Protocol version selection and negotiation rewrite

The protocol selection code is now consolidated in a few consecutive
short functions in a single file and is table driven.  Protocol-specific
constraints that influence negotiation are moved into the flags
field of the method structure.  The same protocol version constraints
are now applied in all code paths.  It is now much easier to add
new protocol versions without reworking the protocol selection
logic.

In the presence of "holes" in the list of enabled client protocols
we no longer select client protocols below the hole based on a
subset of the constraints and then fail shortly after when it is
found that these don't meet the remaining constraints (suiteb, FIPS,
security level, ...).  Ideally, with the new min/max controls users
will be less likely to create "holes" in the first place.

Reviewed-by: Kurt Roeckx <kurt@openssl.org>

14 files changed, 537 insertions, 473 deletions

diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
index a510b5bebe..3cd4b786e4 100644
--- a/ssl/d1_lib.c
+++ b/ssl/d1_lib.c
@@ -235,7 +235,7 @@ void dtls1_clear(SSL *s)
     if (s->options & SSL_OP_CISCO_ANYCONNECT)
         s->client_version = s->version = DTLS1_BAD_VER;
     else if (s->method->version == DTLS_ANY_VERSION)
-        s->version = DTLS1_2_VERSION;
+        s->version = DTLS_MAX_VERSION;
     else
         s->version = s->method->version;
 }
@@ -256,38 +256,6 @@ long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
     case DTLS_CTRL_LISTEN:
         ret = dtls1_listen(s, parg);
         break;
-    case SSL_CTRL_CHECK_PROTO_VERSION:
-        /*
-         * For library-internal use; checks that the current protocol is the
-         * is the highest enabled version.
-         */
-        if (s->max_proto_version == 0 && s->version == DTLS_MAX_VERSION)
-            return 1;
-        if (s->max_proto_version != 0 && s->version == s->max_proto_version)
-            return 1;
-        /* We're not limited by the max_proto_version but might still have
-         * other reasons why we use an older version like not using a
-         * version-flexible SSL_METHOD.  Check s->ctx->method as version
-         * negotiation may have changed s->method.
-         * This check can be removed when we only have version-flexible
-         * SSL_METHODs
-         */
-        if (s->version == s->ctx->method->version)
-            return 1;
-        /*
-         * Apparently we're using a version-flexible SSL_METHOD (not at its
-         * highest protocol version, not limited by max_proto_version).
-         */
-        if (s->ctx->method->version == DTLS_method()->version) {
-#if DTLS_MAX_VERSION != DTLS1_2_VERSION
-# error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
-#endif
-            if (!(s->options & SSL_OP_NO_DTLSv1_2))
-                return s->version == DTLS1_2_VERSION;
-            if (!(s->options & SSL_OP_NO_DTLSv1))
-                return s->version == DTLS1_VERSION;
-        }
-        return 0;               /* Unexpected state; fail closed. */
     case DTLS_CTRL_SET_LINK_MTU:
         if (larg < (long)dtls1_link_min_mtu())
             return 0;
@@ -708,8 +676,8 @@ int dtls1_listen(SSL *s, struct sockaddr *client)
         /*
          * Verify client version is supported
          */
-        if ((clientvers > (unsigned int)s->method->version &&
-                              s->method->version != DTLS_ANY_VERSION)) {
+        if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
+            s->method->version != DTLS_ANY_VERSION) {
             SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
             goto end;
         }
diff --git a/ssl/methods.c b/ssl/methods.c
index ef20c9ca3e..7a8bb11b77 100644
--- a/ssl/methods.c
+++ b/ssl/methods.c
@@ -135,19 +135,23 @@ static const SSL_METHOD *tls1_get_method(int ver)
     return NULL;
 }
 
-IMPLEMENT_tls_meth_func(TLS_ANY_VERSION, TLS_method,
+IMPLEMENT_tls_meth_func(TLS_ANY_VERSION, 0, 0,
+                        TLS_method,
                         ossl_statem_accept,
                         ossl_statem_connect, tls1_get_method, TLSv1_2_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_2_VERSION, TLSv1_2_method,
+IMPLEMENT_tls_meth_func(TLS1_2_VERSION, 0, SSL_OP_NO_TLSv1_2,
+                        TLSv1_2_method,
                         ossl_statem_accept,
                         ossl_statem_connect, tls1_get_method, TLSv1_2_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_1_VERSION, TLSv1_1_method,
+IMPLEMENT_tls_meth_func(TLS1_1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_TLSv1_1,
+                        TLSv1_1_method,
                         ossl_statem_accept,
                         ossl_statem_connect, tls1_get_method, TLSv1_1_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_VERSION, TLSv1_method,
+IMPLEMENT_tls_meth_func(TLS1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_TLSv1,
+                        TLSv1_method,
                         ossl_statem_accept,
                         ossl_statem_connect, tls1_get_method, TLSv1_enc_data)
 
@@ -178,22 +182,26 @@ static const SSL_METHOD *tls1_get_server_method(int ver)
     return NULL;
 }
 
-IMPLEMENT_tls_meth_func(TLS_ANY_VERSION, TLS_server_method,
+IMPLEMENT_tls_meth_func(TLS_ANY_VERSION, 0, 0,
+                        TLS_server_method,
                         ossl_statem_accept,
                         ssl_undefined_function,
                         tls1_get_server_method, TLSv1_2_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_2_VERSION, TLSv1_2_server_method,
+IMPLEMENT_tls_meth_func(TLS1_2_VERSION, 0, SSL_OP_NO_TLSv1_2,
+                        TLSv1_2_server_method,
                         ossl_statem_accept,
                         ssl_undefined_function,
                         tls1_get_server_method, TLSv1_2_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_1_VERSION, TLSv1_1_server_method,
+IMPLEMENT_tls_meth_func(TLS1_1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_TLSv1_1,
+                        TLSv1_1_server_method,
                         ossl_statem_accept,
                         ssl_undefined_function,
                         tls1_get_server_method, TLSv1_1_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_VERSION, TLSv1_server_method,
+IMPLEMENT_tls_meth_func(TLS1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_TLSv1,
+                        TLSv1_server_method,
                         ossl_statem_accept,
                         ssl_undefined_function,
                         tls1_get_server_method, TLSv1_enc_data)
@@ -226,22 +234,26 @@ static const SSL_METHOD *tls1_get_client_method(int ver)
     return NULL;
 }
 
-IMPLEMENT_tls_meth_func(TLS_ANY_VERSION, TLS_client_method,
+IMPLEMENT_tls_meth_func(TLS_ANY_VERSION, 0, 0,
+                        TLS_client_method,
                         ssl_undefined_function,
                         ossl_statem_connect,
                         tls1_get_client_method, TLSv1_2_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_2_VERSION, TLSv1_2_client_method,
+IMPLEMENT_tls_meth_func(TLS1_2_VERSION, 0, SSL_OP_NO_TLSv1_2,
+                        TLSv1_2_client_method,
                         ssl_undefined_function,
                         ossl_statem_connect,
                         tls1_get_client_method, TLSv1_2_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_1_VERSION, TLSv1_1_client_method,
+IMPLEMENT_tls_meth_func(TLS1_1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_TLSv1_1,
+                        TLSv1_1_client_method,
                         ssl_undefined_function,
                         ossl_statem_connect,
                         tls1_get_client_method, TLSv1_1_enc_data)
 
-IMPLEMENT_tls_meth_func(TLS1_VERSION, TLSv1_client_method,
+IMPLEMENT_tls_meth_func(TLS1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_TLSv1,
+                        TLSv1_client_method,
                         ssl_undefined_function,
                         ossl_statem_connect,
                         tls1_get_client_method, TLSv1_enc_data)
@@ -268,19 +280,19 @@ static const SSL_METHOD *dtls1_get_method(int ver)
         return NULL;
 }
 
-IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_DTLSv1,
                           DTLSv1_method,
                           ossl_statem_accept,
                           ossl_statem_connect,
                           dtls1_get_method, DTLSv1_enc_data)
 
-IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION, 0, SSL_OP_NO_DTLSv1_2,
                           DTLSv1_2_method,
                           ossl_statem_accept,
                           ossl_statem_connect,
                           dtls1_get_method, DTLSv1_2_enc_data)
 
-IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION, 0, 0,
                           DTLS_method,
                           ossl_statem_accept,
                           ossl_statem_connect,
@@ -303,19 +315,19 @@ static const SSL_METHOD *dtls1_get_server_method(int ver)
         return NULL;
 }
 
-IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_DTLSv1,
                           DTLSv1_server_method,
                           ossl_statem_accept,
                           ssl_undefined_function,
                           dtls1_get_server_method, DTLSv1_enc_data)
 
-IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION, 0, SSL_OP_NO_DTLSv1_2,
                           DTLSv1_2_server_method,
                           ossl_statem_accept,
                           ssl_undefined_function,
                           dtls1_get_server_method, DTLSv1_2_enc_data)
 
-IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION, 0, 0,
                           DTLS_server_method,
                           ossl_statem_accept,
                           ssl_undefined_function,
@@ -338,19 +350,19 @@ static const SSL_METHOD *dtls1_get_client_method(int ver)
         return NULL;
 }
 
-IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS1_VERSION, SSL_METHOD_NO_SUITEB, SSL_OP_NO_DTLSv1,
                           DTLSv1_client_method,
                           ssl_undefined_function,
                           ossl_statem_connect,
                           dtls1_get_client_method, DTLSv1_enc_data)
 
-IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION, 0, SSL_OP_NO_DTLSv1_2,
                           DTLSv1_2_client_method,
                           ssl_undefined_function,
                           ossl_statem_connect,
                           dtls1_get_client_method, DTLSv1_2_enc_data)
 
-IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
+IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION, 0, 0,
                           DTLS_client_method,
                           ssl_undefined_function,
                           ossl_statem_connect,
diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index e3e4fd34f8..d307ec05d6 100644
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -3777,33 +3777,6 @@ long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg)
         }
 #endif
 
-    case SSL_CTRL_CHECK_PROTO_VERSION:
-        /*
-         * For library-internal use; checks 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) {
-#if TLS_MAX_VERSION != TLS1_2_VERSION
-# error Code needs update for TLS_method() support beyond TLS1_2_VERSION.
-#endif
-            if (!(s->options & SSL_OP_NO_TLSv1_2))
-                return s->version == TLS1_2_VERSION;
-            if (!(s->options & SSL_OP_NO_TLSv1_1))
-                return s->version == TLS1_1_VERSION;
-            if (!(s->options & SSL_OP_NO_TLSv1))
-                return s->version == TLS1_VERSION;
-            if (!(s->options & SSL_OP_NO_SSLv3))
-                return s->version == SSL3_VERSION;
-        }
-        return 0;               /* Unexpected state; fail closed. */
-
     default:
         break;
     }
diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index f01d3a7835..597de0ad6c 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -1084,15 +1084,21 @@ static int ssl_security_default_callback(SSL *s, SSL_CTX *ctx, int op,
             break;
         }
     case SSL_SECOP_VERSION:
-        /* SSLv3 not allowed on level 2 */
-        if (nid <= SSL3_VERSION && level >= 2)
-            return 0;
-        /* TLS v1.1 and above only for level 3 */
-        if (nid <= TLS1_VERSION && level >= 3)
-            return 0;
-        /* TLS v1.2 only for level 4 and above */
-        if (nid <= TLS1_1_VERSION && level >= 4)
-            return 0;
+        if (!SSL_IS_DTLS(s)) {
+            /* SSLv3 not allowed at level 2 */
+            if (nid <= SSL3_VERSION && level >= 2)
+                return 0;
+            /* TLS v1.1 and above only for level 3 */
+            if (nid <= TLS1_VERSION && level >= 3)
+                return 0;
+            /* TLS v1.2 only for level 4 and above */
+            if (nid <= TLS1_1_VERSION && level >= 4)
+                return 0;
+        } else {
+            /* DTLS v1.2 only for level 4 and above */
+            if (DTLS_VERSION_LT(nid, DTLS1_2_VERSION) && level >= 4)
+                return 0;
+        }
         break;
 
     case SSL_SECOP_COMPRESSION:
diff --git a/ssl/ssl_ciph.c b/ssl/ssl_ciph.c
index 65a5bb6c96..a15248d41b 100644
--- a/ssl/ssl_ciph.c
+++ b/ssl/ssl_ciph.c
@@ -1349,12 +1349,8 @@ static int check_suiteb_cipher_list(const SSL_METHOD *meth, CERT *c,
     /* Check version: if TLS 1.2 ciphers allowed we can use Suite B */
 
     if (!(meth->ssl3_enc->enc_flags & SSL_ENC_FLAG_TLS1_2_CIPHERS)) {
-        if (meth->ssl3_enc->enc_flags & SSL_ENC_FLAG_DTLS)
-            SSLerr(SSL_F_CHECK_SUITEB_CIPHER_LIST,
-                   SSL_R_ONLY_DTLS_1_2_ALLOWED_IN_SUITEB_MODE);
-        else
-            SSLerr(SSL_F_CHECK_SUITEB_CIPHER_LIST,
-                   SSL_R_ONLY_TLS_1_2_ALLOWED_IN_SUITEB_MODE);
+        SSLerr(SSL_F_CHECK_SUITEB_CIPHER_LIST,
+               SSL_R_AT_LEAST_TLS_1_2_NEEDED_IN_SUITEB_MODE);
         return 0;
     }
 # ifndef OPENSSL_NO_EC
diff --git a/ssl/ssl_conf.c b/ssl/ssl_conf.c
index 1e14a4497e..9529d30842 100644
--- a/ssl/ssl_conf.c
+++ b/ssl/ssl_conf.c
@@ -347,6 +347,22 @@ static int protocol_from_string(const char *value)
     return -1;
 }
 
+static int min_max_proto(SSL_CONF_CTX *cctx, const char *value, int *bound)
+{
+    int method_version;
+    int new_version;
+
+    if (cctx->ctx != NULL)
+        method_version = cctx->ctx->method->version;
+    else if (cctx->ssl != NULL)
+        method_version = cctx->ssl->ctx->method->version;
+    else
+        return 0;
+    if ((new_version = protocol_from_string(value)) < 0)
+        return 0;
+    return ssl_set_version_bound(method_version, new_version, bound);
+}
+
 /*
  * cmd_MinProtocol - Set min protocol version
  * @cctx: config structure to save settings in
@@ -356,13 +372,7 @@ static int protocol_from_string(const char *value)
  */
 static int cmd_MinProtocol(SSL_CONF_CTX *cctx, const char *value)
 {
-    int version = protocol_from_string(value);
-
-    if (version < 0)
-        return 0;
-
-    *(cctx->min_version) = version;
-    return 1;
+    return min_max_proto(cctx, value, cctx->min_version);
 }
 
 /*
@@ -374,13 +384,7 @@ static int cmd_MinProtocol(SSL_CONF_CTX *cctx, const char *value)
  */
 static int cmd_MaxProtocol(SSL_CONF_CTX *cctx, const char *value)
 {
-    int version = protocol_from_string(value);
-
-    if (version < 0)
-        return 0;
-
-    *(cctx->max_version) = version;
-    return 1;
+    return min_max_proto(cctx, value, cctx->max_version);
 }
 
 static int cmd_Options(SSL_CONF_CTX *cctx, const char *value)
diff --git a/ssl/ssl_err.c b/ssl/ssl_err.c
index 0c40b7b3ec..d9dbf99391 100644
--- a/ssl/ssl_err.c
+++ b/ssl/ssl_err.c
@@ -314,7 +314,6 @@ static ERR_STRING_DATA SSL_str_functs[] = {
     {ERR_FUNC(SSL_F_SSL_SET_SESSION_TICKET_EXT),
      "SSL_set_session_ticket_ext"},
     {ERR_FUNC(SSL_F_SSL_SET_TRUST), "SSL_set_trust"},
-    {ERR_FUNC(SSL_F_SSL_SET_VERSION), "SSL_SET_VERSION"},
     {ERR_FUNC(SSL_F_SSL_SET_WFD), "SSL_set_wfd"},
     {ERR_FUNC(SSL_F_SSL_SHUTDOWN), "SSL_shutdown"},
     {ERR_FUNC(SSL_F_SSL_SRP_CTX_INIT), "SSL_SRP_CTX_init"},
@@ -416,6 +415,10 @@ static ERR_STRING_DATA SSL_str_reasons[] = {
     {ERR_REASON(SSL_R_APP_DATA_IN_HANDSHAKE), "app data in handshake"},
     {ERR_REASON(SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT),
      "attempt to reuse session in different context"},
+    {ERR_REASON(SSL_R_AT_LEAST_TLS_1_0_NEEDED_IN_FIPS_MODE),
+     "at least TLS 1.0 needed in FIPS mode"},
+    {ERR_REASON(SSL_R_AT_LEAST_TLS_1_2_NEEDED_IN_SUITEB_MODE),
+     "at least (D)TLS 1.2 needed in Suite B mode"},
     {ERR_REASON(SSL_R_BAD_ALERT_RECORD), "bad alert record"},
     {ERR_REASON(SSL_R_BAD_CHANGE_CIPHER_SPEC), "bad change cipher spec"},
     {ERR_REASON(SSL_R_BAD_DATA), "bad data"},
@@ -603,14 +606,6 @@ static ERR_STRING_DATA SSL_str_reasons[] = {
      "old session cipher not returned"},
     {ERR_REASON(SSL_R_OLD_SESSION_COMPRESSION_ALGORITHM_NOT_RETURNED),
      "old session compression algorithm not returned"},
-    {ERR_REASON(SSL_R_ONLY_DTLS_1_2_ALLOWED_IN_SUITEB_MODE),
-     "only DTLS 1.2 allowed in Suite B mode"},
-    {ERR_REASON(SSL_R_ONLY_TLS_1_2_ALLOWED_IN_SUITEB_MODE),
-     "only TLS 1.2 allowed in Suite B mode"},
-    {ERR_REASON(SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE),
-     "only tls allowed in fips mode"},
-    {ERR_REASON(SSL_R_OPAQUE_PRF_INPUT_TOO_LONG),
-     "opaque PRF input too long"},
     {ERR_REASON(SSL_R_PACKET_LENGTH_TOO_LONG), "packet length too long"},
     {ERR_REASON(SSL_R_PARSE_TLSEXT), "parse tlsext"},
     {ERR_REASON(SSL_R_PATH_TOO_LONG), "path too long"},
@@ -794,6 +789,7 @@ static ERR_STRING_DATA SSL_str_reasons[] = {
     {ERR_REASON(SSL_R_UNSUPPORTED_SSL_VERSION), "unsupported ssl version"},
     {ERR_REASON(SSL_R_UNSUPPORTED_STATUS_TYPE), "unsupported status type"},
     {ERR_REASON(SSL_R_USE_SRTP_NOT_NEGOTIATED), "use srtp not negotiated"},
+    {ERR_REASON(SSL_R_VERSION_TOO_HIGH), "version too high"},
     {ERR_REASON(SSL_R_VERSION_TOO_LOW), "version too low"},
     {ERR_REASON(SSL_R_WRONG_CERTIFICATE_TYPE), "wrong certificate type"},
     {ERR_REASON(SSL_R_WRONG_CIPHER_RETURNED), "wrong cipher returned"},
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index cfc73de9ca..760014d739 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -1201,11 +1201,11 @@ long SSL_ctrl(SSL *s, int cmd, long larg, void *parg)
         else
             return 0;
     case SSL_CTRL_SET_MIN_PROTO_VERSION:
-        s->min_proto_version = larg;
-        return 1;
+        return ssl_set_version_bound(s->ctx->method->version, (int)larg,
+                                     &s->min_proto_version);
     case SSL_CTRL_SET_MAX_PROTO_VERSION:
-        s->max_proto_version = larg;
-        return 1;
+        return ssl_set_version_bound(s->ctx->method->version, (int)larg,
+                                     &s->max_proto_version);
     default:
         return (s->method->ssl_ctrl(s, cmd, larg, parg));
     }
@@ -1323,11 +1323,11 @@ long SSL_CTX_ctrl(SSL_CTX *ctx, int cmd, long larg, void *parg)
     case SSL_CTRL_CLEAR_CERT_FLAGS:
         return (ctx->cert->cert_flags &= ~larg);
     case SSL_CTRL_SET_MIN_PROTO_VERSION:
-        ctx->min_proto_version = larg;
-        return 1;
+        return ssl_set_version_bound(ctx->method->version, (int)larg,
+                                     &ctx->min_proto_version);
     case SSL_CTRL_SET_MAX_PROTO_VERSION:
-        ctx->max_proto_version = larg;
-        return 1;
+        return ssl_set_version_bound(ctx->method->version, (int)larg,
+                                     &ctx->max_proto_version);
     default:
         return (ctx->method->ssl_ctx_ctrl(ctx, cmd, larg, parg));
     }
@@ -1795,7 +1795,7 @@ SSL_CTX *SSL_CTX_new(const SSL_METHOD *meth)
     }
 
     if (FIPS_mode() && (meth->version < TLS1_VERSION)) {
-        SSLerr(SSL_F_SSL_CTX_NEW, SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE);
+        SSLerr(SSL_F_SSL_CTX_NEW, SSL_R_AT_LEAST_TLS_1_0_NEEDED_IN_FIPS_MODE);
         return NULL;
     }
 
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 9482fc91ad..7e07297f2f 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -471,8 +471,8 @@
  * flags because it may not be set to correct version yet.
  */
 # define SSL_CLIENT_USE_TLS1_2_CIPHERS(s)        \
-                ((SSL_IS_DTLS(s) && s->client_version <= DTLS1_2_VERSION) || \
-                (!SSL_IS_DTLS(s) && s->client_version >= TLS1_2_VERSION))
+    ((!SSL_IS_DTLS(s) && s->client_version >= TLS1_2_VERSION) || \
+     (SSL_IS_DTLS(s) && DTLS_VERSION_GE(s->client_version, DTLS1_2_VERSION)))
 
 # ifdef TLSEXT_TYPE_encrypt_then_mac
 #  define SSL_USE_ETM(s) (s->s3->flags & TLS1_FLAGS_ENCRYPT_THEN_MAC)
@@ -535,6 +535,8 @@ struct ssl_cipher_st {
 /* Used to hold SSL/TLS functions */
 struct ssl_method_st {
     int version;
+    unsigned flags;
+    unsigned long mask;
     int (*ssl_new) (SSL *s);
     void (*ssl_clear) (SSL *s);
     void (*ssl_free) (SSL *s);
@@ -1685,12 +1687,20 @@ extern const SSL3_ENC_METHOD SSLv3_enc_data;
 extern const SSL3_ENC_METHOD DTLSv1_enc_data;
 extern const SSL3_ENC_METHOD DTLSv1_2_enc_data;
 
-# define IMPLEMENT_tls_meth_func(version, func_name, s_accept, s_connect, \
-                                s_get_meth, enc_data) \
+/*
+ * Flags for SSL methods
+ */
+#define SSL_METHOD_NO_FIPS      (1U<<0)
+#define SSL_METHOD_NO_SUITEB    (1U<<1)
+
+# define IMPLEMENT_tls_meth_func(version, flags, mask, func_name, s_accept, \
+                                 s_connect, s_get_meth, enc_data) \
 const SSL_METHOD *func_name(void)  \
         { \
         static const SSL_METHOD func_name##_data= { \
                 version, \
+                flags, \
+                mask, \
                 tls1_new, \
                 tls1_clear, \
                 tls1_free, \
@@ -1727,6 +1737,8 @@ const SSL_METHOD *func_name(void)  \
         { \
         static const SSL_METHOD func_name##_data= { \
                 SSL3_VERSION, \
+                SSL_METHOD_NO_FIPS | SSL_METHOD_NO_SUITEB, \
+                SSL_OP_NO_SSLv3, \
                 ssl3_new, \
                 ssl3_clear, \
                 ssl3_free, \
@@ -1758,12 +1770,14 @@ const SSL_METHOD *func_name(void)  \
         return &func_name##_data; \
         }
 
-# define IMPLEMENT_dtls1_meth_func(version, func_name, s_accept, s_connect, \
-                                        s_get_meth, enc_data) \
+# define IMPLEMENT_dtls1_meth_func(version, flags, mask, func_name, s_accept, \
+                                        s_connect, s_get_meth, enc_data) \
 const SSL_METHOD *func_name(void)  \
         { \
         static const SSL_METHOD func_name##_data= { \
                 version, \
+                flags, \
+                mask, \
                 dtls1_new, \
                 dtls1_clear, \
                 dtls1_free, \
@@ -1911,6 +1925,12 @@ __owur int ssl3_handshake_write(SSL *s);
 
 __owur int ssl_allow_compression(SSL *s);
 
+__owur int ssl_set_client_hello_version(SSL *s);
+__owur int ssl_check_version_downgrade(SSL *s);
+__owur int ssl_set_version_bound(int method_version, int version, int *bound);
+__owur int ssl_choose_server_version(SSL *s);
+__owur int ssl_choose_client_version(SSL *s, int version);
+
 __owur long tls1_default_timeout(void);
 __owur int dtls1_do_write(SSL *s, int type);
 void dtls1_set_message_header(SSL *s,
diff --git a/ssl/statem/statem.c b/ssl/statem/statem.c
index bc3fc54fab..a03fe32083 100644
--- a/ssl/statem/statem.c
+++ b/ssl/statem/statem.c
@@ -261,7 +261,8 @@ static void (*get_callback(SSL *s))(const SSL *, int, int)
  *   1: Success
  * <=0: NBIO or error
  */
-static int state_machine(SSL *s, int server) {
+static int state_machine(SSL *s, int server)
+{
     BUF_MEM *buf = NULL;
     unsigned long Time = (unsigned long)time(NULL);
     void (*cb) (const SSL *ssl, int type, int val) = NULL;
@@ -336,19 +337,15 @@ static int state_machine(SSL *s, int server) {
                 goto end;
             }
         } else {
-            if ((s->version >> 8) != SSL3_VERSION_MAJOR
-                    && s->version != TLS_ANY_VERSION) {
+            if ((s->version >> 8) != SSL3_VERSION_MAJOR) {
                 SSLerr(SSL_F_STATE_MACHINE, ERR_R_INTERNAL_ERROR);
                 goto end;
             }
         }
 
-        if (!SSL_IS_DTLS(s)) {
-            if (s->version != TLS_ANY_VERSION &&
-                    !ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
-                SSLerr(SSL_F_STATE_MACHINE, SSL_R_VERSION_TOO_LOW);
-                goto end;
-            }
+        if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
+            SSLerr(SSL_F_STATE_MACHINE, SSL_R_VERSION_TOO_LOW);
+            goto end;
         }
 
         if (s->init_buf == NULL) {
diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index 26acdc5488..cfbfa5f8c3 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -166,7 +166,6 @@
 
 static ossl_inline int cert_req_allowed(SSL *s);
 static int key_exchange_expected(SSL *s);
-static int ssl_set_version(SSL *s);
 static int ca_dn_cmp(const X509_NAME *const *a, const X509_NAME *const *b);
 static int ssl_cipher_list_to_bytes(SSL *s, STACK_OF(SSL_CIPHER) *sk,
                                     unsigned char *p);
@@ -800,128 +799,12 @@ WORK_STATE ossl_statem_client_post_process_message(SSL *s, WORK_STATE wst)
     return WORK_ERROR;
 }
 
-/*
- * Work out what version we should be using for the initial ClientHello if
- * the version is currently set to (D)TLS_ANY_VERSION.
- * Returns 1 on success
- * Returns 0 on error
- */
-static int ssl_set_version(SSL *s)
-{
-    unsigned long mask, options = s->options;
-
-    if (s->method->version == TLS_ANY_VERSION) {
-        /*
-         * SSL_OP_NO_X disables all protocols above X *if* there are
-         * some protocols below X enabled. This is required in order
-         * to maintain "version capability" vector contiguous. So
-         * that if application wants to disable TLS1.0 in favour of
-         * TLS1>=1, it would be insufficient to pass SSL_NO_TLSv1, the
-         * answer is SSL_OP_NO_TLSv1|SSL_OP_NO_SSLv3.
-         */
-        mask = SSL_OP_NO_TLSv1_1 | SSL_OP_NO_TLSv1
-#if !defined(OPENSSL_NO_SSL3)
-            | SSL_OP_NO_SSLv3
-#endif
-            ;
-#if !defined(OPENSSL_NO_TLS1_2_CLIENT)
-        if (options & SSL_OP_NO_TLSv1_2) {
-            if ((options & mask) != mask) {
-                s->version = TLS1_1_VERSION;
-            } else {
-                SSLerr(SSL_F_SSL_SET_VERSION, SSL_R_NO_PROTOCOLS_AVAILABLE);
-                return 0;
-            }
-        } else {
-            s->version = TLS1_2_VERSION;
-        }
-#else
-        if ((options & mask) == mask) {
-            SSLerr(SSL_F_SSL_SET_VERSION, SSL_R_NO_PROTOCOLS_AVAILABLE);
-            return 0;
-        }
-        s->version = TLS1_1_VERSION;
-#endif
-
-        mask &= ~SSL_OP_NO_TLSv1_1;
-        if ((options & SSL_OP_NO_TLSv1_1) && (options & mask) != mask)
-            s->version = TLS1_VERSION;
-        mask &= ~SSL_OP_NO_TLSv1;
-#if !defined(OPENSSL_NO_SSL3)
-        if ((options & SSL_OP_NO_TLSv1) && (options & mask) != mask)
-            s->version = SSL3_VERSION;
-#endif
-
-        if (s->max_proto_version != 0 && (s->version > s->max_proto_version))
-            s->version = s->max_proto_version;
-        if (s->version < s->min_proto_version)
-        {
-            SSLerr(SSL_F_SSL_SET_VERSION, SSL_R_NO_PROTOCOLS_AVAILABLE);
-            return 0;
-        }
-
-        if (s->version != TLS1_2_VERSION && tls1_suiteb(s)) {
-            SSLerr(SSL_F_SSL_SET_VERSION,
-                   SSL_R_ONLY_TLS_1_2_ALLOWED_IN_SUITEB_MODE);
-            return 0;
-        }
-
-        if (s->version == SSL3_VERSION && FIPS_mode()) {
-            SSLerr(SSL_F_SSL_SET_VERSION, SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE);
-            return 0;
-        }
-
-    } else if (s->method->version == DTLS_ANY_VERSION) {
-        int max_version = DTLS_MAX_VERSION;
-        int min_version = DTLS_MIN_VERSION;
-
-        if (s->max_proto_version != 0)
-            max_version = s->max_proto_version;
-        if (s->min_proto_version != 0)
-            min_version = s->min_proto_version;
-
-        /* If DTLS 1.2 disabled correct the version number */
-        if (options & SSL_OP_NO_DTLSv1_2
-            || DTLS_VERSION_GT(DTLS1_2_VERSION, max_version)) {
-            if (tls1_suiteb(s)) {
-                SSLerr(SSL_F_SSL_SET_VERSION,
-                       SSL_R_ONLY_DTLS_1_2_ALLOWED_IN_SUITEB_MODE);
-                return 0;
-            }
-            /*
-             * Disabling all versions is silly: return an error.
-             */
-            if (options & SSL_OP_NO_DTLSv1
-                || DTLS_VERSION_GT(min_version, DTLS1_VERSION)) {
-                SSLerr(SSL_F_SSL_SET_VERSION, SSL_R_WRONG_SSL_VERSION);
-                return 0;
-            }
-            /*
-             * Update method so we don't use any DTLS 1.2 features.
-             */
-            s->method = DTLSv1_client_method();
-            s->version = DTLS1_VERSION;
-        } else {
-            /*
-             * We only support one version: update method
-             */
-            if (options & SSL_OP_NO_DTLSv1
-                || DTLS_VERSION_GE(min_version, DTLS1_2_VERSION))
-                s->method = DTLSv1_2_client_method();
-            s->version = DTLS1_2_VERSION;
-        }
-    }
-
-    s->client_version = s->version;
-
-    return 1;
-}
-
 int tls_construct_client_hello(SSL *s)
 {
     unsigned char *buf;
     unsigned char *p, *d;
     int i;
+    int protverr;
     unsigned long l;
     int al = 0;
 #ifndef OPENSSL_NO_COMP
@@ -933,8 +816,11 @@ int tls_construct_client_hello(SSL *s)
     buf = (unsigned char *)s->init_buf->data;
 
     /* Work out what SSL/TLS/DTLS version to use */
-    if (ssl_set_version(s) == 0)
+    protverr = ssl_set_client_hello_version(s);
+    if (protverr != 0) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, protverr);
         goto err;
+    }
 
     if ((sess == NULL) || (sess->ssl_version != s->version) ||
         /*
@@ -1141,121 +1027,23 @@ MSG_PROCESS_RETURN tls_process_server_hello(SSL *s, PACKET *pkt)
     unsigned char *cipherchars;
     int i, al = SSL_AD_INTERNAL_ERROR;
     unsigned int compression;
+    unsigned int sversion;
+    int protverr;
 #ifndef OPENSSL_NO_COMP
     SSL_COMP *comp;
 #endif
 
-    if (s->method->version == TLS_ANY_VERSION) {
-        unsigned int sversion;
-        int max_version = TLS_MAX_VERSION;
-
-        if (s->max_proto_version != 0)
-            max_version = s->max_proto_version;
-
-        if (!PACKET_get_net_2(pkt, &sversion)) {
-            al = SSL_AD_DECODE_ERROR;
-            SSLerr(SSL_F_TLS_PROCESS_SERVER_HELLO, SSL_R_LENGTH_MISMATCH);
-            goto f_err;
-        }
-
-#if TLS_MAX_VERSION != TLS1_2_VERSION
-#error Code needs updating for new TLS version
-#endif
-#ifndef OPENSSL_NO_SSL3
-        if ((sversion == SSL3_VERSION) && !(s->options & SSL_OP_NO_SSLv3) &&
-            (s->min_proto_version <= SSL3_VERSION) &&
-            (max_version >= SSL3_VERSION)) {
-            if (FIPS_mode()) {
-                SSLerr(SSL_F_TLS_PROCESS_SERVER_HELLO,
-                       SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE);
-                al = SSL_AD_PROTOCOL_VERSION;
-                goto f_err;
-            }
-            s->method = SSLv3_client_method();
-        } else
-#endif</