[PATCH 5.15 024/106] scsi: lpfc: Resolve NULL ptr dereference after an ELS LOGO is aborted

[Greg Kroah-Hartman]

From: James Smart <jsmart2021@xxxxxxxxx>

[ Upstream commit b1b3440f437b75fb2a9b0cfe58df461e40eca474 ]

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@xxxxxxxxx
Co-developed-by: Justin Tee <justin.tee@xxxxxxxxxxxx>
Signed-off-by: Justin Tee <justin.tee@xxxxxxxxxxxx>
Signed-off-by: James Smart <jsmart2021@xxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/lpfc/lpfc_els.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index ce28c4a30460..5f44a0763f37 100644
--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -2955,18 +2955,10 @@ lpfc_cmpl_els_logo(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		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
@@ -2993,6 +2985,10 @@ lpfc_cmpl_els_logo(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 				 ndlp->nlp_DID, irsp->ulpStatus,
 				 irsp->un.ulpWord[4], irsp->ulpTimeout,
 				 vport->num_disc_nodes);
+
+		lpfc_els_free_iocb(phba, cmdiocb);
+		lpfc_nlp_put(ndlp);
+
 		lpfc_disc_start(vport);
 		return;
 	}
@@ -3009,6 +3005,10 @@ lpfc_cmpl_els_logo(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		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);
 }
 
 /**
-- 
2.35.1