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-rw-r--r--src/ssl/ssl_versions.cc373
1 files changed, 373 insertions, 0 deletions
diff --git a/src/ssl/ssl_versions.cc b/src/ssl/ssl_versions.cc
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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"
+
+
+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);
+}
+
+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);
+}
+
+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;
+}
+
+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;
+}
+
+static const char *ssl_get_version(int 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";
+ }
+}
+
+const char *SSL_get_version(const SSL *ssl) {
+ return ssl_get_version(ssl_version(ssl));
+}
+
+const char *SSL_SESSION_get_version(const SSL_SESSION *session) {
+ return ssl_get_version(session->ssl_version);
+}
+
+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 &&
+ 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;
+}
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