LSM: Check for NULL cred-security on free

commit a5795fd38e upstream.

From: Casey Schaufler <casey@schaufler-ca.com>

Check that the cred security blob has been set before trying
to clean it up. There is a case during credential initialization
that could result in this.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Reported-by: syzbot+69ca07954461f189e808@syzkaller.appspotmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
James Morris 2019-01-16 15:41:11 -08:00 committed by Greg Kroah-Hartman
parent 993e65a624
commit b9f9379336

View File

@ -993,6 +993,13 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp)
void security_cred_free(struct cred *cred)
{
/*
* There is a failure case in prepare_creds() that
* may result in a call here with ->security being NULL.
*/
if (unlikely(cred->security == NULL))
return;
call_void_hook(cred_free, cred);
}