From: David Ahern <dsahern@gmail.com>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
Balazs Nemeth <bnemeth@redhat.com>
Cc: Network Development <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
David Miller <davem@davemloft.net>,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v2 2/2] net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0
Date: Mon, 8 Mar 2021 09:17:12 -0700 [thread overview]
Message-ID: <718e4f13-31a8-037c-9725-08ae3cd93ccd@gmail.com> (raw)
In-Reply-To: <CA+FuTSdWSCzkB7sDn+_0Oxy8JqmqL=nsQXP_3bnb4Xdd=0A=KQ@mail.gmail.com>
On 3/8/21 9:07 AM, Willem de Bruijn wrote:
>> diff --git a/net/mpls/mpls_gso.c b/net/mpls/mpls_gso.c
>> index b1690149b6fa..cc1b6457fc93 100644
>> --- a/net/mpls/mpls_gso.c
>> +++ b/net/mpls/mpls_gso.c
>> @@ -27,7 +27,7 @@ static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
>>
>> skb_reset_network_header(skb);
>> mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
>> - if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
>> + if (unlikely(!mpls_hlen || !pskb_may_pull(skb, mpls_hlen)))
>> goto out;
>
> Good cathc. Besides length zero, this can be more strict: a label is
> 4B, so mpls_hlen needs to be >= 4B.
>
> Perhaps even aligned to 4B, too, but not if there may be other encap on top.
>
> Unfortunately there is no struct or type definition that we can use a
> sizeof instead of open coding the raw constant.
>
MPLS_HLEN can be used here.
next prev parent reply other threads:[~2021-03-08 16:18 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-08 10:31 [PATCH v2 0/2] net: prevent infinite loop caused by incorrect proto from virtio_net_hdr_set_proto Balazs Nemeth
2021-03-08 10:31 ` [PATCH v2 1/2] net: check if protocol extracted by virtio_net_hdr_set_proto is correct Balazs Nemeth
2021-03-08 16:01 ` Willem de Bruijn
2021-03-09 11:26 ` Michael S. Tsirkin
2021-03-09 14:02 ` Willem de Bruijn
2021-03-08 10:31 ` [PATCH v2 2/2] net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0 Balazs Nemeth
2021-03-08 16:07 ` Willem de Bruijn
2021-03-08 16:17 ` David Ahern [this message]
2021-03-08 16:26 ` Balazs Nemeth
2021-03-08 16:42 ` David Ahern
2021-03-08 18:11 ` Willem de Bruijn
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