Bugzilla: 1030015 1030017 Upstream-status: 3.13 From aeb45260747b0a1bf4d374d5e65298cc254cb4f5 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Tue, 5 Nov 2013 02:41:27 +0100 Subject: [PATCH] ipv6: fix headroom calculation in udp6_ufo_fragment 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 --- net/ipv6/udp_offload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c index 5d1b8d7..657914b 100644 --- a/net/ipv6/udp_offload.c +++ b/net/ipv6/udp_offload.c @@ -86,7 +86,7 @@ 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; } -- 1.8.3.1