Ensure that CertStore::StoreCert never returns a cert_id of 0....

chrome/browser/cert_store.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/cert_store.h"
 
 #include <algorithm>
 #include <functional>
 
 #include "base/stl_util-inl.h"
@@ skipping 37 matching lines @@
 int CertStore::StoreCert(net::X509Certificate* cert, int process_id) {
   DCHECK(cert);
   AutoLock autoLock(cert_lock_);
 
   int cert_id;
 
   // Do we already know this cert?
   ReverseCertMap::iterator cert_iter = cert_to_id_.find(cert);
   if (cert_iter == cert_to_id_.end()) {
     cert_id = next_cert_id_++;
+    // We use 0 as an invalid cert_id value.  In the unlikely event that
+    // next_cert_id_ wraps around, we reset it to 1.
+    if (next_cert_id_ == 0)
+      next_cert_id_ = 1;
     cert->AddRef();
     id_to_cert_[cert_id] = cert;
     cert_to_id_[cert] = cert_id;
   } else {
     cert_id = cert_iter->second;
   }
 
   // Let's update process_id_to_cert_id_.
   if (std::find_if(process_id_to_cert_id_.lower_bound(process_id),
                    process_id_to_cert_id_.upper_bound(process_id),
@@ skipping 66 matching lines @@
 
 void CertStore::Observe(NotificationType type,
                         const NotificationSource& source,
                         const NotificationDetails& details) {
   DCHECK(type == NotificationType::RENDERER_PROCESS_TERMINATED ||
          type == NotificationType::RENDERER_PROCESS_CLOSED);
   RenderProcessHost* rph = Source<RenderProcessHost>(source).ptr();
   DCHECK(rph);
   RemoveCertsForRenderProcesHost(rph->id());
 }