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.

2 files changed, 41 insertions, 55 deletions

diff --git a/lib/public_key/src/pubkey_cert.erl b/lib/public_key/src/pubkey_cert.erl
index 7851981a30..e704c168f1 100644
--- a/lib/public_key/src/pubkey_cert.erl
+++ b/lib/public_key/src/pubkey_cert.erl
@@ -29,7 +29,7 @@
 	 validate_revoked_status/3, validate_extensions/4,
 	 normalize_general_name/1, digest_type/1, is_self_signed/1,
 	 is_issuer/2, issuer_id/2, is_fixed_dh_cert/1,
-	 verify_data/1]).
+	 verify_data/1, verify_fun/4]).
 
 -define(NULL, 0).
  
@@ -288,6 +288,35 @@ is_fixed_dh_cert(#'OTPCertificate'{tbsCertificate =
 							Extensions}}) ->
     is_fixed_dh_cert(SubjectPublicKeyInfo, extensions_list(Extensions)). 
 
+
+%%--------------------------------------------------------------------
+-spec verify_fun(#'OTPTBSCertificate'{}, {bad_cert, atom()} | {extension, #'Extension'{}}|
+		 valid, term(), fun()) -> term().
+%%
+%% Description: Gives the user application the opportunity handle path
+%% validation errors and unknown extensions and optional do other
+%% things with a validated certificate.
+%% --------------------------------------------------------------------
+verify_fun(Otpcert, Result, UserState0, VerifyFun) ->
+    case VerifyFun(Otpcert, Result, UserState0) of
+	{valid,UserState} ->
+	    UserState;
+	{fail, Reason} ->
+	    case Result of
+		{bad_cert, _} ->
+		    throw(Result);
+		_ ->
+		    throw({bad_cert, Reason})
+	    end;
+	{unknown, UserState} ->
+	    case Result of
+		{extension, #'Extension'{critical = true}} ->
+		    throw({bad_cert, unknown_critical_extension});
+		_ ->
+		  UserState
+	    end
+    end.
+
 %%--------------------------------------------------------------------
 %%% Internal functions
 %%--------------------------------------------------------------------
@@ -315,25 +344,6 @@ extensions_list(asn1_NOVALUE) ->
 extensions_list(Extensions) ->
     Extensions.
 
-verify_fun(Otpcert, Result, UserState0, VerifyFun) ->
-    case VerifyFun(Otpcert, Result, UserState0) of
-	{valid,UserState} ->
-	    UserState;
-	{fail, Reason} ->
-	    case Result of
-		{bad_cert, _} ->
-		    throw(Result);
-		_ ->
-		    throw({bad_cert, Reason})
-	    end;
-	{unknown, UserState} ->
-	    case Result of
-		{extension, #'Extension'{critical = true}} ->
-		    throw({bad_cert, unknown_critical_extension});
-		_ ->
-		  UserState
-	    end
-    end.
 
 extract_verify_data(OtpCert, DerCert) ->
     {0, Signature} = OtpCert#'OTPCertificate'.signature,
@@ -538,47 +548,21 @@ validate_extensions(OtpCert, [#'Extension'{extnID = ?'id-ce-keyUsage',
     end;
 
 validate_extensions(OtpCert, [#'Extension'{extnID = ?'id-ce-subjectAltName',
-					   extnValue = Names} = Ext | Rest],
+					   extnValue = Names,
+					   critical = true} = Ext | Rest],
 		    ValidationState, ExistBasicCon,
 		    SelfSigned, UserState0, VerifyFun)  ->
     case validate_subject_alt_names(Names) of
-	true when Names =/= [] ->
+	true  ->
 	    validate_extensions(OtpCert, Rest, ValidationState, ExistBasicCon,
 				SelfSigned, UserState0, VerifyFun);
 	false ->
-	    UserState = verify_fun(OtpCert, {bad_cert, invalid_subject_altname},
-				   UserState0, VerifyFun),
-	    validate_extensions(OtpCert, Rest, ValidationState, ExistBasicCon,
-				SelfSigned, UserState, VerifyFun);
-	other ->
 	    UserState = verify_fun(OtpCert, {extension, Ext},
 				   UserState0, VerifyFun),
 	    validate_extensions(OtpCert, Rest, ValidationState, ExistBasicCon,
 				SelfSigned, UserState, VerifyFun)
     end;
 
-%% This extension SHOULD NOT be marked critical. Its value
-%% does not have to be further validated at this point.
-validate_extensions(OtpCert, [#'Extension'{extnID = ?'id-ce-issuerAltName',
-					   extnValue = _} | Rest],
-		    ValidationState, ExistBasicCon,
-		    SelfSigned, UserState, VerifyFun) ->
-    validate_extensions(OtpCert, Rest, ValidationState, ExistBasicCon,
-			SelfSigned, UserState, VerifyFun);
-
-%% This extension MUST NOT be marked critical.Its value
-%% does not have to be further validated at this point.
-validate_extensions(OtpCert, [#'Extension'{extnID = Id,
-					   extnValue = _,
-					   critical = false} | Rest],
-		    ValidationState, 
-		    ExistBasicCon, SelfSigned,
-		    UserState, VerifyFun)
-  when Id == ?'id-ce-subjectKeyIdentifier'; 
-       Id == ?'id-ce-authorityKeyIdentifier'->
-    validate_extensions(OtpCert, Rest, ValidationState, ExistBasicCon,
-			SelfSigned, UserState, VerifyFun);
-
 validate_extensions(OtpCert, [#'Extension'{extnID = ?'id-ce-nameConstraints',
 				  extnValue = NameConst} | Rest], 
 		    ValidationState, 
@@ -592,7 +576,6 @@ validate_extensions(OtpCert, [#'Extension'{extnID = ?'id-ce-nameConstraints',
     validate_extensions(OtpCert, Rest, NewValidationState, ExistBasicCon,
 			SelfSigned, UserState, VerifyFun);
 
-
 validate_extensions(OtpCert, [#'Extension'{extnID = ?'id-ce-certificatePolicies',
 					   critical = true} = Ext| Rest], ValidationState,
 		    ExistBasicCon, SelfSigned, UserState0, VerifyFun) ->
@@ -653,13 +636,13 @@ is_valid_key_usage(KeyUse, Use) ->
     lists:member(Use, KeyUse).
  
 validate_subject_alt_names([]) ->
-    true;
+    false;
 validate_subject_alt_names([AltName | Rest]) ->
     case is_valid_subject_alt_name(AltName) of
 	true ->
-	    validate_subject_alt_names(Rest);
+	    true;
 	false ->
-	    false
+	    validate_subject_alt_names(Rest)
     end.
 
 is_valid_subject_alt_name({Name, Value}) when Name == rfc822Name;
@@ -688,7 +671,7 @@ is_valid_subject_alt_name({directoryName, _}) ->
 is_valid_subject_alt_name({_, [_|_]}) ->
     true;
 is_valid_subject_alt_name({otherName, #'AnotherName'{}}) ->
-    other;
+    false;
 is_valid_subject_alt_name({_, _}) ->
     false.
 
diff --git a/lib/public_key/src/public_key.erl b/lib/public_key/src/public_key.erl
index 68bf04eeff..9c7817fa8e 100644
--- a/lib/public_key/src/public_key.erl
+++ b/lib/public_key/src/public_key.erl
@@ -539,6 +539,7 @@ validate(DerCert, #path_validation_state{working_issuer_name = Issuer,
 					 user_state = UserState0,
 					 verify_fun = VerifyFun} =
 	     ValidationState0) ->
+
     OtpCert = pkix_decode_cert(DerCert, otp),
 
     UserState1 = pubkey_cert:validate_time(OtpCert, UserState0, VerifyFun),
@@ -556,10 +557,12 @@ validate(DerCert, #path_validation_state{working_issuer_name = Issuer,
 
     %% We want the key_usage extension to be checked before we validate
     %% the signature. 
-    UserState = pubkey_cert:validate_signature(OtpCert, DerCert,
+    UserState0 = pubkey_cert:validate_signature(OtpCert, DerCert,
 						Key, KeyParams, UserState5, VerifyFun),
+    UserState = pubkey_cert:verify_fun(OtpCert, valid, UserState0, VerifyFun),
     ValidationState  = 
 	ValidationState1#path_validation_state{user_state = UserState},
+
     pubkey_cert:prepare_for_next_cert(OtpCert, ValidationState).
 
 sized_binary(Binary) when is_binary(Binary) ->