Revert "target: Fix VERIFY and WRITE VERIFY command parsing"

This reverts commit 0e2eb7d12eaa8e391bf5615d4271bb87a649caaa

  Author: Bart Van Assche <bart.vanassche@sandisk.com>
  Date:   Thu Mar 30 10:12:39 2017 -0700

      target: Fix VERIFY and WRITE VERIFY command parsing

This patch broke existing behaviour for WRITE_VERIFY because
it dropped the original SCF_SCSI_DATA_CDB assignment for
bytchk = 0 so target_cmd_size_check() no longer rejected
this case, allowing an overflow case to trigger an OOPs
in iscsi-target.

Since the short term and long term fixes are still being
discussed, revert it for now since it's late in the merge
window and try again in v4.13-rc1.

Conflicts:
	drivers/target/target_core_sbc.c

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 10 insertions, 64 deletions

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index a0ad618f1b1a..4316f7b65fb7 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -831,60 +831,6 @@ sbc_check_dpofua(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb)
         return 0;
 }
 
-/**
- * sbc_parse_verify - parse VERIFY, VERIFY_16 and WRITE VERIFY commands
- * @cmd:     (in)  structure that describes the SCSI command to be parsed.
- * @sectors: (out) Number of logical blocks on the storage medium that will be
- *           affected by the SCSI command.
- * @bufflen: (out) Expected length of the SCSI Data-Out buffer.
- */
-static sense_reason_t sbc_parse_verify(struct se_cmd *cmd, int *sectors,
-                                       u32 *bufflen)
-{
-        struct se_device *dev = cmd->se_dev;
-        u8 *cdb = cmd->t_task_cdb;
-        u8 bytchk = (cdb[1] >> 1) & 3;
-        sense_reason_t ret;
-
-        switch (cdb[0]) {
-        case VERIFY:
-        case WRITE_VERIFY:
-                *sectors = transport_get_sectors_10(cdb);
-                cmd->t_task_lba = transport_lba_32(cdb);
-                break;
-        case VERIFY_16:
-        case WRITE_VERIFY_16:
-                *sectors = transport_get_sectors_16(cdb);
-                cmd->t_task_lba = transport_lba_64(cdb);
-                break;
-        default:
-                WARN_ON_ONCE(true);
-                return TCM_UNSUPPORTED_SCSI_OPCODE;
-        }
-
-        if (sbc_check_dpofua(dev, cmd, cdb))
-                return TCM_INVALID_CDB_FIELD;
-
-        ret = sbc_check_prot(dev, cmd, cdb, *sectors, true);
-        if (ret)
-                return ret;
-
-        switch (bytchk) {
-        case 0:
-                *bufflen = 0;
-                break;
-        case 1:
-                *bufflen = sbc_get_size(cmd, *sectors);
-                cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-                break;
-        default:
-                pr_err("Unsupported BYTCHK value %d for SCSI opcode %#x\n",
-                       bytchk, cdb[0]);
-                return TCM_INVALID_CDB_FIELD;
-        }
-        return TCM_NO_SENSE;
-}
-
 sense_reason_t
 sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
 {
@@ -952,6 +898,7 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
                 cmd->execute_cmd = sbc_execute_rw;
                 break;
         case WRITE_10:
+        case WRITE_VERIFY:
                 sectors = transport_get_sectors_10(cdb);
                 cmd->t_task_lba = transport_lba_32(cdb);
 
@@ -965,13 +912,6 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
                 cmd->execute_cmd = sbc_execute_rw;
                 break;
-        case WRITE_VERIFY:
-        case WRITE_VERIFY_16:
-                ret = sbc_parse_verify(cmd, &sectors, &size);
-                if (ret)
-                        return ret;
-                cmd->execute_cmd = sbc_execute_rw;
-                goto check_lba;
         case WRITE_12:
                 sectors = transport_get_sectors_12(cdb);
                 cmd->t_task_lba = transport_lba_32(cdb);
@@ -987,6 +927,7 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
                 cmd->execute_cmd = sbc_execute_rw;
                 break;
         case WRITE_16:
+        case WRITE_VERIFY_16:
                 sectors = transport_get_sectors_16(cdb);
                 cmd->t_task_lba = transport_lba_64(cdb);
 
@@ -1169,9 +1110,14 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
                 break;
         case VERIFY:
         case VERIFY_16:
-                ret = sbc_parse_verify(cmd, &sectors, &size);
-                if (ret)
-                        return ret;
+                size = 0;
+                if (cdb[0] == VERIFY) {
+                        sectors = transport_get_sectors_10(cdb);
+                        cmd->t_task_lba = transport_lba_32(cdb);
+                } else {
+                        sectors = transport_get_sectors_16(cdb);
+                        cmd->t_task_lba = transport_lba_64(cdb);
+                }
                 cmd->execute_cmd = sbc_emulate_noop;
                 goto check_lba;
         case REZERO_UNIT: