[SCSI] libiscsi, iscsi_tcp, iscsi_iser: check that burst lengths are valid.

iSCSI RFC states that the first burst length must be smaller than the
max burst length. We currently assume targets will be good, but that may
not be the case, so this patch adds a check.

This patch also moves the unsol data out offset to the lib so the LLDs
do not have to track it.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

3 files changed, 24 insertions, 32 deletions

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 058f094f945a..a97a3a4e99eb 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -1264,19 +1264,6 @@ iscsi_solicit_data_cont(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
                             r2t->data_count);
 }
 
-static void
-iscsi_unsolicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
-{
-        struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-        struct iscsi_data_task *dtask;
-
-        dtask = tcp_ctask->dtask = &tcp_ctask->unsol_dtask;
-        iscsi_prep_unsolicit_data_pdu(ctask, &dtask->hdr,
-                                      tcp_ctask->r2t_data_count);
-        iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)&dtask->hdr,
-                           sizeof(struct iscsi_hdr));
-}
-
 /**
  * iscsi_tcp_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
  * @conn: iscsi connection
@@ -1326,14 +1313,11 @@ iscsi_tcp_cmd_init(struct iscsi_cmd_task *ctask)
                 if (ctask->unsol_count)
                         tcp_ctask->xmstate |= XMSTATE_UNS_HDR |
                                                 XMSTATE_UNS_INIT;
-                tcp_ctask->r2t_data_count = ctask->total_length -
-                                    ctask->imm_count -
-                                    ctask->unsol_count;
 
-                debug_scsi("cmd [itt 0x%x total %d imm %d imm_data %d "
-                           "r2t_data %d]\n",
+                debug_scsi("cmd [itt 0x%x total %d imm_data %d "
+                           "unsol count %d, unsol offset %d]\n",
                            ctask->itt, ctask->total_length, ctask->imm_count,
-                           ctask->unsol_count, tcp_ctask->r2t_data_count);
+                           ctask->unsol_count, ctask->unsol_offset);
         } else
                 tcp_ctask->xmstate = XMSTATE_R_HDR;
 
@@ -1531,8 +1515,10 @@ handle_xmstate_uns_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
 
         tcp_ctask->xmstate |= XMSTATE_UNS_DATA;
         if (tcp_ctask->xmstate & XMSTATE_UNS_INIT) {
-                iscsi_unsolicit_data_init(conn, ctask);
-                dtask = tcp_ctask->dtask;
+                dtask = tcp_ctask->dtask = &tcp_ctask->unsol_dtask;
+                iscsi_prep_unsolicit_data_pdu(ctask, &dtask->hdr);
+                iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)&dtask->hdr,
+                                   sizeof(struct iscsi_hdr));
                 if (conn->hdrdgst_en)
                         iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
                                         (u8*)dtask->hdrext);
@@ -1720,7 +1706,6 @@ data_out_done:
          * Done with this R2T. Check if there are more
          * outstanding R2Ts ready to be processed.
          */
-        BUG_ON(tcp_ctask->r2t_data_count - r2t->data_length < 0);
         if (conn->datadgst_en) {
                 rc = iscsi_digest_final_send(conn, ctask, &dtask->digestbuf,
                                             &dtask->digest, 1);
@@ -1732,7 +1717,6 @@ data_out_done:
                 debug_tcp("r2t done dout digest 0x%x\n", dtask->digest);
         }
 
-        tcp_ctask->r2t_data_count -= r2t->data_length;
         tcp_ctask->r2t = NULL;
         spin_lock_bh(&session->lock);
         __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
diff --git a/drivers/scsi/iscsi_tcp.h b/drivers/scsi/iscsi_tcp.h
index 6a4ee704e46e..aace8f70dfd7 100644
--- a/drivers/scsi/iscsi_tcp.h
+++ b/drivers/scsi/iscsi_tcp.h
@@ -157,7 +157,6 @@ struct iscsi_tcp_cmd_task {
         struct scatterlist      *bad_sg;                /* assert statement */
         int                     sg_count;               /* SG's to process  */
         uint32_t                exp_r2tsn;
-        int                     r2t_data_count;         /* R2T Data-Out bytes */
         int                     data_offset;
         struct iscsi_r2t_info   *r2t;                   /* in progress R2T    */
         struct iscsi_queue      r2tpool;
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 5884cd26d53a..a7c6e70f4ef8 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -68,8 +68,7 @@ iscsi_check_assign_cmdsn(struct iscsi_session *session, struct iscsi_nopin *hdr)
 EXPORT_SYMBOL_GPL(iscsi_check_assign_cmdsn);
 
 void iscsi_prep_unsolicit_data_pdu(struct iscsi_cmd_task *ctask,
-                                   struct iscsi_data *hdr,
-                                   int transport_data_cnt)
+                                   struct iscsi_data *hdr)
 {
         struct iscsi_conn *conn = ctask->conn;
 
@@ -82,14 +81,12 @@ void iscsi_prep_unsolicit_data_pdu(struct iscsi_cmd_task *ctask,
 
         hdr->itt = ctask->hdr->itt;
         hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
-
-        hdr->offset = cpu_to_be32(ctask->total_length -
-                                  transport_data_cnt -
-                                  ctask->unsol_count);
+        hdr->offset = cpu_to_be32(ctask->unsol_offset);
 
         if (ctask->unsol_count > conn->max_xmit_dlength) {
                 hton24(hdr->dlength, conn->max_xmit_dlength);
                 ctask->data_count = conn->max_xmit_dlength;
+                ctask->unsol_offset += ctask->data_count;
                 hdr->flags = 0;
         } else {
                 hton24(hdr->dlength, ctask->unsol_count);
@@ -125,6 +122,7 @@ static void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
         memcpy(hdr->cdb, sc->cmnd, sc->cmd_len);
         memset(&hdr->cdb[sc->cmd_len], 0, MAX_COMMAND_SIZE - sc->cmd_len);
 
+        ctask->data_count = 0;
         if (sc->sc_data_direction == DMA_TO_DEVICE) {
                 hdr->flags |= ISCSI_FLAG_CMD_WRITE;
                 /*
@@ -143,6 +141,7 @@ static void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
                  */
                 ctask->imm_count = 0;
                 ctask->unsol_count = 0;
+                ctask->unsol_offset = 0;
                 ctask->unsol_datasn = 0;
 
                 if (session->imm_data_en) {
@@ -156,9 +155,12 @@ static void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
                 } else
                         zero_data(ctask->hdr->dlength);
 
-                if (!session->initial_r2t_en)
+                if (!session->initial_r2t_en) {
                         ctask->unsol_count = min(session->first_burst,
                                 ctask->total_length) - ctask->imm_count;
+                        ctask->unsol_offset = ctask->imm_count;
+                }
+
                 if (!ctask->unsol_count)
                         /* No unsolicit Data-Out's */
                         ctask->hdr->flags |= ISCSI_FLAG_CMD_FINAL;
@@ -1520,11 +1522,18 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
         struct iscsi_conn *conn = cls_conn->dd_data;
         struct iscsi_session *session = conn->session;
 
-        if (session == NULL) {
+        if (!session) {
                 printk(KERN_ERR "iscsi: can't start unbound connection\n");
                 return -EPERM;
         }
 
+        if (session->first_burst > session->max_burst) {
+                printk("iscsi: invalid burst lengths: "
+                       "first_burst %d max_burst %d\n",
+                       session->first_burst, session->max_burst);
+                return -EINVAL;
+        }
+
         spin_lock_bh(&session->lock);
         conn->c_stage = ISCSI_CONN_STARTED;
         session->state = ISCSI_STATE_LOGGED_IN;