From: Mao Wenan <maowenan@huawei.com>
To: <gregkh@linux-foundation.org>, <stable@vger.kernel.org>,
<edumazet@google.com>, <netdev@vger.kernel.org>,
<davem@davemloft.net>, <maowenan@huawei.com>,
<eric.dumazet@gmail.com>
Subject: [PATCH stable 4.4 v2 06/11] ipv6: defrag: drop non-last frags smaller than min mtu
Date: Fri, 25 Jan 2019 10:48:39 +0800 [thread overview]
Message-ID: <1548384524-174152-7-git-send-email-maowenan@huawei.com> (raw)
In-Reply-To: <1548384524-174152-1-git-send-email-maowenan@huawei.com>
From: Florian Westphal <fw@strlen.de>
[ 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@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>
Signed-off-by: Mao Wenan <maowenan@huawei.com>
---
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..88bfae1 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))
+ goto ret_orig;
+
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
next prev parent reply other threads:[~2019-01-25 2:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-25 2:48 [PATCH stable 4.4 v2 00/11] fix FragmentSmack in stable branch (CVE-2018-5391) Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 01/11] net: speed up skb_rbtree_purge() Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 02/11] ip: discard IPv4 datagrams with overlapping segments Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 03/11] net: modify skb_rbtree_purge to return the truesize of all purged skbs Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 04/11] inet: frags: get rif of inet_frag_evicting() Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 05/11] ip: use rb trees for IP frag queue Mao Wenan
2019-01-25 2:48 ` Mao Wenan [this message]
2019-01-25 2:48 ` [PATCH stable 4.4 v2 07/11] ip: add helpers to process in-order fragments faster Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 08/11] ip: process in-order fragments efficiently Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 09/11] net: ipv4: do not handle duplicate fragments as overlapping Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 10/11] ip: frags: fix crash in ip_do_fragment() Mao Wenan
2019-01-25 2:48 ` [PATCH stable 4.4 v2 11/11] ipv4: frags: precedence bug in ip_expire() Mao Wenan
2019-02-04 10:03 ` [PATCH stable 4.4 v2 00/11] fix FragmentSmack in stable branch (CVE-2018-5391) Greg KH
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