[patch -next] pch_can: off by one bugs

[patch -next] pch_can: off by one bugs

[Dan Carpenter]

priv->tx_enable[] has PCH_TX_OBJ_END elements so this code is
reading and writing one past the end of the array.

Signed-off-by: Dan Carpenter <error27@gmail.com>

diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
index 8d45fdd..b2c1292 100644
--- a/drivers/net/can/pch_can.c
+++ b/drivers/net/can/pch_can.c
@@ -1077,7 +1077,7 @@ static int pch_can_suspend(struct pci_dev *pdev, pm_message_t state)
 	pch_can_set_int_enables(priv, PCH_CAN_DISABLE);
 
 	/* Save Tx buffer enable state */
-	for (i = PCH_TX_OBJ_START; i <= PCH_TX_OBJ_END; i++)
+	for (i = PCH_TX_OBJ_START; i < PCH_TX_OBJ_END; i++)
 		priv->tx_enable[i] = pch_can_get_rxtx_ir(priv, i, PCH_TX_IFREG);
 
 	/* Disable all Transmit buffers */
@@ -1138,7 +1138,7 @@ static int pch_can_resume(struct pci_dev *pdev)
 	pch_can_set_optmode(priv);
 
 	/* Enabling the transmit buffer. */
-	for (i = PCH_TX_OBJ_START; i <= PCH_TX_OBJ_END; i++)
+	for (i = PCH_TX_OBJ_START; i < PCH_TX_OBJ_END; i++)
 		pch_can_set_rxtx(priv, i, priv->tx_enable[i], PCH_TX_IFREG);
 
 	/* Configuring the receive buffer and enabling them. */

Re: [patch -next] pch_can: off by one bugs

[Wolfgang Grandegger]

Hello,

On 12/20/2010 10:26 AM, Dan Carpenter wrote:
> priv->tx_enable[] has PCH_TX_OBJ_END elements so this code is
> reading and writing one past the end of the array.
> 
> Signed-off-by: Dan Carpenter <error27-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
> index 8d45fdd..b2c1292 100644
> --- a/drivers/net/can/pch_can.c
> +++ b/drivers/net/can/pch_can.c
> @@ -1077,7 +1077,7 @@ static int pch_can_suspend(struct pci_dev *pdev, pm_message_t state)
>  	pch_can_set_int_enables(priv, PCH_CAN_DISABLE);
>  
>  	/* Save Tx buffer enable state */
> -	for (i = PCH_TX_OBJ_START; i <= PCH_TX_OBJ_END; i++)
> +	for (i = PCH_TX_OBJ_START; i < PCH_TX_OBJ_END; i++)
>  		priv->tx_enable[i] = pch_can_get_rxtx_ir(priv, i, PCH_TX_IFREG);
>  
>  	/* Disable all Transmit buffers */
> @@ -1138,7 +1138,7 @@ static int pch_can_resume(struct pci_dev *pdev)
>  	pch_can_set_optmode(priv);
>  
>  	/* Enabling the transmit buffer. */
> -	for (i = PCH_TX_OBJ_START; i <= PCH_TX_OBJ_END; i++)
> +	for (i = PCH_TX_OBJ_START; i < PCH_TX_OBJ_END; i++)
>  		pch_can_set_rxtx(priv, i, priv->tx_enable[i], PCH_TX_IFREG);
>  
>  	/* Configuring the receive buffer and enabling them. */
> 

This fix does not look correct too me. There are much more loop using
"i <= PCH_TX_OBJ_END" and the message numbering is from 1..32. Therefore
using "priv->tx_enable[i - 1]" seems more appropriate to me. Tomaya,
could you please check.

Thanks,

Wolfgang.

Re: [patch -next] pch_can: off by one bugs

[Tomoya MORINAGA]

On Wednesday, December 22, 2010 5:41 AM, Wolfgang Grandegger wrote:
> This fix does not look correct too me.
I agree with Wolfgang's comments.

> Dan
Thank you for your report.
I will post the patch by this week.

Thanks,
---
Tomoya MORINAGA
OKI SEMICONDUCTOR CO., LTD.

----- Original Message ----- 
From: "Wolfgang Grandegger" <wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>
To: "Dan Carpenter" <error27-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: <socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org>; <netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>; 
<kernel-janitors-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>; "Tomoya MORINAGA" 
<tomoya-linux-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
Sent: Wednesday, December 22, 2010 5:41 AM
Subject: Re: [patch -next] pch_can: off by one bugs


> Hello,
>
> On 12/20/2010 10:26 AM, Dan Carpenter wrote:
>> priv->tx_enable[] has PCH_TX_OBJ_END elements so this code is
>> reading and writing one past the end of the array.
>>
>> Signed-off-by: Dan Carpenter <error27-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>>
>> diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
>> index 8d45fdd..b2c1292 100644
>> --- a/drivers/net/can/pch_can.c
>> +++ b/drivers/net/can/pch_can.c
>> @@ -1077,7 +1077,7 @@ static int pch_can_suspend(struct pci_dev *pdev, 
>> pm_message_t state)
>>  pch_can_set_int_enables(priv, PCH_CAN_DISABLE);
>>
>>  /* Save Tx buffer enable state */
>> - for (i = PCH_TX_OBJ_START; i <= PCH_TX_OBJ_END; i++)
>> + for (i = PCH_TX_OBJ_START; i < PCH_TX_OBJ_END; i++)
>>  priv->tx_enable[i] = pch_can_get_rxtx_ir(priv, i, PCH_TX_IFREG);
>>
>>  /* Disable all Transmit buffers */
>> @@ -1138,7 +1138,7 @@ static int pch_can_resume(struct pci_dev *pdev)
>>  pch_can_set_optmode(priv);
>>
>>  /* Enabling the transmit buffer. */
>> - for (i = PCH_TX_OBJ_START; i <= PCH_TX_OBJ_END; i++)
>> + for (i = PCH_TX_OBJ_START; i < PCH_TX_OBJ_END; i++)
>>  pch_can_set_rxtx(priv, i, priv->tx_enable[i], PCH_TX_IFREG);
>>
>>  /* Configuring the receive buffer and enabling them. */
>>
>
> This fix does not look correct too me. There are much more loop using
> "i <= PCH_TX_OBJ_END" and the message numbering is from 1..32. Therefore
> using "priv->tx_enable[i - 1]" seems more appropriate to me. Tomaya,
> could you please check.
>
> Thanks,
>
> Wolfgang.
>
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