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bitcoin/src/script/descriptor.cpp
glozow f93d5553d1
Merge bitcoin/bitcoin#22838: descriptors: Be able to specify change and receiving in a single descriptor string 
a0abcbd382 doc: Mention multipath specifier (Ava Chow)
0019f61fc5 tests: Test importing of multipath descriptors (Ava Chow)
f97d5c137d wallet, rpc: Allow importdescriptors to import multipath descriptors (Ava Chow)
32dcbca3fb rpc: Allow importmulti to import multipath descriptors correctly (Ava Chow)
64dfe3ce4b wallet: Move internal to be per key when importing (Ava Chow)
1692245525 tests: Multipath descriptors for scantxoutset and deriveaddresses (Ava Chow)
cddc0ba9a9 rpc: Have deriveaddresses derive receiving and change (Ava Chow)
360456cd22 tests: Multipath descriptors for getdescriptorinfo (Ava Chow)
a90eee444c tests: Add unit tests for multipath descriptors (Ava Chow)
1bbf46e2da descriptors: Change Parse to return vector of descriptors (Ava Chow)
0d640c6f02 descriptors: Have ParseKeypath handle multipath specifiers (Ava Chow)
a5f39b1034 descriptors: Change ParseScript to return vector of descriptors (Ava Chow)
0d55deae15 descriptors: Add DescriptorImpl::Clone (Ava Chow)
7e86541f72 descriptors: Add PubkeyProvider::Clone (Ava Chow)

Pull request description:

  It is convenient to have a descriptor which specifies both receiving and change addresses in a single string. However, as discussed in https://github.com/bitcoin/bitcoin/issues/17190#issuecomment-895515768, it is not feasible to use a generic multipath specification like BIP 88 due to combinatorial blow up and that it would result in unexpected descriptors.

  To resolve that problem, this PR proposes a targeted solution which allows only a single pair of 2 derivation indexes to be inserted in the place of a single derivation index. So instead of two descriptor `wpkh(xpub.../0/0/*)` and `wpkh(xpub.../0/1/*)` to represent receive and change addresses, this could be written as `wpkh(xpub.../0/<0;1>/*)`. The multipath specifier is of the form `<NUM;NUM>`. Each `NUM` can have its own hardened specifier, e.g. `<0;1h>` is valid. The multipath specifier can also only appear in one path index in the derivation path.

  This results in the parser returning two descriptors. The first descriptor uses the first `NUM` in all pairs present, and the second uses the second `NUM`. In our implementation, if a multipath descriptor is not provided, a pair is still returned, but the second element is just `nullptr`.

  The wallet will not output the multipath descriptors (yet). Furthermore, when a multipath descriptor is imported, it is expanded to the two descriptors and each imported on its own, with the second descriptor being implicitly for internal (change) addresses. There is no change to how the wallet stores or outputs descriptors (yet).

  Note that the path specifier is different from what was proposed. It uses angle brackets and the semicolon because these are unused characters available in the character set and I wanted to avoid conflicts with characters already in use in descriptors.

  Closes #17190

ACKs for top commit:
  darosior:
    re-ACK a0abcbd382
  mjdietzx:
    reACK a0abcbd382
  pythcoiner:
    reACK a0abcbd
  furszy:
    Code review ACK a0abcbd
  glozow:
    light code review ACK a0abcbd382

Tree-SHA512: 84ea40b3fd1b762194acd021cae018c2f09b98e595f5e87de5c832c265cfe8a6d0bc4dae25785392fa90db0f6301ddf9aea787980a29c74f81d04b711ac446c2
2024-08-28 15:56:15 +01:00

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// Copyright (c) 2018-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <script/descriptor.h>
#include <hash.h>
#include <key_io.h>
#include <pubkey.h>
#include <script/miniscript.h>
#include <script/parsing.h>
#include <script/script.h>
#include <script/signingprovider.h>
#include <script/solver.h>
#include <uint256.h>
#include <common/args.h>
#include <span.h>
#include <util/bip32.h>
#include <util/check.h>
#include <util/strencodings.h>
#include <util/vector.h>
#include <algorithm>
#include <memory>
#include <numeric>
#include <optional>
#include <string>
#include <vector>
using util::Split;
namespace {
////////////////////////////////////////////////////////////////////////////
// Checksum //
////////////////////////////////////////////////////////////////////////////
// This section implements a checksum algorithm for descriptors with the
// following properties:
// * Mistakes in a descriptor string are measured in "symbol errors". The higher
// the number of symbol errors, the harder it is to detect:
// * An error substituting a character from 0123456789()[],'/*abcdefgh@:$%{} for
// another in that set always counts as 1 symbol error.
// * Note that hex encoded keys are covered by these characters. Xprvs and
// xpubs use other characters too, but already have their own checksum
// mechanism.
// * Function names like "multi()" use other characters, but mistakes in
// these would generally result in an unparsable descriptor.
// * A case error always counts as 1 symbol error.
// * Any other 1 character substitution error counts as 1 or 2 symbol errors.
// * Any 1 symbol error is always detected.
// * Any 2 or 3 symbol error in a descriptor of up to 49154 characters is always detected.
// * Any 4 symbol error in a descriptor of up to 507 characters is always detected.
// * Any 5 symbol error in a descriptor of up to 77 characters is always detected.
// * Is optimized to minimize the chance a 5 symbol error in a descriptor up to 387 characters is undetected
// * Random errors have a chance of 1 in 2**40 of being undetected.
//
// These properties are achieved by expanding every group of 3 (non checksum) characters into
// 4 GF(32) symbols, over which a cyclic code is defined.
/*
* Interprets c as 8 groups of 5 bits which are the coefficients of a degree 8 polynomial over GF(32),
* multiplies that polynomial by x, computes its remainder modulo a generator, and adds the constant term val.
*
* This generator is G(x) = x^8 + {30}x^7 + {23}x^6 + {15}x^5 + {14}x^4 + {10}x^3 + {6}x^2 + {12}x + {9}.
* It is chosen to define an cyclic error detecting code which is selected by:
* - Starting from all BCH codes over GF(32) of degree 8 and below, which by construction guarantee detecting
* 3 errors in windows up to 19000 symbols.
* - Taking all those generators, and for degree 7 ones, extend them to degree 8 by adding all degree-1 factors.
* - Selecting just the set of generators that guarantee detecting 4 errors in a window of length 512.
* - Selecting one of those with best worst-case behavior for 5 errors in windows of length up to 512.
*
* The generator and the constants to implement it can be verified using this Sage code:
* B = GF(2) # Binary field
* BP.<b> = B[] # Polynomials over the binary field
* F_mod = b**5 + b**3 + 1
* F.<f> = GF(32, modulus=F_mod, repr='int') # GF(32) definition
* FP.<x> = F[] # Polynomials over GF(32)
* E_mod = x**3 + x + F.fetch_int(8)
* E.<e> = F.extension(E_mod) # Extension field definition
* alpha = e**2743 # Choice of an element in extension field
* for p in divisors(E.order() - 1): # Verify alpha has order 32767.
* assert((alpha**p == 1) == (p % 32767 == 0))
* G = lcm([(alpha**i).minpoly() for i in [1056,1057,1058]] + [x + 1])
* print(G) # Print out the generator
* for i in [1,2,4,8,16]: # Print out {1,2,4,8,16}*(G mod x^8), packed in hex integers.
* v = 0
* for coef in reversed((F.fetch_int(i)*(G % x**8)).coefficients(sparse=True)):
* v = v*32 + coef.integer_representation()
* print("0x%x" % v)
*/
uint64_t PolyMod(uint64_t c, int val)
{
uint8_t c0 = c >> 35;
c = ((c & 0x7ffffffff) << 5) ^ val;
if (c0 & 1) c ^= 0xf5dee51989;
if (c0 & 2) c ^= 0xa9fdca3312;
if (c0 & 4) c ^= 0x1bab10e32d;
if (c0 & 8) c ^= 0x3706b1677a;
if (c0 & 16) c ^= 0x644d626ffd;
return c;
}
std::string DescriptorChecksum(const Span<const char>& span)
{
/** A character set designed such that:
* - The most common 'unprotected' descriptor characters (hex, keypaths) are in the first group of 32.
* - Case errors cause an offset that's a multiple of 32.
* - As many alphabetic characters are in the same group (while following the above restrictions).
*
* If p(x) gives the position of a character c in this character set, every group of 3 characters
* (a,b,c) is encoded as the 4 symbols (p(a) & 31, p(b) & 31, p(c) & 31, (p(a) / 32) + 3 * (p(b) / 32) + 9 * (p(c) / 32).
* This means that changes that only affect the lower 5 bits of the position, or only the higher 2 bits, will just
* affect a single symbol.
*
* As a result, within-group-of-32 errors count as 1 symbol, as do cross-group errors that don't affect
* the position within the groups.
*/
static const std::string INPUT_CHARSET =
"0123456789()[],'/*abcdefgh@:$%{}"
"IJKLMNOPQRSTUVWXYZ&+-.;<=>?!^_|~"
"ijklmnopqrstuvwxyzABCDEFGH`#\"\\ ";
/** The character set for the checksum itself (same as bech32). */
static const std::string CHECKSUM_CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l";
uint64_t c = 1;
int cls = 0;
int clscount = 0;
for (auto ch : span) {
auto pos = INPUT_CHARSET.find(ch);
if (pos == std::string::npos) return "";
c = PolyMod(c, pos & 31); // Emit a symbol for the position inside the group, for every character.
cls = cls * 3 + (pos >> 5); // Accumulate the group numbers
if (++clscount == 3) {
// Emit an extra symbol representing the group numbers, for every 3 characters.
c = PolyMod(c, cls);
cls = 0;
clscount = 0;
}
}
if (clscount > 0) c = PolyMod(c, cls);
for (int j = 0; j < 8; ++j) c = PolyMod(c, 0); // Shift further to determine the checksum.
c ^= 1; // Prevent appending zeroes from not affecting the checksum.
std::string ret(8, ' ');
for (int j = 0; j < 8; ++j) ret[j] = CHECKSUM_CHARSET[(c >> (5 * (7 - j))) & 31];
return ret;
}
std::string AddChecksum(const std::string& str) { return str + "#" + DescriptorChecksum(str); }
////////////////////////////////////////////////////////////////////////////
// Internal representation //
////////////////////////////////////////////////////////////////////////////
typedef std::vector<uint32_t> KeyPath;
/** Interface for public key objects in descriptors. */
struct PubkeyProvider
{
protected:
//! Index of this key expression in the descriptor
//! E.g. If this PubkeyProvider is key1 in multi(2, key1, key2, key3), then m_expr_index = 0
uint32_t m_expr_index;
public:
explicit PubkeyProvider(uint32_t exp_index) : m_expr_index(exp_index) {}
virtual ~PubkeyProvider() = default;
/** Compare two public keys represented by this provider.
* Used by the Miniscript descriptors to check for duplicate keys in the script.
*/
bool operator<(PubkeyProvider& other) const {
CPubKey a, b;
SigningProvider dummy;
KeyOriginInfo dummy_info;
GetPubKey(0, dummy, a, dummy_info);
other.GetPubKey(0, dummy, b, dummy_info);
return a < b;
}
/** Derive a public key.
* read_cache is the cache to read keys from (if not nullptr)
* write_cache is the cache to write keys to (if not nullptr)
* Caches are not exclusive but this is not tested. Currently we use them exclusively
*/
virtual bool GetPubKey(int pos, const SigningProvider& arg, CPubKey& key, KeyOriginInfo& info, const DescriptorCache* read_cache = nullptr, DescriptorCache* write_cache = nullptr) const = 0;
/** Whether this represent multiple public keys at different positions. */
virtual bool IsRange() const = 0;
/** Get the size of the generated public key(s) in bytes (33 or 65). */
virtual size_t GetSize() const = 0;
enum class StringType {
PUBLIC,
COMPAT // string calculation that mustn't change over time to stay compatible with previous software versions
};
/** Get the descriptor string form. */
virtual std::string ToString(StringType type=StringType::PUBLIC) const = 0;
/** Get the descriptor string form including private data (if available in arg). */
virtual bool ToPrivateString(const SigningProvider& arg, std::string& out) const = 0;
/** Get the descriptor string form with the xpub at the last hardened derivation,
* and always use h for hardened derivation.
*/
virtual bool ToNormalizedString(const SigningProvider& arg, std::string& out, const DescriptorCache* cache = nullptr) const = 0;
/** Derive a private key, if private data is available in arg. */
virtual bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const = 0;
/** Return the non-extended public key for this PubkeyProvider, if it has one. */
virtual std::optional<CPubKey> GetRootPubKey() const = 0;
/** Return the extended public key for this PubkeyProvider, if it has one. */
virtual std::optional<CExtPubKey> GetRootExtPubKey() const = 0;
/** Make a deep copy of this PubkeyProvider */
virtual std::unique_ptr<PubkeyProvider> Clone() const = 0;
};
class OriginPubkeyProvider final : public PubkeyProvider
{
KeyOriginInfo m_origin;
std::unique_ptr<PubkeyProvider> m_provider;
bool m_apostrophe;
std::string OriginString(StringType type, bool normalized=false) const
{
// If StringType==COMPAT, always use the apostrophe to stay compatible with previous versions
bool use_apostrophe = (!normalized && m_apostrophe) || type == StringType::COMPAT;
return HexStr(m_origin.fingerprint) + FormatHDKeypath(m_origin.path, use_apostrophe);
}
public:
OriginPubkeyProvider(uint32_t exp_index, KeyOriginInfo info, std::unique_ptr<PubkeyProvider> provider, bool apostrophe) : PubkeyProvider(exp_index), m_origin(std::move(info)), m_provider(std::move(provider)), m_apostrophe(apostrophe) {}
bool GetPubKey(int pos, const SigningProvider& arg, CPubKey& key, KeyOriginInfo& info, const DescriptorCache* read_cache = nullptr, DescriptorCache* write_cache = nullptr) const override
{
if (!m_provider->GetPubKey(pos, arg, key, info, read_cache, write_cache)) return false;
std::copy(std::begin(m_origin.fingerprint), std::end(m_origin.fingerprint), info.fingerprint);
info.path.insert(info.path.begin(), m_origin.path.begin(), m_origin.path.end());
return true;
}
bool IsRange() const override { return m_provider->IsRange(); }
size_t GetSize() const override { return m_provider->GetSize(); }
std::string ToString(StringType type) const override { return "[" + OriginString(type) + "]" + m_provider->ToString(type); }
bool ToPrivateString(const SigningProvider& arg, std::string& ret) const override
{
std::string sub;
if (!m_provider->ToPrivateString(arg, sub)) return false;
ret = "[" + OriginString(StringType::PUBLIC) + "]" + std::move(sub);
return true;
}
bool ToNormalizedString(const SigningProvider& arg, std::string& ret, const DescriptorCache* cache) const override
{
std::string sub;
if (!m_provider->ToNormalizedString(arg, sub, cache)) return false;
// If m_provider is a BIP32PubkeyProvider, we may get a string formatted like a OriginPubkeyProvider
// In that case, we need to strip out the leading square bracket and fingerprint from the substring,
// and append that to our own origin string.
if (sub[0] == '[') {
sub = sub.substr(9);
ret = "[" + OriginString(StringType::PUBLIC, /*normalized=*/true) + std::move(sub);
} else {
ret = "[" + OriginString(StringType::PUBLIC, /*normalized=*/true) + "]" + std::move(sub);
}
return true;
}
bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const override
{
return m_provider->GetPrivKey(pos, arg, key);
}
std::optional<CPubKey> GetRootPubKey() const override
{
return m_provider->GetRootPubKey();
}
std::optional<CExtPubKey> GetRootExtPubKey() const override
{
return m_provider->GetRootExtPubKey();
}
std::unique_ptr<PubkeyProvider> Clone() const override
{
return std::make_unique<OriginPubkeyProvider>(m_expr_index, m_origin, m_provider->Clone(), m_apostrophe);
}
};
/** An object representing a parsed constant public key in a descriptor. */
class ConstPubkeyProvider final : public PubkeyProvider
{
CPubKey m_pubkey;
bool m_xonly;
public:
ConstPubkeyProvider(uint32_t exp_index, const CPubKey& pubkey, bool xonly) : PubkeyProvider(exp_index), m_pubkey(pubkey), m_xonly(xonly) {}
bool GetPubKey(int pos, const SigningProvider& arg, CPubKey& key, KeyOriginInfo& info, const DescriptorCache* read_cache = nullptr, DescriptorCache* write_cache = nullptr) const override
{
key = m_pubkey;
info.path.clear();
CKeyID keyid = m_pubkey.GetID();
std::copy(keyid.begin(), keyid.begin() + sizeof(info.fingerprint), info.fingerprint);
return true;
}
bool IsRange() const override { return false; }
size_t GetSize() const override { return m_pubkey.size(); }
std::string ToString(StringType type) const override { return m_xonly ? HexStr(m_pubkey).substr(2) : HexStr(m_pubkey); }
bool ToPrivateString(const SigningProvider& arg, std::string& ret) const override
{
CKey key;
if (m_xonly) {
for (const auto& keyid : XOnlyPubKey(m_pubkey).GetKeyIDs()) {
arg.GetKey(keyid, key);
if (key.IsValid()) break;
}
} else {
arg.GetKey(m_pubkey.GetID(), key);
}
if (!key.IsValid()) return false;
ret = EncodeSecret(key);
return true;
}
bool ToNormalizedString(const SigningProvider& arg, std::string& ret, const DescriptorCache* cache) const override
{
ret = ToString(StringType::PUBLIC);
return true;
}
bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const override
{
return arg.GetKey(m_pubkey.GetID(), key);
}
std::optional<CPubKey> GetRootPubKey() const override
{
return m_pubkey;
}
std::optional<CExtPubKey> GetRootExtPubKey() const override
{
return std::nullopt;
}
std::unique_ptr<PubkeyProvider> Clone() const override
{
return std::make_unique<ConstPubkeyProvider>(m_expr_index, m_pubkey, m_xonly);
}
};
enum class DeriveType {
NO,
UNHARDENED,
HARDENED,
};
/** An object representing a parsed extended public key in a descriptor. */
class BIP32PubkeyProvider final : public PubkeyProvider
{
// Root xpub, path, and final derivation step type being used, if any
CExtPubKey m_root_extkey;
KeyPath m_path;
DeriveType m_derive;
// Whether ' or h is used in harded derivation
bool m_apostrophe;
bool GetExtKey(const SigningProvider& arg, CExtKey& ret) const
{
CKey key;
if (!arg.GetKey(m_root_extkey.pubkey.GetID(), key)) return false;
ret.nDepth = m_root_extkey.nDepth;
std::copy(m_root_extkey.vchFingerprint, m_root_extkey.vchFingerprint + sizeof(ret.vchFingerprint), ret.vchFingerprint);
ret.nChild = m_root_extkey.nChild;
ret.chaincode = m_root_extkey.chaincode;
ret.key = key;
return true;
}
// Derives the last xprv
bool GetDerivedExtKey(const SigningProvider& arg, CExtKey& xprv, CExtKey& last_hardened) const
{
if (!GetExtKey(arg, xprv)) return false;
for (auto entry : m_path) {
if (!xprv.Derive(xprv, entry)) return false;
if (entry >> 31) {
last_hardened = xprv;
}
}
return true;
}
bool IsHardened() const
{
if (m_derive == DeriveType::HARDENED) return true;
for (auto entry : m_path) {
if (entry >> 31) return true;
}
return false;
}
public:
BIP32PubkeyProvider(uint32_t exp_index, const CExtPubKey& extkey, KeyPath path, DeriveType derive, bool apostrophe) : PubkeyProvider(exp_index), m_root_extkey(extkey), m_path(std::move(path)), m_derive(derive), m_apostrophe(apostrophe) {}
bool IsRange() const override { return m_derive != DeriveType::NO; }
size_t GetSize() const override { return 33; }
bool GetPubKey(int pos, const SigningProvider& arg, CPubKey& key_out, KeyOriginInfo& final_info_out, const DescriptorCache* read_cache = nullptr, DescriptorCache* write_cache = nullptr) const override
{
// Info of parent of the to be derived pubkey
KeyOriginInfo parent_info;
CKeyID keyid = m_root_extkey.pubkey.GetID();
std::copy(keyid.begin(), keyid.begin() + sizeof(parent_info.fingerprint), parent_info.fingerprint);
parent_info.path = m_path;
// Info of the derived key itself which is copied out upon successful completion
KeyOriginInfo final_info_out_tmp = parent_info;
if (m_derive == DeriveType::UNHARDENED) final_info_out_tmp.path.push_back((uint32_t)pos);
if (m_derive == DeriveType::HARDENED) final_info_out_tmp.path.push_back(((uint32_t)pos) | 0x80000000L);
// Derive keys or fetch them from cache
CExtPubKey final_extkey = m_root_extkey;
CExtPubKey parent_extkey = m_root_extkey;
CExtPubKey last_hardened_extkey;
bool der = true;
if (read_cache) {
if (!read_cache->GetCachedDerivedExtPubKey(m_expr_index, pos, final_extkey)) {
if (m_derive == DeriveType::HARDENED) return false;
// Try to get the derivation parent
if (!read_cache->GetCachedParentExtPubKey(m_expr_index, parent_extkey)) return false;
final_extkey = parent_extkey;
if (m_derive == DeriveType::UNHARDENED) der = parent_extkey.Derive(final_extkey, pos);
}
} else if (IsHardened()) {
CExtKey xprv;
CExtKey lh_xprv;
if (!GetDerivedExtKey(arg, xprv, lh_xprv)) return false;
parent_extkey = xprv.Neuter();
if (m_derive == DeriveType::UNHARDENED) der = xprv.Derive(xprv, pos);
if (m_derive == DeriveType::HARDENED) der = xprv.Derive(xprv, pos | 0x80000000UL);
final_extkey = xprv.Neuter();
if (lh_xprv.key.IsValid()) {
last_hardened_extkey = lh_xprv.Neuter();
}
} else {
for (auto entry : m_path) {
if (!parent_extkey.Derive(parent_extkey, entry)) return false;
}
final_extkey = parent_extkey;
if (m_derive == DeriveType::UNHARDENED) der = parent_extkey.Derive(final_extkey, pos);
assert(m_derive != DeriveType::HARDENED);
}
if (!der) return false;
final_info_out = final_info_out_tmp;
key_out = final_extkey.pubkey;
if (write_cache) {
// Only cache parent if there is any unhardened derivation
if (m_derive != DeriveType::HARDENED) {
write_cache->CacheParentExtPubKey(m_expr_index, parent_extkey);
// Cache last hardened xpub if we have it
if (last_hardened_extkey.pubkey.IsValid()) {
write_cache->CacheLastHardenedExtPubKey(m_expr_index, last_hardened_extkey);
}
} else if (final_info_out.path.size() > 0) {
write_cache->CacheDerivedExtPubKey(m_expr_index, pos, final_extkey);
}
}
return true;
}
std::string ToString(StringType type, bool normalized) const
{
// If StringType==COMPAT, always use the apostrophe to stay compatible with previous versions
const bool use_apostrophe = (!normalized && m_apostrophe) || type == StringType::COMPAT;
std::string ret = EncodeExtPubKey(m_root_extkey) + FormatHDKeypath(m_path, /*apostrophe=*/use_apostrophe);
if (IsRange()) {
ret += "/*";
if (m_derive == DeriveType::HARDENED) ret += use_apostrophe ? '\'' : 'h';
}
return ret;
}
std::string ToString(StringType type=StringType::PUBLIC) const override
{
return ToString(type, /*normalized=*/false);
}
bool ToPrivateString(const SigningProvider& arg, std::string& out) const override
{
CExtKey key;
if (!GetExtKey(arg, key)) return false;
out = EncodeExtKey(key) + FormatHDKeypath(m_path, /*apostrophe=*/m_apostrophe);
if (IsRange()) {
out += "/*";
if (m_derive == DeriveType::HARDENED) out += m_apostrophe ? '\'' : 'h';
}
return true;
}
bool ToNormalizedString(const SigningProvider& arg, std::string& out, const DescriptorCache* cache) const override
{
if (m_derive == DeriveType::HARDENED) {
out = ToString(StringType::PUBLIC, /*normalized=*/true);
return true;
}
// Step backwards to find the last hardened step in the path
int i = (int)m_path.size() - 1;
for (; i >= 0; --i) {
if (m_path.at(i) >> 31) {
break;
}
}
// Either no derivation or all unhardened derivation
if (i == -1) {
out = ToString();
return true;
}
// Get the path to the last hardened stup
KeyOriginInfo origin;
int k = 0;
for (; k <= i; ++k) {
// Add to the path
origin.path.push_back(m_path.at(k));
}
// Build the remaining path
KeyPath end_path;
for (; k < (int)m_path.size(); ++k) {
end_path.push_back(m_path.at(k));
}
// Get the fingerprint
CKeyID id = m_root_extkey.pubkey.GetID();
std::copy(id.begin(), id.begin() + 4, origin.fingerprint);
CExtPubKey xpub;
CExtKey lh_xprv;
// If we have the cache, just get the parent xpub
if (cache != nullptr) {
cache->GetCachedLastHardenedExtPubKey(m_expr_index, xpub);
}
if (!xpub.pubkey.IsValid()) {
// Cache miss, or nor cache, or need privkey
CExtKey xprv;
if (!GetDerivedExtKey(arg, xprv, lh_xprv)) return false;
xpub = lh_xprv.Neuter();
}
assert(xpub.pubkey.IsValid());
// Build the string
std::string origin_str = HexStr(origin.fingerprint) + FormatHDKeypath(origin.path);
out = "[" + origin_str + "]" + EncodeExtPubKey(xpub) + FormatHDKeypath(end_path);
if (IsRange()) {
out += "/*";
assert(m_derive == DeriveType::UNHARDENED);
}
return true;
}
bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const override
{
CExtKey extkey;
CExtKey dummy;
if (!GetDerivedExtKey(arg, extkey, dummy)) return false;
if (m_derive == DeriveType::UNHARDENED && !extkey.Derive(extkey, pos)) return false;
if (m_derive == DeriveType::HARDENED && !extkey.Derive(extkey, pos | 0x80000000UL)) return false;
key = extkey.key;
return true;
}
std::optional<CPubKey> GetRootPubKey() const override
{
return std::nullopt;
}
std::optional<CExtPubKey> GetRootExtPubKey() const override
{
return m_root_extkey;
}
std::unique_ptr<PubkeyProvider> Clone() const override
{
return std::make_unique<BIP32PubkeyProvider>(m_expr_index, m_root_extkey, m_path, m_derive, m_apostrophe);
}
};
/** Base class for all Descriptor implementations. */
class DescriptorImpl : public Descriptor
{
protected:
//! Public key arguments for this descriptor (size 1 for PK, PKH, WPKH; any size for WSH and Multisig).
const std::vector<std::unique_ptr<PubkeyProvider>> m_pubkey_args;
//! The string name of the descriptor function.
const std::string m_name;
//! The sub-descriptor arguments (empty for everything but SH and WSH).
//! In doc/descriptors.m this is referred to as SCRIPT expressions sh(SCRIPT)
//! and wsh(SCRIPT), and distinct from KEY expressions and ADDR expressions.
//! Subdescriptors can only ever generate a single script.
const std::vector<std::unique_ptr<DescriptorImpl>> m_subdescriptor_args;
//! Return a serialization of anything except pubkey and script arguments, to be prepended to those.
virtual std::string ToStringExtra() const { return ""; }
/** A helper function to construct the scripts for this descriptor.
*
* This function is invoked once by ExpandHelper.
*
* @param pubkeys The evaluations of the m_pubkey_args field.
* @param scripts The evaluations of m_subdescriptor_args (one for each m_subdescriptor_args element).
* @param out A FlatSigningProvider to put scripts or public keys in that are necessary to the solver.
* The origin info of the provided pubkeys is automatically added.
* @return A vector with scriptPubKeys for this descriptor.
*/
virtual std::vector<CScript> MakeScripts(const std::vector<CPubKey>& pubkeys, Span<const CScript> scripts, FlatSigningProvider& out) const = 0;
public:
DescriptorImpl(std::vector<std::unique_ptr<PubkeyProvider>> pubkeys, const std::string& name) : m_pubkey_args(std::move(pubkeys)), m_name(name), m_subdescriptor_args() {}
DescriptorImpl(std::vector<std::unique_ptr<PubkeyProvider>> pubkeys, std::unique_ptr<DescriptorImpl> script, const std::string& name) : m_pubkey_args(std::move(pubkeys)), m_name(name), m_subdescriptor_args(Vector(std::move(script))) {}
DescriptorImpl(std::vector<std::unique_ptr<PubkeyProvider>> pubkeys, std::vector<std::unique_ptr<DescriptorImpl>> scripts, const std::string& name) : m_pubkey_args(std::move(pubkeys)), m_name(name), m_subdescriptor_args(std::move(scripts)) {}
enum class StringType
{
PUBLIC,
PRIVATE,
NORMALIZED,
COMPAT, // string calculation that mustn't change over time to stay compatible with previous software versions
};
// NOLINTNEXTLINE(misc-no-recursion)
bool IsSolvable() const override
{
for (const auto& arg : m_subdescriptor_args) {
if (!arg->IsSolvable()) return false;
}
return true;
}
// NOLINTNEXTLINE(misc-no-recursion)
bool IsRange() const final
{
for (const auto& pubkey : m_pubkey_args) {
if (pubkey->IsRange()) return true;
}
for (const auto& arg : m_subdescriptor_args) {
if (arg->IsRange()) return true;
}
return false;
}
// NOLINTNEXTLINE(misc-no-recursion)
virtual bool ToStringSubScriptHelper(const SigningProvider* arg, std::string& ret, const StringType type, const DescriptorCache* cache = nullptr) const
{
size_t pos = 0;
for (const auto& scriptarg : m_subdescriptor_args) {
if (pos++) ret += ",";
std::string tmp;
if (!scriptarg->ToStringHelper(arg, tmp, type, cache)) return false;
ret += tmp;
}
return true;
}
// NOLINTNEXTLINE(misc-no-recursion)
virtual bool ToStringHelper(const SigningProvider* arg, std::string& out, const StringType type, const DescriptorCache* cache = nullptr) const
{
std::string extra = ToStringExtra();
size_t pos = extra.size() > 0 ? 1 : 0;
std::string ret = m_name + "(" + extra;
for (const auto& pubkey : m_pubkey_args) {
if (pos++) ret += ",";
std::string tmp;
switch (type) {
case StringType::NORMALIZED:
if (!pubkey->ToNormalizedString(*arg, tmp, cache)) return false;
break;
case StringType::PRIVATE:
if (!pubkey->ToPrivateString(*arg, tmp)) return false;
break;
case StringType::PUBLIC:
tmp = pubkey->ToString();
break;
case StringType::COMPAT:
tmp = pubkey->ToString(PubkeyProvider::StringType::COMPAT);
break;
}
ret += tmp;
}
std::string subscript;
if (!ToStringSubScriptHelper(arg, subscript, type, cache)) return false;
if (pos && subscript.size()) ret += ',';
out = std::move(ret) + std::move(subscript) + ")";
return true;
}
std::string ToString(bool compat_format) const final
{
std::string ret;
ToStringHelper(nullptr, ret, compat_format ? StringType::COMPAT : StringType::PUBLIC);
return AddChecksum(ret);
}
bool ToPrivateString(const SigningProvider& arg, std::string& out) const override
{
bool ret = ToStringHelper(&arg, out, StringType::PRIVATE);
out = AddChecksum(out);
return ret;
}
bool ToNormalizedString(const SigningProvider& arg, std::string& out, const DescriptorCache* cache) const override final
{
bool ret = ToStringHelper(&arg, out, StringType::NORMALIZED, cache);
out = AddChecksum(out);
return ret;
}
// NOLINTNEXTLINE(misc-no-recursion)
bool ExpandHelper(int pos, const SigningProvider& arg, const DescriptorCache* read_cache, std::vector<CScript>& output_scripts, FlatSigningProvider& out, DescriptorCache* write_cache) const
{
std::vector<std::pair<CPubKey, KeyOriginInfo>> entries;
entries.reserve(m_pubkey_args.size());
// Construct temporary data in `entries`, `subscripts`, and `subprovider` to avoid producing output in case of failure.
for (const auto& p : m_pubkey_args) {
entries.emplace_back();
if (!p->GetPubKey(pos, arg, entries.back().first, entries.back().second, read_cache, write_cache)) return false;
}
std::vector<CScript> subscripts;
FlatSigningProvider subprovider;
for (const auto& subarg : m_subdescriptor_args) {
std::vector<CScript> outscripts;
if (!subarg->ExpandHelper(pos, arg, read_cache, outscripts, subprovider, write_cache)) return false;
assert(outscripts.size() == 1);
subscripts.emplace_back(std::move(outscripts[0]));
}
out.Merge(std::move(subprovider));
std::vector<CPubKey> pubkeys;
pubkeys.reserve(entries.size());
for (auto& entry : entries) {
pubkeys.push_back(entry.first);
out.origins.emplace(entry.first.GetID(), std::make_pair<CPubKey, KeyOriginInfo>(CPubKey(entry.first), std::move(entry.second)));
}
output_scripts = MakeScripts(pubkeys, Span{subscripts}, out);
return true;
}
bool Expand(int pos, const SigningProvider& provider, std::vector<CScript>& output_scripts, FlatSigningProvider& out, DescriptorCache* write_cache = nullptr) const final
{
return ExpandHelper(pos, provider, nullptr, output_scripts, out, write_cache);
}
bool ExpandFromCache(int pos, const DescriptorCache& read_cache, std::vector<CScript>& output_scripts, FlatSigningProvider& out) const final
{
return ExpandHelper(pos, DUMMY_SIGNING_PROVIDER, &read_cache, output_scripts, out, nullptr);
}
// NOLINTNEXTLINE(misc-no-recursion)
void ExpandPrivate(int pos, const SigningProvider& provider, FlatSigningProvider& out) const final
{
for (const auto& p : m_pubkey_args) {
CKey key;
if (!p->GetPrivKey(pos, provider, key)) continue;
out.keys.emplace(key.GetPubKey().GetID(), key);
}
for (const auto& arg : m_subdescriptor_args) {
arg->ExpandPrivate(pos, provider, out);
}
}
std::optional<OutputType> GetOutputType() const override { return std::nullopt; }
std::optional<int64_t> ScriptSize() const override { return {}; }
/** A helper for MaxSatisfactionWeight.
*
* @param use_max_sig Whether to assume ECDSA signatures will have a high-r.
* @return The maximum size of the satisfaction in raw bytes (with no witness meaning).
*/
virtual std::optional<int64_t> MaxSatSize(bool use_max_sig) const { return {}; }
std::optional<int64_t> MaxSatisfactionWeight(bool) const override { return {}; }
std::optional<int64_t> MaxSatisfactionElems() const override { return {}; }
// NOLINTNEXTLINE(misc-no-recursion)
void GetPubKeys(std::set<CPubKey>& pubkeys, std::set<CExtPubKey>& ext_pubs) const override
{
for (const auto& p : m_pubkey_args) {
std::optional<CPubKey> pub = p->GetRootPubKey();
if (pub) pubkeys.insert(*pub);
std::optional<CExtPubKey> ext_pub = p->GetRootExtPubKey();
if (ext_pub) ext_pubs.insert(*ext_pub);
}
for (const auto& arg : m_subdescriptor_args) {
arg->GetPubKeys(pubkeys, ext_pubs);
}
}
virtual std::unique_ptr<DescriptorImpl> Clone() const = 0;
};
/** A parsed addr(A) descriptor. */
class AddressDescriptor final : public DescriptorImpl
{
const CTxDestination m_destination;
protected:
std::string ToStringExtra() const override { return EncodeDestination(m_destination); }
std::vector<CScript> MakeScripts(const std::vector<CPubKey>&, Span<const CScript>, FlatSigningProvider&) const override { return Vector(GetScriptForDestination(m_destination)); }
public:
AddressDescriptor(CTxDestination destination) : DescriptorImpl({}, "addr"), m_destination(std::move(destination)) {}
bool IsSolvable() const final { return false; }
std::optional<OutputType> GetOutputType() const override
{
return OutputTypeFromDestination(m_destination);
}
bool IsSingleType() const final { return true; }
bool ToPrivateString(const SigningProvider& arg, std::string& out) const final { return false; }
std::optional<int64_t> ScriptSize() const override { return GetScriptForDestination(m_destination).size(); }
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<AddressDescriptor>(m_destination);
}
};
/** A parsed raw(H) descriptor. */
class RawDescriptor final : public DescriptorImpl
{
const CScript m_script;
protected:
std::string ToStringExtra() const override { return HexStr(m_script); }
std::vector<CScript> MakeScripts(const std::vector<CPubKey>&, Span<const CScript>, FlatSigningProvider&) const override { return Vector(m_script); }
public:
RawDescriptor(CScript script) : DescriptorImpl({}, "raw"), m_script(std::move(script)) {}
bool IsSolvable() const final { return false; }
std::optional<OutputType> GetOutputType() const override
{
CTxDestination dest;
ExtractDestination(m_script, dest);
return OutputTypeFromDestination(dest);
}
bool IsSingleType() const final { return true; }
bool ToPrivateString(const SigningProvider& arg, std::string& out) const final { return false; }
std::optional<int64_t> ScriptSize() const override { return m_script.size(); }
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<RawDescriptor>(m_script);
}
};
/** A parsed pk(P) descriptor. */
class PKDescriptor final : public DescriptorImpl
{
private:
const bool m_xonly;
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider&) const override
{
if (m_xonly) {
CScript script = CScript() << ToByteVector(XOnlyPubKey(keys[0])) << OP_CHECKSIG;
return Vector(std::move(script));
} else {
return Vector(GetScriptForRawPubKey(keys[0]));
}
}
public:
PKDescriptor(std::unique_ptr<PubkeyProvider> prov, bool xonly = false) : DescriptorImpl(Vector(std::move(prov)), "pk"), m_xonly(xonly) {}
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override {
return 1 + (m_xonly ? 32 : m_pubkey_args[0]->GetSize()) + 1;
}
std::optional<int64_t> MaxSatSize(bool use_max_sig) const override {
const auto ecdsa_sig_size = use_max_sig ? 72 : 71;
return 1 + (m_xonly ? 65 : ecdsa_sig_size);
}
std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const override {
return *MaxSatSize(use_max_sig) * WITNESS_SCALE_FACTOR;
}
std::optional<int64_t> MaxSatisfactionElems() const override { return 1; }
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<PKDescriptor>(m_pubkey_args.at(0)->Clone(), m_xonly);
}
};
/** A parsed pkh(P) descriptor. */
class PKHDescriptor final : public DescriptorImpl
{
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider& out) const override
{
CKeyID id = keys[0].GetID();
out.pubkeys.emplace(id, keys[0]);
return Vector(GetScriptForDestination(PKHash(id)));
}
public:
PKHDescriptor(std::unique_ptr<PubkeyProvider> prov) : DescriptorImpl(Vector(std::move(prov)), "pkh") {}
std::optional<OutputType> GetOutputType() const override { return OutputType::LEGACY; }
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override { return 1 + 1 + 1 + 20 + 1 + 1; }
std::optional<int64_t> MaxSatSize(bool use_max_sig) const override {
const auto sig_size = use_max_sig ? 72 : 71;
return 1 + sig_size + 1 + m_pubkey_args[0]->GetSize();
}
std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const override {
return *MaxSatSize(use_max_sig) * WITNESS_SCALE_FACTOR;
}
std::optional<int64_t> MaxSatisfactionElems() const override { return 2; }
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<PKHDescriptor>(m_pubkey_args.at(0)->Clone());
}
};
/** A parsed wpkh(P) descriptor. */
class WPKHDescriptor final : public DescriptorImpl
{
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider& out) const override
{
CKeyID id = keys[0].GetID();
out.pubkeys.emplace(id, keys[0]);
return Vector(GetScriptForDestination(WitnessV0KeyHash(id)));
}
public:
WPKHDescriptor(std::unique_ptr<PubkeyProvider> prov) : DescriptorImpl(Vector(std::move(prov)), "wpkh") {}
std::optional<OutputType> GetOutputType() const override { return OutputType::BECH32; }
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override { return 1 + 1 + 20; }
std::optional<int64_t> MaxSatSize(bool use_max_sig) const override {
const auto sig_size = use_max_sig ? 72 : 71;
return (1 + sig_size + 1 + 33);
}
std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const override {
return MaxSatSize(use_max_sig);
}
std::optional<int64_t> MaxSatisfactionElems() const override { return 2; }
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<WPKHDescriptor>(m_pubkey_args.at(0)->Clone());
}
};
/** A parsed combo(P) descriptor. */
class ComboDescriptor final : public DescriptorImpl
{
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider& out) const override
{
std::vector<CScript> ret;
CKeyID id = keys[0].GetID();
out.pubkeys.emplace(id, keys[0]);
ret.emplace_back(GetScriptForRawPubKey(keys[0])); // P2PK
ret.emplace_back(GetScriptForDestination(PKHash(id))); // P2PKH
if (keys[0].IsCompressed()) {
CScript p2wpkh = GetScriptForDestination(WitnessV0KeyHash(id));
out.scripts.emplace(CScriptID(p2wpkh), p2wpkh);
ret.emplace_back(p2wpkh);
ret.emplace_back(GetScriptForDestination(ScriptHash(p2wpkh))); // P2SH-P2WPKH
}
return ret;
}
public:
ComboDescriptor(std::unique_ptr<PubkeyProvider> prov) : DescriptorImpl(Vector(std::move(prov)), "combo") {}
bool IsSingleType() const final { return false; }
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<ComboDescriptor>(m_pubkey_args.at(0)->Clone());
}
};
/** A parsed multi(...) or sortedmulti(...) descriptor */
class MultisigDescriptor final : public DescriptorImpl
{
const int m_threshold;
const bool m_sorted;
protected:
std::string ToStringExtra() const override { return strprintf("%i", m_threshold); }
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider&) const override {
if (m_sorted) {
std::vector<CPubKey> sorted_keys(keys);
std::sort(sorted_keys.begin(), sorted_keys.end());
return Vector(GetScriptForMultisig(m_threshold, sorted_keys));
}
return Vector(GetScriptForMultisig(m_threshold, keys));
}
public:
MultisigDescriptor(int threshold, std::vector<std::unique_ptr<PubkeyProvider>> providers, bool sorted = false) : DescriptorImpl(std::move(providers), sorted ? "sortedmulti" : "multi"), m_threshold(threshold), m_sorted(sorted) {}
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override {
const auto n_keys = m_pubkey_args.size();
auto op = [](int64_t acc, const std::unique_ptr<PubkeyProvider>& pk) { return acc + 1 + pk->GetSize();};
const auto pubkeys_size{std::accumulate(m_pubkey_args.begin(), m_pubkey_args.end(), int64_t{0}, op)};
return 1 + BuildScript(n_keys).size() + BuildScript(m_threshold).size() + pubkeys_size;
}
std::optional<int64_t> MaxSatSize(bool use_max_sig) const override {
const auto sig_size = use_max_sig ? 72 : 71;
return (1 + (1 + sig_size) * m_threshold);
}
std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const override {
return *MaxSatSize(use_max_sig) * WITNESS_SCALE_FACTOR;
}
std::optional<int64_t> MaxSatisfactionElems() const override { return 1 + m_threshold; }
std::unique_ptr<DescriptorImpl> Clone() const override
{
std::vector<std::unique_ptr<PubkeyProvider>> providers;
providers.reserve(m_pubkey_args.size());
std::transform(m_pubkey_args.begin(), m_pubkey_args.end(), providers.begin(), [](const std::unique_ptr<PubkeyProvider>& p) { return p->Clone(); });
return std::make_unique<MultisigDescriptor>(m_threshold, std::move(providers), m_sorted);
}
};
/** A parsed (sorted)multi_a(...) descriptor. Always uses x-only pubkeys. */
class MultiADescriptor final : public DescriptorImpl
{
const int m_threshold;
const bool m_sorted;
protected:
std::string ToStringExtra() const override { return strprintf("%i", m_threshold); }
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider&) const override {
CScript ret;
std::vector<XOnlyPubKey> xkeys;
xkeys.reserve(keys.size());
for (const auto& key : keys) xkeys.emplace_back(key);
if (m_sorted) std::sort(xkeys.begin(), xkeys.end());
ret << ToByteVector(xkeys[0]) << OP_CHECKSIG;
for (size_t i = 1; i < keys.size(); ++i) {
ret << ToByteVector(xkeys[i]) << OP_CHECKSIGADD;
}
ret << m_threshold << OP_NUMEQUAL;
return Vector(std::move(ret));
}
public:
MultiADescriptor(int threshold, std::vector<std::unique_ptr<PubkeyProvider>> providers, bool sorted = false) : DescriptorImpl(std::move(providers), sorted ? "sortedmulti_a" : "multi_a"), m_threshold(threshold), m_sorted(sorted) {}
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override {
const auto n_keys = m_pubkey_args.size();
return (1 + 32 + 1) * n_keys + BuildScript(m_threshold).size() + 1;
}
std::optional<int64_t> MaxSatSize(bool use_max_sig) const override {
return (1 + 65) * m_threshold + (m_pubkey_args.size() - m_threshold);
}
std::optional<int64_t> MaxSatisfactionElems() const override { return m_pubkey_args.size(); }
std::unique_ptr<DescriptorImpl> Clone() const override
{
std::vector<std::unique_ptr<PubkeyProvider>> providers;
providers.reserve(m_pubkey_args.size());
for (const auto& arg : m_pubkey_args) {
providers.push_back(arg->Clone());
}
return std::make_unique<MultiADescriptor>(m_threshold, std::move(providers), m_sorted);
}
};
/** A parsed sh(...) descriptor. */
class SHDescriptor final : public DescriptorImpl
{
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>&, Span<const CScript> scripts, FlatSigningProvider& out) const override
{
auto ret = Vector(GetScriptForDestination(ScriptHash(scripts[0])));
if (ret.size()) out.scripts.emplace(CScriptID(scripts[0]), scripts[0]);
return ret;
}
bool IsSegwit() const { return m_subdescriptor_args[0]->GetOutputType() == OutputType::BECH32; }
public:
SHDescriptor(std::unique_ptr<DescriptorImpl> desc) : DescriptorImpl({}, std::move(desc), "sh") {}
std::optional<OutputType> GetOutputType() const override
{
assert(m_subdescriptor_args.size() == 1);
if (IsSegwit()) return OutputType::P2SH_SEGWIT;
return OutputType::LEGACY;
}
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override { return 1 + 1 + 20 + 1; }
std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const override {
if (const auto sat_size = m_subdescriptor_args[0]->MaxSatSize(use_max_sig)) {
if (const auto subscript_size = m_subdescriptor_args[0]->ScriptSize()) {
// The subscript is never witness data.
const auto subscript_weight = (1 + *subscript_size) * WITNESS_SCALE_FACTOR;
// The weight depends on whether the inner descriptor is satisfied using the witness stack.
if (IsSegwit()) return subscript_weight + *sat_size;
return subscript_weight + *sat_size * WITNESS_SCALE_FACTOR;
}
}
return {};
}
std::optional<int64_t> MaxSatisfactionElems() const override {
if (const auto sub_elems = m_subdescriptor_args[0]->MaxSatisfactionElems()) return 1 + *sub_elems;
return {};
}
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<SHDescriptor>(m_subdescriptor_args.at(0)->Clone());
}
};
/** A parsed wsh(...) descriptor. */
class WSHDescriptor final : public DescriptorImpl
{
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>&, Span<const CScript> scripts, FlatSigningProvider& out) const override
{
auto ret = Vector(GetScriptForDestination(WitnessV0ScriptHash(scripts[0])));
if (ret.size()) out.scripts.emplace(CScriptID(scripts[0]), scripts[0]);
return ret;
}
public:
WSHDescriptor(std::unique_ptr<DescriptorImpl> desc) : DescriptorImpl({}, std::move(desc), "wsh") {}
std::optional<OutputType> GetOutputType() const override { return OutputType::BECH32; }
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override { return 1 + 1 + 32; }
std::optional<int64_t> MaxSatSize(bool use_max_sig) const override {
if (const auto sat_size = m_subdescriptor_args[0]->MaxSatSize(use_max_sig)) {
if (const auto subscript_size = m_subdescriptor_args[0]->ScriptSize()) {
return GetSizeOfCompactSize(*subscript_size) + *subscript_size + *sat_size;
}
}
return {};
}
std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const override {
return MaxSatSize(use_max_sig);
}
std::optional<int64_t> MaxSatisfactionElems() const override {
if (const auto sub_elems = m_subdescriptor_args[0]->MaxSatisfactionElems()) return 1 + *sub_elems;
return {};
}
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<WSHDescriptor>(m_subdescriptor_args.at(0)->Clone());
}
};
/** A parsed tr(...) descriptor. */
class TRDescriptor final : public DescriptorImpl
{
std::vector<int> m_depths;
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript> scripts, FlatSigningProvider& out) const override
{
TaprootBuilder builder;
assert(m_depths.size() == scripts.size());
for (size_t pos = 0; pos < m_depths.size(); ++pos) {
builder.Add(m_depths[pos], scripts[pos], TAPROOT_LEAF_TAPSCRIPT);
}
if (!builder.IsComplete()) return {};
assert(keys.size() == 1);
XOnlyPubKey xpk(keys[0]);
if (!xpk.IsFullyValid()) return {};
builder.Finalize(xpk);
WitnessV1Taproot output = builder.GetOutput();
out.tr_trees[output] = builder;
out.pubkeys.emplace(keys[0].GetID(), keys[0]);
return Vector(GetScriptForDestination(output));
}
bool ToStringSubScriptHelper(const SigningProvider* arg, std::string& ret, const StringType type, const DescriptorCache* cache = nullptr) const override
{
if (m_depths.empty()) return true;
std::vector<bool> path;
for (size_t pos = 0; pos < m_depths.size(); ++pos) {
if (pos) ret += ',';
while ((int)path.size() <= m_depths[pos]) {
if (path.size()) ret += '{';
path.push_back(false);
}
std::string tmp;
if (!m_subdescriptor_args[pos]->ToStringHelper(arg, tmp, type, cache)) return false;
ret += tmp;
while (!path.empty() && path.back()) {
if (path.size() > 1) ret += '}';
path.pop_back();
}
if (!path.empty()) path.back() = true;
}
return true;
}
public:
TRDescriptor(std::unique_ptr<PubkeyProvider> internal_key, std::vector<std::unique_ptr<DescriptorImpl>> descs, std::vector<int> depths) :
DescriptorImpl(Vector(std::move(internal_key)), std::move(descs), "tr"), m_depths(std::move(depths))
{
assert(m_subdescriptor_args.size() == m_depths.size());
}
std::optional<OutputType> GetOutputType() const override { return OutputType::BECH32M; }
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override { return 1 + 1 + 32; }
std::optional<int64_t> MaxSatisfactionWeight(bool) const override {
// FIXME: We assume keypath spend, which can lead to very large underestimations.
return 1 + 65;
}
std::optional<int64_t> MaxSatisfactionElems() const override {
// FIXME: See above, we assume keypath spend.
return 1;
}
std::unique_ptr<DescriptorImpl> Clone() const override
{
std::vector<std::unique_ptr<DescriptorImpl>> subdescs;
subdescs.reserve(m_subdescriptor_args.size());
std::transform(m_subdescriptor_args.begin(), m_subdescriptor_args.end(), subdescs.begin(), [](const std::unique_ptr<DescriptorImpl>& d) { return d->Clone(); });
return std::make_unique<TRDescriptor>(m_pubkey_args.at(0)->Clone(), std::move(subdescs), m_depths);
}
};
/* We instantiate Miniscript here with a simple integer as key type.
* The value of these key integers are an index in the
* DescriptorImpl::m_pubkey_args vector.
*/
/**
* The context for converting a Miniscript descriptor into a Script.
*/
class ScriptMaker {
//! Keys contained in the Miniscript (the evaluation of DescriptorImpl::m_pubkey_args).
const std::vector<CPubKey>& m_keys;
//! The script context we're operating within (Tapscript or P2WSH).
const miniscript::MiniscriptContext m_script_ctx;
//! Get the ripemd160(sha256()) hash of this key.
//! Any key that is valid in a descriptor serializes as 32 bytes within a Tapscript context. So we
//! must not hash the sign-bit byte in this case.
uint160 GetHash160(uint32_t key) const {
if (miniscript::IsTapscript(m_script_ctx)) {
return Hash160(XOnlyPubKey{m_keys[key]});
}
return m_keys[key].GetID();
}
public:
ScriptMaker(const std::vector<CPubKey>& keys LIFETIMEBOUND, const miniscript::MiniscriptContext script_ctx) : m_keys(keys), m_script_ctx{script_ctx} {}
std::vector<unsigned char> ToPKBytes(uint32_t key) const {
// In Tapscript keys always serialize as x-only, whether an x-only key was used in the descriptor or not.
if (!miniscript::IsTapscript(m_script_ctx)) {
return {m_keys[key].begin(), m_keys[key].end()};
}
const XOnlyPubKey xonly_pubkey{m_keys[key]};
return {xonly_pubkey.begin(), xonly_pubkey.end()};
}
std::vector<unsigned char> ToPKHBytes(uint32_t key) const {
auto id = GetHash160(key);
return {id.begin(), id.end()};
}
};
/**
* The context for converting a Miniscript descriptor to its textual form.
*/
class StringMaker {
//! To convert private keys for private descriptors.
const SigningProvider* m_arg;
//! Keys contained in the Miniscript (a reference to DescriptorImpl::m_pubkey_args).
const std::vector<std::unique_ptr<PubkeyProvider>>& m_pubkeys;
//! Whether to serialize keys as private or public.
bool m_private;
public:
StringMaker(const SigningProvider* arg LIFETIMEBOUND, const std::vector<std::unique_ptr<PubkeyProvider>>& pubkeys LIFETIMEBOUND, bool priv)
: m_arg(arg), m_pubkeys(pubkeys), m_private(priv) {}
std::optional<std::string> ToString(uint32_t key) const
{
std::string ret;
if (m_private) {
if (!m_pubkeys[key]->ToPrivateString(*m_arg, ret)) return {};
} else {
ret = m_pubkeys[key]->ToString();
}
return ret;
}
};
class MiniscriptDescriptor final : public DescriptorImpl
{
private:
miniscript::NodeRef<uint32_t> m_node;
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript> scripts,
FlatSigningProvider& provider) const override
{
const auto script_ctx{m_node->GetMsCtx()};
for (const auto& key : keys) {
if (miniscript::IsTapscript(script_ctx)) {
provider.pubkeys.emplace(Hash160(XOnlyPubKey{key}), key);
} else {
provider.pubkeys.emplace(key.GetID(), key);
}
}
return Vector(m_node->ToScript(ScriptMaker(keys, script_ctx)));
}
public:
MiniscriptDescriptor(std::vector<std::unique_ptr<PubkeyProvider>> providers, miniscript::NodeRef<uint32_t> node)
: DescriptorImpl(std::move(providers), "?"), m_node(std::move(node)) {}
bool ToStringHelper(const SigningProvider* arg, std::string& out, const StringType type,
const DescriptorCache* cache = nullptr) const override
{
if (const auto res = m_node->ToString(StringMaker(arg, m_pubkey_args, type == StringType::PRIVATE))) {
out = *res;
return true;
}
return false;
}
bool IsSolvable() const override { return true; }
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override { return m_node->ScriptSize(); }
std::optional<int64_t> MaxSatSize(bool) const override {
// For Miniscript we always assume high-R ECDSA signatures.
return m_node->GetWitnessSize();
}
std::optional<int64_t> MaxSatisfactionElems() const override {
return m_node->GetStackSize();
}
std::unique_ptr<DescriptorImpl> Clone() const override
{
std::vector<std::unique_ptr<PubkeyProvider>> providers;
providers.reserve(m_pubkey_args.size());
for (const auto& arg : m_pubkey_args) {
providers.push_back(arg->Clone());
}
return std::make_unique<MiniscriptDescriptor>(std::move(providers), miniscript::MakeNodeRef<uint32_t>(*m_node));
}
};
/** A parsed rawtr(...) descriptor. */
class RawTRDescriptor final : public DescriptorImpl
{
protected:
std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript> scripts, FlatSigningProvider& out) const override
{
assert(keys.size() == 1);
XOnlyPubKey xpk(keys[0]);
if (!xpk.IsFullyValid()) return {};
WitnessV1Taproot output{xpk};
return Vector(GetScriptForDestination(output));
}
public:
RawTRDescriptor(std::unique_ptr<PubkeyProvider> output_key) : DescriptorImpl(Vector(std::move(output_key)), "rawtr") {}
std::optional<OutputType> GetOutputType() const override { return OutputType::BECH32M; }
bool IsSingleType() const final { return true; }
std::optional<int64_t> ScriptSize() const override { return 1 + 1 + 32; }
std::optional<int64_t> MaxSatisfactionWeight(bool) const override {
// We can't know whether there is a script path, so assume key path spend.
return 1 + 65;
}
std::optional<int64_t> MaxSatisfactionElems() const override {
// See above, we assume keypath spend.
return 1;
}
std::unique_ptr<DescriptorImpl> Clone() const override
{
return std::make_unique<RawTRDescriptor>(m_pubkey_args.at(0)->Clone());
}
};
////////////////////////////////////////////////////////////////////////////
// Parser //
////////////////////////////////////////////////////////////////////////////
enum class ParseScriptContext {
TOP, //!< Top-level context (script goes directly in scriptPubKey)
P2SH, //!< Inside sh() (script becomes P2SH redeemScript)
P2WPKH, //!< Inside wpkh() (no script, pubkey only)
P2WSH, //!< Inside wsh() (script becomes v0 witness script)
P2TR, //!< Inside tr() (either internal key, or BIP342 script leaf)
};
std::optional<uint32_t> ParseKeyPathNum(Span<const char> elem, bool& apostrophe, std::string& error)
{
bool hardened = false;
if (elem.size() > 0) {
const char last = elem[elem.size() - 1];
if (last == '\'' || last == 'h') {
elem = elem.first(elem.size() - 1);
hardened = true;
apostrophe = last == '\'';
}
}
uint32_t p;
if (!ParseUInt32(std::string(elem.begin(), elem.end()), &p)) {
error = strprintf("Key path value '%s' is not a valid uint32", std::string(elem.begin(), elem.end()));
return std::nullopt;
} else if (p > 0x7FFFFFFFUL) {
error = strprintf("Key path value %u is out of range", p);
return std::nullopt;
}
return std::make_optional<uint32_t>(p | (((uint32_t)hardened) << 31));
}
/**
* Parse a key path, being passed a split list of elements (the first element is ignored because it is always the key).
*
* @param[in] split BIP32 path string, using either ' or h for hardened derivation
* @param[out] out Vector of parsed key paths
* @param[out] apostrophe only updated if hardened derivation is found
* @param[out] error parsing error message
* @param[in] allow_multipath Allows the parsed path to use the multipath specifier
* @returns false if parsing failed
**/
[[nodiscard]] bool ParseKeyPath(const std::vector<Span<const char>>& split, std::vector<KeyPath>& out, bool& apostrophe, std::string& error, bool allow_multipath)
{
KeyPath path;
std::optional<size_t> multipath_segment_index;
std::vector<uint32_t> multipath_values;
std::unordered_set<uint32_t> seen_multipath;
for (size_t i = 1; i < split.size(); ++i) {
const Span<const char>& elem = split[i];
// Check if element contain multipath specifier
if (!elem.empty() && elem.front() == '<' && elem.back() == '>') {
if (!allow_multipath) {
error = strprintf("Key path value '%s' specifies multipath in a section where multipath is not allowed", std::string(elem.begin(), elem.end()));
return false;
}
if (multipath_segment_index) {
error = "Multiple multipath key path specifiers found";
return false;
}
// Parse each possible value
std::vector<Span<const char>> nums = Split(Span(elem.begin()+1, elem.end()-1), ";");
if (nums.size() < 2) {
error = "Multipath key path specifiers must have at least two items";
return false;
}
for (const auto& num : nums) {
const auto& op_num = ParseKeyPathNum(num, apostrophe, error);
if (!op_num) return false;
auto [_, inserted] = seen_multipath.insert(*op_num);
if (!inserted) {
error = strprintf("Duplicated key path value %u in multipath specifier", *op_num);
return false;
}
multipath_values.emplace_back(*op_num);
}
path.emplace_back(); // Placeholder for multipath segment
multipath_segment_index = path.size()-1;
} else {
const auto& op_num = ParseKeyPathNum(elem, apostrophe, error);
if (!op_num) return false;
path.emplace_back(*op_num);
}
}
if (!multipath_segment_index) {
out.emplace_back(std::move(path));
} else {
// Replace the multipath placeholder with each value while generating paths
for (size_t i = 0; i < multipath_values.size(); i++) {
KeyPath branch_path = path;
branch_path[*multipath_segment_index] = multipath_values[i];
out.emplace_back(std::move(branch_path));
}
}
return true;
}
/** Parse a public key that excludes origin information. */
std::vector<std::unique_ptr<PubkeyProvider>> ParsePubkeyInner(uint32_t key_exp_index, const Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, bool& apostrophe, std::string& error)
{
std::vector<std::unique_ptr<PubkeyProvider>> ret;
bool permit_uncompressed = ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH;
auto split = Split(sp, '/');
std::string str(split[0].begin(), split[0].end());
if (str.size() == 0) {
error = "No key provided";
return {};
}
if (split.size() == 1) {
if (IsHex(str)) {
std::vector<unsigned char> data = ParseHex(str);
CPubKey pubkey(data);
if (pubkey.IsValid() && !pubkey.IsValidNonHybrid()) {
error = "Hybrid public keys are not allowed";
return {};
}
if (pubkey.IsFullyValid()) {
if (permit_uncompressed || pubkey.IsCompressed()) {
ret.emplace_back(std::make_unique<ConstPubkeyProvider>(key_exp_index, pubkey, false));
return ret;
} else {
error = "Uncompressed keys are not allowed";
return {};
}
} else if (data.size() == 32 && ctx == ParseScriptContext::P2TR) {
unsigned char fullkey[33] = {0x02};
std::copy(data.begin(), data.end(), fullkey + 1);
pubkey.Set(std::begin(fullkey), std::end(fullkey));
if (pubkey.IsFullyValid()) {
ret.emplace_back(std::make_unique<ConstPubkeyProvider>(key_exp_index, pubkey, true));
return ret;
}
}
error = strprintf("Pubkey '%s' is invalid", str);
return {};
}
CKey key = DecodeSecret(str);
if (key.IsValid()) {
if (permit_uncompressed || key.IsCompressed()) {
CPubKey pubkey = key.GetPubKey();
out.keys.emplace(pubkey.GetID(), key);
ret.emplace_back(std::make_unique<ConstPubkeyProvider>(key_exp_index, pubkey, ctx == ParseScriptContext::P2TR));
return ret;
} else {
error = "Uncompressed keys are not allowed";
return {};
}
}
}
CExtKey extkey = DecodeExtKey(str);
CExtPubKey extpubkey = DecodeExtPubKey(str);
if (!extkey.key.IsValid() && !extpubkey.pubkey.IsValid()) {
error = strprintf("key '%s' is not valid", str);
return {};
}
std::vector<KeyPath> paths;
DeriveType type = DeriveType::NO;
if (std::ranges::equal(split.back(), Span{"*"}.first(1))) {
split.pop_back();
type = DeriveType::UNHARDENED;
} else if (std::ranges::equal(split.back(), Span{"*'"}.first(2)) || std::ranges::equal(split.back(), Span{"*h"}.first(2))) {
apostrophe = std::ranges::equal(split.back(), Span{"*'"}.first(2));
split.pop_back();
type = DeriveType::HARDENED;
}
if (!ParseKeyPath(split, paths, apostrophe, error, /*allow_multipath=*/true)) return {};
if (extkey.key.IsValid()) {
extpubkey = extkey.Neuter();
out.keys.emplace(extpubkey.pubkey.GetID(), extkey.key);
}
for (auto& path : paths) {
ret.emplace_back(std::make_unique<BIP32PubkeyProvider>(key_exp_index, extpubkey, std::move(path), type, apostrophe));
}
return ret;
}
/** Parse a public key including origin information (if enabled). */
std::vector<std::unique_ptr<PubkeyProvider>> ParsePubkey(uint32_t key_exp_index, const Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, std::string& error)
{
std::vector<std::unique_ptr<PubkeyProvider>> ret;
auto origin_split = Split(sp, ']');
if (origin_split.size() > 2) {
error = "Multiple ']' characters found for a single pubkey";
return {};
}
// This is set if either the origin or path suffix contains a hardened derivation.
bool apostrophe = false;
if (origin_split.size() == 1) {
return ParsePubkeyInner(key_exp_index, origin_split[0], ctx, out, apostrophe, error);
}
if (origin_split[0].empty() || origin_split[0][0] != '[') {
error = strprintf("Key origin start '[ character expected but not found, got '%c' instead",
origin_split[0].empty() ? /** empty, implies split char */ ']' : origin_split[0][0]);
return {};
}
auto slash_split = Split(origin_split[0].subspan(1), '/');
if (slash_split[0].size() != 8) {
error = strprintf("Fingerprint is not 4 bytes (%u characters instead of 8 characters)", slash_split[0].size());
return {};
}
std::string fpr_hex = std::string(slash_split[0].begin(), slash_split[0].end());
if (!IsHex(fpr_hex)) {
error = strprintf("Fingerprint '%s' is not hex", fpr_hex);
return {};
}
auto fpr_bytes = ParseHex(fpr_hex);
KeyOriginInfo info;
static_assert(sizeof(info.fingerprint) == 4, "Fingerprint must be 4 bytes");
assert(fpr_bytes.size() == 4);
std::copy(fpr_bytes.begin(), fpr_bytes.end(), info.fingerprint);
std::vector<KeyPath> path;
if (!ParseKeyPath(slash_split, path, apostrophe, error, /*allow_multipath=*/false)) return {};
info.path = path.at(0);
auto providers = ParsePubkeyInner(key_exp_index, origin_split[1], ctx, out, apostrophe, error);
if (providers.empty()) return {};
ret.reserve(providers.size());
for (auto& prov : providers) {
ret.emplace_back(std::make_unique<OriginPubkeyProvider>(key_exp_index, info, std::move(prov), apostrophe));
}
return ret;
}
std::unique_ptr<PubkeyProvider> InferPubkey(const CPubKey& pubkey, ParseScriptContext ctx, const SigningProvider& provider)
{
// Key cannot be hybrid
if (!pubkey.IsValidNonHybrid()) {
return nullptr;
}
// Uncompressed is only allowed in TOP and P2SH contexts
if (ctx != ParseScriptContext::TOP && ctx != ParseScriptContext::P2SH && !pubkey.IsCompressed()) {
return nullptr;
}
std::unique_ptr<PubkeyProvider> key_provider = std::make_unique<ConstPubkeyProvider>(0, pubkey, false);
KeyOriginInfo info;
if (provider.GetKeyOrigin(pubkey.GetID(), info)) {
return std::make_unique<OriginPubkeyProvider>(0, std::move(info), std::move(key_provider), /*apostrophe=*/false);
}
return key_provider;
}
std::unique_ptr<PubkeyProvider> InferXOnlyPubkey(const XOnlyPubKey& xkey, ParseScriptContext ctx, const SigningProvider& provider)
{
CPubKey pubkey{xkey.GetEvenCorrespondingCPubKey()};
std::unique_ptr<PubkeyProvider> key_provider = std::make_unique<ConstPubkeyProvider>(0, pubkey, true);
KeyOriginInfo info;
if (provider.GetKeyOriginByXOnly(xkey, info)) {
return std::make_unique<OriginPubkeyProvider>(0, std::move(info), std::move(key_provider), /*apostrophe=*/false);
}
return key_provider;
}
/**
* The context for parsing a Miniscript descriptor (either from Script or from its textual representation).
*/
struct KeyParser {
//! The Key type is an index in DescriptorImpl::m_pubkey_args
using Key = uint32_t;
//! Must not be nullptr if parsing from string.
FlatSigningProvider* m_out;
//! Must not be nullptr if parsing from Script.
const SigningProvider* m_in;
//! List of multipath expanded keys contained in the Miniscript.
mutable std::vector<std::vector<std::unique_ptr<PubkeyProvider>>> m_keys;
//! Used to detect key parsing errors within a Miniscript.
mutable std::string m_key_parsing_error;
//! The script context we're operating within (Tapscript or P2WSH).
const miniscript::MiniscriptContext m_script_ctx;
//! The number of keys that were parsed before starting to parse this Miniscript descriptor.
uint32_t m_offset;
KeyParser(FlatSigningProvider* out LIFETIMEBOUND, const SigningProvider* in LIFETIMEBOUND,
miniscript::MiniscriptContext ctx, uint32_t offset = 0)
: m_out(out), m_in(in), m_script_ctx(ctx), m_offset(offset) {}
bool KeyCompare(const Key& a, const Key& b) const {
return *m_keys.at(a).at(0) < *m_keys.at(b).at(0);
}
ParseScriptContext ParseContext() const {
switch (m_script_ctx) {
case miniscript::MiniscriptContext::P2WSH: return ParseScriptContext::P2WSH;
case miniscript::MiniscriptContext::TAPSCRIPT: return ParseScriptContext::P2TR;
}
assert(false);
}
template<typename I> std::optional<Key> FromString(I begin, I end) const
{
assert(m_out);
Key key = m_keys.size();
auto pk = ParsePubkey(m_offset + key, {&*begin, &*end}, ParseContext(), *m_out, m_key_parsing_error);
if (pk.empty()) return {};
m_keys.emplace_back(std::move(pk));
return key;
}
std::optional<std::string> ToString(const Key& key) const
{
return m_keys.at(key).at(0)->ToString();
}
template<typename I> std::optional<Key> FromPKBytes(I begin, I end) const
{
assert(m_in);
Key key = m_keys.size();
if (miniscript::IsTapscript(m_script_ctx) && end - begin == 32) {
XOnlyPubKey pubkey;
std::copy(begin, end, pubkey.begin());
if (auto pubkey_provider = InferPubkey(pubkey.GetEvenCorrespondingCPubKey(), ParseContext(), *m_in)) {
m_keys.emplace_back();
m_keys.back().push_back(std::move(pubkey_provider));
return key;
}
} else if (!miniscript::IsTapscript(m_script_ctx)) {
CPubKey pubkey(begin, end);
if (auto pubkey_provider = InferPubkey(pubkey, ParseContext(), *m_in)) {
m_keys.emplace_back();
m_keys.back().push_back(std::move(pubkey_provider));
return key;
}
}
return {};
}
template<typename I> std::optional<Key> FromPKHBytes(I begin, I end) const
{
assert(end - begin == 20);
assert(m_in);
uint160 hash;
std::copy(begin, end, hash.begin());
CKeyID keyid(hash);
CPubKey pubkey;
if (m_in->GetPubKey(keyid, pubkey)) {
if (auto pubkey_provider = InferPubkey(pubkey, ParseContext(), *m_in)) {
Key key = m_keys.size();
m_keys.emplace_back();
m_keys.back().push_back(std::move(pubkey_provider));
return key;
}
}
return {};
}
miniscript::MiniscriptContext MsContext() const {
return m_script_ctx;
}
};
/** Parse a script in a particular context. */
// NOLINTNEXTLINE(misc-no-recursion)
std::vector<std::unique_ptr<DescriptorImpl>> ParseScript(uint32_t& key_exp_index, Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, std::string& error)
{
using namespace script;
std::vector<std::unique_ptr<DescriptorImpl>> ret;
auto expr = Expr(sp);
if (Func("pk", expr)) {
auto pubkeys = ParsePubkey(key_exp_index, expr, ctx, out, error);
if (pubkeys.empty()) {
error = strprintf("pk(): %s", error);
return {};
}
++key_exp_index;
for (auto& pubkey : pubkeys) {
ret.emplace_back(std::make_unique<PKDescriptor>(std::move(pubkey), ctx == ParseScriptContext::P2TR));
}
return ret;
}
if ((ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH) && Func("pkh", expr)) {
auto pubkeys = ParsePubkey(key_exp_index, expr, ctx, out, error);
if (pubkeys.empty()) {
error = strprintf("pkh(): %s", error);
return {};
}
++key_exp_index;
for (auto& pubkey : pubkeys) {
ret.emplace_back(std::make_unique<PKHDescriptor>(std::move(pubkey)));
}
return ret;
} else if (ctx != ParseScriptContext::P2TR && Func("pkh", expr)) {
// Under Taproot, always the Miniscript parser deal with it.
error = "Can only have pkh at top level, in sh(), wsh(), or in tr()";
return {};
}
if (ctx == ParseScriptContext::TOP && Func("combo", expr)) {
auto pubkeys = ParsePubkey(key_exp_index, expr, ctx, out, error);
if (pubkeys.empty()) {
error = strprintf("combo(): %s", error);
return {};
}
++key_exp_index;
for (auto& pubkey : pubkeys) {
ret.emplace_back(std::make_unique<ComboDescriptor>(std::move(pubkey)));
}
return ret;
} else if (Func("combo", expr)) {
error = "Can only have combo() at top level";
return {};
}
const bool multi = Func("multi", expr);
const bool sortedmulti = !multi && Func("sortedmulti", expr);
const bool multi_a = !(multi || sortedmulti) && Func("multi_a", expr);
const bool sortedmulti_a = !(multi || sortedmulti || multi_a) && Func("sortedmulti_a", expr);
if (((ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH) && (multi || sortedmulti)) ||
(ctx == ParseScriptContext::P2TR && (multi_a || sortedmulti_a))) {
auto threshold = Expr(expr);
uint32_t thres;
std::vector<std::vector<std::unique_ptr<PubkeyProvider>>> providers; // List of multipath expanded pubkeys
if (!ParseUInt32(std::string(threshold.begin(), threshold.end()), &thres)) {
error = strprintf("Multi threshold '%s' is not valid", std::string(threshold.begin(), threshold.end()));
return {};
}
size_t script_size = 0;
size_t max_providers_len = 0;
while (expr.size()) {
if (!Const(",", expr)) {
error = strprintf("Multi: expected ',', got '%c'", expr[0]);
return {};
}
auto arg = Expr(expr);
auto pks = ParsePubkey(key_exp_index, arg, ctx, out, error);
if (pks.empty()) {
error = strprintf("Multi: %s", error);
return {};
}
script_size += pks.at(0)->GetSize() + 1;
max_providers_len = std::max(max_providers_len, pks.size());
providers.emplace_back(std::move(pks));
key_exp_index++;
}
if ((multi || sortedmulti) && (providers.empty() || providers.size() > MAX_PUBKEYS_PER_MULTISIG)) {
error = strprintf("Cannot have %u keys in multisig; must have between 1 and %d keys, inclusive", providers.size(), MAX_PUBKEYS_PER_MULTISIG);
return {};
} else if ((multi_a || sortedmulti_a) && (providers.empty() || providers.size() > MAX_PUBKEYS_PER_MULTI_A)) {
error = strprintf("Cannot have %u keys in multi_a; must have between 1 and %d keys, inclusive", providers.size(), MAX_PUBKEYS_PER_MULTI_A);
return {};
} else if (thres < 1) {
error = strprintf("Multisig threshold cannot be %d, must be at least 1", thres);
return {};
} else if (thres > providers.size()) {
error = strprintf("Multisig threshold cannot be larger than the number of keys; threshold is %d but only %u keys specified", thres, providers.size());
return {};
}
if (ctx == ParseScriptContext::TOP) {
if (providers.size() > 3) {
error = strprintf("Cannot have %u pubkeys in bare multisig; only at most 3 pubkeys", providers.size());
return {};
}
}
if (ctx == ParseScriptContext::P2SH) {
// This limits the maximum number of compressed pubkeys to 15.
if (script_size + 3 > MAX_SCRIPT_ELEMENT_SIZE) {
error = strprintf("P2SH script is too large, %d bytes is larger than %d bytes", script_size + 3, MAX_SCRIPT_ELEMENT_SIZE);
return {};
}
}
// Make sure all vecs are of the same length, or exactly length 1
// For length 1 vectors, clone key providers until vector is the same length
for (auto& vec : providers) {
if (vec.size() == 1) {
for (size_t i = 1; i < max_providers_len; ++i) {
vec.emplace_back(vec.at(0)->Clone());
}
} else if (vec.size() != max_providers_len) {
error = strprintf("multi(): Multipath derivation paths have mismatched lengths");
return {};
}
}
// Build the final descriptors vector
for (size_t i = 0; i < max_providers_len; ++i) {
// Build final pubkeys vectors by retrieving the i'th subscript for each vector in subscripts
std::vector<std::unique_ptr<PubkeyProvider>> pubs;
pubs.reserve(providers.size());
for (auto& pub : providers) {
pubs.emplace_back(std::move(pub.at(i)));
}
if (multi || sortedmulti) {
ret.emplace_back(std::make_unique<MultisigDescriptor>(thres, std::move(pubs), sortedmulti));
} else {
ret.emplace_back(std::make_unique<MultiADescriptor>(thres, std::move(pubs), sortedmulti_a));
}
}
return ret;
} else if (multi || sortedmulti) {
error = "Can only have multi/sortedmulti at top level, in sh(), or in wsh()";
return {};
} else if (multi_a || sortedmulti_a) {
error = "Can only have multi_a/sortedmulti_a inside tr()";
return {};
}
if ((ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH) && Func("wpkh", expr)) {
auto pubkeys = ParsePubkey(key_exp_index, expr, ParseScriptContext::P2WPKH, out, error);
if (pubkeys.empty()) {
error = strprintf("wpkh(): %s", error);
return {};
}
key_exp_index++;
for (auto& pubkey : pubkeys) {
ret.emplace_back(std::make_unique<WPKHDescriptor>(std::move(pubkey)));
}
return ret;
} else if (Func("wpkh", expr)) {
error = "Can only have wpkh() at top level or inside sh()";
return {};
}
if (ctx == ParseScriptContext::TOP && Func("sh", expr)) {
auto descs = ParseScript(key_exp_index, expr, ParseScriptContext::P2SH, out, error);
if (descs.empty() || expr.size()) return {};
std::vector<std::unique_ptr<DescriptorImpl>> ret;
ret.reserve(descs.size());
for (auto& desc : descs) {
ret.push_back(std::make_unique<SHDescriptor>(std::move(desc)));
}
return ret;
} else if (Func("sh", expr)) {
error = "Can only have sh() at top level";
return {};
}
if ((ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH) && Func("wsh", expr)) {
auto descs = ParseScript(key_exp_index, expr, ParseScriptContext::P2WSH, out, error);
if (descs.empty() || expr.size()) return {};
for (auto& desc : descs) {
ret.emplace_back(std::make_unique<WSHDescriptor>(std::move(desc)));
}
return ret;
} else if (Func("wsh", expr)) {
error = "Can only have wsh() at top level or inside sh()";
return {};
}
if (ctx == ParseScriptContext::TOP && Func("addr", expr)) {
CTxDestination dest = DecodeDestination(std::string(expr.begin(), expr.end()));
if (!IsValidDestination(dest)) {
error = "Address is not valid";
return {};
}
ret.emplace_back(std::make_unique<AddressDescriptor>(std::move(dest)));
return ret;
} else if (Func("addr", expr)) {
error = "Can only have addr() at top level";
return {};
}
if (ctx == ParseScriptContext::TOP && Func("tr", expr)) {
auto arg = Expr(expr);
auto internal_keys = ParsePubkey(key_exp_index, arg, ParseScriptContext::P2TR, out, error);
if (internal_keys.empty()) {
error = strprintf("tr(): %s", error);
return {};
}
size_t max_providers_len = internal_keys.size();
++key_exp_index;
std::vector<std::vector<std::unique_ptr<DescriptorImpl>>> subscripts; //!< list of multipath expanded script subexpressions
std::vector<int> depths; //!< depth in the tree of each subexpression (same length subscripts)
if (expr.size()) {
if (!Const(",", expr)) {
error = strprintf("tr: expected ',', got '%c'", expr[0]);
return {};
}
/** The path from the top of the tree to what we're currently processing.
* branches[i] == false: left branch in the i'th step from the top; true: right branch.
*/
std::vector<bool> branches;
// Loop over all provided scripts. In every iteration exactly one script will be processed.
// Use a do-loop because inside this if-branch we expect at least one script.
do {
// First process all open braces.
while (Const("{", expr)) {
branches.push_back(false); // new left branch
if (branches.size() > TAPROOT_CONTROL_MAX_NODE_COUNT) {
error = strprintf("tr() supports at most %i nesting levels", TAPROOT_CONTROL_MAX_NODE_COUNT);
return {};
}
}
// Process the actual script expression.
auto sarg = Expr(expr);
subscripts.emplace_back(ParseScript(key_exp_index, sarg, ParseScriptContext::P2TR, out, error));
if (subscripts.back().empty()) return {};
max_providers_len = std::max(max_providers_len, subscripts.back().size());
depths.push_back(branches.size());
// Process closing braces; one is expected for every right branch we were in.
while (branches.size() && branches.back()) {
if (!Const("}", expr)) {
error = strprintf("tr(): expected '}' after script expression");
return {};
}
branches.pop_back(); // move up one level after encountering '}'
}
// If after that, we're at the end of a left branch, expect a comma.
if (branches.size() && !branches.back()) {
if (!Const(",", expr)) {
error = strprintf("tr(): expected ',' after script expression");
return {};
}
branches.back() = true; // And now we're in a right branch.
}
} while (branches.size());
// After we've explored a whole tree, we must be at the end of the expression.
if (expr.size()) {
error = strprintf("tr(): expected ')' after script expression");
return {};
}
}
assert(TaprootBuilder::ValidDepths(depths));
// Make sure all vecs are of the same length, or exactly length 1
// For length 1 vectors, clone subdescs until vector is the same length
for (auto& vec : subscripts) {
if (vec.size() == 1) {
for (size_t i = 1; i < max_providers_len; ++i) {
vec.emplace_back(vec.at(0)->Clone());
}
} else if (vec.size() != max_providers_len) {
error = strprintf("tr(): Multipath subscripts have mismatched lengths");
return {};
}
}
if (internal_keys.size() > 1 && internal_keys.size() != max_providers_len) {
error = strprintf("tr(): Multipath internal key mismatches multipath subscripts lengths");
return {};
}
while (internal_keys.size() < max_providers_len) {
internal_keys.emplace_back(internal_keys.at(0)->Clone());
}
// Build the final descriptors vector
for (size_t i = 0; i < max_providers_len; ++i) {
// Build final subscripts vectors by retrieving the i'th subscript for each vector in subscripts
std::vector<std::unique_ptr<DescriptorImpl>> this_subs;
this_subs.reserve(subscripts.size());
for (auto& subs : subscripts) {
this_subs.emplace_back(std::move(subs.at(i)));
}
ret.emplace_back(std::make_unique<TRDescriptor>(std::move(internal_keys.at(i)), std::move(this_subs), depths));
}
return ret;
} else if (Func("tr", expr)) {
error = "Can only have tr at top level";
return {};
}
if (ctx == ParseScriptContext::TOP && Func("rawtr", expr)) {
auto arg = Expr(expr);
if (expr.size()) {
error = strprintf("rawtr(): only one key expected.");
return {};
}
auto output_keys = ParsePubkey(key_exp_index, arg, ParseScriptContext::P2TR, out, error);
if (output_keys.empty()) {
error = strprintf("rawtr(): %s", error);
return {};
}
++key_exp_index;
for (auto& pubkey : output_keys) {
ret.emplace_back(std::make_unique<RawTRDescriptor>(std::move(pubkey)));
}
return ret;
} else if (Func("rawtr", expr)) {
error = "Can only have rawtr at top level";
return {};
}
if (ctx == ParseScriptContext::TOP && Func("raw", expr)) {
std::string str(expr.begin(), expr.end());
if (!IsHex(str)) {
error = "Raw script is not hex";
return {};
}
auto bytes = ParseHex(str);
ret.emplace_back(std::make_unique<RawDescriptor>(CScript(bytes.begin(), bytes.end())));
return ret;
} else if (Func("raw", expr)) {
error = "Can only have raw() at top level";
return {};
}
// Process miniscript expressions.
{
const auto script_ctx{ctx == ParseScriptContext::P2WSH ? miniscript::MiniscriptContext::P2WSH : miniscript::MiniscriptContext::TAPSCRIPT};
KeyParser parser(/*out = */&out, /* in = */nullptr, /* ctx = */script_ctx, key_exp_index);
auto node = miniscript::FromString(std::string(expr.begin(), expr.end()), parser);
if (parser.m_key_parsing_error != "") {
error = std::move(parser.m_key_parsing_error);
return {};
}
if (node) {
if (ctx != ParseScriptContext::P2WSH && ctx != ParseScriptContext::P2TR) {
error = "Miniscript expressions can only be used in wsh or tr.";
return {};
}
if (!node->IsSane() || node->IsNotSatisfiable()) {
// Try to find the first insane sub for better error reporting.
auto insane_node = node.get();
if (const auto sub = node->FindInsaneSub()) insane_node = sub;
if (const auto str = insane_node->ToString(parser)) error = *str;
if (!insane_node->IsValid()) {
error += " is invalid";
} else if (!node->IsSane()) {
error += " is not sane";
if (!insane_node->IsNonMalleable()) {
error += ": malleable witnesses exist";
} else if (insane_node == node.get() && !insane_node->NeedsSignature()) {
error += ": witnesses without signature exist";
} else if (!insane_node->CheckTimeLocksMix()) {
error += ": contains mixes of timelocks expressed in blocks and seconds";
} else if (!insane_node->CheckDuplicateKey()) {
error += ": contains duplicate public keys";
} else if (!insane_node->ValidSatisfactions()) {
error += ": needs witnesses that may exceed resource limits";
}
} else {
error += " is not satisfiable";
}
return {};
}
// A signature check is required for a miniscript to be sane. Therefore no sane miniscript
// may have an empty list of public keys.
CHECK_NONFATAL(!parser.m_keys.empty());
key_exp_index += parser.m_keys.size();
// Make sure all vecs are of the same length, or exactly length 1
// For length 1 vectors, clone subdescs until vector is the same length
size_t num_multipath = std::max_element(parser.m_keys.begin(), parser.m_keys.end(),
[](const std::vector<std::unique_ptr<PubkeyProvider>>& a, const std::vector<std::unique_ptr<PubkeyProvider>>& b) {
return a.size() < b.size();
})->size();
for (auto& vec : parser.m_keys) {
if (vec.size() == 1) {
for (size_t i = 1; i < num_multipath; ++i) {
vec.emplace_back(vec.at(0)->Clone());
}
} else if (vec.size() != num_multipath) {
error = strprintf("Miniscript: Multipath derivation paths have mismatched lengths");
return {};
}
}
// Build the final descriptors vector
for (size_t i = 0; i < num_multipath; ++i) {
// Build final pubkeys vectors by retrieving the i'th subscript for each vector in subscripts
std::vector<std::unique_ptr<PubkeyProvider>> pubs;
pubs.reserve(parser.m_keys.size());
for (auto& pub : parser.m_keys) {
pubs.emplace_back(std::move(pub.at(i)));
}
ret.emplace_back(std::make_unique<MiniscriptDescriptor>(std::move(pubs), node));
}
return ret;
}
}
if (ctx == ParseScriptContext::P2SH) {
error = "A function is needed within P2SH";
return {};
} else if (ctx == ParseScriptContext::P2WSH) {
error = "A function is needed within P2WSH";
return {};
}
error = strprintf("'%s' is not a valid descriptor function", std::string(expr.begin(), expr.end()));
return {};
}
std::unique_ptr<DescriptorImpl> InferMultiA(const CScript& script, ParseScriptContext ctx, const SigningProvider& provider)
{
auto match = MatchMultiA(script);
if (!match) return {};
std::vector<std::unique_ptr<PubkeyProvider>> keys;
keys.reserve(match->second.size());
for (const auto keyspan : match->second) {
if (keyspan.size() != 32) return {};
auto key = InferXOnlyPubkey(XOnlyPubKey{keyspan}, ctx, provider);
if (!key) return {};
keys.push_back(std::move(key));
}
return std::make_unique<MultiADescriptor>(match->first, std::move(keys));
}
// NOLINTNEXTLINE(misc-no-recursion)
std::unique_ptr<DescriptorImpl> InferScript(const CScript& script, ParseScriptContext ctx, const SigningProvider& provider)
{
if (ctx == ParseScriptContext::P2TR && script.size() == 34 && script[0] == 32 && script[33] == OP_CHECKSIG) {
XOnlyPubKey key{Span{script}.subspan(1, 32)};
return std::make_unique<PKDescriptor>(InferXOnlyPubkey(key, ctx, provider), true);
}
if (ctx == ParseScriptContext::P2TR) {
auto ret = InferMultiA(script, ctx, provider);
if (ret) return ret;
}
std::vector<std::vector<unsigned char>> data;
TxoutType txntype = Solver(script, data);
if (txntype == TxoutType::PUBKEY && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH)) {
CPubKey pubkey(data[0]);
if (auto pubkey_provider = InferPubkey(pubkey, ctx, provider)) {
return std::make_unique<PKDescriptor>(std::move(pubkey_provider));
}
}
if (txntype == TxoutType::PUBKEYHASH && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH)) {
uint160 hash(data[0]);
CKeyID keyid(hash);
CPubKey pubkey;
if (provider.GetPubKey(keyid, pubkey)) {
if (auto pubkey_provider = InferPubkey(pubkey, ctx, provider)) {
return std::make_unique<PKHDescriptor>(std::move(pubkey_provider));
}
}
}
if (txntype == TxoutType::WITNESS_V0_KEYHASH && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH)) {
uint160 hash(data[0]);
CKeyID keyid(hash);
CPubKey pubkey;
if (provider.GetPubKey(keyid, pubkey)) {
if (auto pubkey_provider = InferPubkey(pubkey, ParseScriptContext::P2WPKH, provider)) {
return std::make_unique<WPKHDescriptor>(std::move(pubkey_provider));
}
}
}
if (txntype == TxoutType::MULTISIG && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH)) {
bool ok = true;
std::vector<std::unique_ptr<PubkeyProvider>> providers;
for (size_t i = 1; i + 1 < data.size(); ++i) {
CPubKey pubkey(data[i]);
if (auto pubkey_provider = InferPubkey(pubkey, ctx, provider)) {
providers.push_back(std::move(pubkey_provider));
} else {
ok = false;
break;
}
}
if (ok) return std::make_unique<MultisigDescriptor>((int)data[0][0], std::move(providers));
}
if (txntype == TxoutType::SCRIPTHASH && ctx == ParseScriptContext::TOP) {
uint160 hash(data[0]);
CScriptID scriptid(hash);
CScript subscript;
if (provider.GetCScript(scriptid, subscript)) {
auto sub = InferScript(subscript, ParseScriptContext::P2SH, provider);
if (sub) return std::make_unique<SHDescriptor>(std::move(sub));
}
}
if (txntype == TxoutType::WITNESS_V0_SCRIPTHASH && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH)) {
CScriptID scriptid{RIPEMD160(data[0])};
CScript subscript;
if (provider.GetCScript(scriptid, subscript)) {
auto sub = InferScript(subscript, ParseScriptContext::P2WSH, provider);
if (sub) return std::make_unique<WSHDescriptor>(std::move(sub));
}
}
if (txntype == TxoutType::WITNESS_V1_TAPROOT && ctx == ParseScriptContext::TOP) {
// Extract x-only pubkey from output.
XOnlyPubKey pubkey;
std::copy(data[0].begin(), data[0].end(), pubkey.begin());
// Request spending data.
TaprootSpendData tap;
if (provider.GetTaprootSpendData(pubkey, tap)) {
// If found, convert it back to tree form.
auto tree = InferTaprootTree(tap, pubkey);
if (tree) {
// If that works, try to infer subdescriptors for all leaves.
bool ok = true;
std::vector<std::unique_ptr<DescriptorImpl>> subscripts; //!< list of script subexpressions
std::vector<int> depths; //!< depth in the tree of each subexpression (same length subscripts)
for (const auto& [depth, script, leaf_ver] : *tree) {
std::unique_ptr<DescriptorImpl> subdesc;
if (leaf_ver == TAPROOT_LEAF_TAPSCRIPT) {
subdesc = InferScript(CScript(script.begin(), script.end()), ParseScriptContext::P2TR, provider);
}
if (!subdesc) {
ok = false;
break;
} else {
subscripts.push_back(std::move(subdesc));
depths.push_back(depth);
}
}
if (ok) {
auto key = InferXOnlyPubkey(tap.internal_key, ParseScriptContext::P2TR, provider);
return std::make_unique<TRDescriptor>(std::move(key), std::move(subscripts), std::move(depths));
}
}
}
// If the above doesn't work, construct a rawtr() descriptor with just the encoded x-only pubkey.
if (pubkey.IsFullyValid()) {
auto key = InferXOnlyPubkey(pubkey, ParseScriptContext::P2TR, provider);
if (key) {
return std::make_unique<RawTRDescriptor>(std::move(key));
}
}
}
if (ctx == ParseScriptContext::P2WSH || ctx == ParseScriptContext::P2TR) {
const auto script_ctx{ctx == ParseScriptContext::P2WSH ? miniscript::MiniscriptContext::P2WSH : miniscript::MiniscriptContext::TAPSCRIPT};
KeyParser parser(/* out = */nullptr, /* in = */&provider, /* ctx = */script_ctx);
auto node = miniscript::FromScript(script, parser);
if (node && node->IsSane()) {
std::vector<std::unique_ptr<PubkeyProvider>> keys;
keys.reserve(parser.m_keys.size());
for (auto& key : parser.m_keys) {
keys.emplace_back(std::move(key.at(0)));
}
return std::make_unique<MiniscriptDescriptor>(std::move(keys), std::move(node));
}
}
// The following descriptors are all top-level only descriptors.
// So if we are not at the top level, return early.
if (ctx != ParseScriptContext::TOP) return nullptr;
CTxDestination dest;
if (ExtractDestination(script, dest)) {
if (GetScriptForDestination(dest) == script) {
return std::make_unique<AddressDescriptor>(std::move(dest));
}
}
return std::make_unique<RawDescriptor>(script);
}
} // namespace
/** Check a descriptor checksum, and update desc to be the checksum-less part. */
bool CheckChecksum(Span<const char>& sp, bool require_checksum, std::string& error, std::string* out_checksum = nullptr)
{
auto check_split = Split(sp, '#');
if (check_split.size() > 2) {
error = "Multiple '#' symbols";
return false;
}
if (check_split.size() == 1 && require_checksum){
error = "Missing checksum";
return false;
}
if (check_split.size() == 2) {
if (check_split[1].size() != 8) {
error = strprintf("Expected 8 character checksum, not %u characters", check_split[1].size());
return false;
}
}
auto checksum = DescriptorChecksum(check_split[0]);
if (checksum.empty()) {
error = "Invalid characters in payload";
return false;
}
if (check_split.size() == 2) {
if (!std::equal(checksum.begin(), checksum.end(), check_split[1].begin())) {
error = strprintf("Provided checksum '%s' does not match computed checksum '%s'", std::string(check_split[1].begin(), check_split[1].end()), checksum);
return false;
}
}
if (out_checksum) *out_checksum = std::move(checksum);
sp = check_split[0];
return true;
}
std::vector<std::unique_ptr<Descriptor>> Parse(const std::string& descriptor, FlatSigningProvider& out, std::string& error, bool require_checksum)
{
Span<const char> sp{descriptor};
if (!CheckChecksum(sp, require_checksum, error)) return {};
uint32_t key_exp_index = 0;
auto ret = ParseScript(key_exp_index, sp, ParseScriptContext::TOP, out, error);
if (sp.size() == 0 && !ret.empty()) {
std::vector<std::unique_ptr<Descriptor>> descs;
descs.reserve(ret.size());
for (auto& r : ret) {
descs.emplace_back(std::unique_ptr<Descriptor>(std::move(r)));
}
return descs;
}
return {};
}
std::string GetDescriptorChecksum(const std::string& descriptor)
{
std::string ret;
std::string error;
Span<const char> sp{descriptor};
if (!CheckChecksum(sp, false, error, &ret)) return "";
return ret;
}
std::unique_ptr<Descriptor> InferDescriptor(const CScript& script, const SigningProvider& provider)
{
return InferScript(script, ParseScriptContext::TOP, provider);
}
uint256 DescriptorID(const Descriptor& desc)
{
std::string desc_str = desc.ToString(/*compat_format=*/true);
uint256 id;
CSHA256().Write((unsigned char*)desc_str.data(), desc_str.size()).Finalize(id.begin());
return id;
}
void DescriptorCache::CacheParentExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub)
{
m_parent_xpubs[key_exp_pos] = xpub;
}
void DescriptorCache::CacheDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, const CExtPubKey& xpub)
{
auto& xpubs = m_derived_xpubs[key_exp_pos];
xpubs[der_index] = xpub;
}
void DescriptorCache::CacheLastHardenedExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub)
{
m_last_hardened_xpubs[key_exp_pos] = xpub;
}
bool DescriptorCache::GetCachedParentExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const
{
const auto& it = m_parent_xpubs.find(key_exp_pos);
if (it == m_parent_xpubs.end()) return false;
xpub = it->second;
return true;
}
bool DescriptorCache::GetCachedDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, CExtPubKey& xpub) const
{
const auto& key_exp_it = m_derived_xpubs.find(key_exp_pos);
if (key_exp_it == m_derived_xpubs.end()) return false;
const auto& der_it = key_exp_it->second.find(der_index);
if (der_it == key_exp_it->second.end()) return false;
xpub = der_it->second;
return true;
}
bool DescriptorCache::GetCachedLastHardenedExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const
{
const auto& it = m_last_hardened_xpubs.find(key_exp_pos);
if (it == m_last_hardened_xpubs.end()) return false;
xpub = it->second;
return true;
}
DescriptorCache DescriptorCache::MergeAndDiff(const DescriptorCache& other)
{
DescriptorCache diff;
for (const auto& parent_xpub_pair : other.GetCachedParentExtPubKeys()) {
CExtPubKey xpub;
if (GetCachedParentExtPubKey(parent_xpub_pair.first, xpub)) {
if (xpub != parent_xpub_pair.second) {
throw std::runtime_error(std::string(__func__) + ": New cached parent xpub does not match already cached parent xpub");
}
continue;
}
CacheParentExtPubKey(parent_xpub_pair.first, parent_xpub_pair.second);
diff.CacheParentExtPubKey(parent_xpub_pair.first, parent_xpub_pair.second);
}
for (const auto& derived_xpub_map_pair : other.GetCachedDerivedExtPubKeys()) {
for (const auto& derived_xpub_pair : derived_xpub_map_pair.second) {
CExtPubKey xpub;
if (GetCachedDerivedExtPubKey(derived_xpub_map_pair.first, derived_xpub_pair.first, xpub)) {
if (xpub != derived_xpub_pair.second) {
throw std::runtime_error(std::string(__func__) + ": New cached derived xpub does not match already cached derived xpub");
}
continue;
}
CacheDerivedExtPubKey(derived_xpub_map_pair.first, derived_xpub_pair.first, derived_xpub_pair.second);
diff.CacheDerivedExtPubKey(derived_xpub_map_pair.first, derived_xpub_pair.first, derived_xpub_pair.second);
}
}
for (const auto& lh_xpub_pair : other.GetCachedLastHardenedExtPubKeys()) {
CExtPubKey xpub;
if (GetCachedLastHardenedExtPubKey(lh_xpub_pair.first, xpub)) {
if (xpub != lh_xpub_pair.second) {
throw std::runtime_error(std::string(__func__) + ": New cached last hardened xpub does not match already cached last hardened xpub");
}
continue;
}
CacheLastHardenedExtPubKey(lh_xpub_pair.first, lh_xpub_pair.second);
diff.CacheLastHardenedExtPubKey(lh_xpub_pair.first, lh_xpub_pair.second);
}
return diff;
}
ExtPubKeyMap DescriptorCache::GetCachedParentExtPubKeys() const
{
return m_parent_xpubs;
}
std::unordered_map<uint32_t, ExtPubKeyMap> DescriptorCache::GetCachedDerivedExtPubKeys() const
{
return m_derived_xpubs;
}
ExtPubKeyMap DescriptorCache::GetCachedLastHardenedExtPubKeys() const
{
return m_last_hardened_xpubs;
}
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