2022-09-14 08:36:26

by ChiYuan Huang

Subject: [PATCH] mfd: mt6360: add bound check in regmap read/write function

From: ChiYuan Huang <[email protected]>

Fix the potential risk for null pointer if bank index is over the maximimum.

Refer to the discussion list for the experiment result on mt6370.
https://lore.kernel.org/all/[email protected]/
If not to check the bound, there is the same issue on mt6360.

Fixes: 3b0850440a06c (mfd: mt6360: Merge different sub-devices I2C read/write)
Cc: [email protected]
Signed-off-by: ChiYuan Huang <[email protected]>
---
drivers/mfd/mt6360-core.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/mfd/mt6360-core.c b/drivers/mfd/mt6360-core.c
index 6eaa677..d375333 100644
--- a/drivers/mfd/mt6360-core.c
+++ b/drivers/mfd/mt6360-core.c
@@ -410,6 +410,9 @@ static int mt6360_regmap_read(void *context, const void *reg, size_t reg_size,
u8 crc;
int ret;

+ if (bank >= MT6360_SLAVE_MAX)
+ return -EINVAL;
+
if (bank == MT6360_SLAVE_PMIC || bank == MT6360_SLAVE_LDO) {
crc_needed = true;
ret = mt6360_xlate_pmicldo_addr(&reg_addr, val_size);
@@ -460,6 +463,9 @@ static int mt6360_regmap_write(void *context, const void *val, size_t val_size)
int write_size = val_size - MT6360_REGMAP_REG_BYTE_SIZE;
int ret;

+ if (bank >= MT6360_SLAVE_MAX)
+ return -EINVAL;
+
if (bank == MT6360_SLAVE_PMIC || bank == MT6360_SLAVE_LDO) {
crc_needed = true;
ret = mt6360_xlate_pmicldo_addr(&reg_addr, val_size - MT6360_REGMAP_REG_BYTE_SIZE);
--
2.7.4

2022-09-28 10:38:11

by Lee Jones

Subject: Re: [PATCH] mfd: mt6360: add bound check in regmap read/write function

On Wed, 14 Sep 2022, cy_huang wrote:

> From: ChiYuan Huang <[email protected]>
>
> Fix the potential risk for null pointer if bank index is over the maximimum.
>
> Refer to the discussion list for the experiment result on mt6370.
> https://lore.kernel.org/all/[email protected]/
> If not to check the bound, there is the same issue on mt6360.
>
> Fixes: 3b0850440a06c (mfd: mt6360: Merge different sub-devices I2C read/write)
> Cc: [email protected]
> Signed-off-by: ChiYuan Huang <[email protected]>
> ---
> drivers/mfd/mt6360-core.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/mfd/mt6360-core.c b/drivers/mfd/mt6360-core.c
> index 6eaa677..d375333 100644
> --- a/drivers/mfd/mt6360-core.c
> +++ b/drivers/mfd/mt6360-core.c
> @@ -410,6 +410,9 @@ static int mt6360_regmap_read(void *context, const void *reg, size_t reg_size,
> u8 crc;
> int ret;
>
> + if (bank >= MT6360_SLAVE_MAX)
> + return -EINVAL;
> +

It's too late to check bank's value here, we have already used it to
index into an array by this point. Please fix that.

> if (bank == MT6360_SLAVE_PMIC || bank == MT6360_SLAVE_LDO) {
> crc_needed = true;
> ret = mt6360_xlate_pmicldo_addr(&reg_addr, val_size);
> @@ -460,6 +463,9 @@ static int mt6360_regmap_write(void *context, const void *val, size_t val_size)
> int write_size = val_size - MT6360_REGMAP_REG_BYTE_SIZE;
> int ret;
>
> + if (bank >= MT6360_SLAVE_MAX)
> + return -EINVAL;
> +
> if (bank == MT6360_SLAVE_PMIC || bank == MT6360_SLAVE_LDO) {
> crc_needed = true;
> ret = mt6360_xlate_pmicldo_addr(&reg_addr, val_size - MT6360_REGMAP_REG_BYTE_SIZE);

--
Lee Jones [李琼斯]