apparmor: fix oops in profile_unpack() when policy_db is not present

BugLink: http://bugs.launchpad.net/bugs/1592547

If unpack_dfa() returns NULL due to the dfa not being present,
profile_unpack() is not checking if the dfa is not present (NULL).

Signed-off-by: John Johansen <john.johansen@canonical.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
index 951ae4633979..b9b1c66a32a5 100644
--- a/security/apparmor/policy_unpack.c
+++ b/security/apparmor/policy_unpack.c
@@ -583,6 +583,9 @@ static struct aa_profile *unpack_profile(struct aa_ext *e)
                         error = PTR_ERR(profile->policy.dfa);
                         profile->policy.dfa = NULL;
                         goto fail;
+                } else if (!profile->policy.dfa) {
+                        error = -EPROTO;
+                        goto fail;
                 }
                 if (!unpack_u32(e, &profile->policy.start[0], "start"))
                         /* default start state */