diff options
author | Johnson Lau <jl2012@xbt.hk> | 2018-04-27 03:56:29 +0800 |
---|---|---|
committer | Johnson Lau <jl2012@xbt.hk> | 2018-05-05 04:26:12 +0800 |
commit | 9dabfe49c066301ef75bcfcb089fd308366127c4 (patch) | |
tree | 9640b1303dc21c3dc68463833d9f34145a118b2e /src | |
parent | 627c3762ce5d8ce097f70c7fb52a3640246fae9b (diff) |
Add constant scriptCode policy in non-segwit scripts
This disables OP_CODESEPARATOR in non-segwit scripts (even in an unexecuted branch), and makes a positive FindAndDelete result invalid. This ensures that the scriptCode serialized in SignatureHash() is always the same as the script passing to the EvalScript.
Diffstat (limited to 'src')
-rw-r--r-- | src/policy/policy.h | 3 | ||||
-rw-r--r-- | src/script/interpreter.cpp | 15 | ||||
-rw-r--r-- | src/script/interpreter.h | 4 | ||||
-rw-r--r-- | src/script/script_error.cpp | 4 | ||||
-rw-r--r-- | src/script/script_error.h | 4 | ||||
-rw-r--r-- | src/test/script_tests.cpp | 2 |
6 files changed, 29 insertions, 3 deletions
diff --git a/src/policy/policy.h b/src/policy/policy.h index e4eda4b635..6ba3ba7450 100644 --- a/src/policy/policy.h +++ b/src/policy/policy.h @@ -63,7 +63,8 @@ static constexpr unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VE SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM | - SCRIPT_VERIFY_WITNESS_PUBKEYTYPE; + SCRIPT_VERIFY_WITNESS_PUBKEYTYPE | + SCRIPT_VERIFY_CONST_SCRIPTCODE; /** For convenience, standard but not mandatory verify flags. */ static constexpr unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS; diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp index e0d193fa38..13f41a7cbf 100644 --- a/src/script/interpreter.cpp +++ b/src/script/interpreter.cpp @@ -336,6 +336,10 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& opcode == OP_RSHIFT) return set_error(serror, SCRIPT_ERR_DISABLED_OPCODE); // Disabled opcodes. + // With SCRIPT_VERIFY_CONST_SCRIPTCODE, OP_CODESEPARATOR in non-segwit script is rejected even in an unexecuted branch + if (opcode == OP_CODESEPARATOR && sigversion == SigVersion::BASE && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE)) + return set_error(serror, SCRIPT_ERR_OP_CODESEPARATOR); + if (fExec && 0 <= opcode && opcode <= OP_PUSHDATA4) { if (fRequireMinimal && !CheckMinimalPush(vchPushValue, opcode)) { return set_error(serror, SCRIPT_ERR_MINIMALDATA); @@ -899,6 +903,9 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& case OP_CODESEPARATOR: { + // If SCRIPT_VERIFY_CONST_SCRIPTCODE flag is set, use of OP_CODESEPARATOR is rejected in pre-segwit + // script, even in an unexecuted branch (this is checked above the opcode case statement). + // Hash starts after the code separator pbegincodehash = pc; } @@ -919,7 +926,9 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& // Drop the signature in pre-segwit scripts but not segwit scripts if (sigversion == SigVersion::BASE) { - FindAndDelete(scriptCode, CScript(vchSig)); + int found = FindAndDelete(scriptCode, CScript(vchSig)); + if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE)) + return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE); } if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) { @@ -983,7 +992,9 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& { valtype& vchSig = stacktop(-isig-k); if (sigversion == SigVersion::BASE) { - FindAndDelete(scriptCode, CScript(vchSig)); + int found = FindAndDelete(scriptCode, CScript(vchSig)); + if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE)) + return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE); } } diff --git a/src/script/interpreter.h b/src/script/interpreter.h index 50c747900a..2800473a68 100644 --- a/src/script/interpreter.h +++ b/src/script/interpreter.h @@ -111,6 +111,10 @@ enum // Public keys in segregated witness scripts must be compressed // SCRIPT_VERIFY_WITNESS_PUBKEYTYPE = (1U << 15), + + // Making OP_CODESEPARATOR and FindAndDelete fail any non-segwit scripts + // + SCRIPT_VERIFY_CONST_SCRIPTCODE = (1U << 16), }; bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror); diff --git a/src/script/script_error.cpp b/src/script/script_error.cpp index dbceb1f740..ceda740580 100644 --- a/src/script/script_error.cpp +++ b/src/script/script_error.cpp @@ -89,6 +89,10 @@ const char* ScriptErrorString(const ScriptError serror) return "Witness provided for non-witness script"; case SCRIPT_ERR_WITNESS_PUBKEYTYPE: return "Using non-compressed keys in segwit"; + case SCRIPT_ERR_OP_CODESEPARATOR: + return "Using OP_CODESEPARATOR in non-witness script"; + case SCRIPT_ERR_SIG_FINDANDDELETE: + return "Signature is found in scriptCode"; case SCRIPT_ERR_UNKNOWN_ERROR: case SCRIPT_ERR_ERROR_COUNT: default: break; diff --git a/src/script/script_error.h b/src/script/script_error.h index 3200e94707..6982a087f4 100644 --- a/src/script/script_error.h +++ b/src/script/script_error.h @@ -64,6 +64,10 @@ typedef enum ScriptError_t SCRIPT_ERR_WITNESS_UNEXPECTED, SCRIPT_ERR_WITNESS_PUBKEYTYPE, + /* Constant scriptCode */ + SCRIPT_ERR_OP_CODESEPARATOR, + SCRIPT_ERR_SIG_FINDANDDELETE, + SCRIPT_ERR_ERROR_COUNT } ScriptError; diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp index 068f1e66f4..39cca90e83 100644 --- a/src/test/script_tests.cpp +++ b/src/test/script_tests.cpp @@ -97,6 +97,8 @@ static ScriptErrorDesc script_errors[]={ {SCRIPT_ERR_WITNESS_MALLEATED_P2SH, "WITNESS_MALLEATED_P2SH"}, {SCRIPT_ERR_WITNESS_UNEXPECTED, "WITNESS_UNEXPECTED"}, {SCRIPT_ERR_WITNESS_PUBKEYTYPE, "WITNESS_PUBKEYTYPE"}, + {SCRIPT_ERR_OP_CODESEPARATOR, "OP_CODESEPARATOR"}, + {SCRIPT_ERR_SIG_FINDANDDELETE, "SIG_FINDANDDELETE"}, }; const char *FormatScriptError(ScriptError_t err) |