SimpleJadePinServer/SimpleJadePinServer.py at main · Filiprogrammer/SimpleJadePinServer · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
#!/usr/bin/env python3

from http.server import BaseHTTPRequestHandler, HTTPServer
from hashlib import sha256
import argparse
import base64
import os
import wallycore as wally
import urllib.parse
import signal
import ssl
import sys
import json

tls_cert_path = "key_data/server.pem"
server_keys_path = "key_data/server_keys"
pins_path = "key_data/pins"

class GracefulExitHandler:
    def __init__(self, server):
        self.server = server
        signal.signal(signal.SIGTERM, self.graceful_shutdown)
        signal.signal(signal.SIGINT, self.graceful_shutdown)

    def graceful_shutdown(self, signum, frame):
        self.server.server_close()
        print("Server stopped")
        sys.exit(0)

class MyServer(BaseHTTPRequestHandler):
    def do_POST(self):
        content_len = int(self.headers.get('Content-length', '0'))
        post_body = self.rfile.read(content_len)
        try:
            params = json.loads(post_body)
        except json.JSONDecodeError:
            params = {}

        request = urllib.parse.urlparse(self.path)

        if request.path == "/set_pin":
            print("set_pin")

            if not 'data' in params:
                self.send_response(400)
                self.send_header("Content-type", "text/html")
                self.end_headers()
                self.wfile.write(bytes("<html><head><title>Bad request</title></head><body>Bad request</body></html>", "utf-8"))
                return

            data = base64.b64decode(params['data'])
            assert len(data) > 37
            cke = data[:33]
            replay_counter = data[33:37]
            encrypted_data = data[37:]

            private_key, public_key = generate_ec_key_pair(replay_counter, cke)

            payload = wally.aes_cbc_with_ecdh_key(private_key, None, encrypted_data, cke, b'blind_oracle_request', wally.AES_FLAG_DECRYPT)

            # set_pin requires client-passed entropy
            assert len(payload) == 32 + 32 + 65
            pin_secret = payload[:32]
            entropy = payload[32:64]
            sig = payload[64:]
            signed_msg = bytearray(sha256(cke + replay_counter + pin_secret + entropy).digest())
            pin_pubkey = wally.ec_sig_to_public_key(signed_msg, sig)

            pin_pubkey_hash = sha256(pin_pubkey).digest()

            replay_local = None
            try:
                _, _, _, replay_local = load_pin_fields(pin_pubkey_hash, pin_pubkey)

                # Enforce anti replay (client counter must be greater than the server counter)
                client_counter = int.from_bytes(replay_counter, byteorder='little', signed=False)
                server_counter = int.from_bytes(replay_local, byteorder='little', signed=False)
                assert client_counter > server_counter
            except FileNotFoundError:
                pass

            our_random = os.urandom(32)
            new_key = wally.hmac_sha256(our_random, entropy)

            hash_pin_secret = sha256(pin_secret).digest()
            replay_bytes = b'\x00\x00\x00\x00'
            save_pin_fields(pin_pubkey_hash, hash_pin_secret, new_key, pin_pubkey, 0, replay_bytes)
            aes_key = wally.hmac_sha256(new_key, pin_secret)

            iv = os.urandom(16)
            encrypted_key = wally.aes_cbc_with_ecdh_key(private_key, iv, aes_key, cke, b'blind_oracle_response', wally.AES_FLAG_ENCRYPT)

            self.send_response(200)
            self.send_header("Content-type", "application/json")
            self.end_headers()
            self.wfile.write(b'{"data":"' + base64.b64encode(encrypted_key) + b'"}')
        elif request.path == "/get_pin":
            print("get_pin")

            if not 'data' in params:
                self.send_response(400)
                self.send_header("Content-type", "text/html")
                self.end_headers()
                self.wfile.write(bytes("<html><head><title>Bad request</title></head><body>Bad request</body></html>", "utf-8"))
                return

            data = base64.b64decode(params['data'])
            assert len(data) > 37
            cke = data[:33]
            replay_counter = data[33:37]
            encrypted_data = data[37:]

            private_key, public_key = generate_ec_key_pair(replay_counter, cke)

            payload = wally.aes_cbc_with_ecdh_key(private_key, None, encrypted_data, cke, b'blind_oracle_request', wally.AES_FLAG_DECRYPT)

            # get_pin does not need client-passed entropy
            assert len(payload) == 32 + 65
            pin_secret = payload[:32]
            sig = payload[32:]
            signed_msg = bytearray(sha256(cke + replay_counter + pin_secret).digest())
            pin_pubkey = wally.ec_sig_to_public_key(signed_msg, sig)

            pin_pubkey_hash = sha256(pin_pubkey).digest()

            try:
                saved_hash_pin_secret, saved_key, counter, replay_local = load_pin_fields(pin_pubkey_hash, pin_pubkey)

                # Enforce anti replay (client counter must be greater than the server counter)
                client_counter = int.from_bytes(replay_counter, byteorder='little', signed=False)
                server_counter = int.from_bytes(replay_local, byteorder='little', signed=False)
                assert client_counter > server_counter
            except FileNotFoundError:
                # Return a random incorrect key to the Jade
                saved_key = os.urandom(32)
            else:
                hash_pin_secret = sha256(pin_secret).digest()

                if hash_pin_secret == saved_hash_pin_secret:
                    print("Correct pin on the " + str(counter + 1) + ". attempt")
                    save_pin_fields(pin_pubkey_hash, hash_pin_secret, saved_key, pin_pubkey, 0, replay_counter)
                else:
                    print("Wrong pin (" + str(counter + 1) + ". attempt)")

                    if counter >= 2:
                        os.remove(pins_path + "/" + bytes2hex(pin_pubkey_hash) + ".pin")
                        print("Too many wrong attempts")
                    else:
                        save_pin_fields(pin_pubkey_hash, saved_hash_pin_secret, saved_key, pin_pubkey, counter + 1, replay_counter)

                    # Return a random incorrect key to the Jade
                    saved_key = os.urandom(32)

            aes_key = wally.hmac_sha256(saved_key, pin_secret)

            iv = os.urandom(16)
            encrypted_key = wally.aes_cbc_with_ecdh_key(private_key, iv, aes_key, cke, b'blind_oracle_response', wally.AES_FLAG_ENCRYPT)

            self.send_response(200)
            self.send_header("Content-type", "application/json")
            self.end_headers()
            self.wfile.write(b'{"data":"' + base64.b64encode(encrypted_key) + b'"}')
        else:
            self.send_response(404)
            self.send_header("Content-type", "text/html")
            self.end_headers()
            self.wfile.write(bytes("<html><head><title>Not found</title></head><body>Not found</body></html>", "utf-8"))

    def do_GET(self):
        request = urllib.parse.urlparse(self.path)

        if request.path == "/qrcode.js":
            self.send_response(200)
            self.send_header("Content-type", "text/javascript")
            self.end_headers()

            with open("qrcode.js", "r") as file:
                self.wfile.write(bytes(file.read(), "utf-8"))
        elif request.path == "/":
            self.send_response(200)
            self.send_header("Content-type", "text/html")
            self.end_headers()

            with open("index.html", "r") as file:
                self.wfile.write(bytes(file.read(), "utf-8"))
        elif request.path == "/oracle_qr.html":
            self.send_response(200)
            self.send_header("Content-type", "text/html")
            self.end_headers()

            with open("oracle_qr.html", "r") as file:
                file_contents = file.read()
                file_contents = file_contents.replace("{STATIC_SERVER_PUBLIC_KEY}", bytes2hex(STATIC_SERVER_PUBLIC_KEY))
                self.wfile.write(bytes(file_contents, "utf-8"))
        else:
            self.send_response(404)
            self.send_header("Content-type", "text/html")
            self.end_headers()
            self.wfile.write(bytes("<html><head><title>Not found</title></head><body>Not found</body></html>", "utf-8"))

def save_pin_fields(pin_pubkey_hash, hash_pin_secret, aes_key, pin_pubkey, counter, replay_counter):
    storage_aes_key = wally.hmac_sha256(STATIC_SERVER_AES_PIN_DATA, pin_pubkey)
    count_bytes = counter.to_bytes(1)
    plaintext = hash_pin_secret + aes_key + count_bytes + replay_counter
    iv = os.urandom(16)
    encrypted = iv + wally.aes_cbc(storage_aes_key, iv, plaintext, wally.AES_FLAG_ENCRYPT)
    pin_auth_key = wally.hmac_sha256(STATIC_SERVER_AES_PIN_DATA, pin_pubkey_hash)
    version_bytes = b'\x01'
    hmac_payload = wally.hmac_sha256(pin_auth_key, version_bytes + encrypted)

    os.makedirs(pins_path, exist_ok=True)

    with open(pins_path + "/" + bytes2hex(pin_pubkey_hash) + ".pin", "wb") as f:
        f.write(version_bytes + hmac_payload + encrypted)

def load_pin_fields(pin_pubkey_hash, pin_pubkey):
    with open(pins_path + "/" + bytes2hex(pin_pubkey_hash) + ".pin", "rb") as f:
        data = f.read()

    assert len(data) == 129
    version_bytes = data[:1]
    assert version_bytes[0] == 1
    hmac_received = data[1:33]
    encrypted = data[33:]
    pin_auth_key = wally.hmac_sha256(STATIC_SERVER_AES_PIN_DATA, pin_pubkey_hash)
    hmac_payload = wally.hmac_sha256(pin_auth_key, version_bytes + encrypted)
    assert hmac_payload == hmac_received

    storage_aes_key = wally.hmac_sha256(STATIC_SERVER_AES_PIN_DATA, pin_pubkey)
    iv = encrypted[:16]
    plaintext = wally.aes_cbc(storage_aes_key, iv, encrypted[16:], wally.AES_FLAG_DECRYPT)
    assert len(plaintext) == 32 + 32 + 1 + 4

    saved_hash_pin_secret = plaintext[:32]
    saved_key = plaintext[32:64]
    counter = plaintext[64]
    replay_counter_persisted = plaintext[65:69]

    return saved_hash_pin_secret, saved_key, counter, replay_counter_persisted

def bytes2hex(byte_array):
    return ''.join('{:02x}'.format(x) for x in byte_array)

def hex2bytes(hex):
    return bytearray(bytes.fromhex(hex))

def generate_ec_key_pair(replay_counter, cke):
    tweak = sha256(wally.hmac_sha256(cke, replay_counter)).digest()
    private_key = wally.ec_private_key_bip341_tweak(STATIC_SERVER_PRIVATE_KEY, tweak, 0)
    wally.ec_private_key_verify(private_key)
    public_key = wally.ec_public_key_from_private_key(private_key)

    return private_key, public_key

def generate_private_key():
    while True:
        private_key = bytearray(os.urandom(32))
        try:
            wally.ec_private_key_verify(private_key)
            break
        except Exception:
            pass

    return private_key

def get_static_server_key_pair():
    os.makedirs(server_keys_path, exist_ok=True)
    private_key_path = server_keys_path + "/private.key"
    public_key_path = server_keys_path + "/public.key"

    if os.path.isfile(private_key_path):
        with open(private_key_path, "rb") as f:
            private_key = bytearray(f.read())
    else:
        private_key = generate_private_key()

        with open(private_key_path, "wb") as f:
            f.write(private_key)

    public_key = wally.ec_public_key_from_private_key(private_key)

    with open(public_key_path, "wb") as f:
        f.write(public_key)

    return private_key, public_key

if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Simple reimplementation of the blind_pin_server for the Blockstream Jade, "
                    "along with a basic web interface"
    )
    parser.add_argument(
        "-p", "--port",
        type=int, default=4443,
        help="port number to listen on"
    )
    parser.add_argument(
        "--tls",
        action=argparse.BooleanOptionalAction, default=True,
        help="whether to use HTTPS (HTTP over TLS) for secure access, required by modern browsers "
             "to enable webcam access on non-localhost connections. "
             "Enabled by default; use --no-tls to disable."
    )
    args = parser.parse_args()

    listen_ip = "0.0.0.0"
    server = HTTPServer((listen_ip, args.port), MyServer)

    if args.tls:
        if not os.path.isfile(tls_cert_path):
            print(
                f"TLS certificate not found at {tls_cert_path}. "
                "Either provide a certificate or use --no-tls to disable TLS. "
                "Note that TLS is required by modern browsers to enable webcam access on "
                "non-localhost connections."
            )
            sys.exit(1)

        ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
        ssl_context.load_cert_chain(certfile=tls_cert_path)
        server.socket = ssl_context.wrap_socket(server.socket, server_side=True)

    print(f"Server starting on {'https' if args.tls else 'http'}://{listen_ip}:{args.port}")

    global STATIC_SERVER_PRIVATE_KEY, STATIC_SERVER_PUBLIC_KEY, STATIC_SERVER_AES_PIN_DATA
    STATIC_SERVER_PRIVATE_KEY, STATIC_SERVER_PUBLIC_KEY = get_static_server_key_pair()
    STATIC_SERVER_AES_PIN_DATA = wally.hmac_sha256(STATIC_SERVER_PRIVATE_KEY, b'pin_data')

    GracefulExitHandler(server)
    server.serve_forever()