New ICs (like the one on the Lenovo T480s) answer to ETP_SMBUS_IAP_VERSION_CMD 4 bytes instead of 3. This corrupts the stack as i2c_smbus_read_block_data() uses the values returned by the i2c device to know how many data it need to return.

i2c_smbus_read_block_data() can read up to 32 bytes (I2C_SMBUS_BLOCK_MAX) and there is no safeguard on how many bytes are provided in the return value. Ensure we always have enough space for any future firmware. Also 0-initialize the values to prevent any access to uninitialized memory.

Cc: stable@vger.kernel.org # v4.4.x, v4.9.x, v4.14.x, v4.15.x, v4.16.x Signed-off-by: Benjamin Tissoires benjamin.tissoires@redhat.com --- no changes in v2

drivers/input/mouse/elan_i2c_smbus.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/input/mouse/elan_i2c_smbus.c b/drivers/input/mouse/elan_i2c_smbus.c index 29f99529b187..cfcb32559925 100644 --- a/drivers/input/mouse/elan_i2c_smbus.c +++ b/drivers/input/mouse/elan_i2c_smbus.c @@ -130,7 +130,7 @@ static int elan_smbus_get_baseline_data(struct i2c_client *client, bool max_baseline, u8 *value) { int error; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

error = i2c_smbus_read_block_data(client, max_baseline ? @@ -149,7 +149,7 @@ static int elan_smbus_get_version(struct i2c_client *client, bool iap, u8 *version) { int error; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

error = i2c_smbus_read_block_data(client, iap ? ETP_SMBUS_IAP_VERSION_CMD : @@ -170,7 +170,7 @@ static int elan_smbus_get_sm_version(struct i2c_client *client, u8 *clickpad) { int error; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

error = i2c_smbus_read_block_data(client, ETP_SMBUS_SM_VERSION_CMD, val); @@ -188,7 +188,7 @@ static int elan_smbus_get_sm_version(struct i2c_client *client, static int elan_smbus_get_product_id(struct i2c_client *client, u16 *id) { int error; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

error = i2c_smbus_read_block_data(client, ETP_SMBUS_UNIQUEID_CMD, val); @@ -205,7 +205,7 @@ static int elan_smbus_get_checksum(struct i2c_client *client, bool iap, u16 *csum) { int error; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

error = i2c_smbus_read_block_data(client, iap ? ETP_SMBUS_FW_CHECKSUM_CMD : @@ -226,7 +226,7 @@ static int elan_smbus_get_max(struct i2c_client *client, { int ret; int error; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

ret = i2c_smbus_read_block_data(client, ETP_SMBUS_RANGE_CMD, val); if (ret != 3) { @@ -246,7 +246,7 @@ static int elan_smbus_get_resolution(struct i2c_client *client, { int ret; int error; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

ret = i2c_smbus_read_block_data(client, ETP_SMBUS_RESOLUTION_CMD, val); if (ret != 3) { @@ -267,7 +267,7 @@ static int elan_smbus_get_num_traces(struct i2c_client *client, { int ret; int error; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

ret = i2c_smbus_read_block_data(client, ETP_SMBUS_XY_TRACENUM_CMD, val); if (ret != 3) { @@ -294,7 +294,7 @@ static int elan_smbus_iap_get_mode(struct i2c_client *client, { int error; u16 constant; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

error = i2c_smbus_read_block_data(client, ETP_SMBUS_IAP_CTRL_CMD, val); if (error < 0) { @@ -345,7 +345,7 @@ static int elan_smbus_prepare_fw_update(struct i2c_client *client) int len; int error; enum tp_mode mode; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0}; u8 cmd[4] = {0x0F, 0x78, 0x00, 0x06}; u16 password;

@@ -419,7 +419,7 @@ static int elan_smbus_write_fw_block(struct i2c_client *client, struct device *dev = &client->dev; int error; u16 result; - u8 val[3]; + u8 val[I2C_SMBUS_BLOCK_MAX] = {0};

/* * Due to the limitation of smbus protocol limiting