diff options
| author | Vasily Averin <vvs@virtuozzo.com> | 2017-07-14 12:04:16 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-07-15 14:38:31 -0700 |
| commit | 254d900b801fc04aa524ff7bafe28fdd1dbf0ed6 (patch) | |
| tree | 55a0227c8bebc7c9ec2c375a42ad61f4f6eafba6 /net | |
| parent | e36fef66f4bbe8a51e8f8334a058a42c0f16e373 (diff) | |
ipv4: ip_do_fragment: fix headroom tests
Some time ago David Woodhouse reported skb_under_panic
when we try to push ethernet header to fragmented ipv6 skbs.
It was fixed for ipv6 by Florian Westphal in
commit 1d325d217c7f ("ipv6: ip6_fragment: fix headroom tests and skb leak")
However similar problem still exist in ipv4.
It does not trigger skb_under_panic due paranoid check
in ip_finish_output2, however according to Alexey Kuznetsov
current state is abnormal and ip_fragment should be fixed too.
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/ip_output.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 7eb252dcecee..50c74cd890bc 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -599,6 +599,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, hlen = iph->ihl * 4; mtu = mtu - hlen; /* Size of data space */ IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; + ll_rs = LL_RESERVED_SPACE(rt->dst.dev); /* When frag_list is given, use it. First, check its validity: * some transformers could create wrong frag_list or break existing @@ -614,14 +615,15 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, if (first_len - hlen > mtu || ((first_len - hlen) & 7) || ip_is_fragment(iph) || - skb_cloned(skb)) + skb_cloned(skb) || + skb_headroom(skb) < ll_rs) goto slow_path; skb_walk_frags(skb, frag) { /* Correct geometry. */ if (frag->len > mtu || ((frag->len & 7) && frag->next) || - skb_headroom(frag) < hlen) + skb_headroom(frag) < hlen + ll_rs) goto slow_path_clean; /* Partially cloned skb? */ @@ -711,8 +713,6 @@ slow_path: left = skb->len - hlen; /* Space per frame */ ptr = hlen; /* Where to start from */ - ll_rs = LL_RESERVED_SPACE(rt->dst.dev); - /* * Fragment the datagram. */ |