[PATCH v1] mmc: card: fixing an false identification of SANITIZE command

[PATCH v1] mmc: card: fixing an false identification of SANITIZE command

[Yaniv Gardi]

Inside the routine mmc_blk_ioctl_cmd() the sanitize command is
identified according to the value of bits 16-23 of the argument.

but what happens if a different command is sent, and only by chance,
bits 16-23 contain the value of SANITIZE command ?
In that case a SANITIZE command will be falsely identified.
In order to prevent such a case, the condition is expanded and
now it also checks the opcode itself, and verifies that it is an
MMC_SWITCH opcode.

Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
---
 drivers/mmc/card/block.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index c900d28..9775ae7 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -542,7 +542,9 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
 			goto cmd_rel_host;
 	}
 
-	if (MMC_EXTRACT_INDEX_FROM_ARG(cmd.arg) == EXT_CSD_SANITIZE_START) {
+	if ((MMC_EXTRACT_INDEX_FROM_ARG(cmd.arg) == EXT_CSD_SANITIZE_START) &&
+	     (cmd.opcode == MMC_SWITCH)) {
+
 		err = ioctl_do_sanitize(card);
 
 		if (err)
-- 
1.7.6

Re: [PATCH v1] mmc: card: fixing an false identification of SANITIZE command

[Chris Ball]

Hi Yaniv,

On Wed, Jun 05 2013, Yaniv Gardi wrote:
> Inside the routine mmc_blk_ioctl_cmd() the sanitize command is
> identified according to the value of bits 16-23 of the argument.
>
> but what happens if a different command is sent, and only by chance,
> bits 16-23 contain the value of SANITIZE command ?
> In that case a SANITIZE command will be falsely identified.
> In order to prevent such a case, the condition is expanded and
> now it also checks the opcode itself, and verifies that it is an
> MMC_SWITCH opcode.
>
> Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
> ---
>  drivers/mmc/card/block.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index c900d28..9775ae7 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -542,7 +542,9 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
>  			goto cmd_rel_host;
>  	}
>  
> -	if (MMC_EXTRACT_INDEX_FROM_ARG(cmd.arg) == EXT_CSD_SANITIZE_START) {
> +	if ((MMC_EXTRACT_INDEX_FROM_ARG(cmd.arg) == EXT_CSD_SANITIZE_START) &&
> +	     (cmd.opcode == MMC_SWITCH)) {
> +
>  		err = ioctl_do_sanitize(card);
>  
>  		if (err)

Thanks, pushed to mmc-next for 3.11.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child