diff --git a/Makefile.am b/Makefile.am
index d70058df..47475bca 100755
--- a/Makefile.am
+++ b/Makefile.am
@@ -1106,6 +1106,41 @@ tests_test_disconnect_msg_LDADD = ${TESTUTIL_LIBS} src/libzmq.la
tests_test_disconnect_msg_CPPFLAGS = ${TESTUTIL_CPPFLAGS}
endif
+if FUZZING_ENGINE_LIB
+fuzzer_apps = tests/test_bind_null_fuzzer \
+ tests/test_connect_null_fuzzer
+
+tests_test_bind_null_fuzzer_DEPENDENCIES = src/libzmq.la
+tests_test_bind_null_fuzzer_SOURCES = tests/test_bind_null_fuzzer.cpp
+tests_test_bind_null_fuzzer_LDADD = ${TESTUTIL_LIBS} ${FUZZING_ENGINE_LIB} \
+ $(top_builddir)/src/.libs/libzmq.a \
+ ${src_libzmq_la_LIBADD}
+tests_test_bind_null_fuzzer_CPPFLAGS = ${TESTUTIL_CPPFLAGS}
+tests_test_bind_null_fuzzer_CXXFLAGS = -std=c++11
+
+tests_test_connect_null_fuzzer_DEPENDENCIES = src/libzmq.la
+tests_test_connect_null_fuzzer_SOURCES = tests/test_connect_null_fuzzer.cpp
+tests_test_connect_null_fuzzer_LDADD = ${TESTUTIL_LIBS} ${FUZZING_ENGINE_LIB} \
+ $(top_builddir)/src/.libs/libzmq.a \
+ ${src_libzmq_la_LIBADD}
+tests_test_connect_null_fuzzer_CPPFLAGS = ${TESTUTIL_CPPFLAGS}
+tests_test_connect_null_fuzzer_CXXFLAGS = -std=c++11
+
+FUZZINGdir = ${prefix}/${FUZZING_INSTALLDIR}
+FUZZING_PROGRAMS = ${fuzzer_apps}
+else
+test_apps += tests/test_bind_null_fuzzer \
+ tests/test_connect_null_fuzzer
+
+tests_test_bind_null_fuzzer_SOURCES = tests/test_bind_null_fuzzer.cpp
+tests_test_bind_null_fuzzer_LDADD = ${TESTUTIL_LIBS} src/libzmq.la
+tests_test_bind_null_fuzzer_CPPFLAGS = ${TESTUTIL_CPPFLAGS}
+
+tests_test_connect_null_fuzzer_SOURCES = tests/test_connect_null_fuzzer.cpp
+tests_test_connect_null_fuzzer_LDADD = ${TESTUTIL_LIBS} src/libzmq.la
+tests_test_connect_null_fuzzer_CPPFLAGS = ${TESTUTIL_CPPFLAGS}
+endif
+
if ENABLE_STATIC
# unit tests - these include individual source files and test the internal functions
test_apps += \
diff --git a/configure.ac b/configure.ac
index aa532a77..ab0ed176 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1005,6 +1005,25 @@ AM_CONDITIONAL([WITH_CLANG_FORMAT], [$WITH_CLANG_FORMAT])
# unittests will not build without the static libzmq.a
AM_CONDITIONAL(ENABLE_STATIC, test "x$enable_static" = "xyes")
+# build using a fuzzing engine - fuzzers will be built separately and statically
+AC_ARG_WITH([fuzzing-engine], [AS_HELP_STRING([--with-fuzzing-engine],
+ [build libzmq with an exernal fuzzing engine [default=no]])],
+ [have_fuzzing_engine_ext=$withval],
+ [have_fuzzing_engine_ext=no])
+AC_ARG_WITH([fuzzing-installdir],
+ AS_HELP_STRING([--with-fuzzing-installdir=PATH],
+ [Path where to install fuzzer binaries]),
+ [fuzzing_installdir="$withval"])
+
+if test "x$have_fuzzing_engine_ext" != "xno" && test "x$fuzzing_installdir" != "x" && test "x$enable_static" = "xyes"; then
+ FUZZING_ENGINE_LIB="${have_fuzzing_engine_ext}"
+ FUZZING_INSTALLDIR="${fuzzing_installdir}"
+ AC_SUBST(FUZZING_ENGINE_LIB)
+ AC_SUBST(FUZZING_INSTALLDIR)
+ AC_DEFINE(ZMQ_USE_FUZZING_ENGINE, 1, [fuzz tests will be built with fuzzing engine])
+fi
+AM_CONDITIONAL(FUZZING_ENGINE_LIB, test "x$FUZZING_ENGINE_LIB" != "x")
+
# clang 6 has a warning that does not make sense on multi-platform code
AC_LANG_PUSH([C])
AX_CHECK_COMPILE_FLAG([-Wno-tautological-constant-compare],
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 10e91ed4..a77b52b4 100755
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -75,7 +75,7 @@ set(tests
test_mock_pub_sub)
if(NOT WIN32)
- list(APPEND tests test_security_gssapi test_socks)
+ list(APPEND tests test_security_gssapi test_socks test_connect_null_fuzzer test_bind_null_fuzzer)
endif()
if(ZMQ_HAVE_CURVE)
diff --git a/tests/test_bind_null_fuzzer.cpp b/tests/test_bind_null_fuzzer.cpp
new file mode 100644
index 00000000..b94718e2
--- /dev/null
+++ b/tests/test_bind_null_fuzzer.cpp
@@ -0,0 +1,76 @@
+/*
+ Copyright (c) 2020 Contributors as noted in the AUTHORS file
+
+ This file is part of libzmq, the ZeroMQ core engine in C++.
+
+ libzmq is free software; you can redistribute it and/or modify it under
+ the terms of the GNU Lesser General Public License (LGPL) as published
+ by the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ As a special exception, the Contributors give you permission to link
+ this library with independent modules to produce an executable,
+ regardless of the license terms of these independent modules, and to
+ copy and distribute the resulting executable under terms of your choice,
+ provided that you also meet, for each linked independent module, the
+ terms and conditions of the license of that module. An independent
+ module is a module which is not derived from or based on this library.
+ If you modify this library, you must extend this exception to your
+ version of the library.
+
+ libzmq is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see .
+*/
+
+#ifdef ZMQ_USE_FUZZING_ENGINE
+#include
+#endif
+
+#include "testutil.hpp"
+#include "testutil_unity.hpp"
+
+// Test that the ZMTP engine handles invalid handshake when binding
+// https://rfc.zeromq.org/spec/37/
+extern "C" int LLVMFuzzerTestOneInput (const uint8_t *data, size_t size)
+{
+ setup_test_context ();
+ char my_endpoint[MAX_SOCKET_STRING];
+ void *server = test_context_socket (ZMQ_PUB);
+ bind_loopback_ipv4 (server, my_endpoint, sizeof (my_endpoint));
+ fd_t client = connect_socket (my_endpoint);
+
+ for (ssize_t sent = 0; size > 0 && (sent != -1 || errno == EINTR);
+ size -= sent > 0 ? sent : 0, data += sent > 0 ? sent : 0)
+ sent = send (client, (const char *) data, size, MSG_NOSIGNAL);
+ msleep (250);
+
+ close (client);
+
+ test_context_socket_close_zero_linger (server);
+ teardown_test_context ();
+
+ return 0;
+}
+
+#ifndef ZMQ_USE_FUZZING_ENGINE
+void test_bind_null_fuzzer ()
+{
+ TEST_ASSERT_SUCCESS_ERRNO (
+ LLVMFuzzerTestOneInput (zmtp_greeting_null, sizeof (zmtp_greeting_null)));
+}
+
+int main (int argc, char **argv)
+{
+ setup_test_environment ();
+
+ UNITY_BEGIN ();
+ RUN_TEST (test_bind_null_fuzzer);
+
+ return UNITY_END ();
+}
+#endif
diff --git a/tests/test_connect_null_fuzzer.cpp b/tests/test_connect_null_fuzzer.cpp
new file mode 100644
index 00000000..e078b49f
--- /dev/null
+++ b/tests/test_connect_null_fuzzer.cpp
@@ -0,0 +1,80 @@
+/*
+ Copyright (c) 2020 Contributors as noted in the AUTHORS file
+
+ This file is part of libzmq, the ZeroMQ core engine in C++.
+
+ libzmq is free software; you can redistribute it and/or modify it under
+ the terms of the GNU Lesser General Public License (LGPL) as published
+ by the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ As a special exception, the Contributors give you permission to link
+ this library with independent modules to produce an executable,
+ regardless of the license terms of these independent modules, and to
+ copy and distribute the resulting executable under terms of your choice,
+ provided that you also meet, for each linked independent module, the
+ terms and conditions of the license of that module. An independent
+ module is a module which is not derived from or based on this library.
+ If you modify this library, you must extend this exception to your
+ version of the library.
+
+ libzmq is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see .
+*/
+
+#ifdef ZMQ_USE_FUZZING_ENGINE
+#include
+#endif
+
+#include "testutil.hpp"
+#include "testutil_unity.hpp"
+
+// Test that the ZMTP engine handles invalid handshake when connecting
+// https://rfc.zeromq.org/spec/37/
+extern "C" int LLVMFuzzerTestOneInput (const uint8_t *data, size_t size)
+{
+ setup_test_context ();
+ char my_endpoint[MAX_SOCKET_STRING];
+ fd_t server = bind_socket_resolve_port ("127.0.0.1", "0", my_endpoint);
+
+ void *client = test_context_socket (ZMQ_PUB);
+ TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (client, my_endpoint));
+
+ fd_t server_accept =
+ TEST_ASSERT_SUCCESS_RAW_ERRNO (accept (server, NULL, NULL));
+ for (ssize_t sent = 0; size > 0 && (sent != -1 || errno == EINTR);
+ size -= sent > 0 ? sent : 0, data += sent > 0 ? sent : 0)
+ sent = send (server_accept, (const char *) data, size, MSG_NOSIGNAL);
+ msleep (250);
+
+ close (server_accept);
+ close (server);
+
+ test_context_socket_close_zero_linger (client);
+ teardown_test_context ();
+
+ return 0;
+}
+
+#ifndef ZMQ_USE_FUZZING_ENGINE
+void test_connect_null_fuzzer ()
+{
+ TEST_ASSERT_SUCCESS_ERRNO (
+ LLVMFuzzerTestOneInput (zmtp_greeting_null, sizeof (zmtp_greeting_null)));
+}
+
+int main (int argc, char **argv)
+{
+ setup_test_environment ();
+
+ UNITY_BEGIN ();
+ RUN_TEST (test_connect_null_fuzzer);
+
+ return UNITY_END ();
+}
+#endif
diff --git a/tests/testutil.hpp b/tests/testutil.hpp
index 147584f4..00c23038 100644
--- a/tests/testutil.hpp
+++ b/tests/testutil.hpp
@@ -88,6 +88,10 @@ const uint8_t zmtp_ready_sub[27] = {
#undef NDEBUG
+#ifndef MSG_NOSIGNAL
+#define MSG_NOSIGNAL 0
+#endif
+
// duplicated from fd.hpp
#ifdef ZMQ_HAVE_WINDOWS
#ifndef NOMINMAX