fc_exch_release(ep) will decrease the ep's reference count. When the
reference count reaches zero, it is freed. But ep is still used in the
following code, which will lead to a use after free.
We should return the function after the call of fc_exch_release() to
avoid use after free.
Signed-off-by: Jianglei Nie <[email protected]>
---
drivers/scsi/libfc/fc_exch.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 841000445b9a..aa223db4cf53 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -1701,6 +1701,7 @@ static void fc_exch_abts_resp(struct fc_exch *ep, struct fc_frame *fp)
if (cancel_delayed_work_sync(&ep->timeout_work)) {
FC_EXCH_DBG(ep, "Exchange timer canceled due to ABTS response\n");
fc_exch_release(ep); /* release from pending timer hold */
+ return;
}
spin_lock_bh(&ep->ex_lock);
--
2.25.1
On 3/3/22 02:51, Jianglei Nie wrote:
> fc_exch_release(ep) will decrease the ep's reference count. When the
> reference count reaches zero, it is freed. But ep is still used in the
> following code, which will lead to a use after free.
>
> We should return the function after the call of fc_exch_release() to
> avoid use after free.
>
> Signed-off-by: Jianglei Nie <[email protected]>
> ---
> drivers/scsi/libfc/fc_exch.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
> index 841000445b9a..aa223db4cf53 100644
> --- a/drivers/scsi/libfc/fc_exch.c
> +++ b/drivers/scsi/libfc/fc_exch.c
> @@ -1701,6 +1701,7 @@ static void fc_exch_abts_resp(struct fc_exch *ep, struct fc_frame *fp)
> if (cancel_delayed_work_sync(&ep->timeout_work)) {
> FC_EXCH_DBG(ep, "Exchange timer canceled due to ABTS response\n");
> fc_exch_release(ep); /* release from pending timer hold */
> + return;
> }
>
> spin_lock_bh(&ep->ex_lock);
Reviewed-by: Hannes Reinecke <[email protected]>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
[email protected] +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
Jianglei,
> fc_exch_release(ep) will decrease the ep's reference count. When the
> reference count reaches zero, it is freed. But ep is still used in the
> following code, which will lead to a use after free.
Applied to 5.18/scsi-staging, thanks!
--
Martin K. Petersen Oracle Linux Engineering
On Thu, 3 Mar 2022 09:51:15 +0800, Jianglei Nie wrote:
> fc_exch_release(ep) will decrease the ep's reference count. When the
> reference count reaches zero, it is freed. But ep is still used in the
> following code, which will lead to a use after free.
>
> We should return the function after the call of fc_exch_release() to
> avoid use after free.
>
> [...]
Applied to 5.18/scsi-queue, thanks!
[1/1] scsi: libfc: Fix use after free in fc_exch_abts_resp()
https://git.kernel.org/mkp/scsi/c/271add11994b
--
Martin K. Petersen Oracle Linux Engineering