Messages in this thread | | | Date | Thu, 9 Jun 2022 10:55:57 +0200 (CEST) | From | Jiri Kosina <> | Subject | Re: [PATCH] HID: cp2112: prevent a buffer overflow in cp2112_xfer() |
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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,
-- Jiri Kosina SUSE Labs
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