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From: Roel Kluin <roel.kluin@gmail.com>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Michael Buesch <mb@bu3sch.de>, Daniel Mack <daniel@caiaq.de>,
	"John W. Linville" <linville@tuxdriver.com>,
	libertas-dev@lists.infradead.org, linux-wireless@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: Libertas: Association request to the driver failed
Date: Mon, 10 Aug 2009 12:37:00 +0200	[thread overview]
Message-ID: <4A7FF84C.7070708@gmail.com> (raw)
In-Reply-To: <20090809191359.GG4805@lenovo>

Several arrays were read before checking whether the index was within
bounds. ARRAY_SIZE() should be used to determine the size of arrays.

rates->rates has an arraysize of 1, so calling get_common_rates()
with a rates_size of MAX_RATES (14) was causing reads out of bounds.

tmp_size can increment at most to MAX_RATES * ARRAY_SIZE(lbs_bg_rates),
so that should be the number of elements of tmp[].

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---

> | Is it a good idea to use dynamic stack arrays in the kernel?
> | What about kmalloc for dynamic allocations?
> | 
> | -- 
> | Greetings, Michael.
> 
> I saw one pattern in trace code (not sure if it's
> still there) but personally don't like dynamic
> stack arrays (though at moment the max value
> being passed into routine is known maybe just
> use MAX_RATES instead of (*rates_size)?). Hmm?

Good point.

> 	-- Cyrill

Thanks,

I think there was another problem in lbs_associate(),
the memcpy already affected rates->rates.

Also in get_common_rates() I think we can safely move the
memset/memcpy, originally after label done, upwards.

The patch below, if correct, is to be applied after the revert

Roel

diff --git a/drivers/net/wireless/libertas/assoc.c b/drivers/net/wireless/libertas/assoc.c
index b9b3741..ba0164a 100644
--- a/drivers/net/wireless/libertas/assoc.c
+++ b/drivers/net/wireless/libertas/assoc.c
@@ -1,6 +1,7 @@
 /* Copyright (C) 2006, Red Hat, Inc. */
 
 #include <linux/types.h>
+#include <linux/kernel.h>
 #include <linux/etherdevice.h>
 #include <linux/ieee80211.h>
 #include <linux/if_arp.h>
@@ -43,41 +44,41 @@ static int get_common_rates(struct lbs_private *priv,
 	u16 *rates_size)
 {
 	u8 *card_rates = lbs_bg_rates;
-	size_t num_card_rates = sizeof(lbs_bg_rates);
-	int ret = 0, i, j;
-	u8 tmp[30];
+	int i, j;
+	u8 tmp[MAX_RATES * ARRAY_SIZE(lbs_bg_rates)];
 	size_t tmp_size = 0;
 
 	/* For each rate in card_rates that exists in rate1, copy to tmp */
-	for (i = 0; card_rates[i] && (i < num_card_rates); i++) {
-		for (j = 0; rates[j] && (j < *rates_size); j++) {
+	for (i = 0; i < ARRAY_SIZE(lbs_bg_rates) && card_rates[i]; i++) {
+		for (j = 0; j < *rates_size && rates[j]; j++) {
 			if (rates[j] == card_rates[i])
 				tmp[tmp_size++] = card_rates[i];
 		}
 	}
 
 	lbs_deb_hex(LBS_DEB_JOIN, "AP rates    ", rates, *rates_size);
-	lbs_deb_hex(LBS_DEB_JOIN, "card rates  ", card_rates, num_card_rates);
+	lbs_deb_hex(LBS_DEB_JOIN, "card rates  ", card_rates,
+			ARRAY_SIZE(lbs_bg_rates));
 	lbs_deb_hex(LBS_DEB_JOIN, "common rates", tmp, tmp_size);
 	lbs_deb_join("TX data rate 0x%02x\n", priv->cur_rate);
 
+	memset(rates, 0, *rates_size);
+	*rates_size = min_t(u16, tmp_size, *rates_size);
+	memcpy(rates, tmp, *rates_size);
+
 	if (!priv->enablehwauto) {
 		for (i = 0; i < tmp_size; i++) {
 			if (tmp[i] == priv->cur_rate)
-				goto done;
+				break;
+		}
+		if (i == tmp_size) {
+			lbs_pr_alert("Previously set fixed data rate %#x isn't "
+					"compatible with the network.\n",
+					priv->cur_rate);
+			return -1;
 		}
-		lbs_pr_alert("Previously set fixed data rate %#x isn't "
-		       "compatible with the network.\n", priv->cur_rate);
-		ret = -1;
-		goto done;
 	}
-	ret = 0;
-
-done:
-	memset(rates, 0, *rates_size);
-	*rates_size = min_t(int, tmp_size, *rates_size);
-	memcpy(rates, tmp, *rates_size);
-	return ret;
+	return 0;
 }
 
 
@@ -321,8 +322,8 @@ static int lbs_associate(struct lbs_private *priv,
 
 	rates = (struct mrvl_ie_rates_param_set *) pos;
 	rates->header.type = cpu_to_le16(TLV_TYPE_RATES);
-	memcpy(&rates->rates, &bss->rates, MAX_RATES);
-	tmplen = MAX_RATES;
+	tmplen = min_t(u16, ARRAY_SIZE(rates->rates), MAX_RATES);
+	memcpy(&rates->rates, &bss->rates, tmplen);
 	if (get_common_rates(priv, rates->rates, &tmplen)) {
 		ret = -1;
 		goto done;
@@ -598,7 +599,7 @@ static int lbs_adhoc_join(struct lbs_private *priv,
 
 	/* Copy Data rates from the rates recorded in scan response */
 	memset(cmd.bss.rates, 0, sizeof(cmd.bss.rates));
-	ratesize = min_t(u16, sizeof(cmd.bss.rates), MAX_RATES);
+	ratesize = min_t(u16, ARRAY_SIZE(cmd.bss.rates), MAX_RATES);
 	memcpy(cmd.bss.rates, bss->rates, ratesize);
 	if (get_common_rates(priv, cmd.bss.rates, &ratesize)) {
 		lbs_deb_join("ADHOC_JOIN: get_common_rates returned error.\n");

  reply	other threads:[~2009-08-10 10:33 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-07 19:11 Daniel Mack
2009-08-07 19:36 ` John W. Linville
2009-08-07 20:50   ` Marek Vasut
2009-08-08 12:35   ` Daniel Mack
2009-08-08 14:24     ` Roel Kluin
2009-08-09  9:23       ` Roel Kluin
2009-08-09 10:24         ` Daniel Mack
2009-08-09 11:11           ` Roel Kluin
2009-08-09 11:10             ` Michael Buesch
2009-08-09 19:13               ` Cyrill Gorcunov
2009-08-10 10:37                 ` Roel Kluin [this message]
2009-08-10 14:04                   ` Cyrill Gorcunov
2009-08-10 17:47                   ` Daniel Mack
2009-08-12  8:17                     ` Jonathan Cameron
2009-08-12  8:47                   ` Jonathan Cameron
2009-08-12 16:16                     ` Dan Williams
2009-08-10 17:59             ` John W. Linville
2009-08-11  7:02               ` Roel Kluin
2009-08-11 18:24                 ` John W. Linville
2009-08-12 16:15                   ` Dan Williams
2009-08-12 17:34                     ` Dan Williams
2009-08-07 21:21 ` Dan Williams

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