s23_srvr.c

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						s->version=TLS1_VERSION;
						/* type=2; */ /* done later to survive restarts */
						s->state=SSL23_ST_SR_CLNT_HELLO_B;
						}
					else if (!(s->options & SSL_OP_NO_SSLv3))
						{
						s->version=SSL3_VERSION;
						/* type=2; */
						s->state=SSL23_ST_SR_CLNT_HELLO_B;
						}
					else if (!(s->options & SSL_OP_NO_SSLv2))
						{
						type=1;
						}
					}
				else if (!(s->options & SSL_OP_NO_SSLv3))
					{
					s->version=SSL3_VERSION;
					/* type=2; */
					s->state=SSL23_ST_SR_CLNT_HELLO_B;
					}
				else if (!(s->options & SSL_OP_NO_SSLv2))
					type=1;

				}
			}
		else if ((p[0] == SSL3_RT_HANDSHAKE) &&
			 (p[1] == SSL3_VERSION_MAJOR) &&
			 (p[5] == SSL3_MT_CLIENT_HELLO) &&
			 ((p[3] == 0 && p[4] < 5 /* silly record length? */)
				|| (p[9] == p[1])))
			{
			/*
			 * SSLv3 or tls1 header
			 */
			
			v[0]=p[1]; /* major version (= SSL3_VERSION_MAJOR) */
			/* We must look at client_version inside the Client Hello message
			 * to get the correct minor version.
			 * However if we have only a pathologically small fragment of the
			 * Client Hello message, this would be difficult, and we'd have
			 * to read more records to find out.
			 * No known SSL 3.0 client fragments ClientHello like this,
			 * so we simply assume TLS 1.0 to avoid protocol version downgrade
			 * attacks. */
			if (p[3] == 0 && p[4] < 6)
				{
#if 0
				SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_TOO_SMALL);
				goto err;
#else
				v[1] = TLS1_VERSION_MINOR;
#endif
				}
			else
				v[1]=p[10]; /* minor version according to client_version */
			if (v[1] >= TLS1_VERSION_MINOR)
				{
				if (!(s->options & SSL_OP_NO_TLSv1))
					{
					s->version=TLS1_VERSION;
					type=3;
					}
				else if (!(s->options & SSL_OP_NO_SSLv3))
					{
					s->version=SSL3_VERSION;
					type=3;
					}
				}
			else
				{
				/* client requests SSL 3.0 */
				if (!(s->options & SSL_OP_NO_SSLv3))
					{
					s->version=SSL3_VERSION;
					type=3;
					}
				else if (!(s->options & SSL_OP_NO_TLSv1))
					{
					/* we won't be able to use TLS of course,
					 * but this will send an appropriate alert */
					s->version=TLS1_VERSION;
					type=3;
					}
				}
			}
		else if ((strncmp("GET ", (char *)p,4) == 0) ||
			 (strncmp("POST ",(char *)p,5) == 0) ||
			 (strncmp("HEAD ",(char *)p,5) == 0) ||
			 (strncmp("PUT ", (char *)p,4) == 0))
			{
			SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_HTTP_REQUEST);
			goto err;
			}
		else if (strncmp("CONNECT",(char *)p,7) == 0)
			{
			SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_HTTPS_PROXY_REQUEST);
			goto err;
			}
		}

	if (s->state == SSL23_ST_SR_CLNT_HELLO_B)
		{
		/* we have SSLv3/TLSv1 in an SSLv2 header
		 * (other cases skip this state) */

		type=2;
		p=s->packet;
		v[0] = p[3]; /* == SSL3_VERSION_MAJOR */
		v[1] = p[4];

		n=((p[0]&0x7f)<<8)|p[1];
		if (n > (1024*4))
			{
			SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_TOO_LARGE);
			goto err;
			}

		j=ssl23_read_bytes(s,n+2);
		if (j <= 0) return(j);

		ssl3_finish_mac(s, s->packet+2, s->packet_length-2);
		if (s->msg_callback)
			s->msg_callback(0, SSL2_VERSION, 0, s->packet+2, s->packet_length-2, s, s->msg_callback_arg); /* CLIENT-HELLO */

		p=s->packet;
		p+=5;
		n2s(p,csl);
		n2s(p,sil);
		n2s(p,cl);
		d=(unsigned char *)s->init_buf->data;
		if ((csl+sil+cl+11) != s->packet_length)
			{
			SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_LENGTH_MISMATCH);
			goto err;
			}

		/* record header: msg_type ... */
		*(d++) = SSL3_MT_CLIENT_HELLO;
		/* ... and length (actual value will be written later) */
		d_len = d;
		d += 3;

		/* client_version */
		*(d++) = SSL3_VERSION_MAJOR; /* == v[0] */
		*(d++) = v[1];

		/* lets populate the random area */
		/* get the challenge_length */
		i=(cl > SSL3_RANDOM_SIZE)?SSL3_RANDOM_SIZE:cl;
		memset(d,0,SSL3_RANDOM_SIZE);
		memcpy(&(d[SSL3_RANDOM_SIZE-i]),&(p[csl+sil]),i);
		d+=SSL3_RANDOM_SIZE;

		/* no session-id reuse */
		*(d++)=0;

		/* ciphers */
		j=0;
		dd=d;
		d+=2;
		for (i=0; i<csl; i+=3)
			{
			if (p[i] != 0) continue;
			*(d++)=p[i+1];
			*(d++)=p[i+2];
			j+=2;
			}
		s2n(j,dd);

		/* COMPRESSION */
		*(d++)=1;
		*(d++)=0;
		
		i = (d-(unsigned char *)s->init_buf->data) - 4;
		l2n3((long)i, d_len);

		/* get the data reused from the init_buf */
		s->s3->tmp.reuse_message=1;
		s->s3->tmp.message_type=SSL3_MT_CLIENT_HELLO;
		s->s3->tmp.message_size=i;
		}

	/* imaginary new state (for program structure): */
	/* s->state = SSL23_SR_CLNT_HELLO_C */

	if (type == 1)
		{
#ifdef OPENSSL_NO_SSL2
		SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_UNSUPPORTED_PROTOCOL);
		goto err;
#else
		/* we are talking sslv2 */
		/* we need to clean up the SSLv3/TLSv1 setup and put in the
		 * sslv2 stuff. */

		if (s->s2 == NULL)
			{
			if (!ssl2_new(s))
				goto err;
			}
		else
			ssl2_clear(s);

		if (s->s3 != NULL) ssl3_free(s);

		if (!BUF_MEM_grow_clean(s->init_buf,
			SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER))
			{
			goto err;
			}

		s->state=SSL2_ST_GET_CLIENT_HELLO_A;
		if (s->options & SSL_OP_NO_TLSv1 && s->options & SSL_OP_NO_SSLv3)
			s->s2->ssl2_rollback=0;
		else
			/* reject SSL 2.0 session if client supports SSL 3.0 or TLS 1.0
			 * (SSL 3.0 draft/RFC 2246, App. E.2) */
			s->s2->ssl2_rollback=1;

		/* setup the n bytes we have read so we get them from
		 * the sslv2 buffer */
		s->rstate=SSL_ST_READ_HEADER;
		s->packet_length=n;
		s->packet= &(s->s2->rbuf[0]);
		memcpy(s->packet,buf,n);
		s->s2->rbuf_left=n;
		s->s2->rbuf_offs=0;

		s->method=SSLv2_server_method();
		s->handshake_func=s->method->ssl_accept;
#endif
		}

	if ((type == 2) || (type == 3))
		{
		/* we have SSLv3/TLSv1 (type 2: SSL2 style, type 3: SSL3/TLS style) */

		if (!ssl_init_wbio_buffer(s,1)) goto err;

		/* we are in this state */
		s->state=SSL3_ST_SR_CLNT_HELLO_A;

		if (type == 3)
			{
			/* put the 'n' bytes we have read into the input buffer
			 * for SSLv3 */
			s->rstate=SSL_ST_READ_HEADER;
			s->packet_length=n;
			s->packet= &(s->s3->rbuf.buf[0]);
			memcpy(s->packet,buf,n);
			s->s3->rbuf.left=n;
			s->s3->rbuf.offset=0;
			}
		else
			{
			s->packet_length=0;
			s->s3->rbuf.left=0;
			s->s3->rbuf.offset=0;
			}

		if (s->version == TLS1_VERSION)
			s->method = TLSv1_server_method();
		else
			s->method = SSLv3_server_method();
#if 0 /* ssl3_get_client_hello does this */
		s->client_version=(v[0]<<8)|v[1];
#endif
		s->handshake_func=s->method->ssl_accept;
		}
	
	if ((type < 1) || (type > 3))
		{
		/* bad, very bad */
		SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_UNKNOWN_PROTOCOL);
		goto err;
		}
	s->init_num=0;

	if (buf != buf_space) OPENSSL_free(buf);
	s->first_packet=1;
	return(SSL_accept(s));
err:
	if (buf != buf_space) OPENSSL_free(buf);
	return(-1);
	}