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From:   Stephen Kitt <steve@sk2.org>
To:     hare@suse.com, axboe@kernel.dk, jejb@linux.vnet.ibm.com,
        martin.petersen@oracle.com
Cc:     linux-scsi@vger.kernel.org, kernel-hardening@lists.openwall.com,
        linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        Stephen Kitt <steve@sk2.org>
Subject: [PATCH] device_handler: remove VLAs
Date:   Fri,  9 Mar 2018 23:32:11 +0100
Message-Id: <20180309223211.20473-1-steve@sk2.org>
In-Reply-To: <20180309232933.14e39858@heffalump.sk2.org>
References: <20180309232933.14e39858@heffalump.sk2.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In preparation to enabling -Wvla, remove VLAs and replace them with
fixed-length arrays instead.

scsi_dh_{alua,emc,rdac} use variable-length array declarations to
store command blocks, with the appropriate size as determined by
COMMAND_SIZE. This patch replaces these with fixed-sized arrays using
MAX_COMMAND_SIZE, so that the array size can be determined at compile
time.

This was prompted by https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Stephen Kitt <steve@sk2.org>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 8 ++++----
 drivers/scsi/device_handler/scsi_dh_emc.c  | 2 +-
 drivers/scsi/device_handler/scsi_dh_rdac.c | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 4b44325d1a82..982a52528a1c 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -138,12 +138,12 @@ static void release_port_group(struct kref *kref)
 static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
 		       int bufflen, struct scsi_sense_hdr *sshdr, int flags)
 {
-	u8 cdb[COMMAND_SIZE(MAINTENANCE_IN)];
+	u8 cdb[MAX_COMMAND_SIZE];
 	int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
 		REQ_FAILFAST_DRIVER;
 
 	/* Prepare the command. */
-	memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_IN));
+	memset(cdb, 0x0, MAX_COMMAND_SIZE);
 	cdb[0] = MAINTENANCE_IN;
 	if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP))
 		cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
@@ -166,7 +166,7 @@ static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
 static int submit_stpg(struct scsi_device *sdev, int group_id,
 		       struct scsi_sense_hdr *sshdr)
 {
-	u8 cdb[COMMAND_SIZE(MAINTENANCE_OUT)];
+	u8 cdb[MAX_COMMAND_SIZE];
 	unsigned char stpg_data[8];
 	int stpg_len = 8;
 	int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
@@ -178,7 +178,7 @@ static int submit_stpg(struct scsi_device *sdev, int group_id,
 	put_unaligned_be16(group_id, &stpg_data[6]);
 
 	/* Prepare the command. */
-	memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_OUT));
+	memset(cdb, 0x0, MAX_COMMAND_SIZE);
 	cdb[0] = MAINTENANCE_OUT;
 	cdb[1] = MO_SET_TARGET_PGS;
 	put_unaligned_be32(stpg_len, &cdb[6]);
diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c
index 6a2792f3a37e..95c47909a58f 100644
--- a/drivers/scsi/device_handler/scsi_dh_emc.c
+++ b/drivers/scsi/device_handler/scsi_dh_emc.c
@@ -249,7 +249,7 @@ static int send_trespass_cmd(struct scsi_device *sdev,
 			    struct clariion_dh_data *csdev)
 {
 	unsigned char *page22;
-	unsigned char cdb[COMMAND_SIZE(MODE_SELECT)];
+	unsigned char cdb[MAX_COMMAND_SIZE];
 	int err, res = SCSI_DH_OK, len;
 	struct scsi_sense_hdr sshdr;
 	u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index 7af31a1247ee..d27fabae8ddd 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -533,7 +533,7 @@ static void send_mode_select(struct work_struct *work)
 	int err = SCSI_DH_OK, retry_cnt = RDAC_RETRY_COUNT;
 	struct rdac_queue_data *tmp, *qdata;
 	LIST_HEAD(list);
-	unsigned char cdb[COMMAND_SIZE(MODE_SELECT_10)];
+	unsigned char cdb[MAX_COMMAND_SIZE];
 	struct scsi_sense_hdr sshdr;
 	unsigned int data_size;
 	u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
-- 
2.11.0