diff options
Diffstat (limited to 'src/script/script.h')
| -rw-r--r-- | src/script/script.h | 35 |
1 files changed, 27 insertions, 8 deletions
diff --git a/src/script/script.h b/src/script/script.h index d450db5cad..05f2e7e3a9 100644 --- a/src/script/script.h +++ b/src/script/script.h @@ -192,10 +192,29 @@ public: m_value = n; } - explicit CScriptNum(const std::vector<unsigned char>& vch) + explicit CScriptNum(const std::vector<unsigned char>& vch, bool fRequireMinimal) { - if (vch.size() > nMaxNumSize) - throw scriptnum_error("CScriptNum(const std::vector<unsigned char>&) : overflow"); + if (vch.size() > nMaxNumSize) { + throw scriptnum_error("script number overflow"); + } + if (fRequireMinimal && vch.size() > 0) { + // Check that the number is encoded with the minimum possible + // number of bytes. + // + // If the most-significant-byte - excluding the sign bit - is zero + // then we're not minimal. Note how this test also rejects the + // negative-zero encoding, 0x80. + if ((vch.back() & 0x7f) == 0) { + // One exception: if there's more than one byte and the most + // significant bit of the second-most-significant-byte is set + // it would conflict with the sign bit. An example of this case + // is +-255, which encode to 0xff00 and 0xff80 respectively. + // (big-endian). + if (vch.size() <= 1 || (vch[vch.size() - 2] & 0x80) == 0) { + throw scriptnum_error("non-minimally encoded script number"); + } + } + } m_value = set_vch(vch); } @@ -319,7 +338,6 @@ private: int64_t m_value; }; - /** Serialized script, used inside transaction inputs and outputs */ class CScript : public std::vector<unsigned char> { @@ -330,6 +348,10 @@ protected: { push_back(n + (OP_1 - 1)); } + else if (n == 0) + { + push_back(OP_0); + } else { *this << CScriptNum::serialize(n); @@ -551,12 +573,9 @@ public: bool IsPayToScriptHash() const; - // Called by IsStandardTx and P2SH VerifyScript (which makes it consensus-critical). + // Called by IsStandardTx and P2SH/BIP62 VerifyScript (which makes it consensus-critical). bool IsPushOnly() const; - // Called by IsStandardTx. - bool HasCanonicalPushes() const; - // Returns whether the script is guaranteed to fail at execution, // regardless of the initial stack. This allows outputs to be pruned // instantly when entering the UTXO set. |