challenges/newbiecontest/prog/calcul/calcul.lua

#!/usr/bin/env lua

-- require ---------------------------------------------------------------------
local luasql = require "luasql.sqlite3" -- sqlite module
local http = require "socket.http" -- http module
local ltn12 = require("ltn12") -- ltn12 module used to convert a sink to a table

-- functions -------------------------------------------------------------------
-- Extract info about the cookie used for newbiecontest connection
function extract_cookie(db)

    -- cookie value
    cursor = db:execute("SELECT value FROM moz_cookies WHERE host LIKE\
    '%newbiecontest.org%' AND name LIKE '%SMFCookie%'")
    cookie_value = cursor:fetch(row)
    cursor:close()

    -- cookie name
    cursor = db:execute("SELECT name FROM moz_cookies WHERE host LIKE\
    '%newbiecontest.org%' AND name LIKE '%SMFCookie%'")
    cookie_name = cursor:fetch(row)
    cursor:close()

    return cookie_value, cookie_name

end

-- Extract number from a given url from newbiecontest
function extract_number(cookie_name, cookie_value, url)

    -- create the table
    local t = {}

    -- add the SMF cookie to the header
    local headers = {
        ["Cookie"] = cookie_name .. "=" .. cookie_value;
    }

    -- request
    r = http.request{url = url,
        headers = headers,
        sink = ltn12.sink.table(t) -- information goes to the table t
    }

    -- convert the answer to string
    string_r = table.concat(t)

    -- extract the number
    number = string.match(string_r, "%d+")

    return number

end

-- Do the sqrt(a) * b
function calcul(a, b)

    y = math.sqrt(a) * b

    return math.floor(y)

end

-- Give the response back to the server
function send_response(r, url)

    -- crate the table
    local t = {}

    -- concatenate the url
    url = url .. "?solution=" .. r

    -- add the SMF cookie to the header
    local headers = {
        ["Cookie"] = cookie_name .. "=" .. cookie_value;
    }

    -- send the reply
    r = http.request{url = url,
        headers = headers,
        sink = ltn12.sink.table(t)
    }

    print(table.concat(t)) -- print the token

    return 0

end

-- main -----------------------------------------------------------------------
if table.maxn(arg) < 4
    then
        print("Get. The. Fuck. Out")
        print("[i] Usage : ./calcul.lua file_db url_1 url_2 url_3")
        os.exit()
end

-- sqlite connection
env = luasql.sqlite3()
conn = env:connect(arg[1])

cookie_value, cookie_name = extract_cookie(conn)

a = extract_number(cookie_name, cookie_value, arg[2])
b = extract_number(cookie_name, cookie_value, arg[3])

r = calcul(a, b)

send_response(r, arg[4])

-- sqlite close
env:close()
conn:close()

print("Done.")