2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 /* ====================================================================
11 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
12 * ECC cipher suite support in OpenSSL originally developed by
13 * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
19 #include "../ssl_locl.h"
20 #include "statem_locl.h"
21 #include <openssl/buffer.h>
22 #include <openssl/objects.h>
23 #include <openssl/evp.h>
24 #include <openssl/x509.h>
27 * send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or
28 * SSL3_RT_CHANGE_CIPHER_SPEC)
30 int ssl3_do_write(SSL *s, int type)
34 ret = ssl3_write_bytes(s, type, &s->init_buf->data[s->init_off],
38 if (type == SSL3_RT_HANDSHAKE)
40 * should not be done for 'Hello Request's, but in that case we'll
41 * ignore the result anyway
43 if (!ssl3_finish_mac(s,
44 (unsigned char *)&s->init_buf->data[s->init_off],
48 if (ret == s->init_num) {
50 s->msg_callback(1, s->version, type, s->init_buf->data,
51 (size_t)(s->init_off + s->init_num), s,
60 int tls_construct_finished(SSL *s, const char *sender, int slen)
66 p = ssl_handshake_start(s);
68 i = s->method->ssl3_enc->final_finish_mac(s,
70 s->s3->tmp.finish_md);
73 s->s3->tmp.finish_md_len = i;
74 memcpy(p, s->s3->tmp.finish_md, i);
78 * Copy the finished so we can use it for renegotiation checks
81 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
82 memcpy(s->s3->previous_client_finished, s->s3->tmp.finish_md, i);
83 s->s3->previous_client_finished_len = i;
85 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
86 memcpy(s->s3->previous_server_finished, s->s3->tmp.finish_md, i);
87 s->s3->previous_server_finished_len = i;
90 if (!ssl_set_handshake_header(s, SSL3_MT_FINISHED, l)) {
91 SSLerr(SSL_F_TLS_CONSTRUCT_FINISHED, ERR_R_INTERNAL_ERROR);
98 #ifndef OPENSSL_NO_NEXTPROTONEG
100 * ssl3_take_mac calculates the Finished MAC for the handshakes messages seen
103 static void ssl3_take_mac(SSL *s)
108 * If no new cipher setup return immediately: other functions will set
109 * the appropriate error.
111 if (s->s3->tmp.new_cipher == NULL)
114 sender = s->method->ssl3_enc->server_finished_label;
115 slen = s->method->ssl3_enc->server_finished_label_len;
117 sender = s->method->ssl3_enc->client_finished_label;
118 slen = s->method->ssl3_enc->client_finished_label_len;
121 s->s3->tmp.peer_finish_md_len = s->method->ssl3_enc->final_finish_mac(s,
124 s->s3->tmp.peer_finish_md);
128 MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL *s, PACKET *pkt)
133 remain = PACKET_remaining(pkt);
135 * 'Change Cipher Spec' is just a single byte, which should already have
136 * been consumed by ssl_get_message() so there should be no bytes left,
137 * unless we're using DTLS1_BAD_VER, which has an extra 2 bytes
139 if (SSL_IS_DTLS(s)) {
140 if ((s->version == DTLS1_BAD_VER
141 && remain != DTLS1_CCS_HEADER_LENGTH + 1)
142 || (s->version != DTLS1_BAD_VER
143 && remain != DTLS1_CCS_HEADER_LENGTH - 1)) {
144 al = SSL_AD_ILLEGAL_PARAMETER;
145 SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC,
146 SSL_R_BAD_CHANGE_CIPHER_SPEC);
151 al = SSL_AD_ILLEGAL_PARAMETER;
152 SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC,
153 SSL_R_BAD_CHANGE_CIPHER_SPEC);
158 /* Check we have a cipher to change to */
159 if (s->s3->tmp.new_cipher == NULL) {
160 al = SSL_AD_UNEXPECTED_MESSAGE;
161 SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC, SSL_R_CCS_RECEIVED_EARLY);
165 s->s3->change_cipher_spec = 1;
166 if (!ssl3_do_change_cipher_spec(s)) {
167 al = SSL_AD_INTERNAL_ERROR;
168 SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
172 if (SSL_IS_DTLS(s)) {
173 dtls1_reset_seq_numbers(s, SSL3_CC_READ);
175 if (s->version == DTLS1_BAD_VER)
176 s->d1->handshake_read_seq++;
178 #ifndef OPENSSL_NO_SCTP
180 * Remember that a CCS has been received, so that an old key of
181 * SCTP-Auth can be deleted when a CCS is sent. Will be ignored if no
184 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_AUTH_CCS_RCVD, 1, NULL);
188 return MSG_PROCESS_CONTINUE_READING;
190 ssl3_send_alert(s, SSL3_AL_FATAL, al);
191 ossl_statem_set_error(s);
192 return MSG_PROCESS_ERROR;
195 MSG_PROCESS_RETURN tls_process_finished(SSL *s, PACKET *pkt)
199 /* If this occurs, we have missed a message */
200 if (!s->s3->change_cipher_spec) {
201 al = SSL_AD_UNEXPECTED_MESSAGE;
202 SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_GOT_A_FIN_BEFORE_A_CCS);
205 s->s3->change_cipher_spec = 0;
207 i = s->s3->tmp.peer_finish_md_len;
209 if ((unsigned long)i != PACKET_remaining(pkt)) {
210 al = SSL_AD_DECODE_ERROR;
211 SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_BAD_DIGEST_LENGTH);
215 if (CRYPTO_memcmp(PACKET_data(pkt), s->s3->tmp.peer_finish_md, i) != 0) {
216 al = SSL_AD_DECRYPT_ERROR;
217 SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_DIGEST_CHECK_FAILED);
222 * Copy the finished so we can use it for renegotiation checks
225 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
226 memcpy(s->s3->previous_client_finished, s->s3->tmp.peer_finish_md, i);
227 s->s3->previous_client_finished_len = i;
229 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
230 memcpy(s->s3->previous_server_finished, s->s3->tmp.peer_finish_md, i);
231 s->s3->previous_server_finished_len = i;
234 return MSG_PROCESS_FINISHED_READING;
236 ssl3_send_alert(s, SSL3_AL_FATAL, al);
237 ossl_statem_set_error(s);
238 return MSG_PROCESS_ERROR;
241 int tls_construct_change_cipher_spec(SSL *s)
245 p = (unsigned char *)s->init_buf->data;
253 unsigned long ssl3_output_cert_chain(SSL *s, CERT_PKEY *cpk)
256 unsigned long l = 3 + SSL_HM_HEADER_LENGTH(s);
258 if (!ssl_add_cert_chain(s, cpk, &l))
261 l -= 3 + SSL_HM_HEADER_LENGTH(s);
262 p = ssl_handshake_start(s);
266 if (!ssl_set_handshake_header(s, SSL3_MT_CERTIFICATE, l)) {
267 SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN, ERR_R_INTERNAL_ERROR);
270 return l + SSL_HM_HEADER_LENGTH(s);
273 WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst)
275 void (*cb) (const SSL *ssl, int type, int val) = NULL;
277 #ifndef OPENSSL_NO_SCTP
278 if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
280 ret = dtls_wait_for_dry(s);
281 if (ret != WORK_FINISHED_CONTINUE)
286 /* clean a few things up */
287 ssl3_cleanup_key_block(s);
289 if (!SSL_IS_DTLS(s)) {
291 * We don't do this in DTLS because we may still need the init_buf
292 * in case there are any unexpected retransmits
294 BUF_MEM_free(s->init_buf);
298 ssl_free_wbio_buffer(s);
302 if (!s->server || s->renegotiate == 2) {
303 /* skipped if we just sent a HelloRequest */
308 ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
310 s->ctx->stats.sess_accept_good++;
311 s->handshake_func = ossl_statem_accept;
313 ssl_update_cache(s, SSL_SESS_CACHE_CLIENT);
315 s->ctx->stats.sess_hit++;
317 s->handshake_func = ossl_statem_connect;
318 s->ctx->stats.sess_connect_good++;
321 if (s->info_callback != NULL)
322 cb = s->info_callback;
323 else if (s->ctx->info_callback != NULL)
324 cb = s->ctx->info_callback;
327 cb(s, SSL_CB_HANDSHAKE_DONE, 1);
329 if (SSL_IS_DTLS(s)) {
330 /* done with handshaking */
331 s->d1->handshake_read_seq = 0;
332 s->d1->handshake_write_seq = 0;
333 s->d1->next_handshake_write_seq = 0;
334 dtls1_clear_received_buffer(s);
338 return WORK_FINISHED_STOP;
341 int tls_get_message_header(SSL *s, int *mt)
343 /* s->init_num < SSL3_HM_HEADER_LENGTH */
344 int skip_message, i, recvd_type, al;
348 p = (unsigned char *)s->init_buf->data;
351 while (s->init_num < SSL3_HM_HEADER_LENGTH) {
352 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &recvd_type,
354 SSL3_HM_HEADER_LENGTH - s->init_num,
357 s->rwstate = SSL_READING;
360 if (recvd_type == SSL3_RT_CHANGE_CIPHER_SPEC) {
362 * A ChangeCipherSpec must be a single byte and may not occur
363 * in the middle of a handshake message.
365 if (s->init_num != 0 || i != 1 || p[0] != SSL3_MT_CCS) {
366 al = SSL_AD_UNEXPECTED_MESSAGE;
367 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER,
368 SSL_R_BAD_CHANGE_CIPHER_SPEC);
371 s->s3->tmp.message_type = *mt = SSL3_MT_CHANGE_CIPHER_SPEC;
373 s->init_msg = s->init_buf->data;
374 s->s3->tmp.message_size = i;
376 } else if (recvd_type != SSL3_RT_HANDSHAKE) {
377 al = SSL_AD_UNEXPECTED_MESSAGE;
378 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, SSL_R_CCS_RECEIVED_EARLY);
386 if (p[0] == SSL3_MT_HELLO_REQUEST)
388 * The server may always send 'Hello Request' messages --
389 * we are doing a handshake anyway now, so ignore them if
390 * their format is correct. Does not count for 'Finished'
393 if (p[1] == 0 && p[2] == 0 && p[3] == 0) {
398 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
399 p, SSL3_HM_HEADER_LENGTH, s,
400 s->msg_callback_arg);
402 } while (skip_message);
403 /* s->init_num == SSL3_HM_HEADER_LENGTH */
406 s->s3->tmp.message_type = *(p++);
408 if (RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
410 * Only happens with SSLv3+ in an SSLv2 backward compatible
413 * Total message size is the remaining record bytes to read
414 * plus the SSL3_HM_HEADER_LENGTH bytes that we already read
416 l = RECORD_LAYER_get_rrec_length(&s->rlayer)
417 + SSL3_HM_HEADER_LENGTH;
418 s->s3->tmp.message_size = l;
420 s->init_msg = s->init_buf->data;
421 s->init_num = SSL3_HM_HEADER_LENGTH;
424 /* BUF_MEM_grow takes an 'int' parameter */
425 if (l > (INT_MAX - SSL3_HM_HEADER_LENGTH)) {
426 al = SSL_AD_ILLEGAL_PARAMETER;
427 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, SSL_R_EXCESSIVE_MESSAGE_SIZE);
430 s->s3->tmp.message_size = l;
432 s->init_msg = s->init_buf->data + SSL3_HM_HEADER_LENGTH;
438 ssl3_send_alert(s, SSL3_AL_FATAL, al);
442 int tls_get_message_body(SSL *s, unsigned long *len)
448 if (s->s3->tmp.message_type == SSL3_MT_CHANGE_CIPHER_SPEC) {
449 /* We've already read everything in */
450 *len = (unsigned long)s->init_num;
455 n = s->s3->tmp.message_size - s->init_num;
457 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
458 &p[s->init_num], n, 0);
460 s->rwstate = SSL_READING;
468 #ifndef OPENSSL_NO_NEXTPROTONEG
470 * If receiving Finished, record MAC of prior handshake messages for
471 * Finished verification.
473 if (*s->init_buf->data == SSL3_MT_FINISHED)
477 /* Feed this message into MAC computation. */
478 if (RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
479 if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
481 SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_EVP_LIB);
482 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
487 s->msg_callback(0, SSL2_VERSION, 0, s->init_buf->data,
488 (size_t)s->init_num, s, s->msg_callback_arg);
490 if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
491 s->init_num + SSL3_HM_HEADER_LENGTH)) {
492 SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_EVP_LIB);
493 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
498 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data,
499 (size_t)s->init_num + SSL3_HM_HEADER_LENGTH, s,
500 s->msg_callback_arg);
504 * init_num should never be negative...should probably be declared
507 if (s->init_num < 0) {
508 SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_INTERNAL_ERROR);
509 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
513 *len = (unsigned long)s->init_num;
517 int ssl_cert_type(const X509 *x, const EVP_PKEY *pk)
519 if (pk == NULL && (pk = X509_get0_pubkey(x)) == NULL)
522 switch (EVP_PKEY_id(pk)) {
526 return SSL_PKEY_RSA_ENC;
528 return SSL_PKEY_DSA_SIGN;
529 #ifndef OPENSSL_NO_EC
533 #ifndef OPENSSL_NO_GOST
534 case NID_id_GostR3410_2001:
535 return SSL_PKEY_GOST01;
536 case NID_id_GostR3410_2012_256:
537 return SSL_PKEY_GOST12_256;
538 case NID_id_GostR3410_2012_512:
539 return SSL_PKEY_GOST12_512;
544 int ssl_verify_alarm_type(long type)
549 case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
550 case X509_V_ERR_UNABLE_TO_GET_CRL:
551 case X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER:
552 al = SSL_AD_UNKNOWN_CA;
554 case X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE:
555 case X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE:
556 case X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY:
557 case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
558 case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
559 case X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD:
560 case X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD:
561 case X509_V_ERR_CERT_NOT_YET_VALID:
562 case X509_V_ERR_CRL_NOT_YET_VALID:
563 case X509_V_ERR_CERT_UNTRUSTED:
564 case X509_V_ERR_CERT_REJECTED:
565 case X509_V_ERR_HOSTNAME_MISMATCH:
566 case X509_V_ERR_EMAIL_MISMATCH:
567 case X509_V_ERR_IP_ADDRESS_MISMATCH:
568 case X509_V_ERR_DANE_NO_MATCH:
569 case X509_V_ERR_EE_KEY_TOO_SMALL:
570 case X509_V_ERR_CA_KEY_TOO_SMALL:
571 case X509_V_ERR_CA_MD_TOO_WEAK:
572 al = SSL_AD_BAD_CERTIFICATE;
574 case X509_V_ERR_CERT_SIGNATURE_FAILURE:
575 case X509_V_ERR_CRL_SIGNATURE_FAILURE:
576 al = SSL_AD_DECRYPT_ERROR;
578 case X509_V_ERR_CERT_HAS_EXPIRED:
579 case X509_V_ERR_CRL_HAS_EXPIRED:
580 al = SSL_AD_CERTIFICATE_EXPIRED;
582 case X509_V_ERR_CERT_REVOKED:
583 al = SSL_AD_CERTIFICATE_REVOKED;
585 case X509_V_ERR_UNSPECIFIED:
586 case X509_V_ERR_OUT_OF_MEM:
587 case X509_V_ERR_INVALID_CALL:
588 case X509_V_ERR_STORE_LOOKUP:
589 al = SSL_AD_INTERNAL_ERROR;
591 case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT:
592 case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN:
593 case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY:
594 case X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE:
595 case X509_V_ERR_CERT_CHAIN_TOO_LONG:
596 case X509_V_ERR_PATH_LENGTH_EXCEEDED:
597 case X509_V_ERR_INVALID_CA:
598 al = SSL_AD_UNKNOWN_CA;
600 case X509_V_ERR_APPLICATION_VERIFICATION:
601 al = SSL_AD_HANDSHAKE_FAILURE;
603 case X509_V_ERR_INVALID_PURPOSE:
604 al = SSL_AD_UNSUPPORTED_CERTIFICATE;
607 al = SSL_AD_CERTIFICATE_UNKNOWN;
613 int ssl_allow_compression(SSL *s)
615 if (s->options & SSL_OP_NO_COMPRESSION)
617 return ssl_security(s, SSL_SECOP_COMPRESSION, 0, 0, NULL);
620 static int version_cmp(const SSL *s, int a, int b)
622 int dtls = SSL_IS_DTLS(s);
627 return a < b ? -1 : 1;
628 return DTLS_VERSION_LT(a, b) ? -1 : 1;
633 const SSL_METHOD *(*cmeth) (void);
634 const SSL_METHOD *(*smeth) (void);
637 #if TLS_MAX_VERSION != TLS1_2_VERSION
638 # error Code needs update for TLS_method() support beyond TLS1_2_VERSION.
641 static const version_info tls_version_table[] = {
642 #ifndef OPENSSL_NO_TLS1_2
643 {TLS1_2_VERSION, tlsv1_2_client_method, tlsv1_2_server_method},
645 {TLS1_2_VERSION, NULL, NULL},
647 #ifndef OPENSSL_NO_TLS1_1
648 {TLS1_1_VERSION, tlsv1_1_client_method, tlsv1_1_server_method},
650 {TLS1_1_VERSION, NULL, NULL},
652 #ifndef OPENSSL_NO_TLS1
653 {TLS1_VERSION, tlsv1_client_method, tlsv1_server_method},
655 {TLS1_VERSION, NULL, NULL},
657 #ifndef OPENSSL_NO_SSL3
658 {SSL3_VERSION, sslv3_client_method, sslv3_server_method},
660 {SSL3_VERSION, NULL, NULL},
665 #if DTLS_MAX_VERSION != DTLS1_2_VERSION
666 # error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
669 static const version_info dtls_version_table[] = {
670 #ifndef OPENSSL_NO_DTLS1_2
671 {DTLS1_2_VERSION, dtlsv1_2_client_method, dtlsv1_2_server_method},
673 {DTLS1_2_VERSION, NULL, NULL},
675 #ifndef OPENSSL_NO_DTLS1
676 {DTLS1_VERSION, dtlsv1_client_method, dtlsv1_server_method},
677 {DTLS1_BAD_VER, dtls_bad_ver_client_method, NULL},
679 {DTLS1_VERSION, NULL, NULL},
680 {DTLS1_BAD_VER, NULL, NULL},
686 * ssl_method_error - Check whether an SSL_METHOD is enabled.
688 * @s: The SSL handle for the candidate method
689 * @method: the intended method.
691 * Returns 0 on success, or an SSL error reason on failure.
693 static int ssl_method_error(const SSL *s, const SSL_METHOD *method)
695 int version = method->version;
697 if ((s->min_proto_version != 0 &&
698 version_cmp(s, version, s->min_proto_version) < 0) ||
699 ssl_security(s, SSL_SECOP_VERSION, 0, version, NULL) == 0)
700 return SSL_R_VERSION_TOO_LOW;
702 if (s->max_proto_version != 0 &&
703 version_cmp(s, version, s->max_proto_version) > 0)
704 return SSL_R_VERSION_TOO_HIGH;
706 if ((s->options & method->mask) != 0)
707 return SSL_R_UNSUPPORTED_PROTOCOL;
708 if ((method->flags & SSL_METHOD_NO_SUITEB) != 0 && tls1_suiteb(s))
709 return SSL_R_AT_LEAST_TLS_1_2_NEEDED_IN_SUITEB_MODE;
710 else if ((method->flags & SSL_METHOD_NO_FIPS) != 0 && FIPS_mode())
711 return SSL_R_AT_LEAST_TLS_1_0_NEEDED_IN_FIPS_MODE;
717 * ssl_version_supported - Check that the specified `version` is supported by
720 * @s: The SSL handle for the candidate method
721 * @version: Protocol version to test against
723 * Returns 1 when supported, otherwise 0
725 int ssl_version_supported(const SSL *s, int version)
727 const version_info *vent;
728 const version_info *table;
730 switch (s->method->version) {
732 /* Version should match method version for non-ANY method */
733 return version_cmp(s, version, s->version) == 0;
734 case TLS_ANY_VERSION:
735 table = tls_version_table;
737 case DTLS_ANY_VERSION:
738 table = dtls_version_table;
743 vent->version != 0 && version_cmp(s, version, vent->version) <= 0;
745 if (vent->cmeth != NULL &&
746 version_cmp(s, version, vent->version) == 0 &&
747 ssl_method_error(s, vent->cmeth()) == 0) {
755 * ssl_check_version_downgrade - In response to RFC7507 SCSV version
756 * fallback indication from a client check whether we're using the highest
757 * supported protocol version.
759 * @s server SSL handle.
761 * Returns 1 when using the highest enabled version, 0 otherwise.
763 int ssl_check_version_downgrade(SSL *s)
765 const version_info *vent;
766 const version_info *table;
769 * Check that the current protocol is the highest enabled version
770 * (according to s->ctx->method, as version negotiation may have changed
773 if (s->version == s->ctx->method->version)
777 * Apparently we're using a version-flexible SSL_METHOD (not at its
778 * highest protocol version).
780 if (s->ctx->method->version == TLS_method()->version)
781 table = tls_version_table;
782 else if (s->ctx->method->version == DTLS_method()->version)
783 table = dtls_version_table;
785 /* Unexpected state; fail closed. */
789 for (vent = table; vent->version != 0; ++vent) {
790 if (vent->smeth != NULL && ssl_method_error(s, vent->smeth()) == 0)
791 return s->version == vent->version;
797 * ssl_set_version_bound - set an upper or lower bound on the supported (D)TLS
798 * protocols, provided the initial (D)TLS method is version-flexible. This
799 * function sanity-checks the proposed value and makes sure the method is
800 * version-flexible, then sets the limit if all is well.
802 * @method_version: The version of the current SSL_METHOD.
803 * @version: the intended limit.
804 * @bound: pointer to limit to be updated.
806 * Returns 1 on success, 0 on failure.
808 int ssl_set_version_bound(int method_version, int version, int *bound)
816 * Restrict TLS methods to TLS protocol versions.
817 * Restrict DTLS methods to DTLS protocol versions.
818 * Note, DTLS version numbers are decreasing, use comparison macros.
820 * Note that for both lower-bounds we use explicit versions, not
821 * (D)TLS_MIN_VERSION. This is because we don't want to break user
822 * configurations. If the MIN (supported) version ever rises, the user's
823 * "floor" remains valid even if no longer available. We don't expect the
824 * MAX ceiling to ever get lower, so making that variable makes sense.
826 switch (method_version) {
829 * XXX For fixed version methods, should we always fail and not set any
830 * bounds, always succeed and not set any bounds, or set the bounds and
831 * arrange to fail later if they are not met? At present fixed-version
832 * methods are not subject to controls that disable individual protocol
837 case TLS_ANY_VERSION:
838 if (version < SSL3_VERSION || version > TLS_MAX_VERSION)
842 case DTLS_ANY_VERSION:
843 if (DTLS_VERSION_GT(version, DTLS_MAX_VERSION) ||
844 DTLS_VERSION_LT(version, DTLS1_BAD_VER))
854 * ssl_choose_server_version - Choose server (D)TLS version. Called when the
855 * client HELLO is received to select the final server protocol version and
856 * the version specific method.
858 * @s: server SSL handle.
860 * Returns 0 on success or an SSL error reason number on failure.
862 int ssl_choose_server_version(SSL *s)
865 * With version-flexible methods we have an initial state with:
867 * s->method->version == (D)TLS_ANY_VERSION,
868 * s->version == (D)TLS_MAX_VERSION.
870 * So we detect version-flexible methods via the method version, not the
873 int server_version = s->method->version;
874 int client_version = s->client_version;
875 const version_info *vent;
876 const version_info *table;
879 switch (server_version) {
881 if (version_cmp(s, client_version, s->version) < 0)
882 return SSL_R_WRONG_SSL_VERSION;
884 * If this SSL handle is not from a version flexible method we don't
885 * (and never did) check min/max FIPS or Suite B constraints. Hope
886 * that's OK. It is up to the caller to not choose fixed protocol
887 * versions they don't want. If not, then easy to fix, just return
888 * ssl_method_error(s, s->method)
891 case TLS_ANY_VERSION:
892 table = tls_version_table;
894 case DTLS_ANY_VERSION:
895 table = dtls_version_table;
899 for (vent = table; vent->version != 0; ++vent) {
900 const SSL_METHOD *method;
902 if (vent->smeth == NULL ||
903 version_cmp(s, client_version, vent->version) < 0)
905 method = vent->smeth();
906 if (ssl_method_error(s, method) == 0) {
907 s->version = vent->version;
913 return disabled ? SSL_R_UNSUPPORTED_PROTOCOL : SSL_R_VERSION_TOO_LOW;
917 * ssl_choose_client_version - Choose client (D)TLS version. Called when the
918 * server HELLO is received to select the final client protocol version and
919 * the version specific method.
921 * @s: client SSL handle.
922 * @version: The proposed version from the server's HELLO.
924 * Returns 0 on success or an SSL error reason number on failure.
926 int ssl_choose_client_version(SSL *s, int version)
928 const version_info *vent;
929 const version_info *table;
931 switch (s->method->version) {
933 if (version != s->version)
934 return SSL_R_WRONG_SSL_VERSION;
936 * If this SSL handle is not from a version flexible method we don't
937 * (and never did) check min/max, FIPS or Suite B constraints. Hope
938 * that's OK. It is up to the caller to not choose fixed protocol
939 * versions they don't want. If not, then easy to fix, just return
940 * ssl_method_error(s, s->method)
943 case TLS_ANY_VERSION:
944 table = tls_version_table;
946 case DTLS_ANY_VERSION:
947 table = dtls_version_table;
951 for (vent = table; vent->version != 0; ++vent) {
952 const SSL_METHOD *method;
955 if (version != vent->version)
957 if (vent->cmeth == NULL)
959 method = vent->cmeth();
960 err = ssl_method_error(s, method);
964 s->version = version;
968 return SSL_R_UNSUPPORTED_PROTOCOL;
972 * ssl_get_client_min_max_version - get minimum and maximum client version
973 * @s: The SSL connection
974 * @min_version: The minimum supported version
975 * @max_version: The maximum supported version
977 * Work out what version we should be using for the initial ClientHello if the
978 * version is initially (D)TLS_ANY_VERSION. We apply any explicit SSL_OP_NO_xxx
979 * options, the MinProtocol and MaxProtocol configuration commands, any Suite B
980 * or FIPS_mode() constraints and any floor imposed by the security level here,
981 * so we don't advertise the wrong protocol version to only reject the outcome later.
983 * Computing the right floor matters. If, e.g., TLS 1.0 and 1.2 are enabled,
984 * TLS 1.1 is disabled, but the security level, Suite-B and/or MinProtocol
985 * only allow TLS 1.2, we want to advertise TLS1.2, *not* TLS1.
987 * Returns 0 on success or an SSL error reason number on failure. On failure
988 * min_version and max_version will also be set to 0.
990 int ssl_get_client_min_max_version(const SSL *s, int *min_version,
995 const SSL_METHOD *single = NULL;
996 const SSL_METHOD *method;
997 const version_info *table;
998 const version_info *vent;
1000 switch (s->method->version) {
1003 * If this SSL handle is not from a version flexible method we don't
1004 * (and never did) check min/max FIPS or Suite B constraints. Hope
1005 * that's OK. It is up to the caller to not choose fixed protocol
1006 * versions they don't want. If not, then easy to fix, just return
1007 * ssl_method_error(s, s->method)
1009 *min_version = *max_version = s->version;
1011 case TLS_ANY_VERSION:
1012 table = tls_version_table;
1014 case DTLS_ANY_VERSION:
1015 table = dtls_version_table;
1020 * SSL_OP_NO_X disables all protocols above X *if* there are some protocols
1021 * below X enabled. This is required in order to maintain the "version
1022 * capability" vector contiguous. Any versions with a NULL client method
1023 * (protocol version client is disabled at compile-time) is also a "hole".
1025 * Our initial state is hole == 1, version == 0. That is, versions above
1026 * the first version in the method table are disabled (a "hole" above
1027 * the valid protocol entries) and we don't have a selected version yet.
1029 * Whenever "hole == 1", and we hit an enabled method, its version becomes
1030 * the selected version, and the method becomes a candidate "single"
1031 * method. We're no longer in a hole, so "hole" becomes 0.
1033 * If "hole == 0" and we hit an enabled method, then "single" is cleared,
1034 * as we support a contiguous range of at least two methods. If we hit
1035 * a disabled method, then hole becomes true again, but nothing else
1036 * changes yet, because all the remaining methods may be disabled too.
1037 * If we again hit an enabled method after the new hole, it becomes
1038 * selected, as we start from scratch.
1040 *min_version = version = 0;
1042 for (vent = table; vent->version != 0; ++vent) {
1044 * A table entry with a NULL client method is still a hole in the
1045 * "version capability" vector.
1047 if (vent->cmeth == NULL) {
1051 method = vent->cmeth();
1052 if (ssl_method_error(s, method) != 0) {
1056 *min_version = method->version;
1058 version = (single = method)->version;
1059 *min_version = version;
1064 *max_version = version;
1066 /* Fail if everything is disabled */
1068 return SSL_R_NO_PROTOCOLS_AVAILABLE;
1074 * ssl_set_client_hello_version - Work out what version we should be using for
1075 * the initial ClientHello.
1077 * @s: client SSL handle.
1079 * Returns 0 on success or an SSL error reason number on failure.
1081 int ssl_set_client_hello_version(SSL *s)
1083 int ver_min, ver_max, ret;
1085 ret = ssl_get_client_min_max_version(s, &ver_min, &ver_max);
1090 s->client_version = s->version = ver_max;