[PATCH] [PATCH] staging:iio:light: V3 fix out of bounds reg_cache[] access
Jonathan Cameron
jic23 at cam.ac.uk
Fri Sep 9 08:53:05 UTC 2011
V3 is a straightforward forward port to teh current tree of V2.
Simple fix is to just not cache REG_TEST (offset 8).
Cache doesn't help REG_TEST anyway since we write all 8 bits exactly once
(at resume/init time).
Also fix an "off-by-one" allocation of reg_cache[] array size that
was in the original code before I touched it.
Reported-by: Dan Carpenter <error27 at gmail.com>
Signed-off-by: Grant Grundler <grundler at chromium.org>
Signed-off-by: Jonathan Cameron <jic23 at cam.ac.uk>
---
drivers/staging/iio/light/isl29018.c | 23 ++++++++++++++---------
1 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/drivers/staging/iio/light/isl29018.c b/drivers/staging/iio/light/isl29018.c
index f31e8c2..3e9a06c 100644
--- a/drivers/staging/iio/light/isl29018.c
+++ b/drivers/staging/iio/light/isl29018.c
@@ -51,7 +51,7 @@
#define ISL29018_REG_ADD_DATA_LSB 0x02
#define ISL29018_REG_ADD_DATA_MSB 0x03
-#define ISL29018_MAX_REGS ISL29018_REG_ADD_DATA_MSB
+#define ISL29018_MAX_REGS (ISL29018_REG_ADD_DATA_MSB+1)
#define ISL29018_REG_TEST 0x08
#define ISL29018_TEST_SHIFT 0
@@ -70,22 +70,27 @@ struct isl29018_chip {
static int isl29018_write_data(struct i2c_client *client, u8 reg,
u8 val, u8 mask, u8 shift)
{
- u8 regval;
- int ret = 0;
+ u8 regval = val;
+ int ret;
struct isl29018_chip *chip = iio_priv(i2c_get_clientdata(client));
- regval = chip->reg_cache[reg];
- regval &= ~mask;
- regval |= val << shift;
+ /* don't cache or mask REG_TEST */
+ if (reg < ISL29018_MAX_REGS) {
+ regval = chip->reg_cache[reg];
+ regval &= ~mask;
+ regval |= val << shift;
+ }
ret = i2c_smbus_write_byte_data(client, reg, regval);
if (ret) {
dev_err(&client->dev, "Write to device fails status %x\n", ret);
- return ret;
+ } else {
+ /* don't update cache on err */
+ if (reg < ISL29018_MAX_REGS)
+ chip->reg_cache[reg] = regval;
}
- chip->reg_cache[reg] = regval;
- return 0;
+ return ret;
}
static int isl29018_set_range(struct i2c_client *client, unsigned long range,
--
1.7.3.4
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