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authorFlorian Westphal <fw@strlen.de>2018-08-03 02:22:20 +0200
committerDavid S. Miller <davem@davemloft.net>2018-08-05 17:21:14 -0700
commit0ed4229b08c13c84a3c301a08defdc9e7f4467e6 (patch)
tree25ed6930db15e9d4150afaaf7ad46467c496feb1 /net/ipv6
parentc30f1fc041b74ecdb072dd44f858750414b8b19f (diff)
downloadlinux-0ed4229b08c13c84a3c301a08defdc9e7f4467e6.tar.bz2
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: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/netfilter/nf_conntrack_reasm.c4
-rw-r--r--net/ipv6/reassembly.c4
2 files changed, 8 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 38d69ef516d5..2a14d8b65924 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -558,6 +558,10 @@ 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);
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index b4e558ab39fa..5c5b4f79296e 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -456,6 +456,10 @@ 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) {