well at least if you consider being a very easy target for a
timing based password attack a problem...

Rather do the compare routine yourself so it has a constant
execution time (regardless where the first non-matching character is).

Do something like:

bit passwdchk()
{
  unsigned char i;
  unsigned char pattern = 0;
  for ( i=0; password[i]; i++ ) // assuming the known password is zero terminated
  {
    pattern |= (password[i] ^ passINP[i]);
  }
  return pattern == 0;
}
 

Note, there is no "if" keyword in the inner loop.