fix: tame Error constructor

endojs · Jun 27, 2020 · 0aa101d · 0aa101d
1 parent 198c780
commit 0aa101d
Showing 1 changed file with 87 additions and 0 deletions.
diff --git a/packages/ses/src/tame-global-error-object.js b/packages/ses/src/tame-global-error-object.js
@@ -10,6 +10,42 @@ export const NativeErrors = [
   URIError,
 ];
 
+// Whitelist names from https://v8.dev/docs/stack-trace-api
+// Whitelisting only the names used by error-stack-shim/src/v8StackFrames
+// callSiteToFrame to shim the error stack proposal.
+const safeV8CallSiteMethodNames = [
+  // suppress 'getThis' definitely
+  'getTypeName',
+  // suppress 'getFunction' definitely
+  'getFunctionName',
+  'getMethodName',
+  'getFileName',
+  'getLineNumber',
+  'getColumnNumber',
+  'getEvalOrigin',
+  // suppress 'isTopLevel' for now
+  'isEval',
+  // suppress 'isNative' for now
+  'isConstructor',
+  'isAsync',
+  // suppress 'isPromiseAll' for now
+  // suppress 'getPromiseIndex' for now
+
+  // Additional names found by experiment, absent from
+  // https://v8.dev/docs/stack-trace-api
+
+  // suppress 'getPosition' for now
+  // suppress 'getScriptNameOrSourceURL' for now
+  'toString', // TODO replace to use only whitelisted info
+];
+
+const safeV8CallSiteFacet = callSite => {
+  const methodEntry = name => [name, () => callSite[name]()];
+  return Object.fromEntries(safeV8CallSiteMethodNames.map(methodEntry));
+};
+
+const safeV8SST = sst => sst.map(safeV8CallSiteFacet);
+
 export default function tameGlobalErrorObject(errorTaming = 'safe') {
   if (errorTaming !== 'safe' && errorTaming !== 'unsafe') {
     throw new Error(`unrecognized errorTaming ${errorTaming}`);
@@ -38,6 +74,8 @@ export default function tameGlobalErrorObject(errorTaming = 'safe') {
   };
   */
 
+  let userPrepareStackTrace;
+
   // Use concise methods to obtain named functions without constructors.
   const tamedMethods = {
     captureStackTrace(error, optFn = undefined) {
@@ -51,6 +89,12 @@ export default function tameGlobalErrorObject(errorTaming = 'safe') {
       }
       Reflect.set(error, 'stack', '');
     },
+    prepareStackTrace(error, sst) {
+      if (typeof userPrepareStackTrace === 'function') {
+        return userPrepareStackTrace(error, safeV8SST(sst));
+      }
+      return [`${error}`, ...sst.map(callSite => `${callSite}`)].join('\n  ');
+    },
   };
 
   const ErrorPrototype = originalError.prototype;
@@ -97,6 +141,39 @@ export default function tameGlobalErrorObject(errorTaming = 'safe') {
       enumerable: false,
       configurable: true,
     },
+    prepareStackTrace: {
+      get() {
+        if (
+          errorTaming === 'unsafe' &&
+          typeof userPrepareStackTrace === 'function'
+        ) {
+          return tamedMethods.prepareStackTrace;
+        }
+        // By returning undefined, hopefully this means the VM will next consult
+        // originalError.prepareStackTrace, even on node despite
+        // https://bugs.chromium.org/p/v8/issues/detail?id=10551#c3
+        // or, if absent, fallback to the default behavior.
+        return undefined;
+      },
+      set(newPrepareStackTrace) {
+        if (errorTaming === 'unsafe') {
+          if (typeof newPrepareStackTrace === 'function') {
+            userPrepareStackTrace = newPrepareStackTrace;
+            originalError.prepareStackTrace = tamedMethods.prepareStackTrace;
+          } else {
+            userPrepareStackTrace = undefined;
+            delete originalError.prepareStackTrace;
+          }
+          // We place the useless return on the next line to ensure
+          // that anything we place after the if in the future only
+          // happens if the then-case does not.
+          // eslint-disable-next-line no-useless-return
+          return;
+        }
+      },
+      enumerable: false,
+      configurable: true,
+    },
   });
 
   // TODO uncomment. See TODO note above
@@ -120,6 +197,16 @@ export default function tameGlobalErrorObject(errorTaming = 'safe') {
       enumerable: false,
       configurable: true,
     },
+    prepareStackTrace: {
+      get() {
+        return undefined;
+      },
+      set(_) {
+        // ignore
+      },
+      enumerable: false,
+      configurable: true,
+    },
   });
   */