// Copyright (c) 2019-2022 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 <string>
#include <vector>
#include <script/script.h>
#include <script/miniscript.h>
#include <assert.h>
namespace miniscript {
namespace internal {
Type SanitizeType(Type e) {
int num_types = (e << "K"_mst) + (e << "V"_mst) + (e << "B"_mst) + (e << "W"_mst);
if (num_types == 0) return ""_mst; // No valid type, don't care about the rest
assert(num_types == 1); // K, V, B, W all conflict with each other
assert(!(e << "z"_mst) || !(e << "o"_mst)); // z conflicts with o
assert(!(e << "n"_mst) || !(e << "z"_mst)); // n conflicts with z
assert(!(e << "n"_mst) || !(e << "W"_mst)); // n conflicts with W
assert(!(e << "V"_mst) || !(e << "d"_mst)); // V conflicts with d
assert(!(e << "K"_mst) || (e << "u"_mst)); // K implies u
assert(!(e << "V"_mst) || !(e << "u"_mst)); // V conflicts with u
assert(!(e << "e"_mst) || !(e << "f"_mst)); // e conflicts with f
assert(!(e << "e"_mst) || (e << "d"_mst)); // e implies d
assert(!(e << "V"_mst) || !(e << "e"_mst)); // V conflicts with e
assert(!(e << "d"_mst) || !(e << "f"_mst)); // d conflicts with f
assert(!(e << "V"_mst) || (e << "f"_mst)); // V implies f
assert(!(e << "K"_mst) || (e << "s"_mst)); // K implies s
assert(!(e << "z"_mst) || (e << "m"_mst)); // z implies m
return e;
}
Type ComputeType(Fragment fragment, Type x, Type y, Type z, const std::vector<Type>& sub_types, uint32_t k,
size_t data_size, size_t n_subs, size_t n_keys, MiniscriptContext ms_ctx) {
// Sanity check on data
if (fragment == Fragment::SHA256 || fragment == Fragment::HASH256) {
assert(data_size == 32);
} else if (fragment == Fragment::RIPEMD160 || fragment == Fragment::HASH160) {
assert(data_size == 20);
} else {
assert(data_size == 0);
}
// Sanity check on k
if (fragment == Fragment::OLDER || fragment == Fragment::AFTER) {
assert(k >= 1 && k < 0x80000000UL);
} else if (fragment == Fragment::MULTI || fragment == Fragment::MULTI_A) {
assert(k >= 1 && k <= n_keys);
} else if (fragment == Fragment::THRESH) {
assert(k >= 1 && k <= n_subs);
} else {
assert(k == 0);
}
// Sanity check on subs
if (fragment == Fragment::AND_V || fragment == Fragment::AND_B || fragment == Fragment::OR_B ||
fragment == Fragment::OR_C || fragment == Fragment::OR_I || fragment == Fragment::OR_D) {
assert(n_subs == 2);
} else if (fragment == Fragment::ANDOR) {
assert(n_subs == 3);
} else if (fragment == Fragment::WRAP_A || fragment == Fragment::WRAP_S || fragment == Fragment::WRAP_C ||
fragment == Fragment::WRAP_D || fragment == Fragment::WRAP_V || fragment == Fragment::WRAP_J ||
fragment == Fragment::WRAP_N) {
assert(n_subs == 1);
} else if (fragment != Fragment::THRESH) {
assert(n_subs == 0);
}
// Sanity check on keys
if (fragment == Fragment::PK_K || fragment == Fragment::PK_H) {
assert(n_keys == 1);
} else if (fragment == Fragment::MULTI) {
assert(n_keys >= 1 && n_keys <= MAX_PUBKEYS_PER_MULTISIG);
assert(!IsTapscript(ms_ctx));
} else if (fragment == Fragment::MULTI_A) {
assert(n_keys >= 1 && n_keys <= MAX_PUBKEYS_PER_MULTI_A);
assert(IsTapscript(ms_ctx));
} else {
assert(n_keys == 0);
}
// Below is the per-fragment logic for computing the expression types.
// It heavily relies on Type's << operator (where "X << a_mst" means
// "X has all properties listed in a").
switch (fragment) {
case Fragment::PK_K: return "Konudemsxk"_mst;
case Fragment::PK_H: return "Knudemsxk"_mst;
case Fragment::OLDER: return
"g"_mst.If(k & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) |
"h"_mst.If(!(k & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG)) |
"Bzfmxk"_mst;
case Fragment::AFTER: return
"i"_mst.If(k >= LOCKTIME_THRESHOLD) |
"j"_mst.If(k < LOCKTIME_THRESHOLD) |
"Bzfmxk"_mst;
case Fragment::SHA256: return "Bonudmk"_mst;
case Fragment::RIPEMD160: return "Bonudmk"_mst;
case Fragment::HASH256: return "Bonudmk"_mst;
case Fragment::HASH160: return "Bonudmk"_mst;
case Fragment::JUST_1: return "Bzufmxk"_mst;
case Fragment::JUST_0: return "Bzudemsxk"_mst;
case Fragment::WRAP_A: return
"W"_mst.If(x << "B"_mst) | // W=B_x
(x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
(x & "udfems"_mst) | // u=u_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x
"x"_mst; // x
case Fragment::WRAP_S: return
"W"_mst.If(x << "Bo"_mst) | // W=B_x*o_x
(x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
(x & "udfemsx"_mst); // u=u_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x, x=x_x
case Fragment::WRAP_C: return
"B"_mst.If(x << "K"_mst) | // B=K_x
(x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
(x & "ondfem"_mst) | // o=o_x, n=n_x, d=d_x, f=f_x, e=e_x, m=m_x
"us"_mst; // u, s
case Fragment::WRAP_D: return
"B"_mst.If(x << "Vz"_mst) | // B=V_x*z_x
"o"_mst.If(x << "z"_mst) | // o=z_x
"e"_mst.If(x << "f"_mst) | // e=f_x
(x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
(x & "ms"_mst) | // m=m_x, s=s_x
// NOTE: 'd:' is 'u' under Tapscript but not P2WSH as MINIMALIF is only a policy rule there.
"u"_mst.If(IsTapscript(ms_ctx)) |
"ndx"_mst; // n, d, x
case Fragment::WRAP_V: return
"V"_mst.If(x << "B"_mst) | // V=B_x
(x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
(x & "zonms"_mst) | // z=z_x, o=o_x, n=n_x, m=m_x, s=s_x
"fx"_mst; // f, x
case Fragment::WRAP_J: return
"B"_mst.If(x << "Bn"_mst) | // B=B_x*n_x
"e"_mst.If(x << "f"_mst) | // e=f_x
(x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
(x & "oums"_mst) | // o=o_x, u=u_x, m=m_x, s=s_x
"ndx"_mst; // n, d, x
case Fragment::WRAP_N: return
(x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
(x & "Bzondfems"_mst) | // B=B_x, z=z_x, o=o_x, n=n_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x
"ux"_mst; // u, x
case Fragment::AND_V: return
(y & "KVB"_mst).If(x << "V"_mst) | // B=V_x*B_y, V=V_x*V_y, K=V_x*K_y
(x & "n"_mst) | (y & "n"_mst).If(x << "z"_mst) | // n=n_x+z_x*n_y
((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
(x & y & "dmz"_mst) | // d=d_x*d_y, m=m_x*m_y, z=z_x*z_y
((x | y) & "s"_mst) | // s=s_x+s_y
"f"_mst.If((y << "f"_mst) || (x << "s"_mst)) | // f=f_y+s_x
(y & "ux"_mst) | // u=u_y, x=x_y
((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
"k"_mst.If(((x & y) << "k"_mst) &&
!(((x << "g"_mst) && (y << "h"_mst)) ||
((x << "h"_mst) && (y << "g"_mst)) ||
((x << "i"_mst) && (y << "j"_mst)) ||
((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*!(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
case Fragment::AND_B: return
(x & "B"_mst).If(y << "W"_mst) | // B=B_x*W_y
((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
(x & "n"_mst) | (y & "n"_mst).If(x << "z"_mst) | // n=n_x+z_x*n_y
(x & y & "e"_mst).If((x & y) << "s"_mst) | // e=e_x*e_y*s_x*s_y
(x & y & "dzm"_mst) | // d=d_x*d_y, z=z_x*z_y, m=m_x*m_y
"f"_mst.If(((x & y) << "f"_mst) || (x << "sf"_mst) || (y << "sf"_mst)) | // f=f_x*f_y + f_x*s_x + f_y*s_y
((x | y) & "s"_mst) | // s=s_x+s_y
"ux"_mst | // u, x
((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
"k"_mst.If(((x & y) << "k"_mst) &&
!(((x << "g"_mst) && (y << "h"_mst)) ||
((x << "h"_mst) && (y << "g"_mst)) ||
((x << "i"_mst) && (y << "j"_mst)) ||
((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*!(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
case Fragment::OR_B: return
"B"_mst.If(x << "Bd"_mst && y << "Wd"_mst) | // B=B_x*d_x*W_x*d_y
((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
(x & y & "m"_mst).If((x | y) << "s"_mst && (x & y) << "e"_mst) | // m=m_x*m_y*e_x*e_y*(s_x+s_y)
(x & y & "zse"_mst) | // z=z_x*z_y, s=s_x*s_y, e=e_x*e_y
"dux"_mst | // d, u, x
((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
(x & y & "k"_mst); // k=k_x*k_y
case Fragment::OR_D: return
(y & "B"_mst).If(x << "Bdu"_mst) | // B=B_y*B_x*d_x*u_x
(x & "o"_mst).If(y << "z"_mst) | // o=o_x*z_y
(x & y & "m"_mst).If(x << "e"_mst && (x | y) << "s"_mst) | // m=m_x*m_y*e_x*(s_x+s_y)
(x & y & "zs"_mst) | // z=z_x*z_y, s=s_x*s_y
(y & "ufde"_mst) | // u=u_y, f=f_y, d=d_y, e=e_y
"x"_mst | // x
((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
(x & y & "k"_mst); // k=k_x*k_y
case Fragment::OR_C: return
(y & "V"_mst).If(x << "Bdu"_mst) | // V=V_y*B_x*u_x*d_x
(x & "o"_mst).If(y << "z"_mst) | // o=o_x*z_y
(x & y & "m"_mst).If(x << "e"_mst && (x | y) << "s"_mst) | // m=m_x*m_y*e_x*(s_x+s_y)
(x & y & "zs"_mst) | // z=z_x*z_y, s=s_x*s_y
"fx"_mst | // f, x
((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
(x & y & "k"_mst); // k=k_x*k_y
case Fragment::OR_I: return
(x & y & "VBKufs"_mst) | // V=V_x*V_y, B=B_x*B_y, K=K_x*K_y, u=u_x*u_y, f=f_x*f_y, s=s_x*s_y
"o"_mst.If((x & y) << "z"_mst) | // o=z_x*z_y
((x | y) & "e"_mst).If((x | y) << "f"_mst) | // e=e_x*f_y+f_x*e_y
(x & y & "m"_mst).If((x | y) << "s"_mst) | // m=m_x*m_y*(s_x+s_y)
((x | y) & "d"_mst) | // d=d_x+d_y
"x"_mst | // x
((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
(x & y & "k"_mst); // k=k_x*k_y
case Fragment::ANDOR: return
(y & z & "BKV"_mst).If(x << "Bdu"_mst) | // B=B_x*d_x*u_x*B_y*B_z, K=B_x*d_x*u_x*K_y*K_z, V=B_x*d_x*u_x*V_y*V_z
(x & y & z & "z"_mst) | // z=z_x*z_y*z_z
((x | (y & z)) & "o"_mst).If((x | (y & z)) << "z"_mst) | // o=o_x*z_y*z_z+z_x*o_y*o_z
(y & z & "u"_mst) | // u=u_y*u_z
(z & "f"_mst).If((x << "s"_mst) || (y << "f"_mst)) | // f=(s_x+f_y)*f_z
(z & "d"_mst) | // d=d_z
(z & "e"_mst).If(x << "s"_mst || y << "f"_mst) | // e=e_z*(s_x+f_y)
(x & y & z & "m"_mst).If(x << "e"_mst && (x | y | z) << "s"_mst) | // m=m_x*m_y*m_z*e_x*(s_x+s_y+s_z)
(z & (x | y) & "s"_mst) | // s=s_z*(s_x+s_y)
"x"_mst | // x
((x | y | z) & "ghij"_mst) | // g=g_x+g_y+g_z, h=h_x+h_y+h_z, i=i_x+i_y+i_z, j=j_x+j_y_j_z
"k"_mst.If(((x & y & z) << "k"_mst) &&
!(((x << "g"_mst) && (y << "h"_mst)) ||
((x << "h"_mst) && (y << "g"_mst)) ||
((x << "i"_mst) && (y << "j"_mst)) ||
((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*k_z* !(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
case Fragment::MULTI: {
return "Bnudemsk"_mst;
}
case Fragment::MULTI_A: {
return "Budemsk"_mst;
}
case Fragment::THRESH: {
bool all_e = true;
bool all_m = true;
uint32_t args = 0;
uint32_t num_s = 0;
Type acc_tl = "k"_mst;
for (size_t i = 0; i < sub_types.size(); ++i) {
Type t = sub_types[i];
if (!(t << (i ? "Wdu"_mst : "Bdu"_mst))) return ""_mst; // Require Bdu, Wdu, Wdu, ...
if (!(t << "e"_mst)) all_e = false;
if (!(t << "m"_mst)) all_m = false;
if (t << "s"_mst) num_s += 1;
args += (t << "z"_mst) ? 0 : (t << "o"_mst) ? 1 : 2;
acc_tl = ((acc_tl | t) & "ghij"_mst) |
// Thresh contains a combination of timelocks if it has threshold > 1 and
// it contains two different children that have different types of timelocks
// Note how if any of the children don't have "k", the parent also does not have "k"
"k"_mst.If(((acc_tl & t) << "k"_mst) && ((k <= 1) ||
((k > 1) && !(((acc_tl << "g"_mst) && (t << "h"_mst)) ||
((acc_tl << "h"_mst) && (t << "g"_mst)) ||
((acc_tl << "i"_mst) && (t << "j"_mst)) ||
((acc_tl << "j"_mst) && (t << "i"_mst))))));
}
return "Bdu"_mst |
"z"_mst.If(args == 0) | // z=all z
"o"_mst.If(args == 1) | // o=all z except one o
"e"_mst.If(all_e && num_s == n_subs) | // e=all e and all s
"m"_mst.If(all_e && all_m && num_s >= n_subs - k) | // m=all e, >=(n-k) s
"s"_mst.If(num_s >= n_subs - k + 1) | // s= >=(n-k+1) s
acc_tl; // timelock info
}
}
assert(false);
}
size_t ComputeScriptLen(Fragment fragment, Type sub0typ, size_t subsize, uint32_t k, size_t n_subs, size_t n_keys) {
switch (fragment) {
case Fragment::JUST_1:
case Fragment::JUST_0: return 1;
case Fragment::PK_K: return 34;
case Fragment::PK_H: return 3 + 21;
case Fragment::OLDER:
case Fragment::AFTER: return 1 + BuildScript(k).size();
case Fragment::HASH256:
case Fragment::SHA256: return 4 + 2 + 33;
case Fragment::HASH160:
case Fragment::RIPEMD160: return 4 + 2 + 21;
case Fragment::MULTI: return 1 + BuildScript(n_keys).size() + BuildScript(k).size() + 34 * n_keys;
case Fragment::MULTI_A: return (1 + 32 + 1) * n_keys + BuildScript(k).size() + 1;
case Fragment::AND_V: return subsize;
case Fragment::WRAP_V: return subsize + (sub0typ << "x"_mst);
case Fragment::WRAP_S:
case Fragment::WRAP_C:
case Fragment::WRAP_N:
case Fragment::AND_B:
case Fragment::OR_B: return subsize + 1;
case Fragment::WRAP_A:
case Fragment::OR_C: return subsize + 2;
case Fragment::WRAP_D:
case Fragment::OR_D:
case Fragment::OR_I:
case Fragment::ANDOR: return subsize + 3;
case Fragment::WRAP_J: return subsize + 4;
case Fragment::THRESH: return subsize + n_subs + BuildScript(k).size();
}
assert(false);
}
InputStack& InputStack::SetAvailable(Availability avail) {
available = avail;
if (avail == Availability::NO) {
stack.clear();
size = std::numeric_limits<size_t>::max();
has_sig = false;
malleable = false;
non_canon = false;
}
return *this;
}
InputStack& InputStack::SetWithSig() {
has_sig = true;
return *this;
}
InputStack& InputStack::SetNonCanon() {
non_canon = true;
return *this;
}
InputStack& InputStack::SetMalleable(bool x) {
malleable = x;
return *this;
}
InputStack operator+(InputStack a, InputStack b) {
a.stack = Cat(std::move(a.stack), std::move(b.stack));
if (a.available != Availability::NO && b.available != Availability::NO) a.size += b.size;
a.has_sig |= b.has_sig;
a.malleable |= b.malleable;
a.non_canon |= b.non_canon;
if (a.available == Availability::NO || b.available == Availability::NO) {
a.SetAvailable(Availability::NO);
} else if (a.available == Availability::MAYBE || b.available == Availability::MAYBE) {
a.SetAvailable(Availability::MAYBE);
}
return a;
}
InputStack operator|(InputStack a, InputStack b) {
// If only one is invalid, pick the other one. If both are invalid, pick an arbitrary one.
if (a.available == Availability::NO) return b;
if (b.available == Availability::NO) return a;
// If only one of the solutions has a signature, we must pick the other one.
if (!a.has_sig && b.has_sig) return a;
if (!b.has_sig && a.has_sig) return b;
if (!a.has_sig && !b.has_sig) {
// If neither solution requires a signature, the result is inevitably malleable.
a.malleable = true;
b.malleable = true;
} else {
// If both options require a signature, prefer the non-malleable one.
if (b.malleable && !a.malleable) return a;
if (a.malleable && !b.malleable) return b;
}
// Between two malleable or two non-malleable solutions, pick the smaller one between
// YESes, and the bigger ones between MAYBEs. Prefer YES over MAYBE.
if (a.available == Availability::YES && b.available == Availability::YES) {
return std::move(a.size <= b.size ? a : b);
} else if (a.available == Availability::MAYBE && b.available == Availability::MAYBE) {
return std::move(a.size >= b.size ? a : b);
} else if (a.available == Availability::YES) {
return a;
} else {
return b;
}
}
std::optional<std::vector<Opcode>> DecomposeScript(const CScript& script)
{
std::vector<Opcode> out;
CScript::const_iterator it = script.begin(), itend = script.end();
while (it != itend) {
std::vector<unsigned char> push_data;
opcodetype opcode;
if (!script.GetOp(it, opcode, push_data)) {
return {};
} else if (opcode >= OP_1 && opcode <= OP_16) {
// Deal with OP_n (GetOp does not turn them into pushes).
push_data.assign(1, CScript::DecodeOP_N(opcode));
} else if (opcode == OP_CHECKSIGVERIFY) {
// Decompose OP_CHECKSIGVERIFY into OP_CHECKSIG OP_VERIFY
out.emplace_back(OP_CHECKSIG, std::vector<unsigned char>());
opcode = OP_VERIFY;
} else if (opcode == OP_CHECKMULTISIGVERIFY) {
// Decompose OP_CHECKMULTISIGVERIFY into OP_CHECKMULTISIG OP_VERIFY
out.emplace_back(OP_CHECKMULTISIG, std::vector<unsigned char>());
opcode = OP_VERIFY;
} else if (opcode == OP_EQUALVERIFY) {
// Decompose OP_EQUALVERIFY into OP_EQUAL OP_VERIFY
out.emplace_back(OP_EQUAL, std::vector<unsigned char>());
opcode = OP_VERIFY;
} else if (opcode == OP_NUMEQUALVERIFY) {
// Decompose OP_NUMEQUALVERIFY into OP_NUMEQUAL OP_VERIFY
out.emplace_back(OP_NUMEQUAL, std::vector<unsigned char>());
opcode = OP_VERIFY;
} else if (IsPushdataOp(opcode)) {
if (!CheckMinimalPush(push_data, opcode)) return {};
} else if (it != itend && (opcode == OP_CHECKSIG || opcode == OP_CHECKMULTISIG || opcode == OP_EQUAL || opcode == OP_NUMEQUAL) && (*it == OP_VERIFY)) {
// Rule out non minimal VERIFY sequences
return {};
}
out.emplace_back(opcode, std::move(push_data));
}
std::reverse(out.begin(), out.end());
return out;
}
std::optional<int64_t> ParseScriptNumber(const Opcode& in) {
if (in.first == OP_0) {
return 0;
}
if (!in.second.empty()) {
if (IsPushdataOp(in.first) && !CheckMinimalPush(in.second, in.first)) return {};
try {
return CScriptNum(in.second, true).GetInt64();
} catch(const scriptnum_error&) {}
}
return {};
}
int FindNextChar(Span<const char> sp, const char m)
{
for (int i = 0; i < (int)sp.size(); ++i) {
if (sp[i] == m) return i;
// We only search within the current parentheses
if (sp[i] == ')') break;
}
return -1;
}
} // namespace internal
} // namespace miniscript