Merge branch 'hans/ssh/fix_ext_info/OTP-15413' into maint

* hans/ssh/fix_ext_info/OTP-15413:
  ssh: Fix ssh_options checking for ext_info
  ssh: Fix SSH_MSG_EXT_INFO bug for OTP SSH as server
  ssh: Fix SSH_MSG_EXT_INFO bug for OTP SSH as client

3 files changed, 11 insertions, 8 deletions

diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index 4b41c10cbb..30eafc2f2a 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -983,6 +983,10 @@ handle_event(_, #ssh_msg_userauth_info_request{}, {userauth_keyboard_interactive
 
 %%% ######## {connected, client|server} ####
 
+%% Skip ext_info messages in connected state (for example from OpenSSH >= 7.7)
+handle_event(_, #ssh_msg_ext_info{}, {connected,_Role}, D) ->
+    {keep_state, D};
+
 handle_event(_, {#ssh_msg_kexinit{},_}, {connected,Role}, D0) ->
     {KeyInitMsg, SshPacket, Ssh} = ssh_transport:key_exchange_init_msg(D0#data.ssh_params),
     D = D0#data{ssh_params = Ssh,
diff --git a/lib/ssh/src/ssh_options.erl b/lib/ssh/src/ssh_options.erl
index bc9f2156bc..bc9b0b6eda 100644
--- a/lib/ssh/src/ssh_options.erl
+++ b/lib/ssh/src/ssh_options.erl
@@ -452,12 +452,6 @@ default(client) ->
             class => user_options
            },
 
-      {pref_public_key_algs, def} =>
-          #{default => ssh_transport:default_algorithms(public_key),
-            chk => fun check_pref_public_key_algs/1,
-            class => user_options
-           },
-
       {dh_gex_limits, def} =>
           #{default => {1024, 6144, 8192},      % FIXME: Is this true nowadays?
             chk => fun({Min,I,Max}) ->
@@ -523,6 +517,12 @@ default(common) ->
              class => user_options
             },
 
+      {pref_public_key_algs, def} =>
+          #{default => ssh_transport:default_algorithms(public_key),
+            chk => fun check_pref_public_key_algs/1,
+            class => user_options
+           },
+
        {preferred_algorithms, def} =>
            #{default => ssh:default_algorithms(),
              chk => fun check_preferred_algorithms/1,
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index c5b0704925..7424c9bcaf 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -759,8 +759,7 @@ ext_info_message(#ssh{role=server,
                       send_ext_info=true,
                       opts = Opts} = Ssh0) ->
     AlgsList = lists:map(fun erlang:atom_to_list/1,
-                         proplists:get_value(public_key,
-                                             ?GET_OPT(preferred_algorithms, Opts))),
+                         ?GET_OPT(pref_public_key_algs, Opts)),
     Msg = #ssh_msg_ext_info{nr_extensions = 1,
                             data = [{"server-sig-algs", string:join(AlgsList,",")}]
                            },