media: dvb-usb: dtv5100: fix out-of-bounds in dtv5100_i2c_msg()

media: dvb-usb: dtv5100: fix out-of-bounds in dtv5100_i2c_msg()

rlen value is a user-controlled value, but dtv5100_i2c_msg() does not
check the size of the rlen value. Therefore, if it is set to a value
larger than sizeof(st->data), an out-of-bounds vuln occurs for st->data.

Therefore, we need to add proper range checking to prevent this vuln.

Fixes: 60688d5e6e6e ("V4L/DVB (8735): dtv5100: replace dummy frontend by zl10353")
Cc: stable@vger.kernel.org
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>