Merge branch 'hans/ssh/rsa-sha2-star_hostkey'

5 files changed, 34 insertions, 42 deletions

diff --git a/lib/public_key/src/pubkey_ssh.erl b/lib/public_key/src/pubkey_ssh.erl
index 6974afa992..9bda76d670 100644
--- a/lib/public_key/src/pubkey_ssh.erl
+++ b/lib/public_key/src/pubkey_ssh.erl
@@ -408,10 +408,11 @@ comma_list_encode([Option | Rest], Acc) ->
     comma_list_encode(Rest, Acc ++ "," ++ Option).
 
 
-%% An experimental fix adding the signature algorithm name as the last element in a tuple...
-
 ssh2_pubkey_encode(#'RSAPublicKey'{modulus = N, publicExponent = E}) ->
     ssh2_pubkey_encode({#'RSAPublicKey'{modulus = N, publicExponent = E}, 'ssh-rsa'});
+
+ssh2_pubkey_encode({Key, 'rsa-sha2-256'}) -> ssh2_pubkey_encode({Key, 'ssh-rsa'});
+ssh2_pubkey_encode({Key, 'rsa-sha2-512'}) -> ssh2_pubkey_encode({Key, 'ssh-rsa'});
 ssh2_pubkey_encode({#'RSAPublicKey'{modulus = N, publicExponent = E}, SignAlg}) ->
     SignAlgName = list_to_binary(atom_to_list(SignAlg)),
     StrLen = size(SignAlgName),
@@ -448,16 +449,12 @@ ssh2_pubkey_encode(Key={#'ECPoint'{point = Q}, {namedCurve,OID}}) ->
 ssh2_pubkey_decode(Bin = <<?UINT32(Len), Type:Len/binary, _/binary>>) ->
     ssh2_pubkey_decode(Type, Bin).
 
-%% An experimental fix with the Signature Algorithm Name
-ssh2_pubkey_decode(SignAlgName,
+ssh2_pubkey_decode(<<"rsa-sha2-256">>, Bin) -> ssh2_pubkey_decode(<<"ssh-rsa">>, Bin);
+ssh2_pubkey_decode(<<"rsa-sha2-512">>, Bin) -> ssh2_pubkey_decode(<<"ssh-rsa">>, Bin);
+ssh2_pubkey_decode(<<"ssh-rsa">>,
 		   <<?UINT32(Len),   _:Len/binary,
 		     ?UINT32(SizeE), E:SizeE/binary,
-		     ?UINT32(SizeN), N:SizeN/binary>>)
-  when SignAlgName == <<"ssh-rsa">> ;
-       SignAlgName == <<"rsa-sha2-256">> ;
-       SignAlgName == <<"rsa-sha2-384">> ;
-       SignAlgName == <<"rsa-sha2-512">> 
-       ->
+		     ?UINT32(SizeN), N:SizeN/binary>>) ->
     #'RSAPublicKey'{modulus = erlint(SizeN, N),
 		    publicExponent = erlint(SizeE, E)};
 
@@ -471,6 +468,7 @@ ssh2_pubkey_decode(<<"ssh-dss">>,
      #'Dss-Parms'{p = erlint(SizeP, P),
 		  q = erlint(SizeQ, Q),
 		  g = erlint(SizeG, G)}};
+
 ssh2_pubkey_decode(<<"ecdsa-sha2-",Id/binary>>,
 		   <<?UINT32(Len), ECDSA_SHA2_etc:Len/binary,
 		     ?UINT32(SizeId), Id:SizeId/binary,
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index 6a6b9896cb..a77cfe51b5 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -1712,7 +1712,12 @@ ext_info({"server-sig-algs",SigAlgs}, D0 = #data{ssh_params=#ssh{role=client,
                     ],
     CommonAlgs = [Alg || Alg <- ServerSigAlgs,
                          lists:member(Alg, ClientSigAlgs)],
-    D0#data{ssh_params = Ssh0#ssh{userauth_pubkeys = CommonAlgs} };
+    SelectedAlgs =
+        case CommonAlgs of
+            [] -> ClientSigAlgs; % server-sig-algs value is just an advice
+            _ -> CommonAlgs
+        end,
+    D0#data{ssh_params = Ssh0#ssh{userauth_pubkeys = SelectedAlgs} };
 
 ext_info(_, D0) ->
     %% Not implemented
diff --git a/lib/ssh/src/ssh_message.erl b/lib/ssh/src/ssh_message.erl
index 609040826f..4f2eeca026 100644
--- a/lib/ssh/src/ssh_message.erl
+++ b/lib/ssh/src/ssh_message.erl
@@ -598,8 +598,8 @@ decode_kex_init(<<?DEC_BIN(Data,__0), Rest/binary>>, Acc, N) ->
 %%% Signature decode/encode
 %%%
 
-decode_signature(<<?DEC_BIN(_Alg,__0), ?UINT32(_), Signature/binary>>) ->
-    Signature.
+decode_signature(<<?DEC_BIN(Alg,__0), ?UINT32(_), Signature/binary>>) ->
+    {binary_to_list(Alg), Signature}.
 
 
 encode_signature({#'RSAPublicKey'{},Sign}, Signature) ->
diff --git a/lib/ssh/src/ssh_options.erl b/lib/ssh/src/ssh_options.erl
index 12c0190082..aebb5a7062 100644
--- a/lib/ssh/src/ssh_options.erl
+++ b/lib/ssh/src/ssh_options.erl
@@ -392,12 +392,6 @@ default(server) ->
             class => user_options
            },
 
-      {preferred_algorithms, def} =>
-          #{default => ssh:default_algorithms(),
-            chk => fun check_preferred_algorithms/1,
-            class => user_options
-           },
-
 %%%%% Undocumented
       {infofun, def} =>
           #{default => fun(_,_,_) -> void end,
@@ -436,26 +430,11 @@ default(client) ->
            },
 
       {pref_public_key_algs, def} =>
-          #{default => ssh_transport:default_algorithms(public_key) -- ['rsa-sha2-256',
-                                                                        'rsa-sha2-512'],
+          #{default => ssh_transport:default_algorithms(public_key),
             chk => fun check_pref_public_key_algs/1,
             class => user_options
            },
 
-      {preferred_algorithms, def} =>
-          #{default => [{K,Vs} || {K,Vs0} <- ssh:default_algorithms(),
-                                  Vs <- [case K of
-                                             public_key -> 
-                                                 Vs0 -- ['rsa-sha2-256',
-                                                         'rsa-sha2-512'];
-                                             _ ->
-                                                 Vs0
-                                         end]
-                       ],
-            chk => fun check_preferred_algorithms/1,
-            class => user_options
-           },
-
       {dh_gex_limits, def} =>
           #{default => {1024, 6144, 8192},      % FIXME: Is this true nowadays?
             chk => fun({Min,I,Max}) ->
@@ -521,6 +500,12 @@ default(common) ->
              class => user_options
             },
 
+       {preferred_algorithms, def} =>
+           #{default => ssh:default_algorithms(),
+             chk => fun check_preferred_algorithms/1,
+             class => user_options
+            },
+
        {id_string, def} => 
            #{default => undefined, % FIXME: see ssh_transport:ssh_vsn/0
              chk => fun(random) -> 
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index 1a15798080..412f5de9de 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -776,16 +776,20 @@ extract_public_key(#'ECPrivateKey'{parameters = {namedCurve,OID},
     {#'ECPoint'{point=Q}, {namedCurve,OID}}.
 
 
-verify_host_key(#ssh{algorithms=Alg}=SSH, PublicKey, Digest, Signature) ->
-    case verify(Digest, sha(Alg#alg.hkey), Signature, PublicKey) of
-	false ->
-	    {error, bad_signature};
-	true ->
-	    known_host_key(SSH, PublicKey, public_algo(PublicKey))
+verify_host_key(#ssh{algorithms=Alg}=SSH, PublicKey, Digest, {AlgStr,Signature}) ->
+    case atom_to_list(Alg#alg.hkey) of
+        AlgStr ->
+            case verify(Digest, sha(Alg#alg.hkey), Signature, PublicKey) of
+                false ->
+                    {error, bad_signature};
+                true ->
+                    known_host_key(SSH, PublicKey, public_algo(PublicKey))
+            end;
+        _ ->
+            {error, bad_signature_name}
     end.
 
 
-
 accepted_host(Ssh, PeerName, Public, Opts) ->
     case ?GET_OPT(silently_accept_hosts, Opts) of