From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Thu, 22 Oct 2015 09:10:14 +0000 Subject: [patch] igbvf: integer overflow in igbvf_change_mtu() Message-Id: <20151022091013.GC9202@mwanda> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kernel-janitors@vger.kernel.org The "new_mtu" is between 0 and INT_MAX but when we add ETH_HLEN and ETH_FCS_LEN to it then it could overflow so "max_frame" is negative. We cap the upper bound of "max_frame" but we don't check for negative values. This leads to a static checker warning. Signed-off-by: Dan Carpenter diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c b/drivers/net/ethernet/intel/igbvf/netdev.c index 297af80..fa338e0 100644 --- a/drivers/net/ethernet/intel/igbvf/netdev.c +++ b/drivers/net/ethernet/intel/igbvf/netdev.c @@ -2350,7 +2350,7 @@ static struct net_device_stats *igbvf_get_stats(struct net_device *netdev) static int igbvf_change_mtu(struct net_device *netdev, int new_mtu) { struct igbvf_adapter *adapter = netdev_priv(netdev); - int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN; + unsigned int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN; if (new_mtu < 68 || new_mtu > INT_MAX - ETH_HLEN - ETH_FCS_LEN || max_frame > MAX_JUMBO_FRAME_SIZE)