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

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>

diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index 07f9a6e..3fababb 100644 (file)
--- 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, struct lpfc_iocbq *cmdiocb,
                                 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, 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
@@ -3059,6 +3048,10 @@ out:
                                 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 @@ out:
                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);
 }
 
 /**