ffi: keep FFI functions non-constructible

Use concise method functions for Fast API and shared-buffer wrappers,
and create native fallback functions with ConstructorBehavior::kThrow,
so FFI functions remain non-constructible on all invocation paths.
Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com>
Assisted-by: codex:gpt-5.6-sol
PR-URL: #65184Fixes: #65183
Reviewed-By: Paolo Insogna <paolo@cowtech.it>

Author: trivikr

lib/internal/ffi-shared-buffer.js

@@ -198,6 +198,8 @@ function inheritMetadata(wrapper, rawFn, nargs) {
 // arguments out of it into invocation-local storage before `ffi_call` and
 // reads the return value back only after, so nested/reentrant calls into
 // the same function are safe.
+// Concise methods do not have [[Construct]], unlike function expressions, so
+// use them below to match the native FFI functions' non-constructible behavior.
 functionwrapWithSharedBuffer(rawFn,signature){
 if(rawFn==null)returnrawFn;
 constbuffer=rawFn[kSbSharedBuffer];
@@ -254,7 +256,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 // so arity specialization wouldn't buy much here.
 assert(slowInvoke!==undefined,
 'FFI: shared-buffer raw function with pointer arguments is missing kSbInvokeSlow');
-wrapper=function(...args){
+wrapper={invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -271,7 +273,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 }
 rawFn();
 returnretGetter===null ? undefined : retGetter(view,0,true);
-};
+}}.invoke;
 }else{
 // Arity specialization avoids the per-call `Array` allocation of
 // `...args`; the void/non-void split removes a per-call branch on
@@ -295,67 +297,67 @@ function buildNumericWrapper(
 /* c8 ignore start */
 if(nargs===0){
 if(retGetter===null){
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 /* c8 ignore stop */
 if(nargs===1){
 consti0=argInfos[0];
 consto0=argOffsets[0];
 if(retGetter===null){
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===2){
 consti0=argInfos[0];
 consti1=argInfos[1];
 consto0=argOffsets[0];
 consto1=argOffsets[1];
 if(retGetter===null){
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===3){
 consti0=argInfos[0];
@@ -365,17 +367,17 @@ function buildNumericWrapper(
 consto1=argOffsets[1];
 consto2=argOffsets[2];
 if(retGetter===null){
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
@@ -384,7 +386,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===4){
 consti0=argInfos[0];
@@ -396,7 +398,7 @@ function buildNumericWrapper(
 consto2=argOffsets[2];
 consto3=argOffsets[3];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -405,9 +407,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -417,7 +419,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===5){
 consti0=argInfos[0];
@@ -431,7 +433,7 @@ function buildNumericWrapper(
 consto3=argOffsets[3];
 consto4=argOffsets[4];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -441,9 +443,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -454,7 +456,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===6){
 consti0=argInfos[0];
@@ -470,7 +472,7 @@ function buildNumericWrapper(
 consto4=argOffsets[4];
 consto5=argOffsets[5];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -481,9 +483,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -495,22 +497,22 @@ function buildNumericWrapper(
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 // 7+ args: further specialization is diminishing returns and bloats
 // this builder.
 if(retGetter===null){
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
 for(leti=0;i<nargs;i++){
 writeNumericArg(view,argInfos[i],argOffsets[i],args[i],i);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -519,7 +521,7 @@ function buildNumericWrapper(
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 
 module.exports={

lib/internal/ffi/fast-api.js

@@ -254,6 +254,8 @@ function throwIfFastLibraryClosed(state) {
 }
 }
 
+// Concise methods do not have [[Construct]], unlike function expressions.
+// Keep wrappers non-constructible to match the native FFI functions.
 functionwrapWithRawPointerConversions(rawFn,argumentTypes,owner){
 if(rawFn===undefined||rawFn===null){
 returnrawFn;
@@ -287,7 +289,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 constmemory0=needsRawPointerConversion(t0)||string0;
 constfastBufferInvoke=needsPointerLikeConversion(t0) ?
 rawFn[kFastBufferInvoke] : undefined;
-wrapper=function(a0){
+wrapper={invoke(a0){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
@@ -312,13 +314,13 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 arg=getRawPointerArg(arg,0);
 }
 returnrawFn(arg);
-};
+}}.invoke;
 }elseif(nargs===2){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
-wrapper=function(a0,a1){
+wrapper={invoke(a0,a1){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
@@ -332,15 +334,15 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }elseif(nargs===3){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constc2=ArrayPrototypeIncludes(indexes,2);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
 constt2=argumentTypes[2];
-wrapper=function(a0,a1,a2){
+wrapper={invoke(a0,a1,a2){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
@@ -356,9 +358,9 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }else{
-wrapper=function(...args){
+wrapper={invoke(...args){
 throwIfFastLibraryClosed(state);
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
@@ -382,7 +384,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }
 
 returninheritMetadata(wrapper,rawFn,nargs);

src/node_ffi.cc

@@ -324,7 +324,9 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
  maybe_ret = Function::New(context,
  use_sb ? DynamicLibrary::InvokeFunctionSB
  : DynamicLibrary::InvokeFunction,
- info->object());
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow);
  }
 
  Local<Function> ret;
@@ -377,8 +379,11 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
 // (strings, Buffers, ArrayBuffers, and ArrayBufferViews).
 if (has_ptr_args) {
  Local<Function> slow_fn;
-if (!Function::New(
- context, DynamicLibrary::InvokeFunction, info->object())
+if (!Function::New(context,
+ DynamicLibrary::InvokeFunction,
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow)
  .ToLocal(&slow_fn)) {
 return MaybeLocal<Function>();
  }

test/ffi/test-ffi-dynamic-library.js

@@ -67,6 +67,27 @@ test('dlopen resolves functions from definitions', () => {
 }
 });
 
+test('FFI functions are not constructible',()=>{
+const{ lib, functions }=ffi.dlopen(libraryPath,{
+add_i32: fixtureSymbols.add_i32,
+multiply_f64: fixtureSymbols.multiply_f64,
+});
+
+try{
+assert.strictEqual(Object.hasOwn(functions.add_i32,'prototype'),false);
+assert.strictEqual(
+Object.hasOwn(functions.multiply_f64,'prototype'),false);
+assert.throws(
+()=>Reflect.construct(functions.add_i32,[20,22]),
+TypeError);
+assert.throws(
+()=>Reflect.construct(functions.multiply_f64,[6,7]),
+TypeError);
+}finally{
+lib.close();
+}
+});
+
 test('DynamicLibrary exposes functions and symbols',()=>{
 constlib=newffi.DynamicLibrary(libraryPath);
 

lib/internal/ffi-shared-buffer.js

@@ -198,6 +198,8 @@ function inheritMetadata(wrapper, rawFn, nargs) {
 // arguments out of it into invocation-local storage before `ffi_call` and
 // reads the return value back only after, so nested/reentrant calls into
 // the same function are safe.
+// Concise methods do not have [[Construct]], unlike function expressions, so
+// use them below to match the native FFI functions' non-constructible behavior.
 functionwrapWithSharedBuffer(rawFn,signature){
 if(rawFn==null)returnrawFn;
 constbuffer=rawFn[kSbSharedBuffer];
@@ -254,7 +256,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 // so arity specialization wouldn't buy much here.
 assert(slowInvoke!==undefined,
 'FFI: shared-buffer raw function with pointer arguments is missing kSbInvokeSlow');
-wrapper=function(...args){
+wrapper={invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -271,7 +273,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 }
 rawFn();
 returnretGetter===null ? undefined : retGetter(view,0,true);
-};
+}}.invoke;
 }else{
 // Arity specialization avoids the per-call `Array` allocation of
 // `...args`; the void/non-void split removes a per-call branch on
@@ -295,67 +297,67 @@ function buildNumericWrapper(
 /* c8 ignore start */
 if(nargs===0){
 if(retGetter===null){
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 /* c8 ignore stop */
 if(nargs===1){
 consti0=argInfos[0];
 consto0=argOffsets[0];
 if(retGetter===null){
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===2){
 consti0=argInfos[0];
 consti1=argInfos[1];
 consto0=argOffsets[0];
 consto1=argOffsets[1];
 if(retGetter===null){
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===3){
 consti0=argInfos[0];
@@ -365,17 +367,17 @@ function buildNumericWrapper(
 consto1=argOffsets[1];
 consto2=argOffsets[2];
 if(retGetter===null){
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
@@ -384,7 +386,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===4){
 consti0=argInfos[0];
@@ -396,7 +398,7 @@ function buildNumericWrapper(
 consto2=argOffsets[2];
 consto3=argOffsets[3];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -405,9 +407,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -417,7 +419,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===5){
 consti0=argInfos[0];
@@ -431,7 +433,7 @@ function buildNumericWrapper(
 consto3=argOffsets[3];
 consto4=argOffsets[4];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -441,9 +443,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -454,7 +456,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===6){
 consti0=argInfos[0];
@@ -470,7 +472,7 @@ function buildNumericWrapper(
 consto4=argOffsets[4];
 consto5=argOffsets[5];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -481,9 +483,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -495,22 +497,22 @@ function buildNumericWrapper(
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 // 7+ args: further specialization is diminishing returns and bloats
 // this builder.
 if(retGetter===null){
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
 for(leti=0;i<nargs;i++){
 writeNumericArg(view,argInfos[i],argOffsets[i],args[i],i);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -519,7 +521,7 @@ function buildNumericWrapper(
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 
 module.exports={

lib/internal/ffi/fast-api.js

@@ -254,6 +254,8 @@ function throwIfFastLibraryClosed(state) {
 }
 }
 
+// Concise methods do not have [[Construct]], unlike function expressions.
+// Keep wrappers non-constructible to match the native FFI functions.
 functionwrapWithRawPointerConversions(rawFn,argumentTypes,owner){
 if(rawFn===undefined||rawFn===null){
 returnrawFn;
@@ -287,7 +289,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 constmemory0=needsRawPointerConversion(t0)||string0;
 constfastBufferInvoke=needsPointerLikeConversion(t0) ?
 rawFn[kFastBufferInvoke] : undefined;
-wrapper=function(a0){
+wrapper={invoke(a0){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
@@ -312,13 +314,13 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 arg=getRawPointerArg(arg,0);
 }
 returnrawFn(arg);
-};
+}}.invoke;
 }elseif(nargs===2){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
-wrapper=function(a0,a1){
+wrapper={invoke(a0,a1){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
@@ -332,15 +334,15 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }elseif(nargs===3){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constc2=ArrayPrototypeIncludes(indexes,2);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
 constt2=argumentTypes[2];
-wrapper=function(a0,a1,a2){
+wrapper={invoke(a0,a1,a2){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
@@ -356,9 +358,9 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }else{
-wrapper=function(...args){
+wrapper={invoke(...args){
 throwIfFastLibraryClosed(state);
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
@@ -382,7 +384,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }
 
 returninheritMetadata(wrapper,rawFn,nargs);

src/node_ffi.cc

@@ -324,7 +324,9 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
  maybe_ret = Function::New(context,
  use_sb ? DynamicLibrary::InvokeFunctionSB
  : DynamicLibrary::InvokeFunction,
- info->object());
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow);
  }
 
  Local<Function> ret;
@@ -377,8 +379,11 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
 // (strings, Buffers, ArrayBuffers, and ArrayBufferViews).
 if (has_ptr_args) {
  Local<Function> slow_fn;
-if (!Function::New(
- context, DynamicLibrary::InvokeFunction, info->object())
+if (!Function::New(context,
+ DynamicLibrary::InvokeFunction,
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow)
  .ToLocal(&slow_fn)) {
 return MaybeLocal<Function>();
  }

test/ffi/test-ffi-dynamic-library.js

@@ -67,6 +67,27 @@ test('dlopen resolves functions from definitions', () => {
 }
 });
 
+test('FFI functions are not constructible',()=>{
+const{ lib, functions }=ffi.dlopen(libraryPath,{
+add_i32: fixtureSymbols.add_i32,
+multiply_f64: fixtureSymbols.multiply_f64,
+});
+
+try{
+assert.strictEqual(Object.hasOwn(functions.add_i32,'prototype'),false);
+assert.strictEqual(
+Object.hasOwn(functions.multiply_f64,'prototype'),false);
+assert.throws(
+()=>Reflect.construct(functions.add_i32,[20,22]),
+TypeError);
+assert.throws(
+()=>Reflect.construct(functions.multiply_f64,[6,7]),
+TypeError);
+}finally{
+lib.close();
+}
+});
+
 test('DynamicLibrary exposes functions and symbols',()=>{
 constlib=newffi.DynamicLibrary(libraryPath);
 

lib/internal/ffi-shared-buffer.js

@@ -198,6 +198,8 @@ function inheritMetadata(wrapper, rawFn, nargs) {
 // arguments out of it into invocation-local storage before `ffi_call` and
 // reads the return value back only after, so nested/reentrant calls into
 // the same function are safe.
+// Concise methods do not have [[Construct]], unlike function expressions, so
+// use them below to match the native FFI functions' non-constructible behavior.
 functionwrapWithSharedBuffer(rawFn,signature){
 if(rawFn==null)returnrawFn;
 constbuffer=rawFn[kSbSharedBuffer];
@@ -254,7 +256,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 // so arity specialization wouldn't buy much here.
 assert(slowInvoke!==undefined,
 'FFI: shared-buffer raw function with pointer arguments is missing kSbInvokeSlow');
-wrapper=function(...args){
+wrapper={invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -271,7 +273,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 }
 rawFn();
 returnretGetter===null ? undefined : retGetter(view,0,true);
-};
+}}.invoke;
 }else{
 // Arity specialization avoids the per-call `Array` allocation of
 // `...args`; the void/non-void split removes a per-call branch on
@@ -295,67 +297,67 @@ function buildNumericWrapper(
 /* c8 ignore start */
 if(nargs===0){
 if(retGetter===null){
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 /* c8 ignore stop */
 if(nargs===1){
 consti0=argInfos[0];
 consto0=argOffsets[0];
 if(retGetter===null){
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===2){
 consti0=argInfos[0];
 consti1=argInfos[1];
 consto0=argOffsets[0];
 consto1=argOffsets[1];
 if(retGetter===null){
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===3){
 consti0=argInfos[0];
@@ -365,17 +367,17 @@ function buildNumericWrapper(
 consto1=argOffsets[1];
 consto2=argOffsets[2];
 if(retGetter===null){
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
@@ -384,7 +386,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===4){
 consti0=argInfos[0];
@@ -396,7 +398,7 @@ function buildNumericWrapper(
 consto2=argOffsets[2];
 consto3=argOffsets[3];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -405,9 +407,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -417,7 +419,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===5){
 consti0=argInfos[0];
@@ -431,7 +433,7 @@ function buildNumericWrapper(
 consto3=argOffsets[3];
 consto4=argOffsets[4];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -441,9 +443,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -454,7 +456,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===6){
 consti0=argInfos[0];
@@ -470,7 +472,7 @@ function buildNumericWrapper(
 consto4=argOffsets[4];
 consto5=argOffsets[5];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -481,9 +483,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -495,22 +497,22 @@ function buildNumericWrapper(
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 // 7+ args: further specialization is diminishing returns and bloats
 // this builder.
 if(retGetter===null){
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
 for(leti=0;i<nargs;i++){
 writeNumericArg(view,argInfos[i],argOffsets[i],args[i],i);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -519,7 +521,7 @@ function buildNumericWrapper(
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 
 module.exports={

lib/internal/ffi/fast-api.js

@@ -254,6 +254,8 @@ function throwIfFastLibraryClosed(state) {
 }
 }
 
+// Concise methods do not have [[Construct]], unlike function expressions.
+// Keep wrappers non-constructible to match the native FFI functions.
 functionwrapWithRawPointerConversions(rawFn,argumentTypes,owner){
 if(rawFn===undefined||rawFn===null){
 returnrawFn;
@@ -287,7 +289,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 constmemory0=needsRawPointerConversion(t0)||string0;
 constfastBufferInvoke=needsPointerLikeConversion(t0) ?
 rawFn[kFastBufferInvoke] : undefined;
-wrapper=function(a0){
+wrapper={invoke(a0){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
@@ -312,13 +314,13 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 arg=getRawPointerArg(arg,0);
 }
 returnrawFn(arg);
-};
+}}.invoke;
 }elseif(nargs===2){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
-wrapper=function(a0,a1){
+wrapper={invoke(a0,a1){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
@@ -332,15 +334,15 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }elseif(nargs===3){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constc2=ArrayPrototypeIncludes(indexes,2);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
 constt2=argumentTypes[2];
-wrapper=function(a0,a1,a2){
+wrapper={invoke(a0,a1,a2){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
@@ -356,9 +358,9 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }else{
-wrapper=function(...args){
+wrapper={invoke(...args){
 throwIfFastLibraryClosed(state);
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
@@ -382,7 +384,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }
 
 returninheritMetadata(wrapper,rawFn,nargs);

src/node_ffi.cc

@@ -324,7 +324,9 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
  maybe_ret = Function::New(context,
  use_sb ? DynamicLibrary::InvokeFunctionSB
  : DynamicLibrary::InvokeFunction,
- info->object());
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow);
  }
 
  Local<Function> ret;
@@ -377,8 +379,11 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
 // (strings, Buffers, ArrayBuffers, and ArrayBufferViews).
 if (has_ptr_args) {
  Local<Function> slow_fn;
-if (!Function::New(
- context, DynamicLibrary::InvokeFunction, info->object())
+if (!Function::New(context,
+ DynamicLibrary::InvokeFunction,
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow)
  .ToLocal(&slow_fn)) {
 return MaybeLocal<Function>();
  }

test/ffi/test-ffi-dynamic-library.js

@@ -67,6 +67,27 @@ test('dlopen resolves functions from definitions', () => {
 }
 });
 
+test('FFI functions are not constructible',()=>{
+const{ lib, functions }=ffi.dlopen(libraryPath,{
+add_i32: fixtureSymbols.add_i32,
+multiply_f64: fixtureSymbols.multiply_f64,
+});
+
+try{
+assert.strictEqual(Object.hasOwn(functions.add_i32,'prototype'),false);
+assert.strictEqual(
+Object.hasOwn(functions.multiply_f64,'prototype'),false);
+assert.throws(
+()=>Reflect.construct(functions.add_i32,[20,22]),
+TypeError);
+assert.throws(
+()=>Reflect.construct(functions.multiply_f64,[6,7]),
+TypeError);
+}finally{
+lib.close();
+}
+});
+
 test('DynamicLibrary exposes functions and symbols',()=>{
 constlib=newffi.DynamicLibrary(libraryPath);
 

lib/internal/ffi-shared-buffer.js

@@ -198,6 +198,8 @@ function inheritMetadata(wrapper, rawFn, nargs) {
 // arguments out of it into invocation-local storage before `ffi_call` and
 // reads the return value back only after, so nested/reentrant calls into
 // the same function are safe.
+// Concise methods do not have [[Construct]], unlike function expressions, so
+// use them below to match the native FFI functions' non-constructible behavior.
 functionwrapWithSharedBuffer(rawFn,signature){
 if(rawFn==null)returnrawFn;
 constbuffer=rawFn[kSbSharedBuffer];
@@ -254,7 +256,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 // so arity specialization wouldn't buy much here.
 assert(slowInvoke!==undefined,
 'FFI: shared-buffer raw function with pointer arguments is missing kSbInvokeSlow');
-wrapper=function(...args){
+wrapper={invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -271,7 +273,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 }
 rawFn();
 returnretGetter===null ? undefined : retGetter(view,0,true);
-};
+}}.invoke;
 }else{
 // Arity specialization avoids the per-call `Array` allocation of
 // `...args`; the void/non-void split removes a per-call branch on
@@ -295,67 +297,67 @@ function buildNumericWrapper(
 /* c8 ignore start */
 if(nargs===0){
 if(retGetter===null){
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 /* c8 ignore stop */
 if(nargs===1){
 consti0=argInfos[0];
 consto0=argOffsets[0];
 if(retGetter===null){
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===2){
 consti0=argInfos[0];
 consti1=argInfos[1];
 consto0=argOffsets[0];
 consto1=argOffsets[1];
 if(retGetter===null){
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===3){
 consti0=argInfos[0];
@@ -365,17 +367,17 @@ function buildNumericWrapper(
 consto1=argOffsets[1];
 consto2=argOffsets[2];
 if(retGetter===null){
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
@@ -384,7 +386,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===4){
 consti0=argInfos[0];
@@ -396,7 +398,7 @@ function buildNumericWrapper(
 consto2=argOffsets[2];
 consto3=argOffsets[3];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -405,9 +407,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -417,7 +419,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===5){
 consti0=argInfos[0];
@@ -431,7 +433,7 @@ function buildNumericWrapper(
 consto3=argOffsets[3];
 consto4=argOffsets[4];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -441,9 +443,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -454,7 +456,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===6){
 consti0=argInfos[0];
@@ -470,7 +472,7 @@ function buildNumericWrapper(
 consto4=argOffsets[4];
 consto5=argOffsets[5];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -481,9 +483,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -495,22 +497,22 @@ function buildNumericWrapper(
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 // 7+ args: further specialization is diminishing returns and bloats
 // this builder.
 if(retGetter===null){
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
 for(leti=0;i<nargs;i++){
 writeNumericArg(view,argInfos[i],argOffsets[i],args[i],i);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -519,7 +521,7 @@ function buildNumericWrapper(
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 
 module.exports={

lib/internal/ffi/fast-api.js

@@ -254,6 +254,8 @@ function throwIfFastLibraryClosed(state) {
 }
 }
 
+// Concise methods do not have [[Construct]], unlike function expressions.
+// Keep wrappers non-constructible to match the native FFI functions.
 functionwrapWithRawPointerConversions(rawFn,argumentTypes,owner){
 if(rawFn===undefined||rawFn===null){
 returnrawFn;
@@ -287,7 +289,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 constmemory0=needsRawPointerConversion(t0)||string0;
 constfastBufferInvoke=needsPointerLikeConversion(t0) ?
 rawFn[kFastBufferInvoke] : undefined;
-wrapper=function(a0){
+wrapper={invoke(a0){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
@@ -312,13 +314,13 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 arg=getRawPointerArg(arg,0);
 }
 returnrawFn(arg);
-};
+}}.invoke;
 }elseif(nargs===2){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
-wrapper=function(a0,a1){
+wrapper={invoke(a0,a1){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
@@ -332,15 +334,15 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }elseif(nargs===3){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constc2=ArrayPrototypeIncludes(indexes,2);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
 constt2=argumentTypes[2];
-wrapper=function(a0,a1,a2){
+wrapper={invoke(a0,a1,a2){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
@@ -356,9 +358,9 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }else{
-wrapper=function(...args){
+wrapper={invoke(...args){
 throwIfFastLibraryClosed(state);
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
@@ -382,7 +384,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }
 
 returninheritMetadata(wrapper,rawFn,nargs);

src/node_ffi.cc

@@ -324,7 +324,9 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
  maybe_ret = Function::New(context,
  use_sb ? DynamicLibrary::InvokeFunctionSB
  : DynamicLibrary::InvokeFunction,
- info->object());
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow);
  }
 
  Local<Function> ret;
@@ -377,8 +379,11 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
 // (strings, Buffers, ArrayBuffers, and ArrayBufferViews).
 if (has_ptr_args) {
  Local<Function> slow_fn;
-if (!Function::New(
- context, DynamicLibrary::InvokeFunction, info->object())
+if (!Function::New(context,
+ DynamicLibrary::InvokeFunction,
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow)
  .ToLocal(&slow_fn)) {
 return MaybeLocal<Function>();
  }

test/ffi/test-ffi-dynamic-library.js

@@ -67,6 +67,27 @@ test('dlopen resolves functions from definitions', () => {
 }
 });
 
+test('FFI functions are not constructible',()=>{
+const{ lib, functions }=ffi.dlopen(libraryPath,{
+add_i32: fixtureSymbols.add_i32,
+multiply_f64: fixtureSymbols.multiply_f64,
+});
+
+try{
+assert.strictEqual(Object.hasOwn(functions.add_i32,'prototype'),false);
+assert.strictEqual(
+Object.hasOwn(functions.multiply_f64,'prototype'),false);
+assert.throws(
+()=>Reflect.construct(functions.add_i32,[20,22]),
+TypeError);
+assert.throws(
+()=>Reflect.construct(functions.multiply_f64,[6,7]),
+TypeError);
+}finally{
+lib.close();
+}
+});
+
 test('DynamicLibrary exposes functions and symbols',()=>{
 constlib=newffi.DynamicLibrary(libraryPath);
 

lib/internal/ffi-shared-buffer.js

@@ -198,6 +198,8 @@ function inheritMetadata(wrapper, rawFn, nargs) {
 // arguments out of it into invocation-local storage before `ffi_call` and
 // reads the return value back only after, so nested/reentrant calls into
 // the same function are safe.
+// Concise methods do not have [[Construct]], unlike function expressions, so
+// use them below to match the native FFI functions' non-constructible behavior.
 functionwrapWithSharedBuffer(rawFn,signature){
 if(rawFn==null)returnrawFn;
 constbuffer=rawFn[kSbSharedBuffer];
@@ -254,7 +256,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 // so arity specialization wouldn't buy much here.
 assert(slowInvoke!==undefined,
 'FFI: shared-buffer raw function with pointer arguments is missing kSbInvokeSlow');
-wrapper=function(...args){
+wrapper={invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -271,7 +273,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 }
 rawFn();
 returnretGetter===null ? undefined : retGetter(view,0,true);
-};
+}}.invoke;
 }else{
 // Arity specialization avoids the per-call `Array` allocation of
 // `...args`; the void/non-void split removes a per-call branch on
@@ -295,67 +297,67 @@ function buildNumericWrapper(
 /* c8 ignore start */
 if(nargs===0){
 if(retGetter===null){
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 /* c8 ignore stop */
 if(nargs===1){
 consti0=argInfos[0];
 consto0=argOffsets[0];
 if(retGetter===null){
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===2){
 consti0=argInfos[0];
 consti1=argInfos[1];
 consto0=argOffsets[0];
 consto1=argOffsets[1];
 if(retGetter===null){
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===3){
 consti0=argInfos[0];
@@ -365,17 +367,17 @@ function buildNumericWrapper(
 consto1=argOffsets[1];
 consto2=argOffsets[2];
 if(retGetter===null){
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
@@ -384,7 +386,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===4){
 consti0=argInfos[0];
@@ -396,7 +398,7 @@ function buildNumericWrapper(
 consto2=argOffsets[2];
 consto3=argOffsets[3];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -405,9 +407,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -417,7 +419,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===5){
 consti0=argInfos[0];
@@ -431,7 +433,7 @@ function buildNumericWrapper(
 consto3=argOffsets[3];
 consto4=argOffsets[4];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -441,9 +443,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -454,7 +456,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===6){
 consti0=argInfos[0];
@@ -470,7 +472,7 @@ function buildNumericWrapper(
 consto4=argOffsets[4];
 consto5=argOffsets[5];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -481,9 +483,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -495,22 +497,22 @@ function buildNumericWrapper(
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 // 7+ args: further specialization is diminishing returns and bloats
 // this builder.
 if(retGetter===null){
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
 for(leti=0;i<nargs;i++){
 writeNumericArg(view,argInfos[i],argOffsets[i],args[i],i);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -519,7 +521,7 @@ function buildNumericWrapper(
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 
 module.exports={

lib/internal/ffi/fast-api.js

@@ -254,6 +254,8 @@ function throwIfFastLibraryClosed(state) {
 }
 }
 
+// Concise methods do not have [[Construct]], unlike function expressions.
+// Keep wrappers non-constructible to match the native FFI functions.
 functionwrapWithRawPointerConversions(rawFn,argumentTypes,owner){
 if(rawFn===undefined||rawFn===null){
 returnrawFn;
@@ -287,7 +289,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 constmemory0=needsRawPointerConversion(t0)||string0;
 constfastBufferInvoke=needsPointerLikeConversion(t0) ?
 rawFn[kFastBufferInvoke] : undefined;
-wrapper=function(a0){
+wrapper={invoke(a0){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
@@ -312,13 +314,13 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 arg=getRawPointerArg(arg,0);
 }
 returnrawFn(arg);
-};
+}}.invoke;
 }elseif(nargs===2){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
-wrapper=function(a0,a1){
+wrapper={invoke(a0,a1){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
@@ -332,15 +334,15 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }elseif(nargs===3){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constc2=ArrayPrototypeIncludes(indexes,2);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
 constt2=argumentTypes[2];
-wrapper=function(a0,a1,a2){
+wrapper={invoke(a0,a1,a2){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
@@ -356,9 +358,9 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }else{
-wrapper=function(...args){
+wrapper={invoke(...args){
 throwIfFastLibraryClosed(state);
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
@@ -382,7 +384,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }
 
 returninheritMetadata(wrapper,rawFn,nargs);

src/node_ffi.cc

@@ -324,7 +324,9 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
  maybe_ret = Function::New(context,
  use_sb ? DynamicLibrary::InvokeFunctionSB
  : DynamicLibrary::InvokeFunction,
- info->object());
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow);
  }
 
  Local<Function> ret;
@@ -377,8 +379,11 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
 // (strings, Buffers, ArrayBuffers, and ArrayBufferViews).
 if (has_ptr_args) {
  Local<Function> slow_fn;
-if (!Function::New(
- context, DynamicLibrary::InvokeFunction, info->object())
+if (!Function::New(context,
+ DynamicLibrary::InvokeFunction,
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow)
  .ToLocal(&slow_fn)) {
 return MaybeLocal<Function>();
  }

test/ffi/test-ffi-dynamic-library.js

@@ -67,6 +67,27 @@ test('dlopen resolves functions from definitions', () => {
 }
 });
 
+test('FFI functions are not constructible',()=>{
+const{ lib, functions }=ffi.dlopen(libraryPath,{
+add_i32: fixtureSymbols.add_i32,
+multiply_f64: fixtureSymbols.multiply_f64,
+});
+
+try{
+assert.strictEqual(Object.hasOwn(functions.add_i32,'prototype'),false);
+assert.strictEqual(
+Object.hasOwn(functions.multiply_f64,'prototype'),false);
+assert.throws(
+()=>Reflect.construct(functions.add_i32,[20,22]),
+TypeError);
+assert.throws(
+()=>Reflect.construct(functions.multiply_f64,[6,7]),
+TypeError);
+}finally{
+lib.close();
+}
+});
+
 test('DynamicLibrary exposes functions and symbols',()=>{
 constlib=newffi.DynamicLibrary(libraryPath);
 

lib/internal/ffi-shared-buffer.js

@@ -198,6 +198,8 @@ function inheritMetadata(wrapper, rawFn, nargs) {
 // arguments out of it into invocation-local storage before `ffi_call` and
 // reads the return value back only after, so nested/reentrant calls into
 // the same function are safe.
+// Concise methods do not have [[Construct]], unlike function expressions, so
+// use them below to match the native FFI functions' non-constructible behavior.
 functionwrapWithSharedBuffer(rawFn,signature){
 if(rawFn==null)returnrawFn;
 constbuffer=rawFn[kSbSharedBuffer];
@@ -254,7 +256,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 // so arity specialization wouldn't buy much here.
 assert(slowInvoke!==undefined,
 'FFI: shared-buffer raw function with pointer arguments is missing kSbInvokeSlow');
-wrapper=function(...args){
+wrapper={invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -271,7 +273,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 }
 rawFn();
 returnretGetter===null ? undefined : retGetter(view,0,true);
-};
+}}.invoke;
 }else{
 // Arity specialization avoids the per-call `Array` allocation of
 // `...args`; the void/non-void split removes a per-call branch on
@@ -295,67 +297,67 @@ function buildNumericWrapper(
 /* c8 ignore start */
 if(nargs===0){
 if(retGetter===null){
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 /* c8 ignore stop */
 if(nargs===1){
 consti0=argInfos[0];
 consto0=argOffsets[0];
 if(retGetter===null){
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===2){
 consti0=argInfos[0];
 consti1=argInfos[1];
 consto0=argOffsets[0];
 consto1=argOffsets[1];
 if(retGetter===null){
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===3){
 consti0=argInfos[0];
@@ -365,17 +367,17 @@ function buildNumericWrapper(
 consto1=argOffsets[1];
 consto2=argOffsets[2];
 if(retGetter===null){
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
@@ -384,7 +386,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===4){
 consti0=argInfos[0];
@@ -396,7 +398,7 @@ function buildNumericWrapper(
 consto2=argOffsets[2];
 consto3=argOffsets[3];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -405,9 +407,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -417,7 +419,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===5){
 consti0=argInfos[0];
@@ -431,7 +433,7 @@ function buildNumericWrapper(
 consto3=argOffsets[3];
 consto4=argOffsets[4];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -441,9 +443,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -454,7 +456,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===6){
 consti0=argInfos[0];
@@ -470,7 +472,7 @@ function buildNumericWrapper(
 consto4=argOffsets[4];
 consto5=argOffsets[5];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -481,9 +483,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -495,22 +497,22 @@ function buildNumericWrapper(
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 // 7+ args: further specialization is diminishing returns and bloats
 // this builder.
 if(retGetter===null){
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
 for(leti=0;i<nargs;i++){
 writeNumericArg(view,argInfos[i],argOffsets[i],args[i],i);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -519,7 +521,7 @@ function buildNumericWrapper(
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 
 module.exports={

lib/internal/ffi/fast-api.js

@@ -254,6 +254,8 @@ function throwIfFastLibraryClosed(state) {
 }
 }
 
+// Concise methods do not have [[Construct]], unlike function expressions.
+// Keep wrappers non-constructible to match the native FFI functions.
 functionwrapWithRawPointerConversions(rawFn,argumentTypes,owner){
 if(rawFn===undefined||rawFn===null){
 returnrawFn;
@@ -287,7 +289,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 constmemory0=needsRawPointerConversion(t0)||string0;
 constfastBufferInvoke=needsPointerLikeConversion(t0) ?
 rawFn[kFastBufferInvoke] : undefined;
-wrapper=function(a0){
+wrapper={invoke(a0){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
@@ -312,13 +314,13 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 arg=getRawPointerArg(arg,0);
 }
 returnrawFn(arg);
-};
+}}.invoke;
 }elseif(nargs===2){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
-wrapper=function(a0,a1){
+wrapper={invoke(a0,a1){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
@@ -332,15 +334,15 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }elseif(nargs===3){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constc2=ArrayPrototypeIncludes(indexes,2);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
 constt2=argumentTypes[2];
-wrapper=function(a0,a1,a2){
+wrapper={invoke(a0,a1,a2){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
@@ -356,9 +358,9 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }else{
-wrapper=function(...args){
+wrapper={invoke(...args){
 throwIfFastLibraryClosed(state);
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
@@ -382,7 +384,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }
 
 returninheritMetadata(wrapper,rawFn,nargs);

src/node_ffi.cc

@@ -324,7 +324,9 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
  maybe_ret = Function::New(context,
  use_sb ? DynamicLibrary::InvokeFunctionSB
  : DynamicLibrary::InvokeFunction,
- info->object());
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow);
  }
 
  Local<Function> ret;
@@ -377,8 +379,11 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
 // (strings, Buffers, ArrayBuffers, and ArrayBufferViews).
 if (has_ptr_args) {
  Local<Function> slow_fn;
-if (!Function::New(
- context, DynamicLibrary::InvokeFunction, info->object())
+if (!Function::New(context,
+ DynamicLibrary::InvokeFunction,
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow)
  .ToLocal(&slow_fn)) {
 return MaybeLocal<Function>();
  }

test/ffi/test-ffi-dynamic-library.js

@@ -67,6 +67,27 @@ test('dlopen resolves functions from definitions', () => {
 }
 });
 
+test('FFI functions are not constructible',()=>{
+const{ lib, functions }=ffi.dlopen(libraryPath,{
+add_i32: fixtureSymbols.add_i32,
+multiply_f64: fixtureSymbols.multiply_f64,
+});
+
+try{
+assert.strictEqual(Object.hasOwn(functions.add_i32,'prototype'),false);
+assert.strictEqual(
+Object.hasOwn(functions.multiply_f64,'prototype'),false);
+assert.throws(
+()=>Reflect.construct(functions.add_i32,[20,22]),
+TypeError);
+assert.throws(
+()=>Reflect.construct(functions.multiply_f64,[6,7]),
+TypeError);
+}finally{
+lib.close();
+}
+});
+
 test('DynamicLibrary exposes functions and symbols',()=>{
 constlib=newffi.DynamicLibrary(libraryPath);
 

lib/internal/ffi-shared-buffer.js

@@ -198,6 +198,8 @@ function inheritMetadata(wrapper, rawFn, nargs) {
 // arguments out of it into invocation-local storage before `ffi_call` and
 // reads the return value back only after, so nested/reentrant calls into
 // the same function are safe.
+// Concise methods do not have [[Construct]], unlike function expressions, so
+// use them below to match the native FFI functions' non-constructible behavior.
 functionwrapWithSharedBuffer(rawFn,signature){
 if(rawFn==null)returnrawFn;
 constbuffer=rawFn[kSbSharedBuffer];
@@ -254,7 +256,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 // so arity specialization wouldn't buy much here.
 assert(slowInvoke!==undefined,
 'FFI: shared-buffer raw function with pointer arguments is missing kSbInvokeSlow');
-wrapper=function(...args){
+wrapper={invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -271,7 +273,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 }
 rawFn();
 returnretGetter===null ? undefined : retGetter(view,0,true);
-};
+}}.invoke;
 }else{
 // Arity specialization avoids the per-call `Array` allocation of
 // `...args`; the void/non-void split removes a per-call branch on
@@ -295,67 +297,67 @@ function buildNumericWrapper(
 /* c8 ignore start */
 if(nargs===0){
 if(retGetter===null){
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 /* c8 ignore stop */
 if(nargs===1){
 consti0=argInfos[0];
 consto0=argOffsets[0];
 if(retGetter===null){
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===2){
 consti0=argInfos[0];
 consti1=argInfos[1];
 consto0=argOffsets[0];
 consto1=argOffsets[1];
 if(retGetter===null){
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===3){
 consti0=argInfos[0];
@@ -365,17 +367,17 @@ function buildNumericWrapper(
 consto1=argOffsets[1];
 consto2=argOffsets[2];
 if(retGetter===null){
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
@@ -384,7 +386,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===4){
 consti0=argInfos[0];
@@ -396,7 +398,7 @@ function buildNumericWrapper(
 consto2=argOffsets[2];
 consto3=argOffsets[3];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -405,9 +407,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -417,7 +419,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===5){
 consti0=argInfos[0];
@@ -431,7 +433,7 @@ function buildNumericWrapper(
 consto3=argOffsets[3];
 consto4=argOffsets[4];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -441,9 +443,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -454,7 +456,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===6){
 consti0=argInfos[0];
@@ -470,7 +472,7 @@ function buildNumericWrapper(
 consto4=argOffsets[4];
 consto5=argOffsets[5];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -481,9 +483,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -495,22 +497,22 @@ function buildNumericWrapper(
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 // 7+ args: further specialization is diminishing returns and bloats
 // this builder.
 if(retGetter===null){
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
 for(leti=0;i<nargs;i++){
 writeNumericArg(view,argInfos[i],argOffsets[i],args[i],i);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -519,7 +521,7 @@ function buildNumericWrapper(
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 
 module.exports={

lib/internal/ffi/fast-api.js

@@ -254,6 +254,8 @@ function throwIfFastLibraryClosed(state) {
 }
 }
 
+// Concise methods do not have [[Construct]], unlike function expressions.
+// Keep wrappers non-constructible to match the native FFI functions.
 functionwrapWithRawPointerConversions(rawFn,argumentTypes,owner){
 if(rawFn===undefined||rawFn===null){
 returnrawFn;
@@ -287,7 +289,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 constmemory0=needsRawPointerConversion(t0)||string0;
 constfastBufferInvoke=needsPointerLikeConversion(t0) ?
 rawFn[kFastBufferInvoke] : undefined;
-wrapper=function(a0){
+wrapper={invoke(a0){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
@@ -312,13 +314,13 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 arg=getRawPointerArg(arg,0);
 }
 returnrawFn(arg);
-};
+}}.invoke;
 }elseif(nargs===2){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
-wrapper=function(a0,a1){
+wrapper={invoke(a0,a1){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
@@ -332,15 +334,15 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }elseif(nargs===3){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constc2=ArrayPrototypeIncludes(indexes,2);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
 constt2=argumentTypes[2];
-wrapper=function(a0,a1,a2){
+wrapper={invoke(a0,a1,a2){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
@@ -356,9 +358,9 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }else{
-wrapper=function(...args){
+wrapper={invoke(...args){
 throwIfFastLibraryClosed(state);
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
@@ -382,7 +384,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }
 
 returninheritMetadata(wrapper,rawFn,nargs);

src/node_ffi.cc

@@ -324,7 +324,9 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
  maybe_ret = Function::New(context,
  use_sb ? DynamicLibrary::InvokeFunctionSB
  : DynamicLibrary::InvokeFunction,
- info->object());
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow);
  }
 
  Local<Function> ret;
@@ -377,8 +379,11 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
 // (strings, Buffers, ArrayBuffers, and ArrayBufferViews).
 if (has_ptr_args) {
  Local<Function> slow_fn;
-if (!Function::New(
- context, DynamicLibrary::InvokeFunction, info->object())
+if (!Function::New(context,
+ DynamicLibrary::InvokeFunction,
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow)
  .ToLocal(&slow_fn)) {
 return MaybeLocal<Function>();
  }

test/ffi/test-ffi-dynamic-library.js

@@ -67,6 +67,27 @@ test('dlopen resolves functions from definitions', () => {
 }
 });
 
+test('FFI functions are not constructible',()=>{
+const{ lib, functions }=ffi.dlopen(libraryPath,{
+add_i32: fixtureSymbols.add_i32,
+multiply_f64: fixtureSymbols.multiply_f64,
+});
+
+try{
+assert.strictEqual(Object.hasOwn(functions.add_i32,'prototype'),false);
+assert.strictEqual(
+Object.hasOwn(functions.multiply_f64,'prototype'),false);
+assert.throws(
+()=>Reflect.construct(functions.add_i32,[20,22]),
+TypeError);
+assert.throws(
+()=>Reflect.construct(functions.multiply_f64,[6,7]),
+TypeError);
+}finally{
+lib.close();
+}
+});
+
 test('DynamicLibrary exposes functions and symbols',()=>{
 constlib=newffi.DynamicLibrary(libraryPath);
 

lib/internal/ffi-shared-buffer.js

@@ -198,6 +198,8 @@ function inheritMetadata(wrapper, rawFn, nargs) {
 // arguments out of it into invocation-local storage before `ffi_call` and
 // reads the return value back only after, so nested/reentrant calls into
 // the same function are safe.
+// Concise methods do not have [[Construct]], unlike function expressions, so
+// use them below to match the native FFI functions' non-constructible behavior.
 functionwrapWithSharedBuffer(rawFn,signature){
 if(rawFn==null)returnrawFn;
 constbuffer=rawFn[kSbSharedBuffer];
@@ -254,7 +256,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 // so arity specialization wouldn't buy much here.
 assert(slowInvoke!==undefined,
 'FFI: shared-buffer raw function with pointer arguments is missing kSbInvokeSlow');
-wrapper=function(...args){
+wrapper={invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -271,7 +273,7 @@ function wrapWithSharedBuffer(rawFn, signature) {
 }
 rawFn();
 returnretGetter===null ? undefined : retGetter(view,0,true);
-};
+}}.invoke;
 }else{
 // Arity specialization avoids the per-call `Array` allocation of
 // `...args`; the void/non-void split removes a per-call branch on
@@ -295,67 +297,67 @@ function buildNumericWrapper(
 /* c8 ignore start */
 if(nargs===0){
 if(retGetter===null){
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(){
+return{invoke(){
 if(arguments.length!==0){
 throwFFIArgCountError(0,arguments.length);
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 /* c8 ignore stop */
 if(nargs===1){
 consti0=argInfos[0];
 consto0=argOffsets[0];
 if(retGetter===null){
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0){
+return{invoke(a0){
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===2){
 consti0=argInfos[0];
 consti1=argInfos[1];
 consto0=argOffsets[0];
 consto1=argOffsets[1];
 if(retGetter===null){
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1){
+return{invoke(a0,a1){
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===3){
 consti0=argInfos[0];
@@ -365,17 +367,17 @@ function buildNumericWrapper(
 consto1=argOffsets[1];
 consto2=argOffsets[2];
 if(retGetter===null){
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
 writeNumericArg(view,i0,o0,a0,0);
 writeNumericArg(view,i1,o1,a1,1);
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2){
+return{invoke(a0,a1,a2){
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
 }
@@ -384,7 +386,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===4){
 consti0=argInfos[0];
@@ -396,7 +398,7 @@ function buildNumericWrapper(
 consto2=argOffsets[2];
 consto3=argOffsets[3];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -405,9 +407,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i2,o2,a2,2);
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3){
+return{invoke(a0,a1,a2,a3){
 if(arguments.length!==4){
 throwFFIArgCountError(4,arguments.length);
 }
@@ -417,7 +419,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===5){
 consti0=argInfos[0];
@@ -431,7 +433,7 @@ function buildNumericWrapper(
 consto3=argOffsets[3];
 consto4=argOffsets[4];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -441,9 +443,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i3,o3,a3,3);
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4){
+return{invoke(a0,a1,a2,a3,a4){
 if(arguments.length!==5){
 throwFFIArgCountError(5,arguments.length);
 }
@@ -454,7 +456,7 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 if(nargs===6){
 consti0=argInfos[0];
@@ -470,7 +472,7 @@ function buildNumericWrapper(
 consto4=argOffsets[4];
 consto5=argOffsets[5];
 if(retGetter===null){
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -481,9 +483,9 @@ function buildNumericWrapper(
 writeNumericArg(view,i4,o4,a4,4);
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(a0,a1,a2,a3,a4,a5){
+return{invoke(a0,a1,a2,a3,a4,a5){
 if(arguments.length!==6){
 throwFFIArgCountError(6,arguments.length);
 }
@@ -495,22 +497,22 @@ function buildNumericWrapper(
 writeNumericArg(view,i5,o5,a5,5);
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 // 7+ args: further specialization is diminishing returns and bloats
 // this builder.
 if(retGetter===null){
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
 for(leti=0;i<nargs;i++){
 writeNumericArg(view,argInfos[i],argOffsets[i],args[i],i);
 }
 rawFn();
-};
+}}.invoke;
 }
-returnfunction(...args){
+return{invoke(...args){
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
 }
@@ -519,7 +521,7 @@ function buildNumericWrapper(
 }
 rawFn();
 returnretGetter(view,0,true);
-};
+}}.invoke;
 }
 
 module.exports={

lib/internal/ffi/fast-api.js

@@ -254,6 +254,8 @@ function throwIfFastLibraryClosed(state) {
 }
 }
 
+// Concise methods do not have [[Construct]], unlike function expressions.
+// Keep wrappers non-constructible to match the native FFI functions.
 functionwrapWithRawPointerConversions(rawFn,argumentTypes,owner){
 if(rawFn===undefined||rawFn===null){
 returnrawFn;
@@ -287,7 +289,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 constmemory0=needsRawPointerConversion(t0)||string0;
 constfastBufferInvoke=needsPointerLikeConversion(t0) ?
 rawFn[kFastBufferInvoke] : undefined;
-wrapper=function(a0){
+wrapper={invoke(a0){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==1){
 throwFFIArgCountError(1,arguments.length);
@@ -312,13 +314,13 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 arg=getRawPointerArg(arg,0);
 }
 returnrawFn(arg);
-};
+}}.invoke;
 }elseif(nargs===2){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
-wrapper=function(a0,a1){
+wrapper={invoke(a0,a1){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==2){
 throwFFIArgCountError(2,arguments.length);
@@ -332,15 +334,15 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }elseif(nargs===3){
 constc0=ArrayPrototypeIncludes(indexes,0);
 constc1=ArrayPrototypeIncludes(indexes,1);
 constc2=ArrayPrototypeIncludes(indexes,2);
 constt0=argumentTypes[0];
 constt1=argumentTypes[1];
 constt2=argumentTypes[2];
-wrapper=function(a0,a1,a2){
+wrapper={invoke(a0,a1,a2){
 throwIfFastLibraryClosed(state);
 if(arguments.length!==3){
 throwFFIArgCountError(3,arguments.length);
@@ -356,9 +358,9 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }else{
-wrapper=function(...args){
+wrapper={invoke(...args){
 throwIfFastLibraryClosed(state);
 if(args.length!==nargs){
 throwFFIArgCountError(nargs,args.length);
@@ -382,7 +384,7 @@ function wrapWithRawPointerConversions(rawFn, argumentTypes, owner) {
 }finally{
 if(stringCall)exitStringConversion(stringState);
 }
-};
+}}.invoke;
 }
 
 returninheritMetadata(wrapper,rawFn,nargs);

src/node_ffi.cc

@@ -324,7 +324,9 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
  maybe_ret = Function::New(context,
  use_sb ? DynamicLibrary::InvokeFunctionSB
  : DynamicLibrary::InvokeFunction,
- info->object());
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow);
  }
 
  Local<Function> ret;
@@ -377,8 +379,11 @@ MaybeLocal<Function> DynamicLibrary::CreateFunction(
 // (strings, Buffers, ArrayBuffers, and ArrayBufferViews).
 if (has_ptr_args) {
  Local<Function> slow_fn;
-if (!Function::New(
- context, DynamicLibrary::InvokeFunction, info->object())
+if (!Function::New(context,
+ DynamicLibrary::InvokeFunction,
+ info->object(),
+0,
+ v8::ConstructorBehavior::kThrow)
  .ToLocal(&slow_fn)) {
 return MaybeLocal<Function>();
  }

test/ffi/test-ffi-dynamic-library.js

@@ -67,6 +67,27 @@ test('dlopen resolves functions from definitions', () => {
 }
 });
 
+test('FFI functions are not constructible',()=>{
+const{ lib, functions }=ffi.dlopen(libraryPath,{
+add_i32: fixtureSymbols.add_i32,
+multiply_f64: fixtureSymbols.multiply_f64,
+});
+
+try{
+assert.strictEqual(Object.hasOwn(functions.add_i32,'prototype'),false);
+assert.strictEqual(
+Object.hasOwn(functions.multiply_f64,'prototype'),false);
+assert.throws(
+()=>Reflect.construct(functions.add_i32,[20,22]),
+TypeError);
+assert.throws(
+()=>Reflect.construct(functions.multiply_f64,[6,7]),
+TypeError);
+}finally{
+lib.close();
+}
+});
+
 test('DynamicLibrary exposes functions and symbols',()=>{
 constlib=newffi.DynamicLibrary(libraryPath);