2019-11-01 14:30:22

by Colin King

Subject: [PATCH] staging: rtl8192u: fix potential infinite loop because loop counter being too small

From: Colin Ian King <[email protected]>

Currently the for-loop counter i is a u8 however it is being checked
against a maximum value priv->ieee80211->LinkDetectInfo.SlotNum which is a
u16. Hence there is a potential wrap-around of counter i back to zero if
priv->ieee80211->LinkDetectInfo.SlotNum is greater than 255. Fix this by
making i a u16.

Addresses-Coverity: ("Infinite loop")
Fixes: 8fc8598e61f6 ("Staging: Added Realtek rtl8192u driver to staging")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/staging/rtl8192u/r8192U_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8192u/r8192U_core.c b/drivers/staging/rtl8192u/r8192U_core.c
index 48f1591ed5b4..fd91b7c5ca81 100644
--- a/drivers/staging/rtl8192u/r8192U_core.c
+++ b/drivers/staging/rtl8192u/r8192U_core.c
@@ -3210,7 +3210,7 @@ static void rtl819x_update_rxcounts(struct r8192_priv *priv, u32 *TotalRxBcnNum,
u32 *TotalRxDataNum)
{
u16 SlotIndex;
- u8 i;
+ u16 i;

*TotalRxBcnNum = 0;
*TotalRxDataNum = 0;
--
2.20.1

2019-11-01 14:54:17

by Dan Carpenter

Subject: Re: [PATCH] staging: rtl8192u: fix potential infinite loop because loop counter being too small

On Fri, Nov 01, 2019 at 02:26:04PM +0000, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> Currently the for-loop counter i is a u8 however it is being checked
> against a maximum value priv->ieee80211->LinkDetectInfo.SlotNum which is a
> u16. Hence there is a potential wrap-around of counter i back to zero if
> priv->ieee80211->LinkDetectInfo.SlotNum is greater than 255. Fix this by
> making i a u16.
>
> Addresses-Coverity: ("Infinite loop")
> Fixes: 8fc8598e61f6 ("Staging: Added Realtek rtl8192u driver to staging")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/staging/rtl8192u/r8192U_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/rtl8192u/r8192U_core.c b/drivers/staging/rtl8192u/r8192U_core.c
> index 48f1591ed5b4..fd91b7c5ca81 100644
> --- a/drivers/staging/rtl8192u/r8192U_core.c
> +++ b/drivers/staging/rtl8192u/r8192U_core.c
> @@ -3210,7 +3210,7 @@ static void rtl819x_update_rxcounts(struct r8192_priv *priv, u32 *TotalRxBcnNum,
> u32 *TotalRxDataNum)
> {
> u16 SlotIndex;
> - u8 i;
> + u16 i;

The iterator "i" should just be an int unless we know that it needs to
be an unsigned long long.

regards,
dan carpenter

2019-11-02 12:53:58

by walter harms

Subject: Re: [PATCH] staging: rtl8192u: fix potential infinite loop because loop counter being too small

Am 01.11.2019 15:51, schrieb Dan Carpenter:
> On Fri, Nov 01, 2019 at 02:26:04PM +0000, Colin King wrote:
>> From: Colin Ian King <[email protected]>
>>
>> Currently the for-loop counter i is a u8 however it is being checked
>> against a maximum value priv->ieee80211->LinkDetectInfo.SlotNum which is a
>> u16. Hence there is a potential wrap-around of counter i back to zero if
>> priv->ieee80211->LinkDetectInfo.SlotNum is greater than 255. Fix this by
>> making i a u16.
>>
>> Addresses-Coverity: ("Infinite loop")
>> Fixes: 8fc8598e61f6 ("Staging: Added Realtek rtl8192u driver to staging")
>> Signed-off-by: Colin Ian King <[email protected]>
>> ---
>> drivers/staging/rtl8192u/r8192U_core.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/staging/rtl8192u/r8192U_core.c b/drivers/staging/rtl8192u/r8192U_core.c
>> index 48f1591ed5b4..fd91b7c5ca81 100644
>> --- a/drivers/staging/rtl8192u/r8192U_core.c
>> +++ b/drivers/staging/rtl8192u/r8192U_core.c
>> @@ -3210,7 +3210,7 @@ static void rtl819x_update_rxcounts(struct r8192_priv *priv, u32 *TotalRxBcnNum,
>> u32 *TotalRxDataNum)
>> {
>> u16 SlotIndex;
>> - u8 i;
>> + u16 i;
>
> The iterator "i" should just be an int unless we know that it needs to
> be an unsigned long long.
>

+1

i think we can spare the 2byte. ppl expect int and will get confused (as shown here).

re,
wh