Re: [PATCH v3 3/8] block: use new capable_any functionality

From: Bart Van Assche <bvanassche@acm.org>
To: "Christian Göttsche" <cgzones@googlemail.com>, selinux@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>, Serge Hallyn <serge@hallyn.com>,
	Alistair Delva <adelva@google.com>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: Re: [PATCH v3 3/8] block: use new capable_any functionality
Date: Wed, 15 Jun 2022 20:00:17 -0700	[thread overview]
Message-ID: <7fd6f544-0bd2-62fe-bddd-869364f351e8@acm.org> (raw)
In-Reply-To: <20220615152623.311223-2-cgzones@googlemail.com>

On 6/15/22 08:26, Christian Göttsche wrote:
> Use the new added capable_any function in appropriate cases, where a
> task is required to have any of two capabilities.
> 
> Reorder CAP_SYS_ADMIN last.
> 
> Fixes: 94c4b4fd25e6 ("block: Check ADMIN before NICE for IOPRIO_CLASS_RT")
> 
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> ---
> v3:
>     rename to capable_any()
> ---
>   block/ioprio.c | 9 +--------
>   1 file changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/block/ioprio.c b/block/ioprio.c
> index 2fe068fcaad5..6441c052f837 100644
> --- a/block/ioprio.c
> +++ b/block/ioprio.c
> @@ -37,14 +37,7 @@ int ioprio_check_cap(int ioprio)
>   
>   	switch (class) {
>   		case IOPRIO_CLASS_RT:
> -			/*
> -			 * Originally this only checked for CAP_SYS_ADMIN,
> -			 * which was implicitly allowed for pid 0 by security
> -			 * modules such as SELinux. Make sure we check
> -			 * CAP_SYS_ADMIN first to avoid a denial/avc for
> -			 * possibly missing CAP_SYS_NICE permission.
> -			 */
> -			if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_NICE))
> +			if (!capable_any(CAP_SYS_NICE, CAP_SYS_ADMIN))
>   				return -EPERM;
>   			fallthrough;
>   			/* rt has prio field too */

Reviewed-by: Bart Van Assche <bvanassche@acm.org>