Merge #9172: Resurrect pstratem's "Simple fuzzing framework"

8b15434 doc: Add bare-bones documentation for fuzzing (Wladimir J. van der Laan)
a4153e2 Simple fuzzing framework (Patrick Strateman)

.gitignore

@@ -6,6 +6,7 @@ src/bitcoind
 src/bitcoin-cli
 src/bitcoin-tx
 src/test/test_bitcoin
+src/test/test_bitcoin_fuzzy
 src/qt/test/test_bitcoin-qt
 
 # autoreconf

doc/README.md

@@ -68,6 +68,7 @@ The Bitcoin repo's [root README](/README.md) contains relevant information on th
 ### Miscellaneous
 - [Assets Attribution](assets-attribution.md)
 - [Files](files.md)
+- [Fuzz-testing](fuzzing.md)
 - [Reduce Traffic](reduce-traffic.md)
 - [Tor Support](tor.md)
 - [Init Scripts (systemd/upstart/openrc)](init.md)

doc/fuzzing.md

@@ -0,0 +1,66 @@
+Fuzz-testing Bitcoin Core
+==========================
+
+A special test harness `test_bitcoin_fuzzy` is provided to provide an easy
+entry point for fuzzers and the like. In this document we'll describe how to
+use it with AFL.
+
+Building AFL
+-------------
+
+It is recommended to always use the latest version of afl:
+```
+wget http://lcamtuf.coredump.cx/afl/releases/afl-latest.tgz
+tar -zxvf afl-latest.tgz
+cd afl-<version>
+make
+export AFLPATH=$PWD
+```
+
+Instrumentation
+----------------
+
+To build Bitcoin Core using AFL instrumentation (this assumes that the
+`AFLPATH` was set as above):
+```
+./configure --disable-ccache --disable-shared --enable-tests CC=${AFLPATH}/afl-gcc CXX=${AFLPATH}/afl-g++
+export AFL_HARDEN=1
+cd src/
+make test/test_bitcoin_fuzzy
+```
+We disable ccache because we don't want to pollute the ccache with instrumented
+objects, and similarly don't want to use non-instrumented cached objects linked
+in.
+
+Preparing fuzzing
+------------------
+
+AFL needs an input directory with examples, and an output directory where it
+will place examples that it found. These can be anywhere in the file system,
+we'll define environment variables to make it easy to reference them.
+
+```
+mkdir inputs
+AFLIN=$PWD/inputs
+mkdir outputs
+AFLOUT=$PWD/outputs
+```
+
+Example inputs are available from:
+
+- https://download.visucore.com/bitcoin/bitcoin_fuzzy_in.tar.xz
+- http://strateman.ninja/fuzzing.tar.xz
+
+Extract these (or other starting inputs) into the `inputs` directory before starting fuzzing.
+
+Fuzzing
+--------
+
+To start the actual fuzzing use:
+```
+$AFLPATH/afl-fuzz -i ${AFLIN} -o ${AFLOUT} -m52 -- test/test_bitcoin_fuzzy
+```
+
+You may have to change a few kernel parameters to test optimally - `afl-fuzz`
+will print an error and suggestion if so.
+

src/Makefile.am

@@ -61,6 +61,7 @@ EXTRA_LIBRARIES += \
 lib_LTLIBRARIES = $(LIBBITCOINCONSENSUS)
 
 bin_PROGRAMS =
+noinst_PROGRAMS =
 TESTS =
 BENCHMARKS =
 

src/Makefile.test.include

@@ -4,6 +4,7 @@
 
 TESTS += test/test_bitcoin
 bin_PROGRAMS += test/test_bitcoin
+noinst_PROGRAMS += test/test_bitcoin_fuzzy
 TEST_SRCDIR = test
 TEST_BINARY=test/test_bitcoin$(EXEEXT)
 
@@ -38,6 +39,7 @@ RAW_TEST_FILES =
 
 GENERATED_TEST_FILES = $(JSON_TEST_FILES:.json=.json.h) $(RAW_TEST_FILES:.raw=.raw.h)
 
+# test_bitcoin binary #
 BITCOIN_TESTS =\
   test/arith_uint256_tests.cpp \
   test/scriptnum10.h \
@@ -120,6 +122,25 @@ test_test_bitcoin_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS) -s
 if ENABLE_ZMQ
 test_test_bitcoin_LDADD += $(ZMQ_LIBS)
 endif
+#
+
+# test_bitcoin_fuzzy binary #
+test_test_bitcoin_fuzzy_SOURCES = test/test_bitcoin_fuzzy.cpp
+test_test_bitcoin_fuzzy_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
+test_test_bitcoin_fuzzy_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+test_test_bitcoin_fuzzy_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
+
+test_test_bitcoin_fuzzy_LDADD = \
+  $(LIBUNIVALUE) \
+  $(LIBBITCOIN_SERVER) \
+  $(LIBBITCOIN_COMMON) \
+  $(LIBBITCOIN_UTIL) \
+  $(LIBBITCOIN_CONSENSUS) \
+  $(LIBBITCOIN_CRYPTO) \
+  $(LIBSECP256K1)
+
+test_test_bitcoin_fuzzy_LDADD += $(BOOST_LIBS) $(CRYPTO_LIBS)
+#
 
 nodist_test_test_bitcoin_SOURCES = $(GENERATED_TEST_FILES)
 

src/test/test_bitcoin_fuzzy.cpp

@@ -0,0 +1,256 @@
+// Copyright (c) 2009-2015 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#if defined(HAVE_CONFIG_H)
+#include "config/bitcoin-config.h"
+#endif
+
+#include "consensus/merkle.h"
+#include "primitives/block.h"
+#include "script/script.h"
+#include "addrman.h"
+#include "chain.h"
+#include "coins.h"
+#include "compressor.h"
+#include "net.h"
+#include "protocol.h"
+#include "streams.h"
+#include "undo.h"
+#include "version.h"
+
+#include <stdint.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <vector>
+
+enum TEST_ID {
+    CBLOCK_DESERIALIZE=0,
+    CTRANSACTION_DESERIALIZE,
+    CBLOCKLOCATOR_DESERIALIZE,
+    CBLOCKMERKLEROOT,
+    CADDRMAN_DESERIALIZE,
+    CBLOCKHEADER_DESERIALIZE,
+    CBANENTRY_DESERIALIZE,
+    CTXUNDO_DESERIALIZE,
+    CBLOCKUNDO_DESERIALIZE,
+    CCOINS_DESERIALIZE,
+    CNETADDR_DESERIALIZE,
+    CSERVICE_DESERIALIZE,
+    CMESSAGEHEADER_DESERIALIZE,
+    CADDRESS_DESERIALIZE,
+    CINV_DESERIALIZE,
+    CBLOOMFILTER_DESERIALIZE,
+    CDISKBLOCKINDEX_DESERIALIZE,
+    CTXOUTCOMPRESSOR_DESERIALIZE,
+    TEST_ID_END
+};
+
+bool read_stdin(std::vector<char> &data) {
+    char buffer[1024];
+    ssize_t length=0;
+    while((length = read(STDIN_FILENO, buffer, 1024)) > 0) {
+        data.insert(data.end(), buffer, buffer+length);
+
+        if (data.size() > (1<<20)) return false;
+    }
+    return length==0;
+}
+
+int main(int argc, char **argv)
+{
+    std::vector<char> buffer;
+    if (!read_stdin(buffer)) return 0;
+
+    if (buffer.size() < sizeof(uint32_t)) return 0;
+
+    uint32_t test_id = 0xffffffff;
+    memcpy(&test_id, &buffer[0], sizeof(uint32_t));
+    buffer.erase(buffer.begin(), buffer.begin() + sizeof(uint32_t));
+
+    if (test_id >= TEST_ID_END) return 0;
+
+    CDataStream ds(buffer, SER_NETWORK, INIT_PROTO_VERSION);
+    try {
+        int nVersion;
+        ds >> nVersion;
+        ds.SetVersion(nVersion);
+    } catch (const std::ios_base::failure& e) {
+        return 0;
+    }
+
+    switch(test_id) {
+        case CBLOCK_DESERIALIZE:
+        {
+            try
+            {
+                CBlock block;
+                ds >> block;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CTRANSACTION_DESERIALIZE:
+        {
+            try
+            {
+                CTransaction tx(deserialize, ds);
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CBLOCKLOCATOR_DESERIALIZE:
+        {
+            try
+            {
+                CBlockLocator bl;
+                ds >> bl;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CBLOCKMERKLEROOT:
+        {
+            try
+            {
+                CBlock block;
+                ds >> block;
+                bool mutated;
+                BlockMerkleRoot(block, &mutated);
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CADDRMAN_DESERIALIZE:
+        {
+            try
+            {
+                CAddrMan am;
+                ds >> am;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CBLOCKHEADER_DESERIALIZE:
+        {
+            try
+            {
+                CBlockHeader bh;
+                ds >> bh;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CBANENTRY_DESERIALIZE:
+        {
+            try
+            {
+                CBanEntry be;
+                ds >> be;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CTXUNDO_DESERIALIZE:
+        {
+            try
+            {
+                CTxUndo tu;
+                ds >> tu;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CBLOCKUNDO_DESERIALIZE:
+        {
+            try
+            {
+                CBlockUndo bu;
+                ds >> bu;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CCOINS_DESERIALIZE:
+        {
+            try
+            {
+                CCoins block;
+                ds >> block;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CNETADDR_DESERIALIZE:
+        {
+            try
+            {
+                CNetAddr na;
+                ds >> na;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CSERVICE_DESERIALIZE:
+        {
+            try
+            {
+                CService s;
+                ds >> s;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CMESSAGEHEADER_DESERIALIZE:
+        {
+            CMessageHeader::MessageStartChars pchMessageStart = {0x00, 0x00, 0x00, 0x00};
+            try
+            {
+                CMessageHeader mh(pchMessageStart);
+                ds >> mh;
+                if (!mh.IsValid(pchMessageStart)) {return 0;}
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CADDRESS_DESERIALIZE:
+        {
+            try
+            {
+                CAddress a;
+                ds >> a;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CINV_DESERIALIZE:
+        {
+            try
+            {
+                CInv i;
+                ds >> i;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CBLOOMFILTER_DESERIALIZE:
+        {
+            try
+            {
+                CBloomFilter bf;
+                ds >> bf;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CDISKBLOCKINDEX_DESERIALIZE:
+        {
+            try
+            {
+                CDiskBlockIndex dbi;
+                ds >> dbi;
+            } catch (const std::ios_base::failure& e) {return 0;}
+            break;
+        }
+        case CTXOUTCOMPRESSOR_DESERIALIZE:
+        {
+            CTxOut to;
+            try
+            {
+                ds >> to;
+            } catch (const std::ios_base::failure& e) {return 0;}
+
+            CTxOutCompressor toc(to);
+            break;
+        }
+        default:
+            return 0;
+    }
+    return 0;
+}
+