proxmark3/client/luascripts/Legic_clone.lua

--[[
    script to create a clone-dump with new crc
  Author: mosci
   my Fork: https://github.com/icsom/proxmark3.git
    Upstream: https://github.com/Proxmark/proxmark3.git

    1. read tag-dump, xor byte 22..end with byte 0x05 of the inputfile
    2. write to outfile
    3. set byte 0x05 to newcrc
    4. until byte 0x21 plain like in inputfile
    5. from 0x22..end xored with newcrc
    6. calculate new crc on each segment (needs to know the new MCD & MSN0..2)

    simplest usage:
    read a valid legic tag with 'hf legic reader'
    save the dump with 'hf legic save orig.hex'
  place your 'empty' tag on the reader and run 'script run Legic_clone -i orig.hex -w'
  you will see some output like:
        read 1024 bytes from legic_dumps/j_0000.hex

        place your empty tag onto the PM3 to read and display the MCD & MSN0..2
        the values will be shown below
         confirm when ready [y/n] ?y
        #db# setting up legic card
        #db# MIM 256 card found, reading card ...
        #db# Card read, use 'hf legic decode' or
        #db# 'data hexsamples 8' to view results
        0b ad c0 de  <- !! here you'll see the MCD & MSN of your empty tag, which has to be typed in manually as seen below !!
        type in  MCD as 2-digit value - e.g.: 00 (default: 79 )
         > 0b
        type in MSN0 as 2-digit value - e.g.: 01 (default: 28 )
         > ad
        type in MSN1 as 2-digit value - e.g.: 02 (default: d1 )
         > c0
        type in MSN2 as 2-digit value - e.g.: 03 (default: 43 )
         > de
        MCD:0b, MSN:ad c0 de, MCC:79 <- this crc is calculated from the MCD & MSN and must match the one on yout empty tag

        wrote 1024 bytes to myLegicClone.hex
        enter number of bytes to write? (default: 86 )

        loaded 1024 samples
        #db# setting up legic card
        #db# MIM 256 card found, writing 0x00 - 0x01 ...
        #db# write successful
        ...
        #db# setting up legic card
        #db# MIM 256 card found, writing 0x56 - 0x01 ...
        #db# write successful
        proxmark3>

    the default value (number of bytes to write) is calculated over all valid segments and should be ok - just hit enter, wait until write has finished
    and your clone should be ready (except there has to be a additional KGH-CRC to be calculated - which credentials are unknown until yet)

    the '-w' switch will only work with my fork - it needs the binary legic_crc8 which is not part of the proxmark3-master-branch
    also the ability to write DCF is not possible with the proxmark3-master-branch
    but creating dumpfile-clone files will be possible (without valid segment-crc - this has to done manually with)


    (example)   Legic-Prime Layout with 'Kaba Group Header'
      +----+----+----+----+----+----+----+----+
  0x00|MCD |MSN0|MSN1|MSN2|MCC | 60 | ea | 9f |
      +----+----+----+----+----+----+----+----+
  0x08| ff | 00 | 00 | 00 | 11 |Bck0|Bck1|Bck2|
      +----+----+----+----+----+----+----+----+
  0x10|Bck3|Bck4|Bck5|BCC | 00 | 00 |Seg0|Seg1|
      +----+----+----+----+----+----+----+----+
  0x18|Seg2|Seg3|SegC|Stp0|Stp1|Stp2|Stp3|UID0|
      +----+----+----+----+----+----+----+----+
  0x20|UID1|UID2|kghC|
      +----+----+----+

        MCD=     ManufacturerID           (1 Byte)
        MSN0..2= ManufactureSerialNumber  (3 Byte)
        MCC=     CRC                      (1 Byte) calculated over MCD,MSN0..2
        DCF=     DecrementalField         (2 Byte) 'credential' (enduser-Tag) seems to have always DCF-low=0x60 DCF-high=0xea
        Bck0..5= Backup                   (6 Byte) Bck0 'dirty-flag', Bck1..5 SegmentHeader-Backup
        BCC=     BackupCRC                (1 Byte) CRC calculated over Bck1..5
        Seg0..3= SegmentHeader            (on MIM 4 Byte )
        SegC=    SegmentCRC               (1 Byte) calculated over MCD,MSN0..2,Seg0..3
        Stp0..n= Stamp0...                (variable length) length = Segment-Len - UserData - 1
        UID0..n= UserDater                (variable length - with KGH hex 0x00-0x63 / dec 0-99) length = Segment-Len - WRP - WRC - 1
        kghC=    KabaGroupHeader          (1 Byte + addr 0x0c must be 0x11)
    as seen on this example: addr 0x05..0x08 & 0x0c must have been set to this values - otherwise kghCRC will not be created by a official reader (not accepted)
--]]

copyright = ''
author = 'Mosci'
version = 'v1.0.1'
desc = [[
This is a script which creates a clone-dump of a dump from a Legic Prime Tag (MIM256 or MIM1024)
(created with 'hf legic save my_dump.hex')
]]
example = [[
    script run legic_clone -i my_dump.hex -o my_clone.hex -c f8
    script run legic_clone -i my_dump.hex -d -s
]]
usage = [[
script run legic_clone -h -i <file> -o <file> -c <crc> -d -s -w

required arguments:
    -i <input file>     (file to read data from)

optional arguments :
    -h                  - Help text
    -o <output file>    - requires option -c to be given
    -c <new-tag crc>    - requires option -o to be given
    -d                  - Display content of found Segments
    -s                  - Display summary at the end
    -w                  - write directly to Tag - a file myLegicClone.hex wille be generated also

    e.g.:
    hint: using the CRC '00' will result in a plain dump ( -c 00 )
]]
local utils = require('utils')
local getopt = require('getopt')
local bxor = bit32.bxor

-- we need always 2 digits
local function prepend_zero(s)
    if (string.len(s) == 1) then
        return '0' .. s
    else
        if (string.len(s) == 0) then
            return '00'
        else
            return s
        end
    end
end

---
-- 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('Example usage')
    print(example)
    print(usage)
end

-- Check availability of file
local function file_check(file_name)
    local file_found = io.open(file_name, "r")
    if not file_found then
        file_found = false
    else
        file_found = true
    end
    return file_found
end

--- xor-wrapper
-- xor all from addr 0x22 (start counting from 1 => 23)
local function xorme(hex, xor, index)
    if ( index >= 23 ) then
        return ('%02x'):format(bxor( tonumber(hex,16) , tonumber(xor,16) ))
    else
        return hex
    end
end

-- read input-file into array
local function getInputBytes(infile)
    local line
    local bytes = {}

    local fhi,err = io.open(infile)
    if err then print("OOps ... faild to read from file ".. infile); return false; end

    while true do
        line = fhi:read()
        if line == nil then break end

        for byte in line:gmatch("%w+") do
            table.insert(bytes, byte)
        end
    end

    fhi:close()

    print("\nread ".. #bytes .." bytes from ".. infile)
    return bytes
end

-- write to file
local function writeOutputBytes(bytes, outfile)
    local line
    local bcnt = 0
    local fho,err = io.open(outfile,"w")
    if err then print("OOps ... faild to open output-file ".. outfile); return false; end

    for i = 1, #bytes do
        if (bcnt == 0) then
            line = bytes[i]
        elseif (bcnt <= 7) then
            line = line.." "..bytes[i]
        end
        if (bcnt == 7) then
            -- write line to new file
            fho:write(line.."\n")
            -- reset counter & line
            bcnt = -1
            line = ""
        end
        bcnt = bcnt + 1
    end
    fho:close()
    print("\nwrote ".. #bytes .." bytes to " .. outfile)
    return true
end

-- xore certain bytes
local function xorBytes(inBytes, crc)
    local bytes = {}
    for index = 1, #inBytes do
        bytes[index] = xorme(inBytes[index], crc, index)
    end
    if (#inBytes == #bytes) then
        -- replace crc
        bytes[5] = string.sub(crc,-2)
        return bytes
    else
        print("error: byte-count missmatch")
        return false
    end
end

-- get raw segment-data
function getSegmentData(bytes, start, index)
    local raw, len, valid, last, wrp, wrc, rd, crc
    local segment = {}
    segment[0] = bytes[start]..' '..bytes[start+1]..' '..bytes[start+2]..' '..bytes[start+3]
    -- flag = high nibble of byte 1
    segment[1] = string.sub(bytes[start+1],0,1)

    -- valid = bit 6 of byte 1
    segment[2] = tonumber(bit32.extract('0x'..bytes[start+1],6,1),16)

    -- last = bit 7 of byte 1
    segment[3] = tonumber(bit32.extract('0x'..bytes[start+1],7,1),16)

    -- len = (byte 0)+(bit0-3 of byte 1)
  segment[4] = tonumber(('%03x'):format(tonumber(bit32.extract('0x'..bytes[start+1],0,3),16)..tonumber(bytes[start],16)),16)

    -- wrp (write proteted) = byte 2
    segment[5] = tonumber(bytes[start+2])

    -- wrc (write control) - bit 4-6 of byte 3
    segment[6] = tonumber(bit32.extract('0x'..bytes[start+3],4,3),16)

    -- rd (read disabled) - bit 7 of byte 3
    segment[7] = tonumber(bit32.extract('0x'..bytes[start+3],7,1),16)

    -- crc byte 4
    segment[8] = bytes[start+4]

    -- segment index
    segment[9] = index

    -- # crc-byte
    segment[10] = start+4
  return segment
end

--- Kaba Group Header
-- checks if a segment does have a kghCRC
-- returns boolean false if no kgh has being detected or the kghCRC if a kgh was detected
function CheckKgh(bytes, segStart, segEnd)
    if (bytes[8]=='9f' and bytes[9]=='ff' and bytes[13]=='11') then
        local i
        local data = {}
        segStart = tonumber(segStart, 10)
        segEnd = tonumber(segEnd, 10)
        local dataLen = segEnd-segStart-5
        --- gather creadentials for verify
        local WRP = bytes[(segStart+2)]
        local WRC = ("%02x"):format(tonumber(bit32.extract("0x"..bytes[segStart+3],4,3),16))
        local RD = ("%02x"):format(tonumber(bit32.extract("0x"..bytes[segStart+3],7,1),16))
        local XX = "00"
        cmd = bytes[1]..bytes[2]..bytes[3]..bytes[4]..WRP..WRC..RD..XX
        for i = (segStart+5), (segStart+5+dataLen-2) do
            cmd = cmd..bytes[i]
        end
        local KGH = ("%02x"):format(utils.Crc8Legic(cmd))
        if (KGH == bytes[segEnd-1]) then
            return KGH
        else
            return false
        end
    else
        return false
    end
end

-- get only the addresses of segemnt-crc's and the length of bytes
function getSegmentCrcBytes(bytes)
    local start = 23
    local index = 0
    local crcbytes = {}
    repeat
        seg = getSegmentData(bytes,start,index)
        crcbytes[index] = seg[10]
        start = start + seg[4]
        index = index + 1
    until (seg[3] == 1 or tonumber(seg[9]) == 126 )
    crcbytes[index] = start
    return crcbytes
end

-- print segment-data (hf legic decode like)
function displaySegments(bytes)
    --display segment header(s)
    start = 23
    index = '00'

    --repeat until last-flag ist set to 1 or segment-index has reached 126
    repeat
        wrc = ''
        wrp = ''
        pld = ''
        Seg = getSegmentData(bytes, start, index)
        KGH = CheckKgh(bytes, start, (start+tonumber(Seg[4],10)))
        printSegment(Seg)

        -- wrc
        if (Seg[6] > 0) then
            print("WRC protected area:")
            -- length of wrc = wrc
            for i=1, Seg[6] do
                -- starts at (segment-start + segment-header + segment-crc)-1
                wrc = wrc..bytes[(start+4+1+i)-1]..' '
            end
            print(wrc)
        elseif (Seg[5] > 0) then
            print("Remaining write protected area:")
            -- length of wrp = (wrp-wrc)
            for i=1, (Seg[5]-Seg[6]) do
                -- starts at (segment-start + segment-header + segment-crc + wrc)-1
                wrp = wrp..bytes[(start+4+1+Seg[6]+i)-1]..' '
            end
            print(wrp)
        end

        -- payload
        print("Remaining segment payload:")
        --length of payload = segment-len - segment-header - segment-crc - wrp -wrc
        for i=1, (Seg[4]-4-1-Seg[5]-Seg[6]) do
            -- starts at (segment-start + segment-header + segment-crc + segment-wrp + segemnt-wrc)-1
            pld = pld..bytes[(start+4+1+Seg[5]+Seg[6]+i)-1]..' '
        end
        print(pld)
        if (KGH) then
            print("'Kaba Group Header' detected")
        end
        start = start+Seg[4]
        index = prepend_zero(tonumber(Seg[9])+1)

    until (Seg[3] == 1 or tonumber(Seg[9]) == 126 )
end

-- print Segment values
function printSegment(SegmentData)
    res = "\nSegment "..SegmentData[9]..": "
    res = res.. "raw header="..SegmentData[0]..", "
    res = res.. "flag="..SegmentData[1].." (valid="..SegmentData[2].." last="..SegmentData[3].."), "
    res = res.. "len="..("%04d"):format(SegmentData[4])..", "
    res = res.. "WRP="..prepend_zero(SegmentData[5])..", "
    res = res.. "WRC="..prepend_zero(SegmentData[6])..", "
    res = res.. "RD="..SegmentData[7]..", "
    res = res.. "crc="..SegmentData[8]
    print(res)
end

-- write clone-data to tag
function writeToTag(plainBytes)
    local SegCrcs = {}
    if(utils.confirm("\nplace your empty tag onto the PM3 to read and display the MCD & MSN0..2\nthe values will be shown below\n confirm when ready") == false) then
    return
  end

    -- gather MCD & MSN from new Tag - this must be enterd manually
    cmd = 'hf legic read 0x00 0x04'
    core.console(cmd)
    print("\nthese are the MCD MSN0 MSN1 MSN2 from the Tag that has being read:")
    cmd = 'data hexsamples 4'
    core.console(cmd)
    print("^^ use this values as input for the following answers (one 2-digit-value per question/answer):")
    -- enter MCD & MSN (in hex)
    MCD  = utils.input("type in  MCD as 2-digit value - e.g.: 00", plainBytes[1])
    MSN0 = utils.input("type in MSN0 as 2-digit value - e.g.: 01", plainBytes[2])
    MSN1 = utils.input("type in MSN1 as 2-digit value - e.g.: 02", plainBytes[3])
    MSN2 = utils.input("type in MSN2 as 2-digit value - e.g.: 03", plainBytes[4])

    -- calculate crc8 over MCD & MSN
    cmd = MCD..MSN0..MSN1..MSN2
    MCC = ("%02x"):format(utils.Crc8Legic(cmd))
    print("MCD:"..MCD..", MSN:"..MSN0.." "..MSN1.." "..MSN2..", MCC:"..MCC)

    -- calculate new Segment-CRC for each valid segment
    SegCrcs = getSegmentCrcBytes(plainBytes)
    for i=0, (#SegCrcs-1) do
    -- SegCrcs[i]-4 = address of first byte of segmentHeader (low byte segment-length)
    segLen = tonumber(("%1x"):format(tonumber(bit32.extract("0x"..plainBytes[(SegCrcs[i]-3)],0,3),16))..("%02x"):format(tonumber(plainBytes[SegCrcs[i]-4],16)),16)
    segStart = (SegCrcs[i]-4)
    segEnd = (SegCrcs[i]-4+segLen)
    KGH = CheckKgh(plainBytes,segStart,segEnd)
    if (KGH) then
      print("'Kaba Group Header' detected - re-calculate...")
    end
        cmd = MCD..MSN0..MSN1..MSN2..plainBytes[SegCrcs[i]-4]..plainBytes[SegCrcs[i]-3]..plainBytes[SegCrcs[i]-2]..plainBytes[SegCrcs[i]-1]
        plainBytes[SegCrcs[i]] = ("%02x"):format(utils.Crc8Legic(cmd))
    end

    -- apply MCD & MSN to plain data
    plainBytes[1] = MCD
    plainBytes[2] = MSN0
    plainBytes[3] = MSN1
    plainBytes[4] = MSN2
    plainBytes[5] = MCC

    -- prepare plainBytes for writing (xor plain data with new MCC)
    bytes = xorBytes(plainBytes, MCC)

    -- write data to file
    if (writeOutputBytes(bytes, "myLegicClone.hex")) then
        WriteBytes = utils.input("enter number of bytes to write?", SegCrcs[#SegCrcs])

        -- load file into pm3-buffer
        cmd = 'hf legic eload myLegicClone.hex'
        core.console(cmd)

        -- write pm3-buffer to Tag
        for i=0, WriteBytes do
            if ( i<5 or i>6) then
                cmd = ('hf legic write o %02x d 01'):format(i)
                core.console(cmd)
            elseif (i == 6) then
                -- write DCF in reverse order (requires 'mosci-patch')
                cmd = 'hf legic write o 05 d 02'
                core.console(cmd)
            else
                print("skipping byte 0x05 - will be written next step")
            end
            utils.Sleep(0.2)
        end
    end
end

-- main function
function main(args)
    -- some variables
    local i = 0
    local oldcrc, newcrc, infile, outfile
    local bytes = {}
    local segments = {}

    -- parse arguments for the script
    for o, a in getopt.getopt(args, 'hwsdc:i:o:') do
        -- output file
        if o == 'o' then
            outfile = a
            ofs = true
            if (file_check(a)) then
                local answer = utils.confirm('\nthe output-file '..a..' already exists!\nthis will delete the previous content!\ncontinue?')
                if (answer==false) then return oops('quiting') end
            end
        end
        -- input file
        if o == 'i' then
            infile = a
            if (file_check(infile)==false) then
                return oops('input file: '..infile..' not found')
            else
                bytes = getInputBytes(infile)
                oldcrc = bytes[5]
                ifs = true
                if (bytes == false) then return oops('couldnt get input bytes') end
            end
            i = i+1
        end
        -- new crc
        if o == 'c' then
            newcrc = a
            ncs = true
        end
        -- display segments switch
        if o == 'd' then ds = true; end
        -- display summary switch
        if o == 's' then ss = true; end
        -- write to tag switch
        if o == 'w' then ws = true; end
        -- help
        if o == 'h' then return help() end
    end

    if (not ifs) then return oops('option -i <input file> is required but missing') end

    -- bytes to plain
    bytes = xorBytes(bytes, oldcrc)

    -- show segments (works only on plain bytes)
    if (ds) then
        print("+------------------------------------------- Segments -------------------------------------------+")
        displaySegments(bytes);
    end

    if (ofs and ncs) then
        -- xor bytes with new crc
        newBytes = xorBytes(bytes, newcrc)
        -- write output
        if (writeOutputBytes(newBytes, outfile)) then
            -- show summary if requested
            if (ss) then
                -- information
                res = "\n+-------------------------------------------- Summary -------------------------------------------+"
                res = res .."\ncreated clone_dump from\n\t"..infile.." crc: "..oldcrc.."\ndump_file:"
                res = res .."\n\t"..outfile.." crc: "..string.sub(newcrc,-2)
                res = res .."\nyou may load the new file with: hf legic load "..outfile
                res = res .."\n\nif you don't write to tag immediately ('-w' switch) you will need to recalculate each segmentCRC"
                res = res .."\nafter writing this dump to a tag!"
                res = res .."\n\na segmentCRC gets calculated over MCD,MSN0..3,Segment-Header0..3"
                res = res .."\ne.g. (based on Segment00 of the data from "..infile.."):"
                res = res .."\nhf legic crc8 "..bytes[1]..bytes[2]..bytes[3]..bytes[4]..bytes[23]..bytes[24]..bytes[25]..bytes[26]
                -- this can not be calculated without knowing the new MCD, MSN0..2
                print(res)
            end
        end
    else
        if (ss) then
            -- show why the output-file was not written
            print("\nnew file not written - some arguments are missing ..")
            print("output file: ".. (ofs and outfile or "not given"))
            print("new crc: ".. (ncs and newcrc or "not given"))
        end
    end
    -- write to tag
    if (ws and #bytes == 1024) then
            writeToTag(bytes)
    end
end

-- call main with arguments
main(args)