From 23d6f8dd1cc9ca2a3aaed9c6bb24f80b39e071df Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Tue, 1 Oct 2013 11:33:59 +0200 Subject: ip_tunnel: Fix a memory corruption in ip_tunnel_xmit [ Upstream commit 3e08f4a72f689c6296d336c2aab4bddd60c93ae2 ] We might extend the used aera of a skb beyond the total headroom when we install the ipip header. Fix this by calling skb_cow_head() unconditionally. Bug was introduced with commit c544193214 ("GRE: Refactor GRE tunneling code.") Cc: Pravin Shelar Signed-off-by: Steffen Klassert Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_tunnel.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'net') diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index b7a4c21c06ec..92d2f0f5d7bf 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -659,13 +659,13 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr) + rt->dst.header_len; - if (max_headroom > dev->needed_headroom) { + if (max_headroom > dev->needed_headroom) dev->needed_headroom = max_headroom; - if (skb_cow_head(skb, dev->needed_headroom)) { - dev->stats.tx_dropped++; - dev_kfree_skb(skb); - return; - } + + if (skb_cow_head(skb, dev->needed_headroom)) { + dev->stats.tx_dropped++; + dev_kfree_skb(skb); + return; } skb_dst_drop(skb); -- cgit v1.2.3