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KASAN: global-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: global-out-of-bounds in memcmp+0xe3/0x160 lib/string.c:861
Read of size 1 at addr ffffffff88000008 by task syz-executor3/8786

CPU: 0 PID: 8786 Comm: syz-executor3 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+0x58/0x1ff 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
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
 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: 0033:0x457679
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6077a06c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6077a076d4 RCX: 0000000000457679
RDX: 0000000000000009 RSI: 0000000020000040 RDI: 0000000000000005
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d8f38 R14: 00000000004c55ed R15: 0000000000000000

The buggy address belongs to the variable:
 __start_rodata+0x8/0x1000

Memory state around the buggy address:
 ffffffff87ffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffffff87ffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffffff88000000: 00 fa fa fa fa fa fa fa 00 01 fa fa fa fa fa fa
                      ^
 ffffffff88000080: 00 00 00 07 fa fa fa fa 00 04 fa fa fa fa fa fa
 ffffffff88000100: 05 fa fa fa fa fa fa fa 00 00 00 00 05 fa fa fa
==================================================================
CPU: 1 PID: 8817 Comm: syz-executor4 Tainted: G    B             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
 fail_dump lib/fault-inject.c:51 [inline]
 should_fail.cold.4+0xa/0x17 lib/fault-inject.c:149

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/09/23 22:45 upstream 6bf4ca7fbc85 28d9ac76 .config console log report ci-upstream-kasan-gce
* Struck through repros no longer work on HEAD.