Re: mount.nfs: Protocol error after upgrade to linux/master

[Casey Schaufler <casey@schaufler-ca.com>]

On 3/19/2019 3:56 AM, Tetsuo Handa wrote:
> Since Kees Cook seems to be busy now, here is my version...
>
>  From 885553e4793d9af2d4e9e99c7d137b0ec7b5f8ad Mon Sep 17 00:00:00 2001
> From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Date: Tue, 19 Mar 2019 19:52:31 +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@netronome.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Acked-by: Casey Schaufler <casey@schaufler-ca.com>


> ---
>   security/Kconfig | 36 +++++++++++++++++++++++++++++++++++-
>   1 file changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/security/Kconfig b/security/Kconfig
> index 1d6463f..743e594 100644
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -239,9 +239,43 @@ 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 +	prompt "Default security module [superseded by 'Ordered list of enabled LSMs' below]"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