Auto merge of #4966 - str4d:zcash-script-lib, r=nuttycom

Replace libzcashconsensus with libzcash_script

We inherited `libzcashconsensus` from upstream (we just renamed it before launch to avoid conflicts). However, it has become increasingly inaccurately named; it only covers (Zcash's subset of) the Bitcoin scripting system, and not the myriad of other consensus changes (in particular, the shielded pools).

This PR reworks the library to instead be focused on transparent script verification:
- The script verification APIs are altered to take `amount` and `consensusBranchId` fields.
- Equihash code is removed (the canonical Equihash validator is now the `equihash` Rust crate).
- The library is renamed to `libzcash_script`.

The API changes are backwards-incompatible, but the library rename prevents any issues. Also, `libzcashconsensus` was in fact broken and not compiling for several years and no one complained, suggesting that it was not actually being relied on within the ecosystem. By contrast, this focused library already has a consumer: the `zebrad` full node.

Closes zcash/zcash#4879.

.gitignore

@@ -112,7 +112,7 @@ qa/cache/*
 
 /doc/doxygen/
 
-libzcashconsensus.pc
+libzcash_script.pc
 
 contrib/debian/files
 contrib/debian/substvars

Makefile.am

@@ -19,7 +19,7 @@ GZIP_ENV="-9n"
 
 if BUILD_BITCOIN_LIBS
 pkgconfigdir = $(libdir)/pkgconfig
-pkgconfig_DATA = libzcashconsensus.pc
+pkgconfig_DATA = libzcash_script.pc
 endif
 
 BITCOIND_BIN=$(top_builddir)/src/$(BITCOIN_DAEMON_NAME)$(EXEEXT)

configure.ac

@@ -872,8 +872,8 @@ AC_MSG_RESULT($build_bitcoin_utils)
 AC_MSG_CHECKING([whether to build libraries])
 AM_CONDITIONAL([BUILD_BITCOIN_LIBS], [test x$build_bitcoin_libs = xyes])
 if test x$build_bitcoin_libs = xyes; then
-  AC_DEFINE(HAVE_CONSENSUS_LIB, 1, [Define this symbol if the consensus lib has been built])
+  AC_DEFINE(HAVE_SCRIPT_LIB, 1, [Define this symbol if the script lib has been built])
-  AC_CONFIG_FILES([libzcashconsensus.pc:libzcashconsensus.pc.in])
+  AC_CONFIG_FILES([libzcash_script.pc:libzcash_script.pc.in])
 fi
 
 AC_MSG_RESULT($build_bitcoin_libs)

libzcash_script.pc.in

@@ -0,0 +1,10 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: Zcash transparent script verification library
+Description: Library for verifying scripts against the Zcash consensus protocol.
+Version: @PACKAGE_VERSION@
+Libs: -L${libdir} -lzcash_script
+Cflags: -I${includedir}

libzcashconsensus.pc.in

@@ -1,10 +0,0 @@
-prefix=@prefix@
-exec_prefix=@exec_prefix@
-libdir=@libdir@
-includedir=@includedir@
-
-Name: Zcash consensus library
-Description: Library for the Zcash consensus protocol.
-Version: @PACKAGE_VERSION@
-Libs: -L${libdir} -lzcashconsensus
-Cflags: -I${includedir}

src/Makefile.am

@@ -33,7 +33,7 @@ if ENABLE_ZMQ
 LIBBITCOIN_ZMQ=libbitcoin_zmq.a
 endif
 if BUILD_BITCOIN_LIBS
-LIBZCASH_CONSENSUS=libzcashconsensus.la
+LIBZCASH_SCRIPT=libzcash_script.la
 endif
 if ENABLE_WALLET
 LIBBITCOIN_WALLET=libbitcoin_wallet.a
@@ -88,7 +88,7 @@ EXTRA_LIBRARIES += \
   $(LIBBITCOIN_ZMQ) \
   $(LIBZCASH)
 
-lib_LTLIBRARIES = $(LIBZCASH_CONSENSUS)
+lib_LTLIBRARIES = $(LIBZCASH_SCRIPT)
 
 bin_PROGRAMS =
 noinst_PROGRAMS =
@@ -543,11 +543,10 @@ libzcash_a_CPPFLAGS = $(AM_CPPFLAGS) $(PIC_FLAGS) $(BITCOIN_INCLUDES)
 libzcash_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 libzcash_a_LDFLAGS = $(AM_LDFLAGS)
 
-# zcashconsensus library #
+# zcash_script library #
 if BUILD_BITCOIN_LIBS
-include_HEADERS = script/zcashconsensus.h
+include_HEADERS = script/zcash_script.h
-libzcashconsensus_la_SOURCES = \
+libzcash_script_la_SOURCES = \
-  crypto/equihash.cpp \
   crypto/hmac_sha512.cpp \
   crypto/ripemd160.cpp \
   crypto/sha1.cpp \
@@ -556,20 +555,20 @@ libzcashconsensus_la_SOURCES = \
   hash.cpp \
   primitives/transaction.cpp \
   pubkey.cpp \
-  script/zcashconsensus.cpp \
+  script/zcash_script.cpp \
   script/interpreter.cpp \
   script/script.cpp \
   uint256.cpp \
   utilstrencodings.cpp
 
 if GLIBC_BACK_COMPAT
-  libzcashconsensus_la_SOURCES += compat/glibc_compat.cpp
+  libzcash_script_la_SOURCES += compat/glibc_compat.cpp
 endif
 
-libzcashconsensus_la_LDFLAGS = $(AM_LDFLAGS) -no-undefined $(RELDFLAGS)
+libzcash_script_la_LDFLAGS = $(AM_LDFLAGS) -no-undefined $(RELDFLAGS)
-libzcashconsensus_la_LIBADD = $(LIBSECP256K1)
+libzcash_script_la_LIBADD = $(LIBSECP256K1)
-libzcashconsensus_la_CPPFLAGS = $(AM_CPPFLAGS) -I$(builddir)/obj -I$(srcdir)/rust/include -I$(srcdir)/secp256k1/include -DBUILD_BITCOIN_INTERNAL
+libzcash_script_la_CPPFLAGS = $(AM_CPPFLAGS) -I$(builddir)/obj -I$(srcdir)/rust/include -I$(srcdir)/secp256k1/include -DBUILD_BITCOIN_INTERNAL
-libzcashconsensus_la_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+libzcash_script_la_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 
 endif
 #

src/Makefile.gtest.include

@@ -80,7 +80,7 @@ zcash_gtest_LDADD = \
   $(LIBSECP256K1)
 
 zcash_gtest_LDADD += \
-  $(LIBZCASH_CONSENSUS) \
+  $(LIBZCASH_SCRIPT) \
   $(BOOST_LIBS) \
   $(BOOST_UNIT_TEST_FRAMEWORK_LIB) \
   $(BDB_LIBS) \

src/Makefile.test.include

@@ -130,7 +130,7 @@ test_test_bitcoin_LDADD += $(LIBBITCOIN_SERVER) $(LIBBITCOIN_CLI) $(LIBBITCOIN_C
   $(LIBLEVELDB) $(LIBLEVELDB_SSE42) $(LIBMEMENV) $(BOOST_LIBS) $(BOOST_UNIT_TEST_FRAMEWORK_LIB) $(LIBSECP256K1) $(EVENT_LIBS) $(EVENT_PTHREADS_LIBS)
 test_test_bitcoin_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 
-test_test_bitcoin_LDADD += $(LIBZCASH_CONSENSUS) $(BDB_LIBS) $(LIBZCASH) $(LIBRUSTZCASH) $(LIBZCASH_LIBS)
+test_test_bitcoin_LDADD += $(LIBZCASH_SCRIPT) $(BDB_LIBS) $(LIBZCASH) $(LIBRUSTZCASH) $(LIBZCASH_LIBS)
 test_test_bitcoin_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS) -static
 
 if ENABLE_ZMQ

src/script/zcash_script.cpp

@@ -3,7 +3,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or https://www.opensource.org/licenses/mit-license.php .
 
-#include "zcashconsensus.h"
+#include "zcash_script.h"
 
 #include "consensus/upgrades.h"
 #include "primitives/transaction.h"
@@ -56,7 +56,7 @@ private:
     size_t m_remaining;
 };
 
-inline int set_error(zcashconsensus_error* ret, zcashconsensus_error serror)
+inline int set_error(zcash_script_error* ret, zcash_script_error serror)
 {
     if (ret)
         *ret = serror;
@@ -71,38 +71,40 @@ struct ECCryptoClosure
 ECCryptoClosure instance_of_eccryptoclosure;
 }
 
-int zcashconsensus_verify_script(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen,
+int zcash_script_verify(
-                                    const unsigned char *txTo        , unsigned int txToLen,
+    const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen,
-                                    unsigned int nIn, unsigned int flags, zcashconsensus_error* err)
+    int64_t amount,
+    const unsigned char *txTo, unsigned int txToLen,
+    unsigned int nIn, unsigned int flags,
+    uint32_t consensusBranchId,
+    zcash_script_error* err)
 {
     try {
         TxInputStream stream(SER_NETWORK, PROTOCOL_VERSION, txTo, txToLen);
         CTransaction tx;
         stream >> tx;
         if (nIn >= tx.vin.size())
-            return set_error(err, zcashconsensus_ERR_TX_INDEX);
+            return set_error(err, zcash_script_ERR_TX_INDEX);
         if (GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION) != txToLen)
-            return set_error(err, zcashconsensus_ERR_TX_SIZE_MISMATCH);
+            return set_error(err, zcash_script_ERR_TX_SIZE_MISMATCH);
 
          // Regardless of the verification result, the tx did not error.
-         set_error(err, zcashconsensus_ERR_OK);
+        set_error(err, zcash_script_ERR_OK);
         PrecomputedTransactionData txdata(tx);
-        CAmount am(0);
-        uint32_t consensusBranchId = SPROUT_BRANCH_ID;
         return VerifyScript(
             tx.vin[nIn].scriptSig,
             CScript(scriptPubKey, scriptPubKey + scriptPubKeyLen),
             flags,
-            TransactionSignatureChecker(&tx, nIn, am, txdata),
+            TransactionSignatureChecker(&tx, nIn, amount, txdata),
             consensusBranchId,
             NULL);
     } catch (const std::exception&) {
-        return set_error(err, zcashconsensus_ERR_TX_DESERIALIZE); // Error deserializing
+        return set_error(err, zcash_script_ERR_TX_DESERIALIZE); // Error deserializing
     }
 }
 
-unsigned int zcashconsensus_version()
+unsigned int zcash_script_version()
 {
     // Just use the API version for now
-    return ZCASHCONSENSUS_API_VER;
+    return ZCASH_SCRIPT_API_VER;
 }

src/script/zcash_script.h

@@ -33,33 +33,37 @@
 extern "C" {
 #endif
 
-#define ZCASHCONSENSUS_API_VER 0
+#define ZCASH_SCRIPT_API_VER 0
 
-typedef enum zcashconsensus_error_t
+typedef enum zcash_script_error_t
 {
-    zcashconsensus_ERR_OK = 0,
+    zcash_script_ERR_OK = 0,
-    zcashconsensus_ERR_TX_INDEX,
+    zcash_script_ERR_TX_INDEX,
-    zcashconsensus_ERR_TX_SIZE_MISMATCH,
+    zcash_script_ERR_TX_SIZE_MISMATCH,
-    zcashconsensus_ERR_TX_DESERIALIZE,
+    zcash_script_ERR_TX_DESERIALIZE,
-} zcashconsensus_error;
+} zcash_script_error;
 
 /** Script verification flags */
 enum
 {
-    zcashconsensus_SCRIPT_FLAGS_VERIFY_NONE                = 0,
+    zcash_script_SCRIPT_FLAGS_VERIFY_NONE                = 0,
-    zcashconsensus_SCRIPT_FLAGS_VERIFY_P2SH                = (1U << 0), // evaluate P2SH (BIP16) subscripts
+    zcash_script_SCRIPT_FLAGS_VERIFY_P2SH                = (1U << 0), // evaluate P2SH (BIP16) subscripts
-    zcashconsensus_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 9), // enable CHECKLOCKTIMEVERIFY (BIP65)
+    zcash_script_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 9), // enable CHECKLOCKTIMEVERIFY (BIP65)
 };
 
 /// Returns 1 if the input nIn of the serialized transaction pointed to by
 /// txTo correctly spends the scriptPubKey pointed to by scriptPubKey under
 /// the additional constraints specified by flags.
 /// If not NULL, err will contain an error/success code for the operation
-EXPORT_SYMBOL int zcashconsensus_verify_script(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen,
+EXPORT_SYMBOL int zcash_script_verify(
-                                    const unsigned char *txTo        , unsigned int txToLen,
+    const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen,
-                                    unsigned int nIn, unsigned int flags, zcashconsensus_error* err);
+    int64_t amount,
+    const unsigned char *txTo, unsigned int txToLen,
+    unsigned int nIn, unsigned int flags,
+    uint32_t consensusBranchId,
+    zcash_script_error* err);
 
-EXPORT_SYMBOL unsigned int zcashconsensus_version();
+EXPORT_SYMBOL unsigned int zcash_script_version();
 
 #ifdef __cplusplus
 } // extern "C"

src/test/script_tests.cpp

@@ -17,8 +17,8 @@
 #include "test/test_bitcoin.h"
 #include "test/test_util.h"
 
-#if defined(HAVE_CONSENSUS_LIB)
+#if defined(HAVE_SCRIPT_LIB)
-#include "script/zcashconsensus.h"
+#include "script/zcash_script.h"
 #endif
 
 #include <fstream>
@@ -81,10 +81,16 @@ void DoTest(const CScript& scriptPubKey, const CScript& scriptSig, int flags, ui
     CMutableTransaction tx2 = tx;
     BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, flags, MutableTransactionSignatureChecker(&tx, 0, txCredit.vout[0].nValue), consensusBranchId, &err) == expect, message);
     BOOST_CHECK_MESSAGE(expect == (err == SCRIPT_ERR_OK), std::string(ScriptErrorString(err)) + ": " + message);
-#if defined(HAVE_CONSENSUS_LIB)
+#if defined(HAVE_SCRIPT_LIB)
     CDataStream stream(SER_NETWORK, PROTOCOL_VERSION);
     stream << tx2;
-    BOOST_CHECK_MESSAGE(zcashconsensus_verify_script(begin_ptr(scriptPubKey), scriptPubKey.size(), (const unsigned char*)&stream[0], stream.size(), 0, flags, NULL) == expect,message);
+    BOOST_CHECK_MESSAGE(zcash_script_verify(
+        begin_ptr(scriptPubKey), scriptPubKey.size(),
+        txCredit.vout[0].nValue,
+        (const unsigned char*)&stream[0], stream.size(),
+        0, flags,
+        consensusBranchId,
+        NULL) == expect,message);
 #endif
 }
 

zcutil/make-release.py

@@ -276,7 +276,7 @@ def build():
         'Staging zeromq...',
         'Staging libsodium...',
         "Leaving directory '%s'" % depends_dir,
-        'config.status: creating libzcashconsensus.pc',
+        'config.status: creating libzcash_script.pc',
         "Entering directory '%s'" % src_dir,
         'httpserver.cpp',
         'torcontrol.cpp',