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openssl/ssl/statem/statem_lib.c
Dr. Stephen Henson d166ed8c11 check return values for EVP_Digest*() APIs 
Reviewed-by: Richard Levitte <levitte@openssl.org>
2016-07-15 14:09:05 +01:00

1098 lines
33 KiB
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/*
* Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/* ====================================================================
* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
* ECC cipher suite support in OpenSSL originally developed by
* SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
*/
#include <limits.h>
#include <string.h>
#include <stdio.h>
#include "../ssl_locl.h"
#include "statem_locl.h"
#include <openssl/buffer.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
/*
* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or
* SSL3_RT_CHANGE_CIPHER_SPEC)
*/
int ssl3_do_write(SSL *s, int type)
{
int ret;
ret = ssl3_write_bytes(s, type, &s->init_buf->data[s->init_off],
s->init_num);
if (ret < 0)
return (-1);
if (type == SSL3_RT_HANDSHAKE)
/*
* should not be done for 'Hello Request's, but in that case we'll
* ignore the result anyway
*/
if (!ssl3_finish_mac(s,
(unsigned char *)&s->init_buf->data[s->init_off],
ret))
return -1;
if (ret == s->init_num) {
if (s->msg_callback)
s->msg_callback(1, s->version, type, s->init_buf->data,
(size_t)(s->init_off + s->init_num), s,
s->msg_callback_arg);
return (1);
}
s->init_off += ret;
s->init_num -= ret;
return (0);
}
int tls_construct_finished(SSL *s, const char *sender, int slen)
{
unsigned char *p;
int i;
unsigned long l;
p = ssl_handshake_start(s);
i = s->method->ssl3_enc->final_finish_mac(s,
sender, slen,
s->s3->tmp.finish_md);
if (i <= 0)
return 0;
s->s3->tmp.finish_md_len = i;
memcpy(p, s->s3->tmp.finish_md, i);
l = i;
/*
* Copy the finished so we can use it for renegotiation checks
*/
if (!s->server) {
OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
memcpy(s->s3->previous_client_finished, s->s3->tmp.finish_md, i);
s->s3->previous_client_finished_len = i;
} else {
OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
memcpy(s->s3->previous_server_finished, s->s3->tmp.finish_md, i);
s->s3->previous_server_finished_len = i;
}
if (!ssl_set_handshake_header(s, SSL3_MT_FINISHED, l)) {
SSLerr(SSL_F_TLS_CONSTRUCT_FINISHED, ERR_R_INTERNAL_ERROR);
return 0;
}
return 1;
}
#ifndef OPENSSL_NO_NEXTPROTONEG
/*
* ssl3_take_mac calculates the Finished MAC for the handshakes messages seen
* to far.
*/
static void ssl3_take_mac(SSL *s)
{
const char *sender;
int slen;
/*
* If no new cipher setup return immediately: other functions will set
* the appropriate error.
*/
if (s->s3->tmp.new_cipher == NULL)
return;
if (!s->server) {
sender = s->method->ssl3_enc->server_finished_label;
slen = s->method->ssl3_enc->server_finished_label_len;
} else {
sender = s->method->ssl3_enc->client_finished_label;
slen = s->method->ssl3_enc->client_finished_label_len;
}
s->s3->tmp.peer_finish_md_len = s->method->ssl3_enc->final_finish_mac(s,
sender,
slen,
s->s3->tmp.peer_finish_md);
}
#endif
MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL *s, PACKET *pkt)
{
int al;
long remain;
remain = PACKET_remaining(pkt);
/*
* 'Change Cipher Spec' is just a single byte, which should already have
* been consumed by ssl_get_message() so there should be no bytes left,
* unless we're using DTLS1_BAD_VER, which has an extra 2 bytes
*/
if (SSL_IS_DTLS(s)) {
if ((s->version == DTLS1_BAD_VER
&& remain != DTLS1_CCS_HEADER_LENGTH + 1)
|| (s->version != DTLS1_BAD_VER
&& remain != DTLS1_CCS_HEADER_LENGTH - 1)) {
al = SSL_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC,
SSL_R_BAD_CHANGE_CIPHER_SPEC);
goto f_err;
}
} else {
if (remain != 0) {
al = SSL_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC,
SSL_R_BAD_CHANGE_CIPHER_SPEC);
goto f_err;
}
}
/* Check we have a cipher to change to */
if (s->s3->tmp.new_cipher == NULL) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC, SSL_R_CCS_RECEIVED_EARLY);
goto f_err;
}
s->s3->change_cipher_spec = 1;
if (!ssl3_do_change_cipher_spec(s)) {
al = SSL_AD_INTERNAL_ERROR;
SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
goto f_err;
}
if (SSL_IS_DTLS(s)) {
dtls1_reset_seq_numbers(s, SSL3_CC_READ);
if (s->version == DTLS1_BAD_VER)
s->d1->handshake_read_seq++;
#ifndef OPENSSL_NO_SCTP
/*
* Remember that a CCS has been received, so that an old key of
* SCTP-Auth can be deleted when a CCS is sent. Will be ignored if no
* SCTP is used
*/
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_AUTH_CCS_RCVD, 1, NULL);
#endif
}
return MSG_PROCESS_CONTINUE_READING;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
ossl_statem_set_error(s);
return MSG_PROCESS_ERROR;
}
MSG_PROCESS_RETURN tls_process_finished(SSL *s, PACKET *pkt)
{
int al, i;
/* If this occurs, we have missed a message */
if (!s->s3->change_cipher_spec) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_GOT_A_FIN_BEFORE_A_CCS);
goto f_err;
}
s->s3->change_cipher_spec = 0;
i = s->s3->tmp.peer_finish_md_len;
if ((unsigned long)i != PACKET_remaining(pkt)) {
al = SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_BAD_DIGEST_LENGTH);
goto f_err;
}
if (CRYPTO_memcmp(PACKET_data(pkt), s->s3->tmp.peer_finish_md, i) != 0) {
al = SSL_AD_DECRYPT_ERROR;
SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_DIGEST_CHECK_FAILED);
goto f_err;
}
/*
* Copy the finished so we can use it for renegotiation checks
*/
if (s->server) {
OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
memcpy(s->s3->previous_client_finished, s->s3->tmp.peer_finish_md, i);
s->s3->previous_client_finished_len = i;
} else {
OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
memcpy(s->s3->previous_server_finished, s->s3->tmp.peer_finish_md, i);
s->s3->previous_server_finished_len = i;
}
return MSG_PROCESS_FINISHED_READING;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
ossl_statem_set_error(s);
return MSG_PROCESS_ERROR;
}
int tls_construct_change_cipher_spec(SSL *s)
{
unsigned char *p;
p = (unsigned char *)s->init_buf->data;
*p = SSL3_MT_CCS;
s->init_num = 1;
s->init_off = 0;
return 1;
}
unsigned long ssl3_output_cert_chain(SSL *s, CERT_PKEY *cpk)
{
unsigned char *p;
unsigned long l = 3 + SSL_HM_HEADER_LENGTH(s);
if (!ssl_add_cert_chain(s, cpk, &l))
return 0;
l -= 3 + SSL_HM_HEADER_LENGTH(s);
p = ssl_handshake_start(s);
l2n3(l, p);
l += 3;
if (!ssl_set_handshake_header(s, SSL3_MT_CERTIFICATE, l)) {
SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN, ERR_R_INTERNAL_ERROR);
return 0;
}
return l + SSL_HM_HEADER_LENGTH(s);
}
WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst)
{
void (*cb) (const SSL *ssl, int type, int val) = NULL;
#ifndef OPENSSL_NO_SCTP
if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
WORK_STATE ret;
ret = dtls_wait_for_dry(s);
if (ret != WORK_FINISHED_CONTINUE)
return ret;
}
#endif
/* clean a few things up */
ssl3_cleanup_key_block(s);
if (!SSL_IS_DTLS(s)) {
/*
* We don't do this in DTLS because we may still need the init_buf
* in case there are any unexpected retransmits
*/
BUF_MEM_free(s->init_buf);
s->init_buf = NULL;
}
ssl_free_wbio_buffer(s);
s->init_num = 0;
if (!s->server || s->renegotiate == 2) {
/* skipped if we just sent a HelloRequest */
s->renegotiate = 0;
s->new_session = 0;
if (s->server) {
ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
s->ctx->stats.sess_accept_good++;
s->handshake_func = ossl_statem_accept;
} else {
ssl_update_cache(s, SSL_SESS_CACHE_CLIENT);
if (s->hit)
s->ctx->stats.sess_hit++;
s->handshake_func = ossl_statem_connect;
s->ctx->stats.sess_connect_good++;
}
if (s->info_callback != NULL)
cb = s->info_callback;
else if (s->ctx->info_callback != NULL)
cb = s->ctx->info_callback;
if (cb != NULL)
cb(s, SSL_CB_HANDSHAKE_DONE, 1);
if (SSL_IS_DTLS(s)) {
/* done with handshaking */
s->d1->handshake_read_seq = 0;
s->d1->handshake_write_seq = 0;
s->d1->next_handshake_write_seq = 0;
}
}
return WORK_FINISHED_STOP;
}
int tls_get_message_header(SSL *s, int *mt)
{
/* s->init_num < SSL3_HM_HEADER_LENGTH */
int skip_message, i, recvd_type, al;
unsigned char *p;
unsigned long l;
p = (unsigned char *)s->init_buf->data;
do {
while (s->init_num < SSL3_HM_HEADER_LENGTH) {
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &recvd_type,
&p[s->init_num], SSL3_HM_HEADER_LENGTH - s->init_num, 0);
if (i <= 0) {
s->rwstate = SSL_READING;
return 0;
}
if (recvd_type == SSL3_RT_CHANGE_CIPHER_SPEC) {
/*
* A ChangeCipherSpec must be a single byte and may not occur
* in the middle of a handshake message.
*/
if (s->init_num != 0 || i != 1 || p[0] != SSL3_MT_CCS) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER,
SSL_R_BAD_CHANGE_CIPHER_SPEC);
goto f_err;
}
s->s3->tmp.message_type = *mt = SSL3_MT_CHANGE_CIPHER_SPEC;
s->init_num = i - 1;
s->s3->tmp.message_size = i;
return 1;
} else if (recvd_type != SSL3_RT_HANDSHAKE) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, SSL_R_CCS_RECEIVED_EARLY);
goto f_err;
}
s->init_num += i;
}
skip_message = 0;
if (!s->server)
if (p[0] == SSL3_MT_HELLO_REQUEST)
/*
* The server may always send 'Hello Request' messages --
* we are doing a handshake anyway now, so ignore them if
* their format is correct. Does not count for 'Finished'
* MAC.
*/
if (p[1] == 0 && p[2] == 0 && p[3] == 0) {
s->init_num = 0;
skip_message = 1;
if (s->msg_callback)
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
p, SSL3_HM_HEADER_LENGTH, s,
s->msg_callback_arg);
}
} while (skip_message);
/* s->init_num == SSL3_HM_HEADER_LENGTH */
*mt = *p;
s->s3->tmp.message_type = *(p++);
if(RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
/*
* Only happens with SSLv3+ in an SSLv2 backward compatible
* ClientHello
*/
/*
* Total message size is the remaining record bytes to read
* plus the SSL3_HM_HEADER_LENGTH bytes that we already read
*/
l = RECORD_LAYER_get_rrec_length(&s->rlayer)
+ SSL3_HM_HEADER_LENGTH;
if (l && !BUF_MEM_grow_clean(s->init_buf, (int)l)) {
SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, ERR_R_BUF_LIB);
goto err;
}
s->s3->tmp.message_size = l;
s->init_msg = s->init_buf->data;
s->init_num = SSL3_HM_HEADER_LENGTH;
} else {
n2l3(p, l);
/* BUF_MEM_grow takes an 'int' parameter */
if (l > (INT_MAX - SSL3_HM_HEADER_LENGTH)) {
al = SSL_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, SSL_R_EXCESSIVE_MESSAGE_SIZE);
goto f_err;
}
if (l && !BUF_MEM_grow_clean(s->init_buf,
(int)l + SSL3_HM_HEADER_LENGTH)) {
SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, ERR_R_BUF_LIB);
goto err;
}
s->s3->tmp.message_size = l;
s->init_msg = s->init_buf->data + SSL3_HM_HEADER_LENGTH;
s->init_num = 0;
}
return 1;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
err:
return 0;
}
int tls_get_message_body(SSL *s, unsigned long *len)
{
long n;
unsigned char *p;
int i;
if (s->s3->tmp.message_type == SSL3_MT_CHANGE_CIPHER_SPEC) {
/* We've already read everything in */
*len = (unsigned long)s->init_num;
return 1;
}
p = s->init_msg;
n = s->s3->tmp.message_size - s->init_num;
while (n > 0) {
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
&p[s->init_num], n, 0);
if (i <= 0) {
s->rwstate = SSL_READING;
*len = 0;
return 0;
}
s->init_num += i;
n -= i;
}
#ifndef OPENSSL_NO_NEXTPROTONEG
/*
* If receiving Finished, record MAC of prior handshake messages for
* Finished verification.
*/
if (*s->init_buf->data == SSL3_MT_FINISHED)
ssl3_take_mac(s);
#endif
/* Feed this message into MAC computation. */
if(RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
s->init_num)) {
SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_EVP_LIB);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
*len = 0;
return 0;
}
if (s->msg_callback)
s->msg_callback(0, SSL2_VERSION, 0, s->init_buf->data,
(size_t)s->init_num, s, s->msg_callback_arg);
} else {
if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
s->init_num + SSL3_HM_HEADER_LENGTH)) {
SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_EVP_LIB);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
*len = 0;
return 0;
}
if (s->msg_callback)
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data,
(size_t)s->init_num + SSL3_HM_HEADER_LENGTH, s,
s->msg_callback_arg);
}
/*
* init_num should never be negative...should probably be declared
* unsigned
*/
if (s->init_num < 0) {
SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_INTERNAL_ERROR);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
*len = 0;
return 0;
}
*len = (unsigned long)s->init_num;
return 1;
}
int ssl_cert_type(X509 *x, EVP_PKEY *pk)
{
if (pk == NULL &&
(pk = X509_get0_pubkey(x)) == NULL)
return -1;
switch (EVP_PKEY_id(pk)) {
default:
return -1;
case EVP_PKEY_RSA:
return SSL_PKEY_RSA_ENC;
case EVP_PKEY_DSA:
return SSL_PKEY_DSA_SIGN;
#ifndef OPENSSL_NO_EC
case EVP_PKEY_EC:
return SSL_PKEY_ECC;
#endif
#ifndef OPENSSL_NO_GOST
case NID_id_GostR3410_2001:
return SSL_PKEY_GOST01;
case NID_id_GostR3410_2012_256:
return SSL_PKEY_GOST12_256;
case NID_id_GostR3410_2012_512:
return SSL_PKEY_GOST12_512;
#endif
}
}
int ssl_verify_alarm_type(long type)
{
int al;
switch (type) {
case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
case X509_V_ERR_UNABLE_TO_GET_CRL:
case X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER:
al = SSL_AD_UNKNOWN_CA;
break;
case X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE:
case X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE:
case X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY:
case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
case X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD:
case X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD:
case X509_V_ERR_CERT_NOT_YET_VALID:
case X509_V_ERR_CRL_NOT_YET_VALID:
case X509_V_ERR_CERT_UNTRUSTED:
case X509_V_ERR_CERT_REJECTED:
case X509_V_ERR_HOSTNAME_MISMATCH:
case X509_V_ERR_EMAIL_MISMATCH:
case X509_V_ERR_IP_ADDRESS_MISMATCH:
case X509_V_ERR_DANE_NO_MATCH:
case X509_V_ERR_EE_KEY_TOO_SMALL:
case X509_V_ERR_CA_KEY_TOO_SMALL:
case X509_V_ERR_CA_MD_TOO_WEAK:
al = SSL_AD_BAD_CERTIFICATE;
break;
case X509_V_ERR_CERT_SIGNATURE_FAILURE:
case X509_V_ERR_CRL_SIGNATURE_FAILURE:
al = SSL_AD_DECRYPT_ERROR;
break;
case X509_V_ERR_CERT_HAS_EXPIRED:
case X509_V_ERR_CRL_HAS_EXPIRED:
al = SSL_AD_CERTIFICATE_EXPIRED;
break;
case X509_V_ERR_CERT_REVOKED:
al = SSL_AD_CERTIFICATE_REVOKED;
break;
case X509_V_ERR_UNSPECIFIED:
case X509_V_ERR_OUT_OF_MEM:
case X509_V_ERR_INVALID_CALL:
case X509_V_ERR_STORE_LOOKUP:
al = SSL_AD_INTERNAL_ERROR;
break;
case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT:
case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN:
case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY:
case X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE:
case X509_V_ERR_CERT_CHAIN_TOO_LONG:
case X509_V_ERR_PATH_LENGTH_EXCEEDED:
case X509_V_ERR_INVALID_CA:
al = SSL_AD_UNKNOWN_CA;
break;
case X509_V_ERR_APPLICATION_VERIFICATION:
al = SSL_AD_HANDSHAKE_FAILURE;
break;
case X509_V_ERR_INVALID_PURPOSE:
al = SSL_AD_UNSUPPORTED_CERTIFICATE;
break;
default:
al = SSL_AD_CERTIFICATE_UNKNOWN;
break;
}
return (al);
}
int ssl_allow_compression(SSL *s)
{
if (s->options & SSL_OP_NO_COMPRESSION)
return 0;
return ssl_security(s, SSL_SECOP_COMPRESSION, 0, 0, NULL);
}
static int version_cmp(const SSL *s, int a, int b)
{
int dtls = SSL_IS_DTLS(s);
if (a == b)
return 0;
if (!dtls)
return a < b ? -1 : 1;
return DTLS_VERSION_LT(a, b) ? -1 : 1;
}
typedef struct {
int version;
const SSL_METHOD *(*cmeth)(void);
const SSL_METHOD *(*smeth)(void);
} version_info;
#if TLS_MAX_VERSION != TLS1_2_VERSION
# error Code needs update for TLS_method() support beyond TLS1_2_VERSION.
#endif
static const version_info tls_version_table[] = {
#ifndef OPENSSL_NO_TLS1_2
{ TLS1_2_VERSION, tlsv1_2_client_method, tlsv1_2_server_method },
#else
{ TLS1_2_VERSION, NULL, NULL },
#endif
#ifndef OPENSSL_NO_TLS1_1
{ TLS1_1_VERSION, tlsv1_1_client_method, tlsv1_1_server_method },
#else
{ TLS1_1_VERSION, NULL, NULL },
#endif
#ifndef OPENSSL_NO_TLS1
{ TLS1_VERSION, tlsv1_client_method, tlsv1_server_method },
#else
{ TLS1_VERSION, NULL, NULL },
#endif
#ifndef OPENSSL_NO_SSL3
{ SSL3_VERSION, sslv3_client_method, sslv3_server_method },
#else
{ SSL3_VERSION, NULL, NULL },
#endif
{ 0, NULL, NULL },
};
#if DTLS_MAX_VERSION != DTLS1_2_VERSION
# error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
#endif
static const version_info dtls_version_table[] = {
#ifndef OPENSSL_NO_DTLS1_2
{ DTLS1_2_VERSION, dtlsv1_2_client_method, dtlsv1_2_server_method },
#else
{ DTLS1_2_VERSION, NULL, NULL },
#endif
#ifndef OPENSSL_NO_DTLS1
{ DTLS1_VERSION, dtlsv1_client_method, dtlsv1_server_method },
#else
{ DTLS1_VERSION, NULL, NULL },
#endif
{ 0, NULL, NULL },
};
/*
* ssl_method_error - Check whether an SSL_METHOD is enabled.
*
* @s: The SSL handle for the candidate method
* @method: the intended method.
*
* Returns 0 on success, or an SSL error reason on failure.
*/
static int ssl_method_error(const SSL *s, const SSL_METHOD *method)
{
int version = method->version;
if ((s->min_proto_version != 0 &&
version_cmp(s, version, s->min_proto_version) < 0) ||
ssl_security(s, SSL_SECOP_VERSION, 0, version, NULL) == 0)
return SSL_R_VERSION_TOO_LOW;
if (s->max_proto_version != 0 &&
version_cmp(s, version, s->max_proto_version) > 0)
return SSL_R_VERSION_TOO_HIGH;
if ((s->options & method->mask) != 0)
return SSL_R_UNSUPPORTED_PROTOCOL;
if ((method->flags & SSL_METHOD_NO_SUITEB) != 0 && tls1_suiteb(s))
return SSL_R_AT_LEAST_TLS_1_2_NEEDED_IN_SUITEB_MODE;
else if ((method->flags & SSL_METHOD_NO_FIPS) != 0 && FIPS_mode())
return SSL_R_AT_LEAST_TLS_1_0_NEEDED_IN_FIPS_MODE;
return 0;
}
/*
* ssl_version_supported - Check that the specified `version` is supported by
* `SSL *` instance
*
* @s: The SSL handle for the candidate method
* @version: Protocol version to test against
*
* Returns 1 when supported, otherwise 0
*/
int ssl_version_supported(const SSL *s, int version)
{
const version_info *vent;
const version_info *table;
switch (s->method->version) {
default:
/* Version should match method version for non-ANY method */
return version_cmp(s, version, s->version) == 0;
case TLS_ANY_VERSION:
table = tls_version_table;
break;
case DTLS_ANY_VERSION:
table = dtls_version_table;
break;
}
for (vent = table;
vent->version != 0 && version_cmp(s, version, vent->version) <= 0;
++vent) {
if (vent->cmeth != NULL &&
version_cmp(s, version, vent->version) == 0 &&
ssl_method_error(s, vent->cmeth()) == 0) {
return 1;
}
}
return 0;
}
/*
* ssl_check_version_downgrade - In response to RFC7507 SCSV version
* fallback indication from a client check whether we're using the highest
* supported protocol version.
*
* @s server SSL handle.
*
* Returns 1 when using the highest enabled version, 0 otherwise.
*/
int ssl_check_version_downgrade(SSL *s)
{
const version_info *vent;
const version_info *table;
/*
* Check that the current protocol is the highest enabled version
* (according to s->ctx->method, as version negotiation may have changed
* s->method).
*/
if (s->version == s->ctx->method->version)
return 1;
/*
* Apparently we're using a version-flexible SSL_METHOD (not at its
* highest protocol version).
*/
if (s->ctx->method->version == TLS_method()->version)
table = tls_version_table;
else if (s->ctx->method->version == DTLS_method()->version)
table = dtls_version_table;
else {
/* Unexpected state; fail closed. */
return 0;
}
for (vent = table; vent->version != 0; ++vent) {
if (vent->smeth != NULL &&
ssl_method_error(s, vent->smeth()) == 0)
return s->version == vent->version;
}
return 0;
}
/*
* ssl_set_version_bound - set an upper or lower bound on the supported (D)TLS
* protocols, provided the initial (D)TLS method is version-flexible. This
* function sanity-checks the proposed value and makes sure the method is
* version-flexible, then sets the limit if all is well.
*
* @method_version: The version of the current SSL_METHOD.
* @version: the intended limit.
* @bound: pointer to limit to be updated.
*
* Returns 1 on success, 0 on failure.
*/
int ssl_set_version_bound(int method_version, int version, int *bound)
{
if (version == 0) {
*bound = version;
return 1;
}
/*-
* Restrict TLS methods to TLS protocol versions.
* Restrict DTLS methods to DTLS protocol versions.
* Note, DTLS version numbers are decreasing, use comparison macros.
*
* Note that for both lower-bounds we use explicit versions, not
* (D)TLS_MIN_VERSION. This is because we don't want to break user
* configurations. If the MIN (supported) version ever rises, the user's
* "floor" remains valid even if no longer available. We don't expect the
* MAX ceiling to ever get lower, so making that variable makes sense.
*/
switch (method_version) {
default:
/*
* XXX For fixed version methods, should we always fail and not set any
* bounds, always succeed and not set any bounds, or set the bounds and
* arrange to fail later if they are not met? At present fixed-version
* methods are not subject to controls that disable individual protocol
* versions.
*/
return 0;
case TLS_ANY_VERSION:
if (version < SSL3_VERSION || version > TLS_MAX_VERSION)
return 0;
break;
case DTLS_ANY_VERSION:
if (DTLS_VERSION_GT(version, DTLS_MAX_VERSION) ||
DTLS_VERSION_LT(version, DTLS1_VERSION))
return 0;
break;
}
*bound = version;
return 1;
}
/*
* ssl_choose_server_version - Choose server (D)TLS version. Called when the
* client HELLO is received to select the final server protocol version and
* the version specific method.
*
* @s: server SSL handle.
*
* Returns 0 on success or an SSL error reason number on failure.
*/
int ssl_choose_server_version(SSL *s)
{
/*-
* With version-flexible methods we have an initial state with:
*
* s->method->version == (D)TLS_ANY_VERSION,
* s->version == (D)TLS_MAX_VERSION.
*
* So we detect version-flexible methods via the method version, not the
* handle version.
*/
int server_version = s->method->version;
int client_version = s->client_version;
const version_info *vent;
const version_info *table;
int disabled = 0;
switch (server_version) {
default:
if (version_cmp(s, client_version, s->version) < 0)
return SSL_R_WRONG_SSL_VERSION;
/*
* If this SSL handle is not from a version flexible method we don't
* (and never did) check min/max FIPS or Suite B constraints. Hope
* that's OK. It is up to the caller to not choose fixed protocol
* versions they don't want. If not, then easy to fix, just return
* ssl_method_error(s, s->method)
*/
return 0;
case TLS_ANY_VERSION:
table = tls_version_table;
break;
case DTLS_ANY_VERSION:
table = dtls_version_table;
break;
}
for (vent = table; vent->version != 0; ++vent) {
const SSL_METHOD *method;
if (vent->smeth == NULL ||
version_cmp(s, client_version, vent->version) < 0)
continue;
method = vent->smeth();
if (ssl_method_error(s, method) == 0) {
s->version = vent->version;
s->method = method;
return 0;
}
disabled = 1;
}
return disabled ? SSL_R_UNSUPPORTED_PROTOCOL : SSL_R_VERSION_TOO_LOW;
}
/*
* ssl_choose_client_version - Choose client (D)TLS version. Called when the
* server HELLO is received to select the final client protocol version and
* the version specific method.
*
* @s: client SSL handle.
* @version: The proposed version from the server's HELLO.
*
* Returns 0 on success or an SSL error reason number on failure.
*/
int ssl_choose_client_version(SSL *s, int version)
{
const version_info *vent;
const version_info *table;
switch (s->method->version) {
default:
if (version != s->version)
return SSL_R_WRONG_SSL_VERSION;
/*
* If this SSL handle is not from a version flexible method we don't
* (and never did) check min/max, FIPS or Suite B constraints. Hope
* that's OK. It is up to the caller to not choose fixed protocol
* versions they don't want. If not, then easy to fix, just return
* ssl_method_error(s, s->method)
*/
return 0;
case TLS_ANY_VERSION:
table = tls_version_table;
break;
case DTLS_ANY_VERSION:
table = dtls_version_table;
break;
}
for (vent = table; vent->version != 0; ++vent) {
const SSL_METHOD *method;
int err;
if (version != vent->version)
continue;
if (vent->cmeth == NULL)
break;
method = vent->cmeth();
err = ssl_method_error(s, method);
if (err != 0)
return err;
s->method = method;
s->version = version;
return 0;
}
return SSL_R_UNSUPPORTED_PROTOCOL;
}
/*
* ssl_get_client_min_max_version - get minimum and maximum client version
* @s: The SSL connection
* @min_version: The minimum supported version
* @max_version: The maximum supported version
*
* Work out what version we should be using for the initial ClientHello if the
* version is initially (D)TLS_ANY_VERSION. We apply any explicit SSL_OP_NO_xxx
* options, the MinProtocol and MaxProtocol configuration commands, any Suite B
* or FIPS_mode() constraints and any floor imposed by the security level here,
* so we don't advertise the wrong protocol version to only reject the outcome later.
*
* Computing the right floor matters. If, e.g., TLS 1.0 and 1.2 are enabled,
* TLS 1.1 is disabled, but the security level, Suite-B and/or MinProtocol
* only allow TLS 1.2, we want to advertise TLS1.2, *not* TLS1.
*
* Returns 0 on success or an SSL error reason number on failure. On failure
* min_version and max_version will also be set to 0.
*/
int ssl_get_client_min_max_version(const SSL *s, int *min_version, int *max_version)
{
int version;
int hole;
const SSL_METHOD *single = NULL;
const SSL_METHOD *method;
const version_info *table;
const version_info *vent;
switch (s->method->version) {
default:
/*
* If this SSL handle is not from a version flexible method we don't
* (and never did) check min/max FIPS or Suite B constraints. Hope
* that's OK. It is up to the caller to not choose fixed protocol
* versions they don't want. If not, then easy to fix, just return
* ssl_method_error(s, s->method)
*/
*min_version = *max_version = s->version;
return 0;
case TLS_ANY_VERSION:
table = tls_version_table;
break;
case DTLS_ANY_VERSION:
table = dtls_version_table;
break;
}
/*
* SSL_OP_NO_X disables all protocols above X *if* there are some protocols
* below X enabled. This is required in order to maintain the "version
* capability" vector contiguous. Any versions with a NULL client method
* (protocol version client is disabled at compile-time) is also a "hole".
*
* Our initial state is hole == 1, version == 0. That is, versions above
* the first version in the method table are disabled (a "hole" above
* the valid protocol entries) and we don't have a selected version yet.
*
* Whenever "hole == 1", and we hit an enabled method, its version becomes
* the selected version, and the method becomes a candidate "single"
* method. We're no longer in a hole, so "hole" becomes 0.
*
* If "hole == 0" and we hit an enabled method, then "single" is cleared,
* as we support a contiguous range of at least two methods. If we hit
* a disabled method, then hole becomes true again, but nothing else
* changes yet, because all the remaining methods may be disabled too.
* If we again hit an enabled method after the new hole, it becomes
* selected, as we start from scratch.
*/
*min_version = version = 0;
hole = 1;
for (vent = table; vent->version != 0; ++vent) {
/*
* A table entry with a NULL client method is still a hole in the
* "version capability" vector.
*/
if (vent->cmeth == NULL) {
hole = 1;
continue;
}
method = vent->cmeth();
if (ssl_method_error(s, method) != 0) {
hole = 1;
} else if (!hole) {
single = NULL;
*min_version = method->version;
} else {
version = (single = method)->version;
*min_version = version;
hole = 0;
}
}
*max_version = version;
/* Fail if everything is disabled */
if (version == 0)
return SSL_R_NO_PROTOCOLS_AVAILABLE;
return 0;
}
/*
* ssl_set_client_hello_version - Work out what version we should be using for
* the initial ClientHello.
*
* @s: client SSL handle.
*
* Returns 0 on success or an SSL error reason number on failure.
*/
int ssl_set_client_hello_version(SSL *s)
{
int ver_min, ver_max, ret;
ret = ssl_get_client_min_max_version(s, &ver_min, &ver_max);
if (ret != 0)
return ret;
s->client_version = s->version = ver_max;
return 0;
}
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