[patch] sata_sil24: memset() overflow

[patch] sata_sil24: memset() overflow

[Dan Carpenter]

cb->atapi.cdb is an array of 16 u8 elements.  The call too memset() 
would set the first part of the sge array to zero as well.  It's not
a packed struct. 

This one has been around for five years.  I found it with Smatch.  I
think the reason no one has seen it before is because we normally call
sil24_fill_sg() and that overwrites sge with proper information?

Signed-off-by: Dan Carpenter <error27@gmail.com>
---
I don't have this hardware myself so I can't test it.  Sorry. :(

diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index e925051..9e459eb 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -865,7 +865,7 @@ static void sil24_qc_prep(struct ata_queued_cmd *qc)
 	} else {
 		prb = &cb->atapi.prb;
 		sge = cb->atapi.sge;
-		memset(cb->atapi.cdb, 0, 32);
+		memset(cb->atapi.cdb, 0, sizeof(cb->atapi.cdb));
 		memcpy(cb->atapi.cdb, qc->cdb, qc->dev->cdb_len);
 
 		if (ata_is_data(qc->tf.protocol)) {

Re: [patch] sata_sil24: memset() overflow

[Tejun Heo]

On 06/09/2010 02:01 PM, Dan Carpenter wrote:
> cb->atapi.cdb is an array of 16 u8 elements.  The call too memset() 
> would set the first part of the sge array to zero as well.  It's not
> a packed struct. 
> 
> This one has been around for five years.  I found it with Smatch.  I
> think the reason no one has seen it before is because we normally call
> sil24_fill_sg() and that overwrites sge with proper information?

Yeah, the table is built after the memset so it doesn't really break
anything but still where did that 32 come from?  :-)

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

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

Re: [patch] sata_sil24: memset() overflow

[Jeff Garzik]

On 06/09/2010 08:01 AM, Dan Carpenter wrote:
> cb->atapi.cdb is an array of 16 u8 elements.  The call too memset()
> would set the first part of the sge array to zero as well.  It's not
> a packed struct.
>
> This one has been around for five years.  I found it with Smatch.  I
> think the reason no one has seen it before is because we normally call
> sil24_fill_sg() and that overwrites sge with proper information?
>
> Signed-off-by: Dan Carpenter<error27@gmail.com>
> ---
> I don't have this hardware myself so I can't test it.  Sorry. :(
>
> diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
> index e925051..9e459eb 100644
> --- a/drivers/ata/sata_sil24.c
> +++ b/drivers/ata/sata_sil24.c
> @@ -865,7 +865,7 @@ static void sil24_qc_prep(struct ata_queued_cmd *qc)
>   	} else {
>   		prb =&cb->atapi.prb;
>   		sge = cb->atapi.sge;
> -		memset(cb->atapi.cdb, 0, 32);
> +		memset(cb->atapi.cdb, 0, sizeof(cb->atapi.cdb));
>   		memcpy(cb->atapi.cdb, qc->cdb, qc->dev->cdb_len);

applied