scsi: target: iscsi: Add support for extended CDB AHS

Variable length SCSI commands are transferred over iSCSI via two CDB
buffers - in Basic Header Segment and in Additional Header Segment (AHS).
Since AHS is not supported yet, a target reads just BHS (48 byte) from TCP
and treats the remaining octets as a next new iSCSI PDU that causes
protocol errors.

Add support for the Extended CDB AHS type.

Link: https://lore.kernel.org/r/20220718152555.17084-2-d.bogdanov@yadro.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index bfb7170..baf4da7 100644 (file)
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -1004,8 +1004,10 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
                          unsigned char *buf)
 {
        int data_direction, payload_length;
+       struct iscsi_ecdb_ahdr *ecdb_ahdr;
        struct iscsi_scsi_req *hdr;
        int iscsi_task_attr;
+       unsigned char *cdb;
        int sam_task_attr;
 
        atomic_long_inc(&conn->sess->cmd_pdus);
@@ -1106,6 +1108,27 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
                                             ISCSI_REASON_BOOKMARK_INVALID, buf);
        }
 
+       cdb = hdr->cdb;
+
+       if (hdr->hlength) {
+               ecdb_ahdr = (struct iscsi_ecdb_ahdr *) (hdr + 1);
+               if (ecdb_ahdr->ahstype != ISCSI_AHSTYPE_CDB) {
+                       pr_err("Additional Header Segment type %d not supported!\n",
+                              ecdb_ahdr->ahstype);
+                       return iscsit_add_reject_cmd(cmd,
+                               ISCSI_REASON_CMD_NOT_SUPPORTED, buf);
+               }
+
+               cdb = kmalloc(be16_to_cpu(ecdb_ahdr->ahslength) + 15,
+                             GFP_KERNEL);
+               if (cdb == NULL)
+                       return iscsit_add_reject_cmd(cmd,
+                               ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);
+               memcpy(cdb, hdr->cdb, ISCSI_CDB_SIZE);
+               memcpy(cdb + ISCSI_CDB_SIZE, ecdb_ahdr->ecdb,
+                      be16_to_cpu(ecdb_ahdr->ahslength) - 1);
+       }
+
        data_direction = (hdr->flags & ISCSI_FLAG_CMD_WRITE) ? DMA_TO_DEVICE :
                         (hdr->flags & ISCSI_FLAG_CMD_READ) ? DMA_FROM_DEVICE :
                          DMA_NONE;
@@ -1153,9 +1176,12 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
                struct iscsi_datain_req *dr;
 
                dr = iscsit_allocate_datain_req();
-               if (!dr)
+               if (!dr) {
+                       if (cdb != hdr->cdb)
+                               kfree(cdb);
                        return iscsit_add_reject_cmd(cmd,
                                        ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);
+               }
 
                iscsit_attach_datain_req(cmd, dr);
        }
@@ -1176,9 +1202,12 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
        target_get_sess_cmd(&cmd->se_cmd, true);
 
        cmd->se_cmd.tag = (__force u32)cmd->init_task_tag;
-       cmd->sense_reason = target_cmd_init_cdb(&cmd->se_cmd, hdr->cdb,
+       cmd->sense_reason = target_cmd_init_cdb(&cmd->se_cmd, cdb,
                                                GFP_KERNEL);
 
+       if (cdb != hdr->cdb)
+               kfree(cdb);
+
        if (cmd->sense_reason) {
                if (cmd->sense_reason == TCM_OUT_OF_RESOURCES) {
                        return iscsit_add_reject_cmd(cmd,
@@ -4036,8 +4065,9 @@ static bool iscsi_target_check_conn_state(struct iscsit_conn *conn)
 static void iscsit_get_rx_pdu(struct iscsit_conn *conn)
 {
        int ret;
-       u8 *buffer, opcode;
+       u8 *buffer, *tmp_buf, opcode;
        u32 checksum = 0, digest = 0;
+       struct iscsi_hdr *hdr;
        struct kvec iov;
 
        buffer = kcalloc(ISCSI_HDR_LEN, sizeof(*buffer), GFP_KERNEL);
@@ -4062,6 +4092,25 @@ static void iscsit_get_rx_pdu(struct iscsit_conn *conn)
                        break;
                }
 
+               hdr = (struct iscsi_hdr *) buffer;
+               if (hdr->hlength) {
+                       iov.iov_len = hdr->hlength * 4;
+                       tmp_buf = krealloc(buffer,
+                                         ISCSI_HDR_LEN + iov.iov_len,
+                                         GFP_KERNEL);
+                       if (!tmp_buf)
+                               break;
+
+                       buffer = tmp_buf;
+                       iov.iov_base = &buffer[ISCSI_HDR_LEN];
+
+                       ret = rx_data(conn, &iov, 1, iov.iov_len);
+                       if (ret != iov.iov_len) {
+                               iscsit_rx_thread_wait_for_tcp(conn);
+                               break;
+                       }
+               }
+
                if (conn->conn_ops->HeaderDigest) {
                        iov.iov_base    = &digest;
                        iov.iov_len     = ISCSI_CRC_LEN;