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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Heiner Kallweit" <hkallweit1@gmail.com>,
        "Bartosz Golaszewski" <brgl@bgdev.pl>
Date:   Wed, 28 Feb 2018 15:20:18 +0000
Message-ID: <lsq.1519831218.489823704@decadent.org.uk>
Subject: [PATCH 3.16 032/254] eeprom: at24: check at24_read/write arguments
In-Reply-To: <lsq.1519831217.271785318@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Heiner Kallweit <hkallweit1@gmail.com>

commit d9bcd462daf34aebb8de9ad7f76de0198bb5a0f0 upstream.

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

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

--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -274,6 +274,9 @@ static ssize_t at24_read(struct at24_dat
 	if (unlikely(!count))
 		return count;
 
+	if (off + count > at24->chip.byte_len)
+		return -EINVAL;
+
 	/*
 	 * Read data from chip, protecting against concurrent updates
 	 * from this host, but not from other I2C masters.
@@ -396,6 +399,9 @@ static ssize_t at24_write(struct at24_da
 	if (unlikely(!count))
 		return count;
 
+	if (off + count > at24->chip.byte_len)
+		return -EINVAL;
+
 	/*
 	 * Write data to chip, protecting against concurrent updates
 	 * from this host, but not from other I2C masters.