From: Hannes Frederic Sowa Date: Tue, 5 Nov 2013 01:41:27 +0000 (+0100) Subject: ipv6: fix headroom calculation in udp6_ufo_fragment X-Git-Tag: v3.12.4~81 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d68268e60d0ec51e6c269f8dc34bb9fcfee970a7;p=thirdparty%2Fkernel%2Fstable.git ipv6: fix headroom calculation in udp6_ufo_fragment [ Upstream commit 0e033e04c2678dbbe74a46b23fffb7bb918c288e ] Commit 1e2bd517c108816220f262d7954b697af03b5f9c ("udp6: Fix udp fragmentation for tunnel traffic.") changed the calculation if there is enough space to include a fragment header in the skb from a skb->mac_header dervived one to skb_headroom. Because we already peeled off the skb to transport_header this is wrong. Change this back to check if we have enough room before the mac_header. This fixes a panic Saran Neti reported. He used the tbf scheduler which skb_gso_segments the skb. The offsets get negative and we panic in memcpy because the skb was erroneously not expanded at the head. Reported-by: Saran Neti Cc: Pravin B Shelar Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c index 60559511bd9c4..34c6fff3ae848 100644 --- a/net/ipv6/udp_offload.c +++ b/net/ipv6/udp_offload.c @@ -88,7 +88,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, /* Check if there is enough headroom to insert fragment header. */ tnl_hlen = skb_tnl_header_len(skb); - if (skb_headroom(skb) < (tnl_hlen + frag_hdr_sz)) { + if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) { if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz)) goto out; }