From d9bcd462daf34aebb8de9ad7f76de0198bb5a0f0 Mon Sep 17 00:00:00 2001
From: Heiner Kallweit <hkallweit1@gmail.com>
Date: Fri, 24 Nov 2017 07:47:50 +0100
Subject: [PATCH] eeprom: at24: check at24_read/write arguments

So far we completely rely on the caller to provide valid arguments.
To be on the safe side perform an own sanity check.

Cc: stable@vger.kernel.org
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 drivers/misc/eeprom/at24.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 8ca6772b3baf3..305a7a464d091 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -569,6 +569,9 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
 	if (unlikely(!count))
 		return count;
 
+	if (off + count > at24->chip.byte_len)
+		return -EINVAL;
+
 	client = at24_translate_offset(at24, &off);
 
 	ret = pm_runtime_get_sync(&client->dev);
@@ -614,6 +617,9 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
 	if (unlikely(!count))
 		return -EINVAL;
 
+	if (off + count > at24->chip.byte_len)
+		return -EINVAL;
+
 	client = at24_translate_offset(at24, &off);
 
 	ret = pm_runtime_get_sync(&client->dev);