patch "nvmem: mxs-ocotp: fix buffer overflow in read" added to char-misc-linus

patch "nvmem: mxs-ocotp: fix buffer overflow in read" added to char-misc-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    nvmem: mxs-ocotp: fix buffer overflow in read

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From d1306eb675ad7a9a760b6b8e8e189824b8db89e7 Mon Sep 17 00:00:00 2001
From: Stanislav Meduna <stano@meduna.org>
Date: Mon, 2 May 2016 16:05:11 +0100
Subject: nvmem: mxs-ocotp: fix buffer overflow in read

This patch fixes the issue where the mxs_ocotp_read is reading
the ocotp in reg_size steps but decrements the remaining size
by 1. The number of iterations is thus four times higher,
overwriting the area behind the output buffer.

Fixes: c01e9a11ab6f ("nvmem: add driver for ocotp in i.MX23 and i.MX28")
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Stanislav Meduna <stano@meduna.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/nvmem/mxs-ocotp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvmem/mxs-ocotp.c b/drivers/nvmem/mxs-ocotp.c
index 8ba19bba3156..2bb3c5799ac4 100644
--- a/drivers/nvmem/mxs-ocotp.c
+++ b/drivers/nvmem/mxs-ocotp.c
@@ -94,7 +94,7 @@ static int mxs_ocotp_read(void *context, const void *reg, size_t reg_size,
 	if (ret)
 		goto close_banks;
 
-	while (val_size) {
+	while (val_size >= reg_size) {
 		if ((offset < OCOTP_DATA_OFFSET) || (offset % 16)) {
 			/* fill up non-data register */
 			*buf = 0;
@@ -103,7 +103,7 @@ static int mxs_ocotp_read(void *context, const void *reg, size_t reg_size,
 		}
 
 		buf++;
-		val_size--;
+		val_size -= reg_size;
 		offset += reg_size;
 	}
 
-- 
2.8.2