[PATCH] scsi: target: core: check SR field in REPORT LUNS

[Dmitry Bogdanov <d.bogdanov@yadro.com>]

Now REPORT LUNS for software device servers always reports all luns
regardless of SELECT REPORT field.
Add handling of that field according to SPC-4:
* accept known values,
* reject unknown values.

Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com>
---
patch to 5.11/scsi-queue

 drivers/target/target_core_spc.c | 26 ++++++++++++++++++++++++++
 include/scsi/scsi_proto.h        | 10 ++++++++++
 2 files changed, 36 insertions(+)

diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index ca5579ebc81d..6af6272efce3 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -1210,10 +1210,12 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd)
 {
 	struct se_dev_entry *deve;
 	struct se_session *sess = cmd->se_sess;
+	unsigned char *cdb = cmd->t_task_cdb;
 	struct se_node_acl *nacl;
 	struct scsi_lun slun;
 	unsigned char *buf;
 	u32 lun_count = 0, offset = 8;
+	u8 sr = cdb[2];
 	__be32 len;
 
 	buf = transport_kmap_data_sg(cmd);
@@ -1230,6 +1232,27 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd)
 
 	nacl = sess->se_node_acl;
 
+	switch (sr) {
+	case SCSI_SELECT_WELLKNOWN:
+	case SCSI_SELECT_ADMINISTRATIVE:
+	case SCSI_SELECT_SUBSIDIARY:
+		/* report empty lun list */
+		goto out;
+	case SCSI_SELECT_TOP_LEVEL:
+		if (cmd->se_lun->unpacked_lun != 0)
+			goto out;
+		fallthrough;
+	case SCSI_SELECT_REGULAR:
+	case SCSI_SELECT_ALL_ACCESSIBLE:
+		break;
+	default:
+		pr_debug("TARGET_CORE[%s]: Invalid REPORT LUNS with unsupported "
+				 "SELECT REPORT %#x for 0x%08llx from %s\n",
+				 cmd->se_tfo->fabric_name, sr, cmd->se_lun->unpacked_lun,
+				 sess->se_node_acl->initiatorname);
+		return TCM_INVALID_CDB_FIELD;
+	}
+
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
 		/*
@@ -1252,6 +1275,8 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd)
 	 * See SPC3 r07, page 159.
 	 */
 done:
+	if ((sr != SCSI_SELECT_REGULAR) && (sr != SCSI_SELECT_ALL_ACCESSIBLE))
+		goto out;
 	/*
 	 * If no LUNs are accessible, report virtual LUN 0.
 	 */
@@ -1263,6 +1288,7 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd)
 		lun_count = 1;
 	}
 
+out:
 	if (buf) {
 		len = cpu_to_be32(lun_count * 8);
 		memcpy(buf, &len, min_t(int, sizeof len, cmd->data_length));
diff --git a/include/scsi/scsi_proto.h b/include/scsi/scsi_proto.h
index c36860111932..280169c75d85 100644
--- a/include/scsi/scsi_proto.h
+++ b/include/scsi/scsi_proto.h
@@ -341,4 +341,14 @@ enum zbc_zone_cond {
 	ZBC_ZONE_COND_OFFLINE		= 0xf,
 };
 
+/* Select Report fot REPORT LUNS */
+enum scsi_select_report {
+	SCSI_SELECT_REGULAR		= 0x0,
+	SCSI_SELECT_WELLKNOWN		= 0x1,
+	SCSI_SELECT_ALL_ACCESSIBLE	= 0x2,
+	SCSI_SELECT_ADMINISTRATIVE	= 0x10,
+	SCSI_SELECT_TOP_LEVEL		= 0x11,
+	SCSI_SELECT_SUBSIDIARY		= 0x12,
+};
+
 #endif /* _SCSI_PROTO_H_ */
-- 
2.25.1