Merge bitcoin/bitcoin#16807: Let validateaddress locate error in Bech32 address

88cc4810926e4f5af6757ee1b0eed61abda3d746 Modify copyright header on Bech32 code (Samuel Dobson)
5599813b80e53a1539c66625b4320ab1b4fb4848 Add lots of comments to Bech32 (Samuel Dobson)
2eb5792ec7bbeaf7138420b6c85c5cd0a0404946 Add release notes for validateaddress Bech32 error detection (MeshCollider)
42d6a029e57a32f2d1d829ff7718b6d40d58b9d1 Refactor and add more tests for validateaddress (Samuel Dobson)
c4979f77c1264f0099d1dfa278b1d9c18340b5f9 Add boost tests for bech32 error detection (MeshCollider)
02a7bdee429ae307a5e57832727fed789e2e04fb Add error_locations to validateaddress RPC (Samuel Dobson)
b62b67e06cc406fdad68da4c091168fb5f11c1d4 Add Bech32 error location function (Samuel Dobson)
0b06e720c0182dee8b560d2e8d3891b036f63ea7 More detailed error checking for base58 addresses (Samuel Dobson)

Pull request description:

  Addresses (partially) #16779 - no GUI change in this PR

  Adds a LocateError function the bech32 library, which is then called by `validateaddress` RPC, (and then eventually from a GUI tool too, future work). I think modifying validateaddress is nicer than adding a separate RPC for this.
  Includes tests.

  Based on https://github.com/sipa/bech32/blob/master/ecc/javascript/bech32_ecc.js
  Credit to sipa for that code

ACKs for top commit:
  laanwj:
    Code review and manually tested ACK 88cc4810926e4f5af6757ee1b0eed61abda3d746
  ryanofsky:
    Code review ACK 88cc4810926e4f5af6757ee1b0eed61abda3d746 with caveat that I only checked the new `LocateErrors` code to try to verify it didn't have unsafe or unexpected operations or loop forever or crash. Did not try to verify behavior corresponds to the spec. In the worst case bugs here should just affect error messages not actual decoding of addresses so this seemed ok.
  w0xlt:
    tACK 88cc481

Tree-SHA512: 9c7fe9745bc7527f80a30bd4c1e3034e16b96a02cc7f6c268f91bfad08a6965a8064fe44230aa3f87e4fa3c938f662ff4446bc682c83cb48c1a3f95cf4186688

1 files changed, 58 insertions, 41 deletions

diff --git a/test/functional/rpc_invalid_address_message.py b/test/functional/rpc_invalid_address_message.py
index 8f9b2c3312..2567564f15 100755
--- a/test/functional/rpc_invalid_address_message.py
+++ b/test/functional/rpc_invalid_address_message.py
@@ -12,79 +12,96 @@ from test_framework.util import (
 )
 
 BECH32_VALID = 'bcrt1qtmp74ayg7p24uslctssvjm06q5phz4yrxucgnv'
+BECH32_VALID_CAPITALS = 'BCRT1QPLMTZKC2XHARPPZDLNPAQL78RSHJ68U33RAH7R'
+BECH32_VALID_MULTISIG = 'bcrt1qdg3myrgvzw7ml9q0ejxhlkyxm7vl9r56yzkfgvzclrf4hkpx9yfqhpsuks'
+
 BECH32_INVALID_BECH32 = 'bcrt1p0xlxvlhemja6c4dqv22uapctqupfhlxm9h8z3k2e72q4k9hcz7vqdmchcc'
 BECH32_INVALID_BECH32M = 'bcrt1qw508d6qejxtdg4y5r3zarvary0c5xw7k35mrzd'
 BECH32_INVALID_VERSION = 'bcrt130xlxvlhemja6c4dqv22uapctqupfhlxm9h8z3k2e72q4k9hcz7vqynjegk'
 BECH32_INVALID_SIZE = 'bcrt1s0xlxvlhemja6c4dqv22uapctqupfhlxm9h8z3k2e72q4k9hcz7v8n0nx0muaewav25430mtr'
 BECH32_INVALID_V0_SIZE = 'bcrt1qw508d6qejxtdg4y5r3zarvary0c5xw7kqqq5k3my'
 BECH32_INVALID_PREFIX = 'bc1pw508d6qejxtdg4y5r3zarvary0c5xw7kw508d6qejxtdg4y5r3zarvary0c5xw7k7grplx'
+BECH32_TOO_LONG = 'bcrt1q049edschfnwystcqnsvyfpj23mpsg3jcedq9xv049edschfnwystcqnsvyfpj23mpsg3jcedq9xv049edschfnwystcqnsvyfpj23m'
+BECH32_ONE_ERROR = 'bcrt1q049edschfnwystcqnsvyfpj23mpsg3jcedq9xv'
+BECH32_ONE_ERROR_CAPITALS = 'BCRT1QPLMTZKC2XHARPPZDLNPAQL78RSHJ68U32RAH7R'
+BECH32_TWO_ERRORS = 'bcrt1qax9suht3qv95sw33xavx8crpxduefdrsvgsklu' # should be bcrt1qax9suht3qv95sw33wavx8crpxduefdrsvgsklx
+BECH32_NO_SEPARATOR = 'bcrtq049ldschfnwystcqnsvyfpj23mpsg3jcedq9xv'
+BECH32_INVALID_CHAR = 'bcrt1q04oldschfnwystcqnsvyfpj23mpsg3jcedq9xv'
+BECH32_MULTISIG_TWO_ERRORS = 'bcrt1qdg3myrgvzw7ml8q0ejxhlkyxn7vl9r56yzkfgvzclrf4hkpx9yfqhpsuks'
+BECH32_WRONG_VERSION = 'bcrt1ptmp74ayg7p24uslctssvjm06q5phz4yrxucgnv'
 
 BASE58_VALID = 'mipcBbFg9gMiCh81Kj8tqqdgoZub1ZJRfn'
 BASE58_INVALID_PREFIX = '17VZNX1SN5NtKa8UQFxwQbFeFc3iqRYhem'
+BASE58_INVALID_CHECKSUM = 'mipcBbFg9gMiCh81Kj8tqqdgoZub1ZJJfn'
+BASE58_INVALID_LENGTH = '2VKf7XKMrp4bVNVmuRbyCewkP8FhGLP2E54LHDPakr9Sq5mtU2'
 
 INVALID_ADDRESS = 'asfah14i8fajz0123f'
+INVALID_ADDRESS_2 = '1q049ldschfnwystcqnsvyfpj23mpsg3jcedq9xv'
 
 class InvalidAddressErrorMessageTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
-    def test_validateaddress(self):
-        node = self.nodes[0]
-
-        # Bech32
-        info = node.validateaddress(BECH32_INVALID_SIZE)
-        assert not info['isvalid']
-        assert_equal(info['error'], 'Invalid Bech32 address data size')
-
-        info = node.validateaddress(BECH32_INVALID_PREFIX)
-        assert not info['isvalid']
-        assert_equal(info['error'], 'Invalid prefix for Bech32 address')
-
-        info = node.validateaddress(BECH32_INVALID_BECH32)
-        assert not info['isvalid']
-        assert_equal(info['error'], 'Version 1+ witness address must use Bech32m checksum')
-
-        info = node.validateaddress(BECH32_INVALID_BECH32M)
-        assert not info['isvalid']
-        assert_equal(info['error'], 'Version 0 witness address must use Bech32 checksum')
-
-        info = node.validateaddress(BECH32_INVALID_V0_SIZE)
-        assert not info['isvalid']
-        assert_equal(info['error'], 'Invalid Bech32 v0 address data size')
-
-        info = node.validateaddress(BECH32_VALID)
+    def check_valid(self, addr):
+        info = self.nodes[0].validateaddress(addr)
         assert info['isvalid']
         assert 'error' not in info
+        assert 'error_locations' not in info
 
-        info = node.validateaddress(BECH32_INVALID_VERSION)
-        assert not info['isvalid']
-        assert_equal(info['error'], 'Invalid Bech32 address witness version')
-
-        # Base58
-        info = node.validateaddress(BASE58_INVALID_PREFIX)
-        assert not info['isvalid']
-        assert_equal(info['error'], 'Invalid prefix for Base58-encoded address')
+    def check_invalid(self, addr, error_str, error_locations=None):
+        res = self.nodes[0].validateaddress(addr)
+        assert not res['isvalid']
+        assert_equal(res['error'], error_str)
+        if error_locations:
+            assert_equal(res['error_locations'], error_locations)
+        else:
+            assert_equal(res['error_locations'], [])
 
-        info = node.validateaddress(BASE58_VALID)
-        assert info['isvalid']
-        assert 'error' not in info
+    def test_validateaddress(self):
+        # Invalid Bech32
+        self.check_invalid(BECH32_INVALID_SIZE, 'Invalid Bech32 address data size')
+        self.check_invalid(BECH32_INVALID_PREFIX, 'Invalid HRP or Base58 character in address')
+        self.check_invalid(BECH32_INVALID_BECH32, 'Version 1+ witness address must use Bech32m checksum')
+        self.check_invalid(BECH32_INVALID_BECH32M, 'Version 0 witness address must use Bech32 checksum')
+        self.check_invalid(BECH32_INVALID_VERSION, 'Invalid Bech32 address witness version')
+        self.check_invalid(BECH32_INVALID_V0_SIZE, 'Invalid Bech32 v0 address data size')
+        self.check_invalid(BECH32_TOO_LONG, 'Bech32 string too long', list(range(90, 108)))
+        self.check_invalid(BECH32_ONE_ERROR, 'Invalid checksum', [9])
+        self.check_invalid(BECH32_TWO_ERRORS, 'Invalid checksum', [22, 43])
+        self.check_invalid(BECH32_ONE_ERROR_CAPITALS, 'Invalid checksum', [38])
+        self.check_invalid(BECH32_NO_SEPARATOR, 'Missing separator')
+        self.check_invalid(BECH32_INVALID_CHAR, 'Invalid Base 32 character', [8])
+        self.check_invalid(BECH32_MULTISIG_TWO_ERRORS, 'Invalid checksum', [19, 30])
+        self.check_invalid(BECH32_WRONG_VERSION, 'Invalid checksum', [5])
+
+        # Valid Bech32
+        self.check_valid(BECH32_VALID)
+        self.check_valid(BECH32_VALID_CAPITALS)
+        self.check_valid(BECH32_VALID_MULTISIG)
+
+        # Invalid Base58
+        self.check_invalid(BASE58_INVALID_PREFIX, 'Invalid prefix for Base58-encoded address')
+        self.check_invalid(BASE58_INVALID_CHECKSUM, 'Invalid checksum or length of Base58 address')
+        self.check_invalid(BASE58_INVALID_LENGTH, 'Invalid checksum or length of Base58 address')
+
+        # Valid Base58
+        self.check_valid(BASE58_VALID)
 
         # Invalid address format
-        info = node.validateaddress(INVALID_ADDRESS)
-        assert not info['isvalid']
-        assert_equal(info['error'], 'Invalid address format')
+        self.check_invalid(INVALID_ADDRESS, 'Invalid HRP or Base58 character in address')
+        self.check_invalid(INVALID_ADDRESS_2, 'Invalid HRP or Base58 character in address')
 
     def test_getaddressinfo(self):
         node = self.nodes[0]
 
         assert_raises_rpc_error(-5, "Invalid Bech32 address data size", node.getaddressinfo, BECH32_INVALID_SIZE)
 
-        assert_raises_rpc_error(-5, "Invalid prefix for Bech32 address", node.getaddressinfo, BECH32_INVALID_PREFIX)
+        assert_raises_rpc_error(-5, "Invalid HRP or Base58 character in address", node.getaddressinfo, BECH32_INVALID_PREFIX)
 
         assert_raises_rpc_error(-5, "Invalid prefix for Base58-encoded address", node.getaddressinfo, BASE58_INVALID_PREFIX)
 
-        assert_raises_rpc_error(-5, "Invalid address format", node.getaddressinfo, INVALID_ADDRESS)
+        assert_raises_rpc_error(-5, "Invalid HRP or Base58 character in address", node.getaddressinfo, INVALID_ADDRESS)
 
     def run_test(self):
         self.test_validateaddress()