3 files changed, 45 insertions, 6 deletions
diff --git a/security/apparmor/include/lib.h b/security/apparmor/include/lib.h
index e60bfa410e55db..200cf36c5e0a14 100644
--- a/security/apparmor/include/lib.h
+++ b/security/apparmor/include/lib.h
@@ -125,6 +125,7 @@ struct aa_str_table {
 };
 
 void aa_free_str_table(struct aa_str_table *table);
+bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp);
 
 struct counted_str {
 	struct kref count;
diff --git a/security/apparmor/lib.c b/security/apparmor/lib.c
index 7cdf430762a8f1..f51e79cc36d4d1 100644
--- a/security/apparmor/lib.c
+++ b/security/apparmor/lib.c
@@ -116,6 +116,29 @@ int aa_print_debug_params(char *buffer)
 			       aa_g_debug);
 }
 
+bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp)
+{
+	char **n;
+	int i;
+
+	if (t->size == newsize)
+		return true;
+	n = kcalloc(newsize, sizeof(*n), gfp);
+	if (!n)
+		return false;
+	for (i = 0; i < min(t->size, newsize); i++)
+		n[i] = t->table[i];
+	for (; i < t->size; i++)
+		kfree_sensitive(t->table[i]);
+	if (newsize > t->size)
+		memset(&n[t->size], 0, (newsize-t->size)*sizeof(*n));
+	kfree_sensitive(t->table);
+	t->table = n;
+	t->size = newsize;
+
+	return true;
+}
+
 /**
  * aa_free_str_table - free entries str table
  * @t: the string table to free  (MAYBE NULL)
diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
index 588dd1d5d36454..58c106b63727ea 100644
--- a/security/apparmor/policy_unpack.c
+++ b/security/apparmor/policy_unpack.c
@@ -802,8 +802,12 @@ static int unpack_pdb(struct aa_ext *e, struct aa_policydb **policy,
 	if (!pdb->dfa && pdb->trans.table)
 		aa_free_str_table(&pdb->trans);
 
-	/* TODO: move compat mapping here, requires dfa merging first */
-	/* TODO: move verify here, it has to be done after compat mappings */
+	/* TODO:
+	 * - move compat mapping here, requires dfa merging first
+	 * - move verify here, it has to be done after compat mappings
+	 * - move free of unneeded trans table here, has to be done
+	 *   after perm mapping.
+	 */
 out:
 	*policy = pdb;
 	return 0;
@@ -1242,21 +1246,32 @@ static bool verify_perm(struct aa_perms *perm)
 static bool verify_perms(struct aa_policydb *pdb)
 {
 	int i;
+	int xidx, xmax = -1;
 
 	for (i = 0; i < pdb->size; i++) {
 		if (!verify_perm(&pdb->perms[i]))
 			return false;
 		/* verify indexes into str table */
-		if ((pdb->perms[i].xindex & AA_X_TYPE_MASK) == AA_X_TABLE &&
-		    (pdb->perms[i].xindex & AA_X_INDEX_MASK) >= pdb->trans.size)
-			return false;
+		if ((pdb->perms[i].xindex & AA_X_TYPE_MASK) == AA_X_TABLE) {
+			xidx = pdb->perms[i].xindex & AA_X_INDEX_MASK;
+			if (xidx >= pdb->trans.size)
+				return false;
+			if (xmax < xidx)
+				xmax = xidx;
+		}
 		if (pdb->perms[i].tag && pdb->perms[i].tag >= pdb->trans.size)
 			return false;
 		if (pdb->perms[i].label &&
 		    pdb->perms[i].label >= pdb->trans.size)
 			return false;
 	}
-
+	/* deal with incorrectly constructed string tables */
+	if (xmax == -1) {
+		aa_free_str_table(&pdb->trans);
+	} else if (pdb->trans.size > xmax + 1) {
+		if (!aa_resize_str_table(&pdb->trans, xmax + 1, GFP_KERNEL))
+			return false;
+	}
 	return true;
 }