From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Subject: [patch 2/2 v2] tipc: potential divide by zero in tipc_link_recv_fragment() Date: Mon, 6 May 2013 22:31:17 +0300 Message-ID: <20130506193117.GA11399@elgon.mountain> References: <5187F8BD.1080900@cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Allan Stephens , "David S. Miller" , netdev@vger.kernel.org, tipc-discussion@lists.sourceforge.net, kernel-janitors@vger.kernel.org, Sergei Shtylyov To: Jon Maloy Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:39599 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755232Ab3EFTbe (ORCPT ); Mon, 6 May 2013 15:31:34 -0400 Content-Disposition: inline In-Reply-To: <5187F8BD.1080900@cogentembedded.com> Sender: netdev-owner@vger.kernel.org List-ID: The worry here is that fragm_sz could be zero since it comes from skb->data. Signed-off-by: Dan Carpenter --- v2: fix a whitespace issue diff --git a/net/tipc/link.c b/net/tipc/link.c index 3a6064b3..de94493 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -2524,14 +2524,16 @@ int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb, struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm); u32 msg_sz = msg_size(imsg); u32 fragm_sz = msg_data_sz(fragm); - u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz); + u32 exp_fragm_cnt; u32 max = TIPC_MAX_USER_MSG_SIZE + NAMED_H_SIZE; + if (msg_type(imsg) == TIPC_MCAST_MSG) max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE; - if (msg_size(imsg) > max) { + if (fragm_sz == 0 || msg_size(imsg) > max) { kfree_skb(fbuf); return 0; } + exp_fragm_cnt = msg_sz / fragm_sz + !!(msg_sz % fragm_sz); pbuf = tipc_buf_acquire(msg_size(imsg)); if (pbuf != NULL) { pbuf->next = *pending;