Merge branch 'develop' into Bronek/maximum_feature_name_size

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

include/xrpl/protocol/Feature.h

@@ -64,6 +64,24 @@
 
 namespace xrpl {
 
+// Feature names must not exceed this length (in characters, excluding the null terminator).
+static constexpr std::size_t maxFeatureNameSize = 63;
+// Reserve this exact feature-name length (in characters/bytes, excluding the null terminator)
+// so that a 32-byte uint256 (for example, in WASM or other interop contexts) can be used
+// as a compact, fixed-size feature selector without conflicting with human-readable names.
+static constexpr std::size_t reservedFeatureNameSize = 32;
+
+// Exposed for testing, used only by enforceValidFeatureNameSize in Feature.cpp
+template <std::size_t N>
+constexpr auto
+validFeatureNameSize(char const (*)[N]) -> bool
+{
+    // The -1 is to account for the null terminator in the string literal.
+    return N - 1 != reservedFeatureNameSize &&   //
+        N - 1 != reservedFeatureNameSize + 1 &&  //
+        N - 1 <= maxFeatureNameSize;
+}
+
 enum class VoteBehavior : int { Obsolete = -1, DefaultNo = 0, DefaultYes };
 enum class AmendmentSupport : int { Retired = -1, Supported = 0, Unsupported };
 

src/libxrpl/protocol/Feature.cpp

@@ -395,10 +395,20 @@ featureToName(uint256 const& f)
 #pragma push_macro("XRPL_RETIRE_FIX")
 #undef XRPL_RETIRE_FIX
 
+template <std::size_t N>
+constexpr auto
+enforceValidFeatureNameSize(char const (&n)[N]) -> char const*
+{
+    static_assert(validFeatureNameSize<N>(nullptr), "Invalid feature name size");
+    return n;
+}
+
 #define XRPL_FEATURE(name, supported, vote) \
-    uint256 const feature##name = registerFeature(#name, supported, vote);
+    uint256 const feature##name =           \
+        registerFeature(enforceValidFeatureNameSize(#name), supported, vote);
 #define XRPL_FIX(name, supported, vote) \
-    uint256 const fix##name = registerFeature("fix" #name, supported, vote);
+    uint256 const fix##name =           \
+        registerFeature(enforceValidFeatureNameSize("fix" #name), supported, vote);
 
 // clang-format off
 #define XRPL_RETIRE_FEATURE(name)                                       \

src/test/rpc/Feature_test.cpp

@@ -2,6 +2,7 @@
 
 #include <xrpl/ledger/AmendmentTable.h>
 #include <xrpl/protocol/Feature.h>
+#include <xrpl/protocol/digest.h>
 #include <xrpl/protocol/jss.h>
 
 namespace xrpl {
@@ -168,16 +169,18 @@ class Feature_test : public beast::unit_test::suite
         using namespace test::jtx;
         Env env{*this};
 
-        auto jrr = env.rpc("feature", "fixAMMOverflowOffer")[jss::result];
+        std::string const name = "fixAMMOverflowOffer";
+        auto jrr = env.rpc("feature", name)[jss::result];
         BEAST_EXPECTS(jrr[jss::status] == jss::success, "status");
         jrr.removeMember(jss::status);
         BEAST_EXPECT(jrr.size() == 1);
-        BEAST_EXPECT(jrr.isMember(
-            "12523DF04B553A0B1AD74F42DDB741DE8DC06A03FC089A0EF197E"
-            "2A87F1D8107"));
+        auto const expected = to_string(sha512Half(Slice(name.data(), name.size())));
+        char const sha[] = "12523DF04B553A0B1AD74F42DDB741DE8DC06A03FC089A0EF197E2A87F1D8107";
+        BEAST_EXPECT(expected == sha);
+        BEAST_EXPECT(jrr.isMember(expected));
         auto feature = *(jrr.begin());
 
-        BEAST_EXPECTS(feature[jss::name] == "fixAMMOverflowOffer", "name");
+        BEAST_EXPECTS(feature[jss::name] == name, "name");
         BEAST_EXPECTS(!feature[jss::enabled].asBool(), "enabled");
         BEAST_EXPECTS(feature[jss::vetoed].isBool() && !feature[jss::vetoed].asBool(), "vetoed");
         BEAST_EXPECTS(feature[jss::supported].asBool(), "supported");
@@ -186,6 +189,24 @@ class Feature_test : public beast::unit_test::suite
         jrr = env.rpc("feature", "fMM")[jss::result];
         BEAST_EXPECT(jrr[jss::error] == "badFeature");
         BEAST_EXPECT(jrr[jss::error_message] == "Feature unknown or invalid.");
+
+        // Test feature name size checks
+        char const ok63Name[] = "123456789012345678901234567890123456789012345678901234567890123";
+        static_assert(validFeatureNameSize(&ok63Name));
+
+        char const bad64Name[] = "1234567890123456789012345678901234567890123456789012345678901234";
+        static_assert(!validFeatureNameSize(&bad64Name));
+
+        char const ok31Name[] = "1234567890123456789012345678901";
+        static_assert(validFeatureNameSize(&ok31Name));
+
+        char const bad32Name[] = "12345678901234567890123456789012";
+        static_assert(!validFeatureNameSize(&bad32Name));
+        char const bad33Name[] = "123456789012345678901234567890123";
+        static_assert(!validFeatureNameSize(&bad33Name));
+
+        char const ok34Name[] = "1234567890123456789012345678901234";
+        static_assert(validFeatureNameSize(&ok34Name));
     }
 
     void