From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759458Ab2GLWgx (ORCPT ); Thu, 12 Jul 2012 18:36:53 -0400 Received: from mail-gh0-f174.google.com ([209.85.160.174]:63423 "EHLO mail-gh0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759418Ab2GLWgi (ORCPT ); Thu, 12 Jul 2012 18:36:38 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jason Wang , "David S. Miller" Subject: [ 019/187] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb() Date: Thu, 12 Jul 2012 15:32:55 -0700 Message-Id: <20120712191524.033547504@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712191522.742634173@linuxfoundation.org> References: <20120712192421.GA28926@kroah.com> <20120712191522.742634173@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang [ 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/sock.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1600,6 +1600,11 @@ struct sk_buff *sock_alloc_send_pskb(str 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(str 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++) {