afl-persistent: wrap udp with stdio. #349

tests-fuzz/Makefile.am

 AM_CPPFLAGS = \
 	-include $(top_builddir)/src/config.h \
-	-I$(top_srcdir)/src
-#	-I$(top_srcdir)/src/dnssec/lib
+	-I$(top_srcdir)/src \
+	-I$(top_srcdir)/src/dnssec/lib 
 
 LDADD = \
 	$(top_builddir)/src/libknot.la
 
 noinst_PROGRAMS = \
-	packet
+	packet \
+	knotd_stdio
+
+knotd_stdio_SOURCES = wrap/udp-handler.c wrap/server.c
+
+knotd_stdio_CPPFLAGS = $(AM_CPPFLAGS) $(liburcu_CFLAGS)
+knotd_stdio_LDADD = \
+	$(top_builddir)/src/knot/knotd-main.o \
+	$(top_builddir)/src/libknotd.la $(liburcu_LIBS)
+
+
+

tests-fuzz/wrap/server.c

+
+
+/*
+ * Wrap function server_reconfigure to initialize udp_master to stdin
+ */
+#define server_reconfigure _orig_server_reconfigure
+#include "knot/server/server.c"
+#undef server_reconfigure
+
+extern void udp_master_init_stdio(server_t *server);
+
+int server_reconfigure(conf_t *conf, void* data)
+{
+	log_info("AFL, Wrap server_reconfigure()");
+	int ret = _orig_server_reconfigure(conf, data);
+	udp_master_init_stdio(data);
+	return ret;
+}

tests-fuzz/wrap/udp-handler.c

+
+#include "knot/server/udp-handler.c"
+#include "knot/common/debug.h"
+
+/*
+ * Udp handler listen on stdin and send to stdout.
+ * To use this handler initialize it with udp_master_init_stdin.
+ */
+
+struct udp_stdin {
+	struct iovec iov[NBUFS];
+	uint8_t buf[NBUFS][KNOT_WIRE_MAX_PKTSIZE];
+	struct sockaddr_storage addr;
+};
+
+static void *udp_stdin_init(void)
+{
+	struct udp_stdin *rq = malloc(sizeof(struct udp_stdin));
+	memset(rq, 0, sizeof(struct udp_stdin));
+	for (unsigned i = 0; i < NBUFS; ++i) {
+		rq->iov[i].iov_base = rq->buf[i];
+		rq->iov[i].iov_len = KNOT_WIRE_MAX_PKTSIZE;
+	}
+	return rq;
+}
+
+static int udp_stdin_deinit(void *d)
+{
+	free(d);
+	return 0;
+}
+
+static int udp_stdin_recv(int fd, void *d)
+{
+	struct udp_stdin *rq = (struct udp_stdin *) d;
+	rq->iov[RX].iov_len = fread(rq->iov[RX].iov_base,
+	                            1, rq->iov[RX].iov_len, stdin);
+	return rq->iov[RX].iov_len;
+}
+
+static int udp_stdin_handle(udp_context_t *ctx, void *d)
+{
+	struct udp_stdin *rq = (struct udp_stdin *) d;
+	udp_handle(ctx, STDIN_FILENO, &rq->addr, &rq->iov[RX], &rq->iov[TX]);
+	return 0;
+}
+
+static int udp_stdin_send(void *d)
+{
+	struct udp_stdin *rq = (struct udp_stdin *) d;
+	fwrite(rq->iov[TX].iov_base, 1, rq->iov[TX].iov_len, stdout);
+	if (getenv("AFL_PERSISTENT")) {
+		raise(SIGSTOP);
+	} else {
+		exit(0);
+	}
+	return 0;
+}
+
+/*!
+ * \brief Initialize udp_handler with stdio
+ */
+void udp_master_init_stdio(server_t *server) {
+
+	log_info("AFL, UDP handler listen on stdin");
+
+	// register our dummy interface to server
+	iface_t * ifc = malloc(sizeof(iface_t));
+	ifc->fd[RX] = STDIN_FILENO;
+	ifc->fd[TX] = STDOUT_FILENO;
+	add_tail(&server->ifaces->l, (node_t *)ifc);
+
+	_udp_init = udp_stdin_init;
+	_udp_recv = udp_stdin_recv;
+	_udp_handle = udp_stdin_handle;
+	_udp_send = udp_stdin_send;
+	_udp_deinit = udp_stdin_deinit;
+}