selinux: do not allocate hashtabs dynamically

It is simpler to allocate them statically in the corresponding
structure, avoiding unnecessary kmalloc() calls and pointer
dereferencing.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: manual merging required in policydb.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Author: WOnder93

security/selinux/ss/hashtab.c

@@ -29,34 +29,21 @@ static u32 hashtab_compute_size(u32 nel)
 	return nel == 0 ? 0 : roundup_pow_of_two(nel);
 }
 
-struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, const void *key),
-			       int (*keycmp)(struct hashtab *h, const void *key1, const void *key2),
-			       u32 nel_hint)
+int hashtab_init(struct hashtab *h,
+		 u32 (*hash_value)(struct hashtab *h, const void *key),
+		 int (*keycmp)(struct hashtab *h, const void *key1,
+			       const void *key2),
+		 u32 nel_hint)
 {
-	struct hashtab *p;
-	u32 i, size = hashtab_compute_size(nel_hint);
-
-	p = kzalloc(sizeof(*p), GFP_KERNEL);
-	if (!p)
-		return p;
-
-	p->size = size;
-	p->nel = 0;
-	p->hash_value = hash_value;
-	p->keycmp = keycmp;
-	if (!size)
-		return p;
-
-	p->htable = kmalloc_array(size, sizeof(*p->htable), GFP_KERNEL);
-	if (!p->htable) {
-		kfree(p);
-		return NULL;
-	}
-
-	for (i = 0; i < size; i++)
-		p->htable[i] = NULL;
+	h->size = hashtab_compute_size(nel_hint);
+	h->nel = 0;
+	h->hash_value = hash_value;
+	h->keycmp = keycmp;
+	if (!h->size)
+		return 0;
 
-	return p;
+	h->htable = kcalloc(h->size, sizeof(*h->htable), GFP_KERNEL);
+	return h->htable ? 0 : -ENOMEM;
 }
 
 int hashtab_insert(struct hashtab *h, void *key, void *datum)
@@ -66,7 +53,7 @@ int hashtab_insert(struct hashtab *h, void *key, void *datum)
 
 	cond_resched();
 
-	if (!h || !h->size || h->nel == HASHTAB_MAX_NODES)
+	if (!h->size || h->nel == HASHTAB_MAX_NODES)
 		return -EINVAL;
 
 	hvalue = h->hash_value(h, key);
@@ -102,7 +89,7 @@ void *hashtab_search(struct hashtab *h, const void *key)
 	u32 hvalue;
 	struct hashtab_node *cur;
 
-	if (!h || !h->size)
+	if (!h->size)
 		return NULL;
 
 	hvalue = h->hash_value(h, key);
@@ -121,9 +108,6 @@ void hashtab_destroy(struct hashtab *h)
 	u32 i;
 	struct hashtab_node *cur, *temp;
 
-	if (!h)
-		return;
-
 	for (i = 0; i < h->size; i++) {
 		cur = h->htable[i];
 		while (cur) {
@@ -136,8 +120,6 @@ void hashtab_destroy(struct hashtab *h)
 
 	kfree(h->htable);
 	h->htable = NULL;
-
-	kfree(h);
 }
 
 int hashtab_map(struct hashtab *h,
@@ -148,9 +130,6 @@ int hashtab_map(struct hashtab *h,
 	int ret;
 	struct hashtab_node *cur;
 
-	if (!h)
-		return 0;
-
 	for (i = 0; i < h->size; i++) {
 		cur = h->htable[i];
 		while (cur) {

security/selinux/ss/hashtab.h

@@ -35,14 +35,15 @@ struct hashtab_info {
 };
 
 /*
- * Creates a new hash table with the specified characteristics.
+ * Initializes a new hash table with the specified characteristics.
  *
- * Returns NULL if insufficent space is available or
- * the new hash table otherwise.
+ * Returns -ENOMEM if insufficient space is available or 0 otherwise.
  */
-struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, const void *key),
-			       int (*keycmp)(struct hashtab *h, const void *key1, const void *key2),
-			       u32 nel_hint);
+int hashtab_init(struct hashtab *h,
+		 u32 (*hash_value)(struct hashtab *h, const void *key),
+		 int (*keycmp)(struct hashtab *h, const void *key1,
+			       const void *key2),
+		 u32 nel_hint);
 
 /*
  * Inserts the specified (key, datum) pair into the specified hash table.

security/selinux/ss/mls.c

@@ -165,7 +165,7 @@ int mls_level_isvalid(struct policydb *p, struct mls_level *l)
 
 	if (!l->sens || l->sens > p->p_levels.nprim)
 		return 0;
-	levdatum = hashtab_search(p->p_levels.table,
+	levdatum = hashtab_search(&p->p_levels.table,
 				  sym_name(p, SYM_LEVELS, l->sens - 1));
 	if (!levdatum)
 		return 0;
@@ -293,7 +293,7 @@ int mls_context_to_sid(struct policydb *pol,
 			*(next_cat++) = '\0';
 
 		/* Parse sensitivity. */
-		levdatum = hashtab_search(pol->p_levels.table, sensitivity);
+		levdatum = hashtab_search(&pol->p_levels.table, sensitivity);
 		if (!levdatum)
 			return -EINVAL;
 		context->range.level[l].sens = levdatum->level->sens;
@@ -312,7 +312,7 @@ int mls_context_to_sid(struct policydb *pol,
 				*rngptr++ = '\0';
 			}
 
-			catdatum = hashtab_search(pol->p_cats.table, cur_cat);
+			catdatum = hashtab_search(&pol->p_cats.table, cur_cat);
 			if (!catdatum)
 				return -EINVAL;
 
@@ -325,7 +325,7 @@ int mls_context_to_sid(struct policydb *pol,
 			if (rngptr == NULL)
 				continue;
 
-			rngdatum = hashtab_search(pol->p_cats.table, rngptr);
+			rngdatum = hashtab_search(&pol->p_cats.table, rngptr);
 			if (!rngdatum)
 				return -EINVAL;
 
@@ -458,7 +458,7 @@ int mls_convert_context(struct policydb *oldp,
 		return 0;
 
 	for (l = 0; l < 2; l++) {
-		levdatum = hashtab_search(newp->p_levels.table,
+		levdatum = hashtab_search(&newp->p_levels.table,
 					  sym_name(oldp, SYM_LEVELS,
 						   oldc->range.level[l].sens - 1));
 
@@ -470,7 +470,7 @@ int mls_convert_context(struct policydb *oldp,
 					      node, i) {
 			int rc;
 
-			catdatum = hashtab_search(newp->p_cats.table,
+			catdatum = hashtab_search(&newp->p_cats.table,
 						  sym_name(oldp, SYM_CATS, i));
 			if (!catdatum)
 				return -EINVAL;
@@ -506,7 +506,7 @@ int mls_compute_sid(struct policydb *p,
 		rtr.source_type = scontext->type;
 		rtr.target_type = tcontext->type;
 		rtr.target_class = tclass;
-		r = hashtab_search(p->range_tr, &rtr);
+		r = hashtab_search(&p->range_tr, &rtr);
 		if (r)
 			return mls_range_set(newcontext, r);