 fs/ioctl.c:706
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x43fe09
RSP: 002b:00007fff1291df58 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fe09
RDX: 00000000200001c0 RSI: 00000000000089f1 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 000000000000001c R09: 00000000004002c8
R10: 000000000000001c R11: 0000000000000213 R12: 0000000000401730
R13: 00000000004017c0 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0006d901c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 ffffea0006d90101 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b6407580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801b6407600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
>ffff8801b6407680: f1 f1 f1 f8 f2 f2 f2 f2 f2 f2 f2 00 00 f2 f2 00
                                                          ^
 ffff8801b6407700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801b6407780: 00 00 f1 f1 f1 f1 f8 f2 f2 f2 f2 f2 f2 f2 00 f2
==================================================================

Crashes (33):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/04/05 11:53 upstream 06dd3dfeea60 5e1ccffc .config console log report syz C ci-upstream-kasan-gce-root
2018/04/05 12:06 net-next-old 17dec0a94915 5e1ccffc .config console log report syz C ci-upstream-net-kasan-gce
2018/04/10 01:15 upstream fd40ffc72e2f b9f65507 .config console log report ci-upstream-kasan-gce
2018/04/09 11:01 upstream 3fd14cdcc05a f13fb445 .config console log report ci-upstream-kasan-gce
2018/04/09 11:01 upstream 3fd14cdcc05a f13fb445 .config console log report ci-upstream-kasan-gce-root
2018/04/08 22:36 upstream 3fd14cdcc05a 77bd5117 .config console log report ci-upstream-kasan-gce
2018/04/08 22:36 upstream 3fd14cdcc05a 77bd5117 .config console log report ci-upstream-kasan-gce-root
2018/04/07 18:54 upstream 3fd14cdcc05a 66f22a7f .config console log report ci-upstream-kasan-gce
2018/04/07 18:53 upstream 3fd14cdcc05a 66f22a7f .config console log report ci-upstream-kasan-gce-root
2018/04/07 15:28 upstream 3fd14cdcc05a 66f22a7f .config console log report ci-upstream-kasan-gce
2018/04/07 15:28 upstream 3fd14cdcc05a 66f22a7f .config console log report ci-upstream-kasan-gce-root
2018/04/06 12:41 upstream 38c23685b273 4f1152d4 .config console log report ci-upstream-kasan-gce-root
2018/04/06 12:40 upstream 38c23685b273 4f1152d4 .config console log report ci-upstream-kasan-gce
2018/04/05 22:57 upstream 3c8ba0d61d04 a932eae6 .config console log report ci-upstream-kasan-gce-root
2018/04/05 22:57 upstream 3c8ba0d61d04 a932eae6 .config console log report ci-upstream-kasan-gce-root
2018/04/05 22:50 upstream e02d37bf55a9 a932eae6 .config console log report ci-upstream-kasan-gce
2018/04/05 22:50 upstream e02d37bf55a9 a932eae6 .config console log report ci-upstream-kasan-gce
2018/04/05 19:49 upstream e02d37bf55a9 5e1ccffc .config console log report ci-upstream-kasan-gce
2018/04/05 19:44 upstream e02d37bf55a9 5e1ccffc .config console log report ci-upstream-kasan-gce
2018/04/05 19:34 upstream e02d37bf55a9 5e1ccffc .config console log report ci-upstream-kasan-gce
2018/04/05 19:31 upstream e02d37bf55a9 5e1ccffc .config console log report ci-upstream-kasan-gce
2018/04/05 11:23 upstream 06dd3dfeea60 5e1ccffc .config console log report ci-upstream-kasan-gce-root
2018/04/05 11:19 upstream 06dd3dfeea60 5e1ccffc .config console log report ci-upstream-kasan-gce-root
2018/04/05 11:07 upstream 06dd3dfeea60 5e1ccffc .config console log report ci-upstream-kasan-gce-root
2018/04/13 03:13 net-next-old 17dec0a94915 eb2295de .config console log report ci-upstream-net-kasan-gce
2018/04/11 20:22 net-next-old 17dec0a94915 9cd56d71 .config console log report ci-upstream-net-kasan-gce
2018/04/11 01:26 net-next-old 17dec0a94915 8b8de427 .config console log report ci-upstream-net-kasan-gce
2018/04/10 13:44 net-next-old 17dec0a94915 8e873e9d .config console log report ci-upstream-net-kasan-gce
2018/04/09 11:01 net-next-old 17dec0a94915 f13fb445 .config console log report ci-upstream-net-kasan-gce
2018/04/08 09:09 net-next-old 17dec0a94915 66f22a7f .config console log report ci-upstream-net-kasan-gce
2018/04/07 20:43 net-next-old 17dec0a94915 66f22a7f .config console log report ci-upstream-net-kasan-gce
2018/04/07 15:28 net-next-old 17dec0a94915 66f22a7f .config console log report ci-upstream-net-kasan-gce
2018/04/05 22:50 net-next-old 17dec0a94915 a932eae6 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.