[apparmor] [PATCH 07/16] apparmor: internal paths should be treated as disconnected

[Seth Arnold]

On Wed, Apr 20, 2016 at 11:52:49PM -0700, John Johansen wrote:
> Internal mounts are not mounted anywhere and as such should be treated
> as disconnected paths.
> 
> Signed-off-by: John Johansen <john.johansen at canonical.com>

Acked-by: Seth Arnold <seth.arnold at canonical.com>

Thanks

> ---
>  security/apparmor/path.c | 63 +++++++++++++++++++++++++++---------------------
>  1 file changed, 35 insertions(+), 28 deletions(-)
> 
> diff --git a/security/apparmor/path.c b/security/apparmor/path.c
> index bb2f2c6..6b6ab22 100644
> --- a/security/apparmor/path.c
> +++ b/security/apparmor/path.c
> @@ -25,7 +25,6 @@
>  #include "include/path.h"
>  #include "include/policy.h"
>  
> -
>  /* modified from dcache.c */
>  static int prepend(char **buffer, int buflen, const char *str, int namelen)
>  {
> @@ -39,6 +38,37 @@ static int prepend(char **buffer, int buflen, const char *str, int namelen)
>  
>  #define CHROOT_NSCONNECT (PATH_CHROOT_REL | PATH_CHROOT_NSCONNECT)
>  
> +/* If the path is not connected to the expected root,
> + * check if it is a sysctl and handle specially else remove any
> + * leading / that __d_path may have returned.
> + * Unless
> + *     specifically directed to connect the path,
> + * OR
> + *     if in a chroot and doing chroot relative paths and the path
> + *     resolves to the namespace root (would be connected outside
> + *     of chroot) and specifically directed to connect paths to
> + *     namespace root.
> + */
> +static int disconnect(struct path *path, char *buf, char **name, int flags)
> +{
> +	int error = 0;
> +
> +	if (!(flags & PATH_CONNECT_PATH) &&
> +	    !(((flags & CHROOT_NSCONNECT) == CHROOT_NSCONNECT) &&
> +	      our_mnt(path->mnt))) {
> +		/* disconnected path, don't return pathname starting
> +		 * with '/'
> +		 */
> +		error = -EACCES;
> +		if (**name == '/')
> +			*name = *name + 1;
> +	} else if (**name != '/')
> +		/* CONNECT_PATH with missing root */
> +		error = prepend(name, *name - buf, "/", 1);
> +
> +	return error;
> +}
> +
>  /**
>   * d_namespace_path - lookup a name associated with a given path
>   * @path: path to lookup  (NOT NULL)
> @@ -74,7 +104,8 @@ static int d_namespace_path(struct path *path, char *buf, int buflen,
>  			 * control instead of hard coded /proc
>  			 */
>  			return prepend(name, *name - buf, "/proc", 5);
> -		}
> +		} else
> +			return disconnect(path, buf, name, flags);
>  		return 0;
>  	}
>  
> @@ -120,32 +151,8 @@ static int d_namespace_path(struct path *path, char *buf, int buflen,
>  			goto out;
>  	}
>  
> -	/* If the path is not connected to the expected root,
> -	 * check if it is a sysctl and handle specially else remove any
> -	 * leading / that __d_path may have returned.
> -	 * Unless
> -	 *     specifically directed to connect the path,
> -	 * OR
> -	 *     if in a chroot and doing chroot relative paths and the path
> -	 *     resolves to the namespace root (would be connected outside
> -	 *     of chroot) and specifically directed to connect paths to
> -	 *     namespace root.
> -	 */
> -	if (!connected) {
> -		if (!(flags & PATH_CONNECT_PATH) &&
> -			   !(((flags & CHROOT_NSCONNECT) == CHROOT_NSCONNECT) &&
> -			     our_mnt(path->mnt))) {
> -			/* disconnected path, don't return pathname starting
> -			 * with '/'
> -			 */
> -			error = -EACCES;
> -			if (*res == '/')
> -				*name = res + 1;
> -		} else if (*res != '/')
> -			/* CONNECT_PATH with missing root */
> -			error = prepend(name, *name - buf, "/", 1);
> -
> -	}
> +	if (!connected)
> +		error = disconnect(path, buf, name, flags);
>  
>  out:
>  	return error;
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