linux-kernel - Re: gcc fixed size char array initialization bug

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: <20070803034001.GA3476@localhost.localdomain>
Date:	Fri, 3 Aug 2007 11:40:01 +0800
From:	WANG Cong <xiyou.wangcong@...il.com>
To:	Satyam Sharma <satyam@...radead.org>
Cc:	Jan Engelhardt <jengelh@...putergmbh.de>,
	Guennadi Liakhovetski <g.liakhovetski@....de>,
	linux-kernel@...r.kernel.org
Subject: Re: gcc fixed size char array initialization bug - known?

On Fri, Aug 03, 2007 at 08:47:56AM +0530, Satyam Sharma wrote:
>
>
>On Thu, 2 Aug 2007, Jan Engelhardt wrote:
>
>> On Aug 2 2007 21:55, Guennadi Liakhovetski wrote:
>> > [...]
>> >
>> >	struct {
>> >		char c[4];
>> >		int i;
>> >	} t;
>> >	t.i = 0x12345678;
>> >	strcpy(t.c, c);
>> >
>> >and t.i is silently corrupted. Just wanted to ask if this is known, 
>> >really...
>> 
>> What does this have to do with the kernel? The string "0123" is
>> generally _five_ characters long, so c[4] is not enough.
>> Or use strncpy.
>
><nitpicking>
>
>While we're talking of null-termination of strings, then I bet you
>generally want to be using strlcpy(), really. Often strncpy() isn't
>what you want. Of course, if that buffer isn't a string at all, then
>you should be using memfoo() functions and not strbar() ones in the
>first place ...

Afaik, strlcpy() and strlcat() are NOT standard C library functions.
But, I know, they are available in Linux kernel. ;) And yes, they
are better than strn{cpy,cat}().

Regards.

-- 
_   /|
\'o.O'
=(___)=
   U 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/