http: fix validation of "Link" header

SRHerzog · danielleadams · commit 9582c8ef3a37 · 2023-04-05T12:52:24.000-04:00
Updated regex for "Link" header validation to better match the specification in RFC 8288 section 3. Does not check for valid URI format but handles the rest of the header more permissively than before. Alternative to another outstanding PR that disables validation entirely. Fixes: #46453 Refs: https://www.rfc-editor.org/rfc/rfc8288.html#section-3 Refs: #46464 PR-URL: #46466 Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Paolo Insogna <paolo@cowtech.it> Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
diff --git a/lib/internal/validators.js b/lib/internal/validators.js
@@ -459,7 +459,15 @@ function validateUnion(value, name, union) {
   }
 }
 
-const linkValueRegExp = /^(?:<[^>]*>;)\s*(?:rel=(")?[^;"]*\1;?)\s*(?:(?:as|anchor|title|crossorigin|disabled|fetchpriority|rel|referrerpolicy)=(")?[^;"]*\2)?$/;
+/*
+  The rules for the Link header field are described here:
+  https://www.rfc-editor.org/rfc/rfc8288.html#section-3
+
+  This regex validates any string surrounded by angle brackets
+  (not necessarily a valid URI reference) followed by zero or more
+  link-params separated by semicolons.
+*/
+const linkValueRegExp = /^(?:<[^>]*>)(?:\s*;\s*[^;"\s]+(?:=(")?[^;"\s]*\1)?)*$/;
 
 /**
  * @param {any} value
diff --git a/test/parallel/test-http-early-hints-invalid-argument.js b/test/parallel/test-http-early-hints-invalid-argument.js
@@ -6,28 +6,44 @@ const debug = require('node:util').debuglog('test');
 
 const testResBody = 'response content\n';
 
-const server = http.createServer(common.mustCall((req, res) => {
-  debug('Server sending early hints...');
-  res.writeEarlyHints('bad argument type');
-
-  debug('Server sending full response...');
-  res.end(testResBody);
-}));
-
-server.listen(0, common.mustCall(() => {
-  const req = http.request({
-    port: server.address().port, path: '/'
-  });
-
-  req.end();
-  debug('Client sending request...');
-
-  req.on('information', common.mustNotCall());
-
-  process.on('uncaughtException', (err) => {
-    debug(`Caught an exception: ${JSON.stringify(err)}`);
-    if (err.name === 'AssertionError') throw err;
-    assert.strictEqual(err.code, 'ERR_INVALID_ARG_TYPE');
-    process.exit(0);
-  });
-}));
+{
+  const server = http.createServer(common.mustCall((req, res) => {
+    debug('Server sending early hints...');
+    assert.throws(() => {
+      res.writeEarlyHints('bad argument type');
+    }, (err) => err.code === 'ERR_INVALID_ARG_TYPE');
+
+    assert.throws(() => {
+      res.writeEarlyHints({
+        link: '</>; '
+      });
+    }, (err) => err.code === 'ERR_INVALID_ARG_VALUE');
+
+    assert.throws(() => {
+      res.writeEarlyHints({
+        link: 'rel=preload; </scripts.js>'
+      });
+    }, (err) => err.code === 'ERR_INVALID_ARG_VALUE');
+
+    assert.throws(() => {
+      res.writeEarlyHints({
+        link: 'invalid string'
+      });
+    }, (err) => err.code === 'ERR_INVALID_ARG_VALUE');
+
+    debug('Server sending full response...');
+    res.end(testResBody);
+    server.close();
+  }));
+
+  server.listen(0, common.mustCall(() => {
+    const req = http.request({
+      port: server.address().port, path: '/'
+    });
+
+    req.end();
+    debug('Client sending request...');
+
+    req.on('information', common.mustNotCall());
+  }));
+}
diff --git a/test/parallel/test-http-early-hints.js b/test/parallel/test-http-early-hints.js
@@ -58,7 +58,8 @@ const testResBody = 'response content\n';
     res.writeEarlyHints({
       link: [
         '</styles.css>; rel=preload; as=style',
-        '</scripts.js>; rel=preload; as=script',
+        '</scripts.js>; crossorigin; rel=preload; as=script',
+        '</scripts.js>; rel=preload; as=script; crossorigin',
       ]
     });
 
@@ -75,7 +76,8 @@ const testResBody = 'response content\n';
     req.on('information', common.mustCall((res) => {
       assert.strictEqual(
         res.headers.link,
-        '</styles.css>; rel=preload; as=style, </scripts.js>; rel=preload; as=script'
+        '</styles.css>; rel=preload; as=style, </scripts.js>; crossorigin; ' +
+        'rel=preload; as=script, </scripts.js>; rel=preload; as=script; crossorigin'
       );
     }));
 
