@@ -175,6 +175,8 @@ static int adm1266_gpio_get(struct gpio_chip *chip, unsigned int offset)
ret = i2c_smbus_read_block_data(data->client, pmbus_cmd, read_buf);
if (ret < 0)
return ret;
+ if (ret < 2)
+ return -EIO;
pins_status = read_buf[0] + (read_buf[1] << 8);
if (offset < ADM1266_GPIO_NR)
@@ -195,6 +197,8 @@ static int adm1266_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask
ret = i2c_smbus_read_block_data(data->client, ADM1266_GPIO_STATUS, read_buf);
if (ret < 0)
return ret;
+ if (ret < 2)
+ return -EIO;
status = read_buf[0] + (read_buf[1] << 8);
@@ -207,6 +211,8 @@ static int adm1266_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask
ret = i2c_smbus_read_block_data(data->client, ADM1266_PDIO_STATUS, read_buf);
if (ret < 0)
return ret;
+ if (ret < 2)
+ return -EIO;
status = read_buf[0] + (read_buf[1] << 8);
adm1266_gpio_get() and adm1266_gpio_get_multiple() both compose the pin-status word as pins_status = read_buf[0] + (read_buf[1] << 8); right after i2c_smbus_read_block_data(), guarding only against an error return. A well-behaved device returns 2 bytes for GPIO_STATUS/PDIO_STATUS, but the helper happily reports a 0- or 1-byte response too. If the device returns 0 bytes, both read_buf slots are uninitialized stack memory; if it returns 1 byte, read_buf[1] is. The composed value then flows through set_bit() into the caller's *bits in adm1266_gpio_get_multiple(), or into the return value of adm1266_gpio_get(), and ends up in userspace via gpiolib (sysfs and the char-dev ioctls). That leaks a few bits of kernel stack per request on any device whose firmware glitch, bus error, or hostile slave produces a short block-read response. Add the missing length check to both call sites and surface a short response as -EIO. Fixes: d98dfad35c38 ("hwmon: (pmbus/adm1266) Add support for GPIOs") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain <abdurrahman@nexthop.ai> Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> --- drivers/hwmon/pmbus/adm1266.c | 6 ++++++ 1 file changed, 6 insertions(+)