CGClear Admin

--CGClearServ v.0.0.7
--Credential Administration Tool
--Recommended Filename "CGCAdmin"
--Full Documentation unavailable.

--Begin Variable Config Block
local v = "v.0.0.7"
local mSide = "top" -- the side on which the modem has been placed.
local reqChan = 1 -- The channel the server will want to receive requests on.
local userChan = 2 -- the channel the server will send username information on
local passChan = 3 -- The channel the server uses to send password information
local credChan = 4 -- the channel the server uses to send credential information
local keyChan = 5 -- the channel that the administrator uses to send current tables to the server.
local downChan = 6 -- the channel that the server uses to talk to the client.
local saltChan = 7 -- the channel that the server uses to talk to the client.
local sodium = 16 -- the size (in bits) of the desired salts. Version max is 16.
local trust = "anything" -- the code the admin program expects from a trusted server.

--SHA-256 by GravityScore

--
--  Adaptation of the Secure Hashing Algorithm (SHA-244/256)
--  Found Here: http://lua-users.org/wiki/SecureHashAlgorithm
--
--  Using an adapted version of the bit library
--  Found Here: https://bitbucket.org/Boolsheet/bslf/src/1ee664885805/bit.lua
--

local MOD = 2^32
local MODM = MOD-1

local function memoize(f)
        local mt = {}
        local t = setmetatable({}, mt)
        function mt:__index(k)
                local v = f(k)
                t[k] = v
                return v
        end
        return t
end

local function make_bitop_uncached(t, m)
        local function bitop(a, b)
                local res,p = 0,1
                while a ~= 0 and b ~= 0 do
                        local am, bm = a % m, b % m
                        res = res + t[am][bm] * p
                        a = (a - am) / m
                        b = (b - bm) / m
                        p = p*m
                end
                res = res + (a + b) * p
                return res
        end
        return bitop
end

local function make_bitop(t)
        local op1 = make_bitop_uncached(t,2^1)
        local op2 = memoize(function(a) return memoize(function(b) return op1(a, b) end) end)
        return make_bitop_uncached(op2, 2 ^ (t.n or 1))
end

local bxor1 = make_bitop({[0] = {[0] = 0,[1] = 1}, [1] = {[0] = 1, [1] = 0}, n = 4})

local function bxor(a, b, c, ...)
        local z = nil
        if b then
                a = a % MOD
                b = b % MOD
                z = bxor1(a, b)
                if c then z = bxor(z, c, ...) end
                return z
        elseif a then return a % MOD
        else return 0 end
end

local function band(a, b, c, ...)
        local z
        if b then
                a = a % MOD
                b = b % MOD
                z = ((a + b) - bxor1(a,b)) / 2
                if c then z = bit32_band(z, c, ...) end
                return z
        elseif a then return a % MOD
        else return MODM end
end

local function bnot(x) return (-1 - x) % MOD end

local function rshift1(a, disp)
        if disp < 0 then return lshift(a,-disp) end
        return math.floor(a % 2 ^ 32 / 2 ^ disp)
end

local function rshift(x, disp)
        if disp > 31 or disp < -31 then return 0 end
        return rshift1(x % MOD, disp)
end

local function lshift(a, disp)
        if disp < 0 then return rshift(a,-disp) end
        return (a * 2 ^ disp) % 2 ^ 32
end

local function rrotate(x, disp)
    x = x % MOD
    disp = disp % 32
    local low = band(x, 2 ^ disp - 1)
    return rshift(x, disp) + lshift(low, 32 - disp)
end

local k = {
        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
        0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
        0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
        0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
        0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
        0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
        0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
        0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
        0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
        0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
        0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
        0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
        0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
        0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
        0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
        0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
}

local function str2hexa(s)
        return (string.gsub(s, ".", function(c) return string.format("%02x", string.byte(c)) end))
end

local function num2s(l, n)
        local s = ""
        for i = 1, n do
                local rem = l % 256
                s = string.char(rem) .. s
                l = (l - rem) / 256
        end
        return s
end

local function s232num(s, i)
        local n = 0
        for i = i, i + 3 do n = n*256 + string.byte(s, i) end
        return n
end

local function preproc(msg, len)
        local extra = 64 - ((len + 9) % 64)
        len = num2s(8 * len, 8)
        msg = msg .. "\128" .. string.rep("\0", extra) .. len
        assert(#msg % 64 == 0)
        return msg
end

local function initH256(H)
        H[1] = 0x6a09e667
        H[2] = 0xbb67ae85
        H[3] = 0x3c6ef372
        H[4] = 0xa54ff53a
        H[5] = 0x510e527f
        H[6] = 0x9b05688c
        H[7] = 0x1f83d9ab
        H[8] = 0x5be0cd19
        return H
end

local function digestblock(msg, i, H)
        local w = {}
        for j = 1, 16 do w[j] = s232num(msg, i + (j - 1)*4) end
        for j = 17, 64 do
                local v = w[j - 15]
                local s0 = bxor(rrotate(v, 7), rrotate(v, 18), rshift(v, 3))
                v = w[j - 2]
                w[j] = w[j - 16] + s0 + w[j - 7] + bxor(rrotate(v, 17), rrotate(v, 19), rshift(v, 10))
        end

        local a, b, c, d, e, f, g, h = H[1], H[2], H[3], H[4], H[5], H[6], H[7], H[8]
        for i = 1, 64 do
                local s0 = bxor(rrotate(a, 2), rrotate(a, 13), rrotate(a, 22))
                local maj = bxor(band(a, b), band(a, c), band(b, c))
                local t2 = s0 + maj
                local s1 = bxor(rrotate(e, 6), rrotate(e, 11), rrotate(e, 25))
                local ch = bxor (band(e, f), band(bnot(e), g))
                local t1 = h + s1 + ch + k[i] + w[i]
                h, g, f, e, d, c, b, a = g, f, e, d + t1, c, b, a, t1 + t2
        end

        H[1] = band(H[1] + a)
        H[2] = band(H[2] + b)
        H[3] = band(H[3] + c)
        H[4] = band(H[4] + d)
        H[5] = band(H[5] + e)
        H[6] = band(H[6] + f)
        H[7] = band(H[7] + g)
        H[8] = band(H[8] + h)
end

local function sha256(msg)
        msg = preproc(msg, #msg)
        local H = initH256({})
        for i = 1, #msg, 64 do digestblock(msg, i, H) end
        return str2hexa(num2s(H[1], 4) .. num2s(H[2], 4) .. num2s(H[3], 4) .. num2s(H[4], 4) ..
                num2s(H[5], 4) .. num2s(H[6], 4) .. num2s(H[7], 4) .. num2s(H[8], 4))
end

--Table/File Handling Protocols
local function load(name)
local file = fs.open(name, "r")
local data = file.readAll()
file.close()
return textutils.unserialize(data)
end

local function save(table, name)
local file = fs.open(name, "w")
file.write(textutils.serialize(table))
file.close()
end


--Initialization
--It is desirable that each individual program on this computer wrap the modem separately.
modem = peripheral.wrap(mSide)
modem.open(downChan)
modem.open(userChan)
modem.open(passChan)
modem.open(saltChan)
modem.open(credChan)
print("Requires your CGClear Admin Key:")
local input = read("*")
print("Valid Trust Key Input. Getting Database.")
modem.transmit(reqChan, downChan, sha256(input)) --Asks the server if this is a valid administrator
local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
if message == sha256(trust) then-- verifies that the server responding is the correct server.
    print("Server authentication complete.")
    modem.transmit(reqChan, downChan, "ping") -- tells the server to send the first packet.
    local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
    userHash = message -- turns the message into the UsersHash Table.
    print("Usernames Received.")
    modem.transmit(reqChan, downChan, "ping")
    local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
    passHash = message -- turns the message into a table, passHash.
    print("Passwords Received.")
    modem.transmit(reqChan, downChan, "ping")
    local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
    credHash = message -- turns the message into table credHash
    print("Clearance Data Received. Initializing Admin System.")
     salt = table.getn(userHash)     -- gets the number of users in the OLD hash
    tableSalt = {}                          -- Establishes the salt table which will be run GUID key to Salt.
        if salt == 1 then
            tableSalt[1] = {sha256(tostring(math.random(1,(2^sodium))))}
        else
            for s = 1, salt do                      -- Builds a whole new salt table for everyone to ensure security
                table.insert(tableSalt, s, sha256(tostring(math.random(1,(2^sodium)))))
            end
        end
            sleep(1)
            term.clear()
            term.setCursorPos(1,1)
            access = true
    --else -- input did not match the trust variable. This is currently broken and depends on some server rewrites
       -- print("Invalid Passcode")
       -- sleep(1)
       -- os.reboot() -- and consequently the player was not allowed to use this program
        end

while true do
if access == true then -- This creates the actual use environment.
                term.clear()
                term.setCursorPos(1, 1)
                print("Welcome to CGClear Administration " ..v)
                print("An Abbadon CompuSys Product.")
                print("--------")
                print("REM to remove users.")
                print("ADD to add a new user.")
                print("SAVE to safely close the program.")
                local cmd = read()
                if cmd == "REM" then -- This WHOLE sub governs the removal process.
                        print("Remove which user from the system?")
                        local user = read()
                        write("This will remove " ..user " from the system. Enter admin key to proceed.")
                        local input = read("*")
                        if input == trust then
                                for k, v in pairs do
                                    if v == sha256(user) then
                                        guid = k
                                    end
                                end
                                table.remove(passHash, guid)
                                table.remove(credHash, guid)
                                table.remove(saltHash, guid)
                        else
                                print("Absent or Invalid Key. Removal Cancelled.")
                                cmd = 0
                        end
                elseif cmd == "ADD" then --Okay, it wasn't a remove so it was an add...
                        print("Please enter the new user's username:")
                        local user = read()
                        print("Please enter the new user's password:")
                        local pass = read()
                        print("Please enter the new user's clearance level. (1 is Highest):")
                        local cred = read()
                        table.insert(userHash, user) -- adds the user to the main Users file.
                        --the for sub is trying to find the GUID of the new entry. And crashing.
                            for k,v in pairs(userHash) do
                                if v == user then
                                    guid = k
                                end
                            end
                        local salty = tostring(math.random(1, 2^sodium)) -- Gets salt for the tables.
                        table.insert(passHash, guid, sha256(pass .. salty)) -- concatenates password and salt and hashes them together.
                        table.insert(credHash, guid, sha256(cred))
                        table.insert(tableSalt, guid, salty)
                        print(user.." ".." "..pass.." "..cred.." successfully added")
                elseif cmd == "SAVE" then -- oh, he must have told me to exit.
                        print("Now exiting program.")
                        modem.transmit(keyChan, downChan, sha256(trust))--sends back all the tables necessary.
                        print("Authenticating to Server")
                        local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
                        print(message)
                        if message == sha256(trust) then
                            print("Authentic Server Detected.")
                                modem.transmit(userChan, keyChan, textutils.serialize(userHash))
                                print("Uploading Users.")
                                userHash = purged -- for shiggles.
                                local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
                                modem.transmit(passChan, keyChan, textutils.serialize(passHash))
                                print("Upload Passwords.")
                                passHash = purged -- for shiggles.
                                local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
                                modem.transmit(credChan, keyChan, textutils.serialize(userHash))
                                print("updating credentials.")
                                credHash = purged -- for shiggles.
                                local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
                                modem.transmit(saltChan, keyChan, textutils.serialize(tableSalt))
                                tableSalt = purged -- for shiggles.
                                print("Transmission Successful.")
                                --access = false
                        else
                                print ("Spoofing System Detected. Changes could not be Saved.")
                                sleep(5)
                        end
                else -- This should be expanded to give an actual error message.
                term.clear()
                term.setCursorPos(1,1)
                end
end
end