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Subject: Re: [PATCH] LSM: Ignore "security=" when "lsm=" is specified
To:     Kees Cook <keescook@chromium.org>, James Morris <jmorris@namei.org>
Cc:     linux-security-module@vger.kernel.org,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        linux-kernel@vger.kernel.org
References: <20190211225403.GA7769@beast>
From:   Casey Schaufler <casey@schaufler-ca.com>
Message-ID: <74310e83-a258-e9c0-7d98-8b2cc5ced3a4@schaufler-ca.com>
Date:   Mon, 11 Feb 2019 15:10:20 -0800
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On 2/11/2019 2:54 PM, Kees Cook wrote:
> To avoid potential confusion, explicitly ignore "security=" when "lsm=" is
> used on the command line, and report that it is happening.
>
> Suggested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  security/security.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/security/security.c b/security/security.c
> index 3147785e20d7..e6153ed54361 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -288,9 +288,13 @@ static void __init ordered_lsm_init(void)
>  	ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms),
>  				GFP_KERNEL);
>  
> -	if (chosen_lsm_order)
> +	if (chosen_lsm_order) {
> +		if (chosen_major_lsm) {
> +			pr_info("security= is ignored because of lsm=\n");

This is a little awkward. How about "lsm= supersedes security=".

> +			chosen_major_lsm = NULL;
> +		}
>  		ordered_lsm_parse(chosen_lsm_order, "cmdline");
> -	else
> +	} else
>  		ordered_lsm_parse(builtin_lsm_order, "builtin");
>  
>  	for (lsm = ordered_lsms; *lsm; lsm++)