1 // Copyright (c) 2018-2020 The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5 #include <script/descriptor.h>
6
7 #include <key_io.h>
8 #include <pubkey.h>
9 #include <script/script.h>
10 #include <script/standard.h>
11
12 #include <span.h>
13 #include <util/bip32.h>
14 #include <util/spanparsing.h>
15 #include <util/system.h>
16 #include <util/strencodings.h>
17 #include <util/vector.h>
18
19 #include <memory>
20 #include <optional>
21 #include <string>
22 #include <vector>
23
24 namespace {
25
26 ////////////////////////////////////////////////////////////////////////////
27 // Checksum //
28 ////////////////////////////////////////////////////////////////////////////
29
30 // This section implements a checksum algorithm for descriptors with the
31 // following properties:
32 // * Mistakes in a descriptor string are measured in "symbol errors". The higher
33 // the number of symbol errors, the harder it is to detect:
34 // * An error substituting a character from 0123456789()[],'/*abcdefgh@:$%{} for
35 // another in that set always counts as 1 symbol error.
36 // * Note that hex encoded keys are covered by these characters. Xprvs and
37 // xpubs use other characters too, but already have their own checksum
38 // mechanism.
39 // * Function names like "multi()" use other characters, but mistakes in
40 // these would generally result in an unparsable descriptor.
41 // * A case error always counts as 1 symbol error.
42 // * Any other 1 character substitution error counts as 1 or 2 symbol errors.
43 // * Any 1 symbol error is always detected.
44 // * Any 2 or 3 symbol error in a descriptor of up to 49154 characters is always detected.
45 // * Any 4 symbol error in a descriptor of up to 507 characters is always detected.
46 // * Any 5 symbol error in a descriptor of up to 77 characters is always detected.
47 // * Is optimized to minimize the chance a 5 symbol error in a descriptor up to 387 characters is undetected
48 // * Random errors have a chance of 1 in 2**40 of being undetected.
49 //
50 // These properties are achieved by expanding every group of 3 (non checksum) characters into
51 // 4 GF(32) symbols, over which a cyclic code is defined.
52
53 /*
54 * Interprets c as 8 groups of 5 bits which are the coefficients of a degree 8 polynomial over GF(32),
55 * multiplies that polynomial by x, computes its remainder modulo a generator, and adds the constant term val.
56 *
57 * 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}.
58 * It is chosen to define an cyclic error detecting code which is selected by:
59 * - Starting from all BCH codes over GF(32) of degree 8 and below, which by construction guarantee detecting
60 * 3 errors in windows up to 19000 symbols.
61 * - Taking all those generators, and for degree 7 ones, extend them to degree 8 by adding all degree-1 factors.
62 * - Selecting just the set of generators that guarantee detecting 4 errors in a window of length 512.
63 * - Selecting one of those with best worst-case behavior for 5 errors in windows of length up to 512.
64 *
65 * The generator and the constants to implement it can be verified using this Sage code:
66 * B = GF(2) # Binary field
67 * BP.<b> = B[] # Polynomials over the binary field
68 * F_mod = b**5 + b**3 + 1
69 * F.<f> = GF(32, modulus=F_mod, repr='int') # GF(32) definition
70 * FP.<x> = F[] # Polynomials over GF(32)
71 * E_mod = x**3 + x + F.fetch_int(8)
72 * E.<e> = F.extension(E_mod) # Extension field definition
73 * alpha = e**2743 # Choice of an element in extension field
74 * for p in divisors(E.order() - 1): # Verify alpha has order 32767.
75 * assert((alpha**p == 1) == (p % 32767 == 0))
76 * G = lcm([(alpha**i).minpoly() for i in [1056,1057,1058]] + [x + 1])
77 * print(G) # Print out the generator
78 * for i in [1,2,4,8,16]: # Print out {1,2,4,8,16}*(G mod x^8), packed in hex integers.
79 * v = 0
80 * for coef in reversed((F.fetch_int(i)*(G % x**8)).coefficients(sparse=True)):
81 * v = v*32 + coef.integer_representation()
82 * print("0x%x" % v)
83 */
PolyMod(uint64_t c,int val)84 uint64_t PolyMod(uint64_t c, int val)
85 {
86 uint8_t c0 = c >> 35;
87 c = ((c & 0x7ffffffff) << 5) ^ val;
88 if (c0 & 1) c ^= 0xf5dee51989;
89 if (c0 & 2) c ^= 0xa9fdca3312;
90 if (c0 & 4) c ^= 0x1bab10e32d;
91 if (c0 & 8) c ^= 0x3706b1677a;
92 if (c0 & 16) c ^= 0x644d626ffd;
93 return c;
94 }
95
DescriptorChecksum(const Span<const char> & span)96 std::string DescriptorChecksum(const Span<const char>& span)
97 {
98 /** A character set designed such that:
99 * - The most common 'unprotected' descriptor characters (hex, keypaths) are in the first group of 32.
100 * - Case errors cause an offset that's a multiple of 32.
101 * - As many alphabetic characters are in the same group (while following the above restrictions).
102 *
103 * If p(x) gives the position of a character c in this character set, every group of 3 characters
104 * (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).
105 * This means that changes that only affect the lower 5 bits of the position, or only the higher 2 bits, will just
106 * affect a single symbol.
107 *
108 * As a result, within-group-of-32 errors count as 1 symbol, as do cross-group errors that don't affect
109 * the position within the groups.
110 */
111 static std::string INPUT_CHARSET =
112 "0123456789()[],'/*abcdefgh@:$%{}"
113 "IJKLMNOPQRSTUVWXYZ&+-.;<=>?!^_|~"
114 "ijklmnopqrstuvwxyzABCDEFGH`#\"\\ ";
115
116 /** The character set for the checksum itself (same as bech32). */
117 static std::string CHECKSUM_CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l";
118
119 uint64_t c = 1;
120 int cls = 0;
121 int clscount = 0;
122 for (auto ch : span) {
123 auto pos = INPUT_CHARSET.find(ch);
124 if (pos == std::string::npos) return "";
125 c = PolyMod(c, pos & 31); // Emit a symbol for the position inside the group, for every character.
126 cls = cls * 3 + (pos >> 5); // Accumulate the group numbers
127 if (++clscount == 3) {
128 // Emit an extra symbol representing the group numbers, for every 3 characters.
129 c = PolyMod(c, cls);
130 cls = 0;
131 clscount = 0;
132 }
133 }
134 if (clscount > 0) c = PolyMod(c, cls);
135 for (int j = 0; j < 8; ++j) c = PolyMod(c, 0); // Shift further to determine the checksum.
136 c ^= 1; // Prevent appending zeroes from not affecting the checksum.
137
138 std::string ret(8, ' ');
139 for (int j = 0; j < 8; ++j) ret[j] = CHECKSUM_CHARSET[(c >> (5 * (7 - j))) & 31];
140 return ret;
141 }
142
AddChecksum(const std::string & str)143 std::string AddChecksum(const std::string& str) { return str + "#" + DescriptorChecksum(str); }
144
145 ////////////////////////////////////////////////////////////////////////////
146 // Internal representation //
147 ////////////////////////////////////////////////////////////////////////////
148
149 typedef std::vector<uint32_t> KeyPath;
150
151 /** Interface for public key objects in descriptors. */
152 struct PubkeyProvider
153 {
154 protected:
155 //! Index of this key expression in the descriptor
156 //! E.g. If this PubkeyProvider is key1 in multi(2, key1, key2, key3), then m_expr_index = 0
157 uint32_t m_expr_index;
158
159 public:
PubkeyProvider__anonaf76fbc70111::PubkeyProvider160 explicit PubkeyProvider(uint32_t exp_index) : m_expr_index(exp_index) {}
161
162 virtual ~PubkeyProvider() = default;
163
164 /** Derive a public key.
165 * read_cache is the cache to read keys from (if not nullptr)
166 * write_cache is the cache to write keys to (if not nullptr)
167 * Caches are not exclusive but this is not tested. Currently we use them exclusively
168 */
169 virtual bool GetPubKey(int pos, const SigningProvider& arg, CPubKey& key, KeyOriginInfo& info, const DescriptorCache* read_cache = nullptr, DescriptorCache* write_cache = nullptr) const = 0;
170
171 /** Whether this represent multiple public keys at different positions. */
172 virtual bool IsRange() const = 0;
173
174 /** Get the size of the generated public key(s) in bytes (33 or 65). */
175 virtual size_t GetSize() const = 0;
176
177 /** Get the descriptor string form. */
178 virtual std::string ToString() const = 0;
179
180 /** Get the descriptor string form including private data (if available in arg). */
181 virtual bool ToPrivateString(const SigningProvider& arg, std::string& out) const = 0;
182
183 /** Get the descriptor string form with the xpub at the last hardened derivation */
184 virtual bool ToNormalizedString(const SigningProvider& arg, std::string& out, const DescriptorCache* cache = nullptr) const = 0;
185
186 /** Derive a private key, if private data is available in arg. */
187 virtual bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const = 0;
188 };
189
190 class OriginPubkeyProvider final : public PubkeyProvider
191 {
192 KeyOriginInfo m_origin;
193 std::unique_ptr<PubkeyProvider> m_provider;
194
OriginString() const195 std::string OriginString() const
196 {
197 return HexStr(m_origin.fingerprint) + FormatHDKeypath(m_origin.path);
198 }
199
200 public:
OriginPubkeyProvider(uint32_t exp_index,KeyOriginInfo info,std::unique_ptr<PubkeyProvider> provider)201 OriginPubkeyProvider(uint32_t exp_index, KeyOriginInfo info, std::unique_ptr<PubkeyProvider> provider) : PubkeyProvider(exp_index), m_origin(std::move(info)), m_provider(std::move(provider)) {}
GetPubKey(int pos,const SigningProvider & arg,CPubKey & key,KeyOriginInfo & info,const DescriptorCache * read_cache=nullptr,DescriptorCache * write_cache=nullptr) const202 bool GetPubKey(int pos, const SigningProvider& arg, CPubKey& key, KeyOriginInfo& info, const DescriptorCache* read_cache = nullptr, DescriptorCache* write_cache = nullptr) const override
203 {
204 if (!m_provider->GetPubKey(pos, arg, key, info, read_cache, write_cache)) return false;
205 std::copy(std::begin(m_origin.fingerprint), std::end(m_origin.fingerprint), info.fingerprint);
206 info.path.insert(info.path.begin(), m_origin.path.begin(), m_origin.path.end());
207 return true;
208 }
IsRange() const209 bool IsRange() const override { return m_provider->IsRange(); }
GetSize() const210 size_t GetSize() const override { return m_provider->GetSize(); }
ToString() const211 std::string ToString() const override { return "[" + OriginString() + "]" + m_provider->ToString(); }
ToPrivateString(const SigningProvider & arg,std::string & ret) const212 bool ToPrivateString(const SigningProvider& arg, std::string& ret) const override
213 {
214 std::string sub;
215 if (!m_provider->ToPrivateString(arg, sub)) return false;
216 ret = "[" + OriginString() + "]" + std::move(sub);
217 return true;
218 }
ToNormalizedString(const SigningProvider & arg,std::string & ret,const DescriptorCache * cache) const219 bool ToNormalizedString(const SigningProvider& arg, std::string& ret, const DescriptorCache* cache) const override
220 {
221 std::string sub;
222 if (!m_provider->ToNormalizedString(arg, sub, cache)) return false;
223 // If m_provider is a BIP32PubkeyProvider, we may get a string formatted like a OriginPubkeyProvider
224 // In that case, we need to strip out the leading square bracket and fingerprint from the substring,
225 // and append that to our own origin string.
226 if (sub[0] == '[') {
227 sub = sub.substr(9);
228 ret = "[" + OriginString() + std::move(sub);
229 } else {
230 ret = "[" + OriginString() + "]" + std::move(sub);
231 }
232 return true;
233 }
GetPrivKey(int pos,const SigningProvider & arg,CKey & key) const234 bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const override
235 {
236 return m_provider->GetPrivKey(pos, arg, key);
237 }
238 };
239
240 /** An object representing a parsed constant public key in a descriptor. */
241 class ConstPubkeyProvider final : public PubkeyProvider
242 {
243 CPubKey m_pubkey;
244 bool m_xonly;
245
246 public:
ConstPubkeyProvider(uint32_t exp_index,const CPubKey & pubkey,bool xonly)247 ConstPubkeyProvider(uint32_t exp_index, const CPubKey& pubkey, bool xonly) : PubkeyProvider(exp_index), m_pubkey(pubkey), m_xonly(xonly) {}
GetPubKey(int pos,const SigningProvider & arg,CPubKey & key,KeyOriginInfo & info,const DescriptorCache * read_cache=nullptr,DescriptorCache * write_cache=nullptr) const248 bool GetPubKey(int pos, const SigningProvider& arg, CPubKey& key, KeyOriginInfo& info, const DescriptorCache* read_cache = nullptr, DescriptorCache* write_cache = nullptr) const override
249 {
250 key = m_pubkey;
251 info.path.clear();
252 CKeyID keyid = m_pubkey.GetID();
253 std::copy(keyid.begin(), keyid.begin() + sizeof(info.fingerprint), info.fingerprint);
254 return true;
255 }
IsRange() const256 bool IsRange() const override { return false; }
GetSize() const257 size_t GetSize() const override { return m_pubkey.size(); }
ToString() const258 std::string ToString() const override { return m_xonly ? HexStr(m_pubkey).substr(2) : HexStr(m_pubkey); }
ToPrivateString(const SigningProvider & arg,std::string & ret) const259 bool ToPrivateString(const SigningProvider& arg, std::string& ret) const override
260 {
261 CKey key;
262 if (!arg.GetKey(m_pubkey.GetID(), key)) return false;
263 ret = EncodeSecret(key);
264 return true;
265 }
ToNormalizedString(const SigningProvider & arg,std::string & ret,const DescriptorCache * cache) const266 bool ToNormalizedString(const SigningProvider& arg, std::string& ret, const DescriptorCache* cache) const override
267 {
268 ret = ToString();
269 return true;
270 }
GetPrivKey(int pos,const SigningProvider & arg,CKey & key) const271 bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const override
272 {
273 return arg.GetKey(m_pubkey.GetID(), key);
274 }
275 };
276
277 enum class DeriveType {
278 NO,
279 UNHARDENED,
280 HARDENED,
281 };
282
283 /** An object representing a parsed extended public key in a descriptor. */
284 class BIP32PubkeyProvider final : public PubkeyProvider
285 {
286 // Root xpub, path, and final derivation step type being used, if any
287 CExtPubKey m_root_extkey;
288 KeyPath m_path;
289 DeriveType m_derive;
290
GetExtKey(const SigningProvider & arg,CExtKey & ret) const291 bool GetExtKey(const SigningProvider& arg, CExtKey& ret) const
292 {
293 CKey key;
294 if (!arg.GetKey(m_root_extkey.pubkey.GetID(), key)) return false;
295 ret.nDepth = m_root_extkey.nDepth;
296 std::copy(m_root_extkey.vchFingerprint, m_root_extkey.vchFingerprint + sizeof(ret.vchFingerprint), ret.vchFingerprint);
297 ret.nChild = m_root_extkey.nChild;
298 ret.chaincode = m_root_extkey.chaincode;
299 ret.key = key;
300 return true;
301 }
302
303 // Derives the last xprv
GetDerivedExtKey(const SigningProvider & arg,CExtKey & xprv,CExtKey & last_hardened) const304 bool GetDerivedExtKey(const SigningProvider& arg, CExtKey& xprv, CExtKey& last_hardened) const
305 {
306 if (!GetExtKey(arg, xprv)) return false;
307 for (auto entry : m_path) {
308 xprv.Derive(xprv, entry);
309 if (entry >> 31) {
310 last_hardened = xprv;
311 }
312 }
313 return true;
314 }
315
IsHardened() const316 bool IsHardened() const
317 {
318 if (m_derive == DeriveType::HARDENED) return true;
319 for (auto entry : m_path) {
320 if (entry >> 31) return true;
321 }
322 return false;
323 }
324
325 public:
BIP32PubkeyProvider(uint32_t exp_index,const CExtPubKey & extkey,KeyPath path,DeriveType derive)326 BIP32PubkeyProvider(uint32_t exp_index, const CExtPubKey& extkey, KeyPath path, DeriveType derive) : PubkeyProvider(exp_index), m_root_extkey(extkey), m_path(std::move(path)), m_derive(derive) {}
IsRange() const327 bool IsRange() const override { return m_derive != DeriveType::NO; }
GetSize() const328 size_t GetSize() const override { return 33; }
GetPubKey(int pos,const SigningProvider & arg,CPubKey & key_out,KeyOriginInfo & final_info_out,const DescriptorCache * read_cache=nullptr,DescriptorCache * write_cache=nullptr) const329 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
330 {
331 // Info of parent of the to be derived pubkey
332 KeyOriginInfo parent_info;
333 CKeyID keyid = m_root_extkey.pubkey.GetID();
334 std::copy(keyid.begin(), keyid.begin() + sizeof(parent_info.fingerprint), parent_info.fingerprint);
335 parent_info.path = m_path;
336
337 // Info of the derived key itself which is copied out upon successful completion
338 KeyOriginInfo final_info_out_tmp = parent_info;
339 if (m_derive == DeriveType::UNHARDENED) final_info_out_tmp.path.push_back((uint32_t)pos);
340 if (m_derive == DeriveType::HARDENED) final_info_out_tmp.path.push_back(((uint32_t)pos) | 0x80000000L);
341
342 // Derive keys or fetch them from cache
343 CExtPubKey final_extkey = m_root_extkey;
344 CExtPubKey parent_extkey = m_root_extkey;
345 CExtPubKey last_hardened_extkey;
346 bool der = true;
347 if (read_cache) {
348 if (!read_cache->GetCachedDerivedExtPubKey(m_expr_index, pos, final_extkey)) {
349 if (m_derive == DeriveType::HARDENED) return false;
350 // Try to get the derivation parent
351 if (!read_cache->GetCachedParentExtPubKey(m_expr_index, parent_extkey)) return false;
352 final_extkey = parent_extkey;
353 if (m_derive == DeriveType::UNHARDENED) der = parent_extkey.Derive(final_extkey, pos);
354 }
355 } else if (IsHardened()) {
356 CExtKey xprv;
357 CExtKey lh_xprv;
358 if (!GetDerivedExtKey(arg, xprv, lh_xprv)) return false;
359 parent_extkey = xprv.Neuter();
360 if (m_derive == DeriveType::UNHARDENED) der = xprv.Derive(xprv, pos);
361 if (m_derive == DeriveType::HARDENED) der = xprv.Derive(xprv, pos | 0x80000000UL);
362 final_extkey = xprv.Neuter();
363 if (lh_xprv.key.IsValid()) {
364 last_hardened_extkey = lh_xprv.Neuter();
365 }
366 } else {
367 for (auto entry : m_path) {
368 der = parent_extkey.Derive(parent_extkey, entry);
369 assert(der);
370 }
371 final_extkey = parent_extkey;
372 if (m_derive == DeriveType::UNHARDENED) der = parent_extkey.Derive(final_extkey, pos);
373 assert(m_derive != DeriveType::HARDENED);
374 }
375 assert(der);
376
377 final_info_out = final_info_out_tmp;
378 key_out = final_extkey.pubkey;
379
380 if (write_cache) {
381 // Only cache parent if there is any unhardened derivation
382 if (m_derive != DeriveType::HARDENED) {
383 write_cache->CacheParentExtPubKey(m_expr_index, parent_extkey);
384 // Cache last hardened xpub if we have it
385 if (last_hardened_extkey.pubkey.IsValid()) {
386 write_cache->CacheLastHardenedExtPubKey(m_expr_index, last_hardened_extkey);
387 }
388 } else if (final_info_out.path.size() > 0) {
389 write_cache->CacheDerivedExtPubKey(m_expr_index, pos, final_extkey);
390 }
391 }
392
393 return true;
394 }
ToString() const395 std::string ToString() const override
396 {
397 std::string ret = EncodeExtPubKey(m_root_extkey) + FormatHDKeypath(m_path);
398 if (IsRange()) {
399 ret += "/*";
400 if (m_derive == DeriveType::HARDENED) ret += '\'';
401 }
402 return ret;
403 }
ToPrivateString(const SigningProvider & arg,std::string & out) const404 bool ToPrivateString(const SigningProvider& arg, std::string& out) const override
405 {
406 CExtKey key;
407 if (!GetExtKey(arg, key)) return false;
408 out = EncodeExtKey(key) + FormatHDKeypath(m_path);
409 if (IsRange()) {
410 out += "/*";
411 if (m_derive == DeriveType::HARDENED) out += '\'';
412 }
413 return true;
414 }
ToNormalizedString(const SigningProvider & arg,std::string & out,const DescriptorCache * cache) const415 bool ToNormalizedString(const SigningProvider& arg, std::string& out, const DescriptorCache* cache) const override
416 {
417 // For hardened derivation type, just return the typical string, nothing to normalize
418 if (m_derive == DeriveType::HARDENED) {
419 out = ToString();
420 return true;
421 }
422 // Step backwards to find the last hardened step in the path
423 int i = (int)m_path.size() - 1;
424 for (; i >= 0; --i) {
425 if (m_path.at(i) >> 31) {
426 break;
427 }
428 }
429 // Either no derivation or all unhardened derivation
430 if (i == -1) {
431 out = ToString();
432 return true;
433 }
434 // Get the path to the last hardened stup
435 KeyOriginInfo origin;
436 int k = 0;
437 for (; k <= i; ++k) {
438 // Add to the path
439 origin.path.push_back(m_path.at(k));
440 }
441 // Build the remaining path
442 KeyPath end_path;
443 for (; k < (int)m_path.size(); ++k) {
444 end_path.push_back(m_path.at(k));
445 }
446 // Get the fingerprint
447 CKeyID id = m_root_extkey.pubkey.GetID();
448 std::copy(id.begin(), id.begin() + 4, origin.fingerprint);
449
450 CExtPubKey xpub;
451 CExtKey lh_xprv;
452 // If we have the cache, just get the parent xpub
453 if (cache != nullptr) {
454 cache->GetCachedLastHardenedExtPubKey(m_expr_index, xpub);
455 }
456 if (!xpub.pubkey.IsValid()) {
457 // Cache miss, or nor cache, or need privkey
458 CExtKey xprv;
459 if (!GetDerivedExtKey(arg, xprv, lh_xprv)) return false;
460 xpub = lh_xprv.Neuter();
461 }
462 assert(xpub.pubkey.IsValid());
463
464 // Build the string
465 std::string origin_str = HexStr(origin.fingerprint) + FormatHDKeypath(origin.path);
466 out = "[" + origin_str + "]" + EncodeExtPubKey(xpub) + FormatHDKeypath(end_path);
467 if (IsRange()) {
468 out += "/*";
469 assert(m_derive == DeriveType::UNHARDENED);
470 }
471 return true;
472 }
GetPrivKey(int pos,const SigningProvider & arg,CKey & key) const473 bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const override
474 {
475 CExtKey extkey;
476 CExtKey dummy;
477 if (!GetDerivedExtKey(arg, extkey, dummy)) return false;
478 if (m_derive == DeriveType::UNHARDENED) extkey.Derive(extkey, pos);
479 if (m_derive == DeriveType::HARDENED) extkey.Derive(extkey, pos | 0x80000000UL);
480 key = extkey.key;
481 return true;
482 }
483 };
484
485 /** Base class for all Descriptor implementations. */
486 class DescriptorImpl : public Descriptor
487 {
488 //! Public key arguments for this descriptor (size 1 for PK, PKH, WPKH; any size for Multisig).
489 const std::vector<std::unique_ptr<PubkeyProvider>> m_pubkey_args;
490 //! The string name of the descriptor function.
491 const std::string m_name;
492
493 protected:
494 //! The sub-descriptor arguments (empty for everything but SH and WSH).
495 //! In doc/descriptors.m this is referred to as SCRIPT expressions sh(SCRIPT)
496 //! and wsh(SCRIPT), and distinct from KEY expressions and ADDR expressions.
497 //! Subdescriptors can only ever generate a single script.
498 const std::vector<std::unique_ptr<DescriptorImpl>> m_subdescriptor_args;
499
500 //! Return a serialization of anything except pubkey and script arguments, to be prepended to those.
ToStringExtra() const501 virtual std::string ToStringExtra() const { return ""; }
502
503 /** A helper function to construct the scripts for this descriptor.
504 *
505 * This function is invoked once by ExpandHelper.
506 *
507 * @param pubkeys The evaluations of the m_pubkey_args field.
508 * @param scripts The evaluations of m_subdescriptor_args (one for each m_subdescriptor_args element).
509 * @param out A FlatSigningProvider to put scripts or public keys in that are necessary to the solver.
510 * The origin info of the provided pubkeys is automatically added.
511 * @return A vector with scriptPubKeys for this descriptor.
512 */
513 virtual std::vector<CScript> MakeScripts(const std::vector<CPubKey>& pubkeys, Span<const CScript> scripts, FlatSigningProvider& out) const = 0;
514
515 public:
DescriptorImpl(std::vector<std::unique_ptr<PubkeyProvider>> pubkeys,const std::string & name)516 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)517 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)518 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)) {}
519
520 enum class StringType
521 {
522 PUBLIC,
523 PRIVATE,
524 NORMALIZED,
525 };
526
IsSolvable() const527 bool IsSolvable() const override
528 {
529 for (const auto& arg : m_subdescriptor_args) {
530 if (!arg->IsSolvable()) return false;
531 }
532 return true;
533 }
534
IsRange() const535 bool IsRange() const final
536 {
537 for (const auto& pubkey : m_pubkey_args) {
538 if (pubkey->IsRange()) return true;
539 }
540 for (const auto& arg : m_subdescriptor_args) {
541 if (arg->IsRange()) return true;
542 }
543 return false;
544 }
545
ToStringSubScriptHelper(const SigningProvider * arg,std::string & ret,const StringType type,const DescriptorCache * cache=nullptr) const546 virtual bool ToStringSubScriptHelper(const SigningProvider* arg, std::string& ret, const StringType type, const DescriptorCache* cache = nullptr) const
547 {
548 size_t pos = 0;
549 for (const auto& scriptarg : m_subdescriptor_args) {
550 if (pos++) ret += ",";
551 std::string tmp;
552 if (!scriptarg->ToStringHelper(arg, tmp, type, cache)) return false;
553 ret += std::move(tmp);
554 }
555 return true;
556 }
557
ToStringHelper(const SigningProvider * arg,std::string & out,const StringType type,const DescriptorCache * cache=nullptr) const558 bool ToStringHelper(const SigningProvider* arg, std::string& out, const StringType type, const DescriptorCache* cache = nullptr) const
559 {
560 std::string extra = ToStringExtra();
561 size_t pos = extra.size() > 0 ? 1 : 0;
562 std::string ret = m_name + "(" + extra;
563 for (const auto& pubkey : m_pubkey_args) {
564 if (pos++) ret += ",";
565 std::string tmp;
566 switch (type) {
567 case StringType::NORMALIZED:
568 if (!pubkey->ToNormalizedString(*arg, tmp, cache)) return false;
569 break;
570 case StringType::PRIVATE:
571 if (!pubkey->ToPrivateString(*arg, tmp)) return false;
572 break;
573 case StringType::PUBLIC:
574 tmp = pubkey->ToString();
575 break;
576 }
577 ret += std::move(tmp);
578 }
579 std::string subscript;
580 if (!ToStringSubScriptHelper(arg, subscript, type, cache)) return false;
581 if (pos && subscript.size()) ret += ',';
582 out = std::move(ret) + std::move(subscript) + ")";
583 return true;
584 }
585
ToString() const586 std::string ToString() const final
587 {
588 std::string ret;
589 ToStringHelper(nullptr, ret, StringType::PUBLIC);
590 return AddChecksum(ret);
591 }
592
ToPrivateString(const SigningProvider & arg,std::string & out) const593 bool ToPrivateString(const SigningProvider& arg, std::string& out) const final
594 {
595 bool ret = ToStringHelper(&arg, out, StringType::PRIVATE);
596 out = AddChecksum(out);
597 return ret;
598 }
599
ToNormalizedString(const SigningProvider & arg,std::string & out,const DescriptorCache * cache) const600 bool ToNormalizedString(const SigningProvider& arg, std::string& out, const DescriptorCache* cache) const override final
601 {
602 bool ret = ToStringHelper(&arg, out, StringType::NORMALIZED, cache);
603 out = AddChecksum(out);
604 return ret;
605 }
606
ExpandHelper(int pos,const SigningProvider & arg,const DescriptorCache * read_cache,std::vector<CScript> & output_scripts,FlatSigningProvider & out,DescriptorCache * write_cache) const607 bool ExpandHelper(int pos, const SigningProvider& arg, const DescriptorCache* read_cache, std::vector<CScript>& output_scripts, FlatSigningProvider& out, DescriptorCache* write_cache) const
608 {
609 std::vector<std::pair<CPubKey, KeyOriginInfo>> entries;
610 entries.reserve(m_pubkey_args.size());
611
612 // Construct temporary data in `entries`, `subscripts`, and `subprovider` to avoid producing output in case of failure.
613 for (const auto& p : m_pubkey_args) {
614 entries.emplace_back();
615 if (!p->GetPubKey(pos, arg, entries.back().first, entries.back().second, read_cache, write_cache)) return false;
616 }
617 std::vector<CScript> subscripts;
618 FlatSigningProvider subprovider;
619 for (const auto& subarg : m_subdescriptor_args) {
620 std::vector<CScript> outscripts;
621 if (!subarg->ExpandHelper(pos, arg, read_cache, outscripts, subprovider, write_cache)) return false;
622 assert(outscripts.size() == 1);
623 subscripts.emplace_back(std::move(outscripts[0]));
624 }
625 out = Merge(std::move(out), std::move(subprovider));
626
627 std::vector<CPubKey> pubkeys;
628 pubkeys.reserve(entries.size());
629 for (auto& entry : entries) {
630 pubkeys.push_back(entry.first);
631 out.origins.emplace(entry.first.GetID(), std::make_pair<CPubKey, KeyOriginInfo>(CPubKey(entry.first), std::move(entry.second)));
632 }
633
634 output_scripts = MakeScripts(pubkeys, MakeSpan(subscripts), out);
635 return true;
636 }
637
Expand(int pos,const SigningProvider & provider,std::vector<CScript> & output_scripts,FlatSigningProvider & out,DescriptorCache * write_cache=nullptr) const638 bool Expand(int pos, const SigningProvider& provider, std::vector<CScript>& output_scripts, FlatSigningProvider& out, DescriptorCache* write_cache = nullptr) const final
639 {
640 return ExpandHelper(pos, provider, nullptr, output_scripts, out, write_cache);
641 }
642
ExpandFromCache(int pos,const DescriptorCache & read_cache,std::vector<CScript> & output_scripts,FlatSigningProvider & out) const643 bool ExpandFromCache(int pos, const DescriptorCache& read_cache, std::vector<CScript>& output_scripts, FlatSigningProvider& out) const final
644 {
645 return ExpandHelper(pos, DUMMY_SIGNING_PROVIDER, &read_cache, output_scripts, out, nullptr);
646 }
647
ExpandPrivate(int pos,const SigningProvider & provider,FlatSigningProvider & out) const648 void ExpandPrivate(int pos, const SigningProvider& provider, FlatSigningProvider& out) const final
649 {
650 for (const auto& p : m_pubkey_args) {
651 CKey key;
652 if (!p->GetPrivKey(pos, provider, key)) continue;
653 out.keys.emplace(key.GetPubKey().GetID(), key);
654 }
655 for (const auto& arg : m_subdescriptor_args) {
656 arg->ExpandPrivate(pos, provider, out);
657 }
658 }
659
GetOutputType() const660 std::optional<OutputType> GetOutputType() const override { return std::nullopt; }
661 };
662
663 /** A parsed addr(A) descriptor. */
664 class AddressDescriptor final : public DescriptorImpl
665 {
666 const CTxDestination m_destination;
667 protected:
ToStringExtra() const668 std::string ToStringExtra() const override { return EncodeDestination(m_destination); }
MakeScripts(const std::vector<CPubKey> &,Span<const CScript>,FlatSigningProvider &) const669 std::vector<CScript> MakeScripts(const std::vector<CPubKey>&, Span<const CScript>, FlatSigningProvider&) const override { return Vector(GetScriptForDestination(m_destination)); }
670 public:
AddressDescriptor(CTxDestination destination)671 AddressDescriptor(CTxDestination destination) : DescriptorImpl({}, "addr"), m_destination(std::move(destination)) {}
IsSolvable() const672 bool IsSolvable() const final { return false; }
673
GetOutputType() const674 std::optional<OutputType> GetOutputType() const override
675 {
676 return OutputTypeFromDestination(m_destination);
677 }
IsSingleType() const678 bool IsSingleType() const final { return true; }
679 };
680
681 /** A parsed raw(H) descriptor. */
682 class RawDescriptor final : public DescriptorImpl
683 {
684 const CScript m_script;
685 protected:
ToStringExtra() const686 std::string ToStringExtra() const override { return HexStr(m_script); }
MakeScripts(const std::vector<CPubKey> &,Span<const CScript>,FlatSigningProvider &) const687 std::vector<CScript> MakeScripts(const std::vector<CPubKey>&, Span<const CScript>, FlatSigningProvider&) const override { return Vector(m_script); }
688 public:
RawDescriptor(CScript script)689 RawDescriptor(CScript script) : DescriptorImpl({}, "raw"), m_script(std::move(script)) {}
IsSolvable() const690 bool IsSolvable() const final { return false; }
691
GetOutputType() const692 std::optional<OutputType> GetOutputType() const override
693 {
694 CTxDestination dest;
695 ExtractDestination(m_script, dest);
696 return OutputTypeFromDestination(dest);
697 }
IsSingleType() const698 bool IsSingleType() const final { return true; }
699 };
700
701 /** A parsed pk(P) descriptor. */
702 class PKDescriptor final : public DescriptorImpl
703 {
704 private:
705 const bool m_xonly;
706 protected:
MakeScripts(const std::vector<CPubKey> & keys,Span<const CScript>,FlatSigningProvider &) const707 std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider&) const override
708 {
709 if (m_xonly) {
710 CScript script = CScript() << ToByteVector(XOnlyPubKey(keys[0])) << OP_CHECKSIG;
711 return Vector(std::move(script));
712 } else {
713 return Vector(GetScriptForRawPubKey(keys[0]));
714 }
715 }
716 public:
PKDescriptor(std::unique_ptr<PubkeyProvider> prov,bool xonly=false)717 PKDescriptor(std::unique_ptr<PubkeyProvider> prov, bool xonly = false) : DescriptorImpl(Vector(std::move(prov)), "pk"), m_xonly(xonly) {}
IsSingleType() const718 bool IsSingleType() const final { return true; }
719 };
720
721 /** A parsed pkh(P) descriptor. */
722 class PKHDescriptor final : public DescriptorImpl
723 {
724 protected:
MakeScripts(const std::vector<CPubKey> & keys,Span<const CScript>,FlatSigningProvider & out) const725 std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider& out) const override
726 {
727 CKeyID id = keys[0].GetID();
728 out.pubkeys.emplace(id, keys[0]);
729 return Vector(GetScriptForDestination(PKHash(id)));
730 }
731 public:
PKHDescriptor(std::unique_ptr<PubkeyProvider> prov)732 PKHDescriptor(std::unique_ptr<PubkeyProvider> prov) : DescriptorImpl(Vector(std::move(prov)), "pkh") {}
GetOutputType() const733 std::optional<OutputType> GetOutputType() const override { return OutputType::LEGACY; }
IsSingleType() const734 bool IsSingleType() const final { return true; }
735 };
736
737 /** A parsed wpkh(P) descriptor. */
738 class WPKHDescriptor final : public DescriptorImpl
739 {
740 protected:
MakeScripts(const std::vector<CPubKey> & keys,Span<const CScript>,FlatSigningProvider & out) const741 std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider& out) const override
742 {
743 CKeyID id = keys[0].GetID();
744 out.pubkeys.emplace(id, keys[0]);
745 return Vector(GetScriptForDestination(WitnessV0KeyHash(id)));
746 }
747 public:
WPKHDescriptor(std::unique_ptr<PubkeyProvider> prov)748 WPKHDescriptor(std::unique_ptr<PubkeyProvider> prov) : DescriptorImpl(Vector(std::move(prov)), "wpkh") {}
GetOutputType() const749 std::optional<OutputType> GetOutputType() const override { return OutputType::BECH32; }
IsSingleType() const750 bool IsSingleType() const final { return true; }
751 };
752
753 /** A parsed combo(P) descriptor. */
754 class ComboDescriptor final : public DescriptorImpl
755 {
756 protected:
MakeScripts(const std::vector<CPubKey> & keys,Span<const CScript>,FlatSigningProvider & out) const757 std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider& out) const override
758 {
759 std::vector<CScript> ret;
760 CKeyID id = keys[0].GetID();
761 out.pubkeys.emplace(id, keys[0]);
762 ret.emplace_back(GetScriptForRawPubKey(keys[0])); // P2PK
763 ret.emplace_back(GetScriptForDestination(PKHash(id))); // P2PKH
764 if (keys[0].IsCompressed()) {
765 CScript p2wpkh = GetScriptForDestination(WitnessV0KeyHash(id));
766 out.scripts.emplace(CScriptID(p2wpkh), p2wpkh);
767 ret.emplace_back(p2wpkh);
768 ret.emplace_back(GetScriptForDestination(ScriptHash(p2wpkh))); // P2SH-P2WPKH
769 }
770 return ret;
771 }
772 public:
ComboDescriptor(std::unique_ptr<PubkeyProvider> prov)773 ComboDescriptor(std::unique_ptr<PubkeyProvider> prov) : DescriptorImpl(Vector(std::move(prov)), "combo") {}
IsSingleType() const774 bool IsSingleType() const final { return false; }
775 };
776
777 /** A parsed multi(...) or sortedmulti(...) descriptor */
778 class MultisigDescriptor final : public DescriptorImpl
779 {
780 const int m_threshold;
781 const bool m_sorted;
782 protected:
ToStringExtra() const783 std::string ToStringExtra() const override { return strprintf("%i", m_threshold); }
MakeScripts(const std::vector<CPubKey> & keys,Span<const CScript>,FlatSigningProvider &) const784 std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider&) const override {
785 if (m_sorted) {
786 std::vector<CPubKey> sorted_keys(keys);
787 std::sort(sorted_keys.begin(), sorted_keys.end());
788 return Vector(GetScriptForMultisig(m_threshold, sorted_keys));
789 }
790 return Vector(GetScriptForMultisig(m_threshold, keys));
791 }
792 public:
MultisigDescriptor(int threshold,std::vector<std::unique_ptr<PubkeyProvider>> providers,bool sorted=false)793 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) {}
IsSingleType() const794 bool IsSingleType() const final { return true; }
795 };
796
797 /** A parsed sh(...) descriptor. */
798 class SHDescriptor final : public DescriptorImpl
799 {
800 protected:
MakeScripts(const std::vector<CPubKey> &,Span<const CScript> scripts,FlatSigningProvider & out) const801 std::vector<CScript> MakeScripts(const std::vector<CPubKey>&, Span<const CScript> scripts, FlatSigningProvider& out) const override
802 {
803 auto ret = Vector(GetScriptForDestination(ScriptHash(scripts[0])));
804 if (ret.size()) out.scripts.emplace(CScriptID(scripts[0]), scripts[0]);
805 return ret;
806 }
807 public:
SHDescriptor(std::unique_ptr<DescriptorImpl> desc)808 SHDescriptor(std::unique_ptr<DescriptorImpl> desc) : DescriptorImpl({}, std::move(desc), "sh") {}
809
GetOutputType() const810 std::optional<OutputType> GetOutputType() const override
811 {
812 assert(m_subdescriptor_args.size() == 1);
813 if (m_subdescriptor_args[0]->GetOutputType() == OutputType::BECH32) return OutputType::P2SH_SEGWIT;
814 return OutputType::LEGACY;
815 }
IsSingleType() const816 bool IsSingleType() const final { return true; }
817 };
818
819 /** A parsed wsh(...) descriptor. */
820 class WSHDescriptor final : public DescriptorImpl
821 {
822 protected:
MakeScripts(const std::vector<CPubKey> &,Span<const CScript> scripts,FlatSigningProvider & out) const823 std::vector<CScript> MakeScripts(const std::vector<CPubKey>&, Span<const CScript> scripts, FlatSigningProvider& out) const override
824 {
825 auto ret = Vector(GetScriptForDestination(WitnessV0ScriptHash(scripts[0])));
826 if (ret.size()) out.scripts.emplace(CScriptID(scripts[0]), scripts[0]);
827 return ret;
828 }
829 public:
WSHDescriptor(std::unique_ptr<DescriptorImpl> desc)830 WSHDescriptor(std::unique_ptr<DescriptorImpl> desc) : DescriptorImpl({}, std::move(desc), "wsh") {}
GetOutputType() const831 std::optional<OutputType> GetOutputType() const override { return OutputType::BECH32; }
IsSingleType() const832 bool IsSingleType() const final { return true; }
833 };
834
835 /** A parsed tr(...) descriptor. */
836 class TRDescriptor final : public DescriptorImpl
837 {
838 std::vector<int> m_depths;
839 protected:
MakeScripts(const std::vector<CPubKey> & keys,Span<const CScript> scripts,FlatSigningProvider & out) const840 std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript> scripts, FlatSigningProvider& out) const override
841 {
842 TaprootBuilder builder;
843 assert(m_depths.size() == scripts.size());
844 for (size_t pos = 0; pos < m_depths.size(); ++pos) {
845 builder.Add(m_depths[pos], scripts[pos], TAPROOT_LEAF_TAPSCRIPT);
846 }
847 if (!builder.IsComplete()) return {};
848 assert(keys.size() == 1);
849 XOnlyPubKey xpk(keys[0]);
850 if (!xpk.IsFullyValid()) return {};
851 builder.Finalize(xpk);
852 WitnessV1Taproot output = builder.GetOutput();
853 out.tr_spenddata[output].Merge(builder.GetSpendData());
854 return Vector(GetScriptForDestination(output));
855 }
ToStringSubScriptHelper(const SigningProvider * arg,std::string & ret,const StringType type,const DescriptorCache * cache=nullptr) const856 bool ToStringSubScriptHelper(const SigningProvider* arg, std::string& ret, const StringType type, const DescriptorCache* cache = nullptr) const override
857 {
858 if (m_depths.empty()) return true;
859 std::vector<bool> path;
860 for (size_t pos = 0; pos < m_depths.size(); ++pos) {
861 if (pos) ret += ',';
862 while ((int)path.size() <= m_depths[pos]) {
863 if (path.size()) ret += '{';
864 path.push_back(false);
865 }
866 std::string tmp;
867 if (!m_subdescriptor_args[pos]->ToStringHelper(arg, tmp, type, cache)) return false;
868 ret += std::move(tmp);
869 while (!path.empty() && path.back()) {
870 if (path.size() > 1) ret += '}';
871 path.pop_back();
872 }
873 if (!path.empty()) path.back() = true;
874 }
875 return true;
876 }
877 public:
TRDescriptor(std::unique_ptr<PubkeyProvider> internal_key,std::vector<std::unique_ptr<DescriptorImpl>> descs,std::vector<int> depths)878 TRDescriptor(std::unique_ptr<PubkeyProvider> internal_key, std::vector<std::unique_ptr<DescriptorImpl>> descs, std::vector<int> depths) :
879 DescriptorImpl(Vector(std::move(internal_key)), std::move(descs), "tr"), m_depths(std::move(depths))
880 {
881 assert(m_subdescriptor_args.size() == m_depths.size());
882 }
GetOutputType() const883 std::optional<OutputType> GetOutputType() const override { return OutputType::BECH32M; }
IsSingleType() const884 bool IsSingleType() const final { return true; }
885 };
886
887 ////////////////////////////////////////////////////////////////////////////
888 // Parser //
889 ////////////////////////////////////////////////////////////////////////////
890
891 enum class ParseScriptContext {
892 TOP, //!< Top-level context (script goes directly in scriptPubKey)
893 P2SH, //!< Inside sh() (script becomes P2SH redeemScript)
894 P2WPKH, //!< Inside wpkh() (no script, pubkey only)
895 P2WSH, //!< Inside wsh() (script becomes v0 witness script)
896 P2TR, //!< Inside tr() (either internal key, or BIP342 script leaf)
897 };
898
899 /** Parse a key path, being passed a split list of elements (the first element is ignored). */
ParseKeyPath(const std::vector<Span<const char>> & split,KeyPath & out,std::string & error)900 [[nodiscard]] bool ParseKeyPath(const std::vector<Span<const char>>& split, KeyPath& out, std::string& error)
901 {
902 for (size_t i = 1; i < split.size(); ++i) {
903 Span<const char> elem = split[i];
904 bool hardened = false;
905 if (elem.size() > 0 && (elem[elem.size() - 1] == '\'' || elem[elem.size() - 1] == 'h')) {
906 elem = elem.first(elem.size() - 1);
907 hardened = true;
908 }
909 uint32_t p;
910 if (!ParseUInt32(std::string(elem.begin(), elem.end()), &p)) {
911 error = strprintf("Key path value '%s' is not a valid uint32", std::string(elem.begin(), elem.end()));
912 return false;
913 } else if (p > 0x7FFFFFFFUL) {
914 error = strprintf("Key path value %u is out of range", p);
915 return false;
916 }
917 out.push_back(p | (((uint32_t)hardened) << 31));
918 }
919 return true;
920 }
921
922 /** Parse a public key that excludes origin information. */
ParsePubkeyInner(uint32_t key_exp_index,const Span<const char> & sp,ParseScriptContext ctx,FlatSigningProvider & out,std::string & error)923 std::unique_ptr<PubkeyProvider> ParsePubkeyInner(uint32_t key_exp_index, const Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, std::string& error)
924 {
925 using namespace spanparsing;
926
927 bool permit_uncompressed = ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH;
928 auto split = Split(sp, '/');
929 std::string str(split[0].begin(), split[0].end());
930 if (str.size() == 0) {
931 error = "No key provided";
932 return nullptr;
933 }
934 if (split.size() == 1) {
935 if (IsHex(str)) {
936 std::vector<unsigned char> data = ParseHex(str);
937 CPubKey pubkey(data);
938 if (pubkey.IsFullyValid()) {
939 if (permit_uncompressed || pubkey.IsCompressed()) {
940 return std::make_unique<ConstPubkeyProvider>(key_exp_index, pubkey, false);
941 } else {
942 error = "Uncompressed keys are not allowed";
943 return nullptr;
944 }
945 } else if (data.size() == 32 && ctx == ParseScriptContext::P2TR) {
946 unsigned char fullkey[33] = {0x02};
947 std::copy(data.begin(), data.end(), fullkey + 1);
948 pubkey.Set(std::begin(fullkey), std::end(fullkey));
949 if (pubkey.IsFullyValid()) {
950 return std::make_unique<ConstPubkeyProvider>(key_exp_index, pubkey, true);
951 }
952 }
953 error = strprintf("Pubkey '%s' is invalid", str);
954 return nullptr;
955 }
956 CKey key = DecodeSecret(str);
957 if (key.IsValid()) {
958 if (permit_uncompressed || key.IsCompressed()) {
959 CPubKey pubkey = key.GetPubKey();
960 out.keys.emplace(pubkey.GetID(), key);
961 return std::make_unique<ConstPubkeyProvider>(key_exp_index, pubkey, ctx == ParseScriptContext::P2TR);
962 } else {
963 error = "Uncompressed keys are not allowed";
964 return nullptr;
965 }
966 }
967 }
968 CExtKey extkey = DecodeExtKey(str);
969 CExtPubKey extpubkey = DecodeExtPubKey(str);
970 if (!extkey.key.IsValid() && !extpubkey.pubkey.IsValid()) {
971 error = strprintf("key '%s' is not valid", str);
972 return nullptr;
973 }
974 KeyPath path;
975 DeriveType type = DeriveType::NO;
976 if (split.back() == MakeSpan("*").first(1)) {
977 split.pop_back();
978 type = DeriveType::UNHARDENED;
979 } else if (split.back() == MakeSpan("*'").first(2) || split.back() == MakeSpan("*h").first(2)) {
980 split.pop_back();
981 type = DeriveType::HARDENED;
982 }
983 if (!ParseKeyPath(split, path, error)) return nullptr;
984 if (extkey.key.IsValid()) {
985 extpubkey = extkey.Neuter();
986 out.keys.emplace(extpubkey.pubkey.GetID(), extkey.key);
987 }
988 return std::make_unique<BIP32PubkeyProvider>(key_exp_index, extpubkey, std::move(path), type);
989 }
990
991 /** Parse a public key including origin information (if enabled). */
ParsePubkey(uint32_t key_exp_index,const Span<const char> & sp,ParseScriptContext ctx,FlatSigningProvider & out,std::string & error)992 std::unique_ptr<PubkeyProvider> ParsePubkey(uint32_t key_exp_index, const Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, std::string& error)
993 {
994 using namespace spanparsing;
995
996 auto origin_split = Split(sp, ']');
997 if (origin_split.size() > 2) {
998 error = "Multiple ']' characters found for a single pubkey";
999 return nullptr;
1000 }
1001 if (origin_split.size() == 1) return ParsePubkeyInner(key_exp_index, origin_split[0], ctx, out, error);
1002 if (origin_split[0].empty() || origin_split[0][0] != '[') {
1003 error = strprintf("Key origin start '[ character expected but not found, got '%c' instead",
1004 origin_split[0].empty() ? /** empty, implies split char */ ']' : origin_split[0][0]);
1005 return nullptr;
1006 }
1007 auto slash_split = Split(origin_split[0].subspan(1), '/');
1008 if (slash_split[0].size() != 8) {
1009 error = strprintf("Fingerprint is not 4 bytes (%u characters instead of 8 characters)", slash_split[0].size());
1010 return nullptr;
1011 }
1012 std::string fpr_hex = std::string(slash_split[0].begin(), slash_split[0].end());
1013 if (!IsHex(fpr_hex)) {
1014 error = strprintf("Fingerprint '%s' is not hex", fpr_hex);
1015 return nullptr;
1016 }
1017 auto fpr_bytes = ParseHex(fpr_hex);
1018 KeyOriginInfo info;
1019 static_assert(sizeof(info.fingerprint) == 4, "Fingerprint must be 4 bytes");
1020 assert(fpr_bytes.size() == 4);
1021 std::copy(fpr_bytes.begin(), fpr_bytes.end(), info.fingerprint);
1022 if (!ParseKeyPath(slash_split, info.path, error)) return nullptr;
1023 auto provider = ParsePubkeyInner(key_exp_index, origin_split[1], ctx, out, error);
1024 if (!provider) return nullptr;
1025 return std::make_unique<OriginPubkeyProvider>(key_exp_index, std::move(info), std::move(provider));
1026 }
1027
1028 /** Parse a script in a particular context. */
ParseScript(uint32_t & key_exp_index,Span<const char> & sp,ParseScriptContext ctx,FlatSigningProvider & out,std::string & error)1029 std::unique_ptr<DescriptorImpl> ParseScript(uint32_t& key_exp_index, Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, std::string& error)
1030 {
1031 using namespace spanparsing;
1032
1033 auto expr = Expr(sp);
1034 bool sorted_multi = false;
1035 if (Func("pk", expr)) {
1036 auto pubkey = ParsePubkey(key_exp_index, expr, ctx, out, error);
1037 if (!pubkey) return nullptr;
1038 ++key_exp_index;
1039 return std::make_unique<PKDescriptor>(std::move(pubkey), ctx == ParseScriptContext::P2TR);
1040 }
1041 if ((ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH) && Func("pkh", expr)) {
1042 auto pubkey = ParsePubkey(key_exp_index, expr, ctx, out, error);
1043 if (!pubkey) return nullptr;
1044 ++key_exp_index;
1045 return std::make_unique<PKHDescriptor>(std::move(pubkey));
1046 } else if (Func("pkh", expr)) {
1047 error = "Can only have pkh at top level, in sh(), or in wsh()";
1048 return nullptr;
1049 }
1050 if (ctx == ParseScriptContext::TOP && Func("combo", expr)) {
1051 auto pubkey = ParsePubkey(key_exp_index, expr, ctx, out, error);
1052 if (!pubkey) return nullptr;
1053 ++key_exp_index;
1054 return std::make_unique<ComboDescriptor>(std::move(pubkey));
1055 } else if (Func("combo", expr)) {
1056 error = "Can only have combo() at top level";
1057 return nullptr;
1058 }
1059 if ((ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH) && ((sorted_multi = Func("sortedmulti", expr)) || Func("multi", expr))) {
1060 auto threshold = Expr(expr);
1061 uint32_t thres;
1062 std::vector<std::unique_ptr<PubkeyProvider>> providers;
1063 if (!ParseUInt32(std::string(threshold.begin(), threshold.end()), &thres)) {
1064 error = strprintf("Multi threshold '%s' is not valid", std::string(threshold.begin(), threshold.end()));
1065 return nullptr;
1066 }
1067 size_t script_size = 0;
1068 while (expr.size()) {
1069 if (!Const(",", expr)) {
1070 error = strprintf("Multi: expected ',', got '%c'", expr[0]);
1071 return nullptr;
1072 }
1073 auto arg = Expr(expr);
1074 auto pk = ParsePubkey(key_exp_index, arg, ctx, out, error);
1075 if (!pk) return nullptr;
1076 script_size += pk->GetSize() + 1;
1077 providers.emplace_back(std::move(pk));
1078 key_exp_index++;
1079 }
1080 if (providers.empty() || providers.size() > MAX_PUBKEYS_PER_MULTISIG) {
1081 error = strprintf("Cannot have %u keys in multisig; must have between 1 and %d keys, inclusive", providers.size(), MAX_PUBKEYS_PER_MULTISIG);
1082 return nullptr;
1083 } else if (thres < 1) {
1084 error = strprintf("Multisig threshold cannot be %d, must be at least 1", thres);
1085 return nullptr;
1086 } else if (thres > providers.size()) {
1087 error = strprintf("Multisig threshold cannot be larger than the number of keys; threshold is %d but only %u keys specified", thres, providers.size());
1088 return nullptr;
1089 }
1090 if (ctx == ParseScriptContext::TOP) {
1091 if (providers.size() > 3) {
1092 error = strprintf("Cannot have %u pubkeys in bare multisig; only at most 3 pubkeys", providers.size());
1093 return nullptr;
1094 }
1095 }
1096 if (ctx == ParseScriptContext::P2SH) {
1097 // This limits the maximum number of compressed pubkeys to 15.
1098 if (script_size + 3 > MAX_SCRIPT_ELEMENT_SIZE) {
1099 error = strprintf("P2SH script is too large, %d bytes is larger than %d bytes", script_size + 3, MAX_SCRIPT_ELEMENT_SIZE);
1100 return nullptr;
1101 }
1102 }
1103 return std::make_unique<MultisigDescriptor>(thres, std::move(providers), sorted_multi);
1104 } else if (Func("sortedmulti", expr) || Func("multi", expr)) {
1105 error = "Can only have multi/sortedmulti at top level, in sh(), or in wsh()";
1106 return nullptr;
1107 }
1108 if ((ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH) && Func("wpkh", expr)) {
1109 auto pubkey = ParsePubkey(key_exp_index, expr, ParseScriptContext::P2WPKH, out, error);
1110 if (!pubkey) return nullptr;
1111 key_exp_index++;
1112 return std::make_unique<WPKHDescriptor>(std::move(pubkey));
1113 } else if (Func("wpkh", expr)) {
1114 error = "Can only have wpkh() at top level or inside sh()";
1115 return nullptr;
1116 }
1117 if (ctx == ParseScriptContext::TOP && Func("sh", expr)) {
1118 auto desc = ParseScript(key_exp_index, expr, ParseScriptContext::P2SH, out, error);
1119 if (!desc || expr.size()) return nullptr;
1120 return std::make_unique<SHDescriptor>(std::move(desc));
1121 } else if (Func("sh", expr)) {
1122 error = "Can only have sh() at top level";
1123 return nullptr;
1124 }
1125 if ((ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH) && Func("wsh", expr)) {
1126 auto desc = ParseScript(key_exp_index, expr, ParseScriptContext::P2WSH, out, error);
1127 if (!desc || expr.size()) return nullptr;
1128 return std::make_unique<WSHDescriptor>(std::move(desc));
1129 } else if (Func("wsh", expr)) {
1130 error = "Can only have wsh() at top level or inside sh()";
1131 return nullptr;
1132 }
1133 if (ctx == ParseScriptContext::TOP && Func("addr", expr)) {
1134 CTxDestination dest = DecodeDestination(std::string(expr.begin(), expr.end()));
1135 if (!IsValidDestination(dest)) {
1136 error = "Address is not valid";
1137 return nullptr;
1138 }
1139 return std::make_unique<AddressDescriptor>(std::move(dest));
1140 } else if (Func("addr", expr)) {
1141 error = "Can only have addr() at top level";
1142 return nullptr;
1143 }
1144 if (ctx == ParseScriptContext::TOP && Func("tr", expr)) {
1145 auto arg = Expr(expr);
1146 auto internal_key = ParsePubkey(key_exp_index, arg, ParseScriptContext::P2TR, out, error);
1147 if (!internal_key) return nullptr;
1148 ++key_exp_index;
1149 std::vector<std::unique_ptr<DescriptorImpl>> subscripts; //!< list of script subexpressions
1150 std::vector<int> depths; //!< depth in the tree of each subexpression (same length subscripts)
1151 if (expr.size()) {
1152 if (!Const(",", expr)) {
1153 error = strprintf("tr: expected ',', got '%c'", expr[0]);
1154 return nullptr;
1155 }
1156 /** The path from the top of the tree to what we're currently processing.
1157 * branches[i] == false: left branch in the i'th step from the top; true: right branch.
1158 */
1159 std::vector<bool> branches;
1160 // Loop over all provided scripts. In every iteration exactly one script will be processed.
1161 // Use a do-loop because inside this if-branch we expect at least one script.
1162 do {
1163 // First process all open braces.
1164 while (Const("{", expr)) {
1165 branches.push_back(false); // new left branch
1166 if (branches.size() > TAPROOT_CONTROL_MAX_NODE_COUNT) {
1167 error = strprintf("tr() supports at most %i nesting levels", TAPROOT_CONTROL_MAX_NODE_COUNT);
1168 return nullptr;
1169 }
1170 }
1171 // Process the actual script expression.
1172 auto sarg = Expr(expr);
1173 subscripts.emplace_back(ParseScript(key_exp_index, sarg, ParseScriptContext::P2TR, out, error));
1174 if (!subscripts.back()) return nullptr;
1175 depths.push_back(branches.size());
1176 // Process closing braces; one is expected for every right branch we were in.
1177 while (branches.size() && branches.back()) {
1178 if (!Const("}", expr)) {
1179 error = strprintf("tr(): expected '}' after script expression");
1180 return nullptr;
1181 }
1182 branches.pop_back(); // move up one level after encountering '}'
1183 }
1184 // If after that, we're at the end of a left branch, expect a comma.
1185 if (branches.size() && !branches.back()) {
1186 if (!Const(",", expr)) {
1187 error = strprintf("tr(): expected ',' after script expression");
1188 return nullptr;
1189 }
1190 branches.back() = true; // And now we're in a right branch.
1191 }
1192 } while (branches.size());
1193 // After we've explored a whole tree, we must be at the end of the expression.
1194 if (expr.size()) {
1195 error = strprintf("tr(): expected ')' after script expression");
1196 return nullptr;
1197 }
1198 }
1199 assert(TaprootBuilder::ValidDepths(depths));
1200 return std::make_unique<TRDescriptor>(std::move(internal_key), std::move(subscripts), std::move(depths));
1201 } else if (Func("tr", expr)) {
1202 error = "Can only have tr at top level";
1203 return nullptr;
1204 }
1205 if (ctx == ParseScriptContext::TOP && Func("raw", expr)) {
1206 std::string str(expr.begin(), expr.end());
1207 if (!IsHex(str)) {
1208 error = "Raw script is not hex";
1209 return nullptr;
1210 }
1211 auto bytes = ParseHex(str);
1212 return std::make_unique<RawDescriptor>(CScript(bytes.begin(), bytes.end()));
1213 } else if (Func("raw", expr)) {
1214 error = "Can only have raw() at top level";
1215 return nullptr;
1216 }
1217 if (ctx == ParseScriptContext::P2SH) {
1218 error = "A function is needed within P2SH";
1219 return nullptr;
1220 } else if (ctx == ParseScriptContext::P2WSH) {
1221 error = "A function is needed within P2WSH";
1222 return nullptr;
1223 }
1224 error = strprintf("%s is not a valid descriptor function", std::string(expr.begin(), expr.end()));
1225 return nullptr;
1226 }
1227
InferPubkey(const CPubKey & pubkey,ParseScriptContext,const SigningProvider & provider)1228 std::unique_ptr<PubkeyProvider> InferPubkey(const CPubKey& pubkey, ParseScriptContext, const SigningProvider& provider)
1229 {
1230 std::unique_ptr<PubkeyProvider> key_provider = std::make_unique<ConstPubkeyProvider>(0, pubkey, false);
1231 KeyOriginInfo info;
1232 if (provider.GetKeyOrigin(pubkey.GetID(), info)) {
1233 return std::make_unique<OriginPubkeyProvider>(0, std::move(info), std::move(key_provider));
1234 }
1235 return key_provider;
1236 }
1237
InferXOnlyPubkey(const XOnlyPubKey & xkey,ParseScriptContext ctx,const SigningProvider & provider)1238 std::unique_ptr<PubkeyProvider> InferXOnlyPubkey(const XOnlyPubKey& xkey, ParseScriptContext ctx, const SigningProvider& provider)
1239 {
1240 unsigned char full_key[CPubKey::COMPRESSED_SIZE] = {0x02};
1241 std::copy(xkey.begin(), xkey.end(), full_key + 1);
1242 CPubKey pubkey(full_key);
1243 std::unique_ptr<PubkeyProvider> key_provider = std::make_unique<ConstPubkeyProvider>(0, pubkey, true);
1244 KeyOriginInfo info;
1245 if (provider.GetKeyOrigin(pubkey.GetID(), info)) {
1246 return std::make_unique<OriginPubkeyProvider>(0, std::move(info), std::move(key_provider));
1247 } else {
1248 full_key[0] = 0x03;
1249 pubkey = CPubKey(full_key);
1250 if (provider.GetKeyOrigin(pubkey.GetID(), info)) {
1251 return std::make_unique<OriginPubkeyProvider>(0, std::move(info), std::move(key_provider));
1252 }
1253 }
1254 return key_provider;
1255 }
1256
InferScript(const CScript & script,ParseScriptContext ctx,const SigningProvider & provider)1257 std::unique_ptr<DescriptorImpl> InferScript(const CScript& script, ParseScriptContext ctx, const SigningProvider& provider)
1258 {
1259 if (ctx == ParseScriptContext::P2TR && script.size() == 34 && script[0] == 32 && script[33] == OP_CHECKSIG) {
1260 XOnlyPubKey key{Span<const unsigned char>{script.data() + 1, script.data() + 33}};
1261 return std::make_unique<PKDescriptor>(InferXOnlyPubkey(key, ctx, provider));
1262 }
1263
1264 std::vector<std::vector<unsigned char>> data;
1265 TxoutType txntype = Solver(script, data);
1266
1267 if (txntype == TxoutType::PUBKEY && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH)) {
1268 CPubKey pubkey(data[0]);
1269 if (pubkey.IsValid()) {
1270 return std::make_unique<PKDescriptor>(InferPubkey(pubkey, ctx, provider));
1271 }
1272 }
1273 if (txntype == TxoutType::PUBKEYHASH && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH)) {
1274 uint160 hash(data[0]);
1275 CKeyID keyid(hash);
1276 CPubKey pubkey;
1277 if (provider.GetPubKey(keyid, pubkey)) {
1278 return std::make_unique<PKHDescriptor>(InferPubkey(pubkey, ctx, provider));
1279 }
1280 }
1281 if (txntype == TxoutType::WITNESS_V0_KEYHASH && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH)) {
1282 uint160 hash(data[0]);
1283 CKeyID keyid(hash);
1284 CPubKey pubkey;
1285 if (provider.GetPubKey(keyid, pubkey)) {
1286 return std::make_unique<WPKHDescriptor>(InferPubkey(pubkey, ctx, provider));
1287 }
1288 }
1289 if (txntype == TxoutType::MULTISIG && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH || ctx == ParseScriptContext::P2WSH)) {
1290 std::vector<std::unique_ptr<PubkeyProvider>> providers;
1291 for (size_t i = 1; i + 1 < data.size(); ++i) {
1292 CPubKey pubkey(data[i]);
1293 providers.push_back(InferPubkey(pubkey, ctx, provider));
1294 }
1295 return std::make_unique<MultisigDescriptor>((int)data[0][0], std::move(providers));
1296 }
1297 if (txntype == TxoutType::SCRIPTHASH && ctx == ParseScriptContext::TOP) {
1298 uint160 hash(data[0]);
1299 CScriptID scriptid(hash);
1300 CScript subscript;
1301 if (provider.GetCScript(scriptid, subscript)) {
1302 auto sub = InferScript(subscript, ParseScriptContext::P2SH, provider);
1303 if (sub) return std::make_unique<SHDescriptor>(std::move(sub));
1304 }
1305 }
1306 if (txntype == TxoutType::WITNESS_V0_SCRIPTHASH && (ctx == ParseScriptContext::TOP || ctx == ParseScriptContext::P2SH)) {
1307 CScriptID scriptid;
1308 CRIPEMD160().Write(data[0].data(), data[0].size()).Finalize(scriptid.begin());
1309 CScript subscript;
1310 if (provider.GetCScript(scriptid, subscript)) {
1311 auto sub = InferScript(subscript, ParseScriptContext::P2WSH, provider);
1312 if (sub) return std::make_unique<WSHDescriptor>(std::move(sub));
1313 }
1314 }
1315 if (txntype == TxoutType::WITNESS_V1_TAPROOT && ctx == ParseScriptContext::TOP) {
1316 // Extract x-only pubkey from output.
1317 XOnlyPubKey pubkey;
1318 std::copy(data[0].begin(), data[0].end(), pubkey.begin());
1319 // Request spending data.
1320 TaprootSpendData tap;
1321 if (provider.GetTaprootSpendData(pubkey, tap)) {
1322 // If found, convert it back to tree form.
1323 auto tree = InferTaprootTree(tap, pubkey);
1324 if (tree) {
1325 // If that works, try to infer subdescriptors for all leaves.
1326 bool ok = true;
1327 std::vector<std::unique_ptr<DescriptorImpl>> subscripts; //!< list of script subexpressions
1328 std::vector<int> depths; //!< depth in the tree of each subexpression (same length subscripts)
1329 for (const auto& [depth, script, leaf_ver] : *tree) {
1330 std::unique_ptr<DescriptorImpl> subdesc;
1331 if (leaf_ver == TAPROOT_LEAF_TAPSCRIPT) {
1332 subdesc = InferScript(script, ParseScriptContext::P2TR, provider);
1333 }
1334 if (!subdesc) {
1335 ok = false;
1336 break;
1337 } else {
1338 subscripts.push_back(std::move(subdesc));
1339 depths.push_back(depth);
1340 }
1341 }
1342 if (ok) {
1343 auto key = InferXOnlyPubkey(tap.internal_key, ParseScriptContext::P2TR, provider);
1344 return std::make_unique<TRDescriptor>(std::move(key), std::move(subscripts), std::move(depths));
1345 }
1346 }
1347 }
1348 }
1349
1350 CTxDestination dest;
1351 if (ExtractDestination(script, dest)) {
1352 if (GetScriptForDestination(dest) == script) {
1353 return std::make_unique<AddressDescriptor>(std::move(dest));
1354 }
1355 }
1356
1357 return std::make_unique<RawDescriptor>(script);
1358 }
1359
1360
1361 } // namespace
1362
1363 /** Check a descriptor checksum, and update desc to be the checksum-less part. */
CheckChecksum(Span<const char> & sp,bool require_checksum,std::string & error,std::string * out_checksum=nullptr)1364 bool CheckChecksum(Span<const char>& sp, bool require_checksum, std::string& error, std::string* out_checksum = nullptr)
1365 {
1366 using namespace spanparsing;
1367
1368 auto check_split = Split(sp, '#');
1369 if (check_split.size() > 2) {
1370 error = "Multiple '#' symbols";
1371 return false;
1372 }
1373 if (check_split.size() == 1 && require_checksum){
1374 error = "Missing checksum";
1375 return false;
1376 }
1377 if (check_split.size() == 2) {
1378 if (check_split[1].size() != 8) {
1379 error = strprintf("Expected 8 character checksum, not %u characters", check_split[1].size());
1380 return false;
1381 }
1382 }
1383 auto checksum = DescriptorChecksum(check_split[0]);
1384 if (checksum.empty()) {
1385 error = "Invalid characters in payload";
1386 return false;
1387 }
1388 if (check_split.size() == 2) {
1389 if (!std::equal(checksum.begin(), checksum.end(), check_split[1].begin())) {
1390 error = strprintf("Provided checksum '%s' does not match computed checksum '%s'", std::string(check_split[1].begin(), check_split[1].end()), checksum);
1391 return false;
1392 }
1393 }
1394 if (out_checksum) *out_checksum = std::move(checksum);
1395 sp = check_split[0];
1396 return true;
1397 }
1398
Parse(const std::string & descriptor,FlatSigningProvider & out,std::string & error,bool require_checksum)1399 std::unique_ptr<Descriptor> Parse(const std::string& descriptor, FlatSigningProvider& out, std::string& error, bool require_checksum)
1400 {
1401 Span<const char> sp{descriptor};
1402 if (!CheckChecksum(sp, require_checksum, error)) return nullptr;
1403 uint32_t key_exp_index = 0;
1404 auto ret = ParseScript(key_exp_index, sp, ParseScriptContext::TOP, out, error);
1405 if (sp.size() == 0 && ret) return std::unique_ptr<Descriptor>(std::move(ret));
1406 return nullptr;
1407 }
1408
GetDescriptorChecksum(const std::string & descriptor)1409 std::string GetDescriptorChecksum(const std::string& descriptor)
1410 {
1411 std::string ret;
1412 std::string error;
1413 Span<const char> sp{descriptor};
1414 if (!CheckChecksum(sp, false, error, &ret)) return "";
1415 return ret;
1416 }
1417
InferDescriptor(const CScript & script,const SigningProvider & provider)1418 std::unique_ptr<Descriptor> InferDescriptor(const CScript& script, const SigningProvider& provider)
1419 {
1420 return InferScript(script, ParseScriptContext::TOP, provider);
1421 }
1422
CacheParentExtPubKey(uint32_t key_exp_pos,const CExtPubKey & xpub)1423 void DescriptorCache::CacheParentExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub)
1424 {
1425 m_parent_xpubs[key_exp_pos] = xpub;
1426 }
1427
CacheDerivedExtPubKey(uint32_t key_exp_pos,uint32_t der_index,const CExtPubKey & xpub)1428 void DescriptorCache::CacheDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, const CExtPubKey& xpub)
1429 {
1430 auto& xpubs = m_derived_xpubs[key_exp_pos];
1431 xpubs[der_index] = xpub;
1432 }
1433
CacheLastHardenedExtPubKey(uint32_t key_exp_pos,const CExtPubKey & xpub)1434 void DescriptorCache::CacheLastHardenedExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub)
1435 {
1436 m_last_hardened_xpubs[key_exp_pos] = xpub;
1437 }
1438
GetCachedParentExtPubKey(uint32_t key_exp_pos,CExtPubKey & xpub) const1439 bool DescriptorCache::GetCachedParentExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const
1440 {
1441 const auto& it = m_parent_xpubs.find(key_exp_pos);
1442 if (it == m_parent_xpubs.end()) return false;
1443 xpub = it->second;
1444 return true;
1445 }
1446
GetCachedDerivedExtPubKey(uint32_t key_exp_pos,uint32_t der_index,CExtPubKey & xpub) const1447 bool DescriptorCache::GetCachedDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, CExtPubKey& xpub) const
1448 {
1449 const auto& key_exp_it = m_derived_xpubs.find(key_exp_pos);
1450 if (key_exp_it == m_derived_xpubs.end()) return false;
1451 const auto& der_it = key_exp_it->second.find(der_index);
1452 if (der_it == key_exp_it->second.end()) return false;
1453 xpub = der_it->second;
1454 return true;
1455 }
1456
GetCachedLastHardenedExtPubKey(uint32_t key_exp_pos,CExtPubKey & xpub) const1457 bool DescriptorCache::GetCachedLastHardenedExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const
1458 {
1459 const auto& it = m_last_hardened_xpubs.find(key_exp_pos);
1460 if (it == m_last_hardened_xpubs.end()) return false;
1461 xpub = it->second;
1462 return true;
1463 }
1464
MergeAndDiff(const DescriptorCache & other)1465 DescriptorCache DescriptorCache::MergeAndDiff(const DescriptorCache& other)
1466 {
1467 DescriptorCache diff;
1468 for (const auto& parent_xpub_pair : other.GetCachedParentExtPubKeys()) {
1469 CExtPubKey xpub;
1470 if (GetCachedParentExtPubKey(parent_xpub_pair.first, xpub)) {
1471 if (xpub != parent_xpub_pair.second) {
1472 throw std::runtime_error(std::string(__func__) + ": New cached parent xpub does not match already cached parent xpub");
1473 }
1474 continue;
1475 }
1476 CacheParentExtPubKey(parent_xpub_pair.first, parent_xpub_pair.second);
1477 diff.CacheParentExtPubKey(parent_xpub_pair.first, parent_xpub_pair.second);
1478 }
1479 for (const auto& derived_xpub_map_pair : other.GetCachedDerivedExtPubKeys()) {
1480 for (const auto& derived_xpub_pair : derived_xpub_map_pair.second) {
1481 CExtPubKey xpub;
1482 if (GetCachedDerivedExtPubKey(derived_xpub_map_pair.first, derived_xpub_pair.first, xpub)) {
1483 if (xpub != derived_xpub_pair.second) {
1484 throw std::runtime_error(std::string(__func__) + ": New cached derived xpub does not match already cached derived xpub");
1485 }
1486 continue;
1487 }
1488 CacheDerivedExtPubKey(derived_xpub_map_pair.first, derived_xpub_pair.first, derived_xpub_pair.second);
1489 diff.CacheDerivedExtPubKey(derived_xpub_map_pair.first, derived_xpub_pair.first, derived_xpub_pair.second);
1490 }
1491 }
1492 for (const auto& lh_xpub_pair : other.GetCachedLastHardenedExtPubKeys()) {
1493 CExtPubKey xpub;
1494 if (GetCachedLastHardenedExtPubKey(lh_xpub_pair.first, xpub)) {
1495 if (xpub != lh_xpub_pair.second) {
1496 throw std::runtime_error(std::string(__func__) + ": New cached last hardened xpub does not match already cached last hardened xpub");
1497 }
1498 continue;
1499 }
1500 CacheLastHardenedExtPubKey(lh_xpub_pair.first, lh_xpub_pair.second);
1501 diff.CacheLastHardenedExtPubKey(lh_xpub_pair.first, lh_xpub_pair.second);
1502 }
1503 return diff;
1504 }
1505
GetCachedParentExtPubKeys() const1506 const ExtPubKeyMap DescriptorCache::GetCachedParentExtPubKeys() const
1507 {
1508 return m_parent_xpubs;
1509 }
1510
GetCachedDerivedExtPubKeys() const1511 const std::unordered_map<uint32_t, ExtPubKeyMap> DescriptorCache::GetCachedDerivedExtPubKeys() const
1512 {
1513 return m_derived_xpubs;
1514 }
1515
GetCachedLastHardenedExtPubKeys() const1516 const ExtPubKeyMap DescriptorCache::GetCachedLastHardenedExtPubKeys() const
1517 {
1518 return m_last_hardened_xpubs;
1519 }
1520