[RFC PATCH 2/3] lsm: correct error codes in security_getselfattr()

[Casey Schaufler]

On 10/24/2023 2:35 PM, Paul Moore wrote:
> We should return -EINVAL if the user specifies LSM_FLAG_SINGLE without
> supplying a valid lsm_ctx struct buffer.
>
> Signed-off-by: Paul Moore <paul at paul-moore.com>

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

> ---
>  security/security.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/security/security.c b/security/security.c
> index 9c63acded4ee..67ded406a5ea 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -3923,9 +3923,9 @@ int security_getselfattr(unsigned int attr, struct lsm_ctx __user *uctx,
>  		/*
>  		 * Only flag supported is LSM_FLAG_SINGLE
>  		 */
> -		if (flags != LSM_FLAG_SINGLE)
> +		if (flags != LSM_FLAG_SINGLE || !uctx)
>  			return -EINVAL;
> -		if (uctx && copy_from_user(&lctx, uctx, sizeof(lctx)))
> +		if (copy_from_user(&lctx, uctx, sizeof(lctx)))
>  			return -EFAULT;
>  		/*
>  		 * If the LSM ID isn't specified it is an error.