From: Greg KH <gregkh@linux-foundation.org>
To: Mao Wenan <maowenan@huawei.com>
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com,
davem@davemloft.net, stable@vger.kernel.org, edumazet@google.com
Subject: Re: [PATCH stable 4.4 06/11] ipv6: defrag: drop non-last frags smaller than min mtu
Date: Thu, 24 Jan 2019 19:31:03 +0100 [thread overview]
Message-ID: <20190124183103.GA18657@kroah.com> (raw)
In-Reply-To: <1548209986-83527-7-git-send-email-maowenan@huawei.com>
On Wed, Jan 23, 2019 at 10:19:41AM +0800, Mao Wenan wrote:
> 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..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;
This backport is incorrect, you should be returning a pointer, right?
How did you test this? This should have blown up under test :(
I'm going to drop this whole series. Please fix it up and test it
properly and then resend.
thanks,
greg k-h
next prev parent reply other threads:[~2019-01-24 18:31 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-23 2:19 [PATCH stable 4.4 00/11] fix FragmentSmack in stable branch (CVE-2018-5391) Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 01/11] net: speed up skb_rbtree_purge() Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 02/11] ip: discard IPv4 datagrams with overlapping segments Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 03/11] net: modify skb_rbtree_purge to return the truesize of all purged skbs Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 04/11] inet: frags: get rif of inet_frag_evicting() Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 05/11] ip: use rb trees for IP frag queue Mao Wenan
2019-01-24 17:58 ` Greg KH
2019-01-25 1:50 ` maowenan
2019-01-25 7:07 ` Greg KH
2019-01-25 8:12 ` maowenan
2019-01-23 2:19 ` [PATCH stable 4.4 06/11] ipv6: defrag: drop non-last frags smaller than min mtu Mao Wenan
2019-01-24 18:31 ` Greg KH [this message]
2019-01-25 2:24 ` maowenan
2019-01-23 2:19 ` [PATCH stable 4.4 07/11] ip: add helpers to process in-order fragments faster Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 08/11] ip: process in-order fragments efficiently Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 09/11] net: ipv4: do not handle duplicate fragments as overlapping Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 10/11] ip: frags: fix crash in ip_do_fragment() Mao Wenan
2019-01-23 2:19 ` [PATCH stable 4.4 11/11] ipv4: frags: precedence bug in ip_expire() Mao Wenan
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