From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [V2 PATCH] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb() Date: Thu, 31 May 2012 15:18:10 +0800 Message-ID: <20120531071809.6392.26677.stgit@amd-6168-8-1.englab.nay.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: stable@vger.kernel.org To: netdev@vger.kernel.org, edumazet@google.com, mst@redhat.com, davem@davemloft.net, linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index 653f8c0..9e5b71f 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1592,6 +1592,11 @@ 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) @@ -1610,14 +1615,12 @@ 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++) {