[PATCH 5.11 311/601] scsi: lpfc: Fix null pointer dereference in lpfc_prep_els_iocb()

Greg Kroah-Hartman
2021-05-12T17:31:07Z

From: James Smart <jsmart2021@gmail.com>

[ Upstream commit 8dd1c125f7f838abad009b64bff5f0a11afe3cb6 ]

It is possible to call lpfc_issue_els_plogi() passing a did for which no
matching ndlp is found. A call is then made to lpfc_prep_els_iocb() with a
null pointer to a lpfc_nodelist structure resulting in a null pointer
dereference.

Fix by returning an error status if no valid ndlp is found. Fix up comments
regarding ndlp reference counting.

Link: https://lore.kernel.org/r/20210301171821.3427-10-jsmart2021@gmail.com
Fixes: 4430f7fd09ec ("scsi: lpfc: Rework locations of ndlp reference taking")
Co-developed-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/lpfc/lpfc_els.c | 50 +++++++++++++++++-------------------
1 file changed, 24 insertions(+), 26 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index 2dce17827504..7359d4f118df 100644
--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -1,7 +1,7 @@
/*******************************************************************
* This file is part of the Emulex Linux Device Driver for *
* Fibre Channel Host Bus Adapters. *
- * Copyright (C) 2017-2020 Broadcom. All Rights Reserved. The term *
+ * Copyright (C) 2017-2021 Broadcom. All Rights Reserved. The term *
* “Broadcom” refers to Broadcom Inc. and/or its subsidiaries. *
* Copyright (C) 2004-2016 Emulex. All rights reserved. *
* EMULEX and SLI are trademarks of Emulex. *
@@ -2041,13 +2041,12 @@ out_freeiocb:
* This routine issues a Port Login (PLOGI) command to a remote N_Port
* (with the @did) for a @vport. Before issuing a PLOGI to a remote N_Port,
* the ndlp with the remote N_Port DID must exist on the @vport's ndlp list.
- * This routine constructs the proper feilds of the PLOGI IOCB and invokes
+ * This routine constructs the proper fields of the PLOGI IOCB and invokes
* the lpfc_sli_issue_iocb() routine to send out PLOGI ELS command.
*
- * Note that, in lpfc_prep_els_iocb() routine, the reference count of ndlp
- * will be incremented by 1 for holding the ndlp and the reference to ndlp
- * will be stored into the context1 field of the IOCB for the completion
- * callback function to the PLOGI ELS command.
+ * Note that the ndlp reference count will be incremented by 1 for holding
+ * the ndlp and the reference to ndlp will be stored into the context1 field
+ * of the IOCB for the completion callback function to the PLOGI ELS command.
*
* Return code
* 0 - Successfully issued a plogi for @vport
@@ -2065,29 +2064,28 @@ lpfc_issue_els_plogi(struct lpfc_vport *vport, uint32_t did, uint8_t retry)
int ret;

ndlp = lpfc_findnode_did(vport, did);
+ if (!ndlp)
+ return 1;

- if (ndlp) {
- /* Defer the processing of the issue PLOGI until after the
- * outstanding UNREG_RPI mbox command completes, unless we
- * are going offline. This logic does not apply for Fabric DIDs
- */
- if ((ndlp->nlp_flag & NLP_UNREG_INP) &&
- ((ndlp->nlp_DID & Fabric_DID_MASK) != Fabric_DID_MASK) &&
- !(vport->fc_flag & FC_OFFLINE_MODE)) {
- lpfc_printf_vlog(vport, KERN_INFO, LOG_DISCOVERY,
- "4110 Issue PLOGI x%x deferred "
- "on NPort x%x rpi x%x Data: x%px\n",
- ndlp->nlp_defer_did, ndlp->nlp_DID,
- ndlp->nlp_rpi, ndlp);
-
- /* We can only defer 1st PLOGI */
- if (ndlp->nlp_defer_did == NLP_EVT_NOTHING_PENDING)
- ndlp->nlp_defer_did = did;
- return 0;
- }
+ /* Defer the processing of the issue PLOGI until after the
+ * outstanding UNREG_RPI mbox command completes, unless we
+ * are going offline. This logic does not apply for Fabric DIDs
+ */
+ if ((ndlp->nlp_flag & NLP_UNREG_INP) &&
+ ((ndlp->nlp_DID & Fabric_DID_MASK) != Fabric_DID_MASK) &&
+ !(vport->fc_flag & FC_OFFLINE_MODE)) {
+ lpfc_printf_vlog(vport, KERN_INFO, LOG_DISCOVERY,
+ "4110 Issue PLOGI x%x deferred "
+ "on NPort x%x rpi x%x Data: x%px\n",
+ ndlp->nlp_defer_did, ndlp->nlp_DID,
+ ndlp->nlp_rpi, ndlp);
+
+ /* We can only defer 1st PLOGI */
+ if (ndlp->nlp_defer_did == NLP_EVT_NOTHING_PENDING)
+ ndlp->nlp_defer_did = did;
+ return 0;
}

- /* If ndlp is not NULL, we will bump the reference count on it */
cmdsize = (sizeof(uint32_t) + sizeof(struct serv_parm));
elsiocb = lpfc_prep_els_iocb(vport, 1, cmdsize, retry, ndlp, did,
ELS_CMD_PLOGI);
--
2.30.2