linux-kernel - Re: [PATCH] IPVS: replace sprintf to snprintf to avoid stack buffer overflow

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: <4BBCAE52.9080501@trash.net>
Date:	Wed, 07 Apr 2010 18:09:54 +0200
From:	Patrick McHardy <kaber@...sh.net>
To:	Simon Horman <horms@...ge.net.au>
CC:	wzt.wzt@...il.com, linux-kernel@...r.kernel.org,
	Wensong Zhang <wensong@...ux-vs.org>,
	Julian Anastasov <ja@....bg>, netdev@...r.kernel.org,
	lvs-devel@...r.kernel.org
Subject: Re: [PATCH] IPVS: replace sprintf to snprintf to avoid stack buffer
 overflow

Simon Horman wrote:
> On Tue, Apr 06, 2010 at 10:50:20AM +0800, wzt.wzt@...il.com wrote:
>> IPVS not check the length of pp->name, use sprintf will cause stack buffer overflow.
>> struct ip_vs_protocol{} declare name as char *, if register a protocol as:
>> struct ip_vs_protocol ip_vs_test = {
>>         .name =			"aaaaaaaa....128...aaa",
>> 	.debug_packet =         ip_vs_tcpudp_debug_packet,
>> };
>>
>> when called ip_vs_tcpudp_debug_packet(), sprintf(buf, "%s TRUNCATED", pp->name); 
>> will cause stack buffer overflow.
>>
>> Signed-off-by: Zhitong Wang <zhitong.wangzt@...baba-inc.com>
> 
> I think that the simple answer is, don't do that.

Indeed.

> But your patch seems entirely reasonable to me.
> 
> Acked-by: Simon Horman <horms@...ge.net.au>
> 
> Patrick, please consider merging this.

I think this fix is a bit silly, we can simply print the name in
the pr_debug() statement and avoid both the potential overflow
and truncation.

How does this look?

View attachment "x" of type "text/plain" (3386 bytes)