From 2851b77312b55c8868acd4cd2c118e5a034606b7 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Wed, 28 Jun 2017 15:49:13 -0700 Subject: [PATCH 1/3] Make all script verification flags softforks --- src/script/interpreter.cpp | 6 ------ src/script/interpreter.h | 23 ++++++++++++++--------- src/test/data/script_tests.json | 2 -- 3 files changed, 14 insertions(+), 17 deletions(-) diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp index 7149c938f..d90abdaf5 100644 --- a/src/script/interpreter.cpp +++ b/src/script/interpreter.cpp @@ -349,9 +349,6 @@ bool EvalScript(std::vector >& stack, const CScript& { if (!(flags & SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY)) { // not enabled; treat as a NOP2 - if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) { - return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS); - } break; } @@ -391,9 +388,6 @@ bool EvalScript(std::vector >& stack, const CScript& { if (!(flags & SCRIPT_VERIFY_CHECKSEQUENCEVERIFY)) { // not enabled; treat as a NOP3 - if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) { - return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS); - } break; } diff --git a/src/script/interpreter.h b/src/script/interpreter.h index ab1dc4e68..3e2757271 100644 --- a/src/script/interpreter.h +++ b/src/script/interpreter.h @@ -27,37 +27,40 @@ enum SIGHASH_ANYONECANPAY = 0x80, }; -/** Script verification flags */ +/** Script verification flags. + * + * All flags are intended to be soft forks: the set of acceptable scripts under + * flags (A | B) is a subset of the acceptable scripts under flag (A). + */ enum { SCRIPT_VERIFY_NONE = 0, - // Evaluate P2SH subscripts (softfork safe, BIP16). + // Evaluate P2SH subscripts (BIP16). SCRIPT_VERIFY_P2SH = (1U << 0), // Passing a non-strict-DER signature or one with undefined hashtype to a checksig operation causes script failure. // Evaluating a pubkey that is not (0x04 + 64 bytes) or (0x02 or 0x03 + 32 bytes) by checksig causes script failure. - // (softfork safe, but not used or intended as a consensus rule). + // (not used or intended as a consensus rule). SCRIPT_VERIFY_STRICTENC = (1U << 1), - // Passing a non-strict-DER signature to a checksig operation causes script failure (softfork safe, BIP62 rule 1) + // Passing a non-strict-DER signature to a checksig operation causes script failure (BIP62 rule 1) SCRIPT_VERIFY_DERSIG = (1U << 2), // Passing a non-strict-DER signature or one with S > order/2 to a checksig operation causes script failure - // (softfork safe, BIP62 rule 5). + // (BIP62 rule 5). SCRIPT_VERIFY_LOW_S = (1U << 3), - // verify dummy stack item consumed by CHECKMULTISIG is of zero-length (softfork safe, BIP62 rule 7). + // verify dummy stack item consumed by CHECKMULTISIG is of zero-length (BIP62 rule 7). SCRIPT_VERIFY_NULLDUMMY = (1U << 4), - // Using a non-push operator in the scriptSig causes script failure (softfork safe, BIP62 rule 2). + // Using a non-push operator in the scriptSig causes script failure (BIP62 rule 2). SCRIPT_VERIFY_SIGPUSHONLY = (1U << 5), // Require minimal encodings for all push operations (OP_0... OP_16, OP_1NEGATE where possible, direct // pushes up to 75 bytes, OP_PUSHDATA up to 255 bytes, OP_PUSHDATA2 for anything larger). Evaluating // any other push causes the script to fail (BIP62 rule 3). // In addition, whenever a stack element is interpreted as a number, it must be of minimal length (BIP62 rule 4). - // (softfork safe) SCRIPT_VERIFY_MINIMALDATA = (1U << 6), // Discourage use of NOPs reserved for upgrades (NOP1-10) @@ -68,12 +71,14 @@ enum // discouraged NOPs fails the script. This verification flag will never be // a mandatory flag applied to scripts in a block. NOPs that are not // executed, e.g. within an unexecuted IF ENDIF block, are *not* rejected. + // NOPs that have associated forks to give them new meaning (CLTV, CSV) + // are not subject to this rule. SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS = (1U << 7), // Require that only a single stack element remains after evaluation. This changes the success criterion from // "At least one stack element must remain, and when interpreted as a boolean, it must be true" to // "Exactly one stack element must remain, and when interpreted as a boolean, it must be true". - // (softfork safe, BIP62 rule 6) + // (BIP62 rule 6) // Note: CLEANSTACK should never be used without P2SH or WITNESS. SCRIPT_VERIFY_CLEANSTACK = (1U << 8), diff --git a/src/test/data/script_tests.json b/src/test/data/script_tests.json index 0390d6806..50aaa223f 100644 --- a/src/test/data/script_tests.json +++ b/src/test/data/script_tests.json @@ -862,8 +862,6 @@ ["Ensure 100% coverage of discouraged NOPS"], ["1", "NOP1", "P2SH,DISCOURAGE_UPGRADABLE_NOPS", "DISCOURAGE_UPGRADABLE_NOPS"], -["1", "CHECKLOCKTIMEVERIFY", "P2SH,DISCOURAGE_UPGRADABLE_NOPS", "DISCOURAGE_UPGRADABLE_NOPS"], -["1", "CHECKSEQUENCEVERIFY", "P2SH,DISCOURAGE_UPGRADABLE_NOPS", "DISCOURAGE_UPGRADABLE_NOPS"], ["1", "NOP4", "P2SH,DISCOURAGE_UPGRADABLE_NOPS", "DISCOURAGE_UPGRADABLE_NOPS"], ["1", "NOP5", "P2SH,DISCOURAGE_UPGRADABLE_NOPS", "DISCOURAGE_UPGRADABLE_NOPS"], ["1", "NOP6", "P2SH,DISCOURAGE_UPGRADABLE_NOPS", "DISCOURAGE_UPGRADABLE_NOPS"], From 2dd6f80680b8cbf9d4c99c6b2a8310af541e9aa3 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Wed, 28 Jun 2017 16:29:14 -0700 Subject: [PATCH 2/3] Add a test that all flags are softforks --- src/test/script_tests.cpp | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp index 1bb191c73..f1a3d2d03 100644 --- a/src/test/script_tests.cpp +++ b/src/test/script_tests.cpp @@ -167,6 +167,17 @@ void DoTest(const CScript& scriptPubKey, const CScript& scriptSig, const CScript CMutableTransaction tx2 = tx; BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, &scriptWitness, flags, MutableTransactionSignatureChecker(&tx, 0, txCredit.vout[0].nValue), &err) == expect, message); BOOST_CHECK_MESSAGE(err == scriptError, std::string(FormatScriptError(err)) + " where " + std::string(FormatScriptError((ScriptError_t)scriptError)) + " expected: " + message); + + // Verify that removing flags from a passing test or adding flags to a failing test does not change the result. + for (int i = 0; i < 16; ++i) { + int extra_flags = InsecureRandBits(16); + int combined_flags = expect ? (flags & ~extra_flags) : (flags | extra_flags); + // Weed out some invalid flag combinations. + if (combined_flags & SCRIPT_VERIFY_CLEANSTACK && ~combined_flags & (SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS)) continue; + if (combined_flags & SCRIPT_VERIFY_WITNESS && ~combined_flags & SCRIPT_VERIFY_P2SH) continue; + BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, &scriptWitness, combined_flags, MutableTransactionSignatureChecker(&tx, 0, txCredit.vout[0].nValue), &err) == expect, message + strprintf(" (with flags %x)", combined_flags)); + } + #if defined(HAVE_CONSENSUS_LIB) CDataStream stream(SER_NETWORK, PROTOCOL_VERSION); stream << tx2; From 01013f5d2fbe3fa86565c927bf7bb8ec0f525073 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Fri, 30 Jun 2017 16:18:57 -0700 Subject: [PATCH 3/3] Simplify tx validation tests --- src/test/txvalidationcache_tests.cpp | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) diff --git a/src/test/txvalidationcache_tests.cpp b/src/test/txvalidationcache_tests.cpp index a74f40251..e6d014af2 100644 --- a/src/test/txvalidationcache_tests.cpp +++ b/src/test/txvalidationcache_tests.cpp @@ -101,7 +101,7 @@ BOOST_FIXTURE_TEST_CASE(tx_mempool_block_doublespend, TestChain100Setup) // should fail. // Capture this interaction with the upgraded_nop argument: set it when evaluating // any script flag that is implemented as an upgraded NOP code. -void ValidateCheckInputsForAllFlags(CMutableTransaction &tx, uint32_t failing_flags, bool add_to_cache, bool upgraded_nop) +void ValidateCheckInputsForAllFlags(CMutableTransaction &tx, uint32_t failing_flags, bool add_to_cache) { PrecomputedTransactionData txdata(tx); // If we add many more flags, this loop can get too expensive, but we can @@ -122,12 +122,6 @@ void ValidateCheckInputsForAllFlags(CMutableTransaction &tx, uint32_t failing_fl // CheckInputs should succeed iff test_flags doesn't intersect with // failing_flags bool expected_return_value = !(test_flags & failing_flags); - if (expected_return_value && upgraded_nop) { - // If the script flag being tested corresponds to an upgraded NOP, - // then script execution should fail if DISCOURAGE_UPGRADABLE_NOPS - // is set. - expected_return_value = !(test_flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS); - } BOOST_CHECK_EQUAL(ret, expected_return_value); // Test the caching @@ -213,7 +207,7 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) // not present. Don't add these checks to the cache, so that we can // test later that block validation works fine in the absence of cached // successes. - ValidateCheckInputsForAllFlags(spend_tx, SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC, false, false); + ValidateCheckInputsForAllFlags(spend_tx, SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC, false); // And if we produce a block with this tx, it should be valid (DERSIG not // enabled yet), even though there's no cache entry. @@ -238,7 +232,7 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) std::vector vchSig2(p2pk_scriptPubKey.begin(), p2pk_scriptPubKey.end()); invalid_under_p2sh_tx.vin[0].scriptSig << vchSig2; - ValidateCheckInputsForAllFlags(invalid_under_p2sh_tx, SCRIPT_VERIFY_P2SH, true, false); + ValidateCheckInputsForAllFlags(invalid_under_p2sh_tx, SCRIPT_VERIFY_P2SH, true); } // Test CHECKLOCKTIMEVERIFY @@ -261,7 +255,7 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) vchSig.push_back((unsigned char)SIGHASH_ALL); invalid_with_cltv_tx.vin[0].scriptSig = CScript() << vchSig << 101; - ValidateCheckInputsForAllFlags(invalid_with_cltv_tx, SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY, true, true); + ValidateCheckInputsForAllFlags(invalid_with_cltv_tx, SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY, true); // Make it valid, and check again invalid_with_cltv_tx.vin[0].scriptSig = CScript() << vchSig << 100; @@ -289,7 +283,7 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) vchSig.push_back((unsigned char)SIGHASH_ALL); invalid_with_csv_tx.vin[0].scriptSig = CScript() << vchSig << 101; - ValidateCheckInputsForAllFlags(invalid_with_csv_tx, SCRIPT_VERIFY_CHECKSEQUENCEVERIFY, true, true); + ValidateCheckInputsForAllFlags(invalid_with_csv_tx, SCRIPT_VERIFY_CHECKSEQUENCEVERIFY, true); // Make it valid, and check again invalid_with_csv_tx.vin[0].scriptSig = CScript() << vchSig << 100; @@ -318,11 +312,11 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) UpdateTransaction(valid_with_witness_tx, 0, sigdata); // This should be valid under all script flags. - ValidateCheckInputsForAllFlags(valid_with_witness_tx, 0, true, false); + ValidateCheckInputsForAllFlags(valid_with_witness_tx, 0, true); // Remove the witness, and check that it is now invalid. valid_with_witness_tx.vin[0].scriptWitness.SetNull(); - ValidateCheckInputsForAllFlags(valid_with_witness_tx, SCRIPT_VERIFY_WITNESS, true, false); + ValidateCheckInputsForAllFlags(valid_with_witness_tx, SCRIPT_VERIFY_WITNESS, true); } { @@ -347,7 +341,7 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) } // This should be valid under all script flags - ValidateCheckInputsForAllFlags(tx, 0, true, false); + ValidateCheckInputsForAllFlags(tx, 0, true); // Check that if the second input is invalid, but the first input is // valid, the transaction is not cached.