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

From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>,
	Paul Moore <paul@paul-moore.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	syzbot <syzbot+21016130b0580a9de3b5@syzkaller.appspotmail.com>,
	tyhicks@canonical.com,
	John Johansen <john.johansen@canonical.com>,
	James Morris <jmorris@namei.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-security-module@vger.kernel.org,
	Serge Hallyn <serge@hallyn.com>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	Jeffrey Vander Stoep <jeffv@google.com>,
	SELinux <selinux@tycho.nsa.gov>,
	Russell Coker <russell@coker.com.au>,
	Laurent Bigonville <bigon@debian.org>,
	syzkaller <syzkaller@googlegroups.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH] LSM: Allow syzbot to ignore security= parameter.
Date: Fri, 1 Feb 2019 22:09:02 +0900	[thread overview]
Message-ID: <52531a69-10ed-d263-be66-e707705597d6@i-love.sakura.ne.jp> (raw)
In-Reply-To: <CACT4Y+Z036bZfN1-_VaQ5EorwFt_tpPm=RTnrYN5qKV_ebgoFw@mail.gmail.com>

On 2019/02/01 19:50, Dmitry Vyukov wrote:
> On Fri, Feb 1, 2019 at 11:44 AM Tetsuo Handa
> <penguin-kernel@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@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@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

