netdev - [patch] hostap: fixup strlen() math

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Message-ID: <20100710221042.GA14911@bicker>
Date:	Sun, 11 Jul 2010 00:10:42 +0200
From:	Dan Carpenter <error27@...il.com>
To:	Jouni Malinen <j@...fi>
Cc:	"John W. Linville" <linville@...driver.com>,
	Martin Decky <martin@...ky.cz>, linux-wireless@...r.kernel.org,
	netdev@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [patch] hostap: fixup strlen() math

In hostap_add_interface() we do:
	sprintf(dev->name, "%s%s", prefix, name);

dev->name has IFNAMSIZ (16) characters.
prefix is local->dev->name.
name is "wds%d"

strlen() returns the number of characters in the string not counting the
NULL so if we have a string with 11 characters we get "12345678901wds%d"
which is 16 characters and a NULL so we're past the end of the array.

Signed-off-by: Dan Carpenter <error27@...il.com>

diff --git a/drivers/net/wireless/hostap/hostap_main.c b/drivers/net/wireless/hostap/hostap_main.c
index eb57d1e..f1bc258 100644
--- a/drivers/net/wireless/hostap/hostap_main.c
+++ b/drivers/net/wireless/hostap/hostap_main.c
@@ -186,7 +186,7 @@ int prism2_wds_add(local_info_t *local, u8 *remote_addr,
 		return -ENOBUFS;
 
 	/* verify that there is room for wds# postfix in the interface name */
-	if (strlen(local->dev->name) > IFNAMSIZ - 5) {
+	if (strlen(local->dev->name) >= IFNAMSIZ - 5) {
 		printk(KERN_DEBUG "'%s' too long base device name\n",
 		       local->dev->name);
 		return -EINVAL;
--
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