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Date:   Wed, 4 Aug 2021 23:20:04 -0500
From:   "Gustavo A. R. Silva" <gustavoars@kernel.org>
To:     linux-kernel@vger.kernel.org
Cc:     Kashyap Desai <kashyap.desai@broadcom.com>,
        Sumit Saxena <sumit.saxena@broadcom.com>,
        Shivasharan S <shivasharan.srikanteshwara@broadcom.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        megaraidlinux.pdl@broadcom.com, linux-scsi@vger.kernel.org,
        linux-hardening@vger.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>
Subject: [PATCH v2 3/4][next] scsi: megaraid_sas: Replace one-element array
 with flexible-array member in MR_DRV_RAID_MAP
Message-ID: <b43d4083d9788bb746dc0b2205d6a67ebb609b0d.1628136510.git.gustavoars@kernel.org>
References: <cover.1628136510.git.gustavoars@kernel.org>
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In-Reply-To: <cover.1628136510.git.gustavoars@kernel.org>
Precedence: bulk

Replace one-element array with a flexible-array member in struct
MR_DRV_RAID_MAP and use the flex_array_size() helper.

This helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines
on memcpy().

Link: https://en.wikipedia.org/wiki/Flexible_array_member
Link: https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays
Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/109
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v2:
 - None.

 drivers/scsi/megaraid/megaraid_sas_fp.c     | 6 +++---
 drivers/scsi/megaraid/megaraid_sas_fusion.h | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_fp.c b/drivers/scsi/megaraid/megaraid_sas_fp.c
index da1cad1ee123..9cb36ef96c2c 100644
--- a/drivers/scsi/megaraid/megaraid_sas_fp.c
+++ b/drivers/scsi/megaraid/megaraid_sas_fp.c
@@ -229,8 +229,8 @@ static int MR_PopulateDrvRaidMap(struct megasas_instance *instance, u64 map_id)
 					le32_to_cpu(desc_table->raid_map_desc_offset));
 				memcpy(pDrvRaidMap->ldSpanMap,
 				       fw_map_dyn->ld_span_map,
-				       sizeof(struct MR_LD_SPAN_MAP) *
-				       le32_to_cpu(desc_table->raid_map_desc_elements));
+				       flex_array_size(pDrvRaidMap, ldSpanMap,
+				       le32_to_cpu(desc_table->raid_map_desc_elements)));
 			break;
 			default:
 				dev_dbg(&instance->pdev->dev, "wrong number of desctableElements %d\n",
@@ -254,7 +254,7 @@ static int MR_PopulateDrvRaidMap(struct megasas_instance *instance, u64 map_id)
 			pDrvRaidMap->ldTgtIdToLd[i] =
 				(u16)fw_map_ext->ldTgtIdToLd[i];
 		memcpy(pDrvRaidMap->ldSpanMap, fw_map_ext->ldSpanMap,
-		       sizeof(struct MR_LD_SPAN_MAP) * ld_count);
+		       flex_array_size(pDrvRaidMap, ldSpanMap, ld_count));
 		memcpy(pDrvRaidMap->arMapInfo, fw_map_ext->arMapInfo,
 		       sizeof(struct MR_ARRAY_INFO) * MAX_API_ARRAYS_EXT);
 		memcpy(pDrvRaidMap->devHndlInfo, fw_map_ext->devHndlInfo,
diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.h b/drivers/scsi/megaraid/megaraid_sas_fusion.h
index 9adb8b30f422..5fe2f7a6eebe 100644
--- a/drivers/scsi/megaraid/megaraid_sas_fusion.h
+++ b/drivers/scsi/megaraid/megaraid_sas_fusion.h
@@ -1182,7 +1182,7 @@ struct MR_DRV_RAID_MAP {
 		devHndlInfo[MAX_RAIDMAP_PHYSICAL_DEVICES_DYN];
 	u16 ldTgtIdToLd[MAX_LOGICAL_DRIVES_DYN];
 	struct MR_ARRAY_INFO arMapInfo[MAX_API_ARRAYS_DYN];
-	struct MR_LD_SPAN_MAP      ldSpanMap[1];
+	struct MR_LD_SPAN_MAP      ldSpanMap[];
 
 };
 
-- 
2.27.0