From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
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@xxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_transport.c | 21 +++++++++++++++++++++
1 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index d96d9aa..c33baff 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -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) {
--
1.7.2.5
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