[browser] refactor entropy

src/installer/pkg/sfx/Microsoft.NETCore.App/Directory.Build.props

@@ -217,7 +217,6 @@
     <PlatformManifestFileEntry Include="icudt_optimal_no_CJK.dat" IsNative="true" />
     <PlatformManifestFileEntry Include="icudt_hybrid.dat" IsNative="true" />
     <PlatformManifestFileEntry Include="package.json" IsNative="true" />
-    <PlatformManifestFileEntry Include="pal_random.lib.js" IsNative="true" />
     <PlatformManifestFileEntry Include="dotnet.es6.pre.js" IsNative="true" />
     <PlatformManifestFileEntry Include="dotnet.es6.lib.js" IsNative="true" />
     <PlatformManifestFileEntry Include="dotnet.es6.extpost.js" IsNative="true" />

src/mono/sample/wasm/browser-advanced/Program.cs

@@ -14,6 +14,9 @@ public static int Main(string[] args)
         {
             Console.WriteLine ("Hello, World!");
 
+            var rand = new Random();
+            Console.WriteLine ("Today's lucky number is " + rand.Next(100));
+
             var start = DateTime.UtcNow;
             var timezonesCount = TimeZoneInfo.GetSystemTimeZones().Count;
             var end = DateTime.UtcNow;

src/mono/wasm/runtime/CMakeLists.txt

@@ -34,8 +34,8 @@ target_link_libraries(dotnet.native
     ${NATIVE_BIN_DIR}/libSystem.IO.Compression.Native.a)
 
 set_target_properties(dotnet.native PROPERTIES
-    LINK_DEPENDS "${NATIVE_BIN_DIR}/src/emcc-default.rsp;${NATIVE_BIN_DIR}/src/es6/dotnet.es6.pre.js;${NATIVE_BIN_DIR}/src/es6/dotnet.es6.lib.js;${NATIVE_BIN_DIR}/src/pal_random.lib.js;${NATIVE_BIN_DIR}/src/es6/dotnet.es6.extpost.js;"
-    LINK_FLAGS "@${NATIVE_BIN_DIR}/src/emcc-default.rsp @${NATIVE_BIN_DIR}/src/emcc-link.rsp ${CONFIGURATION_LINK_FLAGS} --pre-js ${NATIVE_BIN_DIR}/src/es6/dotnet.es6.pre.js --js-library ${NATIVE_BIN_DIR}/src/es6/dotnet.es6.lib.js --js-library ${NATIVE_BIN_DIR}/src/pal_random.lib.js --extern-post-js ${NATIVE_BIN_DIR}/src/es6/dotnet.es6.extpost.js "
+    LINK_DEPENDS "${NATIVE_BIN_DIR}/src/emcc-default.rsp;${NATIVE_BIN_DIR}/src/es6/dotnet.es6.pre.js;${NATIVE_BIN_DIR}/src/es6/dotnet.es6.lib.js;${NATIVE_BIN_DIR}/src/es6/dotnet.es6.extpost.js;"
+    LINK_FLAGS "@${NATIVE_BIN_DIR}/src/emcc-default.rsp @${NATIVE_BIN_DIR}/src/emcc-link.rsp ${CONFIGURATION_LINK_FLAGS} --pre-js ${NATIVE_BIN_DIR}/src/es6/dotnet.es6.pre.js --js-library ${NATIVE_BIN_DIR}/src/es6/dotnet.es6.lib.js --extern-post-js ${NATIVE_BIN_DIR}/src/es6/dotnet.es6.extpost.js "
     RUNTIME_OUTPUT_DIRECTORY "${NATIVE_BIN_DIR}")
 
 set(ignoreMeWasmOptFlags "${CONFIGURATION_WASM_OPT_FLAGS}")

src/mono/wasm/runtime/crypto.ts

@@ -0,0 +1,27 @@
+import { isSharedArrayBuffer, localHeapViewU8 } from "./memory";
+
+// batchedQuotaMax is the max number of bytes as specified by the api spec.
+// If the byteLength of array is greater than 65536, throw a QuotaExceededError and terminate the algorithm.
+// https://www.w3.org/TR/WebCryptoAPI/#Crypto-method-getRandomValues
+const batchedQuotaMax = 65536;
+
+export function mono_wasm_browser_entropy(bufferPtr: number, bufferLength: number) {
+    const memoryView = localHeapViewU8();
+    const targetView = memoryView.subarray(bufferPtr, bufferPtr + bufferLength);
+
+    // When threading is enabled, Chrome doesn't want SharedArrayBuffer to be passed to crypto APIs
+    const needsCopy = isSharedArrayBuffer(memoryView.buffer);
+    const targetBuffer = needsCopy
+        ? new Uint8Array(bufferLength)
+        : targetView;
+
+    // fill the targetBuffer in batches of batchedQuotaMax
+    for (let i = 0; i < bufferLength; i += batchedQuotaMax) {
+        const targetBatch = new Uint8Array(targetBuffer, i, Math.min(bufferLength - i, batchedQuotaMax));
+        crypto.getRandomValues(targetBatch);
+    }
+
+    if (needsCopy) {
+        targetView.set(targetBuffer);
+    }
+}

src/mono/wasm/runtime/exports-binding.ts

@@ -35,6 +35,7 @@ import { mono_wasm_typed_array_to_array_ref } from "./net6-legacy/js-to-cs";
 import { mono_wasm_typed_array_from_ref } from "./net6-legacy/buffers";
 import { mono_wasm_get_culture_info } from "./hybrid-globalization/culture-info";
 import { mono_wasm_get_first_day_of_week, mono_wasm_get_first_week_of_year } from "./hybrid-globalization/locales";
+import { mono_wasm_browser_entropy } from "./crypto";
 
 // the JS methods would be visible to EMCC linker and become imports of the WASM module
 
@@ -98,6 +99,9 @@ export const mono_wasm_imports = [
     mono_wasm_set_entrypoint_breakpoint,
     mono_wasm_event_pipe_early_startup_callback,
 
+    // src/native/minipal/random.c
+    mono_wasm_browser_entropy,
+
     // corebindings.c
     mono_wasm_release_cs_owned_object,
     mono_wasm_bind_js_function,

src/mono/wasm/runtime/memory.ts

@@ -401,7 +401,10 @@ export function receiveWorkerHeapViews() {
 
 const sharedArrayBufferDefined = typeof SharedArrayBuffer !== "undefined";
 export function isSharedArrayBuffer(buffer: any): buffer is SharedArrayBuffer {
-    if (!MonoWasmThreads) return false;
     // this condition should be eliminated by rollup on non-threading builds
+    if (!MonoWasmThreads) return false;
+    // BEWARE: In some cases, `instanceof SharedArrayBuffer` returns false even though buffer is an SAB.
+    // Patch adapted from https://github.com/emscripten-core/emscripten/pull/16994
+    // See also https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toStringTag
     return sharedArrayBufferDefined && buffer[Symbol.toStringTag] === "SharedArrayBuffer";
 }

src/mono/wasm/runtime/strings.ts

@@ -242,9 +242,6 @@ function stringToMonoStringNewRoot(string: string, result: WasmRoot<MonoString>)
 // When threading is enabled, TextDecoder does not accept a view of a
 // SharedArrayBuffer, we must make a copy of the array first.
 // See https://github.com/whatwg/encoding/issues/172
-// BEWARE: In some cases, `instanceof SharedArrayBuffer` returns false even though buffer is an SAB.
-// Patch adapted from https://github.com/emscripten-core/emscripten/pull/16994
-// See also https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toStringTag
 export function viewOrCopy(view: Uint8Array, start: CharPtr, end: CharPtr): Uint8Array {
     // this condition should be eliminated by rollup on non-threading builds
     const needsCopy = isSharedArrayBuffer(view.buffer);

src/mono/wasm/wasm.proj

@@ -424,8 +424,7 @@
 
     <Copy SourceFiles="runtime/driver.c;
                        runtime/pinvoke.c;
-                       runtime/corebindings.c;
-                       $(SharedNativeRoot)libs\System.Native\pal_random.lib.js;"
+                       runtime/corebindings.c;"
           DestinationFolder="$(NativeBinDir)src"
           SkipUnchangedFiles="true" />
 

src/native/minipal/random.c

@@ -69,11 +69,11 @@ int32_t minipal_get_cryptographically_secure_random_bytes(uint8_t* buffer, int32
     assert(buffer != NULL);
 
 #ifdef __EMSCRIPTEN__
-    extern int32_t dotnet_browser_entropy(uint8_t* buffer, int32_t bufferLength);
+    extern int32_t mono_wasm_browser_entropy(uint8_t* buffer, int32_t bufferLength);
     static bool sMissingBrowserCrypto;
     if (!sMissingBrowserCrypto)
     {
-        int32_t bff = dotnet_browser_entropy(buffer, bufferLength);
+        int32_t bff = mono_wasm_browser_entropy(buffer, bufferLength);
         if (bff == -1)
             sMissingBrowserCrypto = true;
         else