linux-kernel - [PATCH 2/2] regmap: Add range check in _regmap_raw

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Date:	Thu, 19 Feb 2015 08:40:55 +0000
From:	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:	Mark Brown <broonie@...nel.org>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [PATCH 2/2] regmap: Add range check in _regmap_raw_write()

regmap_bulk_write() ends up using the path that invokes _regmap_raw_write(),
however _regmap_raw_write() never checks if the registers that are accessed
are actually within the accessible range. This results in kernel crashes when
trying to access registers beyond max_registers.

This patch just adds check before accessing the register range.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 drivers/base/regmap/regmap.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index d480e49..32ce7b3 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1202,16 +1202,14 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
 	void *buf;
 	int ret = -ENOTSUPP;
 	size_t len;
-	int i;
+	int i, count = val_len/map->format.val_bytes;
 
 	WARN_ON(!map->bus);
 
 	/* Check for unwritable registers before we start */
-	if (map->writeable_reg)
-		for (i = 0; i < val_len / map->format.val_bytes; i++)
-			if (!map->writeable_reg(map->dev,
-						reg + (i * map->reg_stride)))
-				return -EINVAL;
+	for (i = 0; i < count; i++)
+		if (!regmap_writeable(map, reg + (i * map->reg_stride)))
+			return -EINVAL;
 
 	if (!map->cache_bypass && map->format.parse_val) {
 		unsigned int ival;
-- 
1.9.1

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