From: James Smart <jsmart2021@gmail.com>

Date: Fri, 3 Jun 2022 10:43:25 -0700

Subject: scsi: lpfc: Resolve NULL ptr dereference after an ELS LOGO is aborted

Patch-mainline: v5.19-rc2

Git-commit: b1b3440f437b75fb2a9b0cfe58df461e40eca474

References: bsc#1201193

A use-after-free crash can occur after an ELS LOGO is aborted.

Specifically, a nodelist structure is freed and then

ndlp->vport->cfg_log_verbose is dereferenced in lpfc_nlp_get() when the

discovery state machine is mistakenly called a second time with

NLP_EVT_DEVICE_RM argument.

Rework lpfc_cmpl_els_logo() to prevent the duplicate calls to release a

nodelist structure.

Link: https://lore.kernel.org/r/20220603174329.63777-6-jsmart2021@gmail.com

Co-developed-by: Justin Tee <justin.tee@broadcom.com>

Signed-off-by: Justin Tee <justin.tee@broadcom.com>

Signed-off-by: James Smart <jsmart2021@gmail.com>

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Acked-by: Daniel Wagner <dwagner@suse.de>

---

 drivers/scsi/lpfc/lpfc_els.c |   21 +++++++++------------

 1 file changed, 9 insertions(+), 12 deletions(-)

--- a/drivers/scsi/lpfc/lpfc_els.c

+++ b/drivers/scsi/lpfc/lpfc_els.c

@@ -2998,10 +2998,7 @@ lpfc_cmpl_els_logo(struct lpfc_hba *phba

 				 ndlp->nlp_DID, ulp_status,

 				 ulp_word4);

-		/* Call NLP_EVT_DEVICE_RM if link is down or LOGO is aborted */

 		if (lpfc_error_lost_link(ulp_status, ulp_word4)) {

-			lpfc_disc_state_machine(vport, ndlp, cmdiocb,

-						NLP_EVT_DEVICE_RM);

 			skip_recovery = 1;

 			goto out;

 		}

@@ -3021,18 +3018,10 @@ lpfc_cmpl_els_logo(struct lpfc_hba *phba

 		spin_unlock_irq(&ndlp->lock);

 		lpfc_disc_state_machine(vport, ndlp, cmdiocb,

 					NLP_EVT_DEVICE_RM);

-		lpfc_els_free_iocb(phba, cmdiocb);

-		lpfc_nlp_put(ndlp);

-

-		/* Presume the node was released. */

-		return;

+		goto out_rsrc_free;

 	}

 out:

-	/* Driver is done with the IO.  */

-	lpfc_els_free_iocb(phba, cmdiocb);

-	lpfc_nlp_put(ndlp);

-

 	/* At this point, the LOGO processing is complete. NOTE: For a

 	 * pt2pt topology, we are assuming the NPortID will only change

 	 * on link up processing. For a LOGO / PLOGI initiated by the

@@ -3059,6 +3048,10 @@ lpfc_cmpl_els_logo(struct lpfc_hba *phba

 				 ndlp->nlp_DID, ulp_status,

 				 ulp_word4, tmo,

 				 vport->num_disc_nodes);

+

+		lpfc_els_free_iocb(phba, cmdiocb);

+		lpfc_nlp_put(ndlp);

+

 		lpfc_disc_start(vport);

 		return;

 	}

@@ -3075,6 +3068,10 @@ lpfc_cmpl_els_logo(struct lpfc_hba *phba

 		lpfc_disc_state_machine(vport, ndlp, cmdiocb,

 					NLP_EVT_DEVICE_RM);

 	}

+out_rsrc_free:

+	/* Driver is done with the I/O. */

+	lpfc_els_free_iocb(phba, cmdiocb);

+	lpfc_nlp_put(ndlp);

 }

 /**