[PATCH 4/7] fscrypt: fix dereference of NULL user_key_payload

[James Morris]

On Thu, 28 Sep 2017, Eric Biggers wrote:

> From: Eric Biggers <ebiggers at google.com>
> 
> When an fscrypt-encrypted file is opened, we request the file's master
> key from the keyrings service as a logon key, then access its payload.
> However, a revoked key has a NULL payload, and we failed to check for
> this.  request_key() *does* skip revoked keys, but there is still a
> window where the key can be revoked before we acquire its semaphore.
> 
> Fix it by checking for a NULL payload, treating it like a key which was
> already revoked at the time it was requested.
> 
> Fixes: 88bd6ccdcdd6 ("ext4 crypto: add encryption key management facilities")
> Cc: <stable at vger.kernel.org>    [v4.1+]
> Signed-off-by: Eric Biggers <ebiggers at google.com>


Reviewed-by: James Morris <james.l.morris at oracle.com>


-- 
James Morris
<jmorris at namei.org>

--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html