libertas: Read buffer overflow

Check whether index is within bounds before testing the element.

(also includes "Libertas: Association request to the driver failed"

The size of the tmp buffer was too small, causing a regression

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

In get_common_rates() the memset/memcpy can be moved upwards. -- JWL)

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Tested-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 15 insertions, 16 deletions

diff --git a/drivers/net/wireless/libertas/assoc.c b/drivers/net/wireless/libertas/assoc.c
index 81f86ef26990..a9440a96b2e7 100644
--- a/drivers/net/wireless/libertas/assoc.c
+++ b/drivers/net/wireless/libertas/assoc.c
@@ -44,12 +44,11 @@ static int get_common_rates(struct lbs_private *priv,
 {
         u8 *card_rates = lbs_bg_rates;
         size_t num_card_rates = sizeof(lbs_bg_rates);
-        int ret = 0, i, j;
+        int i, j;
         u8 *tmp;
         size_t tmp_size = 0;
 
-        tmp = kzalloc((ARRAY_SIZE(lbs_bg_rates) - 1) * (*rates_size - 1),
-                        GFP_KERNEL);
+        tmp = kzalloc(MAX_RATES * ARRAY_SIZE(lbs_bg_rates), GFP_KERNEL);
         if (!tmp)
                 return -1;
 
@@ -66,24 +65,24 @@ static int get_common_rates(struct lbs_private *priv,
         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);
         kfree(tmp);
-        return ret;
+        return 0;
 }
 
 
@@ -325,8 +324,8 @@ 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;
+        memcpy(&rates->rates, &bss->rates, tmplen);
         if (get_common_rates(priv, rates->rates, &tmplen)) {
                 ret = -1;
                 goto done;