From 106dc8164fdb63b2fba27099eb4ff67fd48a686d Mon Sep 17 00:00:00 2001
From: legendecas <legendecas@gmail.com>
Date: Fri, 19 Aug 2022 21:42:39 +0800
Subject: [PATCH] src: restore context default
 IsCodeGenerationFromStringsAllowed value

Context's default IsCodeGenerationFromStringsAllowed value can be
changed by v8 flag `--disallow-code-generation-from-strings`. Restore
the value at runtime when delegating the code generation validation to
`node::ModifyCodeGenerationFromStrings`.

The context's settings are serialized in the snapshot. Reset the setting
values to its default values before the serialization so that it can be
correctly re-initialized after deserialization at runtime.
---
 src/api/environment.cc                              | 12 +++++++++---
 src/node_snapshotable.cc                            | 13 +++++++++++++
 ...st-eval-disallow-code-generation-from-strings.js |  9 +++++++++
 test/parallel/test-eval.js                          |  7 +++++++
 4 files changed, 38 insertions(+), 3 deletions(-)
 create mode 100644 test/parallel/test-eval-disallow-code-generation-from-strings.js
 create mode 100644 test/parallel/test-eval.js

diff --git a/src/api/environment.cc b/src/api/environment.cc
index a59f70e8139890..b1669c65a691d0 100644
--- a/src/api/environment.cc
+++ b/src/api/environment.cc
@@ -556,6 +556,15 @@ Maybe<bool> InitializeContextRuntime(Local<Context> context) {
   Isolate* isolate = context->GetIsolate();
   HandleScope handle_scope(isolate);
 
+  // Delegate the code generation validation to
+  // node::ModifyCodeGenerationFromStrings.
+  bool is_code_generation_from_strings_allowed =
+      context->IsCodeGenerationFromStringsAllowed();
+  context->AllowCodeGenerationFromStrings(false);
+  context->SetEmbedderData(
+      ContextEmbedderIndex::kAllowCodeGenerationFromStrings,
+      is_code_generation_from_strings_allowed ? True(isolate) : False(isolate));
+
   // Delete `Intl.v8BreakIterator`
   // https://github.com/nodejs/node/issues/14909
   {
@@ -665,9 +674,6 @@ Maybe<bool> InitializeContextForSnapshot(Local<Context> context) {
   Isolate* isolate = context->GetIsolate();
   HandleScope handle_scope(isolate);
 
-  context->AllowCodeGenerationFromStrings(false);
-  context->SetEmbedderData(
-      ContextEmbedderIndex::kAllowCodeGenerationFromStrings, True(isolate));
   context->SetEmbedderData(ContextEmbedderIndex::kAllowWasmCodeGeneration,
                            True(isolate));
 
diff --git a/src/node_snapshotable.cc b/src/node_snapshotable.cc
index 4399b7a3cc132d..dcfa47e7bcaa6b 100644
--- a/src/node_snapshotable.cc
+++ b/src/node_snapshotable.cc
@@ -956,6 +956,16 @@ const SnapshotData* SnapshotBuilder::GetEmbeddedSnapshotData() {
 )";
 }
 
+// Reset context settings that need to be initialized again after
+// deserialization.
+static void ResetContextSettingsBeforeSnapshot(Local<Context> context) {
+  // Reset the AllowCodeGenerationFromStrings flag to true (default value) so
+  // that it can be re-initialized with v8 flag
+  // --disallow-code-generation-from-strings and recognized in
+  // node::InitializeContextRuntime.
+  context->AllowCodeGenerationFromStrings(true);
+}
+
 Mutex SnapshotBuilder::snapshot_data_mutex_;
 
 const std::vector<intptr_t>& SnapshotBuilder::CollectExternalReferences() {
@@ -1108,6 +1118,9 @@ int SnapshotBuilder::Generate(SnapshotData* out,
 #endif
     }
 
+    ResetContextSettingsBeforeSnapshot(base_context);
+    ResetContextSettingsBeforeSnapshot(main_context);
+
     // Global handles to the contexts can't be disposed before the
     // blob is created. So initialize all the contexts before adding them.
     // TODO(joyeecheung): figure out how to remove this restriction.
diff --git a/test/parallel/test-eval-disallow-code-generation-from-strings.js b/test/parallel/test-eval-disallow-code-generation-from-strings.js
new file mode 100644
index 00000000000000..d701dbea299655
--- /dev/null
+++ b/test/parallel/test-eval-disallow-code-generation-from-strings.js
@@ -0,0 +1,9 @@
+// Flags: --disallow-code-generation-from-strings
+'use strict';
+
+require('../common');
+const assert = require('assert');
+
+// Verify that v8 option --disallow-code-generation-from-strings is still
+// respected
+assert.throws(() => eval(`'eval'`), EvalError);
diff --git a/test/parallel/test-eval.js b/test/parallel/test-eval.js
new file mode 100644
index 00000000000000..66eab0fa670199
--- /dev/null
+++ b/test/parallel/test-eval.js
@@ -0,0 +1,7 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+
+// Verify that eval is allowed by default.
+assert.strictEqual(eval(`'eval'`), 'eval');