fib_trie: Prevent allocating tnode if bits is too big for size_t
This patch adds code to prevent us from attempting to allocate a tnode with
a size larger than what can be represented by size_t.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 08676c5..fae34ad 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -277,6 +277,8 @@
#define TNODE_KMALLOC_MAX \
ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct tnode *))
+#define TNODE_VMALLOC_MAX \
+ ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct tnode *))
static void __node_free_rcu(struct rcu_head *head)
{
@@ -292,8 +294,17 @@
#define node_free(n) call_rcu(&n->rcu, __node_free_rcu)
-static struct tnode *tnode_alloc(size_t size)
+static struct tnode *tnode_alloc(int bits)
{
+ size_t size;
+
+ /* verify bits is within bounds */
+ if (bits > TNODE_VMALLOC_MAX)
+ return NULL;
+
+ /* determine size and verify it is non-zero and didn't overflow */
+ size = TNODE_SIZE(1ul << bits);
+
if (size <= PAGE_SIZE)
return kzalloc(size, GFP_KERNEL);
else
@@ -334,8 +345,7 @@
static struct tnode *tnode_new(t_key key, int pos, int bits)
{
- size_t sz = TNODE_SIZE(1ul << bits);
- struct tnode *tn = tnode_alloc(sz);
+ struct tnode *tn = tnode_alloc(bits);
unsigned int shift = pos + bits;
/* verify bits and pos their msb bits clear and values are valid */