@@ -661,4 +661,71 @@ EC_GROUP_order_bits(const EC_GROUP *group)

 #define RSA_F_RSA_OSSL_PRIVATE_ENCRYPT       RSA_F_RSA_EAY_PRIVATE_ENCRYPT

 #endif

+#ifndef SSL_CTX_get_min_proto_version

+/** Dummy SSL_CTX_get_min_proto_version for OpenSSL < 1.1 (not really needed) */

+static inline int

+SSL_CTX_get_min_proto_version(SSL_CTX *ctx)

+{

+    return 0;

+}

+#endif /* SSL_CTX_get_min_proto_version */

+

+#ifndef SSL_CTX_set_min_proto_version

+/** Mimics SSL_CTX_set_min_proto_version for OpenSSL < 1.1 */

+static inline int

+SSL_CTX_set_min_proto_version(SSL_CTX *ctx, long tls_ver_min)

+{

+    long sslopt = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3; /* Never do < TLS 1.0 */

+

+    if (tls_ver_min > TLS1_VERSION)

+    {

+        sslopt |= SSL_OP_NO_TLSv1;

+    }

+#ifdef SSL_OP_NO_TLSv1_1

+    if (tls_ver_min > TLS1_1_VERSION)

+    {

+        sslopt |= SSL_OP_NO_TLSv1_1;

+    }

+#endif

+#ifdef SSL_OP_NO_TLSv1_2

+    if (tls_ver_min > TLS1_2_VERSION)

+    {

+        sslopt |= SSL_OP_NO_TLSv1_2;

+    }

+#endif

+    SSL_CTX_set_options(ctx, sslopt);

+

+    return 1;

+}

+#endif /* SSL_CTX_set_min_proto_version */

+

+#ifndef SSL_CTX_set_max_proto_version

+/** Mimics SSL_CTX_set_max_proto_version for OpenSSL < 1.1 */

+static inline int

+SSL_CTX_set_max_proto_version(SSL_CTX *ctx, long tls_ver_max)

+{

+    long sslopt = 0;

+

+    if (tls_ver_max < TLS1_VERSION)

+    {

+        sslopt |= SSL_OP_NO_TLSv1;

+    }

+#ifdef SSL_OP_NO_TLSv1_1

+    if (tls_ver_max < TLS1_1_VERSION)

+    {

+        sslopt |= SSL_OP_NO_TLSv1_1;

+    }

+#endif

+#ifdef SSL_OP_NO_TLSv1_2

+    if (tls_ver_max < TLS1_2_VERSION)

+    {

+        sslopt |= SSL_OP_NO_TLSv1_2;

+    }

+#endif

+    SSL_CTX_set_options(ctx, sslopt);

+

+    return 1;

+}

+#endif /* SSL_CTX_set_max_proto_version */

+

 #endif /* OPENSSL_COMPAT_H_ */

@@ -622,7 +622,10 @@ init_ssl(const struct options *options, struct tls_root_ctx *new_ctx)

      * cipher restrictions before loading certificates */

     tls_ctx_restrict_ciphers(new_ctx, options->cipher_list);

-    tls_ctx_set_options(new_ctx, options->ssl_flags);

+    if (!tls_ctx_set_options(new_ctx, options->ssl_flags))

+    {

+        goto err;

+    }

     if (options->pkcs12_file)

     {

@@ -162,8 +162,10 @@ bool tls_ctx_initialised(struct tls_root_ctx *ctx);

  *

  * @param ctx           TLS context to set options on

  * @param ssl_flags     SSL flags to set

+ *

+ * @return true on success, false otherwise.

  */

-void tls_ctx_set_options(struct tls_root_ctx *ctx, unsigned int ssl_flags);

+bool tls_ctx_set_options(struct tls_root_ctx *ctx, unsigned int ssl_flags);

 /**

  * Restrict the list of ciphers that can be used within the TLS context.

@@ -206,9 +206,10 @@ key_state_export_keying_material(struct key_state_ssl *ssl,

 {

 }

-void

+bool

 tls_ctx_set_options(struct tls_root_ctx *ctx, unsigned int ssl_flags)

 {

+    return true;

 }

 static const char *

@@ -206,16 +206,65 @@ info_callback(INFO_CALLBACK_SSL_CONST SSL *s, int where, int ret)

 int

 tls_version_max(void)

 {

-#if defined(SSL_OP_NO_TLSv1_2)

+#if defined(TLS1_2_VERSION) || defined(SSL_OP_NO_TLSv1_2)

     return TLS_VER_1_2;

-#elif defined(SSL_OP_NO_TLSv1_1)

+#elif defined(TLS1_1_VERSION) || defined(SSL_OP_NO_TLSv1_1)

     return TLS_VER_1_1;

 #else

     return TLS_VER_1_0;

 #endif

 }

-void

+/** Convert internal version number to openssl version number */

+static int

+openssl_tls_version(int ver)

+{

+    if (ver == TLS_VER_1_0)

+    {

+        return TLS1_VERSION;

+    }

+    else if (ver == TLS_VER_1_1)

+    {

+        return TLS1_1_VERSION;

+    }

+    else if (ver == TLS_VER_1_2)

+    {

+        return TLS1_2_VERSION;

+    }

+    return 0;

+}

+

+static bool

+tls_ctx_set_tls_versions(struct tls_root_ctx *ctx, unsigned int ssl_flags)

+{

+    int tls_ver_min = openssl_tls_version(

+        (ssl_flags >> SSLF_TLS_VERSION_MIN_SHIFT) & SSLF_TLS_VERSION_MIN_MASK);

+    int tls_ver_max = openssl_tls_version(

+        (ssl_flags >> SSLF_TLS_VERSION_MAX_SHIFT) & SSLF_TLS_VERSION_MAX_MASK);

+

+    if (!tls_ver_min)

+    {

+        /* Enforce at least TLS 1.0 */

+        int cur_min = SSL_CTX_get_min_proto_version(ctx->ctx);

+        tls_ver_min = cur_min < TLS1_VERSION ? TLS1_VERSION : cur_min;

+    }

+

+    if (!SSL_CTX_set_min_proto_version(ctx->ctx, tls_ver_min))

+    {

+        msg(D_TLS_ERRORS, "%s: failed to set minimum TLS version", __func__);

+        return false;

+    }

+

+    if (tls_ver_max && !SSL_CTX_set_max_proto_version(ctx->ctx, tls_ver_max))

+    {

+        msg(D_TLS_ERRORS, "%s: failed to set maximum TLS version", __func__);

+        return false;

+    }

+

+    return true;

+}

+

+bool

 tls_ctx_set_options(struct tls_root_ctx *ctx, unsigned int ssl_flags)

 {

     ASSERT(NULL != ctx);

@@ -223,41 +272,18 @@ tls_ctx_set_options(struct tls_root_ctx *ctx, unsigned int ssl_flags)

     /* default certificate verification flags */

     int flags = SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT;

-    /* process SSL options including minimum TLS version we will accept from peer */

-    {

-        long sslopt = SSL_OP_SINGLE_DH_USE | SSL_OP_NO_TICKET | SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3;

-        int tls_ver_max = TLS_VER_UNSPEC;

-        const int tls_ver_min =

-            (ssl_flags >> SSLF_TLS_VERSION_MIN_SHIFT) & SSLF_TLS_VERSION_MIN_MASK;

-

-        tls_ver_max =

-            (ssl_flags >> SSLF_TLS_VERSION_MAX_SHIFT) & SSLF_TLS_VERSION_MAX_MASK;

-        if (tls_ver_max <= TLS_VER_UNSPEC)

-        {

-            tls_ver_max = tls_version_max();

-        }

-

-        if (tls_ver_min > TLS_VER_1_0 || tls_ver_max < TLS_VER_1_0)

-        {

-            sslopt |= SSL_OP_NO_TLSv1;

-        }

-#ifdef SSL_OP_NO_TLSv1_1

-        if (tls_ver_min > TLS_VER_1_1 || tls_ver_max < TLS_VER_1_1)

-        {

-            sslopt |= SSL_OP_NO_TLSv1_1;

-        }

-#endif

-#ifdef SSL_OP_NO_TLSv1_2

-        if (tls_ver_min > TLS_VER_1_2 || tls_ver_max < TLS_VER_1_2)

-        {

-            sslopt |= SSL_OP_NO_TLSv1_2;

-        }

-#endif

+    /* process SSL options */

+    long sslopt = SSL_OP_SINGLE_DH_USE | SSL_OP_NO_TICKET;

 #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE

-        sslopt |= SSL_OP_CIPHER_SERVER_PREFERENCE;

+    sslopt |= SSL_OP_CIPHER_SERVER_PREFERENCE;

 #endif

-        sslopt |= SSL_OP_NO_COMPRESSION;

-        SSL_CTX_set_options(ctx->ctx, sslopt);

+    sslopt |= SSL_OP_NO_COMPRESSION;

+

+    SSL_CTX_set_options(ctx->ctx, sslopt);

+

+    if (!tls_ctx_set_tls_versions(ctx, ssl_flags))

+    {

+        return false;

     }

 #ifdef SSL_MODE_RELEASE_BUFFERS

@@ -280,6 +306,8 @@ tls_ctx_set_options(struct tls_root_ctx *ctx, unsigned int ssl_flags)

     SSL_CTX_set_verify(ctx->ctx, flags, verify_callback);

     SSL_CTX_set_info_callback(ctx->ctx, info_callback);

+

+    return true;

 }

 void