endless loop in utf8_len

[danncy]

function validatorlib.utf8_len(s) local c, j=0, 1 while j <= #s do local cb = str_byte(s, j) if cb >= 0 and cb <= 127 then j = j + 1 elseif cb >= 192 and cb <= 223 then j = j + 2 elseif cb >= 224 and cb <= 239 then j = j + 3 elseif cb >= 240 and cb <= 247 then j = j + 4 end c = c + 1 end return c end

input "%ff", after urldecode ，str_byte(s,j), when cb > 247，#s = 1, j = 1 , will cause endless loop

[Gerrard-YNWA]

@danncy Thanks for the report, @membphis I think it's indeed a serious problem, I will send a fix later.