From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Cheng Zhao <zcbenz@gmail.com>
Date: Thu, 4 Oct 2018 14:57:02 -0700
Subject: feat: support wasm-eval csp behind WebAssemblyCSP flag

This is a minimal backport of
https://chromium.googlesource.com/chromium/src/+/83913676803db53648b6a47d159102a7cf1dac36

The tracking issue in Chromium is
https://bugs.chromium.org/p/chromium/issues/detail?id=948834

diff --git a/third_party/blink/renderer/core/frame/csp/content_security_policy.cc b/third_party/blink/renderer/core/frame/csp/content_security_policy.cc
index 5e9aef4ef6398035c7a4704667d250d3fd54b25e..f8cf4b30c6ca02883b1c792bdb562c8550e8e17c 100644
--- a/third_party/blink/renderer/core/frame/csp/content_security_policy.cc
+++ b/third_party/blink/renderer/core/frame/csp/content_security_policy.cc
@@ -313,7 +313,8 @@ void ContentSecurityPolicy::CopyPluginTypesFrom(
 
 void ContentSecurityPolicy::DidReceiveHeaders(
     const ContentSecurityPolicyResponseHeaders& headers) {
-  if (headers.ShouldParseWasmEval())
+  if (RuntimeEnabledFeatures::WebAssemblyCSPEnabled() ||
+      headers.ShouldParseWasmEval())
     supports_wasm_eval_ = true;
   if (!headers.ContentSecurityPolicy().IsEmpty()) {
     AddAndReportPolicyFromHeaderValue(headers.ContentSecurityPolicy(),
diff --git a/third_party/blink/renderer/core/frame/csp/csp_directive_list.cc b/third_party/blink/renderer/core/frame/csp/csp_directive_list.cc
index 0411a75ca40371e1a309efba7b89e32f0edc917e..07b01fc682a172f5ed59c22285f9c968a9992307 100644
--- a/third_party/blink/renderer/core/frame/csp/csp_directive_list.cc
+++ b/third_party/blink/renderer/core/frame/csp/csp_directive_list.cc
@@ -314,9 +314,14 @@ bool CSPDirectiveList::CheckEval(
   return !directive || directive->allow_eval;
 }
 
+bool SupportsWasmEval(const ContentSecurityPolicy* policy) {
+  return RuntimeEnabledFeatures::WebAssemblyCSPEnabled() ||
+         policy->SupportsWasmEval();
+}
+
 bool CSPDirectiveList::CheckWasmEval(
     const network::mojom::blink::CSPSourceList* directive) const {
-  return !directive || directive->allow_wasm_eval;
+  return !directive || (SupportsWasmEval(policy_.Get()) && directive->allow_wasm_eval);
 }
 
 bool CSPDirectiveList::IsMatchingNoncePresent(
@@ -736,10 +741,14 @@ bool CSPDirectiveList::AllowWasmEval(
     ContentSecurityPolicy::ExceptionStatus exception_status,
     const String& content) const {
   if (reporting_disposition == ReportingDisposition::kReport) {
+    String infix = SupportsWasmEval(policy_.Get())
+                   ? "neither 'wasm-eval' nor 'unsafe-eval' is"
+                   : "'unsafe-eval' is not";
     return CheckWasmEvalAndReportViolation(
-        "Refused to compile or instantiate WebAssembly module because "
-        "'wasm-eval' is not an allowed source of script in the following "
-        "Content Security Policy directive: ",
+        "Refused to compile or instantiate WebAssembly module because " +
+            infix +
+            " an allowed source of script in the following "
+            "Content Security Policy directive: ",
         exception_status, content);
   }
   return IsReportOnly() ||
diff --git a/third_party/blink/renderer/core/frame/csp/source_list_directive.cc b/third_party/blink/renderer/core/frame/csp/source_list_directive.cc
index d28ab719440cde74e82d7d0f557987e50ef7f531..5b44cb7f0203e4cbe8898d1e25cd5c4c080ef5f6 100644
--- a/third_party/blink/renderer/core/frame/csp/source_list_directive.cc
+++ b/third_party/blink/renderer/core/frame/csp/source_list_directive.cc
@@ -403,10 +403,15 @@ bool ParseSource(const UChar* begin,
     return true;
   }
 
-  if (policy->SupportsWasmEval() &&
-      EqualIgnoringASCIICase("'wasm-eval'", token)) {
-    source_list.allow_wasm_eval = true;
-    return true;
+  // Temporarily behind a runtime feature
+  if (EqualIgnoringASCIICase("'wasm-eval'", token)) {
+    if (RuntimeEnabledFeatures::WebAssemblyCSPEnabled() ||
+        policy->SupportsWasmEval()) {
+      source_list.allow_wasm_eval = true;
+      return true;
+    } else {
+      return false;
+    }
   }
 
   if (EqualIgnoringASCIICase("'strict-dynamic'", token)) {
diff --git a/third_party/blink/renderer/platform/runtime_enabled_features.json5 b/third_party/blink/renderer/platform/runtime_enabled_features.json5
index c81216f07beb0fc363b0eb0d6b104031ca2c1992..2aba9f6528569c19461e0084f4a0495dfd6b59ea 100644
--- a/third_party/blink/renderer/platform/runtime_enabled_features.json5
+++ b/third_party/blink/renderer/platform/runtime_enabled_features.json5
@@ -2099,6 +2099,9 @@
     {
       name: "WebAppWindowControlsOverlay",
     },
+    {
+      name: "WebAssemblyCSP",
+    },
     {
       name: "WebAssemblySimd",
       origin_trial_feature_name: "WebAssemblySimd",