vtls: add options to specify range of enabled TLS versions

This commit introduces the CURL_SSLVERSION_MAX_* constants as well as
the --tls-max option of the curl tool.

Closes https://github.com/curl/curl/pull/1166

1 files changed, 120 insertions, 25 deletions

diff --git a/lib/vtls/darwinssl.c b/lib/vtls/darwinssl.c
index 25a8ab8b6..26ea04cbb 100644
--- a/lib/vtls/darwinssl.c
+++ b/lib/vtls/darwinssl.c
@@ -1044,6 +1044,109 @@ CF_INLINE bool is_file(const char *filename)
   return false;
 }
 
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+static CURLcode darwinssl_version_from_curl(long *darwinver, long version)
+{
+  switch(ssl_version) {
+    case CURL_SSLVERSION_TLSv1_0:
+      *darwinver = kTLSProtocol1;
+      return CURLE_OK;
+    case CURL_SSLVERSION_TLSv1_1:
+      *darwinver = kTLSProtocol11;
+      return CURLE_OK;
+    case CURL_SSLVERSION_TLSv1_2:
+      *darwinver = kTLSProtocol12;
+      return CURLE_OK;
+    case CURL_SSLVERSION_TLSv1_3:
+      break;
+  }
+  return CURLE_SSL_CONNECT_ERROR;
+}
+#endif
+
+static CURLcode
+set_ssl_version_min_max(struct connectdata *conn, int sockindex)
+{
+  struct Curl_easy *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  long ssl_version = SSL_CONN_CONFIG(version);
+  long ssl_version_max = SSL_CONN_CONFIG(version_max);
+
+  switch(ssl_version) {
+    case CURL_SSLVERSION_DEFAULT:
+    case CURL_SSLVERSION_TLSv1:
+      ssl_version = CURL_SSLVERSION_TLSv1_0;
+      ssl_version_max = CURL_SSLVERSION_MAX_TLSv1_2;
+      break;
+  }
+
+  switch(ssl_version_max) {
+    case CURL_SSLVERSION_MAX_NONE:
+      ssl_version_max = ssl_version << 16;
+      break;
+    case CURL_SSLVERSION_MAX_DEFAULT:
+      ssl_version_max = CURL_SSLVERSION_MAX_TLSv1_2;
+      break;
+  }
+
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+  if(SSLSetProtocolVersionMax != NULL) {
+    SSLProtocol darwin_ver_min = kTLSProtocol1;
+    SSLProtocol darwin_ver_max = kTLSProtocol1;
+    CURLcode result = darwinssl_version_from_curl(&darwin_ver_min,
+                                                  ssl_version);
+    if(result) {
+      failf(data, "unsupported min version passed via CURLOPT_SSLVERSION");
+      return result;
+    }
+    result = darwinssl_version_from_curl(&darwin_ver_max,
+                                         ssl_version_max >> 16);
+    if(result) {
+      failf(data, "unsupported max version passed via CURLOPT_SSLVERSION");
+      return result;
+    }
+
+    (void)SSLSetProtocolVersionMin(connssl->ssl_ctx, darwin_ver_min);
+    (void)SSLSetProtocolVersionMax(connssl->ssl_ctx, darwin_ver_max);
+    return result;
+  }
+  else {
+#if CURL_SUPPORT_MAC_10_8
+    long i = ssl_version;
+    (void)SSLSetProtocolVersionEnabled(connssl->ssl_ctx,
+                                       kSSLProtocolAll,
+                                       false);
+    for(; i <= (ssl_version_max >> 16); i++) {
+      switch(i) {
+        case CURL_SSLVERSION_TLSv1_0:
+          (void)SSLSetProtocolVersionEnabled(connssl->ssl_ctx,
+                                            kTLSProtocol1,
+                                            true);
+          break;
+        case CURL_SSLVERSION_TLSv1_1:
+          (void)SSLSetProtocolVersionEnabled(connssl->ssl_ctx,
+                                            kTLSProtocol11,
+                                            true);
+          break;
+        case CURL_SSLVERSION_TLSv1_2:
+          (void)SSLSetProtocolVersionEnabled(connssl->ssl_ctx,
+                                            kTLSProtocol12,
+                                            true);
+          break;
+        case CURL_SSLVERSION_TLSv1_3:
+          failf(data, "DarwinSSL: TLS 1.3 is not yet supported");
+          return CURLE_SSL_CONNECT_ERROR;
+      }
+    }
+    return CURLE_OK;
+#endif  /* CURL_SUPPORT_MAC_10_8 */
+  }
+#endif  /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
+  failf(data, "DarwinSSL: cannot set SSL protocol");
+  return CURLE_SSL_CONNECT_ERROR;
+}
+
+
 static CURLcode darwinssl_connect_step1(struct connectdata *conn,
                                         int sockindex)
 {
@@ -1113,20 +1216,15 @@ static CURLcode darwinssl_connect_step1(struct connectdata *conn,
       (void)SSLSetProtocolVersionMax(connssl->ssl_ctx, kTLSProtocol12);
       break;
     case CURL_SSLVERSION_TLSv1_0:
-      (void)SSLSetProtocolVersionMin(connssl->ssl_ctx, kTLSProtocol1);
-      (void)SSLSetProtocolVersionMax(connssl->ssl_ctx, kTLSProtocol1);
-      break;
     case CURL_SSLVERSION_TLSv1_1:
-      (void)SSLSetProtocolVersionMin(connssl->ssl_ctx, kTLSProtocol11);
-      (void)SSLSetProtocolVersionMax(connssl->ssl_ctx, kTLSProtocol11);
-      break;
     case CURL_SSLVERSION_TLSv1_2:
-      (void)SSLSetProtocolVersionMin(connssl->ssl_ctx, kTLSProtocol12);
-      (void)SSLSetProtocolVersionMax(connssl->ssl_ctx, kTLSProtocol12);
-      break;
     case CURL_SSLVERSION_TLSv1_3:
-      failf(data, "DarwinSSL: TLS 1.3 is not yet supported");
-      return CURLE_SSL_CONNECT_ERROR;
+      {
+        CURLcode result = set_ssl_version_min_max(conn, sockindex);
+        if(result != CURLE_OK)
+          return result;
+        break;
+      }
     case CURL_SSLVERSION_SSLv3:
       err = SSLSetProtocolVersionMin(connssl->ssl_ctx, kSSLProtocol3);
       if(err != noErr) {
@@ -1167,23 +1265,15 @@ static CURLcode darwinssl_connect_step1(struct connectdata *conn,
                                          true);
       break;
     case CURL_SSLVERSION_TLSv1_0:
-      (void)SSLSetProtocolVersionEnabled(connssl->ssl_ctx,
-                                         kTLSProtocol1,
-                                         true);
-      break;
     case CURL_SSLVERSION_TLSv1_1:
-      (void)SSLSetProtocolVersionEnabled(connssl->ssl_ctx,
-                                         kTLSProtocol11,
-                                         true);
-      break;
     case CURL_SSLVERSION_TLSv1_2:
-      (void)SSLSetProtocolVersionEnabled(connssl->ssl_ctx,
-                                         kTLSProtocol12,
-                                         true);
-      break;
     case CURL_SSLVERSION_TLSv1_3:
-      failf(data, "DarwinSSL: TLS 1.3 is not yet supported");
-      return CURLE_SSL_CONNECT_ERROR;
+      {
+        CURLcode result = set_ssl_version_min_max(conn, sockindex);
+        if(result != CURLE_OK)
+          return result;
+        break;
+      }
     case CURL_SSLVERSION_SSLv3:
       err = SSLSetProtocolVersionEnabled(connssl->ssl_ctx,
                                          kSSLProtocol3,
@@ -1209,6 +1299,11 @@ static CURLcode darwinssl_connect_step1(struct connectdata *conn,
 #endif  /* CURL_SUPPORT_MAC_10_8 */
   }
 #else
+  if(conn->ssl_config.version_max != CURL_SSLVERSION_MAX_NONE) {
+    failf(data, "Your version of the OS does not support to set maximum"
+                " SSL/TLS version");
+    return CURLE_SSL_CONNECT_ERROR;
+  }
   (void)SSLSetProtocolVersionEnabled(connssl->ssl_ctx, kSSLProtocolAll, false);
   switch(conn->ssl_config.version) {
   case CURL_SSLVERSION_DEFAULT: