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@xxxxxxxxx>
---
> | 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");
--
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