Re: [PATCH 3/3][RFC] SELinux: don't check permissions for kernel mounts

[Stephen Smalley <sds@tycho.nsa.gov>]

On Fri, 2008-12-19 at 12:07 +1100, James Morris wrote:
> Don't bother checking permissions when the kernel performs an internal 
> mount, as this should always be allowed.
> 
> Signed-off-by: James Morris <jmorris@namei.org>

Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>

> ---
>  security/selinux/hooks.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 3897758..4a44903 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2461,6 +2461,10 @@ static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
>  	if (rc)
>  		return rc;
>  
> +	/* Allow all mounts performed by the kernel */
> +	if (flags & MS_KERNMOUNT)
> +		return 0;
> +
>  	AVC_AUDIT_DATA_INIT(&ad, FS);
>  	ad.u.fs.path.dentry = sb->s_root;
>  	return superblock_has_perm(current, sb, FILESYSTEM__MOUNT, &ad);
-- 
Stephen Smalley
National Security Agency


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