From: Florian Westphal <fw@xxxxxxxxx>
[ Upstream commit 0ed4229b08c13c84a3c301a08defdc9e7f4467e6 ]
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@xxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Mao Wenan <maowenan@xxxxxxxxxx>
---
net/ipv6/netfilter/nf_conntrack_reasm.c | 4 ++++
net/ipv6/reassembly.c | 4 ++++
2 files changed, 8 insertions(+)
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 9cd8863..c5033a2 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -602,6 +602,10 @@ struct sk_buff *nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 use
hdr = ipv6_hdr(clone);
fhdr = (struct frag_hdr *)skb_transport_header(clone);
+ 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->saddr, &hdr->daddr,
skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index adc7512..44c7f4c 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -549,6 +549,10 @@ 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;
+
fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
if (fq) {
--
1.8.3.1
