[PATCH 2/3] LSM: SafeSetID: Stop releasing uninitialized ruleset

[John Johansen]

On 9/25/19 2:43 PM, Tyler Hicks wrote:
> From: Micah Morton <mortonm at chromium.org>
> 
> BugLink: https://launchpad.net/bugs/1845391
> 
> The first time a rule set is configured for SafeSetID, we shouldn't be
> trying to release the previously configured ruleset, since there isn't
> one. Currently, the pointer that would point to a previously configured
> ruleset is uninitialized on first rule set configuration, leading to a
> crash when we try to call release_ruleset with that pointer.
> 
> Acked-by: Jann Horn <jannh at google.com>
> Signed-off-by: Micah Morton <mortonm at chromium.org>
> 
> (cherry picked from commit 21ab8580b383f27b7f59b84ac1699cb26d6c3d69)
> Signed-off-by: Tyler Hicks <tyhicks at canonical.com>

Acked-by: John Johansen <john.johnansen at canonical.com>

> ---
>  security/safesetid/securityfs.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/security/safesetid/securityfs.c b/security/safesetid/securityfs.c
> index d568e17dd773..74a13d432ed8 100644
> --- a/security/safesetid/securityfs.c
> +++ b/security/safesetid/securityfs.c
> @@ -187,7 +187,8 @@ static ssize_t handle_policy_update(struct file *file,
>  out_free_buf:
>  	kfree(buf);
>  out_free_pol:
> -	release_ruleset(pol);
> +	if (pol)
> +                release_ruleset(pol);
>  	return err;
>  }
>  
>