fuzxy

This is the initial push of a fuzzing proxy we will use for testing lws.

Run libwebsockets-test-fuzxy and the test server if it's local.

Then run the test client with

http_proxy=localhost:8880 libwebsockets-test-client localhost (or whatever)

Right now he only fuzzes one thing but he is operational as a proxy.

CMakeLists.txt

@@ -786,6 +786,13 @@ if (NOT LWS_WITHOUT_TESTAPPS)
 				"test-server/test-server-dumb-increment.c"
 				"test-server/test-server-mirror.c"
 				"test-server/test-server-echogen.c")
+			if (UNIX)
+				create_test_app(test-fuzxy "test-server/fuzxy.c"
+					""
+					""
+					""
+					"")
+			endif()
 			if (UNIX AND NOT ((CMAKE_C_COMPILER_ID MATCHES "Clang") OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang")))
 				create_test_app(test-server-pthreads
 					"test-server/test-server-pthreads.c"

test-server/fuzxy.c

@@ -0,0 +1,683 @@
+/*
+ * fuzzing proxy - network-level fuzzing injection proxy
+ *
+ * Copyright (C) 2016 Andy Green <andy@warmcat.com>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation:
+ *  version 2.1 of the License.
+ *
+ *  This library 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 library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *  MA  02110-1301  USA
+ *
+ *
+ * fuzxy is designed to go on the client path
+ *
+ * [ client <-> fuzxy ] <-> server
+ *
+ * you can arrange that with, eg,
+ *
+ *  http_proxy=localhost:8880
+ *
+ * env var before starting the client.
+ *
+ * Even though he is on the client side, he is able to see and change traffic
+ * in both directions, and so fuzz both the client and the server.
+ */
+
+#if defined(_WIN32) && defined(EXTERNAL_POLL)
+#define WINVER 0x0600
+#define _WIN32_WINNT 0x0600
+#define poll(fdArray, fds, timeout)  WSAPoll((LPWSAPOLLFD)(fdArray), (ULONG)(fds), (INT)(timeout))
+#endif
+
+#include "lws_config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <errno.h>
+#include "../lib/libwebsockets.h"
+
+#ifdef _WIN32
+#include <io.h>
+#include "gettimeofday.h"
+#else
+#include <syslog.h>
+#include <sys/time.h>
+#include <unistd.h>
+#endif
+
+
+enum types {
+	FZY_S_DEAD		= 0,
+	FZY_S_LISTENING		= 1,
+	FZY_S_ACCEPTED		= 2,
+	FZY_S_PROXIED		= 3,
+	FZY_S_ONWARD		= 4,
+};
+
+enum proxy_parser_states {
+	FZY_PP_CONNECT		= 0,
+	FZY_PP_ADDRESS		= 1,
+	FZY_PP_PORT		= 2,
+	FZY_PP_CRLFS		= 3,
+};
+
+enum fuzzer_parser_states {
+	FZY_FP_SEARCH		= 0,
+	FZY_FP_SEARCH2		= 1,
+	FZY_FP_INJECT		= 2,
+	FZY_FP_PENDING		= 3,
+};
+
+struct ring {
+	char buf[4096];
+	int head;
+	int tail;
+};
+
+struct state {
+	enum types type;
+	enum proxy_parser_states pp;
+	int ppc;
+
+	struct ring in;
+
+	char address[256];
+	int port;
+
+	enum fuzzer_parser_states fp;
+	int fuzc;
+	int pending;
+
+	int twin; /* must be fixed up when arrays lose guys */
+	unsigned int outbound:1; /* from local -> remote */
+};
+
+
+int force_exit = 0;
+
+static const int ring_size(struct ring *r)
+{
+	return sizeof(r->buf);
+}
+static const int ring_used(struct ring *r)
+{
+	return (r->head - r->tail) & (ring_size(r) - 1);
+}
+static const int ring_free(struct ring *r)
+{
+	return (ring_size(r) - 1) - ring_used(r);
+}
+static const int ring_get_one(struct ring *r)
+{
+	int n = r->buf[r->tail] & 255;
+
+	if (r->tail == r->head)
+		return -1;
+
+	r->tail++;
+	if (r->tail == ring_size(r))
+		r->tail = 0;
+
+	return n;
+}
+
+void sighandler(int sig)
+{
+	force_exit = 1;
+}
+
+static struct option options[] = {
+	{ "help",	no_argument,		NULL, 'h' },
+	{ "debug",	required_argument,	NULL, 'd' },
+	{ "port",	required_argument,	NULL, 'p' },
+	{ "ssl",	no_argument,		NULL, 's' },
+	{ "allow-non-ssl",	no_argument,	NULL, 'a' },
+	{ "interface",  required_argument,	NULL, 'i' },
+	{ "closetest",  no_argument,		NULL, 'c' },
+	{ "libev",  no_argument,		NULL, 'e' },
+#ifndef LWS_NO_DAEMONIZE
+	{ "daemonize", 	no_argument,		NULL, 'D' },
+#endif
+	{ "resource_path", required_argument,	NULL, 'r' },
+	{ NULL, 0, 0, 0 }
+};
+
+static struct pollfd pfd[128];
+static struct state state[128];
+static int pfds = 0;
+
+static void close_and_remove_fd(int index)
+{
+	int n;
+
+	lwsl_notice("%s: closing index %d\n", __func__, index);
+	close(pfd[index].fd);
+	pfd[index].fd = -1;
+
+	n = state[index].twin;
+	if (n) {
+		assert(state[n].twin == index);
+	}
+	state[index].type = FZY_S_DEAD;
+
+	if (index == pfds - 1) {
+		if (state[index].twin)
+			state[state[index].twin].twin = 0;
+		state[index].twin = 0;
+		goto bail;
+	}
+
+	/* swap the end guy into the deleted guy and trim back one */
+
+	if (state[pfds - 1].twin) {
+		state[state[pfds - 1].twin].twin = index;
+		if (n && n == pfds - 1)
+			n = index;
+	}
+
+	/* swap the last guy into dead guy's place and trim by one */
+	pfd[index] = pfd[pfds - 1];
+	state[index] = state[pfds - 1];
+
+	if (n) {
+		pfds--;
+		state[n].twin = 0;
+		close_and_remove_fd(n);
+		return;
+	}
+
+bail:
+	pfds--;
+}
+
+static void construct_state(int n, enum types s, int flags)
+{
+	memset(&state[n], 0, sizeof state[n]);
+	state[n].type = s;
+	pfd[n].events = flags | POLLHUP;
+}
+
+static int
+fuzxy_listen(const char *interface_name, int port, int *sockfd)
+{
+	struct sockaddr_in serv_addr4;
+	socklen_t len = sizeof(struct sockaddr);
+	struct sockaddr_in sin;
+	int n, opt = 1;
+
+	*sockfd = socket(AF_INET, SOCK_STREAM, 0);
+
+	if (*sockfd == -1) {
+		lwsl_err("ERROR opening socket\n");
+		goto bail1;
+	}
+
+	if (setsockopt(*sockfd, SOL_SOCKET, SO_REUSEADDR,
+		       (const void *)&opt, sizeof(opt)) < 0) {
+		lwsl_err("unable to set listen socket options\n");
+		goto bail2;
+	}
+
+	bzero((char *) &serv_addr4, sizeof(serv_addr4));
+	serv_addr4.sin_addr.s_addr = INADDR_ANY;
+	serv_addr4.sin_family = AF_INET;
+
+	if (interface_name[0] &&
+	    lws_interface_to_sa(0, interface_name, (struct sockaddr_in *)
+			        (struct sockaddr *)&serv_addr4,
+				sizeof(serv_addr4)) < 0) {
+		lwsl_err("Unable to find interface %s\n", interface_name);
+		goto bail2;
+	}
+
+	serv_addr4.sin_port = htons(port);
+
+	n = bind(*sockfd, (struct sockaddr *)&serv_addr4,
+				sizeof(serv_addr4));
+	if (n < 0) {
+		lwsl_err("ERROR on binding to port %d (%d %d)\n",
+			 port, n, errno);
+		goto bail2;
+	}
+
+	if (getsockname(*sockfd, (struct sockaddr *)&sin, &len) == -1)
+		lwsl_warn("getsockname: %s\n", strerror(errno));
+	else
+		port = ntohs(sin.sin_port);
+
+	listen(*sockfd, SOMAXCONN);
+
+	return 0;
+bail2:
+	close(*sockfd);
+bail1:
+	return -1;
+}
+
+struct fuzxy_rule {
+	const char *s[3];
+	int len[3];
+	int inject_len;
+};
+
+struct fuzxy_rule r = {
+		{ "Host:", "\x0d", " \x0d" },
+		{ 5, 1, 2 },
+		65536
+};
+
+static int fuzz(int n, char *out, int len)
+{
+	struct state *s = &state[n];
+	int m = 0;
+	int c;
+
+	while (m < len) {
+		switch (s->fp) {
+		case FZY_FP_SEARCH:
+			c = ring_get_one(&state[s->twin].in);
+			if (c < 0)
+				return m;
+			if (c == r.s[0][s->fuzc++]) {
+				if (s->fuzc == r.len[0]) {
+					s->fuzc = 0;
+					s->fp = FZY_FP_SEARCH2;
+				}
+			} else
+				s->fuzc = 0;
+			out[m++] = c;
+			break;
+
+		case FZY_FP_SEARCH2:
+			c = ring_get_one(&state[s->twin].in);
+			if (c < 0)
+				return m;
+			if (c == r.s[1][s->fuzc++]) {
+				if (s->fuzc == r.len[1]) {
+					lwsl_notice("+++++++fuzzer hit...\n");
+					s->fuzc = 0;
+					s->fp = FZY_FP_INJECT;
+					s->pending = c;
+					goto inject;
+				}
+			} else
+				s->fuzc = 0;
+			out[m++] = c;
+			break;
+		case FZY_FP_INJECT:
+inject:
+			out[m++] = r.s[2][s->fuzc++ % r.len[2]];
+			if (s->fuzc == r.inject_len)
+				s->fp = FZY_FP_PENDING;
+			break;
+
+		case FZY_FP_PENDING:
+			out[m++] = s->pending;
+			s->fp = FZY_FP_SEARCH;
+			s->fuzc = 0;
+			break;
+		}
+	}
+
+	return m;
+}
+
+static int
+handle_accept(int n)
+{
+	struct addrinfo ai, *res, *result;
+	struct sockaddr_in serv_addr4;
+	struct state *s = &state[n];
+	void *p = NULL;
+	int m, sockfd;
+
+	while (1) {
+		m = ring_get_one(&s->in);
+		if (m < 0)
+			return 0;
+
+		switch (s->pp) {
+		case FZY_PP_CONNECT:
+			if (m != "CONNECT "[s->ppc++]) {
+				lwsl_notice("failed CONNECT match\n");
+				return 1;
+			}
+			if (s->ppc == 8) {
+				s->pp = FZY_PP_ADDRESS;
+				s->ppc = 0;
+			}
+			break;
+		case FZY_PP_ADDRESS:
+			if (m == ':') {
+				s->address[s->ppc++] = '\0';
+				s->pp = FZY_PP_PORT;
+				s->ppc = 0;
+				break;
+			}
+			if (m == ' ') {
+				s->address[s->ppc++] = '\0';
+				s->pp = FZY_PP_CRLFS;
+				s->ppc = 0;
+				break;
+			}
+
+
+			s->address[s->ppc++] = m;
+			if (s->ppc == sizeof(s->address)) {
+				lwsl_notice("Failed on address length\n");
+				return 1;
+			}
+			break;
+		case FZY_PP_PORT:
+			if (m == ' ') {
+				s->pp = FZY_PP_CRLFS;
+				s->ppc = 0;
+				break;
+			}
+			if (m >= '0' && m <= '9') {
+				s->port *= 10;
+				s->port += m - '0';
+				break;
+			}
+			return 1;
+
+		case FZY_PP_CRLFS:
+			if (m != "\x0d\x0a\x0d\x0a"[s->ppc++])
+				s->ppc = 0;
+			if (s->ppc != 4)
+				break;
+			s->type = FZY_S_PROXIED;
+
+			memset (&ai, 0, sizeof ai);
+			ai.ai_family = PF_UNSPEC;
+			ai.ai_socktype = SOCK_STREAM;
+			ai.ai_flags = AI_CANONNAME;
+
+			if (getaddrinfo(s->address, NULL, &ai, &result)) {
+				lwsl_notice("failed to lookup %s\n",
+					    s->address);
+				return 1;
+			}
+
+			res = result;
+			while (!p && res) {
+				switch (res->ai_family) {
+				case AF_INET:
+					p = &((struct sockaddr_in *)res->
+					      ai_addr)->sin_addr;
+					break;
+				}
+
+				res = res->ai_next;
+			}
+
+			if (!p) {
+				lwsl_notice("Failed to get address result %s\n",
+					    s->address);
+				freeaddrinfo(result);
+				return 1;
+			}
+
+			serv_addr4.sin_family = AF_INET;
+			serv_addr4.sin_addr = *((struct in_addr *)p);
+			serv_addr4.sin_port = htons(s->port);
+			bzero(&serv_addr4.sin_zero, 8);
+			freeaddrinfo(result);
+
+			lwsl_err("Conn %d req '%s' port %d\n", n,
+				 s->address, s->port);
+			/* we need to open the associated onward connection */
+			sockfd = socket(AF_INET, SOCK_STREAM, 0);
+
+			if (connect(sockfd, (struct sockaddr *)&serv_addr4,
+				    sizeof(struct sockaddr)) == -1 ||
+			    errno == EISCONN) {
+				lwsl_err("proxied onward connection failed\n");
+				return 1;
+			}
+			s->twin = pfds;
+			construct_state(pfds, FZY_S_ONWARD,
+					POLLOUT | POLLIN | POLLERR);
+			state[pfds].twin = n;
+			lwsl_notice("binding conns %d and %d\n", n, pfds);
+			state[pfds].outbound = s->outbound;
+			state[pfds].ppc = 0;
+			pfd[pfds++].fd = sockfd;
+
+			lwsl_notice("onward connection in progress\n");
+			if (ring_used(&s->in))
+				pfd[s->twin].events |= POLLOUT;
+			if (write(pfd[n].fd,
+				  "HTTP/1.0 200 \x0d\x0a\x0d\x0a", 17) < 17)
+				return 1;
+		}
+	}
+
+	return 0;
+}
+
+static void sigpipe_handler(int x)
+{
+}
+
+int
+main(int argc, char **argv)
+{
+	char interface_name[128] = "", interface_name_local[128] = "lo";
+	int port_local = 8880, accept_fd;
+	struct sockaddr_in cli_addr;
+	int debug_level = 7;
+	socklen_t clilen;
+	struct state *s;
+	char out[4096];
+	int opts = 0;
+	int n = 0, m;
+
+#ifndef _WIN32
+	int syslog_options = LOG_PID | LOG_PERROR;
+#endif
+#ifndef LWS_NO_DAEMONIZE
+ 	int daemonize = 0;
+#endif
+	signal(SIGPIPE, sigpipe_handler);
+
+	while (n >= 0) {
+		n = getopt_long(argc, argv, "eci:hsap:d:Dr:", options, NULL);
+		if (n < 0)
+			continue;
+		switch (n) {
+		case 'e':
+			opts |= LWS_SERVER_OPTION_LIBEV;
+			break;
+#ifndef LWS_NO_DAEMONIZE
+		case 'D':
+			daemonize = 1;
+			#ifndef _WIN32
+			syslog_options &= ~LOG_PERROR;
+			#endif
+			break;
+#endif
+		case 'd':
+			debug_level = atoi(optarg);
+			break;
+		case 'p':
+			port_local = atoi(optarg);
+			break;
+		case 'i':
+			strncpy(interface_name, optarg, sizeof interface_name);
+			interface_name[(sizeof interface_name) - 1] = '\0';
+			break;
+		case 'h':
+			fprintf(stderr, "Usage: libwebsockets-test-fuzxy "
+					"[--port=<p>] [--ssl] "
+					"[-d <log bitfield>] "
+					"[--resource_path <path>]\n");
+			exit(1);
+		}
+	}
+
+#if !defined(LWS_NO_DAEMONIZE) && !defined(WIN32)
+	/*
+	 * normally lock path would be /var/lock/lwsts or similar, to
+	 * simplify getting started without having to take care about
+	 * permissions or running as root, set to /tmp/.lwsts-lock
+	 */
+	if (daemonize && lws_daemonize("/tmp/.lwsts-lock")) {
+		fprintf(stderr, "Failed to daemonize\n");
+		return 1;
+	}
+#endif
+
+	signal(SIGINT, sighandler);
+
+#ifndef _WIN32
+	/* we will only try to log things according to our debug_level */
+	setlogmask(LOG_UPTO (LOG_DEBUG));
+	openlog("fuzxy", syslog_options, LOG_DAEMON);
+#endif
+
+	/* tell the library what debug level to emit and to send it to syslog */
+	lws_set_log_level(debug_level, lwsl_emit_syslog);
+
+	lwsl_notice("%s\n(C) Copyright 2016 Andy Green <andy@warmcat.com> - "
+		    "licensed under LGPL2.1\n", argv[0]);
+
+	/* listen on local side */
+
+	if (fuzxy_listen(interface_name, port_local, &pfd[pfds].fd)) {
+		lwsl_err("Failed to listen on local side\n");
+		goto bail1;
+	}
+	construct_state(pfds, FZY_S_LISTENING, POLLIN | POLLERR);
+	pfds++;
+
+	lwsl_notice("Local side listening on %s:%u\n",
+		    interface_name_local, port_local);
+
+	while (!force_exit) {
+
+		m = poll(pfd, pfds, 50);
+		if (m < 0)
+			continue;
+		for (n = 0; n < pfds; n++) {
+			s = &state[n];
+			if (s->type == FZY_S_LISTENING &&
+			    (pfd[n].revents & POLLIN)) {
+				/* first do the accept entry */
+
+				clilen = sizeof(cli_addr);
+				accept_fd = accept(pfd[0].fd,
+					 (struct sockaddr *)&cli_addr, &clilen);
+				if (accept_fd < 0) {
+					if (errno == EAGAIN ||
+					    errno == EWOULDBLOCK)
+						continue;
+
+					lwsl_warn("ERROR on accept: %s\n",
+						  strerror(errno));
+					continue;
+				}
+				construct_state(pfds, FZY_S_ACCEPTED,
+						POLLIN | POLLERR);
+				state[pfds].outbound = n == 0;
+				state[pfds].pp = FZY_PP_CONNECT;
+				state[pfds].ppc = 0;
+				pfd[pfds++].fd = accept_fd;
+				lwsl_notice("new connect accepted\n");
+				continue;
+			}
+			if (pfd[n].revents & POLLIN) {
+				assert(ring_free(&s->in));
+				m = (ring_size(&s->in) - 1) -
+				    s->in.head;
+				if (s->in.head == ring_size(&s->in) - 1 &&
+				    s->in.tail)
+					m = 1;
+				m = read(pfd[n].fd, s->in.buf + s->in.head, m);
+//				lwsl_notice("read %d\n", m);
+				if (m <= 0)
+					goto drop;
+				s->in.head += m;
+				if (s->in.head == ring_size(&s->in))
+					s->in.head = 0;
+
+				switch (s->type) {
+				case FZY_S_ACCEPTED: /* parse proxy CONNECT */
+					if (handle_accept(n))
+						goto drop;
+					break;
+				case FZY_S_PROXIED:
+				case FZY_S_ONWARD:
+					if (ring_used(&s->in))
+						pfd[s->twin].events |= POLLOUT;
+					break;
+				default:
+					assert(0);
+					break;
+				}
+				if (s->in.head == s->in.tail) {
+					s->in.head = s->in.tail = 0;
+					pfd[n].events |= POLLIN;
+				}
+				if (!ring_free(&s->in))
+					pfd[n].events &= ~POLLIN;
+			}
+			if (pfd[n].revents & POLLOUT) {
+				switch (s->type) {
+				case FZY_S_PROXIED:
+				case FZY_S_ONWARD:
+					/*
+					 * draw down enough of the partner's
+					 * in ring to either exhaust it
+ 					 * or fill an output buffer
+ 					 */
+					m = fuzz(n, out, sizeof(out));
+					if (m) {
+						m = write(pfd[n].fd, out, m);
+						if (m <= 0)
+							goto drop;
+					} else
+						pfd[n].events &= ~POLLOUT;
+
+					if (ring_free(&state[s->twin].in))
+						pfd[s->twin].events |= POLLIN;
+
+					break;
+				default:
+					break;
+				}
+			}
+
+			continue;
+drop:
+			close_and_remove_fd(n);
+			n--; /* redo this slot */
+		}
+	}
+
+bail1:
+	lwsl_notice("%s exited cleanly\n", argv[0]);
+
+#ifndef _WIN32
+	closelog();
+#endif
+
+	return 0;
+}
+