From: Ruben Kerkhof <ruben@rubenkerkhof.com>
Date: Fri, 4 Dec 2015 20:03:44 +0000 (+0100)
Subject: madwifi: make code a little bit clearer
X-Git-Tag: collectd-5.5.1~25^2~9
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=51f407eeaf373508098a06b9e352b7ed794d6335;p=collectd.git

madwifi: make code a little bit clearer

buf2 is initialized to zero, readlink
will write at most sizeof(buf2) -1 bytes,
so the trailing null should not be overwritten.

Coverity doesn't see that, rewrite the code
differently so it does.

CID #38027

Signed-off-by: Florian Forster <octo@collectd.org>
---

diff --git a/src/madwifi.c b/src/madwifi.c
index 13301fff..7987378e 100644
--- a/src/madwifi.c
+++ b/src/madwifi.c
@@ -821,15 +821,16 @@ check_devname (const char *dev)
 
 	if (dev[0] == '.')
 		return 0;
-	
+
 	ssnprintf (buf, sizeof (buf), "/sys/class/net/%s/device/driver", dev);
-	buf[sizeof (buf) - 1] = 0;
+	buf[sizeof (buf) - 1] = '\0';
 
-	memset (buf2, 0, sizeof (buf2));
 	i = readlink (buf, buf2, sizeof (buf2) - 1);
 	if (i < 0)
 		return 0;
 
+	buf2[i] = '\0';
+
 	if (strstr (buf2, "/drivers/ath_") == NULL)
 		return 0;
 	return 1;