Commit 50fc7b61 authored by Ben Hutchings's avatar Ben Hutchings Committed by Dmitry Torokhov
Browse files

Input: elan_i2c_smbus - fix more potential stack buffer overflows

Commit 40f7090b

 ("Input: elan_i2c_smbus - fix corrupted stack")
fixed most of the functions using i2c_smbus_read_block_data() to
allocate a buffer with the maximum block size.  However three
functions were left unchanged:

* In elan_smbus_initialize(), increase the buffer size in the same
  way.
* In elan_smbus_calibrate_result(), the buffer is provided by the
  caller (calibrate_store()), so introduce a bounce buffer.  Also
  name the result buffer size.
* In elan_smbus_get_report(), the buffer is provided by the caller
  but happens to be the right length.  Add a compile-time assertion
  to ensure this remains the case.

Cc: <stable@vger.kernel.org> # 3.19+
Signed-off-by: default avatarBen Hutchings <ben.hutchings@codethink.co.uk>
Reviewed-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 8938fc7b
......@@ -27,6 +27,8 @@
#define ETP_DISABLE_POWER 0x0001
#define ETP_PRESSURE_OFFSET 25
#define ETP_CALIBRATE_MAX_LEN 3
/* IAP Firmware handling */
#define ETP_PRODUCT_ID_FORMAT_STRING "%d.0"
#define ETP_FW_NAME "elan_i2c_" ETP_PRODUCT_ID_FORMAT_STRING ".bin"
......
......@@ -613,7 +613,7 @@ static ssize_t calibrate_store(struct device *dev,
int tries = 20;
int retval;
int error;
u8 val[3];
u8 val[ETP_CALIBRATE_MAX_LEN];
retval = mutex_lock_interruptible(&data->sysfs_mutex);
if (retval)
......
......@@ -56,7 +56,7 @@
static int elan_smbus_initialize(struct i2c_client *client)
{
u8 check[ETP_SMBUS_HELLOPACKET_LEN] = { 0x55, 0x55, 0x55, 0x55, 0x55 };
u8 values[ETP_SMBUS_HELLOPACKET_LEN] = { 0, 0, 0, 0, 0 };
u8 values[I2C_SMBUS_BLOCK_MAX] = {0};
int len, error;
/* Get hello packet */
......@@ -117,12 +117,16 @@ static int elan_smbus_calibrate(struct i2c_client *client)
static int elan_smbus_calibrate_result(struct i2c_client *client, u8 *val)
{
int error;
u8 buf[I2C_SMBUS_BLOCK_MAX] = {0};
BUILD_BUG_ON(ETP_CALIBRATE_MAX_LEN > sizeof(buf));
error = i2c_smbus_read_block_data(client,
ETP_SMBUS_CALIBRATE_QUERY, val);
ETP_SMBUS_CALIBRATE_QUERY, buf);
if (error < 0)
return error;
memcpy(val, buf, ETP_CALIBRATE_MAX_LEN);
return 0;
}
......@@ -472,6 +476,8 @@ static int elan_smbus_get_report(struct i2c_client *client, u8 *report)
{
int len;
BUILD_BUG_ON(I2C_SMBUS_BLOCK_MAX > ETP_SMBUS_REPORT_LEN);
len = i2c_smbus_read_block_data(client,
ETP_SMBUS_PACKET_QUERY,
&report[ETP_SMBUS_REPORT_OFFSET]);
......
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