Improved certificate extension handling

Added the functionality so that the verification fun will be called
when a certificate is considered valid by the path validation to allow
access to eachs certificate in the path to the user application.

Removed clause that only check that a extension is not critical,
it does alter the verification rusult only withholds information from
the application.

Try to verify subject-AltName, if unable to verify it let
application try.

4 files changed, 46 insertions, 37 deletions

diff --git a/lib/ssl/doc/src/ssl.xml b/lib/ssl/doc/src/ssl.xml
index 0f3054aec3..d5b7253ef3 100644
--- a/lib/ssl/doc/src/ssl.xml
+++ b/lib/ssl/doc/src/ssl.xml
@@ -202,16 +202,19 @@
 	<p>The verification fun should be defined as:</p>
 
 	<code>
-	  fun(OtpCert :: #'OtpCertificate'{},
-	      Event :: {bad_cert, Reason :: atom()} |
-	      {extension, #'Extension'{}}, InitialUserState :: term()) ->
-	          {valid, UserState :: term()} | {fail, Reason :: term()} |
-	          {unknown, UserState :: term()}.
+fun(OtpCert :: #'OtpCertificate'{}, Event :: {bad_cert, Reason :: atom()} |
+	     {extension, #'Extension'{}}, InitialUserState :: term()) ->
+	{valid, UserState :: term()} | {fail, Reason :: term()} |
+	{unknown, UserState :: term()}.
 	</code>
 
 	<p>The verify fun will be called during the X509-path
 	validation when an error or an extension unknown to the ssl
-	application is encountered. See
+	application is encountered. Additionally it will be called
+	when a certificate is considered valid by the path validation
+	to allow access to each certificate in the path to the user
+	application.
+	See
 	<seealso marker="public_key:application">public_key(3)</seealso>
 	for definition of #'OtpCertificate'{} and #'Extension'{}.</p>
 
@@ -229,34 +232,32 @@
 	<p>The default verify_fun option in verify_peer mode:</p>
 
       <code>
-	{fun(_,{bad_cert, _} = Reason, _) ->
-		 {fail, Reason};
-	    (_,{extension, _}, UserState) ->
-		 {unknown, UserState}
-	 end, []}
+{fun(_,{bad_cert, _} = Reason, _) ->
+	 {fail, Reason};
+    (_,{extension, _}, UserState) ->
+	 {unknown, UserState};
+    (_, valid, UserState) ->
+	 {valid, UserState}
+ end, []}
       </code>
 
       <p>The default verify_fun option in verify_none mode:</p>
 
        <code>
-	{fun(_,{bad_cert, unknown_ca}, UserState) ->
-		 {valid, UserState};
-	    (_,{bad_cert, _} = Reason, _) ->
-		 {fail, Reason};
-	    (_,{extension, _}, UserState) ->
-		 {unknown, UserState}
-	 end, []}
+{fun(_,{bad_cert, unknown_ca}, UserState) ->
+	 {valid, UserState};
+    (_,{bad_cert, _} = Reason, _) ->
+	 {fail, Reason};
+    (_,{extension, _}, UserState) ->
+	 {unknown, UserState};
+    (_, valid, UserState) ->
+	 {valid, UserState}
+ end, []}
       </code>
 
-      <p> Possible path validation errors:
-       {bad_cert, cert_expired},
-       {bad_cert, invalid_issuer},
-       {bad_cert, invalid_signature},
-       {bad_cert, unknown_ca},
-       {bad_cert, name_not_permitted},
-       {bad_cert, missing_basic_constraint},
-       {bad_cert, invalid_key_usage},
-       {bad_cert, invalid_subject_altname}</p>
+<p>Possible path validation errors: </p>
+
+<p> {bad_cert, cert_expired}, {bad_cert, invalid_issuer}, {bad_cert, invalid_signature}, {bad_cert, unknown_ca}, {bad_cert, name_not_permitted}, {bad_cert, missing_basic_constraint}, {bad_cert, invalid_key_usage}</p>
       </item>
 
     </taglist>
diff --git a/lib/ssl/src/ssl.erl b/lib/ssl/src/ssl.erl
index cc01b35b64..12dffb413c 100644
--- a/lib/ssl/src/ssl.erl
+++ b/lib/ssl/src/ssl.erl
@@ -535,7 +535,9 @@ handle_options(Opts0, _Role) ->
 	    (_,{bad_cert, _} = Reason, _) ->
 		 {fail, Reason};
 	    (_,{extension, _}, UserState) ->
-		 {unknown, UserState}
+		 {unknown, UserState};
+	    (_, valid, UserState) ->
+		 {valid, UserState}
 	 end, []},
 
     UserFailIfNoPeerCert = handle_option(fail_if_no_peer_cert, Opts, false),
@@ -631,7 +633,9 @@ validate_option(verify_fun, Fun) when is_function(Fun) ->
 		     {fail, Reason}
 	     end;
 	(_,{extension, _}, UserState) ->
-	     {unknown, UserState}
+	     {unknown, UserState};
+	(_, valid, UserState) ->
+	     {valid, UserState}
      end, Fun};
 validate_option(verify_fun, {Fun, _} = Value) when is_function(Fun) ->
    Value;
diff --git a/lib/ssl/src/ssl_certificate.erl b/lib/ssl/src/ssl_certificate.erl
index 6cf57ced81..206024315e 100644
--- a/lib/ssl/src/ssl_certificate.erl
+++ b/lib/ssl/src/ssl_certificate.erl
@@ -34,7 +34,6 @@
 -export([trusted_cert_and_path/2,
 	 certificate_chain/2, 
 	 file_to_certificats/1,
-	 %validate_extensions/6,
 	 validate_extension/3,
 	 is_valid_extkey_usage/2,
 	 is_valid_key_usage/2,
@@ -118,8 +117,7 @@ file_to_certificats(File) ->
 %% Description:  Validates ssl/tls specific extensions
 %%--------------------------------------------------------------------
 validate_extension(_,{extension, #'Extension'{extnID = ?'id-ce-extKeyUsage',
-					      extnValue = KeyUse,
-					      critical = true}}, Role) ->
+					      extnValue = KeyUse}}, Role) ->
     case is_valid_extkey_usage(KeyUse, Role) of
 	true ->
 	    {valid, Role};
@@ -128,8 +126,10 @@ validate_extension(_,{extension, #'Extension'{extnID = ?'id-ce-extKeyUsage',
     end;
 validate_extension(_, {bad_cert, _} = Reason, _) ->
     {fail, Reason};
-validate_extension(_, _, Role) ->
-    {unknown, Role}.
+validate_extension(_, {extension, _}, Role) ->
+    {unknown, Role};
+validate_extension(_, valid, Role) ->
+    {valid, Role}.
 
 %%--------------------------------------------------------------------
 -spec is_valid_key_usage(list(), term()) -> boolean().
diff --git a/lib/ssl/test/ssl_basic_SUITE.erl b/lib/ssl/test/ssl_basic_SUITE.erl
index 1e96880801..3cb9337775 100644
--- a/lib/ssl/test/ssl_basic_SUITE.erl
+++ b/lib/ssl/test/ssl_basic_SUITE.erl
@@ -2860,7 +2860,9 @@ unknown_server_ca_fail(Config) when is_list(Config) ->
     FunAndState =  {fun(_,{bad_cert, _} = Reason, _) ->
 			    {fail, Reason};
 		       (_,{extension, _}, UserState) ->
-			    {unknown, UserState}
+			    {unknown, UserState};
+		       (_, valid, UserState) ->
+			    {valid, UserState}
 		    end, []},
 
     Client = ssl_test_lib:start_client_error([{node, ClientNode}, {port, Port},
@@ -2926,7 +2928,9 @@ unknown_server_ca_accept_verify_peer(Config) when is_list(Config) ->
 		       (_,{bad_cert, _} = Reason, _) ->
 			    {fail, Reason};
 		       (_,{extension, _}, UserState) ->
-			    {unknown, UserState}
+			    {unknown, UserState};
+		       (_, valid, UserState) ->
+			    {valid, UserState}
 		    end, []},
 
     Client = ssl_test_lib:start_client([{node, ClientNode}, {port, Port},
@@ -3095,7 +3099,7 @@ session_cache_process_mnesia(suite) ->
 session_cache_process_mnesia(Config) when is_list(Config) -> 
     session_cache_process(mnesia,Config).
 
-session_cache_process(Type,Config) when is_list(Config) -> 
+session_cache_process(_Type,Config) when is_list(Config) ->
     reuse_session(Config).
 
 init([Type]) ->