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* [PATCH] scsi: fix use-after-free in scsi_init_io()
@ 2010-08-16 14:15 Tejun Heo
  2010-08-16 15:06 ` James Bottomley
  0 siblings, 1 reply; 3+ messages in thread
From: Tejun Heo @ 2010-08-16 14:15 UTC (permalink / raw)
  To: James Bottomley, Linux SCSI List; +Cc: stable

scsi_init_io() dereferences scsi_cmnd after putting it in the error
path leading to oops.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
---
 drivers/scsi/scsi_lib.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: block/drivers/scsi/scsi_lib.c
===================================================================
--- block.orig/drivers/scsi/scsi_lib.c
+++ block/drivers/scsi/scsi_lib.c
@@ -968,7 +968,9 @@ static int scsi_init_sgtable(struct requ
  */
 int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 {
+	struct request *req = cmd->request;
 	int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
+
 	if (error)
 		goto err_exit;

@@ -1012,7 +1014,7 @@ int scsi_init_io(struct scsi_cmnd *cmd,
 err_exit:
 	scsi_release_buffers(cmd);
 	scsi_put_command(cmd);
-	cmd->request->special = NULL;
+	req->special = NULL;
 	return error;
 }
 EXPORT_SYMBOL(scsi_init_io);

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] scsi: fix use-after-free in scsi_init_io()
  2010-08-16 15:06 ` James Bottomley
@ 2010-08-16 15:04   ` Tejun Heo
  0 siblings, 0 replies; 3+ messages in thread
From: Tejun Heo @ 2010-08-16 15:04 UTC (permalink / raw)
  To: James Bottomley; +Cc: Linux SCSI List, stable

Hello,

On 08/16/2010 05:06 PM, James Bottomley wrote:
> Thanks for the bug report.  The fix is a bit heavy handed; what about
> this?

Yeap, sure.  Looks good to me.

-- 
tejun

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] scsi: fix use-after-free in scsi_init_io()
  2010-08-16 14:15 [PATCH] scsi: fix use-after-free in scsi_init_io() Tejun Heo
@ 2010-08-16 15:06 ` James Bottomley
  2010-08-16 15:04   ` Tejun Heo
  0 siblings, 1 reply; 3+ messages in thread
From: James Bottomley @ 2010-08-16 15:06 UTC (permalink / raw)
  To: Tejun Heo; +Cc: Linux SCSI List, stable

On Mon, 2010-08-16 at 16:15 +0200, Tejun Heo wrote:
> scsi_init_io() dereferences scsi_cmnd after putting it in the error
> path leading to oops.  Fix it.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: stable@kernel.org
> ---
>  drivers/scsi/scsi_lib.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> Index: block/drivers/scsi/scsi_lib.c
> ===================================================================
> --- block.orig/drivers/scsi/scsi_lib.c
> +++ block/drivers/scsi/scsi_lib.c
> @@ -968,7 +968,9 @@ static int scsi_init_sgtable(struct requ
>   */
>  int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
>  {
> +	struct request *req = cmd->request;
>  	int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
> +
>  	if (error)
>  		goto err_exit;
> 
> @@ -1012,7 +1014,7 @@ int scsi_init_io(struct scsi_cmnd *cmd,
>  err_exit:
>  	scsi_release_buffers(cmd);
>  	scsi_put_command(cmd);
> -	cmd->request->special = NULL;
> +	req->special = NULL;

Thanks for the bug report.  The fix is a bit heavy handed; what about
this?

James

---

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9ade720..ee02d38 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1011,8 +1011,8 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 
 err_exit:
 	scsi_release_buffers(cmd);
-	scsi_put_command(cmd);
 	cmd->request->special = NULL;
+	scsi_put_command(cmd);
 	return error;
 }
 EXPORT_SYMBOL(scsi_init_io);



^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2010-08-16 15:07 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2010-08-16 14:15 [PATCH] scsi: fix use-after-free in scsi_init_io() Tejun Heo
2010-08-16 15:06 ` James Bottomley
2010-08-16 15:04   ` Tejun Heo

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