linux-kernel - Re: [PATCH] isdnloop: NUL-terminate strings from userspace

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Message-Id: <20140401.161838.1562296825577866979.davem@davemloft.net>
Date:	Tue, 01 Apr 2014 16:18:38 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	dan.carpenter@...cle.com
Cc:	vegard.nossum@...cle.com, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] isdnloop: NUL-terminate strings from userspace

From: Dan Carpenter <dan.carpenter@...cle.com>
Date: Tue, 1 Apr 2014 15:35:34 +0300

> I don't understand what you think the point of strlcpy() is, if it's not
> to deal with source strings which aren't NUL terminated.

If strlcpy() is meant to handle non-NULL terminated strings, then it's
kernel doc needs to be adjusted.

/**
 * strlcpy - Copy a %NUL terminated string into a sized buffer
 * @dest: Where to copy the string to
 * @src: Where to copy the string from
 * @size: size of destination buffer
 *
 * Compatible with *BSD: the result is always a valid
 * NUL-terminated string that fits in the buffer (unless,
 * of course, the buffer size is zero). It does not pad
 * out the result like strncpy() does.
 */

That says to me that 'src' is expected to be NULL terminated.

Furthermore, I like YOSHIFUJI Hideaki's idea that we should
actually validate the string and return -EINVAL if it is not
given to us NULL terminated.
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