[PATCH] LSM: Allow syzbot to ignore security= parameter.

[Tetsuo Handa]

On 2019/02/01 19:50, Dmitry Vyukov wrote:
> On Fri, Feb 1, 2019 at 11:44 AM Tetsuo Handa
> <penguin-kernel at i-love.sakura.ne.jp> wrote:
>>
>> On 2019/02/01 19:09, Dmitry Vyukov wrote:
>>> Thanks for the explanations.
>>>
>>> Here is the change that I've come up with:
>>> https://github.com/google/syzkaller/commit/aa53be276dc84aa8b3825b3416542447ff82b41a
>>
>> You are not going to apply this updated config to upstream kernels now, are you?
>> Removing CONFIG_DEFAULT_SECURITY="apparmor" from configs used by upstream kernels
>> will cause failing to enable AppArmor (unless security=apparmor is specified).
> 
> 
> We do use  security=apparmor, see:
> https://github.com/google/syzkaller/blob/master/dashboard/config/upstream-apparmor.cmdline
> https://github.com/google/syzkaller/blob/master/dashboard/config/upstream-selinux.cmdline
> https://github.com/google/syzkaller/blob/master/dashboard/config/upstream-smack.cmdline
> 

Oh, security= parameter is explicitly specified on all targets?
Then, we can abuse CONFIG_DEBUG_AID_FOR_SYZBOT option. ;-)

LSM folks, may we use this patch for linux-next.git ?
CONFIG_DEBUG_AID_FOR_SYZBOT is a linux-next.git-only kernel config option used by syzbot.



>From c7d21f9c1c0b610ddea4233b89edf7d3140b8baf Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
Date: Fri, 1 Feb 2019 22:03:55 +0900
Subject: [PATCH linux-next] LSM: Allow syzbot to ignore security= parameter.

LSM is going to get infrastructure managed security blob support in Linux
5.1, and it becomes possible to run TOMOYO with SELinux/Smack/AppArmor.
But for compatibility reason, since security= parameter makes it
impossible to run TOMOYO with SELinux/Smack/AppArmor, syzbot can't
test that combination. Therefore, this patch allows syzbot to temporarily
ignore security= parameter. This patch is meant for linux-next.git only,
and will be removed after infrastructure managed security blob support
went to linux.git.

Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
---
 security/security.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/security/security.c b/security/security.c
index ef03643..0632feb 100644
--- a/security/security.c
+++ b/security/security.c
@@ -346,12 +346,14 @@ int __init security_init(void)
 }
 
 /* Save user chosen LSM */
+#ifndef CONFIG_DEBUG_AID_FOR_SYZBOT
 static int __init choose_major_lsm(char *str)
 {
 	chosen_major_lsm = str;
 	return 1;
 }
 __setup("security=", choose_major_lsm);
+#endif
 
 /* Explicitly choose LSM initialization order. */
 static int __init choose_lsm_order(char *str)
-- 
1.8.3.1