[PATCH 3.4 079/125] ses: fix additional element traversal bug

[lizf]

From: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>

3.4.113-rc1 review patch.  If anyone has any objections, please let me know.

------------------


commit 5e1033561da1152c57b97ee84371dba2b3d64c25 upstream.

KASAN found that our additional element processing scripts drop off
the end of the VPD page into unallocated space.  The reason is that
not every element has additional information but our traversal
routines think they do, leading to them expecting far more additional
information than is present.  Fix this by adding a gate to the
traversal routine so that it only processes elements that are expected
to have additional information (list is in SES-2 section 6.1.13.1:
Additional Element Status diagnostic page overview)

Reported-by: Pavel Tikhomirov <ptikhomirov@xxxxxxxxxxxxx>
Tested-by: Pavel Tikhomirov <ptikhomirov@xxxxxxxxxxxxx>
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
---
 drivers/scsi/ses.c        | 10 +++++++++-
 include/linux/enclosure.h |  4 ++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index b3051fe..3643bbf 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -454,7 +454,15 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
 			if (desc_ptr)
 				desc_ptr += len;
 
-			if (addl_desc_ptr)
+			if (addl_desc_ptr &&
+			    /* only find additional descriptions for specific devices */
+			    (type_ptr[0] == ENCLOSURE_COMPONENT_DEVICE ||
+			     type_ptr[0] == ENCLOSURE_COMPONENT_ARRAY_DEVICE ||
+			     type_ptr[0] == ENCLOSURE_COMPONENT_SAS_EXPANDER ||
+			     /* these elements are optional */
+			     type_ptr[0] == ENCLOSURE_COMPONENT_SCSI_TARGET_PORT ||
+			     type_ptr[0] == ENCLOSURE_COMPONENT_SCSI_INITIATOR_PORT ||
+			     type_ptr[0] == ENCLOSURE_COMPONENT_CONTROLLER_ELECTRONICS))
 				addl_desc_ptr += addl_desc_ptr[1] + 2;
 
 		}
diff --git a/include/linux/enclosure.h b/include/linux/enclosure.h
index 9a33c5f..f6c229e 100644
--- a/include/linux/enclosure.h
+++ b/include/linux/enclosure.h
@@ -29,7 +29,11 @@
 /* A few generic types ... taken from ses-2 */
 enum enclosure_component_type {
 	ENCLOSURE_COMPONENT_DEVICE = 0x01,
+	ENCLOSURE_COMPONENT_CONTROLLER_ELECTRONICS = 0x07,
+	ENCLOSURE_COMPONENT_SCSI_TARGET_PORT = 0x14,
+	ENCLOSURE_COMPONENT_SCSI_INITIATOR_PORT = 0x15,
 	ENCLOSURE_COMPONENT_ARRAY_DEVICE = 0x17,
+	ENCLOSURE_COMPONENT_SAS_EXPANDER = 0x18,
 };
 
 /* ses-2 common element status */
-- 
1.9.1