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target: Add sanity checks for DPO/FUA bit usage
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This patch adds a sbc_check_dpofua() function that performs sanity
checks for DPO/FUA command bits.

It introduces checks to fail when either bit is set, but the backend
device is not advertising support for them.

It also moves the existing cmd->se_cmd_flags |= SCF_FUA assignement
into the new helper function.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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Nicholas Bellinger committed Feb 14, 2015
1 parent afd73f1 commit fde9f50
Showing 1 changed file with 46 additions and 10 deletions.
56 changes: 46 additions & 10 deletions drivers/target/target_core_sbc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -692,6 +692,29 @@ sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
return TCM_NO_SENSE;
}

static int
sbc_check_dpofua(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb)
{
if (cdb[1] & 0x10) {
if (!dev->dev_attrib.emulate_dpo) {
pr_err("Got CDB: 0x%02x with DPO bit set, but device"
" does not advertise support for DPO\n", cdb[0]);
return -EINVAL;
}
}
if (cdb[1] & 0x8) {
if (!dev->dev_attrib.emulate_fua_write ||
!dev->dev_attrib.emulate_write_cache) {
pr_err("Got CDB: 0x%02x with FUA bit set, but device"
" does not advertise support for FUA write\n",
cdb[0]);
return -EINVAL;
}
cmd->se_cmd_flags |= SCF_FUA;
}
return 0;
}

sense_reason_t
sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
{
Expand All @@ -713,6 +736,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
sectors = transport_get_sectors_10(cdb);
cmd->t_task_lba = transport_lba_32(cdb);

if (sbc_check_dpofua(dev, cmd, cdb))
return TCM_INVALID_CDB_FIELD;

ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
if (ret)
return ret;
Expand All @@ -725,6 +751,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
sectors = transport_get_sectors_12(cdb);
cmd->t_task_lba = transport_lba_32(cdb);

if (sbc_check_dpofua(dev, cmd, cdb))
return TCM_INVALID_CDB_FIELD;

ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
if (ret)
return ret;
Expand All @@ -737,6 +766,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
sectors = transport_get_sectors_16(cdb);
cmd->t_task_lba = transport_lba_64(cdb);

if (sbc_check_dpofua(dev, cmd, cdb))
return TCM_INVALID_CDB_FIELD;

ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
if (ret)
return ret;
Expand All @@ -757,12 +789,13 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
sectors = transport_get_sectors_10(cdb);
cmd->t_task_lba = transport_lba_32(cdb);

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;

if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
cmd->execute_rw = ops->execute_rw;
cmd->execute_cmd = sbc_execute_rw;
Expand All @@ -771,12 +804,13 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
sectors = transport_get_sectors_12(cdb);
cmd->t_task_lba = transport_lba_32(cdb);

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;

if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
cmd->execute_rw = ops->execute_rw;
cmd->execute_cmd = sbc_execute_rw;
Expand All @@ -785,12 +819,13 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
sectors = transport_get_sectors_16(cdb);
cmd->t_task_lba = transport_lba_64(cdb);

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;

if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
cmd->execute_rw = ops->execute_rw;
cmd->execute_cmd = sbc_execute_rw;
Expand All @@ -801,6 +836,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
return TCM_INVALID_CDB_FIELD;
sectors = transport_get_sectors_10(cdb);

if (sbc_check_dpofua(dev, cmd, cdb))
return TCM_INVALID_CDB_FIELD;

cmd->t_task_lba = transport_lba_32(cdb);
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;

Expand All @@ -810,8 +848,6 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
cmd->execute_rw = ops->execute_rw;
cmd->execute_cmd = sbc_execute_rw;
cmd->transport_complete_callback = &xdreadwrite_callback;
if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
break;
case VARIABLE_LENGTH_CMD:
{
Expand All @@ -820,6 +856,8 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
case XDWRITEREAD_32:
sectors = transport_get_sectors_32(cdb);

if (sbc_check_dpofua(dev, cmd, cdb))
return TCM_INVALID_CDB_FIELD;
/*
* Use WRITE_32 and READ_32 opcodes for the emulated
* XDWRITE_READ_32 logic.
Expand All @@ -834,8 +872,6 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
cmd->execute_rw = ops->execute_rw;
cmd->execute_cmd = sbc_execute_rw;
cmd->transport_complete_callback = &xdreadwrite_callback;
if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
break;
case WRITE_SAME_32:
sectors = transport_get_sectors_32(cdb);
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