GH-1461 Remove addition of invalid = character

AntelopeIO · Nov 13, 2023 · 00b2f99 · 00b2f99
1 parent 09e7fc2
commit 00b2f99
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Showing 2 changed files with 87 additions and 8 deletions.
diff --git a/libraries/libfc/src/variant.cpp b/libraries/libfc/src/variant.cpp
@@ -490,7 +490,7 @@ std::string variant::as_string()const
           return *reinterpret_cast<const bool*>(this) ? "true" : "false";
       case blob_type:
           if( get_blob().data.size() )
-             return base64_encode( get_blob().data.data(), get_blob().data.size() ) + "=";
+             return base64_encode( get_blob().data.data(), get_blob().data.size() );
           return std::string();
       case null_type:
           return std::string();
@@ -533,10 +533,14 @@ blob variant::as_blob()const
       {
          const std::string& str = get_string();
          if( str.size() == 0 ) return blob();
-         if( str.back() == '=' )
-         {
-            std::string b64 = base64_decode( get_string() );
-            return blob( { std::vector<char>( b64.begin(), b64.end() ) } );
+         try {
+            // pre-5.0 versions of variant added `=` to end of base64 encoded string in as_string() above.
+            // fc version of base64_decode allows for extra `=` at the end of the string.
+            // Other base64 decoders will not accept the extra `=`.
+            std::vector<char> b64 = base64_decode( str );
+            return blob( { std::move(b64) } );
+         } catch(const std::exception&) {
+            // unable to decode, return the raw chars
          }
          return blob( { std::vector<char>( str.begin(), str.end() ) } );
       }
@@ -758,8 +762,7 @@ void to_variant( const blob& b, variant& v ) {
 }
 
 void from_variant( const variant& v, blob& b ) {
-   std::string _s = base64_decode(v.as_string());
-   b.data = std::vector<char>(_s.begin(), _s.end());
+   b.data = base64_decode(v.as_string());
 }
 
 void to_variant( const UInt<8>& n, variant& v ) { v = uint64_t(n); }

diff --git a/libraries/libfc/test/variant/test_variant.cpp b/libraries/libfc/test/variant/test_variant.cpp
@@ -88,11 +88,87 @@ BOOST_AUTO_TEST_CASE(variant_format_string_limited)
       const string target_result = format_prefix + a_short_list + " " +
                                    "{" + "\"b\":\"" + b_short_list + "\",\"c\":\"" + c_short_list + "\"}" + " " +
                                    "[\"" + d_short_list + "\",\"" + e_short_list + "\"]" + " " +
-                                   base64_encode( a_blob.data.data(), a_blob.data.size() ) + "=" + " " +
+                                   base64_encode( a_blob.data.data(), a_blob.data.size() ) + " " +
                                    g_short_list;
 
       BOOST_CHECK_EQUAL( result, target_result);
       BOOST_CHECK_LT(result.size(), 1024 + 3 * mu.size());
    }
 }
+
+BOOST_AUTO_TEST_CASE(variant_blob)
+{
+   // Some test cases from https://github.com/ReneNyffenegger/cpp-base64
+   {
+      std::string a17_orig = "aaaaaaaaaaaaaaaaa";
+      std::string a17_encoded = "YWFhYWFhYWFhYWFhYWFhYWE=";
+      fc::mutable_variant_object mu;
+      mu("blob", blob{{a17_orig.begin(), a17_orig.end()}});
+      mu("str", a17_encoded);
+
+      BOOST_CHECK_EQUAL(mu["blob"].as_string(), a17_encoded);
+      std::vector<char> b64 = mu["str"].as_blob().data;
+      std::string_view b64_str(b64.data(), b64.size());
+      BOOST_CHECK_EQUAL(b64_str, a17_orig);
+   }
+   {
+      std::string s_6364 = "\x03" "\xef" "\xff" "\xf9";
+      std::string s_6364_encoded = "A+//+Q==";
+      fc::mutable_variant_object mu;
+      mu("blob", blob{{s_6364.begin(), s_6364.end()}});
+      mu("str", s_6364_encoded);
+
+      BOOST_CHECK_EQUAL(mu["blob"].as_string(), s_6364_encoded);
+      std::vector<char> b64 = mu["str"].as_blob().data;
+      std::string_view b64_str(b64.data(), b64.size());
+      BOOST_CHECK_EQUAL(b64_str, s_6364);
+   }
+   {
+      std::string org = "abc";
+      std::string encoded = "YWJj";
+
+      fc::mutable_variant_object mu;
+      mu("blob", blob{{org.begin(), org.end()}});
+      mu("str", encoded);
+
+      BOOST_CHECK_EQUAL(mu["blob"].as_string(), encoded);
+      std::vector<char> b64 = mu["str"].as_blob().data;
+      std::string_view b64_str(b64.data(), b64.size());
+      BOOST_CHECK_EQUAL(b64_str, org);
+   }
+}
+
+BOOST_AUTO_TEST_CASE(variant_blob_backwards_compatibility)
+{
+   // pre-5.0 variant would add an additional `=` as a flag that the blob data was base64 encoded
+   // verify variant can process encoded data with the extra `=`
+   {
+      std::string a17_orig = "aaaaaaaaaaaaaaaaa";
+      std::string a17_encoded = "YWFhYWFhYWFhYWFhYWFhYWE=";
+      std::string a17_encoded_old = a17_encoded + '=';
+      fc::mutable_variant_object mu;
+      mu("blob", blob{{a17_orig.begin(), a17_orig.end()}});
+      mu("str", a17_encoded_old);
+
+      BOOST_CHECK_EQUAL(mu["blob"].as_string(), a17_encoded);
+      std::vector<char> b64 = mu["str"].as_blob().data;
+      std::string_view b64_str(b64.data(), b64.size());
+      BOOST_CHECK_EQUAL(b64_str, a17_orig);
+   }
+   {
+      std::string org = "abc";
+      std::string encoded = "YWJj";
+      std::string encoded_old = encoded + '=';
+
+      fc::mutable_variant_object mu;
+      mu("blob", blob{{org.begin(), org.end()}});
+      mu("str", encoded_old);
+
+      BOOST_CHECK_EQUAL(mu["blob"].as_string(), encoded);
+      std::vector<char> b64 = mu["str"].as_blob().data;
+      std::string_view b64_str(b64.data(), b64.size());
+      BOOST_CHECK_EQUAL(b64_str, org);
+   }
+}
+
 BOOST_AUTO_TEST_SUITE_END()