zd1211rw: fix potential array underflow

The first chunk fixes a debugging assert to print a warning about array underflows.
The second chunk corrects a potential array underflow.  I also removed an assert
in the second chunk because it can no longer happen.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Benoit Papillault <benoit.papillault@free.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 6 deletions

diff --git a/drivers/net/wireless/zd1211rw/zd_mac.c b/drivers/net/wireless/zd1211rw/zd_mac.c
index 2d555cc30508..e24099613d91 100644
--- a/drivers/net/wireless/zd1211rw/zd_mac.c
+++ b/drivers/net/wireless/zd1211rw/zd_mac.c
@@ -350,7 +350,7 @@ static void zd_mac_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb,
         first_idx = info->status.rates[0].idx;
         ZD_ASSERT(0<=first_idx && first_idx<ARRAY_SIZE(zd_retry_rates));
         retries = &zd_retry_rates[first_idx];
-        ZD_ASSERT(0<=retry && retry<=retries->count);
+        ZD_ASSERT(1 <= retry && retry <= retries->count);
 
         info->status.rates[0].idx = retries->rate[0];
         info->status.rates[0].count = 1; // (retry > 1 ? 2 : 1);
@@ -360,7 +360,7 @@ static void zd_mac_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb,
                 info->status.rates[i].count = 1; // ((i==retry-1) && success ? 1:2);
         }
         for (; i<IEEE80211_TX_MAX_RATES && i<retry; i++) {
-                info->status.rates[i].idx = retries->rate[retry-1];
+                info->status.rates[i].idx = retries->rate[retry - 1];
                 info->status.rates[i].count = 1; // (success ? 1:2);
         }
         if (i<IEEE80211_TX_MAX_RATES)
@@ -424,12 +424,10 @@ void zd_mac_tx_failed(struct urb *urb)
                 first_idx = info->status.rates[0].idx;
                 ZD_ASSERT(0<=first_idx && first_idx<ARRAY_SIZE(zd_retry_rates));
                 retries = &zd_retry_rates[first_idx];
-                if (retry < 0 || retry > retries->count) {
+                if (retry <= 0 || retry > retries->count)
                         continue;
-                }
 
-                ZD_ASSERT(0<=retry && retry<=retries->count);
-                final_idx = retries->rate[retry-1];
+                final_idx = retries->rate[retry - 1];
                 final_rate = zd_rates[final_idx].hw_value;
 
                 if (final_rate != tx_status->rate) {