apparmor: Fully initialize aa_perms struct when answering userspace query

Fully initialize the aa_perms struct in profile_query_cb() to avoid the
potential of using an uninitialized struct member's value in a response
to a query from userspace.

Detected by CoverityScan CID#1415126 ("Uninitialized scalar variable")

Fixes: 4f3b3f2 ("apparmor: add profile permission query ability")
Signed-off-by: Tyler Hicks <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Signed-off-by: John Johansen <[email protected]>

Author: tyhicks

security/apparmor/apparmorfs.c

@@ -603,7 +603,7 @@ static const struct file_operations aa_fs_ns_revision_fops = {
 static void profile_query_cb(struct aa_profile *profile, struct aa_perms *perms,
 			     const char *match_str, size_t match_len)
 {
-	struct aa_perms tmp;
+	struct aa_perms tmp = { };
 	struct aa_dfa *dfa;
 	unsigned int state = 0;
 
@@ -613,7 +613,6 @@ static void profile_query_cb(struct aa_profile *profile, struct aa_perms *perms,
 		dfa = profile->file.dfa;
 		state = aa_dfa_match_len(dfa, profile->file.start,
 					 match_str + 1, match_len - 1);
-		tmp = nullperms;
 		if (state) {
 			struct path_cond cond = { };
 
@@ -627,8 +626,6 @@ static void profile_query_cb(struct aa_profile *profile, struct aa_perms *perms,
 					 match_str, match_len);
 		if (state)
 			aa_compute_perms(dfa, state, &tmp);
-		else
-			tmp = nullperms;
 	}
 	aa_apply_modes_to_perms(profile, &tmp);
 	aa_perms_accum_raw(perms, &tmp);