[3.13.y-ckt stable] Patch "target: Add missing WRITE_SAME end-of-device sanity check" has been added to staging queue

[Kamal Mostafa]

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

    target: Add missing WRITE_SAME end-of-device sanity check

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt18.

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

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 773d04696ba64d31c96858596ca4116562778cf6 Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab at linux-iscsi.org>
Date: Fri, 13 Feb 2015 22:09:47 +0000
Subject: target: Add missing WRITE_SAME end-of-device sanity check

commit 8e575c50a171f2579e367a7f778f86477dfdaf49 upstream.

This patch adds a check to sbc_setup_write_same() to verify
the incoming WRITE_SAME LBA + number of blocks does not exceed
past the end-of-device.

Also check for potential LBA wrap-around as well.

Reported-by: Bart Van Assche <bart.vanassche at sandisk.com>
Cc: Martin Petersen <martin.petersen at oracle.com>
Cc: Christoph Hellwig <hch at lst.de>
Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/target/target_core_sbc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 6aae89d..3039bc4 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -260,6 +260,8 @@ static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
 static sense_reason_t
 sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *ops)
 {
+	struct se_device *dev = cmd->se_dev;
+	sector_t end_lba = dev->transport->get_blocks(dev) + 1;
 	unsigned int sectors = sbc_get_write_same_sectors(cmd);

 	if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
@@ -273,6 +275,16 @@ sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *o
 			sectors, cmd->se_dev->dev_attrib.max_write_same_len);
 		return TCM_INVALID_CDB_FIELD;
 	}
+	/*
+	 * Sanity check for LBA wrap and request past end of device.
+	 */
+	if (((cmd->t_task_lba + sectors) < cmd->t_task_lba) ||
+	    ((cmd->t_task_lba + sectors) > end_lba)) {
+		pr_err("WRITE_SAME exceeds last lba %llu (lba %llu, sectors %u)\n",
+		       (unsigned long long)end_lba, cmd->t_task_lba, sectors);
+		return TCM_ADDRESS_OUT_OF_RANGE;
+	}
+
 	/* We always have ANC_SUP == 0 so setting ANCHOR is always an error */
 	if (flags[0] & 0x10) {
 		pr_warn("WRITE SAME with ANCHOR not supported\n");
--
1.9.1