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From: Greg Kroah-Hartman <gregkh@linuxfoundation•org>
To: linux-kernel@vger•kernel.org, netdev@vger•kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
	stable@vger•kernel.org, Peter Oskolkov <posk@google•com>,
	Eric Dumazet <edumazet@google•com>,
	Florian Westphal <fw@strlen•de>,
	"David S. Miller" <davem@davemloft•net>
Subject: [PATCH 4.9 64/71] ipv6: defrag: drop non-last frags smaller than min mtu
Date: Tue, 16 Oct 2018 19:10:01 +0200	[thread overview]
Message-ID: <20181016170542.593416686@linuxfoundation.org> (raw)
In-Reply-To: <20181016170539.315587743@linuxfoundation.org>

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) {

  parent reply	other threads:[~2018-10-16 17:10 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20181016170539.315587743@linuxfoundation.org>
2018-10-16 17:09 ` [PATCH 4.9 43/71] inet: frags: change inet_frags_init_net() return value Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 44/71] inet: frags: add a pointer to struct netns_frags Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 45/71] inet: frags: refactor ipfrag_init() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 46/71] inet: frags: refactor ipv6_frag_init() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 47/71] inet: frags: refactor lowpan_net_frag_init() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 48/71] ipv6: export ip6 fragments sysctl to unprivileged users Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 49/71] rhashtable: add schedule points Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 50/71] inet: frags: use rhashtables for reassembly units Greg Kroah-Hartman
2018-10-26 13:39   ` Stefan Schmidt
2018-11-29 12:54     ` Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 51/71] inet: frags: remove some helpers Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 52/71] inet: frags: get rif of inet_frag_evicting() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 53/71] inet: frags: remove inet_frag_maybe_warn_overflow() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 54/71] inet: frags: break the 2GB limit for frags storage Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 55/71] inet: frags: do not clone skb in ip_expire() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 56/71] ipv6: frags: rewrite ip6_expire_frag_queue() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 57/71] rhashtable: reorganize struct rhashtable layout Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 58/71] inet: frags: reorganize struct netns_frags Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 59/71] inet: frags: get rid of ipfrag_skb_cb/FRAG_CB Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 60/71] inet: frags: fix ip6frag_low_thresh boundary Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 61/71] ip: discard IPv4 datagrams with overlapping segments Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 62/71] net: speed up skb_rbtree_purge() Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 63/71] net: modify skb_rbtree_purge to return the truesize of all purged skbs Greg Kroah-Hartman
2018-10-16 17:10 ` Greg Kroah-Hartman [this message]
2018-10-16 17:10 ` [PATCH 4.9 65/71] net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 66/71] net: add rb_to_skb() and other rb tree helpers Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 67/71] ip: use rb trees for IP frag queue Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 68/71] ip: add helpers to process in-order fragments faster Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 69/71] ip: process in-order fragments efficiently Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 70/71] ip: frags: fix crash in ip_do_fragment() Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 71/71] ipv4: frags: precedence bug in ip_expire() Greg Kroah-Hartman

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