Convert HelloVerifyRequest construction to WPACKET (c536b6be) · Commits · CYBER - Cyber Security / TS 103 523 MSP / ETS / ETS OpenSSL

ssl/d1_lib.c

+68 −48

Original line number	Diff line number	Diff line
		@@ -437,8 +437,8 @@ int DTLSv1_listen(SSL s, BIO_ADDR client)
		unsigned char cookie[DTLS1_COOKIE_LENGTH];
		unsigned char seq[SEQ_NUM_SIZE];
		const unsigned char *data;
		unsigned char p, buf;
		unsigned long reclen, fragoff, fraglen, msglen;
		unsigned char *buf;
		unsigned long fragoff, fraglen, msglen;
		unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
		BIO rbio, wbio;
		BUF_MEM *bufm;
		@@ -680,6 +680,10 @@ int DTLSv1_listen(SSL s, BIO_ADDR client)
		}

		if (next == LISTEN_SEND_VERIFY_REQUEST) {
		WPACKET wpkt;
		unsigned int version;
		size_t wreclen;

		/*
		* There was no cookie in the ClientHello so we need to send a
		* HelloVerifyRequest. If this fails we do not worry about trying
		@@ -703,60 +707,76 @@ int DTLSv1_listen(SSL s, BIO_ADDR client)
		return -1;
		}

		p = &buf[DTLS1_RT_HEADER_LENGTH];
		msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
		cookie, cookielen);

		*p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;

		/* Message length */
		l2n3(msglen, p);

		/* Message sequence number is always 0 for a HelloVerifyRequest */
		s2n(0, p);

		/*
		* We never fragment a HelloVerifyRequest, so fragment offset is 0
		* and fragment length is message length
		*/
		l2n3(0, p);
		l2n3(msglen, p);

		/* Set reclen equal to length of whole handshake message */
		reclen = msglen + DTLS1_HM_HEADER_LENGTH;

		/* Add the record header */
		p = buf;

		*(p++) = SSL3_RT_HANDSHAKE;
		/*
		* Special case: for hello verify request, client version 1.0 and we
		* haven't decided which version to use yet send back using version
		* 1.0 header: otherwise some clients will ignore it.
		*/
		if (s->method->version == DTLS_ANY_VERSION) {
		*(p++) = DTLS1_VERSION >> 8;
		*(p++) = DTLS1_VERSION & 0xff;
		} else {
		*(p++) = s->version >> 8;
		*(p++) = s->version & 0xff;
		}
		version = (s->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION
		: s->version;

		/* Construct the record and message headers */
		if (!WPACKET_init(&wpkt, s->init_buf)
		\|\| !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE)
		\|\| !WPACKET_put_bytes_u16(&wpkt, version)
		/*
		* Record sequence number is always the same as in the received
		* ClientHello
		* Record sequence number is always the same as in the
		* received ClientHello
		*/
		memcpy(p, seq, SEQ_NUM_SIZE);
		p += SEQ_NUM_SIZE;

		/* Length */
		s2n(reclen, p);
		\|\| !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE)
		/* End of record, start sub packet for message */
		\|\| !WPACKET_start_sub_packet_u16(&wpkt)
		/* Message type */
		\|\| !WPACKET_put_bytes_u8(&wpkt,
		DTLS1_MT_HELLO_VERIFY_REQUEST)
		/*
		* Message length - doesn't follow normal TLS convention:
		* the length isn't the last thing in the message header.
		* We'll need to fill this in later when we know the
		* length. Set it to zero for now
		*/
		\|\| !WPACKET_put_bytes_u24(&wpkt, 0)
		/*
		* Message sequence number is always 0 for a
		* HelloVerifyRequest
		*/
		\|\| !WPACKET_put_bytes_u16(&wpkt, 0)
		/*
		* We never fragment a HelloVerifyRequest, so fragment
		* offset is 0
		*/
		\|\| !WPACKET_put_bytes_u24(&wpkt, 0)
		/*
		* Fragment length is the same as message length, but
		* this is the last thing in the message header so we
		* can just start a sub-packet. No need to come back
		* later for this one.
		*/
		\|\| !WPACKET_start_sub_packet_u24(&wpkt)
		/* Create the actual HelloVerifyRequest body */
		\|\| !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen)
		/* Close message body */
		\|\| !WPACKET_close(&wpkt)
		/* Close record body */
		\|\| !WPACKET_close(&wpkt)
		\|\| !WPACKET_get_total_written(&wpkt, &wreclen)
		\|\| !WPACKET_finish(&wpkt)) {
		SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
		WPACKET_cleanup(&wpkt);
		/* This is fatal */
		return -1;
		}

		/*
		* Set reclen equal to length of whole record including record
		* header
		* Fix up the message len in the message header. Its the same as the
		* fragment len which has been filled in by WPACKET, so just copy
		* that. Destination for the message len is after the record header
		* plus one byte for the message content type. The source is the
		* last 3 bytes of the message header
		*/
		reclen += DTLS1_RT_HEADER_LENGTH;
		memcpy(&buf[DTLS1_RT_HEADER_LENGTH + 1],
		&buf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3],
		3);

		if (s->msg_callback)
		s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
		@@ -778,7 +798,7 @@ int DTLSv1_listen(SSL s, BIO_ADDR client)
		BIO_ADDR_free(tmpclient);
		tmpclient = NULL;

		if (BIO_write(wbio, buf, reclen) < (int)reclen) {
		if (BIO_write(wbio, buf, wreclen) < (int)wreclen) {
		if (BIO_should_retry(wbio)) {
		/*
		* Non-blocking IO...but we're stateless, so we're just

ssl/ssl_locl.h

+2 −3

Original line number	Diff line number	Diff line
		@@ -1950,8 +1950,7 @@ void dtls1_start_timer(SSL *s);
		void dtls1_stop_timer(SSL *s);
		__owur int dtls1_is_timer_expired(SSL *s);
		void dtls1_double_timeout(SSL *s);
		__owur unsigned int dtls_raw_hello_verify_request(unsigned char *buf,
		unsigned char *cookie,
		__owur int dtls_raw_hello_verify_request(WPACKET pkt, unsigned char cookie,
		unsigned char cookie_len);
		__owur int dtls1_send_newsession_ticket(SSL *s);
		__owur unsigned int dtls1_min_mtu(SSL *s);

ssl/statem/statem_srvr.c

+26 −25

Original line number	Diff line number	Diff line
		@@ -840,32 +840,21 @@ int tls_construct_hello_request(SSL *s)
		return 1;
		}

		unsigned int dtls_raw_hello_verify_request(unsigned char *buf,
		unsigned char *cookie,
		int dtls_raw_hello_verify_request(WPACKET pkt, unsigned char cookie,
		unsigned char cookie_len)
		{
		unsigned int msg_len;
		unsigned char *p;

		p = buf;
		/* Always use DTLS 1.0 version: see RFC 6347 */
		*(p++) = DTLS1_VERSION >> 8;
		*(p++) = DTLS1_VERSION & 0xFF;

		*(p++) = (unsigned char)cookie_len;
		memcpy(p, cookie, cookie_len);
		p += cookie_len;
		msg_len = p - buf;
		if (!WPACKET_put_bytes_u16(pkt, DTLS1_VERSION)
		\|\| !WPACKET_sub_memcpy_u8(pkt, cookie, cookie_len))
		return 0;

		return msg_len;
		return 1;
		}

		int dtls_construct_hello_verify_request(SSL *s)
		{
		unsigned int len;
		unsigned char *buf;

		buf = (unsigned char *)s->init_buf->data;
		size_t msglen;
		WPACKET pkt;

		if (s->ctx->app_gen_cookie_cb == NULL \|\|
		s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
		@@ -877,14 +866,26 @@ int dtls_construct_hello_verify_request(SSL *s)
		return 0;
		}

		len = dtls_raw_hello_verify_request(&buf[DTLS1_HM_HEADER_LENGTH],
		s->d1->cookie, s->d1->cookie_len);

		dtls1_set_message_header(s, DTLS1_MT_HELLO_VERIFY_REQUEST, len, 0, len);
		len += DTLS1_HM_HEADER_LENGTH;
		if (!WPACKET_init(&pkt, s->init_buf)
		\|\| !ssl_set_handshake_header2(s, &pkt,
		DTLS1_MT_HELLO_VERIFY_REQUEST)
		\|\| !dtls_raw_hello_verify_request(&pkt, s->d1->cookie,
		s->d1->cookie_len)
		/*
		* We don't call close_construct_packet() because we don't want
		* to buffer this message
		*/
		\|\| !WPACKET_close(&pkt)
		\|\| !WPACKET_get_length(&pkt, &msglen)
		\|\| !WPACKET_finish(&pkt)) {
		SSLerr(SSL_F_DTLS_CONSTRUCT_HELLO_VERIFY_REQUEST, ERR_R_INTERNAL_ERROR);
		WPACKET_cleanup(&pkt);
		ossl_statem_set_error(s);
		return 0;
		}

		/* number of bytes to write */
		s->init_num = len;
		s->init_num = (int)msglen;
		s->init_off = 0;

		return 1;

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