V2 Fix out-of-bounds reference to reg_cache[]
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@xxxxxxxxx>
Signed-off-by: Grant Grundler <grundler@xxxxxxxxxxxx>
----
Thanks again to Dan Carpenter for spotting the out-of-bounds array reference.
V2 preserves "don't touch reg_cache[] on error" behavior.
diff --git a/drivers/staging/iio/light/isl29018.c b/drivers/staging/iio/light/isl29018.c
index 0f97734..b24d28c 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
@@ -71,22 +71,27 @@ 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 = 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) {
+ 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,
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