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KASAN: stack-out-of-bounds Read in strnstr

Status: closed as invalid on 2018/09/24 12:33
Subsystems: apparmor
[Documentation on labels]
First crash: 2012d, last: 2012d

Sample crash report:
==================================================================
BUG: KASAN: stack-out-of-bounds in memcmp+0xe3/0x160 lib/string.c:861
Read of size 1 at addr ffff8801bad8f400 by task syz-executor192/5386

CPU: 1 PID: 5386 Comm: syz-executor192 Not tainted 4.19.0-rc5+ #251
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430
 memcmp+0xe3/0x160 lib/string.c:861
 strnstr+0x4b/0x70 lib/string.c:934
 __aa_lookupn_ns+0xc1/0x570 security/apparmor/policy_ns.c:209
 aa_lookupn_ns+0x88/0x1e0 security/apparmor/policy_ns.c:240
 aa_fqlookupn_profile+0x1b9/0x1010 security/apparmor/policy.c:468
 fqlookupn_profile+0x80/0xc0 security/apparmor/label.c:1844
 aa_label_strn_parse+0xa3a/0x1230 security/apparmor/label.c:1908
 aa_label_parse+0x42/0x50 security/apparmor/label.c:1943
 aa_change_profile+0x513/0x3510 security/apparmor/domain.c:1362
 apparmor_setprocattr+0xaa4/0x1150 security/apparmor/lsm.c:658
 security_setprocattr+0x66/0xc0 security/security.c:1298
 proc_pid_attr_write+0x301/0x540 fs/proc/base.c:2555
 __vfs_write+0x119/0x9f0 fs/read_write.c:485
 vfs_write+0x1fc/0x560 fs/read_write.c:549
 ksys_write+0x101/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440d49
Code: e8 cc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff237b0228 EFLAGS: 00000213 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440d49
RDX: 0000000000000009 RSI: 0000000020000040 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000001b33880 R11: 0000000000000213 R12: 0000000000008c96
R13: 0000000000401d20 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0006eb63c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 ffffffff06eb0101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801bad8f300: f2 f2 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801bad8f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
>ffff8801bad8f400: f1 f1 f1 f8 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 f2
                   ^
 ffff8801bad8f480: f2 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 f2
 ffff8801bad8f500: f2 f2 f2 00 00 00 00 00 00 00 00 f3 f3 f3 f3 00
==================================================================

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/09/24 04:34 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce
2018/09/24 03:53 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce
2018/09/24 02:11 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce-root
2018/09/24 01:26 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce
2018/09/24 00:06 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce-root
2018/09/23 23:58 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce
2018/09/23 23:51 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce
2018/09/23 23:34 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce-root
2018/09/24 02:11 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce-386
2018/09/24 00:19 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce-386
2018/09/23 23:51 upstream 6bf4ca7fbc85 28d9ac76 .config console log report syz C ci-upstream-kasan-gce-386
2018/09/24 02:10 linux-next 46c163a036b4 28d9ac76 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2018/09/24 01:56 linux-next 46c163a036b4 28d9ac76 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2018/09/23 23:50 linux-next 46c163a036b4 28d9ac76 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.