On Wed, 5 Dec 2012, Jean Delvare wrote: > > The previous memcpy implementation relied on the size advertized by the > > device. There were no guarantees that buf was big enough. > > > > Some gymnastic is also required with the +2/-2 to take into account > > the first 2 bytes of the returned buffer where the total returned > > length is supplied by the device. > > > > Signed-off-by: Benjamin Tissoires <[email protected]> > > --- > > drivers/hid/i2c-hid/i2c-hid.c | 16 ++++++++++++---- > > 1 file changed, 12 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c > > index c6630d4..ce01d59 100644 > > --- a/drivers/hid/i2c-hid/i2c-hid.c > > +++ b/drivers/hid/i2c-hid/i2c-hid.c > > @@ -502,23 +502,31 @@ static int i2c_hid_get_raw_report(struct hid_device > > *hid, > > { > > struct i2c_client *client = hid->driver_data; > > struct i2c_hid *ihid = i2c_get_clientdata(client); > > + size_t ret_count, ask_count; > > int ret; > > > > if (report_type == HID_OUTPUT_REPORT) > > return -EINVAL; > > > > - if (count > ihid->bufsize) > > - count = ihid->bufsize; > > + /* +2 bytes to include the size of the reply in the query buffer */ > > + ask_count = min(count + 2, (size_t)ihid->bufsize); > > > > ret = i2c_hid_get_report(client, > > report_type == HID_FEATURE_REPORT ? 0x03 : 0x01, > > - report_number, ihid->inbuf, count); > > + report_number, ihid->inbuf, ask_count); > > > > if (ret < 0) > > return ret; > > > > - count = ihid->inbuf[0] | (ihid->inbuf[1] << 8); > > + ret_count = ihid->inbuf[0] | (ihid->inbuf[1] << 8); > > > > + if (!ret_count) > > I'd make this (ret_count <= 2), as this would let you call memcpy with a > null or even negative length.
Good catch, it doesn't account for the 2 bytes needed for storing the reply size. I have fixed that and applied the patch, thanks everybody! -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
