Commit 258aad75 authored by Mike Christie's avatar Mike Christie Committed by Martin K. Petersen
Browse files

scsi: iscsi: Fix iscsi_task use after free 

Commit d39df158 ("scsi: iscsi: Have abort handler get ref to conn")
added iscsi_get_conn()/iscsi_put_conn() calls during abort handling but
then also changed the handling of the case where we detect an already
completed task where we now end up doing a goto to the common put/cleanup
code. This results in a iscsi_task use after free, because the common
cleanup code will do a put on the iscsi_task.

This reverts the goto and moves the iscsi_get_conn() to after we've checked
if the iscsi_task is valid.

Link: https://lore.kernel.org/r/20211004210608.9962-1-michael.christie@oracle.com


Fixes: d39df158 ("scsi: iscsi: Have abort handler get ref to conn")
Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 69a3a7bc

drivers/scsi/libiscsi.c

+9 −6
Original line number Diff line number Diff line
@@ -2281,11 +2281,6 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) 
		return FAILED;

	}



	conn = session->leadconn;

	iscsi_get_conn(conn->cls_conn);

	conn->eh_abort_cnt++;

	age = session->age;



	spin_lock(&session->back_lock);

	task = (struct iscsi_task *)sc->SCp.ptr;

	if (!task || !task->sc) {
@@ -2293,8 +2288,16 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) 
		ISCSI_DBG_EH(session, "sc completed while abort in progress\n");



		spin_unlock(&session->back_lock);

		goto success;

		spin_unlock_bh(&session->frwd_lock);

		mutex_unlock(&session->eh_mutex);

		return SUCCESS;

	}



	conn = session->leadconn;

	iscsi_get_conn(conn->cls_conn);

	conn->eh_abort_cnt++;

	age = session->age;



	ISCSI_DBG_EH(session, "aborting [sc %p itt 0x%x]\n", sc, task->itt);

	__iscsi_get_task(task);

	spin_unlock(&session->back_lock);