[3.16.y-ckt stable] Patch "ipr: Fix out-of-bounds null overwrite" has been added to the 3.16.y-ckt tree

[Luis Henriques]

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

    ipr: Fix out-of-bounds null overwrite

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt27.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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

>From 6cc63577dbcb5c955e23a95be8fa30a054f86bbc Mon Sep 17 00:00:00 2001
From: Insu Yun <wuninsu at gmail.com>
Date: Wed, 6 Jan 2016 12:44:01 -0500
Subject: ipr: Fix out-of-bounds null overwrite

commit d63c7dd5bcb9441af0526d370c43a65ca2c980d9 upstream.

Return value of snprintf is not bound by size value, 2nd argument.
(https://www.kernel.org/doc/htmldocs/kernel-api/API-snprintf.html).
Return value is number of printed chars, can be larger than 2nd
argument.  Therefore, it can write null byte out of bounds ofbuffer.
Since snprintf puts null, it does not need to put additional null byte.

Signed-off-by: Insu Yun <wuninsu at gmail.com>
Reviewed-by: Shane Seymour <shane.seymour at hpe.com>
Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
Cc: Ben Hutchings <ben at decadent.org.uk>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/scsi/ipr.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index d2c3fdcf90ba..824e66d7bf93 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -3984,13 +3984,12 @@ static ssize_t ipr_store_update_fw(struct device *dev,
 	struct ipr_sglist *sglist;
 	char fname[100];
 	char *src;
-	int len, result, dnld_size;
+	int result, dnld_size;

 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;

-	len = snprintf(fname, 99, "%s", buf);
-	fname[len-1] = '\0';
+	snprintf(fname, sizeof(fname), "%s", buf);

 	if (request_firmware(&fw_entry, fname, &ioa_cfg->pdev->dev)) {
 		dev_err(&ioa_cfg->pdev->dev, "Firmware file %s not found\n", fname);