| Message ID | 20220608122609.70861-1-harshit.m.mogalapalli@oracle.com |
|---|---|
| State | Accepted |
| Commit | 381583845d19cb4bd21c8193449385f3fefa9caf |
| Headers | show |
| Series | HID: cp2112: prevent a buffer overflow in cp2112_xfer() | expand |
On Wed, 8 Jun 2022, Harshit Mogalapalli wrote: > Smatch warnings: > drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy() > 'data->block[1]' too small (33 vs 255) > drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy() 'buf' too > small (64 vs 255) > > The 'read_length' variable is provided by 'data->block[0]' which comes > from user and it(read_length) can take a value between 0-255. Add an > upper bound to 'read_length' variable to prevent a buffer overflow in > memcpy(). > > Fixes: 542134c0375b ("HID: cp2112: Fix I2C_BLOCK_DATA transactions") > Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com> > --- > drivers/hid/hid-cp2112.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c > index ece147d1a278..1e16b0fa310d 100644 > --- a/drivers/hid/hid-cp2112.c > +++ b/drivers/hid/hid-cp2112.c > @@ -790,6 +790,11 @@ static int cp2112_xfer(struct i2c_adapter *adap, u16 addr, > data->word = le16_to_cpup((__le16 *)buf); > break; > case I2C_SMBUS_I2C_BLOCK_DATA: > + if (read_length > I2C_SMBUS_BLOCK_MAX) { > + ret = -EINVAL; > + goto power_normal; > + } > + > memcpy(data->block + 1, buf, read_length); > break; Good catch, now applied. Thanks,
diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c index ece147d1a278..1e16b0fa310d 100644 --- a/drivers/hid/hid-cp2112.c +++ b/drivers/hid/hid-cp2112.c @@ -790,6 +790,11 @@ static int cp2112_xfer(struct i2c_adapter *adap, u16 addr, data->word = le16_to_cpup((__le16 *)buf); break; case I2C_SMBUS_I2C_BLOCK_DATA: + if (read_length > I2C_SMBUS_BLOCK_MAX) { + ret = -EINVAL; + goto power_normal; + } + memcpy(data->block + 1, buf, read_length); break; case I2C_SMBUS_BLOCK_DATA:
Smatch warnings: drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy() 'data->block[1]' too small (33 vs 255) drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy() 'buf' too small (64 vs 255) The 'read_length' variable is provided by 'data->block[0]' which comes from user and it(read_length) can take a value between 0-255. Add an upper bound to 'read_length' variable to prevent a buffer overflow in memcpy(). Fixes: 542134c0375b ("HID: cp2112: Fix I2C_BLOCK_DATA transactions") Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com> --- drivers/hid/hid-cp2112.c | 5 +++++ 1 file changed, 5 insertions(+)