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* [patch 1/2] memstick: use after free in msb_disk_release()
@ 2012-09-29  7:11 Dan Carpenter
  2012-09-29 22:09 ` Maxim Levitsky
  0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2012-09-29  7:11 UTC (permalink / raw)
  To: Maxim Levitsky; +Cc: linux-kernel, kernel-janitors, Andrew Morton, Jens Axboe

The original code dereferenced "msb" after freeing it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/memstick/core/ms_block.c b/drivers/memstick/core/ms_block.c
index c815fe5..a8e8915 100644
--- a/drivers/memstick/core/ms_block.c
+++ b/drivers/memstick/core/ms_block.c
@@ -1983,9 +1983,9 @@ static int msb_disk_release(struct gendisk *disk)
 			msb->usage_count--;
 
 		if (!msb->usage_count) {
-			kfree(msb);
 			disk->private_data = NULL;
 			idr_remove(&msb_disk_idr, msb->disk_id);
+			kfree(msb);
 			put_disk(disk);
 		}
 	}

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [patch 1/2] memstick: use after free in msb_disk_release()
  2012-09-29  7:11 [patch 1/2] memstick: use after free in msb_disk_release() Dan Carpenter
@ 2012-09-29 22:09 ` Maxim Levitsky
  0 siblings, 0 replies; 2+ messages in thread
From: Maxim Levitsky @ 2012-09-29 22:09 UTC (permalink / raw)
  To: Dan Carpenter; +Cc: linux-kernel, kernel-janitors, Andrew Morton, Jens Axboe

On Sat, 2012-09-29 at 10:11 +0300, Dan Carpenter wrote: 
> The original code dereferenced "msb" after freeing it.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/memstick/core/ms_block.c b/drivers/memstick/core/ms_block.c
> index c815fe5..a8e8915 100644
> --- a/drivers/memstick/core/ms_block.c
> +++ b/drivers/memstick/core/ms_block.c
> @@ -1983,9 +1983,9 @@ static int msb_disk_release(struct gendisk *disk)
>  			msb->usage_count--;
>  
>  		if (!msb->usage_count) {
> -			kfree(msb);
>  			disk->private_data = NULL;
>  			idr_remove(&msb_disk_idr, msb->disk_id);
> +			kfree(msb);
>  			put_disk(disk);
>  		}
>  	}

Oops, I added this bug in latest iteration, when removed support for
major.
Acked-by: Maxim Levitsky <maximlevitsly@gmail.com>

Best regards,
Maxim Levitsky


^ permalink raw reply	[flat|nested] 2+ messages in thread

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