tls-shake

client-hello.c (2686B)

#include "debug.h"            /* debug_printf */
#include "tls-parameters-4.h" /* ciphers */

#include <err.h>
#include <errno.h> // errno
#include <netdb.h> // getaddrinfo()
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h> /* arc4random_buf() */
#include <string.h> /* memset(), strlcpy(), strlcat() */
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h> /* close() */

static int SSL_TLS_versions[] = {
    0x0200, /* 2.0: SSLv2 */
    0x0300, /* 3.0: SSLv3 */
    0x0301, /* 3.1: TLSv1.0 */
    0x0302, /* 3.2: TLSv1.1 */
    0x0303, /* 3.3: TLSv1.2 */
};

static void usage(char *command)
{
	printf("Usage: %s <host> [port]\n", command);
	printf("Default port: 443\n");
	exit(0);
}

int main(int argc, char *argv[])
{
	size_t send_result;
	char *handshake, *tls_packet, *client_hello;
	char *s_port = "1337", random_bytes[32];

	if(argc < 2 || argc > 3) usage(argv[0]);

	/* START network connection, copied from manpages of getaddrinfo(3) from OpenBSD and GNU */
	struct addrinfo hints, *result, *rp;
	int error      = 0;
	int save_errno = errno;
	int s          = 0;

	memset(&hints, 0, sizeof(hints));
	hints.ai_family   = AF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_flags    = 0;
	hints.ai_protocol = 0;

	error = getaddrinfo(argv[1], s_port, &hints, &result);
	if(error != 0) errx(1, "getaddrinfo: %s", gai_strerror(error));

	for(rp = result; rp != NULL; rp = rp->ai_next)
	{
		s = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);

		if(connect(s, rp->ai_addr, rp->ai_addrlen) != -1)
		{
			break;
		}
		else
		{
			save_errno = errno;
		}

		close(s);
	}

	if((s == -1) | (rp == NULL))
	{
		perror(strerror(save_errno));
		exit(EXIT_FAILURE);
	}

	freeaddrinfo(result);

	/* DONE network connection */
	arc4random_buf(random_bytes, sizeof(random_bytes));

	tls_packet = (uint16_t)'\x01'; /* client hello: 0x01 */

	strlcpy(client_hello, (uint32_t)0x0303, 4); /* SSL version max */
	strlcat(client_hello, (const char *)&random_bytes, 32);

	strlcat(tls_packet, (const char *)sizeof(client_hello), 3);
	strlcat(tls_packet, client_hello, sizeof(client_hello));

	strlcat(tls_packet, '\x00', 2); /* Session ID lenght */

	strlcat(tls_packet, sizeof(ciphers), 2);
	strlcat(tls_packet, &ciphers, sizeof(ciphers));

	strlcat(tls_packet, '\x01', 1); /* Compression Method */
	strlcat(tls_packet, '\x00', 1); /* Compression Methods */

	strlcat(tls_packet, "\x00\x00", 2); /* Extension Lenght */

	handshake = '\x16';
	strlcat(&handshake, 0x0200, 2); /* SSL version min */
	strlcat(&handshake, sizeof(tls_packet), 2);
	strlcat(&handshake, tls_packet, sizeof(tls_packet));

	write(s, handshake, sizeof(handshake));

	close(s);

	return 0;
}