linux-kernel - Re: Linux 5.1-rc2

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Message-ID: <8811b2e4-28e1-2f01-024b-fb7d0196483f@i-love.sakura.ne.jp>
Date:   Tue, 26 Mar 2019 06:05:51 +0900
From:   Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
To:     James Morris <jmorris@...ei.org>,
        Randy Dunlap <rdunlap@...radead.org>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        linux-security-module <linux-security-module@...r.kernel.org>,
        Kees Cook <keescook@...omium.org>
Subject: Re: Linux 5.1-rc2

On 2019/03/26 4:08, James Morris wrote:
> On Sun, 24 Mar 2019, Randy Dunlap wrote:
> 
>> On 3/24/19 2:26 PM, Linus Torvalds wrote:
>>> Well, we're a week away from the merge window close, and here's rc2.
>>> Things look fairly normal, but honestly, rc2 is usually too early to
>>> tell.  People haven't necessarily had time to notice problems yet.
>>> Which is just another way of saying "please test harder".
>>>
>>> Nothing particularly stands out. Yes, we had some fixes for the new
>>> io_ring code for issues that were discussed when merging it. Other
>>> than that, worth noting is that the bulk of the patches are for
>>> tooling, not the core kernel. In fact, about two thirds of the patch
>>> is just for the tools/ subdirectory, most of it due to some late perf
>>> tool updates. The people involved promise they're done.
>>
>> Hmph.  I'm still looking for the patch that restores the various
>> CONFIG_DEFAULT_<security> kconfig options to be merged.
>>
>> https://lore.kernel.org/linux-security-module/2bf23acd-22c4-a260-7648-845887a409d5@i-love.sakura.ne.jp/
>>
>> since commit 70b62c25665f636c9f6c700b26af7df296b0887e dropped them somehow.
> 
> AFAICT we don't have a finalized version of the patch yet.
> 
> Kees?
> 

As far as I can tell, Kees's comment

  It breaks the backward-compat for the "security=" line. If a system is
  booted with CONFIG_LSM="minors...,apparmor" and "security=selinux",
  neither apparmor nor selinux will be initialized. The logic on
  "security=..." depends on the other LSMs being present in the list.

was just a confusion, and I think that this version can become
the finalized version.

>From 72f5f21b800c87f9ec3600f6e3acfb654690d8f0 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Date: Tue, 26 Mar 2019 05:56:30 +0900
Subject: [PATCH] LSM: Revive CONFIG_DEFAULT_SECURITY_* for "make oldconfig"

Commit 70b62c25665f636c ("LoadPin: Initialize as ordered LSM") removed
CONFIG_DEFAULT_SECURITY_{SELINUX,SMACK,TOMOYO,APPARMOR,DAC} from
security/Kconfig and changed CONFIG_LSM to provide a fixed ordering as a
default value. That commit expected that existing users (upgrading from
Linux 5.0 and earlier) will edit CONFIG_LSM value in accordance with
their CONFIG_DEFAULT_SECURITY_* choice in their old kernel configs. But
since users might forget to edit CONFIG_LSM value, this patch revives
the choice (only for providing the default value for CONFIG_LSM) in order
to make sure that CONFIG_LSM reflects CONFIG_DEFAULT_SECURITY_* from their
old kernel configs.

Reported-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
Signed-off-by: Kees Cook <keescook@...omium.org>
Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Acked-by: Casey Schaufler <casey@...aufler-ca.com>
---
 security/Kconfig | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/security/Kconfig b/security/Kconfig
index 1d6463f..2f29805 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -239,9 +239,44 @@ source "security/safesetid/Kconfig"
 
 source "security/integrity/Kconfig"
 
+choice
+	prompt "Default security module [superseded by 'Ordered list of enabled LSMs' below]"
+	default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
+	default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
+	default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
+	default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
+	default DEFAULT_SECURITY_DAC
+
+	help
+	  This choice is there only for converting CONFIG_DEFAULT_SECURITY in old
+	  kernel config to CONFIG_LSM in new kernel config. Don't change this choice
+	  unless you are creating a fresh kernel config, for this choice will be
+	  ignored after CONFIG_LSM is once defined.
+
+	config DEFAULT_SECURITY_SELINUX
+		bool "SELinux" if SECURITY_SELINUX=y
+
+	config DEFAULT_SECURITY_SMACK
+		bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
+
+	config DEFAULT_SECURITY_TOMOYO
+		bool "TOMOYO" if SECURITY_TOMOYO=y
+
+	config DEFAULT_SECURITY_APPARMOR
+		bool "AppArmor" if SECURITY_APPARMOR=y
+
+	config DEFAULT_SECURITY_DAC
+		bool "Unix Discretionary Access Controls"
+
+endchoice
+
 config LSM
 	string "Ordered list of enabled LSMs"
-	default "yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
+	default "yama,loadpin,safesetid,integrity,selinux" if DEFAULT_SECURITY_SELINUX
+	default "yama,loadpin,safesetid,integrity,smack" if DEFAULT_SECURITY_SMACK
+	default "yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO
+	default "yama,loadpin,safesetid,integrity,apparmor" if DEFAULT_SECURITY_APPARMOR
+	default "yama,loadpin,safesetid,integrity"
 	help
 	  A comma-separated list of LSMs, in initialization order.
 	  Any LSMs left off this list will be ignored. This can be
-- 
1.8.3.1