[PATCH v2 2/9] input: elan_i2c_smbus - fix corrupted stack

2018-04-09 Thread Benjamin Tissoires 
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:  # v4.4.x, v4.9.x, v4.14.x, v4.15.x, v4.16.x
Signed-off-by: Benjamin Tissoires 
---
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 = >dev;
int error;
u16 result;
-   u8 val[3];
+   u8 val[I2C_SMBUS_BLOCK_MAX] = {0};
 
/*
 * Due to the limitation of smbus protocol limiting
-- 
2.14.3

[PATCH v2 2/9] input: elan_i2c_smbus - fix corrupted stack

2018-04-09 Thread Benjamin Tissoires 
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:  # v4.4.x, v4.9.x, v4.14.x, v4.15.x, v4.16.x
Signed-off-by: Benjamin Tissoires 
---
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 = >dev;
int error;
u16 result;
-   u8 val[3];
+   u8 val[I2C_SMBUS_BLOCK_MAX] = {0};
 
/*
 * Due to the limitation of smbus protocol limiting
-- 
2.14.3