kernel panic: MAC Initialization failed. (3)

kernel panic: MAC Initialization failed. (3)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    42fd8df9d1d9 Add linux-next specific files for 20190228
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=179e9b6cc00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c0f38652d28b522f
dashboard link: https://syzkaller.appspot.com/bug?extid=2ee3f8974c2e7dc69feb
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14c68242c00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17190c8ac00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2ee3f8974c2e7dc69feb@syzkaller.appspotmail.com

RIP: 0033:0x440fe9
Code: e8 0c ad 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:00007ffc37062bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000440fe9
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007ffc37062bf0 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
ERROR: Out of memory at tomoyo_realpath_from_path.
Kernel panic - not syncing: MAC Initialization failed.
CPU: 0 PID: 7764 Comm: syz-executor980 Not tainted 5.0.0-rc8-next-20190228  
#45
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+0x172/0x1f0 lib/dump_stack.c:113
  panic+0x2cb/0x65c kernel/panic.c:214
  tomoyo_warn_oom.cold+0x35/0x43 security/tomoyo/memory.c:28
  tomoyo_realpath_from_path+0x3a8/0x730 security/tomoyo/realpath.c:320
  tomoyo_realpath_nofollow+0xc8/0xdb security/tomoyo/realpath.c:336
  tomoyo_find_next_domain+0x28c/0x1f8a security/tomoyo/domain.c:725
  tomoyo_bprm_check_security security/tomoyo/tomoyo.c:107 [inline]
  tomoyo_bprm_check_security+0x12a/0x1b0 security/tomoyo/tomoyo.c:97
  security_bprm_check+0x69/0xb0 security/security.c:751
  search_binary_handler+0x77/0x570 fs/exec.c:1644
  exec_binprm fs/exec.c:1698 [inline]
  __do_execve_file.isra.0+0x1394/0x23f0 fs/exec.c:1818
  do_execveat_common fs/exec.c:1865 [inline]
  do_execveat fs/exec.c:1893 [inline]
  __do_sys_execveat fs/exec.c:1969 [inline]
  __se_sys_execveat fs/exec.c:1961 [inline]
  __x64_sys_execveat+0xed/0x130 fs/exec.c:1961
  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440fe9
Code: e8 0c ad 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:00007ffc37062bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000440fe9
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007ffc37062bf0 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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Re: kernel panic: MAC Initialization failed. (3)

[syzbot]

syzbot has bisected this bug to:

commit 89a9684ea158dd7eef1728be9f0aed9a7d41cf19
Author: Kees Cook <keescook@chromium.org>
Date:   Tue Feb 12 18:23:18 2019 +0000

     LSM: Ignore "security=" when "lsm=" is specified

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11572723200000
start commit:   89a9684e LSM: Ignore "security=" when "lsm=" is specified
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=13572723200000
console output: https://syzkaller.appspot.com/x/log.txt?x=15572723200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c0f38652d28b522f
dashboard link: https://syzkaller.appspot.com/bug?extid=2ee3f8974c2e7dc69feb
userspace arch: amd64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14c68242c00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17190c8ac00000

Reported-by: syzbot+2ee3f8974c2e7dc69feb@syzkaller.appspotmail.com
Fixes: 89a9684e ("LSM: Ignore "security=" when "lsm=" is specified")

Re: kernel panic: MAC Initialization failed. (3)

[Tetsuo Handa]

F.Y.I. Nothing is wrong with that commit. That commit merely allows enabling TOMOYO and
one of SELinux/Smack/AppArmor at the same time for syzbot's kernel command line options.
This problem will be handled by a patch at
https://lore.kernel.org/linux-security-module/1551362770-8655-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp/
and then updating syzbot to build kernels with this option enabled.

Well, it is wonderful that syzbot started bisecting. ;-)

On 2019/03/11 22:26, syzbot wrote:
> syzbot has bisected this bug to:
> 
> commit 89a9684ea158dd7eef1728be9f0aed9a7d41cf19
> Author: Kees Cook <keescook@chromium.org>
> Date:   Tue Feb 12 18:23:18 2019 +0000
> 
>     LSM: Ignore "security=" when "lsm=" is specified
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11572723200000
> start commit:   89a9684e LSM: Ignore "security=" when "lsm=" is specified
> git tree:       linux-next
> final crash:    https://syzkaller.appspot.com/x/report.txt?x=13572723200000
> console output: https://syzkaller.appspot.com/x/log.txt?x=15572723200000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c0f38652d28b522f
> dashboard link: https://syzkaller.appspot.com/bug?extid=2ee3f8974c2e7dc69feb
> userspace arch: amd64
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14c68242c00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17190c8ac00000
> 
> Reported-by: syzbot+2ee3f8974c2e7dc69feb@syzkaller.appspotmail.com
> Fixes: 89a9684e ("LSM: Ignore "security=" when "lsm=" is specified")
>