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fib_trie: Prevent allocating tnode if bits is too big for size_t

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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>
This commit is contained in:
Alexander Duyck 2015-03-04 15:04:46 -08:00 committed by David S. Miller
parent 71e8b67d0f
commit 1de3d87bcd
1 changed files with 13 additions and 3 deletions
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16
net/ipv4/fib_trie.c
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@ -277,6 +277,8 @@ static inline void alias_free_mem_rcu(struct fib_alias *fa)
#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 @@ static void __node_free_rcu(struct rcu_head *head)
#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 *leaf_new(t_key key, struct fib_alias *fa)
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 */