netdev - Re: [PATCH 3/3] net: tipc: fix information leak to userland

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

Message-ID: <4CDA88FE.8040801@bfs.de>
Date:	Wed, 10 Nov 2010 12:58:54 +0100
From:	walter harms <wharms@....de>
To:	Vasiliy Kulikov <segooon@...il.com>
CC:	David Miller <davem@...emloft.net>,
	kernel-janitors@...r.kernel.org, jon.maloy@...csson.com,
	allan.stephens@...driver.com,
	tipc-discussion@...ts.sourceforge.net, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] net: tipc: fix information leak to userland



Am 09.11.2010 21:33, schrieb Vasiliy Kulikov:
> On Tue, Nov 09, 2010 at 09:26 -0800, David Miller wrote:
>> From: Vasiliy Kulikov <segooon@...il.com>
>> Date: Sun, 31 Oct 2010 20:10:32 +0300
>>
>>> Structure sockaddr_tipc is copied to userland with padding bytes after
>>> "id" field in union field "name" unitialized.  It leads to leaking of
>>> contents of kernel stack memory.  We have to initialize them to zero.
>>>
>>> Signed-off-by: Vasiliy Kulikov <segooon@...il.com>
>>
>> Applied.
>>
>> Patches #1 and #2 were given feedback which I need you to integrate
>> and submit new patches based upon, thanks.
> 
> About #2:
> 
> I still think that this:
> 
>     if (dev)
>         strncpy(uaddr->sa_data, dev->name, 14);
>     else
>         memset(uaddr->sa_data, 0, 14);
> 
> is better than this:
> 
>     memset(uaddr->sa_data, 0, 14);
>     dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
>     if (dev)
>         strlcpy(uaddr->sa_data, dev->name, 15);
> 
> Doesn't it?  Explicitly filling with zero on the same "if" level is
> slightly easier to read and understand.
> 

no problem with me, since i came up with the idea a simple explanation:
IMHO the pattern clear/if/copy is more robust

NTL the core problem was that sizeof sa_data is 14 while dev->name is IFNAMESZ=15.


re,
 wh
--
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