scripts/bootloader: Add ed25519/sha512 to scripts

Python scripts implementing ed25519 and sha512 support needed
for nsib image signing.

Signed-off-by: Lukasz Fundakowski <[email protected]>

Author: fundakol

scripts/bootloader/do_sign.py

@@ -3,37 +3,103 @@
 # Copyright (c) 2018 Nordic Semiconductor ASA
 #
 # SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+from __future__ import annotations
 
-
-import sys
 import argparse
+import contextlib
 import hashlib
-from ecdsa import SigningKey
+import sys
+from pathlib import Path
+from typing import BinaryIO, Generator
+
+from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
+from cryptography.hazmat.primitives.serialization import load_pem_private_key
+from ecdsa.keys import SigningKey  # type: ignore[import-untyped]
+from intelhex import IntelHex  # type: ignore[import-untyped]
 
 
-def parse_args():
+def parse_args(argv=None):
     parser = argparse.ArgumentParser(
         description='Sign data from stdin or file.',
         formatter_class=argparse.RawDescriptionHelpFormatter,
-        allow_abbrev=False)
+        allow_abbrev=False
+    )
 
-    parser.add_argument('-k', '--private-key', required=True, type=argparse.FileType('rb'),
+    parser.add_argument('-k', '--private-key', required=True, type=Path,
                         help='Private key to use.')
     parser.add_argument('-i', '--in', '-in', required=False, dest='infile',
-                        type=argparse.FileType('rb'), default=sys.stdin.buffer,
+                        type=Path, default=sys.stdin.buffer,
                         help='Sign the contents of the specified file instead of stdin.')
     parser.add_argument('-o', '--out', '-out', required=False, dest='outfile',
-                        type=argparse.FileType('wb'), default=sys.stdout.buffer,
+                        type=Path, default=None,
                         help='Write the signature to the specified file instead of stdout.')
+    parser.add_argument(
+        '--algorithm', '-a', dest='algorithm',
+        help='Signing algorithm (default: %(default)s)',
+        action='store', choices=['ecdsa', 'ed25519'], default='ecdsa',
+    )
 
-    args = parser.parse_args()
+    args = parser.parse_args(argv)
 
     return args
 
 
-if __name__ == '__main__':
-    args = parse_args()
-    private_key = SigningKey.from_pem(args.private_key.read())
-    data = args.infile.read()
+@contextlib.contextmanager
+def open_stream(output_file: Path | None = None) -> Generator[BinaryIO, None, None]:
+    if output_file is not None:
+        stream = open(output_file, 'wb')
+        try:
+            yield stream
+        finally:
+            stream.close()
+    else:
+        yield sys.stdout.buffer
+
+
+def hex_to_binary(input_hex_file: str) -> bytes:
+    ih = IntelHex(input_hex_file)
+    ih.padding = 0xff  # Allows hashing with empty regions
+    data = ih.tobinstr()
+    return data
+
+
+def sign_with_ecdsa(
+    private_key_file: Path, input_file: Path, output_file: Path | None = None
+) -> int:
+    with open(private_key_file, 'r') as f:
+        private_key = SigningKey.from_pem(f.read())
+    with open(input_file, 'rb') as f:
+        data = f.read()
     signature = private_key.sign(data, hashfunc=hashlib.sha256)
-    args.outfile.write(signature)
+    with open_stream(output_file) as stream:
+        stream.write(signature)
+    return 0
+
+
+def sign_with_ed25519(
+    private_key_file: Path, input_file: Path, output_file: Path | None = None
+) -> int:
+    with open(private_key_file, 'rb') as f:
+        private_key: Ed25519PrivateKey = load_pem_private_key(f.read(), password=None)  # type: ignore[assignment]
+    if str(input_file).endswith('.hex'):
+        data = hex_to_binary(str(input_file))
+    else:
+        with open(input_file, 'rb') as f:
+            data = f.read()
+    signature = private_key.sign(data)
+    with open_stream(output_file) as stream:
+        stream.write(signature)
+    return 0
+
+
+def main(argv=None) -> int:
+    args = parse_args(argv)
+    if args.algorithm == 'ecdsa':
+        return sign_with_ecdsa(args.private_key, args.infile, args.outfile)
+    if args.algorithm == 'ed25519':
+        return sign_with_ed25519(args.private_key, args.infile, args.outfile)
+    return 1
+
+
+if __name__ == '__main__':
+    sys.exit(main())

scripts/bootloader/hash.py

@@ -4,11 +4,20 @@
 #
 # SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 
+"""
+Hash content of a file.
+"""
 
+import argparse
 import hashlib
 import sys
-import argparse
-from intelhex import IntelHex
+
+from intelhex import IntelHex  # type: ignore[import-untyped]
+
+HASH_FUNCTION_FACTORY = {
+    'sha256': hashlib.sha256,
+    'sha512': hashlib.sha512,
+}
 
 
 def parse_args():
@@ -17,20 +26,37 @@ def parse_args():
         formatter_class=argparse.RawDescriptionHelpFormatter,
         allow_abbrev=False)
 
-    parser.add_argument('--infile', '-i', '--in', '-in', required=True,
-                        help='Hash the contents of the specified file. If a *.hex file is given, the contents will '
-                             'first be converted to binary, with all non-specified area being set to 0xff. '
-                             'For all other file types, no conversion is done.')
-    return parser.parse_args()
+    parser.add_argument(
+        '--infile', '-i', '--in', '-in', required=True,
+        help='Hash the contents of the specified file. If a *.hex file is given, the contents will '
+             'first be converted to binary, with all non-specified area being set to 0xff. '
+             'For all other file types, no conversion is done.'
+    )
+    parser.add_argument(
+        '--type', '-t', dest='hash_function', help='Hash function (default: %(default)s)',
+        action='store', choices=HASH_FUNCTION_FACTORY.keys(), default='sha256'
+    )
 
+    return parser.parse_args()
 
-if __name__ == '__main__':
-    args = parse_args()
 
-    if args.infile.endswith('.hex'):
-        ih = IntelHex(args.infile)
+def generate_hash_digest(file: str, hash_function_name: str) -> bytes:
+    if file.endswith('.hex'):
+        ih = IntelHex(file)
         ih.padding = 0xff  # Allows hashing with empty regions
         to_hash = ih.tobinstr()
     else:
-        to_hash = open(args.infile, 'rb').read()
-    sys.stdout.buffer.write(hashlib.sha256(to_hash).digest())
+        to_hash = open(file, 'rb').read()
+
+    hash_function = HASH_FUNCTION_FACTORY[hash_function_name]
+    return hash_function(to_hash).digest()
+
+
+def main():
+    args = parse_args()
+    sys.stdout.buffer.write(generate_hash_digest(args.infile, args.hash_function))
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())