[PATCH v5] qla2xxx: Fix unbound NVME response length

[Himanshu Madhani <hmadhani@marvell.com>]

From: Arun Easi <aeasi@marvell.com>

On certain cases when response length is less than 32, NVME response data
is supplied inline in IOCB. This is indicated by some combination of state
flags. There was an instance when a high, and incorrect, response length was
indicated causing driver to overrun buffers. Fix this by checking and
limiting the response payload length.

Fixes: 7401bc18d1ee3 ("scsi: qla2xxx: Add FC-NVMe command handling")
Cc: stable@vger.kernel.org
Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
---
Hi Martin,

We discovered issue with our newer Gen7 adapter when response length
happens to be larger than 32 bytes, could result into crash.

Please apply this to 5.5/scsi-fixes branch at your earliest convenience.

Changes from v4 -> v5

o Added WARN_ONCE and moved it under ql_dbg bits to avoid excessive logging

Changes from v3 -> v4

o use "sizeof(struct nvme_fc_ersp_iu)" in missed place.

Changes from v2 -> v3

o Use "sizeof(struct nvme_fc_ersp_iu)" to indicate response payload size.

Changes from v1 -> v2

o Fixed the tag for stable.
o Removed logit which got spilled from other patch to prevent compile failure.

Thanks,
Himanshu
---
 drivers/scsi/qla2xxx/qla_dbg.c |  6 ------
 drivers/scsi/qla2xxx/qla_dbg.h |  6 ++++++
 drivers/scsi/qla2xxx/qla_isr.c | 12 ++++++++++++
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_dbg.c b/drivers/scsi/qla2xxx/qla_dbg.c
index e5500bba06ca..88a56e8480f7 100644
--- a/drivers/scsi/qla2xxx/qla_dbg.c
+++ b/drivers/scsi/qla2xxx/qla_dbg.c
@@ -2519,12 +2519,6 @@ qla83xx_fw_dump(scsi_qla_host_t *vha, int hardware_locked)
 /*                         Driver Debug Functions.                          */
 /****************************************************************************/
 
-static inline int
-ql_mask_match(uint level)
-{
-	return (level & ql2xextended_error_logging) == level;
-}
-
 /*
  * This function is for formatting and logging debug information.
  * It is to be used when vha is available. It formats the message
diff --git a/drivers/scsi/qla2xxx/qla_dbg.h b/drivers/scsi/qla2xxx/qla_dbg.h
index bb01b680ce9f..433e95502808 100644
--- a/drivers/scsi/qla2xxx/qla_dbg.h
+++ b/drivers/scsi/qla2xxx/qla_dbg.h
@@ -374,3 +374,9 @@ extern int qla24xx_dump_ram(struct qla_hw_data *, uint32_t, uint32_t *,
 extern void qla24xx_pause_risc(struct device_reg_24xx __iomem *,
 	struct qla_hw_data *);
 extern int qla24xx_soft_reset(struct qla_hw_data *);
+
+static inline int
+ql_mask_match(uint level)
+{
+	return (level & ql2xextended_error_logging) == level;
+}
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index e7bad0bfffda..e40705d38cea 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -1939,6 +1939,18 @@ static void qla24xx_nvme_iocb_entry(scsi_qla_host_t *vha, struct req_que *req,
 		inbuf = (uint32_t *)&sts->nvme_ersp_data;
 		outbuf = (uint32_t *)fd->rspaddr;
 		iocb->u.nvme.rsp_pyld_len = le16_to_cpu(sts->nvme_rsp_pyld_len);
+		if (unlikely(iocb->u.nvme.rsp_pyld_len >
+		    sizeof(struct nvme_fc_ersp_iu))) {
+			if (ql_mask_match(ql_dbg_io)) {
+				WARN_ONCE(1, "Unexpected response payload length %u.\n",
+				    iocb->u.nvme.rsp_pyld_len);
+				ql_log(ql_log_warn, fcport->vha, 0x5100,
+				    "Unexpected response payload length %u.\n",
+				    iocb->u.nvme.rsp_pyld_len);
+			}
+			iocb->u.nvme.rsp_pyld_len =
+			    sizeof(struct nvme_fc_ersp_iu);
+		}
 		iter = iocb->u.nvme.rsp_pyld_len >> 2;
 		for (; iter; iter--)
 			*outbuf++ = swab32(*inbuf++);
-- 
2.12.0