Re: [patch] Staging: rtl8192u: fix some memory corruption

[Larry Finger <Larry.Finger@lwfinger.net>]

On 04/17/2012 01:45 AM, Dan Carpenter wrote:
> When we recieved a command we incremented a stat counter depending on
> the type of message.  The problem is there were 8 types of commands but
> there were only 4 counters allocated so it corrupted memory past the
> end of the rxcmdpkt[] array.
>
> The fix is just to remove the counters because they aren't used.
>
> Signed-off-by: Dan Carpenter<dan.carpenter@oracle.com>
> ---
> I don't think the layout of the stats struct matters, but I don't have
> the hardware to test this.

I don't have the hardware either, but in all of the Realtek-based drivers the 
only structs that require strict layout are the RX and TX descriptors. This 
change should be benign. I doubt that the code relies on the corruption of the 
overrun.

You have a typo in the commit message. After you fix that, then

ACKed-by: Larry Finger <Larry.Finger@lwfinger.net>

>
> diff --git a/drivers/staging/rtl8192u/r8192U.h b/drivers/staging/rtl8192u/r8192U.h
> index 9b81f26..43d459d 100644
> --- a/drivers/staging/rtl8192u/r8192U.h
> +++ b/drivers/staging/rtl8192u/r8192U.h
> @@ -610,7 +610,6 @@ typedef struct Stats
>   //	unsigned long rxnopointer;
>   	unsigned long rxok;
>   	unsigned long rxframgment;
> -	unsigned long rxcmdpkt[4];		//08/05/08 amy rx cmd element txfeedback/bcn report/cfg set/query
>   	unsigned long rxurberr;
>   	unsigned long rxstaterr;
>   	unsigned long received_rate_histogram[4][32];	//0: Total, 1:OK, 2:CRC, 3:ICV, 2007 07 03 cosa
> diff --git a/drivers/staging/rtl8192u/r819xU_cmdpkt.c b/drivers/staging/rtl8192u/r819xU_cmdpkt.c
> index 0cb28c7..9348f42 100644
> --- a/drivers/staging/rtl8192u/r819xU_cmdpkt.c
> +++ b/drivers/staging/rtl8192u/r819xU_cmdpkt.c
> @@ -697,7 +697,6 @@ cmpk_message_handle_rx(
>   	struct ieee80211_rx_stats *pstats)
>   {
>   //	u32			debug_level = DBG_LOUD;
> -	struct r8192_priv *priv = ieee80211_priv(dev);
>   	int			total_length;
>   	u8			cmd_length, exe_cnt = 0;
>   	u8			element_id;
> @@ -779,9 +778,6 @@ cmpk_message_handle_rx(
>   		// 2007/01/22 MH Add to display tx statistic.
>   		//cmpk_DisplayTxStatistic(pAdapter);
>
> -		/* 2007/03/09 MH Collect sidderent cmd element pkt num. */
> -		priv->stats.rxcmdpkt[element_id]++;
> -
>   		total_length -= cmd_length;
>   		pcmd_buff    += cmd_length;
>   	}	/* while (total_length>  0) */
>