util.parse_URI: allow bip21 with lightning key without fallback addr

We would reject bip21 URIs that contained both an "address=" and a "lightning=" key with a bolt11 invoice,
where the bolt11 invoice did not contain a fallback address.

electrum/tests/test_util.py

@@ -5,9 +5,9 @@ from electrum.util import (format_satoshis, format_fee_satoshis, parse_URI,
                            is_hash256_str, chunks, is_ip_address, list_enabled_bits,
                            format_satoshis_plain, is_private_netaddress, is_hex_str,
                            is_integer, is_non_negative_integer, is_int_or_float,
-                           is_non_negative_int_or_float, is_subpath)
+                           is_non_negative_int_or_float, is_subpath, InvalidBitcoinURI)
 
-from . import ElectrumTestCase
+from . import ElectrumTestCase, as_testnet
 
 
 class TestUtil(ElectrumTestCase):
@@ -147,9 +147,37 @@ class TestUtil(ElectrumTestCase):
     def test_parse_URI_invalid(self):
         self.assertRaises(BaseException, parse_URI, 'notbitcoin:15mKKb2eos1hWa6tisdPwwDC1a5J1y9nma')
 
-    def test_parse_URI_parameter_polution(self):
+    def test_parse_URI_parameter_pollution(self):
         self.assertRaises(Exception, parse_URI, 'bitcoin:15mKKb2eos1hWa6tisdPwwDC1a5J1y9nma?amount=0.0003&label=test&amount=30.0')
 
+    @as_testnet
+    def test_parse_URI_lightning_consistency(self):
+        # bip21 uri that *only* includes a "lightning" key. LN part does not have fallback address
+        self._do_test_parse_URI('bitcoin:?lightning=lntb700u1p3kqy0cpp5azvqy3wez7hcz3ka7tpqqvw5mpsa7fknxl4ca7a7669kswhf0hgqsp5qxhxul9k88w2nsk643elzuu4nepwkq052ek79esmz47yj6lfrhuqdqvw3jhxapjxcmscqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqyznyzw55q63yytup920n9qcsnh6qqht48maapzgadll2qy5vheeq26crapt0rcv9aqmpm93ljkapgtc05keud9jhlasns795fylfdjsphud9uh',
+                                {'lightning': 'lntb700u1p3kqy0cpp5azvqy3wez7hcz3ka7tpqqvw5mpsa7fknxl4ca7a7669kswhf0hgqsp5qxhxul9k88w2nsk643elzuu4nepwkq052ek79esmz47yj6lfrhuqdqvw3jhxapjxcmscqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqyznyzw55q63yytup920n9qcsnh6qqht48maapzgadll2qy5vheeq26crapt0rcv9aqmpm93ljkapgtc05keud9jhlasns795fylfdjsphud9uh'})
+        # bip21 uri that *only* includes a "lightning" key. LN part has fallback address
+        self._do_test_parse_URI('bitcoin:?lightning=lntb700u1p3kqy26pp5l7rj7w0u5sdsj24umzdlhdhkk8a597sn865rhap4h4jenjefdk7ssp5d9zjr96ezp89gsyenfse5f4jn9ls29p0awvp0zxlt6tpzn2m3j5qdqvw3jhxapjxcmqcqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqfppqu5ua3szskclyd48wlfdwfd32j65phxy9vu8dmmk3u20u0e0yqw484xzn4hc3cux6kk2wenhw7zy0mseu9ntpk9l4fws2d46svzszrc6mqy535740ks9j22w67fw0x4dt8w2hhzspcqakql',
+                                {'lightning': 'lntb700u1p3kqy26pp5l7rj7w0u5sdsj24umzdlhdhkk8a597sn865rhap4h4jenjefdk7ssp5d9zjr96ezp89gsyenfse5f4jn9ls29p0awvp0zxlt6tpzn2m3j5qdqvw3jhxapjxcmqcqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqfppqu5ua3szskclyd48wlfdwfd32j65phxy9vu8dmmk3u20u0e0yqw484xzn4hc3cux6kk2wenhw7zy0mseu9ntpk9l4fws2d46svzszrc6mqy535740ks9j22w67fw0x4dt8w2hhzspcqakql'})
+        # bip21 uri that includes "lightning" key. LN part does not have fallback address
+        self._do_test_parse_URI('bitcoin:tb1qu5ua3szskclyd48wlfdwfd32j65phxy9yf7ytl?amount=0.0007&message=test266&lightning=lntb700u1p3kqy0cpp5azvqy3wez7hcz3ka7tpqqvw5mpsa7fknxl4ca7a7669kswhf0hgqsp5qxhxul9k88w2nsk643elzuu4nepwkq052ek79esmz47yj6lfrhuqdqvw3jhxapjxcmscqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqyznyzw55q63yytup920n9qcsnh6qqht48maapzgadll2qy5vheeq26crapt0rcv9aqmpm93ljkapgtc05keud9jhlasns795fylfdjsphud9uh',
+                                {'address': 'tb1qu5ua3szskclyd48wlfdwfd32j65phxy9yf7ytl',
+                                 'amount': 70000,
+                                 'lightning': 'lntb700u1p3kqy0cpp5azvqy3wez7hcz3ka7tpqqvw5mpsa7fknxl4ca7a7669kswhf0hgqsp5qxhxul9k88w2nsk643elzuu4nepwkq052ek79esmz47yj6lfrhuqdqvw3jhxapjxcmscqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqyznyzw55q63yytup920n9qcsnh6qqht48maapzgadll2qy5vheeq26crapt0rcv9aqmpm93ljkapgtc05keud9jhlasns795fylfdjsphud9uh',
+                                 'memo': 'test266',
+                                 'message': 'test266'})
+        # bip21 uri that includes "lightning" key. LN part has fallback address
+        self._do_test_parse_URI('bitcoin:tb1qu5ua3szskclyd48wlfdwfd32j65phxy9yf7ytl?amount=0.0007&message=test266&lightning=lntb700u1p3kqy26pp5l7rj7w0u5sdsj24umzdlhdhkk8a597sn865rhap4h4jenjefdk7ssp5d9zjr96ezp89gsyenfse5f4jn9ls29p0awvp0zxlt6tpzn2m3j5qdqvw3jhxapjxcmqcqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqfppqu5ua3szskclyd48wlfdwfd32j65phxy9vu8dmmk3u20u0e0yqw484xzn4hc3cux6kk2wenhw7zy0mseu9ntpk9l4fws2d46svzszrc6mqy535740ks9j22w67fw0x4dt8w2hhzspcqakql',
+                                {'address': 'tb1qu5ua3szskclyd48wlfdwfd32j65phxy9yf7ytl',
+                                 'amount': 70000,
+                                 'lightning': 'lntb700u1p3kqy26pp5l7rj7w0u5sdsj24umzdlhdhkk8a597sn865rhap4h4jenjefdk7ssp5d9zjr96ezp89gsyenfse5f4jn9ls29p0awvp0zxlt6tpzn2m3j5qdqvw3jhxapjxcmqcqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqfppqu5ua3szskclyd48wlfdwfd32j65phxy9vu8dmmk3u20u0e0yqw484xzn4hc3cux6kk2wenhw7zy0mseu9ntpk9l4fws2d46svzszrc6mqy535740ks9j22w67fw0x4dt8w2hhzspcqakql',
+                                 'memo': 'test266',
+                                 'message': 'test266'})
+        # bip21 uri that includes "lightning" key. LN part has fallback address BUT it mismatches the top-level address
+        self.assertRaises(InvalidBitcoinURI, parse_URI, 'bitcoin:tb1qvu0c9xme0ul3gzx4nzqdgxsu25acuk9wvsj2j2?amount=0.0007&message=test266&lightning=lntb700u1p3kqy26pp5l7rj7w0u5sdsj24umzdlhdhkk8a597sn865rhap4h4jenjefdk7ssp5d9zjr96ezp89gsyenfse5f4jn9ls29p0awvp0zxlt6tpzn2m3j5qdqvw3jhxapjxcmqcqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqfppqu5ua3szskclyd48wlfdwfd32j65phxy9vu8dmmk3u20u0e0yqw484xzn4hc3cux6kk2wenhw7zy0mseu9ntpk9l4fws2d46svzszrc6mqy535740ks9j22w67fw0x4dt8w2hhzspcqakql')
+        # bip21 uri that includes "lightning" key. top-level amount mismatches LN amount
+        self.assertRaises(InvalidBitcoinURI, parse_URI, 'bitcoin:tb1qu5ua3szskclyd48wlfdwfd32j65phxy9yf7ytl?amount=0.0008&message=test266&lightning=lntb700u1p3kqy26pp5l7rj7w0u5sdsj24umzdlhdhkk8a597sn865rhap4h4jenjefdk7ssp5d9zjr96ezp89gsyenfse5f4jn9ls29p0awvp0zxlt6tpzn2m3j5qdqvw3jhxapjxcmqcqzynxq8zals8sq9q7sqqqqqqqqqqqqqqqqqqqqqqqqq9qsqfppqu5ua3szskclyd48wlfdwfd32j65phxy9vu8dmmk3u20u0e0yqw484xzn4hc3cux6kk2wenhw7zy0mseu9ntpk9l4fws2d46svzszrc6mqy535740ks9j22w67fw0x4dt8w2hhzspcqakql')
+
+
     def test_is_hash256_str(self):
         self.assertTrue(is_hash256_str('09a4c03e3bdf83bbe3955f907ee52da4fc12f4813d459bc75228b64ad08617c7'))
         self.assertTrue(is_hash256_str('2A5C3F4062E4F2FCCE7A1C7B4310CB647B327409F580F4ED72CB8FC0B1804DFA'))

electrum/util.py

@@ -1033,16 +1033,17 @@ def parse_URI(uri: str, on_pr: Callable = None, *, loop=None) -> dict:
         except Exception as e:
             raise InvalidBitcoinURI(f"failed to parse 'sig' field: {repr(e)}") from e
     if 'lightning' in out:
-        try:
-            lnaddr = lndecode(out['lightning'])
-            amount_sat = out.get('amount')
-            if amount_sat:
-                assert int(lnaddr.get_amount_sat()) == amount_sat
-            address = out.get('address')
-            if address:
-                assert lnaddr.get_fallback_address() == address
-        except Exception as e:
-            raise InvalidBitcoinURI(f"Inconsistent lightning field: {repr(e)}") from e
+        lnaddr = lndecode(out['lightning'])
+        amount_sat = out.get('amount')
+        if amount_sat:
+            # allow small leeway due to msat precision
+            if abs(amount_sat - int(lnaddr.get_amount_sat())) > 1:
+                raise InvalidBitcoinURI("Inconsistent lightning field in bip21: amount")
+        address = out.get('address')
+        ln_fallback_addr = lnaddr.get_fallback_address()
+        if address and ln_fallback_addr:
+            if ln_fallback_addr != address:
+                raise InvalidBitcoinURI("Inconsistent lightning field in bip21: address")
 
     r = out.get('r')
     sig = out.get('sig')