Re: [patch 3/7] add kstrndup

[Jeremy Fitzhardinge <jeremy@goop.org>]

René 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: René 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);