From: Jason Wang <jasowang@redhat.com>
To: netdev@vger.kernel.org, davem@davemloft.net,
linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org, mst@redhat.com
Subject: [PATCH] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb()
Date: Wed, 30 May 2012 13:47:02 +0800 [thread overview]
Message-ID: <20120530054702.6146.8503.stgit@amd-6168-8-1.englab.nay.redhat.com> (raw)
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.
Cc: stable@vger.kernel.org [2.6.27+]
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
net/core/sock.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/core/sock.c b/net/core/sock.c
index 653f8c0..4ad5fa5 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1599,6 +1599,7 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
timeo = sock_sndtimeo(sk, noblock);
while (1) {
+ int npages;
err = sock_error(sk);
if (err != 0)
goto failure;
@@ -1607,17 +1608,20 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
if (sk->sk_shutdown & SEND_SHUTDOWN)
goto failure;
+ err = -EMSGSIZE;
+ npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
+ if (npages > MAX_SKB_FRAGS)
+ goto failure;
+
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++) {
next reply other threads:[~2012-05-30 5:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-30 5:47 Jason Wang [this message]
2012-05-30 6:46 ` [PATCH] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb() Eric Dumazet
2012-05-30 7:02 ` David Miller
2012-05-31 6:00 ` Jason Wang
2012-05-31 6:02 ` Michael S. Tsirkin
2012-05-31 6:11 ` Jason Wang
2012-05-31 6:20 ` Eric Dumazet
2012-05-31 6:43 ` Jason Wang
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