Fix broken handling of default values for BIT STRINGs

For DER/PER/UPER, a value equal to the DEFAULT is not supposed to
be encoded.

BIT STRINGs values can be represented as Erlang terms in four
different ways: as an integer, as a list of zeroes and ones,
as a {Unused,Binary} tuple, or as an Erlang bitstring.

When encoding a BIT STRING, only certain representations of
BIT STRINGs values were recognized. All representations must
be recognized.

When decoding a DEFAULT value for a BIT STRING, the actual value
given in the decoding would be either an integer or a list
of zeroes and one (depending on how the literal was written in
the specification). We expect that the default value should be
in the same representation as any other BIT STRING value (i.e.
by default an Erlang bitstring, or a list if the 'legacy_bitstring'
option has been given, or as compact bitstring if 'compact_bitstring'
has been given).

1 files changed, 35 insertions, 70 deletions

diff --git a/lib/asn1/src/asn1ct_check.erl b/lib/asn1/src/asn1ct_check.erl
index eddcda0018..04227fd23b 100644
--- a/lib/asn1/src/asn1ct_check.erl
+++ b/lib/asn1/src/asn1ct_check.erl
@@ -2534,89 +2534,54 @@ normalize_integer(S,Int=#'Externalvaluereference'{value=Name},Type) ->
 normalize_integer(_,Int,_) ->
     exit({'Unknown INTEGER value',Int}).
 
-normalize_bitstring(S,Value,Type)->
-    %% There are four different Erlang formats of BIT STRING:
-    %% 1 - a list of ones and zeros.
-    %% 2 - a list of atoms.
-    %% 3 - as an integer, for instance in hexadecimal form.
-    %% 4 - as a tuple {Unused, Binary} where Unused is an integer
-    %%   and tells how many bits of Binary are unused.
-    %% 
-    %% normalize_bitstring/3 transforms Value according to:
-    %% A to 3,
-    %% B to 1,
-    %% C to 1 or 3
-    %% D to 2,
-    %% Value can be on format:
-    %% A - {hstring, String}, where String is a hexadecimal string.
-    %% B - {bstring, String}, where String is a string on bit format
-    %% C - #'Externalvaluereference'{value=V}, where V is a defined value
-    %% D - list of #'Externalvaluereference', where each value component
-    %%     is an identifier corresponing to NamedBits in Type.
-    %% E - list of ones and zeros, if Value already is normalized.
+%% normalize_bitstring(S, Value, Type) -> bitstring()
+%%  Convert a literal value for a BIT STRING to an Erlang bit string.
+%%
+normalize_bitstring(S, Value, Type)->
     case Value of
 	{hstring,String} when is_list(String) ->
-	    hstring_to_int(String);
+	    hstring_to_bitstring(String);
 	{bstring,String} when is_list(String) ->
-	    bstring_to_bitlist(String);
-	Rec when is_record(Rec,'Externalvaluereference') ->
-	    get_normalized_value(S,Value,Type,
-				 fun normalize_bitstring/3,[]);
+	    bstring_to_bitstring(String);
+	#'Externalvaluereference'{} ->
+	    get_normalized_value(S, Value, Type,
+				 fun normalize_bitstring/3, []);
 	RecList when is_list(RecList) ->
-	    case Type of
-		NBL when is_list(NBL) ->
-		    F = fun(#'Externalvaluereference'{value=Name}) ->
-				case lists:keysearch(Name,1,NBL) of
-				    {value,{Name,_}} ->
-					Name;
-				    Other ->
-					throw({error,Other})
-				end;
-			   (I) when I =:= 1; I =:= 0 ->
-				I;
-			   (Other) ->
-				throw({error,Other})
-			end,
-		    case catch lists:map(F,RecList) of
-			{error,Reason} ->
-			    asn1ct:warning("default value not "
-					   "compatible with type definition ~p~n",
-					   [Reason],S,
-					   "default value not "
-					   "compatible with type definition"),
-			    Value;
-			NewList ->
-			    NewList
-		    end;
-		_ ->
+	    F = fun(#'Externalvaluereference'{value=Name}) ->
+			case lists:keymember(Name, 1, Type) of
+			    true -> Name;
+			    false -> throw({error,false})
+			end;
+		   (Name) when is_atom(Name) ->
+			%% Already normalized.
+			Name;
+		   (Other) ->
+			throw({error,Other})
+		end,
+	    try
+		lists:map(F, RecList)
+	    catch
+		throw:{error,Reason} ->
 		    asn1ct:warning("default value not "
 				   "compatible with type definition ~p~n",
-				   [RecList],S,
+				   [Reason],S,
 				   "default value not "
 				   "compatible with type definition"),
 		    Value
 	    end;
-	{Name,String} when is_atom(Name) ->
-	    normalize_bitstring(S,String,Type);
-	Other ->
-	    asn1ct:warning("illegal default value ~p~n",[Other],S,
-			   "illegal default value"),
-	    Value
+	Bs when is_bitstring(Bs) ->
+	    %% Already normalized.
+	    Bs
     end.
 
-hstring_to_int(L) when is_list(L) ->
-    hstring_to_int(L,0).
-hstring_to_int([H|T],Acc) when H >= $A, H =< $F ->
-    hstring_to_int(T,(Acc bsl 4) + (H - $A + 10) ) ;
-hstring_to_int([H|T],Acc) when H >= $0, H =< $9 ->
-    hstring_to_int(T,(Acc bsl 4) + (H - $0));
-hstring_to_int([],Acc) ->
-    Acc.
+hstring_to_bitstring(L) ->
+    << <<(hex_to_int(D)):4>> || D <- L >>.
 
-bstring_to_bitlist([H|T]) when H == $0; H == $1 ->
-    [H - $0 | bstring_to_bitlist(T)];
-bstring_to_bitlist([]) ->
-    [].
+bstring_to_bitstring(L) ->
+    << <<(D-$0):1>> || D <- L >>.
+
+hex_to_int(D) when $0 =< D, D =< $9 -> D - $0;
+hex_to_int(D) when $A =< D, D =< $F -> D - ($A - 10).
 
 %% normalize_octetstring/1 changes representation of input Value to a 
 %% list of octets.