PER: Ensure that the complete encoding is at least one byte

If the encoding is empty (i.e. if a top-level type is single-valued
and therefore not encoding), the result should be a single zero
byte.

3 files changed, 17 insertions, 3 deletions

diff --git a/lib/asn1/src/asn1rtt_per.erl b/lib/asn1/src/asn1rtt_per.erl
index 84ff809912..aa6cf4da0a 100644
--- a/lib/asn1/src/asn1rtt_per.erl
+++ b/lib/asn1/src/asn1rtt_per.erl
@@ -963,7 +963,10 @@ encode_relative_oid(Val) when is_list(Val) ->
 %%
 
 complete(L) ->
-    asn1rt_nif:encode_per_complete(L).
+    case asn1rt_nif:encode_per_complete(L) of
+	<<>> -> <<0>>;
+	Bin -> Bin
+    end.
 
 octets_to_complete(Len,Val) when Len < 256 ->
     [20,Len,Val];
diff --git a/lib/asn1/src/asn1rtt_uper.erl b/lib/asn1/src/asn1rtt_uper.erl
index ad0678f3c3..8efe9a7b0f 100644
--- a/lib/asn1/src/asn1rtt_uper.erl
+++ b/lib/asn1/src/asn1rtt_uper.erl
@@ -1016,8 +1016,11 @@ complete(InList) when is_list(InList) ->
 		Bits -> <<Res/bitstring,0:(8-Bits)>>
 	end
     end;
-complete(InList) when is_binary(InList) ->
-    InList;
+complete(Bin) when is_binary(Bin) ->
+    case Bin of
+	<<>> -> <<0>>;
+	_ -> Bin
+    end;
 complete(InList) when is_bitstring(InList) ->
     PadLen = 8 - (bit_size(InList) band 7),
     <<InList/bitstring,0:PadLen>>.
diff --git a/lib/asn1/test/testPrim.erl b/lib/asn1/test/testPrim.erl
index 0d4427ba69..91fb9fffca 100644
--- a/lib/asn1/test/testPrim.erl
+++ b/lib/asn1/test/testPrim.erl
@@ -513,6 +513,14 @@ enum(Rules) ->
 		      case catch asn1_wrapper:encode('Prim','Enum',4) of Enum -> Enum end,
 		  ok
 	  end,
+
+    case Rules of
+	Per when Per =:= per; Per =:= uper ->
+	    {ok,<<0>>} = 'Prim':encode('SingleEnumVal', true),
+	    {ok,<<0>>} = 'Prim':encode('SingleEnumValExt', true);
+	ber ->
+	    ok
+    end,
     ok.