1#!/usr/bin/env python 2# SPDX-License-Identifier: BSD-2-Clause 3# 4# Copyright (c) 2015, Linaro Limited 5# 6 7 8def get_args(): 9 import argparse 10 11 parser = argparse.ArgumentParser() 12 parser.add_argument( 13 '--prefix', 14 required=True, 15 help='Prefix for the public key exponent and modulus in c file') 16 17 parser.add_argument('--out', required=True, 18 help='Name of c file for the public key') 19 20 parser.add_argument('--key', required=True, help='Name of key file') 21 22 return parser.parse_args() 23 24 25def main(): 26 import array 27 from Crypto.PublicKey import RSA 28 from Crypto.Util.number import long_to_bytes 29 30 args = get_args() 31 32 f = open(args.key, 'r') 33 key = RSA.importKey(f.read()) 34 f.close 35 36 # Refuse public exponent with more than 32 bits. Otherwise the C 37 # compiler may simply truncate the value and proceed. 38 # This will lead to TAs seemingly having invalid signatures with a 39 # possible security issue for any e = k*2^32 + 1 (for any integer k). 40 if key.publickey().e > 0xffffffff: 41 raise ValueError( 42 'Unsupported large public exponent detected. ' + 43 'OP-TEE handles only public exponents up to 2^32 - 1.') 44 45 f = open(args.out, 'w') 46 47 f.write("#include <stdint.h>\n") 48 f.write("#include <stddef.h>\n\n") 49 50 f.write("const uint32_t " + args.prefix + "_exponent = " + 51 str(key.publickey().e) + ";\n\n") 52 53 f.write("const uint8_t " + args.prefix + "_modulus[] = {\n") 54 i = 0 55 for x in array.array("B", long_to_bytes(key.publickey().n)): 56 f.write("0x" + '{0:02x}'.format(x) + ",") 57 i = i + 1 58 if i % 8 == 0: 59 f.write("\n") 60 else: 61 f.write(" ") 62 f.write("};\n") 63 64 f.write("const size_t " + args.prefix + "_modulus_size = sizeof(" + 65 args.prefix + "_modulus);\n") 66 67 f.close() 68 69 70if __name__ == "__main__": 71 main() 72