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;
337 return WORK_FINISHED_STOP;
340 int tls_get_message_header(SSL *s, int *mt)
342 /* s->init_num < SSL3_HM_HEADER_LENGTH */
343 int skip_message, i, recvd_type, al;
347 p = (unsigned char *)s->init_buf->data;
350 while (s->init_num < SSL3_HM_HEADER_LENGTH) {
351 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &recvd_type,
352 &p[s->init_num], SSL3_HM_HEADER_LENGTH - s->init_num, 0);
354 s->rwstate = SSL_READING;
357 if (recvd_type == SSL3_RT_CHANGE_CIPHER_SPEC) {
359 * A ChangeCipherSpec must be a single byte and may not occur
360 * in the middle of a handshake message.
362 if (s->init_num != 0 || i != 1 || p[0] != SSL3_MT_CCS) {
363 al = SSL_AD_UNEXPECTED_MESSAGE;
364 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER,
365 SSL_R_BAD_CHANGE_CIPHER_SPEC);
368 s->s3->tmp.message_type = *mt = SSL3_MT_CHANGE_CIPHER_SPEC;
370 s->s3->tmp.message_size = i;
372 } else if (recvd_type != SSL3_RT_HANDSHAKE) {
373 al = SSL_AD_UNEXPECTED_MESSAGE;
374 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, SSL_R_CCS_RECEIVED_EARLY);
382 if (p[0] == SSL3_MT_HELLO_REQUEST)
384 * The server may always send 'Hello Request' messages --
385 * we are doing a handshake anyway now, so ignore them if
386 * their format is correct. Does not count for 'Finished'
389 if (p[1] == 0 && p[2] == 0 && p[3] == 0) {
394 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
395 p, SSL3_HM_HEADER_LENGTH, s,
396 s->msg_callback_arg);
398 } while (skip_message);
399 /* s->init_num == SSL3_HM_HEADER_LENGTH */
402 s->s3->tmp.message_type = *(p++);
404 if(RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
406 * Only happens with SSLv3+ in an SSLv2 backward compatible
410 * Total message size is the remaining record bytes to read
411 * plus the SSL3_HM_HEADER_LENGTH bytes that we already read
413 l = RECORD_LAYER_get_rrec_length(&s->rlayer)
414 + SSL3_HM_HEADER_LENGTH;
415 if (l && !BUF_MEM_grow_clean(s->init_buf, (int)l)) {
416 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, ERR_R_BUF_LIB);
419 s->s3->tmp.message_size = l;
421 s->init_msg = s->init_buf->data;
422 s->init_num = SSL3_HM_HEADER_LENGTH;
425 /* BUF_MEM_grow takes an 'int' parameter */
426 if (l > (INT_MAX - SSL3_HM_HEADER_LENGTH)) {
427 al = SSL_AD_ILLEGAL_PARAMETER;
428 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, SSL_R_EXCESSIVE_MESSAGE_SIZE);
431 if (l && !BUF_MEM_grow_clean(s->init_buf,
432 (int)l + SSL3_HM_HEADER_LENGTH)) {
433 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, ERR_R_BUF_LIB);
436 s->s3->tmp.message_size = l;
438 s->init_msg = s->init_buf->data + SSL3_HM_HEADER_LENGTH;
444 ssl3_send_alert(s, SSL3_AL_FATAL, al);
449 int tls_get_message_body(SSL *s, unsigned long *len)
455 if (s->s3->tmp.message_type == SSL3_MT_CHANGE_CIPHER_SPEC) {
456 /* We've already read everything in */
457 *len = (unsigned long)s->init_num;
462 n = s->s3->tmp.message_size - s->init_num;
464 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
465 &p[s->init_num], n, 0);
467 s->rwstate = SSL_READING;
475 #ifndef OPENSSL_NO_NEXTPROTONEG
477 * If receiving Finished, record MAC of prior handshake messages for
478 * Finished verification.
480 if (*s->init_buf->data == SSL3_MT_FINISHED)
484 /* Feed this message into MAC computation. */
485 if(RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
486 if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
488 SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_EVP_LIB);
489 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
494 s->msg_callback(0, SSL2_VERSION, 0, s->init_buf->data,
495 (size_t)s->init_num, s, s->msg_callback_arg);
497 if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
498 s->init_num + SSL3_HM_HEADER_LENGTH)) {
499 SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_EVP_LIB);
500 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
505 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data,
506 (size_t)s->init_num + SSL3_HM_HEADER_LENGTH, s,
507 s->msg_callback_arg);
511 * init_num should never be negative...should probably be declared
514 if (s->init_num < 0) {
515 SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_INTERNAL_ERROR);
516 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
520 *len = (unsigned long)s->init_num;
524 int ssl_cert_type(X509 *x, EVP_PKEY *pk)
527 (pk = X509_get0_pubkey(x)) == NULL)
530 switch (EVP_PKEY_id(pk)) {
534 return SSL_PKEY_RSA_ENC;
536 return SSL_PKEY_DSA_SIGN;
537 #ifndef OPENSSL_NO_EC
541 #ifndef OPENSSL_NO_GOST
542 case NID_id_GostR3410_2001:
543 return SSL_PKEY_GOST01;
544 case NID_id_GostR3410_2012_256:
545 return SSL_PKEY_GOST12_256;
546 case NID_id_GostR3410_2012_512:
547 return SSL_PKEY_GOST12_512;
552 int ssl_verify_alarm_type(long type)
557 case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
558 case X509_V_ERR_UNABLE_TO_GET_CRL:
559 case X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER:
560 al = SSL_AD_UNKNOWN_CA;
562 case X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE:
563 case X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE:
564 case X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY:
565 case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
566 case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
567 case X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD:
568 case X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD:
569 case X509_V_ERR_CERT_NOT_YET_VALID:
570 case X509_V_ERR_CRL_NOT_YET_VALID:
571 case X509_V_ERR_CERT_UNTRUSTED:
572 case X509_V_ERR_CERT_REJECTED:
573 case X509_V_ERR_HOSTNAME_MISMATCH:
574 case X509_V_ERR_EMAIL_MISMATCH:
575 case X509_V_ERR_IP_ADDRESS_MISMATCH:
576 case X509_V_ERR_DANE_NO_MATCH:
577 case X509_V_ERR_EE_KEY_TOO_SMALL:
578 case X509_V_ERR_CA_KEY_TOO_SMALL:
579 case X509_V_ERR_CA_MD_TOO_WEAK:
580 al = SSL_AD_BAD_CERTIFICATE;
582 case X509_V_ERR_CERT_SIGNATURE_FAILURE:
583 case X509_V_ERR_CRL_SIGNATURE_FAILURE:
584 al = SSL_AD_DECRYPT_ERROR;
586 case X509_V_ERR_CERT_HAS_EXPIRED:
587 case X509_V_ERR_CRL_HAS_EXPIRED:
588 al = SSL_AD_CERTIFICATE_EXPIRED;
590 case X509_V_ERR_CERT_REVOKED:
591 al = SSL_AD_CERTIFICATE_REVOKED;
593 case X509_V_ERR_UNSPECIFIED:
594 case X509_V_ERR_OUT_OF_MEM:
595 case X509_V_ERR_INVALID_CALL:
596 case X509_V_ERR_STORE_LOOKUP:
597 al = SSL_AD_INTERNAL_ERROR;
599 case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT:
600 case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN:
601 case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY:
602 case X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE:
603 case X509_V_ERR_CERT_CHAIN_TOO_LONG:
604 case X509_V_ERR_PATH_LENGTH_EXCEEDED:
605 case X509_V_ERR_INVALID_CA:
606 al = SSL_AD_UNKNOWN_CA;
608 case X509_V_ERR_APPLICATION_VERIFICATION:
609 al = SSL_AD_HANDSHAKE_FAILURE;
611 case X509_V_ERR_INVALID_PURPOSE:
612 al = SSL_AD_UNSUPPORTED_CERTIFICATE;
615 al = SSL_AD_CERTIFICATE_UNKNOWN;
621 int ssl_allow_compression(SSL *s)
623 if (s->options & SSL_OP_NO_COMPRESSION)
625 return ssl_security(s, SSL_SECOP_COMPRESSION, 0, 0, NULL);
628 static int version_cmp(const SSL *s, int a, int b)
630 int dtls = SSL_IS_DTLS(s);
635 return a < b ? -1 : 1;
636 return DTLS_VERSION_LT(a, b) ? -1 : 1;
641 const SSL_METHOD *(*cmeth)(void);
642 const SSL_METHOD *(*smeth)(void);
645 #if TLS_MAX_VERSION != TLS1_2_VERSION
646 # error Code needs update for TLS_method() support beyond TLS1_2_VERSION.
649 static const version_info tls_version_table[] = {
650 #ifndef OPENSSL_NO_TLS1_2
651 { TLS1_2_VERSION, tlsv1_2_client_method, tlsv1_2_server_method },
653 { TLS1_2_VERSION, NULL, NULL },
655 #ifndef OPENSSL_NO_TLS1_1
656 { TLS1_1_VERSION, tlsv1_1_client_method, tlsv1_1_server_method },
658 { TLS1_1_VERSION, NULL, NULL },
660 #ifndef OPENSSL_NO_TLS1
661 { TLS1_VERSION, tlsv1_client_method, tlsv1_server_method },
663 { TLS1_VERSION, NULL, NULL },
665 #ifndef OPENSSL_NO_SSL3
666 { SSL3_VERSION, sslv3_client_method, sslv3_server_method },
668 { SSL3_VERSION, NULL, NULL },
673 #if DTLS_MAX_VERSION != DTLS1_2_VERSION
674 # error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
677 static const version_info dtls_version_table[] = {
678 #ifndef OPENSSL_NO_DTLS1_2
679 { DTLS1_2_VERSION, dtlsv1_2_client_method, dtlsv1_2_server_method },
681 { DTLS1_2_VERSION, NULL, NULL },
683 #ifndef OPENSSL_NO_DTLS1
684 { DTLS1_VERSION, dtlsv1_client_method, dtlsv1_server_method },
686 { DTLS1_VERSION, NULL, NULL },
692 * ssl_method_error - Check whether an SSL_METHOD is enabled.
694 * @s: The SSL handle for the candidate method
695 * @method: the intended method.
697 * Returns 0 on success, or an SSL error reason on failure.
699 static int ssl_method_error(const SSL *s, const SSL_METHOD *method)
701 int version = method->version;
703 if ((s->min_proto_version != 0 &&
704 version_cmp(s, version, s->min_proto_version) < 0) ||
705 ssl_security(s, SSL_SECOP_VERSION, 0, version, NULL) == 0)
706 return SSL_R_VERSION_TOO_LOW;
708 if (s->max_proto_version != 0 &&
709 version_cmp(s, version, s->max_proto_version) > 0)
710 return SSL_R_VERSION_TOO_HIGH;
712 if ((s->options & method->mask) != 0)
713 return SSL_R_UNSUPPORTED_PROTOCOL;
714 if ((method->flags & SSL_METHOD_NO_SUITEB) != 0 && tls1_suiteb(s))
715 return SSL_R_AT_LEAST_TLS_1_2_NEEDED_IN_SUITEB_MODE;
716 else if ((method->flags & SSL_METHOD_NO_FIPS) != 0 && FIPS_mode())
717 return SSL_R_AT_LEAST_TLS_1_0_NEEDED_IN_FIPS_MODE;
723 * ssl_version_supported - Check that the specified `version` is supported by
726 * @s: The SSL handle for the candidate method
727 * @version: Protocol version to test against
729 * Returns 1 when supported, otherwise 0
731 int ssl_version_supported(const SSL *s, int version)
733 const version_info *vent;
734 const version_info *table;
736 switch (s->method->version) {
738 /* Version should match method version for non-ANY method */
739 return version_cmp(s, version, s->version) == 0;
740 case TLS_ANY_VERSION:
741 table = tls_version_table;
743 case DTLS_ANY_VERSION:
744 table = dtls_version_table;
749 vent->version != 0 && version_cmp(s, version, vent->version) <= 0;
751 if (vent->cmeth != NULL &&
752 version_cmp(s, version, vent->version) == 0 &&
753 ssl_method_error(s, vent->cmeth()) == 0) {
761 * ssl_check_version_downgrade - In response to RFC7507 SCSV version
762 * fallback indication from a client check whether we're using the highest
763 * supported protocol version.
765 * @s server SSL handle.
767 * Returns 1 when using the highest enabled version, 0 otherwise.
769 int ssl_check_version_downgrade(SSL *s)
771 const version_info *vent;
772 const version_info *table;
775 * Check that the current protocol is the highest enabled version
776 * (according to s->ctx->method, as version negotiation may have changed
779 if (s->version == s->ctx->method->version)
783 * Apparently we're using a version-flexible SSL_METHOD (not at its
784 * highest protocol version).
786 if (s->ctx->method->version == TLS_method()->version)
787 table = tls_version_table;
788 else if (s->ctx->method->version == DTLS_method()->version)
789 table = dtls_version_table;
791 /* Unexpected state; fail closed. */
795 for (vent = table; vent->version != 0; ++vent) {
796 if (vent->smeth != NULL &&
797 ssl_method_error(s, vent->smeth()) == 0)
798 return s->version == vent->version;
804 * ssl_set_version_bound - set an upper or lower bound on the supported (D)TLS
805 * protocols, provided the initial (D)TLS method is version-flexible. This
806 * function sanity-checks the proposed value and makes sure the method is
807 * version-flexible, then sets the limit if all is well.
809 * @method_version: The version of the current SSL_METHOD.
810 * @version: the intended limit.
811 * @bound: pointer to limit to be updated.
813 * Returns 1 on success, 0 on failure.
815 int ssl_set_version_bound(int method_version, int version, int *bound)
823 * Restrict TLS methods to TLS protocol versions.
824 * Restrict DTLS methods to DTLS protocol versions.
825 * Note, DTLS version numbers are decreasing, use comparison macros.
827 * Note that for both lower-bounds we use explicit versions, not
828 * (D)TLS_MIN_VERSION. This is because we don't want to break user
829 * configurations. If the MIN (supported) version ever rises, the user's
830 * "floor" remains valid even if no longer available. We don't expect the
831 * MAX ceiling to ever get lower, so making that variable makes sense.
833 switch (method_version) {
836 * XXX For fixed version methods, should we always fail and not set any
837 * bounds, always succeed and not set any bounds, or set the bounds and
838 * arrange to fail later if they are not met? At present fixed-version
839 * methods are not subject to controls that disable individual protocol
844 case TLS_ANY_VERSION:
845 if (version < SSL3_VERSION || version > TLS_MAX_VERSION)
849 case DTLS_ANY_VERSION:
850 if (DTLS_VERSION_GT(version, DTLS_MAX_VERSION) ||
851 DTLS_VERSION_LT(version, DTLS1_VERSION))
861 * ssl_choose_server_version - Choose server (D)TLS version. Called when the
862 * client HELLO is received to select the final server protocol version and
863 * the version specific method.
865 * @s: server SSL handle.
867 * Returns 0 on success or an SSL error reason number on failure.
869 int ssl_choose_server_version(SSL *s)
872 * With version-flexible methods we have an initial state with:
874 * s->method->version == (D)TLS_ANY_VERSION,
875 * s->version == (D)TLS_MAX_VERSION.
877 * So we detect version-flexible methods via the method version, not the
880 int server_version = s->method->version;
881 int client_version = s->client_version;
882 const version_info *vent;
883 const version_info *table;
886 switch (server_version) {
888 if (version_cmp(s, client_version, s->version) < 0)
889 return SSL_R_WRONG_SSL_VERSION;
891 * If this SSL handle is not from a version flexible method we don't
892 * (and never did) check min/max FIPS or Suite B constraints. Hope
893 * that's OK. It is up to the caller to not choose fixed protocol
894 * versions they don't want. If not, then easy to fix, just return
895 * ssl_method_error(s, s->method)
898 case TLS_ANY_VERSION:
899 table = tls_version_table;
901 case DTLS_ANY_VERSION:
902 table = dtls_version_table;
906 for (vent = table; vent->version != 0; ++vent) {
907 const SSL_METHOD *method;
909 if (vent->smeth == NULL ||
910 version_cmp(s, client_version, vent->version) < 0)
912 method = vent->smeth();
913 if (ssl_method_error(s, method) == 0) {
914 s->version = vent->version;
920 return disabled ? SSL_R_UNSUPPORTED_PROTOCOL : SSL_R_VERSION_TOO_LOW;
924 * ssl_choose_client_version - Choose client (D)TLS version. Called when the
925 * server HELLO is received to select the final client protocol version and
926 * the version specific method.
928 * @s: client SSL handle.
929 * @version: The proposed version from the server's HELLO.
931 * Returns 0 on success or an SSL error reason number on failure.
933 int ssl_choose_client_version(SSL *s, int version)
935 const version_info *vent;
936 const version_info *table;
938 switch (s->method->version) {
940 if (version != s->version)
941 return SSL_R_WRONG_SSL_VERSION;
943 * If this SSL handle is not from a version flexible method we don't
944 * (and never did) check min/max, FIPS or Suite B constraints. Hope
945 * that's OK. It is up to the caller to not choose fixed protocol
946 * versions they don't want. If not, then easy to fix, just return
947 * ssl_method_error(s, s->method)
950 case TLS_ANY_VERSION:
951 table = tls_version_table;
953 case DTLS_ANY_VERSION:
954 table = dtls_version_table;
958 for (vent = table; vent->version != 0; ++vent) {
959 const SSL_METHOD *method;
962 if (version != vent->version)
964 if (vent->cmeth == NULL)
966 method = vent->cmeth();
967 err = ssl_method_error(s, method);
971 s->version = version;
975 return SSL_R_UNSUPPORTED_PROTOCOL;
979 * ssl_get_client_min_max_version - get minimum and maximum client version
980 * @s: The SSL connection
981 * @min_version: The minimum supported version
982 * @max_version: The maximum supported version
984 * Work out what version we should be using for the initial ClientHello if the
985 * version is initially (D)TLS_ANY_VERSION. We apply any explicit SSL_OP_NO_xxx
986 * options, the MinProtocol and MaxProtocol configuration commands, any Suite B
987 * or FIPS_mode() constraints and any floor imposed by the security level here,
988 * so we don't advertise the wrong protocol version to only reject the outcome later.
990 * Computing the right floor matters. If, e.g., TLS 1.0 and 1.2 are enabled,
991 * TLS 1.1 is disabled, but the security level, Suite-B and/or MinProtocol
992 * only allow TLS 1.2, we want to advertise TLS1.2, *not* TLS1.
994 * Returns 0 on success or an SSL error reason number on failure. On failure
995 * min_version and max_version will also be set to 0.
997 int ssl_get_client_min_max_version(const SSL *s, int *min_version, int *max_version)
1001 const SSL_METHOD *single = NULL;
1002 const SSL_METHOD *method;
1003 const version_info *table;
1004 const version_info *vent;
1006 switch (s->method->version) {
1009 * If this SSL handle is not from a version flexible method we don't
1010 * (and never did) check min/max FIPS or Suite B constraints. Hope
1011 * that's OK. It is up to the caller to not choose fixed protocol
1012 * versions they don't want. If not, then easy to fix, just return
1013 * ssl_method_error(s, s->method)
1015 *min_version = *max_version = s->version;
1017 case TLS_ANY_VERSION:
1018 table = tls_version_table;
1020 case DTLS_ANY_VERSION:
1021 table = dtls_version_table;
1026 * SSL_OP_NO_X disables all protocols above X *if* there are some protocols
1027 * below X enabled. This is required in order to maintain the "version
1028 * capability" vector contiguous. Any versions with a NULL client method
1029 * (protocol version client is disabled at compile-time) is also a "hole".
1031 * Our initial state is hole == 1, version == 0. That is, versions above
1032 * the first version in the method table are disabled (a "hole" above
1033 * the valid protocol entries) and we don't have a selected version yet.
1035 * Whenever "hole == 1", and we hit an enabled method, its version becomes
1036 * the selected version, and the method becomes a candidate "single"
1037 * method. We're no longer in a hole, so "hole" becomes 0.
1039 * If "hole == 0" and we hit an enabled method, then "single" is cleared,
1040 * as we support a contiguous range of at least two methods. If we hit
1041 * a disabled method, then hole becomes true again, but nothing else
1042 * changes yet, because all the remaining methods may be disabled too.
1043 * If we again hit an enabled method after the new hole, it becomes
1044 * selected, as we start from scratch.
1046 *min_version = version = 0;
1048 for (vent = table; vent->version != 0; ++vent) {
1050 * A table entry with a NULL client method is still a hole in the
1051 * "version capability" vector.
1053 if (vent->cmeth == NULL) {
1057 method = vent->cmeth();
1058 if (ssl_method_error(s, method) != 0) {
1062 *min_version = method->version;
1064 version = (single = method)->version;
1065 *min_version = version;
1070 *max_version = version;
1072 /* Fail if everything is disabled */
1074 return SSL_R_NO_PROTOCOLS_AVAILABLE;
1080 * ssl_set_client_hello_version - Work out what version we should be using for
1081 * the initial ClientHello.
1083 * @s: client SSL handle.
1085 * Returns 0 on success or an SSL error reason number on failure.
1087 int ssl_set_client_hello_version(SSL *s)
1089 int ver_min, ver_max, ret;
1091 ret = ssl_get_client_min_max_version(s, &ver_min, &ver_max);
1096 s->client_version = s->version = ver_max;