diff --git a/src/main.cpp b/src/main.cpp index e7a7140a916..41322d6a801 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -792,7 +792,7 @@ bool CTxMemPool::accept(CValidationState &state, CTransaction &tx, bool fCheckIn // Check against previous transactions // This is done last to help prevent CPU exhaustion denial-of-service attacks. - if (!tx.CheckInputs(state, view, true, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC)) + if (!tx.CheckInputs(state, view, true, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC | SCRIPT_VERIFY_DERSIG)) { return error("CTxMemPool::accept() : ConnectInputs failed %s", hash.ToString().c_str()); } @@ -1645,6 +1645,12 @@ bool CBlock::ConnectBlock(CValidationState &state, CBlockIndex* pindex, CCoinsVi unsigned int flags = SCRIPT_VERIFY_NOCACHE | (fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE); + if (nVersion >= 3 && + ((!fTestNet && CBlockIndex::IsSuperMajority(3, pindex->pprev, 750, 1000)) || + (fTestNet && CBlockIndex::IsSuperMajority(3, pindex->pprev, 51, 100)))) { + flags |= SCRIPT_VERIFY_DERSIG; + } + CBlockUndo blockundo; CCheckQueueControl control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : NULL); @@ -2193,6 +2199,15 @@ bool CBlock::AcceptBlock(CValidationState &state, CDiskBlockPos *dbp) return state.Invalid(error("AcceptBlock() : rejected nVersion=1 block")); } } + // Reject block.nVersion=2 blocks when 95% (75% on testnet) of the network has upgraded: + if (nVersion < 3) + { + if ((!fTestNet && CBlockIndex::IsSuperMajority(3, pindexPrev, 950, 1000)) || + (fTestNet && CBlockIndex::IsSuperMajority(3, pindexPrev, 75, 100))) + { + return state.Invalid(error("AcceptBlock() : rejected nVersion=2 block")); + } + } // Enforce block.nVersion=2 rule that the coinbase starts with serialized block height if (nVersion >= 2) { diff --git a/src/main.h b/src/main.h index 6665e5af021..82d40787a31 100644 --- a/src/main.h +++ b/src/main.h @@ -1268,7 +1268,7 @@ class CBlockHeader { public: // header - static const int CURRENT_VERSION=2; + static const int CURRENT_VERSION=3; int nVersion; uint256 hashPrevBlock; uint256 hashMerkleRoot; diff --git a/src/script.cpp b/src/script.cpp index 90066efd336..8a61716e935 100644 --- a/src/script.cpp +++ b/src/script.cpp @@ -289,6 +289,86 @@ bool IsCanonicalSignature(const valtype &vchSig) { return true; } +// BIP 66 defined signature encoding check. This largely overlaps with +// IsCanonicalSignature above, but lacks hashtype constraints, and uses the +// exact implementation code from BIP 66. +bool static IsValidSignatureEncoding(const std::vector &sig) { + // Format: 0x30 [total-length] 0x02 [R-length] [R] 0x02 [S-length] [S] [sighash] + // * total-length: 1-byte length descriptor of everything that follows, + // excluding the sighash byte. + // * R-length: 1-byte length descriptor of the R value that follows. + // * R: arbitrary-length big-endian encoded R value. It must use the shortest + // possible encoding for a positive integers (which means no null bytes at + // the start, except a single one when the next byte has its highest bit set). + // * S-length: 1-byte length descriptor of the S value that follows. + // * S: arbitrary-length big-endian encoded S value. The same rules apply. + // * sighash: 1-byte value indicating what data is hashed (not part of the DER + // signature) + + // Minimum and maximum size constraints. + if (sig.size() < 9) return false; + if (sig.size() > 73) return false; + + // A signature is of type 0x30 (compound). + if (sig[0] != 0x30) return false; + + // Make sure the length covers the entire signature. + if (sig[1] != sig.size() - 3) return false; + + // Extract the length of the R element. + unsigned int lenR = sig[3]; + + // Make sure the length of the S element is still inside the signature. + if (5 + lenR >= sig.size()) return false; + + // Extract the length of the S element. + unsigned int lenS = sig[5 + lenR]; + + // Verify that the length of the signature matches the sum of the length + // of the elements. + if ((size_t)(lenR + lenS + 7) != sig.size()) return false; + + // Check whether the R element is an integer. + if (sig[2] != 0x02) return false; + + // Zero-length integers are not allowed for R. + if (lenR == 0) return false; + + // Negative numbers are not allowed for R. + if (sig[4] & 0x80) return false; + + // Null bytes at the start of R are not allowed, unless R would + // otherwise be interpreted as a negative number. + if (lenR > 1 && (sig[4] == 0x00) && !(sig[5] & 0x80)) return false; + + // Check whether the S element is an integer. + if (sig[lenR + 4] != 0x02) return false; + + // Zero-length integers are not allowed for S. + if (lenS == 0) return false; + + // Negative numbers are not allowed for S. + if (sig[lenR + 6] & 0x80) return false; + + // Null bytes at the start of S are not allowed, unless S would otherwise be + // interpreted as a negative number. + if (lenS > 1 && (sig[lenR + 6] == 0x00) && !(sig[lenR + 7] & 0x80)) return false; + + return true; +} + +bool static CheckSignatureEncoding(const valtype &vchSig, unsigned int flags) { + // Empty signature. Not strictly DER encoded, but allowed to provide a + // compact way to provide an invalid signature for use with CHECK(MULTI)SIG + if (vchSig.size() == 0) { + return true; + } + if ((flags & SCRIPT_VERIFY_DERSIG) != 0 && !IsValidSignatureEncoding(vchSig)) { + return false; + } + return true; +} + bool EvalScript(vector >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType) { CAutoBN_CTX pctx; @@ -841,6 +921,10 @@ bool EvalScript(vector >& stack, const CScript& script, co // Drop the signature, since there's no way for a signature to sign itself scriptCode.FindAndDelete(CScript(vchSig)); + if (!CheckSignatureEncoding(vchSig, flags)) { + return false; + } + bool fSuccess = (!fStrictEncodings || (IsCanonicalSignature(vchSig) && IsCanonicalPubKey(vchPubKey))); if (fSuccess) fSuccess = CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType, flags); @@ -902,6 +986,10 @@ bool EvalScript(vector >& stack, const CScript& script, co valtype& vchSig = stacktop(-isig); valtype& vchPubKey = stacktop(-ikey); + if (!CheckSignatureEncoding(vchSig, flags)) { + return false; + } + // Check signature bool fOk = (!fStrictEncodings || (IsCanonicalSignature(vchSig) && IsCanonicalPubKey(vchPubKey))); if (fOk) diff --git a/src/script.h b/src/script.h index 4b29f6273c9..6a843437521 100644 --- a/src/script.h +++ b/src/script.h @@ -35,6 +35,7 @@ enum SCRIPT_VERIFY_P2SH = (1U << 0), SCRIPT_VERIFY_STRICTENC = (1U << 1), SCRIPT_VERIFY_NOCACHE = (1U << 2), + SCRIPT_VERIFY_DERSIG = (1U << 3), // enforce signature encodings as defined by BIP 66 (which is a softfork, while STRICTENC is not) }; enum txnouttype diff --git a/src/test/data/script_invalid.json b/src/test/data/script_invalid.json index 95664226c51..f1c68da1783 100644 --- a/src/test/data/script_invalid.json +++ b/src/test/data/script_invalid.json @@ -310,5 +310,45 @@ ["NOP1 0x01 1", "HASH160 0x14 0xda1745e9b549bd0bfa1a569971c77eba30cd5a4b EQUAL"], ["0 0x01 0x50", "HASH160 0x14 0xece424a6bb6ddf4db592c0faed60685047a361b1 EQUAL", "OP_RESERVED in P2SH should fail"], -["0 0x01 VER", "HASH160 0x14 0x0f4d7845db968f2a81b530b6f3c1d6246d4c7e01 EQUAL", "OP_VER in P2SH should fail"] +["0 0x01 VER", "HASH160 0x14 0x0f4d7845db968f2a81b530b6f3c1d6246d4c7e01 EQUAL", "OP_VER in P2SH should fail"], + +["0x4a 0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", "0 CHECKSIG NOT", "DERSIG", "Overly long signature is incorrectly encoded for DERSIG"], +["0x25 0x30220220000000000000000000000000000000000000000000000000000000000000000000", "0 CHECKSIG NOT", "DERSIG", "Missing S is incorrectly encoded for DERSIG"], +["0x27 0x3024021077777777777777777777777777777777020a7777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "S with invalid S length is incorrectly encoded for DERSIG"], +["0x27 0x302403107777777777777777777777777777777702107777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "Non-integer R is incorrectly encoded for DERSIG"], +["0x27 0x302402107777777777777777777777777777777703107777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "Non-integer S is incorrectly encoded for DERSIG"], +["0x17 0x3014020002107777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "Zero-length R is incorrectly encoded for DERSIG"], +["0x17 0x3014021077777777777777777777777777777777020001", "0 CHECKSIG NOT", "DERSIG", "Zero-length S is incorrectly encoded for DERSIG"], +["0x27 0x302402107777777777777777777777777777777702108777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "Negative S is incorrectly encoded for DERSIG"], + +[ + "0x47 0x30440220003040725f724b0e2142fc44ac71f6e13161f6410aeb6dee477952ede3b6a6ca022041ff4940ee3d88116ad281d7cc556e1f2c9427d82290bd7974a25addbcd5bede01", + "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG NOT", + "DERSIG", + "P2PK NOT with bad sig with too much R padding" +], +[ + "0x47 0x30440220003040725f724a0e2142fc44ac71f6e13161f6410aeb6dee477952ede3b6a6ca022041ff4940ee3d88116ad281d7cc556e1f2c9427d82290bd7974a25addbcd5bede01", + "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG NOT", + "DERSIG", + "P2PK NOT with too much R padding" +], +[ + "0x47 0x304402208e43c0b91f7c1e5bc58e41c8185f8a6086e111b0090187968a86f2822462d3c902200a58f4076b1133b18ff1dc83ee51676e44c60cc608d9534e0df5ace0424fc0be01", + "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT", + "DERSIG", + "BIP66 example 2, with DERSIG" +], +[ + "1", + "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT", + "DERSIG", + "BIP66 example 6, with DERSIG" +], +[ + "0 0 0x47 0x30440220afa76a8f60622f813b05711f051c6c3407e32d1b1b70b0576c1f01b54e4c05c702200d58e9df044fd1845cabfbeef6e624ba0401daf7d7e084736f9ff601c3783bf501", + "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT", + "DERSIG", + "BIP66 example 10, with DERSIG" +] ] diff --git a/src/test/data/script_valid.json b/src/test/data/script_valid.json index 58682d38751..1af06e1287b 100644 --- a/src/test/data/script_valid.json +++ b/src/test/data/script_valid.json @@ -375,5 +375,65 @@ ["NOP", "NOP10 1"], ["0 0x01 1", "HASH160 0x14 0xda1745e9b549bd0bfa1a569971c77eba30cd5a4b EQUAL", "Very basic P2SH"], -["0x4c 0 0x01 1", "HASH160 0x14 0xda1745e9b549bd0bfa1a569971c77eba30cd5a4b EQUAL"] +["0x4c 0 0x01 1", "HASH160 0x14 0xda1745e9b549bd0bfa1a569971c77eba30cd5a4b EQUAL"], + +["0x40 0x42424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242", +"0x4d 0x4000 0x42424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242 EQUAL", +"Basic PUSH signedness check"], + +["0x4c 0x40 0x42424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242", +"0x4d 0x4000 0x42424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242 EQUAL", +"Basic PUSHDATA1 signedness check"], + +["0x4a 0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", "0 CHECKSIG NOT", "", "Overly long signature is correctly encoded"], +["0x25 0x30220220000000000000000000000000000000000000000000000000000000000000000000", "0 CHECKSIG NOT", "", "Missing S is correctly encoded"], +["0x27 0x3024021077777777777777777777777777777777020a7777777777777777777777777777777701", "0 CHECKSIG NOT", "", "S with invalid S length is correctly encoded"], +["0x27 0x302403107777777777777777777777777777777702107777777777777777777777777777777701", "0 CHECKSIG NOT", "", "Non-integer R is correctly encoded"], +["0x27 0x302402107777777777777777777777777777777703107777777777777777777777777777777701", "0 CHECKSIG NOT", "", "Non-integer S is correctly encoded"], +["0x17 0x3014020002107777777777777777777777777777777701", "0 CHECKSIG NOT", "", "Zero-length R is correctly encoded"], +["0x17 0x3014021077777777777777777777777777777777020001", "0 CHECKSIG NOT", "", "Zero-length S is correctly encoded"], +["0x27 0x302402107777777777777777777777777777777702108777777777777777777777777777777701", "0 CHECKSIG NOT", "", "Negative S is correctly encoded"], + +[ + "0x47 0x30440220003040725f724b0e2142fc44ac71f6e13161f6410aeb6dee477952ede3b6a6ca022041ff4940ee3d88116ad281d7cc556e1f2c9427d82290bd7974a25addbcd5bede01", + "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG NOT", + "", + "P2PK NOT with bad sig with too much R padding but no DERSIG" +], +[ + "0", + "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT", + "", + "BIP66 example 4, without DERSIG" +], +[ + "0", + "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT", + "DERSIG", + "BIP66 example 4, with DERSIG" +], +[ + "1", + "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT", + "", + "BIP66 example 6, without DERSIG" +], +[ + "0 0 0x47 0x30440220afa76a8f60622f813b05711f051c6c3407e32d1b1b70b0576c1f01b54e4c05c702200d58e9df044fd1845cabfbeef6e624ba0401daf7d7e084736f9ff601c3783bf501", + "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT", + "", + "BIP66 example 10, without DERSIG" +], +[ + "0 0x47 0x30440220f00a77260d34ec2f0c59621dc710f58169d0ca06df1a88cd4b1f1b97bd46991b02201ee220c7e04f26aed03f94aa97fb09ca5627163bf4ba07e6979972ec737db22601 0", + "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT", + "", + "BIP66 example 12, without DERSIG" +], +[ + "0 0x47 0x30440220f00a77260d34ec2f0c59621dc710f58169d0ca06df1a88cd4b1f1b97bd46991b02201ee220c7e04f26aed03f94aa97fb09ca5627163bf4ba07e6979972ec737db22601 0", + "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT", + "DERSIG", + "BIP66 example 12, with DERSIG" +] ] diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp index 5d5a1525f76..ee81dbcdc27 100644 --- a/src/test/script_tests.cpp +++ b/src/test/script_tests.cpp @@ -142,8 +142,13 @@ BOOST_AUTO_TEST_CASE(script_valid) string scriptPubKeyString = test[1].get_str(); CScript scriptPubKey = ParseScript(scriptPubKeyString); + int flagsNow = flags; + if (test.size() > 3 && ("," + test[2].get_str() + ",").find(",DERSIG,") != string::npos) { + flagsNow |= SCRIPT_VERIFY_DERSIG; + } + CTransaction tx; - BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, tx, 0, flags, SIGHASH_NONE), strTest); + BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, tx, 0, flagsNow, SIGHASH_NONE), strTest); } } @@ -166,8 +171,13 @@ BOOST_AUTO_TEST_CASE(script_invalid) string scriptPubKeyString = test[1].get_str(); CScript scriptPubKey = ParseScript(scriptPubKeyString); + int flagsNow = flags; + if (test.size() > 3 && ("," + test[2].get_str() + ",").find(",DERSIG,") != string::npos) { + flagsNow |= SCRIPT_VERIFY_DERSIG; + } + CTransaction tx; - BOOST_CHECK_MESSAGE(!VerifyScript(scriptSig, scriptPubKey, tx, 0, flags, SIGHASH_NONE), strTest); + BOOST_CHECK_MESSAGE(!VerifyScript(scriptSig, scriptPubKey, tx, 0, flagsNow, SIGHASH_NONE), strTest); } }