Remove check for negotiated DH group in TLS client

The server may not support the supported groups
extension and choose an arbitrary group. RFC 7919
permits clients to continue if the group is
acceptable under local policy, which we do now.

1 files changed, 0 insertions, 29 deletions

diff --git a/src/lib/tls/msg_client_kex.cpp b/src/lib/tls/msg_client_kex.cpp
index 1c3950a03..3291b6eb5 100644
--- a/src/lib/tls/msg_client_kex.cpp
+++ b/src/lib/tls/msg_client_kex.cpp
@@ -101,35 +101,6 @@ Client_Key_Exchange::Client_Key_Exchange(Handshake_IO& io,
             throw Decoding_Error("Bad params size for DH key exchange");
 
          /*
-          * If we offer ffdhe groups in the client hello,
-          * p and g must match one of these groups.
-          */
-         std::vector<std::string> allowed_groups = policy.allowed_groups();
-         bool server_sent_requested_group = false;
-
-         if(!allowed_groups.empty())
-            {
-            for(const auto& allowed_group : allowed_groups)
-               {
-               if(Supported_Groups::is_dh_group(allowed_group))
-                  {
-                  DL_Group client_group(allowed_group);
-                  if(client_group.get_p() == p && client_group.get_g() == g)
-                     {
-                     server_sent_requested_group = true;
-                     break;
-                     }
-                  }
-               }
-            }
-
-         if(!server_sent_requested_group)
-            {
-            throw TLS_Exception(Alert::INSUFFICIENT_SECURITY,
-                                "Server sent unexpected DH key for DHE exchange");
-            }
-
-         /*
          * A basic check for key validity. As we do not know q here we
          * cannot check that Y is in the right subgroup. However since
          * our key is ephemeral there does not seem to be any