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Commit 944981c7 authored by Nicholas Bellinger's avatar Nicholas Bellinger
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target: Add control CDB READ payload zero work-around 



This patch carries forward a work-around from tcm_loop to target
core code to explicitly clear control CDB READ paylods in order to
avoid bugs in scsi-generic user-space code for INQUIRY that do not
explicitly zero CDB payload memory.

(v2: Drop TARGET_SCF_MAP_CLEAR_MEM, and perform the explicit zero
     of READ memory for all target_submit_cmd_map_sgls users)

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 8f9f44f8

drivers/target/target_core_transport.c

+21 −0
Original line number Diff line number Diff line
@@ -1539,6 +1539,27 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess 
	if (sgl_count != 0) {

		BUG_ON(!sgl);



		/*

		 * A work-around for tcm_loop as some userspace code via

		 * scsi-generic do not memset their associated read buffers,

		 * so go ahead and do that here for type non-data CDBs.  Also

		 * note that this is currently guaranteed to be a single SGL

		 * for this case by target core in target_setup_cmd_from_cdb()

		 * -> transport_generic_cmd_sequencer().

		 */

		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&

		     se_cmd->data_direction == DMA_FROM_DEVICE) {

			unsigned char *buf = NULL;



			if (sgl)

				buf = kmap(sg_page(sgl)) + sgl->offset;



			if (buf) {

				memset(buf, 0, sgl->length);

				kunmap(sg_page(sgl));

			}

		}



		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,

				sgl_bidi, sgl_bidi_count);

		if (rc != 0) {