--[[
    This is an example of Lua-scripting within Proxmark3. This is a lua-side
    implementation of hf mf chk

    This code is licensed to you under the terms of the GNU GPL, version 2 or,
    at your option, any later version. See the LICENSE.txt file for the text of
    the license.

    Copyright (C) 2013 m h swende <martin at swende.se>
--]]
local cmds = require('commands')
local keylist = require('mfc_default_keys')
local lib14a = require('read14a')
local getopt = require('getopt')
local utils = require('utils')
local ansicolors  = require('ansicolors')

copyright = ''
author = "Holiman"
version = 'v1.0.2'
desc = ("This script implements Mifare check keys.\
It utilises a large list of default keys (currently %d keys).\
If you want to add more, just put them inside /lualibs/mfc_default_keys.lua\n"):format(#keylist)
example = [[
    1. script run hf_mf_keycheck
]]
usage = [[
script run hf_mf_keycheck [-p]
]]
arguments = [[
    -h             : this help
    -p             : print keys
]]

local PM3_SUCCESS = 0 -- needs to be refactored into own like pm3_cmd

local TIMEOUT = 10000 -- 10 seconds
---
-- This is only meant to be used when errors occur
local function oops(err)
    print('ERROR:', err)
    core.clearCommandBuffer()
    return nil, err
end
---
-- Usage help
local function help()
    print(copyright)
    print(author)
    print(version)
    print(desc)
    print(ansicolors.cyan..'Usage'..ansicolors.reset)
    print(usage)
    print(ansicolors.cyan..'Arguments'..ansicolors.reset)
    print(arguments)
    print(ansicolors.cyan..'Example usage'..ansicolors.reset)
    print(example)
end
--
-- waits for answer from pm3 device
local function checkCommand(response)
    if not response then
        print("Timeout while waiting for response. Increase TIMEOUT in hf_mf_keycheck.lua to wait longer")
        return nil, "Timeout while waiting for device to respond"
    end

    if response.Status == PM3_SUCCESS then
        --decode data array
        key = response.Data:sub(1, 12)
        found = tonumber(response.Data:sub(13,14))
        if found == 1 then
            return key
        end
    end
    return nil
end

local function checkBlock(blockno, testkeys, keytype)

    -- The command data is only 512 bytes,
    -- each key is 6 bytes,
    -- NG args inside dataarray is 4 bytes.  That give us (512-4)/6 or max 84 keys in one go.
    -- If there's more, we need to split it up
    local start, remaining = 1, #testkeys
    local maxchunk = math.floor((512-4)/6)
    local chunksize = remaining
    if remaining > maxchunk then chunksize = maxchunk end
    local n = chunksize

    while remaining > 0 do

        local d0 = ('%02X%02X00%02X'):format(keytype, blockno, chunksize)
        local d1 = table.concat(testkeys, "", start, n)

        core.clearCommandBuffer()

        print(("Testing block %d, keytype %d, with %d keys"):format(blockno, keytype, chunksize))

        local c = Command:newNG{cmd = cmds.CMD_HF_MIFARE_CHKKEYS, data = d0..d1}
        key, err = checkCommand(c:sendNG(false))

        if key then return key, blockno end

        start = start + chunksize
        remaining = remaining - chunksize

        if remaining < maxchunk then chunksize = remaining end
        n = n + chunksize
    end
    return nil
end
---
-- A function to display the results
local function display_results(keys)
    local sector, keyA, keyB, succA, succB
    print('')
    print('|---|----------------|---|----------------|---|')
    print('|sec|key A           |res|key B           |res|')
    print('|---|----------------|---|----------------|---|')

    for sector = 0, #keys do
        succA, succB, keyA, keyB = unpack(keys[sector])
        print(('|%03d|  %s  | %s |  %s  | %s |'):format(sector, keyA, succA, keyB, succB))
    end
    print('|---|----------------|---|----------------|---|')
end
---
-- A little helper to place an item first in the list
local function placeFirst(akey, list)
    akey = akey:lower()
    if list[1] == akey then
        -- Already at pole position
        return list
    end
    local result = {akey}
    --print(("Putting '%s' first"):format(akey))
    for i,v in ipairs(list) do
        if v ~= akey then
            result[#result+1] = v
        end
    end
    return result
end
--[[
The mifare Classic 1k card has 16 sectors of 4 data blocks each.
The first 32 sectors of a mifare Classic 4k card consists of 4 data blocks and the remaining
8 sectors consist of 16 data blocks.
--]]
local function get_blockno(s)

    local b, sector

    if type(s) == 'string' then
        sector = tonumber(s)
    else
        sector = s
    end

    if sector < 32 then
        b = sector * 4
    else
        b = 32 * 4 + (sector - 32) * 16
end
    return ('%02x'):format(b)
end
--
-- dumps all keys to file
local function dumptofile(uid, keys)
    if utils.confirm('Do you wish to save the keys to dumpfile?') then
        local filename = ('hf-mf-%s-key.bin'):format(uid);
        local destination = utils.input('Select a filename to store to', filename)
        local file = io.open(destination, 'wb')
        if file == nil then
            print('Could not write to file ', destination)
            return
        end

        local key_a = ''
        local key_b = ''

        --for sector,_ in pairs(keys) do
        for sector = 0, #keys do
            local succA, succB, keyA, keyB = unpack(keys[sector])
            key_a = key_a .. bin.pack('H', keyA);
            key_b = key_b .. bin.pack('H', keyB);
        end
        file:write(key_a)
        file:write(key_b)
        file:close()
    end
end
---
--
local function printkeys()
    for i=1, #keylist do
        print(i, keylist[i])
    end
    print ('Number of keys: '..#keylist)
end
---
--
local function perform_check(uid, numsectors)

    local keyType = 0 -- A=0, B=1

    -- empty list of found keys
    local keys = {}
    for i = 0, numsectors-1 do
        keys[i] = {0,0,'',''}
    end

    core.fast_push_mode(true)

    local start_time = os.time()

    for sector = 0, #keys do
        -- Check if user aborted
        if core.kbd_enter_pressed() then
            print('Aborted by user')
            break
        end

        local targetblock = tonumber(get_blockno(sector), 16)

        local succA, succB, keyA, keyB = unpack(keys[sector])

        local keyA = checkBlock(targetblock, keylist, 0)
        if keyA then succA = 1; keylist = placeFirst(keyA, keylist) end
        keyA = keyA or '------------'

        local keyB = checkBlock(targetblock, keylist, 1)
        if keyB then succB = 1; keylist = placeFirst(keyB, keylist) end
        keyB = keyB or '------------'

        keys[sector] = {succA, succB, keyA, keyB}
    end

    local end_time = os.time()
    print('')
    print('[+] hf_mf_keycheck - Checkkey execution time: '..os.difftime(end_time, start_time)..' sec')

    core.fast_push_mode(false)

    display_results(keys)

    -- save to dumpkeys.bin
    dumptofile(uid, keys)
end
--
-- shows tag information
local function taginfo(tag)

    local sectors = 16
    -- Show tag info
    print((' Found tag %s'):format(tag.name))

    if 0x18 == tag.sak then --NXP MIFARE Classic 4k | Plus 4k
        -- MIFARE Classic 4K offers 4096 bytes split into forty sectors,
        -- of which 32 are same size as in the 1K with eight more that are quadruple size sectors.
        sectors = 40
    elseif 0x08 == tag.sak then -- NXP MIFARE CLASSIC 1k | Plus 2k
        -- 1K offers 1024 bytes of data storage, split into 16 sector
        sectors = 16
    elseif 0x09 == tag.sak then -- NXP MIFARE Mini 0.3k
        -- MIFARE Classic mini offers 320 bytes split into five sectors.
        sectors = 5
    elseif  0x10 == tag.sak then-- "NXP MIFARE Plus 2k"
        sectors = 32
    else
        print("I don't know how many sectors there are on this type of card, defaulting to 16")
    end
    return sectors
end
---
-- The main entry point
local function main(args)

    -- Arguments for the script
    for o, a in getopt.getopt(args, 'hp') do
        if o == 'h' then return help() end
        if o == 'p' then return printkeys() end
    end
    -- identify tag
    tag, err = lib14a.read(false, true)
    if not tag then return oops(err) end

    local numSectors = 16

    -- detect sectors and print taginfo
    numsectors = taginfo(tag)

    perform_check(tag.uid, numsectors)
end

main( args)
