[PATCH v4 3/7] target: consistently null-terminate t10_wwn.model

[David Disseldorp <ddiss@suse.de>]

The pscsi_set_inquiry_info() and emulate_model_alias_store() codepaths
don't currently explicitly null-terminate t10_wwn.model.
Add an extra byte to the t10_wwn.model buffer and perform null string
termination in all cases.

dev_set_t10_wwn_model_alias() continues to truncate at the same length
to avoid changing the model string for existing deployments.

Signed-off-by: David Disseldorp <ddiss@suse.de>
---
 drivers/target/target_core_configfs.c | 8 +++++---
 drivers/target/target_core_device.c   | 8 +++++---
 drivers/target/target_core_pscsi.c    | 6 ++++--
 drivers/target/target_core_spc.c      | 2 +-
 drivers/target/target_core_stat.c     | 4 ++--
 include/target/target_core_base.h     | 3 ++-
 6 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index f6b1549f4142..9f49b1afd685 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -613,12 +613,12 @@ static void dev_set_t10_wwn_model_alias(struct se_device *dev)
 	const char *configname;
 
 	configname = config_item_name(&dev->dev_group.cg_item);
-	if (strlen(configname) >= 16) {
+	if (strlen(configname) >= INQUIRY_MODEL_LEN) {
 		pr_warn("dev[%p]: Backstore name '%s' is too long for "
 			"INQUIRY_MODEL, truncating to 16 bytes\n", dev,
 			configname);
 	}
-	snprintf(&dev->t10_wwn.model[0], 16, "%s", configname);
+	snprintf(&dev->t10_wwn.model[0], INQUIRY_MODEL_LEN, "%s", configname);
 }
 
 static ssize_t emulate_model_alias_store(struct config_item *item,
@@ -640,11 +640,13 @@ static ssize_t emulate_model_alias_store(struct config_item *item,
 	if (ret < 0)
 		return ret;
 
+	BUILD_BUG_ON(sizeof(dev->t10_wwn.model) != INQUIRY_MODEL_LEN + 1);
 	if (flag) {
 		dev_set_t10_wwn_model_alias(dev);
 	} else {
 		strncpy(&dev->t10_wwn.model[0],
-			dev->transport->inquiry_prod, 16);
+			dev->transport->inquiry_prod, INQUIRY_MODEL_LEN);
+		dev->t10_wwn.model[INQUIRY_MODEL_LEN] = '\0';
 	}
 	da->emulate_model_alias = flag;
 	return count;
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index fe4c4db51137..0d7382efb2d4 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -720,7 +720,7 @@ void core_dev_free_initiator_node_lun_acl(
 static void scsi_dump_inquiry(struct se_device *dev)
 {
 	struct t10_wwn *wwn = &dev->t10_wwn;
-	char buf[17];
+	char buf[INQUIRY_MODEL_LEN + 1];
 	int i, device_type;
 	/*
 	 * Print Linux/SCSI style INQUIRY formatting to the kernel ring buffer
@@ -733,7 +733,7 @@ static void scsi_dump_inquiry(struct se_device *dev)
 	buf[i] = '\0';
 	pr_debug("  Vendor: %s\n", buf);
 
-	for (i = 0; i < 16; i++)
+	for (i = 0; i < INQUIRY_MODEL_LEN; i++)
 		if (wwn->model[i] >= 0x20)
 			buf[i] = wwn->model[i];
 		else
@@ -1009,11 +1009,13 @@ int target_configure_device(struct se_device *dev)
 	 * passthrough because this is being provided by the backend LLD.
 	 */
 	BUILD_BUG_ON(sizeof(dev->t10_wwn.vendor) != INQUIRY_VENDOR_LEN + 1);
+	BUILD_BUG_ON(sizeof(dev->t10_wwn.model) != INQUIRY_MODEL_LEN + 1);
 	if (!(dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)) {
 		strncpy(&dev->t10_wwn.vendor[0], "LIO-ORG", INQUIRY_VENDOR_LEN);
 		dev->t10_wwn.vendor[INQUIRY_VENDOR_LEN] = '\0';
 		strncpy(&dev->t10_wwn.model[0],
-			dev->transport->inquiry_prod, 16);
+			dev->transport->inquiry_prod, INQUIRY_MODEL_LEN);
+		dev->t10_wwn.model[INQUIRY_MODEL_LEN] = '\0';
 		strncpy(&dev->t10_wwn.revision[0],
 			dev->transport->inquiry_rev, 4);
 	}
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index ee65b5bb674c..1633babc2d4e 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -193,7 +193,9 @@ pscsi_set_inquiry_info(struct scsi_device *sdev, struct t10_wwn *wwn)
 	BUILD_BUG_ON(sizeof(wwn->vendor) != INQUIRY_VENDOR_LEN + 1);
 	memcpy(&wwn->vendor[0], &buf[8], INQUIRY_VENDOR_LEN);
 	wwn->vendor[INQUIRY_VENDOR_LEN] = '\0';
-	memcpy(&wwn->model[0], &buf[16], sizeof(wwn->model));
+	BUILD_BUG_ON(sizeof(wwn->model) != INQUIRY_MODEL_LEN + 1);
+	memcpy(&wwn->model[0], &buf[16], INQUIRY_MODEL_LEN);
+	wwn->model[INQUIRY_MODEL_LEN] = '\0';
 	memcpy(&wwn->revision[0], &buf[32], sizeof(wwn->revision));
 }
 
@@ -835,7 +837,7 @@ static ssize_t pscsi_show_configfs_dev_params(struct se_device *dev, char *b)
 				bl += sprintf(b + bl, " ");
 		}
 		bl += sprintf(b + bl, " Model: ");
-		for (i = 0; i < 16; i++) {
+		for (i = 0; i < INQUIRY_MODEL_LEN; i++) {
 			if (ISPRINT(sd->model[i]))   /* printable character ? */
 				bl += sprintf(b + bl, "%c", sd->model[i]);
 			else
diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index c37dd36ec77d..78eddee4b6e6 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -116,7 +116,7 @@ spc_emulate_inquiry_std(struct se_cmd *cmd, unsigned char *buf)
 	memset(&buf[8], 0x20, 8 + 16 + 4);
 	memcpy(&buf[8], "LIO-ORG", sizeof("LIO-ORG") - 1);
 	memcpy(&buf[16], dev->t10_wwn.model,
-	       strnlen(dev->t10_wwn.model, 16));
+	       strnlen(dev->t10_wwn.model, INQUIRY_MODEL_LEN));
 	memcpy(&buf[32], dev->t10_wwn.revision,
 	       strnlen(dev->t10_wwn.revision, 4));
 	buf[4] = 31; /* Set additional length to 31 */
diff --git a/drivers/target/target_core_stat.c b/drivers/target/target_core_stat.c
index 4210cf625d84..9123c5137da5 100644
--- a/drivers/target/target_core_stat.c
+++ b/drivers/target/target_core_stat.c
@@ -261,10 +261,10 @@ static ssize_t target_stat_lu_prod_show(struct config_item *item, char *page)
 {
 	struct se_device *dev = to_stat_lu_dev(item);
 	int i;
-	char str[sizeof(dev->t10_wwn.model)+1];
+	char str[INQUIRY_MODEL_LEN+1];
 
 	/* scsiLuProductId */
-	for (i = 0; i < sizeof(dev->t10_wwn.model); i++)
+	for (i = 0; i < INQUIRY_MODEL_LEN; i++)
 		str[i] = ISPRINT(dev->t10_wwn.model[i]) ?
 			dev->t10_wwn.model[i] : ' ';
 	str[i] = '\0';
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index cb1f3f574e2a..cfc279686cf4 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -47,6 +47,7 @@
 #define INQUIRY_VPD_DEVICE_IDENTIFIER_LEN	254
 
 #define INQUIRY_VENDOR_LEN			8
+#define INQUIRY_MODEL_LEN			16
 
 /* Attempts before moving from SHORT to LONG */
 #define PYX_TRANSPORT_WINDOW_CLOSED_THRESHOLD	3
@@ -321,7 +322,7 @@ struct t10_wwn {
 	 * null terminator is always present.
 	 */
 	char vendor[INQUIRY_VENDOR_LEN + 1];
-	char model[16];
+	char model[INQUIRY_MODEL_LEN + 1];
 	char revision[4];
 	char unit_serial[INQUIRY_VPD_SERIAL_LEN];
 	spinlock_t t10_vpd_lock;
-- 
2.13.7