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Commit a8444b1c authored by Florian Westphal's avatar Florian Westphal Committed by Greg Kroah-Hartman
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ipv6: defrag: drop non-last frags smaller than min mtu 



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: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
(cherry picked from commit 0ed4229b08c13c84a3c301a08defdc9e7f4467e6)
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 87169595

net/ipv6/netfilter/nf_conntrack_reasm.c

+4 −0
Original line number Diff line number Diff line
@@ -564,6 +564,10 @@ int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) 
	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);

net/ipv6/reassembly.c

+4 −0
Original line number Diff line number Diff line
@@ -516,6 +516,10 @@ static int ipv6_frag_rcv(struct sk_buff *skb) 
		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) {