Addresses comments

Author: nikhil-gupta-tw

src/Cbor.cpp

@@ -5,6 +5,7 @@
 #include "Cbor.h"
 #include "HexCoding.h"
 #include "Numeric.h"
+#include "rust/bindgen/WalletCoreRSBindgen.h"
 
 #include <sstream>
 #include <cassert>
@@ -307,6 +308,9 @@ uint32_t Decode::getCompoundLength(uint32_t countMultiplier) const {
             break;
         }
         uint32_t elemLen = nextElem.getTotalLen();
+        if (elemLen == 0 || checkAddUnsignedOverflow(len, elemLen)) {
+            throw std::invalid_argument("CBOR invalid element length");
+        }
         if (len + elemLen > length()) {
             throw std::invalid_argument("CBOR array data too short");
         }
@@ -431,7 +435,13 @@ string Decode::dumpToStringInternal() const {
             break;
 
         case MT_string:
-            s << "\"" << getString() << "\"";
+            {
+                auto str = getString();
+                if (!Rust::tw_string_is_utf8_bytes(reinterpret_cast<const uint8_t*>(str.data()), str.size())) {
+                    throw std::invalid_argument("CBOR string is not valid UTF-8");
+                }
+                s << "\"" << str << "\"";
+            }
             break;
 
         case MT_array:

tests/common/CborTests.cpp

@@ -559,5 +559,21 @@ TEST(Cbor, BytesOverflowLength_getTotalLen) {
     FAIL() << "Expected exception";
 }
 
+TEST(Cbor, GetCompoundLengthOverflow) {
+    Data overflow = parse_hex("9bffffffffffffffff");
+    EXPECT_FALSE(Decode(overflow).isValid());
+}
+
+TEST(Cbor, StringInvalidUtf8Throws) {
+    Data invalidUtf8 = parse_hex("63fffefd");
+    Decode cbor(invalidUtf8);
+    EXPECT_THROW(cbor.dumpToString(), std::invalid_argument);
+}
+
+TEST(Cbor, StringValidUtf8) {
+    Data validUtf8 = Encode::string("hello").encoded();
+    EXPECT_EQ("\"hello\"", Decode(validUtf8).dumpToString());
+}
+
 // clang-format on
 } // namespace TW::Cbor::tests