147 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			147 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			Python
		
	
	
import nacl.signing
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import json
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import base64
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import requests
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import sys
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import srvlookup
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def encode_base64(input_bytes):
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    """Encode bytes as a base64 string without any padding."""
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    input_len = len(input_bytes)
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    output_len = 4 * ((input_len + 2) // 3) + (input_len + 2) % 3 - 2
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    output_bytes = base64.b64encode(input_bytes)
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    output_string = output_bytes[:output_len].decode("ascii")
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    return output_string
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def decode_base64(input_string):
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    """Decode a base64 string to bytes inferring padding from the length of the
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    string."""
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    input_bytes = input_string.encode("ascii")
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    input_len = len(input_bytes)
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    padding = b"=" * (3 - ((input_len + 3) % 4))
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    output_len = 3 * ((input_len + 2) // 4) + (input_len + 2) % 4 - 2
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    output_bytes = base64.b64decode(input_bytes + padding)
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    return output_bytes[:output_len]
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def encode_canonical_json(value):
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    return json.dumps(
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         value,
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         # Encode code-points outside of ASCII as UTF-8 rather than \u escapes
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         ensure_ascii=False,
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         # Remove unecessary white space.
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         separators=(',',':'),
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         # Sort the keys of dictionaries.
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         sort_keys=True,
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         # Encode the resulting unicode as UTF-8 bytes.
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     ).encode("UTF-8")
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def sign_json(json_object, signing_key, signing_name):
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    signatures = json_object.pop("signatures", {})
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    unsigned = json_object.pop("unsigned", None)
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    signed = signing_key.sign(encode_canonical_json(json_object))
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    signature_base64 = encode_base64(signed.signature)
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    key_id = "%s:%s" % (signing_key.alg, signing_key.version)
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    signatures.setdefault(signing_name, {})[key_id] = signature_base64
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    json_object["signatures"] = signatures
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    if unsigned is not None:
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        json_object["unsigned"] = unsigned
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    return json_object
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NACL_ED25519 = "ed25519"
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def decode_signing_key_base64(algorithm, version, key_base64):
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    """Decode a base64 encoded signing key
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    Args:
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        algorithm (str): The algorithm the key is for (currently "ed25519").
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        version (str): Identifies this key out of the keys for this entity.
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        key_base64 (str): Base64 encoded bytes of the key.
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    Returns:
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        A SigningKey object.
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    """
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    if algorithm == NACL_ED25519:
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        key_bytes = decode_base64(key_base64)
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        key = nacl.signing.SigningKey(key_bytes)
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        key.version = version
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        key.alg = NACL_ED25519
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        return key
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    else:
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        raise ValueError("Unsupported algorithm %s" % (algorithm,))
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def read_signing_keys(stream):
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    """Reads a list of keys from a stream
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    Args:
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        stream : A stream to iterate for keys.
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    Returns:
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        list of SigningKey objects.
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    """
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    keys = []
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    for line in stream:
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        algorithm, version, key_base64 = line.split()
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        keys.append(decode_signing_key_base64(algorithm, version, key_base64))
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    return keys
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def lookup(destination, path):
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    if ":" in destination:
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        return "https://%s%s" % (destination, path)
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    else:
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        try:
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            srv = srvlookup.lookup("matrix", "tcp", destination)[0]
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            return "https://%s:%d%s" % (srv.host, srv.port, path)
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        except:
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            return "https://%s:%d%s" % (destination, 8448, path)
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def get_json(origin_name, origin_key, destination, path):
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    request_json = {
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        "method": "GET",
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        "uri": path,
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        "origin": origin_name,
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        "destination": destination,
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    }
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    signed_json = sign_json(request_json, origin_key, origin_name)
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    authorization_headers = []
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    for key, sig in signed_json["signatures"][origin_name].items():
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        authorization_headers.append(bytes(
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            "X-Matrix origin=%s,key=\"%s\",sig=\"%s\"" % (
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                origin_name, key, sig,
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            )
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        ))
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    result = requests.get(
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        lookup(destination, path),
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        headers={"Authorization": authorization_headers[0]},
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        verify=False,
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    )
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    return result.json()
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def main():
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    origin_name, keyfile, destination, path = sys.argv[1:]
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    with open(keyfile) as f:
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        key = read_signing_keys(f)[0]
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    result = get_json(
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        origin_name, key, destination, "/_matrix/federation/v1/" + path
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    )
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    json.dump(result, sys.stdout)
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if __name__ == "__main__":
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    main()
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