PER/UPER: Correct encoding for single-value extensible constraints

An extensible constraint which is a union of single values, such as:

  INTEGER (1|17, ...)

would be incorrectly encoded.

3 files changed, 88 insertions, 2 deletions

diff --git a/lib/asn1/src/asn1ct_imm.erl b/lib/asn1/src/asn1ct_imm.erl
index 892178f61b..7af7e192c3 100644
--- a/lib/asn1/src/asn1ct_imm.erl
+++ b/lib/asn1/src/asn1ct_imm.erl
@@ -994,6 +994,25 @@ mk_var(Base, V) ->
 
 per_enc_integer_1(Val, [], Aligned) ->
     [{'cond',[['_'|per_enc_unconstrained(Val, Aligned)]]}];
+per_enc_integer_1(Val, [{{'SingleValue',[_|_]=Svs}=Constr,[]}], Aligned) ->
+    %% An extensible constraint such as (1|17, ...).
+    %%
+    %% A subtle detail is that the extension root as described in the
+    %% ASN.1 spec should be used to determine whether a particular value
+    %% belongs to the extension root (as opposed to the effective
+    %% constraint, which will be used for the actual encoding).
+    %%
+    %% So for the example above, only the integers 1 and 17 should be
+    %% encoded as root values (extension bit = 0).
+
+    [{'ValueRange',{Lb,Ub}}] = effective_constraint(integer, [Constr]),
+    Root = [begin
+		{[],_,Put} = per_enc_constrained(Sv, Lb, Ub, Aligned),
+		[{eq,Val,Sv},{put_bits,0,1,[1]}|Put]
+	    end || Sv <- Svs],
+    Cs = Root ++ [['_',{put_bits,1,1,[1]}|
+		   per_enc_unconstrained(Val, Aligned)]],
+    build_cond(Cs);
 per_enc_integer_1(Val0, [{{_,_}=Constr,[]}], Aligned) ->
     {Prefix,Check,Action} = per_enc_integer_2(Val0, Constr, Aligned),
     Prefix++build_cond([[Check,{put_bits,0,1,[1]}|Action],
@@ -1004,7 +1023,7 @@ per_enc_integer_1(Val0, [Constr], Aligned) ->
     Prefix++build_cond([[Check|Action],
 			['_',{error,Val0}]]).
 
-per_enc_integer_2(Val, {'SingleValue',Sv}, Aligned) ->
+per_enc_integer_2(Val, {'SingleValue',Sv}, Aligned) when is_integer(Sv) ->
     per_enc_constrained(Val, Sv, Sv, Aligned);
 per_enc_integer_2(Val0, {'ValueRange',{Lb,'MAX'}}, Aligned)
   when is_integer(Lb) ->
diff --git a/lib/asn1/test/asn1_SUITE_data/Constraints.py b/lib/asn1/test/asn1_SUITE_data/Constraints.py
index e4bc987e4c..581ec2f467 100644
--- a/lib/asn1/test/asn1_SUITE_data/Constraints.py
+++ b/lib/asn1/test/asn1_SUITE_data/Constraints.py
@@ -17,6 +17,11 @@ NegSemiConstrained ::= INTEGER (-128..MAX)
 SemiConstrainedExt ::= INTEGER (42..MAX, ...)
 NegSemiConstrainedExt ::= INTEGER (-128..MAX, ...)
 
+-- Union of single values
+Sv1 ::= INTEGER (2|3|17)
+Sv2 ::= INTEGER (2|3|17, ...)
+Sv3 ::= INTEGER {a(2),b(3),z(17)} (2|3|17, ...)
+
 -- Other constraints
 FixedSize ::= OCTET STRING (SIZE(10)) 
 FixedSize2 ::= OCTET STRING (SIZE(10|20)) 
diff --git a/lib/asn1/test/testConstraints.erl b/lib/asn1/test/testConstraints.erl
index 9a1d62993d..34fbbcf6cc 100644
--- a/lib/asn1/test/testConstraints.erl
+++ b/lib/asn1/test/testConstraints.erl
@@ -122,6 +122,42 @@ int_constraints(Rules) ->
     range_error(Rules, 'X1', 21),
 
     %%==========================================================
+    %%  Union of single values
+    %%  Sv1 ::= INTEGER (2|3|17)
+    %%  Sv2 ::= INTEGER (2|3|17, ...)
+    %%  Sv3 ::= INTEGER {a(2),b(3),z(17)} (2|3|17, ...)
+    %%==========================================================
+
+    range_error(Rules, 'Sv1', 1),
+    range_error(Rules, 'Sv1', 18),
+    roundtrip('Sv1', 2),
+    roundtrip('Sv1', 3),
+    roundtrip('Sv1', 7),
+
+    %% Encoded as root
+    v_roundtrip(Rules, 'Sv2', 2),
+    v_roundtrip(Rules, 'Sv2', 3),
+    v_roundtrip(Rules, 'Sv2', 17),
+
+    %% Encoded as extension
+    v_roundtrip(Rules, 'Sv2', 1),
+    v_roundtrip(Rules, 'Sv2', 4),
+    v_roundtrip(Rules, 'Sv2', 18),
+
+    %% Encoded as root
+    v_roundtrip(Rules, 'Sv3', a),
+    v_roundtrip(Rules, 'Sv3', b),
+    v_roundtrip(Rules, 'Sv3', z),
+    v_roundtrip(Rules, 'Sv3', 2, a),
+    v_roundtrip(Rules, 'Sv3', 3, b),
+    v_roundtrip(Rules, 'Sv3', 17, z),
+
+    %% Encoded as extension
+    v_roundtrip(Rules, 'Sv3', 1),
+    v_roundtrip(Rules, 'Sv3', 4),
+    v_roundtrip(Rules, 'Sv3', 18),
+
+    %%==========================================================
     %%  SemiConstrained
     %%==========================================================
 
@@ -197,7 +233,29 @@ v(per, 'SemiConstrainedExt', 42+128) -> "000180";
 v(uper, 'SemiConstrainedExt', 42+128) -> "00C000";
 v(ber, 'NegSemiConstrainedExt', 0) -> "020100";
 v(per, 'NegSemiConstrainedExt', 0) -> "000180";
-v(uper, 'NegSemiConstrainedExt', 0) -> "00C000".
+v(uper, 'NegSemiConstrainedExt', 0) -> "00C000";
+v(ber, 'Sv2', 1) -> "020101";
+v(per, 'Sv2', 1) -> "800101";
+v(uper, 'Sv2', 1) -> "808080";
+v(ber, 'Sv2', 2) -> "020102";
+v(per, 'Sv2', 2) -> "00";
+v(uper, 'Sv2', 2) -> "00";
+v(ber, 'Sv2', 3) -> "020103";
+v(per, 'Sv2', 3) -> "08";
+v(uper, 'Sv2', 3) -> "08";
+v(ber, 'Sv2', 4) -> "020104";
+v(per, 'Sv2', 4) -> "800104";
+v(uper, 'Sv2', 4) -> "808200";
+v(ber, 'Sv2', 17) -> "020111";
+v(per, 'Sv2', 17) -> "78";
+v(uper, 'Sv2', 17) -> "78";
+v(ber, 'Sv2', 18) -> "020112";
+v(per, 'Sv2', 18) -> "800112";
+v(uper, 'Sv2', 18) -> "808900";
+v(Rule, 'Sv3', a) -> v(Rule, 'Sv2', 2);
+v(Rule, 'Sv3', b) -> v(Rule, 'Sv2', 3);
+v(Rule, 'Sv3', z) -> v(Rule, 'Sv2', 17);
+v(Rule, 'Sv3', Val) when is_integer(Val) -> v(Rule, 'Sv2', Val).
 
 shorter_ext(per, "a") -> <<16#80,16#01,16#61>>;
 shorter_ext(uper, "a") -> <<16#80,16#E1>>;
@@ -211,6 +269,10 @@ v_roundtrip(Erule, Type, Value) ->
     Encoded = asn1_test_lib:hex_to_bin(v(Erule, Type, Value)),
     Encoded = roundtrip('Constraints', Type, Value).
 
+v_roundtrip(Erule, Type, Value, Expected) ->
+    Encoded = asn1_test_lib:hex_to_bin(v(Erule, Type, Value)),
+    Encoded = asn1_test_lib:roundtrip_enc('Constraints', Type, Value, Expected).
+
 roundtrip(Type, Value) ->
     roundtrip('Constraints', Type, Value).