From: Stanislav Meduna <stano@meduna.org>
Date: Mon, 2 May 2016 15:05:11 +0000 (+0100)
Subject: nvmem: mxs-ocotp: fix buffer overflow in read
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d1306eb675ad7a9a760b6b8e8e189824b8db89e7;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

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>
---

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;
 	}