Message-ID: <4644DD9A.2080001@goop.org>
Date: Fri, 11 May 2007 14:18:18 -0700
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: =?ISO-8859-15?Q?Ren=E9_Scharfe?= <rene.scharfe@lsrfire.ath.cx>
CC: Andi Kleen <ak@suse.de>, Andrew Morton <akpm@linux-foundation.org>,
       lkml <linux-kernel@vger.kernel.org>, Chris Wright <chrisw@sous-sol.org>,
       Randy Dunlap <randy.dunlap@oracle.com>,
       YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>,
       Akinobu Mita <akinobu.mita@gmail.com>,
       Arnaldo Carvalho de Melo <acme@mandriva.com>,
       Al Viro <viro@ftp.linux.org.uk>, Panagiotis Issaris <takis@issaris.org>
Subject: Re: [patch 3/7] add kstrndup
References: <20070510235708.155502000@goop.org> <20070511000027.091968000@goop.org> <4644D779.30908@lsrfire.ath.cx>
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Ren? Scharfe wrote:
>> +	len = strlen(s);
>> +	if (len > max)
>> +		len = max;
>>     
>
> You can avoid to run beyond max and save two lines by using strnlen:
>
> 	len = strnlen(s, max);
>   

OK.  Didn't know about strnlen.

Subject: Use strnlen in kstrndup

strnlen prevents over-reading the input.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Ren? Scharfe <rene.scharfe@lsrfire.ath.cx>

---
 mm/util.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

===================================================================
--- a/mm/util.c
+++ b/mm/util.c
@@ -53,9 +53,7 @@ char *kstrndup(const char *s, size_t max
 	if (!s)
 		return NULL;
 
-	len = strlen(s);
-	if (len > max)
-		len = max;
+	len = strnlen(s, max);
 	buf = kmalloc_track_caller(len+1, gfp);
  	if (buf) {
 		memcpy(buf, s, len);


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