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authorJason Wang <jasowang@redhat.com>2012-05-30 21:18:10 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-16 09:03:43 -0700
commit31fab24bd9cdb9733383cbf9732cda1649f2a760 (patch)
tree993b299b55863aa2f4a2f3741cbb1eef3ee0cd54 /net
parent4f4bdaeb40df95499c1ee7ea3fbca9d76174a59e (diff)
net: sock: validate data_len before allocating skb in sock_alloc_send_pskb()
[ Upstream commit cc9b17ad29ecaa20bfe426a8d4dbfb94b13ff1cc ] We need to validate the number of pages consumed by data_len, otherwise frags array could be overflowed by userspace. So this patch validate data_len and return -EMSGSIZE when data_len may occupies more frags than MAX_SKB_FRAGS. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/sock.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index b2e14c07d92..0f8402ea434 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1600,6 +1600,11 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
gfp_t gfp_mask;
long timeo;
int err;
+ int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
+
+ err = -EMSGSIZE;
+ if (npages > MAX_SKB_FRAGS)
+ goto failure;
gfp_mask = sk->sk_allocation;
if (gfp_mask & __GFP_WAIT)
@@ -1618,14 +1623,12 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
if (atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) {
skb = alloc_skb(header_len, gfp_mask);
if (skb) {
- int npages;
int i;
/* No pages, we're done... */
if (!data_len)
break;
- npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
skb->truesize += data_len;
skb_shinfo(skb)->nr_frags = npages;
for (i = 0; i < npages; i++) {