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[4.2.y-ckt,stable] Patch "ses: Fix problems with simple enclosures" has been added to the 4.2.y-ckt tree

Message ID 1452902184-26130-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Jan. 15, 2016, 11:56 p.m. UTC
This is a note to let you know that I have just added a patch titled

    ses: Fix problems with simple enclosures

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 28f9bf222d93dad9f6ba7f37a8561dec8732d835 Mon Sep 17 00:00:00 2001
From: James Bottomley <James.Bottomley@HansenPartnership.com>
Date: Tue, 8 Dec 2015 09:00:31 -0800
Subject: ses: Fix problems with simple enclosures

commit 3417c1b5cb1fdc10261dbed42b05cc93166a78fd upstream.

Simple enclosure implementations (mostly USB) are allowed to return only
page 8 to every diagnostic query.  That really confuses our
implementation because we assume the return is the page we asked for and
end up doing incorrect offsets based on bogus information leading to
accesses outside of allocated ranges.  Fix that by checking the page
code of the return and giving an error if it isn't the one we asked for.
This should fix reported bugs with USB storage by simply refusing to
attach to enclosures that behave like this.  It's also good defensive
practise now that we're starting to see more USB enclosures.

Reported-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/scsi/ses.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

--
1.9.1
diff mbox

Patch

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index dcb0d76..7d9cec5 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -84,6 +84,7 @@  static void init_device_slot_control(unsigned char *dest_desc,
 static int ses_recv_diag(struct scsi_device *sdev, int page_code,
 			 void *buf, int bufflen)
 {
+	int ret;
 	unsigned char cmd[] = {
 		RECEIVE_DIAGNOSTIC,
 		1,		/* Set PCV bit */
@@ -92,9 +93,26 @@  static int ses_recv_diag(struct scsi_device *sdev, int page_code,
 		bufflen & 0xff,
 		0
 	};
+	unsigned char recv_page_code;

-	return scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf, bufflen,
+	ret =  scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf, bufflen,
 				NULL, SES_TIMEOUT, SES_RETRIES, NULL);
+	if (unlikely(!ret))
+		return ret;
+
+	recv_page_code = ((unsigned char *)buf)[0];
+
+	if (likely(recv_page_code == page_code))
+		return ret;
+
+	/* successful diagnostic but wrong page code.  This happens to some
+	 * USB devices, just print a message and pretend there was an error */
+
+	sdev_printk(KERN_ERR, sdev,
+		    "Wrong diagnostic page; asked for %d got %u\n",
+		    page_code, recv_page_code);
+
+	return -EINVAL;
 }

 static int ses_send_diag(struct scsi_device *sdev, int page_code,