From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: [PATCH] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb() To: netdev@vger.kernel.org, davem@davemloft.net, linux-kernel@vger.kernel.org From: Jason Wang Cc: stable@vger.kernel.org, mst@redhat.com Date: Wed, 30 May 2012 13:47:02 +0800 Message-ID: <20120530054702.6146.8503.stgit@amd-6168-8-1.englab.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: 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 --- 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++) {