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/* Copyright (c) 2017, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/ssl.h>
#include <assert.h>
#include <openssl/bytestring.h>
#include <openssl/err.h>
#include "internal.h"
#include "../crypto/internal.h"
namespace bssl {
int ssl_protocol_version_from_wire(uint16_t *out, uint16_t version) {
switch (version) {
case SSL3_VERSION:
case TLS1_VERSION:
case TLS1_1_VERSION:
case TLS1_2_VERSION:
*out = version;
return 1;
case TLS1_3_DRAFT_VERSION:
case TLS1_3_EXPERIMENT_VERSION:
case TLS1_3_RECORD_TYPE_EXPERIMENT_VERSION:
*out = TLS1_3_VERSION;
return 1;
case DTLS1_VERSION:
/* DTLS 1.0 is analogous to TLS 1.1, not TLS 1.0. */
*out = TLS1_1_VERSION;
return 1;
case DTLS1_2_VERSION:
*out = TLS1_2_VERSION;
return 1;
default:
return 0;
}
}
/* The follow arrays are the supported versions for TLS and DTLS, in order of
* decreasing preference. */
static const uint16_t kTLSVersions[] = {
TLS1_3_EXPERIMENT_VERSION,
TLS1_3_RECORD_TYPE_EXPERIMENT_VERSION,
TLS1_3_DRAFT_VERSION,
TLS1_2_VERSION,
TLS1_1_VERSION,
TLS1_VERSION,
SSL3_VERSION,
};
static const uint16_t kDTLSVersions[] = {
DTLS1_2_VERSION,
DTLS1_VERSION,
};
static void get_method_versions(const SSL_PROTOCOL_METHOD *method,
const uint16_t **out, size_t *out_num) {
if (method->is_dtls) {
*out = kDTLSVersions;
*out_num = OPENSSL_ARRAY_SIZE(kDTLSVersions);
} else {
*out = kTLSVersions;
*out_num = OPENSSL_ARRAY_SIZE(kTLSVersions);
}
}
static int method_supports_version(const SSL_PROTOCOL_METHOD *method,
uint16_t version) {
const uint16_t *versions;
size_t num_versions;
get_method_versions(method, &versions, &num_versions);
for (size_t i = 0; i < num_versions; i++) {
if (versions[i] == version) {
return 1;
}
}
return 0;
}
static int set_version_bound(const SSL_PROTOCOL_METHOD *method, uint16_t *out,
uint16_t version) {
/* The public API uses wire versions, except we use |TLS1_3_VERSION|
* everywhere to refer to any draft TLS 1.3 versions. In this direction, we
* map it to some representative TLS 1.3 draft version. */
if (version == TLS1_3_DRAFT_VERSION ||
version == TLS1_3_EXPERIMENT_VERSION ||
version == TLS1_3_RECORD_TYPE_EXPERIMENT_VERSION) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_SSL_VERSION);
return 0;
}
if (version == TLS1_3_VERSION) {
version = TLS1_3_DRAFT_VERSION;
}
if (!method_supports_version(method, version) ||
!ssl_protocol_version_from_wire(out, version)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_SSL_VERSION);
return 0;
}
return 1;
}
static int set_min_version(const SSL_PROTOCOL_METHOD *method, uint16_t *out,
uint16_t version) {
/* Zero is interpreted as the default minimum version. */
if (version == 0) {
/* SSL 3.0 is disabled by default and TLS 1.0 does not exist in DTLS. */
*out = method->is_dtls ? TLS1_1_VERSION : TLS1_VERSION;
return 1;
}
return set_version_bound(method, out, version);
}
static int set_max_version(const SSL_PROTOCOL_METHOD *method, uint16_t *out,
uint16_t version) {
/* Zero is interpreted as the default maximum version. */
if (version == 0) {
*out = TLS1_2_VERSION;
return 1;
}
return set_version_bound(method, out, version);
}
const struct {
uint16_t version;
uint32_t flag;
} kProtocolVersions[] = {
{SSL3_VERSION, SSL_OP_NO_SSLv3},
{TLS1_VERSION, SSL_OP_NO_TLSv1},
{TLS1_1_VERSION, SSL_OP_NO_TLSv1_1},
{TLS1_2_VERSION, SSL_OP_NO_TLSv1_2},
{TLS1_3_VERSION, SSL_OP_NO_TLSv1_3},
};
int ssl_get_version_range(const SSL *ssl, uint16_t *out_min_version,
uint16_t *out_max_version) {
/* For historical reasons, |SSL_OP_NO_DTLSv1| aliases |SSL_OP_NO_TLSv1|, but
* DTLS 1.0 should be mapped to TLS 1.1. */
uint32_t options = ssl->options;
if (SSL_is_dtls(ssl)) {
options &= ~SSL_OP_NO_TLSv1_1;
if (options & SSL_OP_NO_DTLSv1) {
options |= SSL_OP_NO_TLSv1_1;
}
}
uint16_t min_version = ssl->conf_min_version;
uint16_t max_version = ssl->conf_max_version;
/* OpenSSL's API for controlling versions entails blacklisting individual
* protocols. This has two problems. First, on the client, the protocol can
* only express a contiguous range of versions. Second, a library consumer
* trying to set a maximum version cannot disable protocol versions that get
* added in a future version of the library.
*
* To account for both of these, OpenSSL interprets the client-side bitmask
* as a min/max range by picking the lowest contiguous non-empty range of
* enabled protocols. Note that this means it is impossible to set a maximum
* version of the higest supported TLS version in a future-proof way. */
int any_enabled = 0;
for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kProtocolVersions); i++) {
/* Only look at the versions already enabled. */
if (min_version > kProtocolVersions[i].version) {
continue;
}
if (max_version < kProtocolVersions[i].version) {
break;
}
if (!(options & kProtocolVersions[i].flag)) {
/* The minimum version is the first enabled version. */
if (!any_enabled) {
any_enabled = 1;
min_version = kProtocolVersions[i].version;
}
continue;
}
/* If there is a disabled version after the first enabled one, all versions
* after it are implicitly disabled. */
if (any_enabled) {
max_version = kProtocolVersions[i-1].version;
break;
}
}
if (!any_enabled) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SUPPORTED_VERSIONS_ENABLED);
return 0;
}
*out_min_version = min_version;
*out_max_version = max_version;
return 1;
}
static uint16_t ssl_version(const SSL *ssl) {
/* In early data, we report the predicted version. */
if (SSL_in_early_data(ssl) && !ssl->server) {
return ssl->s3->hs->early_session->ssl_version;
}
return ssl->version;
}
static const char *ssl_version_to_string(uint16_t version) {
switch (version) {
/* Report TLS 1.3 draft version as TLS 1.3 in the public API. */
case TLS1_3_DRAFT_VERSION:
case TLS1_3_EXPERIMENT_VERSION:
case TLS1_3_RECORD_TYPE_EXPERIMENT_VERSION:
return "TLSv1.3";
case TLS1_2_VERSION:
return "TLSv1.2";
case TLS1_1_VERSION:
return "TLSv1.1";
case TLS1_VERSION:
return "TLSv1";
case SSL3_VERSION:
return "SSLv3";
case DTLS1_VERSION:
return "DTLSv1";
case DTLS1_2_VERSION:
return "DTLSv1.2";
default:
return "unknown";
}
}
uint16_t ssl3_protocol_version(const SSL *ssl) {
assert(ssl->s3->have_version);
uint16_t version;
if (!ssl_protocol_version_from_wire(&version, ssl->version)) {
/* |ssl->version| will always be set to a valid version. */
assert(0);
return 0;
}
return version;
}
int ssl_supports_version(SSL_HANDSHAKE *hs, uint16_t version) {
SSL *const ssl = hs->ssl;
/* As a client, only allow the configured TLS 1.3 variant. As a server,
* support all TLS 1.3 variants as long as tls13_variant is set to a
* non-default value. */
if (ssl->server) {
if (ssl->tls13_variant == tls13_default &&
(version == TLS1_3_EXPERIMENT_VERSION ||
version == TLS1_3_RECORD_TYPE_EXPERIMENT_VERSION)) {
return 0;
}
} else {
if ((ssl->tls13_variant != tls13_experiment &&
ssl->tls13_variant != tls13_no_session_id_experiment &&
version == TLS1_3_EXPERIMENT_VERSION) ||
(ssl->tls13_variant != tls13_record_type_experiment &&
version == TLS1_3_RECORD_TYPE_EXPERIMENT_VERSION) ||
(ssl->tls13_variant != tls13_default &&
version == TLS1_3_DRAFT_VERSION)) {
return 0;
}
}
uint16_t protocol_version;
return method_supports_version(ssl->method, version) &&
ssl_protocol_version_from_wire(&protocol_version, version) &&
hs->min_version <= protocol_version &&
protocol_version <= hs->max_version;
}
int ssl_add_supported_versions(SSL_HANDSHAKE *hs, CBB *cbb) {
const uint16_t *versions;
size_t num_versions;
get_method_versions(hs->ssl->method, &versions, &num_versions);
for (size_t i = 0; i < num_versions; i++) {
if (ssl_supports_version(hs, versions[i]) &&
!CBB_add_u16(cbb, versions[i])) {
return 0;
}
}
return 1;
}
int ssl_negotiate_version(SSL_HANDSHAKE *hs, uint8_t *out_alert,
uint16_t *out_version, const CBS *peer_versions) {
const uint16_t *versions;
size_t num_versions;
get_method_versions(hs->ssl->method, &versions, &num_versions);
for (size_t i = 0; i < num_versions; i++) {
if (!ssl_supports_version(hs, versions[i])) {
continue;
}
CBS copy = *peer_versions;
while (CBS_len(&copy) != 0) {
uint16_t version;
if (!CBS_get_u16(&copy, &version)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (version == versions[i]) {
*out_version = version;
return 1;
}
}
}
OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_PROTOCOL);
*out_alert = SSL_AD_PROTOCOL_VERSION;
return 0;
}
} // namespace bssl
using namespace bssl;
int SSL_CTX_set_min_proto_version(SSL_CTX *ctx, uint16_t version) {
return set_min_version(ctx->method, &ctx->conf_min_version, version);
}
int SSL_CTX_set_max_proto_version(SSL_CTX *ctx, uint16_t version) {
return set_max_version(ctx->method, &ctx->conf_max_version, version);
}
int SSL_set_min_proto_version(SSL *ssl, uint16_t version) {
return set_min_version(ssl->method, &ssl->conf_min_version, version);
}
int SSL_set_max_proto_version(SSL *ssl, uint16_t version) {
return set_max_version(ssl->method, &ssl->conf_max_version, version);
}
int SSL_version(const SSL *ssl) {
uint16_t ret = ssl_version(ssl);
/* Report TLS 1.3 draft version as TLS 1.3 in the public API. */
if (ret == TLS1_3_DRAFT_VERSION || ret == TLS1_3_EXPERIMENT_VERSION ||
ret == TLS1_3_RECORD_TYPE_EXPERIMENT_VERSION) {
return TLS1_3_VERSION;
}
return ret;
}
const char *SSL_get_version(const SSL *ssl) {
return ssl_version_to_string(ssl_version(ssl));
}
const char *SSL_SESSION_get_version(const SSL_SESSION *session) {
return ssl_version_to_string(session->ssl_version);
}