Merge bitcoin/bitcoin#24149: Signing support for Miniscript Descriptors

6c7a17a8e0eec377f83ed1399f003ae70b898270 psbt: support externally provided preimages for Miniscript satisfaction (Antoine Poinsot)
840a396029316896beda46600aec3c1af09a899c qa: add a "smart" Miniscript fuzz target (Antoine Poinsot)
17e3547241d593bc92c5c6b36c54284d9d9f3feb qa: add a fuzz target generating random nodes from a binary encoding (Antoine Poinsot)
611e12502a5887ffb751bb92fadaa334d484824b qa: functional test Miniscript signing with key and timelocks (Antoine Poinsot)
d57b7f2021d2369f6e88cdf0f562aab27c51beaf refactor: make descriptors in Miniscript functional test more readable (Antoine Poinsot)
0a8fc9e200b5018c1efd6f9126eb405ca0beeea3 wallet: check solvability using descriptor in AvailableCoins (Antoine Poinsot)
560e62b1e221832ae99ff8684559a7b8f9df84a7 script/sign: signing support for Miniscripts with hash preimage challenges (Antoine Poinsot)
a2f81b6a8f1ff3b0750711409c7538812a52ef40 script/sign: signing support for Miniscript with timelocks (Antoine Poinsot)
61c6d1a8440db09c44d7fd367a6f2c641ea93d40 script/sign: basic signing support for Miniscript descriptors (Antoine Poinsot)
4242c1c52127df3a24be0c15b88d4fc463af04fc Align 'e' property of or_d and andor with website spec (Pieter Wuille)
f5deb417804b9f267830bd40177677987df4526d Various additional explanations of the satisfaction logic from Pieter (Pieter Wuille)
22c5b00345063bdeb8b6d3da8b5692d18f92bfb7 miniscript: satisfaction support (Antoine Poinsot)

Pull request description:

  This makes the Miniscript descriptors solvable.

  Note this introduces signing support for much more complex scripts than the wallet was previously able to solve, and the whole tooling isn't provided for a complete Miniscript integration in the wallet. Particularly, the PSBT<->Miniscript integration isn't entirely covered in this PR.

ACKs for top commit:
  achow101:
    ACK 6c7a17a8e0eec377f83ed1399f003ae70b898270
  sipa:
    utACK 6c7a17a8e0eec377f83ed1399f003ae70b898270 (to the extent that it's not my own code).

Tree-SHA512: a71ec002aaf66bd429012caa338fc58384067bcd2f453a46e21d381ed1bacc8e57afb9db57c0fb4bf40de43b30808815e9ebc0ae1fbd9e61df0e7b91a17771cc

1 files changed, 206 insertions, 5 deletions

diff --git a/test/functional/wallet_miniscript.py b/test/functional/wallet_miniscript.py
index cefcaf4dc7..7bc3424bf4 100755
--- a/test/functional/wallet_miniscript.py
+++ b/test/functional/wallet_miniscript.py
@@ -5,19 +5,137 @@
 """Test Miniscript descriptors integration in the wallet."""
 
 from test_framework.descriptors import descsum_create
+from test_framework.psbt import PSBT, PSBT_IN_SHA256
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
 
+TPRVS = [
+    "tprv8ZgxMBicQKsPerQj6m35no46amfKQdjY7AhLnmatHYXs8S4MTgeZYkWAn4edSGwwL3vkSiiGqSZQrmy5D3P5gBoqgvYP2fCUpBwbKTMTAkL",
+    "tprv8ZgxMBicQKsPd3cbrKjE5GKKJLDEidhtzSSmPVtSPyoHQGL2LZw49yt9foZsN9BeiC5VqRaESUSDV2PS9w7zAVBSK6EQH3CZW9sMKxSKDwD",
+    "tprv8iF7W37EHnVEtDr9EFeyFjQJFL6SfGby2AnZ2vQARxTQHQXy9tdzZvBBVp8a19e5vXhskczLkJ1AZjqgScqWL4FpmXVp8LLjiorcrFK63Sr",
+]
+TPUBS = [
+    "tpubD6NzVbkrYhZ4YPAbyf6urxqqnmJF79PzQtyERAmvkSVS9fweCTjxjDh22Z5St9fGb1a5DUCv8G27nYupKP1Ctr1pkamJossoetzws1moNRn",
+    "tpubD6NzVbkrYhZ4YMQC15JS7QcrsAyfGrGiykweqMmPxTkEVScu7vCZLNpPXW1XphHwzsgmqdHWDQAfucbM72EEB1ZEyfgZxYvkZjYVXx1xS9p",
+    "tpubD6NzVbkrYhZ4YU9vM1s53UhD75UyJatx8EMzMZ3VUjR2FciNfLLkAw6a4pWACChzobTseNqdWk4G7ZdBqRDLtLSACKykTScmqibb1ZrCvJu",
+    "tpubD6NzVbkrYhZ4XRMcMFMMFvzVt6jaDAtjZhD7JLwdPdMm9xa76DnxYYP7w9TZGJDVFkek3ArwVsuacheqqPog8TH5iBCX1wuig8PLXim4n9a",
+    "tpubD6NzVbkrYhZ4WsqRzDmkL82SWcu42JzUvKWzrJHQ8EC2vEHRHkXj1De93sD3biLrKd8XGnamXURGjMbYavbszVDXpjXV2cGUERucLJkE6cy",
+    "tpubDEFLeBkKTm8aiYkySz8hXAXPVnPSfxMi7Fxhg9sejUrkwJuRWvPdLEiXjTDbhGbjLKCZUDUUibLxTnK5UP1q7qYrSnPqnNe7M8mvAW1STcc",
+]
+PUBKEYS = [
+    "02aebf2d10b040eb936a6f02f44ee82f8b34f5c1ccb20ff3949c2b28206b7c1068",
+    "030f64b922aee2fd597f104bc6cb3b670f1ca2c6c49b1071a1a6c010575d94fe5a",
+    "02abe475b199ec3d62fa576faee16a334fdb86ffb26dce75becebaaedf328ac3fe",
+    "0314f3dc33595b0d016bb522f6fe3a67680723d842c1b9b8ae6b59fdd8ab5cccb4",
+    "025eba3305bd3c829e4e1551aac7358e4178832c739e4fc4729effe428de0398ab",
+    "029ffbe722b147f3035c87cb1c60b9a5947dd49c774cc31e94773478711a929ac0",
+    "0211c7b2e18b6fd330f322de087da62da92ae2ae3d0b7cec7e616479cce175f183",
+]
+
 MINISCRIPTS = [
     # One of two keys
-    "or_b(pk(tpubD6NzVbkrYhZ4XRMcMFMMFvzVt6jaDAtjZhD7JLwdPdMm9xa76DnxYYP7w9TZGJDVFkek3ArwVsuacheqqPog8TH5iBCX1wuig8PLXim4n9a/*),s:pk(tpubD6NzVbkrYhZ4WsqRzDmkL82SWcu42JzUvKWzrJHQ8EC2vEHRHkXj1De93sD3biLrKd8XGnamXURGjMbYavbszVDXpjXV2cGUERucLJkE6cy/*))",
+    f"or_b(pk({TPUBS[0]}/*),s:pk({TPUBS[1]}/*))",
     # A script similar (same spending policy) to BOLT3's offered HTLC (with anchor outputs)
-    "or_d(pk(tpubD6NzVbkrYhZ4XRMcMFMMFvzVt6jaDAtjZhD7JLwdPdMm9xa76DnxYYP7w9TZGJDVFkek3ArwVsuacheqqPog8TH5iBCX1wuig8PLXim4n9a/*),and_v(and_v(v:pk(tpubD6NzVbkrYhZ4WsqRzDmkL82SWcu42JzUvKWzrJHQ8EC2vEHRHkXj1De93sD3biLrKd8XGnamXURGjMbYavbszVDXpjXV2cGUERucLJkE6cy/*),or_c(pk(tpubD6NzVbkrYhZ4YNwtTWrKRJQzQX3PjPKeUQg1gYh1hiLMkk1cw8SRLgB1yb7JzE8bHKNt6EcZXkJ6AqpCZL1aaRSjnG36mLgbQvJZBNsjWnG/*),v:hash160(7f999c905d5e35cefd0a37673f746eb13fba3640))),older(1)))",
+    f"or_d(pk({TPUBS[0]}/*),and_v(and_v(v:pk({TPUBS[1]}/*),or_c(pk({TPUBS[2]}/*),v:hash160(7f999c905d5e35cefd0a37673f746eb13fba3640))),older(1)))",
     # A Revault Unvault policy with the older() replaced by an after()
-    "andor(multi(2,tpubD6NzVbkrYhZ4YMQC15JS7QcrsAyfGrGiykweqMmPxTkEVScu7vCZLNpPXW1XphHwzsgmqdHWDQAfucbM72EEB1ZEyfgZxYvkZjYVXx1xS9p/*,tpubD6NzVbkrYhZ4WkCyc7E3z6g6NkypHMiecnwc4DpWHTPqFdteRGkEKukdrSSyJGNnGrHNMfy4BCw2UXo5soYRCtCDDfy4q8pc8oyB7RgTFv8/*),and_v(v:multi(4,030f64b922aee2fd597f104bc6cb3b670f1ca2c6c49b1071a1a6c010575d94fe5a,02abe475b199ec3d62fa576faee16a334fdb86ffb26dce75becebaaedf328ac3fe,0314f3dc33595b0d016bb522f6fe3a67680723d842c1b9b8ae6b59fdd8ab5cccb4,025eba3305bd3c829e4e1551aac7358e4178832c739e4fc4729effe428de0398ab),after(424242)),thresh(4,pkh(tpubD6NzVbkrYhZ4YVrNggiT2ptVHwnFbLBqDkCtV5HkxR4WtcRLAQReKTkqZGNcV6GE7cQsmpBzzSzhk16DUwB1gn1L7ZPnJF2dnNePP1uMBCY/*),a:pkh(tpubD6NzVbkrYhZ4YU9vM1s53UhD75UyJatx8EMzMZ3VUjR2FciNfLLkAw6a4pWACChzobTseNqdWk4G7ZdBqRDLtLSACKykTScmqibb1ZrCvJu/*),a:pkh(tpubD6NzVbkrYhZ4YUHcFfuH9iEBLiH8CBRJTpS7X3qjHmh82m1KCNbzs6w9gyK8oWHSZmKHWcakAXCGfbKg6xoCvKzQCWAHyxaC7QcWfmzyBf4/*),a:pkh(tpubD6NzVbkrYhZ4XXEmQtS3sgxpJbMyMg4McqRR1Af6ULzyrTRnhwjyr1etPD7svap9oFtJf4MM72brUb5o7uvF2Jyszc5c1t836fJW7SX2e8D/*)))",
+    f"andor(multi(2,{TPUBS[0]}/*,{TPUBS[1]}/*),and_v(v:multi(4,{PUBKEYS[0]},{PUBKEYS[1]},{PUBKEYS[2]},{PUBKEYS[3]}),after(424242)),thresh(4,pkh({TPUBS[2]}/*),a:pkh({TPUBS[3]}/*),a:pkh({TPUBS[4]}/*),a:pkh({TPUBS[5]}/*)))",
     # Liquid-like federated pegin with emergency recovery keys
-    "or_i(and_b(pk(029ffbe722b147f3035c87cb1c60b9a5947dd49c774cc31e94773478711a929ac0),a:and_b(pk(025f05815e3a1a8a83bfbb03ce016c9a2ee31066b98f567f6227df1d76ec4bd143),a:and_b(pk(025625f41e4a065efc06d5019cbbd56fe8c07595af1231e7cbc03fafb87ebb71ec),a:and_b(pk(02a27c8b850a00f67da3499b60562673dcf5fdfb82b7e17652a7ac54416812aefd),s:pk(03e618ec5f384d6e19ca9ebdb8e2119e5bef978285076828ce054e55c4daf473e2))))),and_v(v:thresh(2,pkh(tpubD6NzVbkrYhZ4YK67cd5fDe4fBVmGB2waTDrAt1q4ey9HPq9veHjWkw3VpbaCHCcWozjkhgAkWpFrxuPMUrmXVrLHMfEJ9auoZA6AS1g3grC/*),a:pkh(033841045a531e1adf9910a6ec279589a90b3b8a904ee64ffd692bd08a8996c1aa),a:pkh(02aebf2d10b040eb936a6f02f44ee82f8b34f5c1ccb20ff3949c2b28206b7c1068)),older(4209713)))",
+    f"or_i(and_b(pk({PUBKEYS[0]}),a:and_b(pk({PUBKEYS[1]}),a:and_b(pk({PUBKEYS[2]}),a:and_b(pk({PUBKEYS[3]}),s:pk({PUBKEYS[4]}))))),and_v(v:thresh(2,pkh({TPUBS[0]}/*),a:pkh({PUBKEYS[5]}),a:pkh({PUBKEYS[6]})),older(4209713)))",
+]
+
+MINISCRIPTS_PRIV = [
+    # One of two keys, of which one private key is known
+    {
+        "ms": f"or_i(pk({TPRVS[0]}/*),pk({TPUBS[0]}/*))",
+        "sequence": None,
+        "locktime": None,
+        "sigs_count": 1,
+        "stack_size": 3,
+    },
+    # A more complex policy, that can't be satisfied through the first branch (need for a preimage)
+    {
+        "ms": f"andor(ndv:older(2),and_v(v:pk({TPRVS[0]}),sha256(2a8ce30189b2ec3200b47aeb4feaac8fcad7c0ba170389729f4898b0b7933bcb)),and_v(v:pkh({TPRVS[1]}),pk({TPRVS[2]}/*)))",
+        "sequence": 2,
+        "locktime": None,
+        "sigs_count": 3,
+        "stack_size": 5,
+    },
+    # The same policy but we provide the preimage. This path will be chosen as it's a smaller witness.
+    {
+        "ms": f"andor(ndv:older(2),and_v(v:pk({TPRVS[0]}),sha256(61e33e9dbfefc45f6a194187684d278f789fd4d5e207a357e79971b6519a8b12)),and_v(v:pkh({TPRVS[1]}),pk({TPRVS[2]}/*)))",
+        "sequence": 2,
+        "locktime": None,
+        "sigs_count": 3,
+        "stack_size": 4,
+        "sha256_preimages": {
+            "61e33e9dbfefc45f6a194187684d278f789fd4d5e207a357e79971b6519a8b12": "e8774f330f5f330c23e8bbefc5595cb87009ddb7ac3b8deaaa8e9e41702d919c"
+        },
+    },
+    # Signature with a relative timelock
+    {
+        "ms": f"and_v(v:older(2),pk({TPRVS[0]}/*))",
+        "sequence": 2,
+        "locktime": None,
+        "sigs_count": 1,
+        "stack_size": 2,
+    },
+    # Signature with an absolute timelock
+    {
+        "ms": f"and_v(v:after(20),pk({TPRVS[0]}/*))",
+        "sequence": None,
+        "locktime": 20,
+        "sigs_count": 1,
+        "stack_size": 2,
+    },
+    # Signature with both
+    {
+        "ms": f"and_v(v:older(4),and_v(v:after(30),pk({TPRVS[0]}/*)))",
+        "sequence": 4,
+        "locktime": 30,
+        "sigs_count": 1,
+        "stack_size": 2,
+    },
+    # We have one key on each branch; Core signs both (can't finalize)
+    {
+        "ms": f"c:andor(pk({TPRVS[0]}/*),pk_k({TPUBS[0]}),and_v(v:pk({TPRVS[1]}),pk_k({TPUBS[1]})))",
+        "sequence": None,
+        "locktime": None,
+        "sigs_count": 2,
+        "stack_size": None,
+    },
+    # We have all the keys, wallet selects the timeout path to sign since it's smaller and sequence is set
+    {
+        "ms": f"andor(pk({TPRVS[0]}/*),pk({TPRVS[2]}),and_v(v:pk({TPRVS[1]}),older(10)))",
+        "sequence": 10,
+        "locktime": None,
+        "sigs_count": 3,
+        "stack_size": 3,
+    },
+    # We have all the keys, wallet selects the primary path to sign unconditionally since nsequence wasn't set to be valid for timeout path
+    {
+        "ms": f"andor(pk({TPRVS[0]}/*),pk({TPRVS[2]}),and_v(v:pkh({TPRVS[1]}),older(10)))",
+        "sequence": None,
+        "locktime": None,
+        "sigs_count": 3,
+        "stack_size": 3,
+    },
+    # Finalizes to the smallest valid witness, regardless of sequence
+    {
+        "ms": f"or_d(pk({TPRVS[0]}/*),and_v(v:pk({TPRVS[1]}),and_v(v:pk({TPRVS[2]}),older(10))))",
+        "sequence": 12,
+        "locktime": None,
+        "sigs_count": 3,
+        "stack_size": 2,
+    },
+    # Liquid-like federated pegin with emergency recovery privkeys
+    {
+        "ms": f"or_i(and_b(pk({TPUBS[0]}/*),a:and_b(pk({TPUBS[1]}),a:and_b(pk({TPUBS[2]}),a:and_b(pk({TPUBS[3]}),s:pk({PUBKEYS[0]}))))),and_v(v:thresh(2,pkh({TPRVS[0]}),a:pkh({TPRVS[1]}),a:pkh({TPUBS[4]})),older(42)))",
+        "sequence": 42,
+        "locktime": None,
+        "sigs_count": 2,
+        "stack_size": 8,
+    },
 ]
 
 
@@ -62,7 +180,77 @@ class WalletMiniscriptTest(BitcoinTestFramework):
             lambda: len(self.ms_wo_wallet.listunspent(minconf=0, addresses=[addr])) == 1
         )
         utxo = self.ms_wo_wallet.listunspent(minconf=0, addresses=[addr])[0]
-        assert utxo["txid"] == txid and not utxo["solvable"]  # No satisfaction logic (yet)
+        assert utxo["txid"] == txid and utxo["solvable"]
+
+    def signing_test(
+        self, ms, sequence, locktime, sigs_count, stack_size, sha256_preimages
+    ):
+        self.log.info(f"Importing private Miniscript '{ms}'")
+        desc = descsum_create(f"wsh({ms})")
+        res = self.ms_sig_wallet.importdescriptors(
+            [
+                {
+                    "desc": desc,
+                    "active": True,
+                    "range": 0,
+                    "next_index": 0,
+                    "timestamp": "now",
+                }
+            ]
+        )
+        assert res[0]["success"], res
+
+        self.log.info("Generating an address for it and testing it detects funds")
+        addr = self.ms_sig_wallet.getnewaddress()
+        txid = self.funder.sendtoaddress(addr, 0.01)
+        self.wait_until(lambda: txid in self.funder.getrawmempool())
+        self.funder.generatetoaddress(1, self.funder.getnewaddress())
+        utxo = self.ms_sig_wallet.listunspent(addresses=[addr])[0]
+        assert txid == utxo["txid"] and utxo["solvable"]
+
+        self.log.info("Creating a transaction spending these funds")
+        dest_addr = self.funder.getnewaddress()
+        seq = sequence if sequence is not None else 0xFFFFFFFF - 2
+        lt = locktime if locktime is not None else 0
+        psbt = self.ms_sig_wallet.createpsbt(
+            [
+                {
+                    "txid": txid,
+                    "vout": utxo["vout"],
+                    "sequence": seq,
+                }
+            ],
+            [{dest_addr: 0.009}],
+            lt,
+        )
+
+        self.log.info("Signing it and checking the satisfaction.")
+        if sha256_preimages is not None:
+            psbt = PSBT.from_base64(psbt)
+            for (h, preimage) in sha256_preimages.items():
+                k = PSBT_IN_SHA256.to_bytes(1, "big") + bytes.fromhex(h)
+                psbt.i[0].map[k] = bytes.fromhex(preimage)
+            psbt = psbt.to_base64()
+        res = self.ms_sig_wallet.walletprocesspsbt(psbt=psbt, finalize=False)
+        psbtin = self.nodes[0].rpc.decodepsbt(res["psbt"])["inputs"][0]
+        assert len(psbtin["partial_signatures"]) == sigs_count
+        res = self.ms_sig_wallet.finalizepsbt(res["psbt"])
+        assert res["complete"] == (stack_size is not None)
+
+        if stack_size is not None:
+            txin = self.nodes[0].rpc.decoderawtransaction(res["hex"])["vin"][0]
+            assert len(txin["txinwitness"]) == stack_size, txin["txinwitness"]
+            self.log.info("Broadcasting the transaction.")
+            # If necessary, satisfy a relative timelock
+            if sequence is not None:
+                self.funder.generatetoaddress(sequence, self.funder.getnewaddress())
+            # If necessary, satisfy an absolute timelock
+            height = self.funder.getblockcount()
+            if locktime is not None and height < locktime:
+                self.funder.generatetoaddress(
+                    locktime - height, self.funder.getnewaddress()
+                )
+            self.ms_sig_wallet.sendrawtransaction(res["hex"])
 
     def run_test(self):
         self.log.info("Making a descriptor wallet")
@@ -71,6 +259,8 @@ class WalletMiniscriptTest(BitcoinTestFramework):
             wallet_name="ms_wo", descriptors=True, disable_private_keys=True
         )
         self.ms_wo_wallet = self.nodes[0].get_wallet_rpc("ms_wo")
+        self.nodes[0].createwallet(wallet_name="ms_sig", descriptors=True)
+        self.ms_sig_wallet = self.nodes[0].get_wallet_rpc("ms_sig")
 
         # Sanity check we wouldn't let an insane Miniscript descriptor in
         res = self.ms_wo_wallet.importdescriptors(
@@ -91,6 +281,17 @@ class WalletMiniscriptTest(BitcoinTestFramework):
         for ms in MINISCRIPTS:
             self.watchonly_test(ms)
 
+        # Test we can sign for any Miniscript.
+        for ms in MINISCRIPTS_PRIV:
+            self.signing_test(
+                ms["ms"],
+                ms["sequence"],
+                ms["locktime"],
+                ms["sigs_count"],
+                ms["stack_size"],
+                ms.get("sha256_preimages"),
+            )
+
 
 if __name__ == "__main__":
     WalletMiniscriptTest().main()