crypto: remove unused access of tlsext_hostname

The return value of loadSession is ultimately ignored, so don't fill it
in. This inches Node closer to 1.1.0 compatibility and is less code.

Also remove a comment which appears to have long since become invalid.
It dates to 048e0e7 when the SNI value
was actually extracted from the session.

This also fixes a segfault should d2i_SSL_SESSION fail to parse the
input and return NULL. Add a test for this case based on
test-tls-session-cache.js.

PR-URL: nodejs#10882
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

lib/_tls_wrap.js

@@ -66,12 +66,8 @@ function loadSession(self, hello, cb) {
     if (!self._handle)
       return cb(new Error('Socket is closed'));
 
-    // NOTE: That we have disabled OpenSSL's internal session storage in
-    // `node_crypto.cc` and hence its safe to rely on getting servername only
-    // from clienthello or this place.
-    var ret = self._handle.loadSession(session);
-
-    cb(null, ret);
+    self._handle.loadSession(session);
+    cb(null);
   }
 
   if (hello.sessionId.length <= 0 ||
@@ -148,7 +144,7 @@ function requestOCSP(self, hello, ctx, cb) {
 function onclienthello(hello) {
   var self = this;
 
-  loadSession(self, hello, function(err, session) {
+  loadSession(self, hello, function(err) {
     if (err)
       return self.destroy(err);
 

src/node_crypto.cc

@@ -1826,17 +1826,6 @@ void SSLWrap<Base>::LoadSession(const FunctionCallbackInfo<Value>& args) {
     if (w->next_sess_ != nullptr)
       SSL_SESSION_free(w->next_sess_);
     w->next_sess_ = sess;
-
-    Local<Object> info = Object::New(env->isolate());
-#ifndef OPENSSL_NO_TLSEXT
-    if (sess->tlsext_hostname == nullptr) {
-      info->Set(env->servername_string(), False(args.GetIsolate()));
-    } else {
-      info->Set(env->servername_string(),
-                OneByteString(args.GetIsolate(), sess->tlsext_hostname));
-    }
-#endif
-    args.GetReturnValue().Set(info);
   }
 }
 

test/parallel/test-tls-session-cache.js

@@ -13,7 +13,9 @@ if (!common.hasCrypto) {
 
 doTest({ tickets: false }, function() {
   doTest({ tickets: true }, function() {
-    console.error('all done');
+    doTest({ tickets: false, invalidSession: true }, function() {
+      console.error('all done');
+    });
   });
 });
 
@@ -23,6 +25,7 @@ function doTest(testOptions, callback) {
   const fs = require('fs');
   const join = require('path').join;
   const spawn = require('child_process').spawn;
+  const Buffer = require('buffer').Buffer;
 
   const keyFile = join(common.fixturesDir, 'agent.key');
   const certFile = join(common.fixturesDir, 'agent.crt');
@@ -36,6 +39,7 @@ function doTest(testOptions, callback) {
   };
   let requestCount = 0;
   let resumeCount = 0;
+  let newSessionCount = 0;
   let session;
 
   const server = tls.createServer(options, function(cleartext) {
@@ -50,6 +54,7 @@ function doTest(testOptions, callback) {
     cleartext.end();
   });
   server.on('newSession', function(id, data, cb) {
+    ++newSessionCount;
     // Emulate asynchronous store
     setTimeout(function() {
       assert.ok(!session);
@@ -65,9 +70,17 @@ function doTest(testOptions, callback) {
     assert.ok(session);
     assert.strictEqual(session.id.toString('hex'), id.toString('hex'));
 
+    let data = session.data;
+
+    // Return an invalid session to test Node does not crash.
+    if (testOptions.invalidSession) {
+      data = Buffer.from('INVALID SESSION');
+      session = null;
+    }
+
     // Just to check that async really works there
     setTimeout(function() {
-      callback(null, session.data);
+      callback(null, data);
     }, 100);
   });
 
@@ -118,14 +131,25 @@ function doTest(testOptions, callback) {
   });
 
   process.on('exit', function() {
+    // Each test run connects 6 times: an initial request and 5 reconnect
+    // requests.
+    assert.strictEqual(requestCount, 6);
+
     if (testOptions.tickets) {
-      assert.strictEqual(requestCount, 6);
+      // No session cache callbacks are called.
       assert.strictEqual(resumeCount, 0);
+      assert.strictEqual(newSessionCount, 0);
+    } else if (testOptions.invalidSession) {
+      // The resume callback was called, but each connection established a
+      // fresh session.
+      assert.strictEqual(resumeCount, 5);
+      assert.strictEqual(newSessionCount, 6);
     } else {
-      // initial request + reconnect requests (5 times)
+      // The resume callback was called, and only the initial connection
+      // establishes a fresh session.
       assert.ok(session);
-      assert.strictEqual(requestCount, 6);
       assert.strictEqual(resumeCount, 5);
+      assert.strictEqual(newSessionCount, 1);
     }
   });
 }