Reject reserved values and indefinite lengths

RFC 8949 defines additional information values 28, 29, 30 and 31 as
either reserved or indicating indefinite length values. Reject all of
these.

Test: cppbor_host_test_external
Change-Id: Ic9ae7630c8f75d060e4199d375c1f696699a4f66

2 files changed, 26 insertions, 1 deletions

diff --git a/src/cppbor_parse.cpp b/src/cppbor_parse.cpp
index 5cf76b2..fcf0dac 100644
--- a/src/cppbor_parse.cpp
+++ b/src/cppbor_parse.cpp
@@ -202,8 +202,13 @@ std::tuple<const uint8_t*, ParseClient*> parseRecursively(const uint8_t* begin,
 
     bool success = true;
     uint64_t addlData;
-    if (tagInt < ONE_BYTE_LENGTH || tagInt > EIGHT_BYTE_LENGTH) {
+    if (tagInt < ONE_BYTE_LENGTH) {
         addlData = tagInt;
+    } else if (tagInt > EIGHT_BYTE_LENGTH) {
+        parseClient->error(
+                begin,
+                "Reserved additional information value or unsupported indefinite length item.");
+        return {begin, nullptr};
     } else {
         switch (tagInt) {
             case ONE_BYTE_LENGTH:
diff --git a/tests/cppbor_test.cpp b/tests/cppbor_test.cpp
index 8a81e4e..ef98519 100644
--- a/tests/cppbor_test.cpp
+++ b/tests/cppbor_test.cpp
@@ -1714,6 +1714,26 @@ TEST(FullParserTest, ViewBstr) {
     EXPECT_THAT(item, MatchesItem(val));
 }
 
+TEST(FullParserTest, ReservedAdditionalInformation) {
+    vector<uint8_t> reservedVal = {0x1D};
+
+    auto [item, pos, message] = parse(reservedVal);
+    EXPECT_THAT(item, IsNull());
+    EXPECT_EQ(pos, reservedVal.data());
+    EXPECT_EQ("Reserved additional information value or unsupported indefinite length item.",
+              message);
+}
+
+TEST(FullParserTest, IndefiniteArray) {
+    vector<uint8_t> indefiniteArray = {0x7F};
+
+    auto [item, pos, message] = parse(indefiniteArray);
+    EXPECT_THAT(item, IsNull());
+    EXPECT_EQ(pos, indefiniteArray.data());
+    EXPECT_EQ("Reserved additional information value or unsupported indefinite length item.",
+              message);
+}
+
 TEST(MapGetValueByKeyTest, Map) {
     Array compoundItem(1, 2, 3, 4, 5, Map(4, 5, "a", "b"));
     auto clone = compoundItem.clone();