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Commit 974a4eb1 authored by Nicholas Bellinger's avatar Nicholas Bellinger Committed by Greg Kroah-Hartman
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target: Re-add check to reject control WRITEs with overflow data 



commit 4ff83daa0200affe1894bd33d17bac404e3d78d4 upstream.

During v4.3 when the overflow/underflow check was relaxed by
commit c72c5250:

  commit c72c5250
  Author: Roland Dreier <roland@purestorage.com>
  Date:   Wed Jul 22 15:08:18 2015 -0700

       target: allow underflow/overflow for PR OUT etc. commands

to allow underflow/overflow for Windows compliance + FCP, a
consequence was to allow control CDBs to process overflow
data for iscsi-target with immediate data as well.

As per Roland's original change, continue to allow underflow
cases for control CDBs to make Windows compliance + FCP happy,
but until overflow for control CDBs is supported tree-wide,
explicitly reject all control WRITEs with overflow following
pre v4.3.y logic.

Reported-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 96d7b43b

drivers/target/target_core_transport.c

+18 −5
Original line number Diff line number Diff line
@@ -1182,16 +1182,29 @@ target_cmd_size_check(struct se_cmd *cmd, unsigned int size) 
	if (cmd->unknown_data_length) {

		cmd->data_length = size;

	} else if (size != cmd->data_length) {

		pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"

		pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:"

			" %u does not match SCSI CDB Length: %u for SAM Opcode:"

			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),

				cmd->data_length, size, cmd->t_task_cdb[0]);



		if (cmd->data_direction == DMA_TO_DEVICE &&

		    cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {

			pr_err("Rejecting underflow/overflow WRITE data\n");

		if (cmd->data_direction == DMA_TO_DEVICE) {

			if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {

				pr_err_ratelimited("Rejecting underflow/overflow"

						   " for WRITE data CDB\n");

				return TCM_INVALID_CDB_FIELD;

			}

			/*

			 * Some fabric drivers like iscsi-target still expect to

			 * always reject overflow writes.  Reject this case until

			 * full fabric driver level support for overflow writes

			 * is introduced tree-wide.

			 */

			if (size > cmd->data_length) {

				pr_err_ratelimited("Rejecting overflow for"

						   " WRITE control CDB\n");

				return TCM_INVALID_CDB_FIELD;

			}

		}

		/*

		 * Reject READ_* or WRITE_* with overflow/underflow for

		 * type SCF_SCSI_DATA_CDB.