300 lines
14 KiB
Python
300 lines
14 KiB
Python
#!/usr/bin/env python3
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# Utility to create image blobs for Corvette Secure Boot
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import argparse
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import sys
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from Crypto.Cipher import AES
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import array
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import hashlib
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import hmac
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import os
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import binascii
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import importlib
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from am_defines import *
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#from keys_info import keyTblAes, keyTblHmac, minAesKeyIdx, maxAesKeyIdx, minHmacKeyIdx, maxHmacKeyIdx, INFO_KEY
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#******************************************************************************
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#
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# Generate the image blob as per command line parameters
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#
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#******************************************************************************
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def process(loadaddress, appFile, magicNum, crcI, crcB, authI, authB, protection, authKeyIdx, output, encKeyIdx, version, erasePrev, child0, child1, authalgo, encalgo, keyFile):
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app_binarray = bytearray()
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# Open the file, and read it into an array of integers.
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with appFile as f_app:
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app_binarray.extend(f_app.read())
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f_app.close()
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filenames = keyFile.split('.')
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keys = importlib.import_module(filenames[0])
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encVal = 0
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if (encalgo != 0):
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encVal = 1
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if ((encKeyIdx < keys.minAesKeyIdx) or (encKeyIdx > keys.maxAesKeyIdx)):
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am_print("Invalid encKey Idx ", encKeyIdx, level=AM_PRINT_LEVEL_ERROR);
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return
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if (encalgo == 2):
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if (encKeyIdx & 0x1):
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am_print("Invalid encKey Idx ", encKeyIdx, level=AM_PRINT_LEVEL_ERROR);
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return
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keySize = 32
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else:
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keySize = 16
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if (authalgo != 0):
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if ((authKeyIdx < keys.minHmacKeyIdx) or (authKeyIdx > keys.maxHmacKeyIdx) or (authKeyIdx & 0x1)):
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am_print("Invalid authKey Idx ", authKeyIdx, level=AM_PRINT_LEVEL_ERROR);
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return
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if (magicNum == AM_IMAGE_MAGIC_MAIN):
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hdr_length = AM_IMAGEHDR_SIZE_MAIN; #fixed header length
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elif ((magicNum == AM_IMAGE_MAGIC_CHILD) or (magicNum == AM_IMAGE_MAGIC_CUSTPATCH) or (magicNum == AM_IMAGE_MAGIC_NONSECURE) or (magicNum == AM_IMAGE_MAGIC_INFO0)):
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hdr_length = AM_IMAGEHDR_SIZE_AUX; #fixed header length
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else:
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am_print("magic number", hex(magicNum), " not supported", level=AM_PRINT_LEVEL_ERROR)
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return
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am_print("Header Size = ", hex(hdr_length))
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#generate mutable byte array for the header
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hdr_binarray = bytearray([0x00]*hdr_length);
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orig_app_length = (len(app_binarray))
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am_print("original app_size ",hex(orig_app_length), "(",orig_app_length,")")
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am_print("load_address ",hex(loadaddress), "(",loadaddress,")")
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if (loadaddress & 0x3):
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am_print("load address needs to be word aligned", level=AM_PRINT_LEVEL_ERROR)
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return
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if (loadaddress & (FLASH_PAGE_SIZE - 1)):
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am_print("WARNING!!! - load address is not page aligned", level=AM_PRINT_LEVEL_ERROR)
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if (magicNum == AM_IMAGE_MAGIC_INFO0):
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if (orig_app_length & 0x3):
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am_print("INFO0 blob length needs to be multiple of 4", level=AM_PRINT_LEVEL_ERROR)
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return
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if ((loadaddress + orig_app_length) > INFO_SIZE_BYTES):
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am_print("INFO0 Offset and length exceed size", level=AM_PRINT_LEVEL_ERROR)
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return
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if (encVal == 1):
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block_size = AM_SECBOOT_AESCBC_BLOCK_SIZE_BYTES
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app_binarray = pad_to_block_size(app_binarray, block_size, 1)
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else:
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# Add Padding
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app_binarray = pad_to_block_size(app_binarray, 4, 0)
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app_length = (len(app_binarray))
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am_print("app_size ",hex(app_length), "(",app_length,")")
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# Create Image blobs
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# w0
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blobLen = hdr_length + app_length
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w0 = (magicNum << 24) | ((encVal & 0x1) << 23) | blobLen
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am_print("w0 =", hex(w0))
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fill_word(hdr_binarray, 0, w0)
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# w2
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securityVal = ((authI << 1) | crcI) << 4 | (authB << 1) | crcB
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am_print("Security Value ", hex(securityVal))
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w2 = ((securityVal << 24) & 0xff000000) | ((authalgo) & 0xf) | ((authKeyIdx << 4) & 0xf0) | ((encalgo << 8) & 0xf00) | ((encKeyIdx << 12) & 0xf000)
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fill_word(hdr_binarray, 8, w2)
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am_print("w2 = ",hex(w2))
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if (magicNum == AM_IMAGE_MAGIC_INFO0):
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# Insert the INFO0 size and offset
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addrWord = ((orig_app_length>>2) << 16) | ((loadaddress>>2) & 0xFFFF)
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versionKeyWord = keys.INFO_KEY
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else:
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# Insert the application binary load address.
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addrWord = loadaddress | (protection & 0x3)
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# Initialize versionKeyWord
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versionKeyWord = (version & 0x7FFF) | ((erasePrev & 0x1) << 15)
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am_print("addrWord = ",hex(addrWord))
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fill_word(hdr_binarray, AM_IMAGEHDR_OFFSET_ADDR, addrWord)
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am_print("versionKeyWord = ",hex(versionKeyWord))
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fill_word(hdr_binarray, AM_IMAGEHDR_OFFSET_VERKEY, versionKeyWord)
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# Initialize child (Child Ptr/ Feature key)
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am_print("child0/feature = ",hex(child0))
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fill_word(hdr_binarray, AM_IMAGEHDR_OFFSET_CHILDPTR, child0)
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am_print("child1 = ",hex(child1))
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fill_word(hdr_binarray, AM_IMAGEHDR_OFFSET_CHILDPTR + 4, child1)
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authKeyIdx = authKeyIdx - keys.minHmacKeyIdx
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if (authB != 0): # Authentication needed
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am_print("Boot Authentication Enabled")
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# am_print("Key used for HMAC")
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# am_print([hex(keys.keyTblHmac[authKeyIdx*AM_SECBOOT_KEYIDX_BYTES + n]) for n in range (0, AM_HMAC_SIG_SIZE)])
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# Initialize the clear image HMAC
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sigClr = compute_hmac(keys.keyTblHmac[authKeyIdx*AM_SECBOOT_KEYIDX_BYTES:(authKeyIdx*AM_SECBOOT_KEYIDX_BYTES+AM_HMAC_SIG_SIZE)], (hdr_binarray[AM_IMAGEHDR_START_HMAC:hdr_length] + app_binarray))
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am_print("HMAC Clear")
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am_print([hex(n) for n in sigClr])
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# Fill up the HMAC
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for x in range(0, AM_HMAC_SIG_SIZE):
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hdr_binarray[AM_IMAGEHDR_OFFSET_SIGCLR + x] = sigClr[x]
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# All the header fields part of the encryption are now final
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if (encVal == 1):
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am_print("Encryption Enabled")
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encKeyIdx = encKeyIdx - keys.minAesKeyIdx
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ivValAes = os.urandom(AM_SECBOOT_AESCBC_BLOCK_SIZE_BYTES)
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am_print("Initialization Vector")
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am_print([hex(ivValAes[n]) for n in range (0, AM_SECBOOT_AESCBC_BLOCK_SIZE_BYTES)])
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keyAes = os.urandom(keySize)
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am_print("AES Key used for encryption")
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am_print([hex(keyAes[n]) for n in range (0, keySize)])
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# Encrypted Part
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am_print("Encrypting blob of size " , (hdr_length - AM_IMAGEHDR_START_ENCRYPT + app_length))
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enc_binarray = encrypt_app_aes((hdr_binarray[AM_IMAGEHDR_START_ENCRYPT:hdr_length] + app_binarray), keyAes, ivValAes)
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# am_print("Key used for encrypting AES Key")
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# am_print([hex(keys.keyTblAes[encKeyIdx*keySize + n]) for n in range (0, keySize)])
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# Encrypted Key
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enc_key = encrypt_app_aes(keyAes, keys.keyTblAes[encKeyIdx*keySize:encKeyIdx*keySize + keySize], ivVal0)
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am_print("Encrypted Key")
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am_print([hex(enc_key[n]) for n in range (0, keySize)])
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# Fill up the IV
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for x in range(0, AM_SECBOOT_AESCBC_BLOCK_SIZE_BYTES):
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hdr_binarray[AM_IMAGEHDR_OFFSET_IV + x] = ivValAes[x]
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# Fill up the Encrypted Key
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for x in range(0, keySize):
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hdr_binarray[AM_IMAGEHDR_OFFSET_KEK + x] = enc_key[x]
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else:
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enc_binarray = hdr_binarray[AM_IMAGEHDR_START_ENCRYPT:hdr_length] + app_binarray
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if (authI != 0): # Install Authentication needed
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am_print("Install Authentication Enabled")
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# am_print("Key used for HMAC")
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# am_print([hex(keys.keyTblHmac[authKeyIdx*AM_SECBOOT_KEYIDX_BYTES + n]) for n in range (0, AM_HMAC_SIG_SIZE)])
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# Initialize the top level HMAC
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sig = compute_hmac(keys.keyTblHmac[authKeyIdx*AM_SECBOOT_KEYIDX_BYTES:(authKeyIdx*AM_SECBOOT_KEYIDX_BYTES+AM_HMAC_SIG_SIZE)], (hdr_binarray[AM_IMAGEHDR_START_HMAC_INST:AM_IMAGEHDR_START_ENCRYPT] + enc_binarray))
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am_print("Generated Signature")
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am_print([hex(n) for n in sig])
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# Fill up the HMAC
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for x in range(0, AM_HMAC_SIG_SIZE):
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hdr_binarray[AM_IMAGEHDR_OFFSET_SIG + x] = sig[x]
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# compute the CRC for the blob - this is done on a clear image
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crc = crc32(hdr_binarray[AM_IMAGEHDR_START_CRC:hdr_length] + app_binarray)
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am_print("crc = ",hex(crc));
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w1 = crc
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fill_word(hdr_binarray, AM_IMAGEHDR_OFFSET_CRC, w1)
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# now output all three binary arrays in the proper order
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output = output + '.bin'
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am_print("Writing to file ", output)
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with open(output, mode = 'wb') as out:
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out.write(hdr_binarray[0:AM_IMAGEHDR_START_ENCRYPT])
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out.write(enc_binarray)
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def parse_arguments():
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parser = argparse.ArgumentParser(description =
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'Generate Corvette Image Blob')
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parser.add_argument('--bin', dest='appFile', type=argparse.FileType('rb'),
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help='binary file (blah.bin)')
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parser.add_argument('--load-address', dest='loadaddress', type=auto_int, default=hex(AM_SECBOOT_DEFAULT_NONSECURE_MAIN),
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help='Load address of the binary.')
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parser.add_argument('--magic-num', dest='magic_num', default=hex(AM_IMAGE_MAGIC_NONSECURE),
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type=lambda x: x.lower(),
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# type = str.lower,
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choices = [
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hex(AM_IMAGE_MAGIC_MAIN),
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hex(AM_IMAGE_MAGIC_CHILD),
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hex(AM_IMAGE_MAGIC_CUSTPATCH),
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hex(AM_IMAGE_MAGIC_NONSECURE),
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hex(AM_IMAGE_MAGIC_INFO0)
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],
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help = 'Magic Num ('
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+ str(hex(AM_IMAGE_MAGIC_MAIN)) + ': Main, '
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+ str(hex(AM_IMAGE_MAGIC_CHILD)) + ': Child, '
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+ str(hex(AM_IMAGE_MAGIC_CUSTPATCH)) + ': CustOTA, '
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+ str(hex(AM_IMAGE_MAGIC_NONSECURE)) + ': NonSecure, '
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+ str(hex(AM_IMAGE_MAGIC_INFO0)) + ': Info0) '
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'- default[Main]'
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)
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parser.add_argument('-o', dest = 'output', default='outimage',
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help = 'Output filename (without the extension)')
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parser.add_argument('--authkey', dest = 'authkey', type=auto_int, default=(AM_SECBOOT_MIN_KEYIDX_INFO0), choices = range(AM_SECBOOT_MIN_KEYIDX_INFO0, AM_SECBOOT_MAX_KEYIDX_INFO0 + 1),
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help = 'Authentication Key Idx? (' + str(AM_SECBOOT_MIN_KEYIDX_INFO0) + ' to ' + str(AM_SECBOOT_MAX_KEYIDX_INFO0) + ')')
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parser.add_argument('--kek', dest = 'kek', type=auto_int, default=(AM_SECBOOT_MIN_KEYIDX_INFO0), choices = range(AM_SECBOOT_MIN_KEYIDX_INFO0, AM_SECBOOT_MAX_KEYIDX_INFO0 + 1),
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help = 'KEK Index? (' + str(AM_SECBOOT_MIN_KEYIDX_INFO0) + ' to ' + str(AM_SECBOOT_MAX_KEYIDX_INFO0) + ')')
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parser.add_argument('--authalgo', dest = 'authalgo', type=auto_int, default=0, choices=range(0, AM_SECBOOT_AUTH_ALGO_MAX+1),
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help = helpAuthAlgo)
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parser.add_argument('--encalgo', dest = 'encalgo', type=auto_int, default=0, choices = range(0, AM_SECBOOT_ENC_ALGO_MAX+1),
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help = helpEncAlgo)
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parser.add_argument('--child0', dest = 'child0', type=auto_int, default=hex(0xFFFFFFFF),
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help = 'child (blobPtr#0 for Main / feature key for AM3P)')
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parser.add_argument('--child1', dest = 'child1', type=auto_int, default=hex(0xFFFFFFFF),
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help = 'child (blobPtr#1 for Main)')
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parser.add_argument('--version', dest = 'version', type=auto_int, default=0,
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help = 'version (15 bit)')
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parser.add_argument('--crcI', dest = 'crcI', type=auto_int, default=1, choices=[0,1],
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help = 'Install CRC check enabled (Default = Y)?')
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parser.add_argument('--crcB', dest = 'crcB', type=auto_int, default=0, choices=[0,1],
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help = 'Boot CRC check enabled (Default = N)?')
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parser.add_argument('--authI', dest = 'authI', type=auto_int, default=0, choices=[0,1],
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help = 'Install Authentication check enabled (Default = N)?')
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parser.add_argument('--authB', dest = 'authB', type=auto_int, default=0, choices=[0,1],
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help = 'Boot Authentication check enabled (Default = N)?')
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parser.add_argument('--erasePrev', dest = 'erasePrev', type=auto_int, default=0, choices=[0,1],
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help = 'erasePrev (Valid only for main)')
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parser.add_argument('-p', dest = 'protection', type=auto_int, default=0, choices = [0x0, 0x1, 0x2, 0x3],
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help = 'protection info 2 bit C W')
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parser.add_argument('-k', type=str, dest='keyFile', nargs='?', default='keys_info.py',
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help='key file in specified format [default = keys_info.py]')
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parser.add_argument('--loglevel', dest='loglevel', type=auto_int, default=AM_PRINT_LEVEL_INFO,
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choices = range(AM_PRINT_LEVEL_MIN, AM_PRINT_LEVEL_MAX+1),
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help=helpPrintLevel)
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args = parser.parse_args()
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args.magic_num = int(args.magic_num, 16)
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return args
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#******************************************************************************
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#
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# Main function.
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#
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#******************************************************************************
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def main():
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# Read the arguments.
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args = parse_arguments()
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am_set_print_level(args.loglevel)
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process(args.loadaddress, args.appFile, args.magic_num, args.crcI, args.crcB, args.authI, args.authB, args.protection, args.authkey, args.output, args.kek, args.version, args.erasePrev, args.child0, args.child1, args.authalgo, args.encalgo, args.keyFile)
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if __name__ == '__main__':
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main()
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