Line data Source code
1 : // Copyright (c) 2009-2010 Satoshi Nakamoto
2 : // Copyright (c) 2009-2014 The Bitcoin Core developers
3 : // Distributed under the MIT software license, see the accompanying
4 : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 :
6 : #ifndef BITCOIN_SCRIPT_INTERPRETER_H
7 : #define BITCOIN_SCRIPT_INTERPRETER_H
8 :
9 : #include "script_error.h"
10 : #include "primitives/transaction.h"
11 :
12 : #include <vector>
13 : #include <stdint.h>
14 : #include <string>
15 :
16 : class CPubKey;
17 : class CScript;
18 : class CTransaction;
19 : class uint256;
20 :
21 : /** Signature hash types/flags */
22 : enum
23 : {
24 : SIGHASH_ALL = 1,
25 : SIGHASH_NONE = 2,
26 : SIGHASH_SINGLE = 3,
27 : SIGHASH_ANYONECANPAY = 0x80,
28 : };
29 :
30 : /** Script verification flags */
31 : enum
32 : {
33 : SCRIPT_VERIFY_NONE = 0,
34 :
35 : // Evaluate P2SH subscripts (softfork safe, BIP16).
36 : SCRIPT_VERIFY_P2SH = (1U << 0),
37 :
38 : // Passing a non-strict-DER signature or one with undefined hashtype to a checksig operation causes script failure.
39 : // Evaluating a pubkey that is not (0x04 + 64 bytes) or (0x02 or 0x03 + 32 bytes) by checksig causes script failure.
40 : // (softfork safe, but not used or intended as a consensus rule).
41 : SCRIPT_VERIFY_STRICTENC = (1U << 1),
42 :
43 : // Passing a non-strict-DER signature to a checksig operation causes script failure (softfork safe, BIP62 rule 1)
44 : SCRIPT_VERIFY_DERSIG = (1U << 2),
45 :
46 : // Passing a non-strict-DER signature or one with S > order/2 to a checksig operation causes script failure
47 : // (softfork safe, BIP62 rule 5).
48 : SCRIPT_VERIFY_LOW_S = (1U << 3),
49 :
50 : // verify dummy stack item consumed by CHECKMULTISIG is of zero-length (softfork safe, BIP62 rule 7).
51 : SCRIPT_VERIFY_NULLDUMMY = (1U << 4),
52 :
53 : // Using a non-push operator in the scriptSig causes script failure (softfork safe, BIP62 rule 2).
54 : SCRIPT_VERIFY_SIGPUSHONLY = (1U << 5),
55 :
56 : // Require minimal encodings for all push operations (OP_0... OP_16, OP_1NEGATE where possible, direct
57 : // pushes up to 75 bytes, OP_PUSHDATA up to 255 bytes, OP_PUSHDATA2 for anything larger). Evaluating
58 : // any other push causes the script to fail (BIP62 rule 3).
59 : // In addition, whenever a stack element is interpreted as a number, it must be of minimal length (BIP62 rule 4).
60 : // (softfork safe)
61 : SCRIPT_VERIFY_MINIMALDATA = (1U << 6),
62 :
63 : // Discourage use of NOPs reserved for upgrades (NOP1-10)
64 : //
65 : // Provided so that nodes can avoid accepting or mining transactions
66 : // containing executed NOP's whose meaning may change after a soft-fork,
67 : // thus rendering the script invalid; with this flag set executing
68 : // discouraged NOPs fails the script. This verification flag will never be
69 : // a mandatory flag applied to scripts in a block. NOPs that are not
70 : // executed, e.g. within an unexecuted IF ENDIF block, are *not* rejected.
71 : SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS = (1U << 7),
72 :
73 : // Require that only a single stack element remains after evaluation. This changes the success criterion from
74 : // "At least one stack element must remain, and when interpreted as a boolean, it must be true" to
75 : // "Exactly one stack element must remain, and when interpreted as a boolean, it must be true".
76 : // (softfork safe, BIP62 rule 6)
77 : // Note: CLEANSTACK should never be used without P2SH.
78 : SCRIPT_VERIFY_CLEANSTACK = (1U << 8),
79 :
80 : // Verify CHECKLOCKTIMEVERIFY
81 : //
82 : // See BIP65 for details.
83 : SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 9),
84 : };
85 :
86 : bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror);
87 :
88 : uint256 SignatureHash(const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType);
89 :
90 76983 : class BaseSignatureChecker
91 : {
92 : public:
93 0 : virtual bool CheckSig(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode) const
94 : {
95 0 : return false;
96 : }
97 :
98 0 : virtual bool CheckLockTime(const CScriptNum& nLockTime) const
99 : {
100 0 : return false;
101 : }
102 :
103 76983 : virtual ~BaseSignatureChecker() {}
104 : };
105 :
106 18356 : class TransactionSignatureChecker : public BaseSignatureChecker
107 : {
108 : private:
109 : const CTransaction* txTo;
110 : unsigned int nIn;
111 :
112 : protected:
113 : virtual bool VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& vchPubKey, const uint256& sighash) const;
114 :
115 : public:
116 18356 : TransactionSignatureChecker(const CTransaction* txToIn, unsigned int nInIn) : txTo(txToIn), nIn(nInIn) {}
117 : bool CheckSig(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode) const;
118 : bool CheckLockTime(const CScriptNum& nLockTime) const;
119 : };
120 :
121 3687 : class MutableTransactionSignatureChecker : public TransactionSignatureChecker
122 : {
123 : private:
124 : const CTransaction txTo;
125 :
126 : public:
127 2458 : MutableTransactionSignatureChecker(const CMutableTransaction* txToIn, unsigned int nInIn) : TransactionSignatureChecker(&txTo, nInIn), txTo(*txToIn) {}
128 : };
129 :
130 : bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* error = NULL);
131 : bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* error = NULL);
132 :
133 : #endif // BITCOIN_SCRIPT_INTERPRETER_H
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