netdev - Re: [PATCH] ipv6: sr: fix get_srh() to comply with IPv6 standard "RFC 8200"

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Date:   Mon, 28 Aug 2017 19:48:15 +0100
From:   David Lebrun <david.lebrun@...ouvain.be>
To:     Ahmed Abdelsalam <amsalam20@...il.com>, <davem@...emloft.net>
CC:     <yoshfuji@...ux-ipv6.org>, <netdev@...r.kernel.org>
Subject: Re: [PATCH] ipv6: sr: fix get_srh() to comply with IPv6 standard "RFC
 8200"

On 08/28/2017 07:20 PM, Ahmed Abdelsalam wrote:
> This patch fixes the get_srh(), so it gets the segment routing header
> regardless of its position in the chain of the extension headers in IPv6
> packet, and makes sure that the IPv6 routing extension header is of
> Type 4.

Ahmed,

You need to initialize srhoff to 0, otherwise ipv6_find_hdr() will crash
the kernel by dereferencing an uninitialized pointer.

Please test your patches before submitting them.

Furthermore, your pskb_may_pull() check should happen right after the
call to ipv6_find_hdr, with srhoff + sizeof(*srh) as argument. Once you
have checked the SRH type, you can then do another pskb_may_pull with
srhoff + len.

David

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