4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Florian Westphal fw@strlen.de
don't bother with pathological cases, they only waste cycles. IPv6 requires a minimum MTU of 1280 so we should never see fragments smaller than this (except last frag).
v3: don't use awkward "-offset + len" v2: drop IPv4 part, which added same check w. IPV4_MIN_MTU (68). There were concerns that there could be even smaller frags generated by intermediate nodes, e.g. on radio networks.
Cc: Peter Oskolkov posk@google.com Cc: Eric Dumazet edumazet@google.com Signed-off-by: Florian Westphal fw@strlen.de Signed-off-by: David S. Miller davem@davemloft.net (cherry picked from commit 0ed4229b08c13c84a3c301a08defdc9e7f4467e6) Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/netfilter/nf_conntrack_reasm.c | 4 ++++ net/ipv6/reassembly.c | 4 ++++ 2 files changed, 8 insertions(+)
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c @@ -564,6 +564,10 @@ int nf_ct_frag6_gather(struct net *net, hdr = ipv6_hdr(skb); fhdr = (struct frag_hdr *)skb_transport_header(skb);
+ if (skb->len - skb_network_offset(skb) < IPV6_MIN_MTU && + fhdr->frag_off & htons(IP6_MF)) + return -EINVAL; + skb_orphan(skb); fq = fq_find(net, fhdr->identification, user, hdr, skb->dev ? skb->dev->ifindex : 0); --- a/net/ipv6/reassembly.c +++ b/net/ipv6/reassembly.c @@ -516,6 +516,10 @@ static int ipv6_frag_rcv(struct sk_buff return 1; }
+ if (skb->len - skb_network_offset(skb) < IPV6_MIN_MTU && + fhdr->frag_off & htons(IP6_MF)) + goto fail_hdr; + iif = skb->dev ? skb->dev->ifindex : 0; fq = fq_find(net, fhdr->identification, hdr, iif); if (fq) {