netdev - Re: [PATCH] ipv6: check if dereference of ipv6 header is safe

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <1358536346.11051.580.camel@edumazet-glaptop>
Date:	Fri, 18 Jan 2013 11:12:26 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Hannes Frederic Sowa <hannes@...essinduktion.org>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH] ipv6: check if dereference of ipv6 header is safe

On Fri, 2013-01-18 at 04:08 +0100, Hannes Frederic Sowa wrote:

> Please correct me if I am wrong:
> 
> The callstack as captured in ipip6_rcv:
>     ipip6_rcv+0xcd/0x680 [sit]
>     tunnel64_rcv+0x4a/0x174 [tunnel4]
>     ip_local_deliver+0x152/0x470
>     ? ip_local_deliver+0x75/0x470
>     ip_rcv+0x36d/0x650
> 
> ip_rcv does first check if the ipv4 header is complete (inclusive options) and
> passes control to ip_local_deliver which calls __skb_pull(skb,
> ip_hdrlen(skb)). So ->data is forwarded behind the ipv4 header. The next
> pskb_may_pull check would check if the necessary amount of data behind the
> ipv4 header is available hence I assume the check in tunnel64_rcv is enough:

Oh, yes, thats fine.



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html