upstream: remove this KEX fuzzer; it's awkward to use and doesn't play

nice with popular fuzzing drivers like libfuzzer. AFAIK nobody has used it
but me.

OpenBSD-Regress-ID: cad919522b3ce90c147c95abaf81b0492ac296c9

5 files changed, 1 insertions, 603 deletions

diff --git a/Makefile.in b/Makefile.in
index 76d3197f..e3cd296c 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -289,8 +289,6 @@ clean:	regressclean
 	rm -f regress/unittests/match/test_match$(EXEEXT)
 	rm -f regress/unittests/utf8/*.o
 	rm -f regress/unittests/utf8/test_utf8$(EXEEXT)
-	rm -f regress/misc/kexfuzz/*.o
-	rm -f regress/misc/kexfuzz/kexfuzz$(EXEEXT)
 	rm -f regress/misc/sk-dummy/*.o
 	rm -f regress/misc/sk-dummy/*.lo
 	rm -f regress/misc/sk-dummy/sk-dummy.so
@@ -324,8 +322,6 @@ distclean:	regressclean
 	rm -f regress/unittests/match/test_match
 	rm -f regress/unittests/utf8/*.o
 	rm -f regress/unittests/utf8/test_utf8
-	rm -f regress/misc/kexfuzz/*.o
-	rm -f regress/misc/kexfuzz/kexfuzz$(EXEEXT)
 	(cd openbsd-compat && $(MAKE) distclean)
 	if test -d pkg ; then \
 		rm -fr pkg ; \
@@ -497,7 +493,6 @@ regress-prep:
 	$(MKDIR_P) `pwd`/regress/unittests/kex
 	$(MKDIR_P) `pwd`/regress/unittests/match
 	$(MKDIR_P) `pwd`/regress/unittests/utf8
-	$(MKDIR_P) `pwd`/regress/misc/kexfuzz
 	$(MKDIR_P) `pwd`/regress/misc/sk-dummy
 	[ -f `pwd`/regress/Makefile ] || \
 	    ln -s `cd $(srcdir) && pwd`/regress/Makefile `pwd`/regress/Makefile
@@ -635,14 +630,6 @@ regress/unittests/utf8/test_utf8$(EXEEXT): \
 	    regress/unittests/test_helper/libtest_helper.a \
 	    -lssh -lopenbsd-compat -lssh -lopenbsd-compat $(LIBS)
 
-MISC_KEX_FUZZ_OBJS=\
-	regress/misc/kexfuzz/kexfuzz.o \
-	$(SKOBJS)
-
-regress/misc/kexfuzz/kexfuzz$(EXEEXT): ${MISC_KEX_FUZZ_OBJS} libssh.a
-	$(LD) -o $@ $(LDFLAGS) $(MISC_KEX_FUZZ_OBJS) \
-	    -lssh -lopenbsd-compat -lssh -lopenbsd-compat $(LIBS)
-
 # These all need to be compiled -fPIC, so they are treated differently.
 SK_DUMMY_OBJS=\
 	regress/misc/sk-dummy/sk-dummy.lo \
@@ -676,7 +663,6 @@ regress-unit-binaries: regress-prep $(REGRESSLIBS) \
 	regress/unittests/kex/test_kex$(EXEEXT) \
 	regress/unittests/match/test_match$(EXEEXT) \
 	regress/unittests/utf8/test_utf8$(EXEEXT) \
-	regress/misc/kexfuzz/kexfuzz$(EXEEXT)
 
 tests:	file-tests t-exec interop-tests unit
 	echo all tests passed
diff --git a/regress/misc/Makefile b/regress/misc/Makefile
index cf95f265..b9149f28 100644
--- a/regress/misc/Makefile
+++ b/regress/misc/Makefile
@@ -1,3 +1,3 @@
-SUBDIR=		kexfuzz sk-dummy
+SUBDIR=		sk-dummy
 
 .include <bsd.subdir.mk>
diff --git a/regress/misc/kexfuzz/Makefile b/regress/misc/kexfuzz/Makefile
deleted file mode 100644
index 18b70aa7..00000000
--- a/regress/misc/kexfuzz/Makefile
+++ /dev/null
@@ -1,101 +0,0 @@
-#	$OpenBSD: Makefile,v 1.10 2021/01/09 12:31:46 dtucker Exp $
-
-.include <bsd.own.mk>
-.include <bsd.obj.mk>
-
-# XXX detect from ssh binary?
-SSH1?=		no
-OPENSSL?=	yes
-
-PROG=	kexfuzz
-SRCS=	kexfuzz.c
-
-SSHREL=../../../../../usr.bin/ssh
-.PATH: ${.CURDIR}/${SSHREL}
-# From usr.bin/ssh
-SRCS+=sshbuf-getput-basic.c sshbuf-getput-crypto.c sshbuf-misc.c sshbuf.c
-SRCS+=atomicio.c sshkey.c authfile.c cipher.c log.c ssh-rsa.c ssh-dss.c
-SRCS+=ssh-ecdsa.c ssh-ed25519.c mac.c umac.c umac128.c hmac.c misc.c
-SRCS+=ssherr.c uidswap.c cleanup.c xmalloc.c match.c krl.c fatal.c
-SRCS+=addr.c addrmatch.c bitmap.c packet.c dispatch.c canohost.c ssh_api.c
-SRCS+=compat.c ed25519.c hash.c ge25519.c fe25519.c sc25519.c verify.c
-SRCS+=cipher-chachapoly.c chacha.c poly1305.c utf8.c
-SRCS+=sshbuf-io.c ssh-ecdsa-sk.c ssh-ed25519-sk.c msg.c ssh-sk-client.c
-
-SRCS+=	kex.c
-SRCS+=	dh.c
-SRCS+=	kexdh.c
-SRCS+=	kexecdh.c
-SRCS+=	kexgex.c
-SRCS+=	kexgexc.c
-SRCS+=	kexgexs.c
-SRCS+=	kexc25519.c
-SRCS+=	smult_curve25519_ref.c
-SRCS+=	kexgen.c
-SRCS+=	kexsntrup761x25519.c
-SRCS+=	sntrup761.c
-
-SRCS+=digest-openssl.c
-#SRCS+=digest-libc.c
-
-NOMAN=	1
-
-.if (${OPENSSL:L} == "yes")
-CFLAGS+=	-DWITH_OPENSSL
-.else
-# SSH v.1 requires OpenSSL.
-SSH1=		no
-.endif
-
-.if (${SSH1:L} == "yes")
-CFLAGS+=	-DWITH_SSH1
-.endif
-
-LDADD+= -lfido2 -lcbor -lusbhid
-DPADD+= ${LIBFIDO2} ${LIBCBOR} ${LIBUSBHID}
-
-# enable warnings
-WARNINGS=Yes
-
-DEBUG=-g
-CFLAGS+=	-fstack-protector-all
-CDIAGFLAGS=	-Wall
-CDIAGFLAGS+=	-Wextra
-CDIAGFLAGS+=	-Werror
-CDIAGFLAGS+=	-Wchar-subscripts
-CDIAGFLAGS+=	-Wcomment
-CDIAGFLAGS+=	-Wformat
-CDIAGFLAGS+=	-Wformat-security
-CDIAGFLAGS+=	-Wimplicit
-CDIAGFLAGS+=	-Winline
-CDIAGFLAGS+=	-Wmissing-declarations
-CDIAGFLAGS+=	-Wmissing-prototypes
-CDIAGFLAGS+=	-Wparentheses
-CDIAGFLAGS+=	-Wpointer-arith
-CDIAGFLAGS+=	-Wreturn-type
-CDIAGFLAGS+=	-Wshadow
-CDIAGFLAGS+=	-Wsign-compare
-CDIAGFLAGS+=	-Wstrict-aliasing
-CDIAGFLAGS+=	-Wstrict-prototypes
-CDIAGFLAGS+=	-Wswitch
-CDIAGFLAGS+=	-Wtrigraphs
-CDIAGFLAGS+=	-Wuninitialized
-CDIAGFLAGS+=	-Wunused
-CDIAGFLAGS+=	-Wno-unused-parameter
-.if ${COMPILER_VERSION:L} != "gcc3"
-CDIAGFLAGS+=	-Wold-style-definition
-.endif
-
-
-CFLAGS+=-I${.CURDIR}/${SSHREL}
-
-LDADD+= -lutil -lz
-DPADD+= ${LIBUTIL} ${LIBZ}
-
-.if (${OPENSSL:L} == "yes")
-LDADD+= -lcrypto
-DPADD+= ${LIBCRYPTO}
-.endif
-
-.include <bsd.prog.mk>
-
diff --git a/regress/misc/kexfuzz/README b/regress/misc/kexfuzz/README
deleted file mode 100644
index 504c26f3..00000000
--- a/regress/misc/kexfuzz/README
+++ /dev/null
@@ -1,34 +0,0 @@
-This is a harness to help with fuzzing KEX.
-
-To use it, you first set it to count packets in each direction:
-
-./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key -c
-S2C: 29
-C2S: 31
-
-Then get it to record a particular packet (in this case the 4th
-packet from client->server):
-
-./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key \
-    -d -D C2S -i 3 -f packet_3
-
-Fuzz the packet somehow:
-
-dd if=/dev/urandom of=packet_3 bs=32 count=1 # Just for example
-
-Then re-run the key exchange substituting the modified packet in
-its original sequence:
-
-./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key \
-    -r -D C2S -i 3 -f packet_3
-
-A comprehensive KEX fuzz run would fuzz every packet in both
-directions for each key exchange type and every hostkey type.
-This will take some time.
-
-Limitations: kexfuzz can't change the ordering of packets at
-present. It is limited to replacing individual packets with
-fuzzed variants with the same type. It really should allow
-insertion, deletion on replacement of packets too.
-
-$OpenBSD: README,v 1.3 2017/10/20 02:13:41 djm Exp $
diff --git a/regress/misc/kexfuzz/kexfuzz.c b/regress/misc/kexfuzz/kexfuzz.c
deleted file mode 100644
index 56697c91..00000000
--- a/regress/misc/kexfuzz/kexfuzz.c
+++ /dev/null
@@ -1,453 +0,0 @@
-/* 	$OpenBSD: kexfuzz.c,v 1.6 2020/01/26 00:09:50 djm Exp $ */
-/*
- * Fuzz harness for KEX code
- *
- * Placed in the public domain
- */
-
-#include "includes.h"
-
-#include <sys/types.h>
-#include <sys/param.h>
-#include <stdio.h>
-#ifdef HAVE_STDINT_H
-# include <stdint.h>
-#endif
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <fcntl.h>
-#ifdef HAVE_ERR_H
-# include <err.h>
-#endif
-
-#include "ssherr.h"
-#include "ssh_api.h"
-#include "sshbuf.h"
-#include "packet.h"
-#include "myproposal.h"
-#include "authfile.h"
-#include "log.h"
-
-void kex_tests(void);
-static int do_debug = 0;
-
-enum direction { S2C, C2S };
-
-struct hook_ctx {
-	struct ssh *client, *server, *server2;
-	int *c2s, *s2c;
-	int trigger_direction, packet_index;
-	const char *dump_path;
-	struct sshbuf *replace_data;
-};
-
-static int
-packet_hook(struct ssh *ssh, struct sshbuf *packet, u_char *typep, void *_ctx)
-{
-	struct hook_ctx *ctx = (struct hook_ctx *)_ctx;
-	int mydirection = ssh == ctx->client ? S2C : C2S;
-	int *packet_count = mydirection == S2C ? ctx->s2c : ctx->c2s;
-	FILE *dumpfile;
-	int r;
-
-	if (do_debug) {
-		printf("%s packet %d type %u:\n",
-		    mydirection == S2C ? "s2c" : "c2s",
-		    *packet_count, *typep);
-		sshbuf_dump(packet, stdout);
-	}
-	if (mydirection == ctx->trigger_direction &&
-	    ctx->packet_index == *packet_count) {
-		if (ctx->replace_data != NULL) {
-			sshbuf_reset(packet);
-			/* Type is first byte of packet */
-			if ((r = sshbuf_get_u8(ctx->replace_data,
-			    typep)) != 0 ||
-			    (r = sshbuf_putb(packet, ctx->replace_data)) != 0)
-				return r;
-			if (do_debug) {
-				printf("***** replaced packet type %u\n",
-				    *typep);
-				sshbuf_dump(packet, stdout);
-			}
-		} else if (ctx->dump_path != NULL) {
-			if ((dumpfile = fopen(ctx->dump_path, "w+")) == NULL)
-				err(1, "fopen %s", ctx->dump_path);
-			/* Write { type, packet } */
-			if (fwrite(typep, 1, 1, dumpfile) != 1)
-				err(1, "fwrite type %s", ctx->dump_path);
-			if (sshbuf_len(packet) != 0 &&
-			    fwrite(sshbuf_ptr(packet), sshbuf_len(packet),
-			    1, dumpfile) != 1)
-				err(1, "fwrite body %s", ctx->dump_path);
-			if (do_debug) {
-				printf("***** dumped packet type %u len %zu\n",
-				    *typep, sshbuf_len(packet));
-			}
-			fclose(dumpfile);
-			/* No point in continuing */
-			exit(0);
-		}
-	}
-	(*packet_count)++;
-	return 0;
-}
-
-static int
-do_send_and_receive(struct ssh *from, struct ssh *to)
-{
-	u_char type;
-	size_t len;
-	const u_char *buf;
-	int r;
-
-	for (;;) {
-		if ((r = ssh_packet_next(from, &type)) != 0) {
-			fprintf(stderr, "ssh_packet_next: %s\n", ssh_err(r));
-			return r;
-		}
-
-		if (type != 0)
-			return 0;
-		buf = ssh_output_ptr(from, &len);
-		if (len == 0)
-			return 0;
-		if ((r = ssh_input_append(to, buf, len)) != 0) {
-			debug("ssh_input_append: %s", ssh_err(r));
-			return r;
-		}
-		if ((r = ssh_output_consume(from, len)) != 0) {
-			debug("ssh_output_consume: %s", ssh_err(r));
-			return r;
-		}
-	}
-}
-
-/* Minimal test_helper.c scaffholding to make this standalone */
-const char *in_test = NULL;
-#define TEST_START(a)	\
-	do { \
-		in_test = (a); \
-		if (do_debug) \
-			fprintf(stderr, "test %s starting\n", in_test); \
-	} while (0)
-#define TEST_DONE()	\
-	do { \
-		if (do_debug) \
-			fprintf(stderr, "test %s done\n", \
-			    in_test ? in_test : "???"); \
-		in_test = NULL; \
-	} while(0)
-#define ASSERT_INT_EQ(a, b) \
-	do { \
-		if ((int)(a) != (int)(b)) { \
-			fprintf(stderr, "%s %s:%d " \
-			    "%s (%d) != expected %s (%d)\n", \
-			    in_test ? in_test : "(none)", \
-			    __func__, __LINE__, #a, (int)(a), #b, (int)(b)); \
-			exit(2); \
-		} \
-	} while (0)
-#define ASSERT_INT_GE(a, b) \
-	do { \
-		if ((int)(a) < (int)(b)) { \
-			fprintf(stderr, "%s %s:%d " \
-			    "%s (%d) < expected %s (%d)\n", \
-			    in_test ? in_test : "(none)", \
-			    __func__, __LINE__, #a, (int)(a), #b, (int)(b)); \
-			exit(2); \
-		} \
-	} while (0)
-#define ASSERT_PTR_NE(a, b) \
-	do { \
-		if ((a) == (b)) { \
-			fprintf(stderr, "%s %s:%d " \
-			    "%s (%p) != expected %s (%p)\n", \
-			    in_test ? in_test : "(none)", \
-			    __func__, __LINE__, #a, (a), #b, (b)); \
-			exit(2); \
-		} \
-	} while (0)
-
-
-static void
-run_kex(struct ssh *client, struct ssh *server)
-{
-	int r = 0;
-
-	while (!server->kex->done || !client->kex->done) {
-		if ((r = do_send_and_receive(server, client)) != 0) {
-			debug("do_send_and_receive S2C: %s", ssh_err(r));
-			break;
-		}
-		if ((r = do_send_and_receive(client, server)) != 0) {
-			debug("do_send_and_receive C2S: %s", ssh_err(r));
-			break;
-		}
-	}
-	if (do_debug)
-		printf("done: %s\n", ssh_err(r));
-	ASSERT_INT_EQ(r, 0);
-	ASSERT_INT_EQ(server->kex->done, 1);
-	ASSERT_INT_EQ(client->kex->done, 1);
-}
-
-static void
-do_kex_with_key(const char *kex, struct sshkey *prvkey, int *c2s, int *s2c,
-    int direction, int packet_index,
-    const char *dump_path, struct sshbuf *replace_data)
-{
-	struct ssh *client = NULL, *server = NULL, *server2 = NULL;
-	struct sshkey *pubkey = NULL;
-	struct sshbuf *state;
-	struct kex_params kex_params;
-	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
-	char *keyname = NULL;
-	struct hook_ctx hook_ctx;
-
-	TEST_START("sshkey_from_private");
-	ASSERT_INT_EQ(sshkey_from_private(prvkey, &pubkey), 0);
-	TEST_DONE();
-
-	TEST_START("ssh_init");
-	memcpy(kex_params.proposal, myproposal, sizeof(myproposal));
-	if (kex != NULL)
-		kex_params.proposal[PROPOSAL_KEX_ALGS] = strdup(kex);
-	keyname = strdup(sshkey_ssh_name(prvkey));
-	ASSERT_PTR_NE(keyname, NULL);
-	kex_params.proposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = keyname;
-	ASSERT_INT_EQ(ssh_init(&client, 0, &kex_params), 0);
-	ASSERT_INT_EQ(ssh_init(&server, 1, &kex_params), 0);
-	ASSERT_INT_EQ(ssh_init(&server2, 1, NULL), 0);
-	ASSERT_PTR_NE(client, NULL);
-	ASSERT_PTR_NE(server, NULL);
-	ASSERT_PTR_NE(server2, NULL);
-	TEST_DONE();
-
-	hook_ctx.c2s = c2s;
-	hook_ctx.s2c = s2c;
-	hook_ctx.trigger_direction = direction;
-	hook_ctx.packet_index = packet_index;
-	hook_ctx.dump_path = dump_path;
-	hook_ctx.replace_data = replace_data;
-	hook_ctx.client = client;
-	hook_ctx.server = server;
-	hook_ctx.server2 = server2;
-	ssh_packet_set_input_hook(client, packet_hook, &hook_ctx);
-	ssh_packet_set_input_hook(server, packet_hook, &hook_ctx);
-	ssh_packet_set_input_hook(server2, packet_hook, &hook_ctx);
-
-	TEST_START("ssh_add_hostkey");
-	ASSERT_INT_EQ(ssh_add_hostkey(server, prvkey), 0);
-	ASSERT_INT_EQ(ssh_add_hostkey(client, pubkey), 0);
-	TEST_DONE();
-
-	TEST_START("kex");
-	run_kex(client, server);
-	TEST_DONE();
-
-	TEST_START("rekeying client");
-	ASSERT_INT_EQ(kex_send_kexinit(client), 0);
-	run_kex(client, server);
-	TEST_DONE();
-
-	TEST_START("rekeying server");
-	ASSERT_INT_EQ(kex_send_kexinit(server), 0);
-	run_kex(client, server);
-	TEST_DONE();
-
-	TEST_START("ssh_packet_get_state");
-	state = sshbuf_new();
-	ASSERT_PTR_NE(state, NULL);
-	ASSERT_INT_EQ(ssh_packet_get_state(server, state), 0);
-	ASSERT_INT_GE(sshbuf_len(state), 1);
-	TEST_DONE();
-
-	TEST_START("ssh_packet_set_state");
-	ASSERT_INT_EQ(ssh_add_hostkey(server2, prvkey), 0);
-	kex_free(server2->kex);	/* XXX or should ssh_packet_set_state()? */
-	ASSERT_INT_EQ(ssh_packet_set_state(server2, state), 0);
-	ASSERT_INT_EQ(sshbuf_len(state), 0);
-	sshbuf_free(state);
-	ASSERT_PTR_NE(server2->kex, NULL);
-	/* XXX we need to set the callbacks */
-#ifdef WITH_OPENSSL
-	server2->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server;
-	server2->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server;
-	server2->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server;
-	server2->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server;
-	server2->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server;
-	server2->kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
-	server2->kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
-# ifdef OPENSSL_HAS_ECC
-	server2->kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
-# endif
-#endif
-	server2->kex->kex[KEX_C25519_SHA256] = kex_gen_server;
-	server2->kex->load_host_public_key = server->kex->load_host_public_key;
-	server2->kex->load_host_private_key = server->kex->load_host_private_key;
-	server2->kex->sign = server->kex->sign;
-	TEST_DONE();
-
-	TEST_START("rekeying server2");
-	ASSERT_INT_EQ(kex_send_kexinit(server2), 0);
-	run_kex(client, server2);
-	ASSERT_INT_EQ(kex_send_kexinit(client), 0);
-	run_kex(client, server2);
-	TEST_DONE();
-
-	TEST_START("cleanup");
-	sshkey_free(pubkey);
-	ssh_free(client);
-	ssh_free(server);
-	ssh_free(server2);
-	free(keyname);
-	TEST_DONE();
-}
-
-static void
-usage(void)
-{
-	fprintf(stderr,
-	    "Usage: kexfuzz [-hcdrv] [-D direction] [-f data_file]\n"
-	    "               [-K kex_alg] [-k private_key] [-i packet_index]\n"
-	    "\n"
-	    "Options:\n"
-	    "    -h               Display this help\n"
-	    "    -c               Count packets sent during KEX\n"
-	    "    -d               Dump mode: record KEX packet to data file\n"
-	    "    -r               Replace mode: replace packet with data file\n"
-	    "    -v               Turn on verbose logging\n"
-	    "    -D S2C|C2S       Packet direction for replacement or dump\n"
-	    "    -f data_file     Path to data file for replacement or dump\n"
-	    "    -K kex_alg       Name of KEX algorithm to test (see below)\n"
-	    "    -k private_key   Path to private key file\n"
-	    "    -i packet_index  Index of packet to replace or dump (from 0)\n"
-	    "\n"
-	    "Available KEX algorithms: %s\n", kex_alg_list(' '));
-}
-
-static void
-badusage(const char *bad)
-{
-	fprintf(stderr, "Invalid options\n");
-	fprintf(stderr, "%s\n", bad);
-	usage();
-	exit(1);
-}
-
-int
-main(int argc, char **argv)
-{
-	int ch, fd, r;
-	int count_flag = 0, dump_flag = 0, replace_flag = 0;
-	int packet_index = -1, direction = -1;
-	int s2c = 0, c2s = 0; /* packet counts */
-	const char *kex = NULL, *kpath = NULL, *data_path = NULL;
-	struct sshkey *key = NULL;
-	struct sshbuf *replace_data = NULL;
-
-	setvbuf(stdout, NULL, _IONBF, 0);
-	while ((ch = getopt(argc, argv, "hcdrvD:f:K:k:i:")) != -1) {
-		switch (ch) {
-		case 'h':
-			usage();
-			return 0;
-		case 'c':
-			count_flag = 1;
-			break;
-		case 'd':
-			dump_flag = 1;
-			break;
-		case 'r':
-			replace_flag = 1;
-			break;
-		case 'v':
-			do_debug = 1;
-			break;
-
-		case 'D':
-			if (strcasecmp(optarg, "s2c") == 0)
-				direction = S2C;
-			else if (strcasecmp(optarg, "c2s") == 0)
-				direction = C2S;
-			else
-				badusage("Invalid direction (-D)");
-			break;
-		case 'f':
-			data_path = optarg;
-			break;
-		case 'K':
-			kex = optarg;
-			break;
-		case 'k':
-			kpath = optarg;
-			break;
-		case 'i':
-			packet_index = atoi(optarg);
-			if (packet_index < 0)
-				badusage("Invalid packet index");
-			break;
-		default:
-			badusage("unsupported flag");
-		}
-	}
-	argc -= optind;
-	argv += optind;
-
-	log_init(argv[0], do_debug ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO,
-	    SYSLOG_FACILITY_USER, 1);
-
-	/* Must select a single mode */
-	if ((count_flag + dump_flag + replace_flag) != 1)
-		badusage("Must select one mode: -c, -d or -r");
-	/* KEX type is mandatory */
-	if (kex == NULL || !kex_names_valid(kex) || strchr(kex, ',') != NULL)
-		badusage("Missing or invalid kex type (-K flag)");
-	/* Valid key is mandatory */
-	if (kpath == NULL)
-		badusage("Missing private key (-k flag)");
-	if ((fd = open(kpath, O_RDONLY)) == -1)
-		err(1, "open %s", kpath);
-	if ((r = sshkey_load_private_type_fd(fd, KEY_UNSPEC, NULL,
-	    &key, NULL)) != 0)
-		errx(1, "Unable to load key %s: %s", kpath, ssh_err(r));
-	close(fd);
-	/* XXX check that it is a private key */
-	/* XXX support certificates */
-	if (key == NULL || key->type == KEY_UNSPEC)
-		badusage("Invalid key file (-k flag)");
-
-	/* Replace (fuzz) mode */
-	if (replace_flag) {
-		if (packet_index == -1 || direction == -1 || data_path == NULL)
-			badusage("Replace (-r) mode must specify direction "
-			    "(-D) packet index (-i) and data path (-f)");
-		if ((r = sshbuf_load_file(data_path, &replace_data)) != 0)
-			errx(1, "read %s: %s", data_path, ssh_err(r));
-	}
-
-	/* Dump mode */
-	if (dump_flag) {
-		if (packet_index == -1 || direction == -1 || data_path == NULL)
-			badusage("Dump (-d) mode must specify direction "
-			    "(-D), packet index (-i) and data path (-f)");
-	}
-
-	/* Count mode needs no further flags */
-
-	do_kex_with_key(kex, key, &c2s, &s2c,
-	    direction, packet_index,
-	    dump_flag ? data_path : NULL,
-	    replace_flag ? replace_data : NULL);
-	sshkey_free(key);
-	sshbuf_free(replace_data);
-
-	if (count_flag) {
-		printf("S2C: %d\n", s2c);
-		printf("C2S: %d\n", c2s);
-	}
-
-	return 0;
-}