[4.2.y-ckt stable] Patch "ses: fix additional element traversal bug" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ses: fix additional element traversal bug

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 05bdc6e5118fb03b403f77b2f38738e5167a452d Mon Sep 17 00:00:00 2001
From: James Bottomley <James.Bottomley at HansenPartnership.com>
Date: Fri, 11 Dec 2015 09:16:38 -0800
Subject: ses: fix additional element traversal bug

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 at virtuozzo.com>
Tested-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
Signed-off-by: James Bottomley <James.Bottomley at HansenPartnership.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 7d9cec5..044d064 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -559,7 +559,15 @@ 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 7be22da..a4cf57c 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