Merge branch 'maint-20' into maint

* maint-20:
  Updated OTP version
  Prepare release
  ssh: Special treatment of OpenSSH clients >= 7.2 rsa-sha2-* public keys

4 files changed, 35 insertions, 11 deletions

diff --git a/lib/ssh/doc/src/notes.xml b/lib/ssh/doc/src/notes.xml
index 4c8cbab858..3a2f55a487 100644
--- a/lib/ssh/doc/src/notes.xml
+++ b/lib/ssh/doc/src/notes.xml
@@ -30,6 +30,23 @@
     <file>notes.xml</file>
   </header>
 
+<section><title>Ssh 4.6.4</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix problem with OpenSSH 7.2 (and later) clients that has
+	    used sha1 instead of sha2 for rsa-sha-256/512 user's
+	    public keys.</p>
+          <p>
+	    Own Id: OTP-14827 Aux Id: ERL-531 </p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
 <section><title>Ssh 4.6.3</title>
 
     <section><title>Fixed Bugs and Malfunctions</title>
diff --git a/lib/ssh/src/ssh_auth.erl b/lib/ssh/src/ssh_auth.erl
index 894877f8bf..03d264745b 100644
--- a/lib/ssh/src/ssh_auth.erl
+++ b/lib/ssh/src/ssh_auth.erl
@@ -304,11 +304,10 @@ handle_userauth_request(#ssh_msg_userauth_request{user = User,
 							   SigWLen/binary>>
 						 }, 
 			SessionId, 
-			#ssh{opts = Opts,
-			     userauth_supported_methods = Methods} = Ssh) ->
+			#ssh{userauth_supported_methods = Methods} = Ssh) ->
     
     case verify_sig(SessionId, User, "ssh-connection", 
-		    BAlg, KeyBlob, SigWLen, Opts) of
+		    BAlg, KeyBlob, SigWLen, Ssh) of
 	true ->
 	    {authorized, User, 
 	     ssh_transport:ssh_packet(
@@ -518,7 +517,7 @@ pre_verify_sig(User, KeyBlob, Opts) ->
 	    false
     end.
 
-verify_sig(SessionId, User, Service, AlgBin, KeyBlob, SigWLen, Opts) ->
+verify_sig(SessionId, User, Service, AlgBin, KeyBlob, SigWLen, #ssh{opts = Opts} = Ssh) ->
     try
         Alg = binary_to_list(AlgBin),
         {KeyCb,KeyCbOpts} = ?GET_OPT(key_cb, Opts),
@@ -529,7 +528,7 @@ verify_sig(SessionId, User, Service, AlgBin, KeyBlob, SigWLen, Opts) ->
         <<?UINT32(AlgSigLen), AlgSig:AlgSigLen/binary>> = SigWLen,
         <<?UINT32(AlgLen), _Alg:AlgLen/binary,
           ?UINT32(SigLen), Sig:SigLen/binary>> = AlgSig,
-        ssh_transport:verify(PlainText, ssh_transport:sha(Alg), Sig, Key)
+        ssh_transport:verify(PlainText, ssh_transport:sha(Alg), Sig, Key, Ssh)
     catch
 	_:_ ->
 	    false
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index 90a94a7e86..154894cda8 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -51,7 +51,7 @@
 	 extract_public_key/1,
 	 ssh_packet/2, pack/2,
          valid_key_sha_alg/2,
-	 sha/1, sign/3, verify/4]).
+	 sha/1, sign/3, verify/5]).
 
 %%% For test suites
 -export([pack/3]).
@@ -825,7 +825,7 @@ extract_public_key(#{engine:=_, key_id:=_, algorithm:=Alg} = M) ->
 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
+            case verify(Digest, sha(Alg#alg.hkey), Signature, PublicKey, SSH) of
                 false ->
                     {error, bad_signature};
                 true ->
@@ -1288,7 +1288,7 @@ mk_dss_sig(DerSignature) ->
     <<R:160/big-unsigned-integer, S:160/big-unsigned-integer>>.
 
 
-verify(PlainText, HashAlg, Sig, {_,  #'Dss-Parms'{}} = Key) ->
+verify(PlainText, HashAlg, Sig, {_,  #'Dss-Parms'{}} = Key, _) ->
     case Sig of
         <<R:160/big-unsigned-integer, S:160/big-unsigned-integer>> ->
             Signature = public_key:der_encode('Dss-Sig-Value', #'Dss-Sig-Value'{r = R, s = S}),
@@ -1296,7 +1296,7 @@ verify(PlainText, HashAlg, Sig, {_,  #'Dss-Parms'{}} = Key) ->
         _ ->
             false
     end;
-verify(PlainText, HashAlg, Sig, {#'ECPoint'{},_} = Key) ->
+verify(PlainText, HashAlg, Sig, {#'ECPoint'{},_} = Key, _) ->
     case Sig of
         <<?UINT32(Rlen),R:Rlen/big-signed-integer-unit:8,
           ?UINT32(Slen),S:Slen/big-signed-integer-unit:8>> ->
@@ -1306,7 +1306,15 @@ verify(PlainText, HashAlg, Sig, {#'ECPoint'{},_} = Key) ->
         _ ->
             false
     end;
-verify(PlainText, HashAlg, Sig, Key) ->
+
+verify(PlainText, HashAlg, Sig, #'RSAPublicKey'{}=Key, #ssh{role = server,
+                                                            c_version = "SSH-2.0-OpenSSH_7."++_})
+  when HashAlg == sha256; HashAlg == sha512 ->
+    %% Public key signing bug in in OpenSSH >= 7.2
+    public_key:verify(PlainText, HashAlg, Sig, Key)
+        orelse public_key:verify(PlainText, sha, Sig, Key);
+
+verify(PlainText, HashAlg, Sig, Key, _) ->
     public_key:verify(PlainText, HashAlg, Sig, Key).
 
 
diff --git a/lib/ssh/vsn.mk b/lib/ssh/vsn.mk
index 668d2358c0..004db6e3a2 100644
--- a/lib/ssh/vsn.mk
+++ b/lib/ssh/vsn.mk
@@ -1,5 +1,5 @@
 #-*-makefile-*-   ; force emacs to enter makefile-mode
 
-SSH_VSN = 4.6.3
+SSH_VSN = 4.6.4
 
 APP_VSN    = "ssh-$(SSH_VSN)"