[PATCH 3.2 020/140] eeprom: at24: check at24_read/write arguments

[Ben Hutchings]

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

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

From: Heiner Kallweit <hkallweit1@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <brgl@xxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 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.