My Marlin configs for Fabrikator Mini and CTC i3 Pro B
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chitu_crypt.py 3.7KB

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  1. import os
  2. import struct
  3. Import("env")
  4. # Relocate firmware from 0x08000000 to 0x08008800
  5. for define in env['CPPDEFINES']:
  6. if define[0] == "VECT_TAB_ADDR":
  7. env['CPPDEFINES'].remove(define)
  8. env['CPPDEFINES'].append(("VECT_TAB_ADDR", "0x8008800"))
  9. custom_ld_script = os.path.abspath("buildroot/share/PlatformIO/ldscripts/chitu_f103.ld")
  10. for i, flag in enumerate(env["LINKFLAGS"]):
  11. if "-Wl,-T" in flag:
  12. env["LINKFLAGS"][i] = "-Wl,-T" + custom_ld_script
  13. elif flag == "-T":
  14. env["LINKFLAGS"][i + 1] = custom_ld_script
  15. def calculate_crc(contents, seed):
  16. accumulating_xor_value = seed;
  17. for i in range(0, len(contents), 4):
  18. value = struct.unpack('<I', contents[ i : i + 4])[0]
  19. accumulating_xor_value = accumulating_xor_value ^ value
  20. return accumulating_xor_value
  21. def xor_block(r0, r1, block_number, block_size, file_key):
  22. # This is the loop counter
  23. loop_counter = 0x0
  24. # This is the key length
  25. key_length = 0x18
  26. # This is an initial seed
  27. xor_seed = 0x4bad
  28. # This is the block counter
  29. block_number = xor_seed * block_number
  30. #load the xor key from the file
  31. r7 = file_key
  32. for loop_counter in range(0, block_size):
  33. # meant to make sure different bits of the key are used.
  34. xor_seed = int(loop_counter/key_length)
  35. # IP is a scratch register / R12
  36. ip = loop_counter - (key_length * xor_seed)
  37. # xor_seed = (loop_counter * loop_counter) + block_number
  38. xor_seed = (loop_counter * loop_counter) + block_number
  39. # shift the xor_seed left by the bits in IP.
  40. xor_seed = xor_seed >> ip
  41. # load a byte into IP
  42. ip = r0[loop_counter]
  43. # XOR the seed with r7
  44. xor_seed = xor_seed ^ r7
  45. # and then with IP
  46. xor_seed = xor_seed ^ ip
  47. #Now store the byte back
  48. r1[loop_counter] = xor_seed & 0xFF
  49. #increment the loop_counter
  50. loop_counter = loop_counter + 1
  51. def encrypt_file(input, output_file, file_length):
  52. input_file = bytearray(input.read())
  53. block_size = 0x800
  54. key_length = 0x18
  55. file_key = 0xDAB27F94
  56. xor_crc = 0xef3d4323;
  57. # the input file is exepcted to be in chunks of 0x800
  58. # so round the size
  59. while len(input_file) % block_size != 0:
  60. input_file.extend(b'0x0')
  61. # write the file header
  62. output_file.write(struct.pack(">I", 0x443D2D3F))
  63. # encrypt the contents using a known file header key
  64. # write the file_key
  65. output_file.write(struct.pack(">I", 0x947FB2DA))
  66. #TODO - how to enforce that the firmware aligns to block boundaries?
  67. block_count = int(len(input_file) / block_size)
  68. print "Block Count is ", block_count
  69. for block_number in range(0, block_count):
  70. block_offset = (block_number * block_size)
  71. block_end = block_offset + block_size
  72. block_array = bytearray(input_file[block_offset: block_end])
  73. xor_block(block_array, block_array, block_number, block_size, file_key)
  74. for n in range (0, block_size):
  75. input_file[block_offset + n] = block_array[n]
  76. # update the expected CRC value.
  77. xor_crc = calculate_crc(block_array, xor_crc)
  78. # write CRC
  79. output_file.write(struct.pack("<I", xor_crc))
  80. # finally, append the encrypted results.
  81. output_file.write(input_file)
  82. return
  83. # Encrypt ${PROGNAME}.bin and save it as 'update.cbd'
  84. def encrypt(source, target, env):
  85. firmware = open(target[0].path, "rb")
  86. update = open(target[0].dir.path +'/update.cbd', "wb")
  87. length = os.path.getsize(target[0].path)
  88. encrypt_file(firmware, update, length)
  89. firmware.close()
  90. update.close()
  91. env.AddPostAction("$BUILD_DIR/${PROGNAME}.bin", encrypt);