Introduce timeout for retrieving system certificate database

This CL handles cases when TPM initialization fails and system token
certificate database was requested. It handles this case by introducing
a five-minutes-timeout for the database request.

Bug: 1068548, 844022
Change-Id: If738218f7816aa9af931fa23c85da39012b86b9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2410377Reviewed-by: Pavol Marko <pmarko@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Omar Morsi <omorsi@google.com>
Cr-Commit-Position: refs/heads/master@{#828853}

chrome/browser/chromeos/system_token_cert_db_initializer.cc

@@ -13,6 +13,7 @@
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/sequence_checker.h"
+#include "base/time/time.h"
 #include "build/branding_buildflags.h"
 #include "build/buildflag.h"
 #include "chrome/browser/chromeos/login/startup_utils.h"
@@ -29,6 +30,12 @@ namespace chromeos {
 
 namespace {
 
+// It is stated in cryptohome implementation that 5 minutes is enough time to
+// wait for any TPM operations. For more information, please refer to:
+// https://chromium.googlesource.com/chromiumos/platform2/+/master/cryptohome/cryptohome.cc
+constexpr base::TimeDelta kMaxCertDbRetrievalDelay =
+    base::TimeDelta::FromMinutes(5);
+
 // Called on UI Thread when the system slot has been retrieved.
 void GotSystemSlotOnUIThread(
     base::OnceCallback<void(crypto::ScopedPK11Slot)> callback_ui_thread,
@@ -141,8 +148,16 @@ void SystemTokenCertDBInitializer::GetSystemTokenCertDb(
 
   if (system_token_cert_database_) {
     std::move(callback).Run(system_token_cert_database_.get());
+  } else if (system_token_cert_db_retrieval_failed_) {
+    std::move(callback).Run(/*nss_cert_database=*/nullptr);
   } else {
     get_system_token_cert_db_callback_list_.AddUnsafe(std::move(callback));
+
+    if (!system_token_cert_db_retrieval_timer_.IsRunning()) {
+      system_token_cert_db_retrieval_timer_.Start(
+          FROM_HERE, kMaxCertDbRetrievalDelay, /*receiver=*/this,
+          &SystemTokenCertDBInitializer::OnSystemTokenDbRetrievalTimeout);
+    }
   }
 }
 
@@ -228,6 +243,7 @@ void SystemTokenCertDBInitializer::InitializeDatabase(
   database->SetSystemSlot(std::move(system_slot_copy));
 
   system_token_cert_database_ = std::move(database);
+  system_token_cert_db_retrieval_timer_.Stop();
   get_system_token_cert_db_callback_list_.Notify(
       system_token_cert_database_.get());
 
@@ -236,4 +252,12 @@ void SystemTokenCertDBInitializer::InitializeDatabase(
   NetworkCertLoader::Get()->SetSystemNSSDB(system_token_cert_database_.get());
 }
 
+void SystemTokenCertDBInitializer::OnSystemTokenDbRetrievalTimeout() {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
+  system_token_cert_db_retrieval_failed_ = true;
+  get_system_token_cert_db_callback_list_.Notify(
+      /*nss_cert_database=*/nullptr);
+}
+
 }  // namespace chromeos

chrome/browser/chromeos/system_token_cert_db_initializer.h

@@ -16,6 +16,7 @@
 #include "base/observer_list_types.h"
 #include "base/optional.h"
 #include "base/sequence_checker.h"
+#include "base/timer/timer.h"
 #include "chromeos/dbus/cryptohome/cryptohome_client.h"
 #include "crypto/scoped_nss_types.h"
 
@@ -66,7 +67,7 @@ class SystemTokenCertDBInitializer final : public CryptohomeClient::Observer {
   // To be notified when the returned NSSCertDatabase becomes invalid, callers
   // should register as SystemTokenCertDBObserver.
   using GetSystemTokenCertDbCallback =
-      base::OnceCallback<void(net::NSSCertDatabase*)>;
+      base::OnceCallback<void(net::NSSCertDatabase* nss_cert_database)>;
   void GetSystemTokenCertDb(GetSystemTokenCertDbCallback callback);
 
   // Adds |observer| as SystemTokenCertDBObserver.
@@ -91,6 +92,12 @@ class SystemTokenCertDBInitializer final : public CryptohomeClient::Observer {
   // Also starts NetworkCertLoader with the system token database.
   void InitializeDatabase(crypto::ScopedPK11Slot system_slot);
 
+  // Called after a delay if the system token certificate database was still not
+  // initialized when |GetSystemTokenCertDb| was called. This function notifies
+  // |get_system_token_cert_db_callback_list_| with nullptrs as a way of
+  // informing callers that the database initialization failed.
+  void OnSystemTokenDbRetrievalTimeout();
+
   // Whether the database initialization was started.
   bool started_initializing_ = false;
 
@@ -106,6 +113,10 @@ class SystemTokenCertDBInitializer final : public CryptohomeClient::Observer {
   // NSSCertDatabase is destroyed.
   base::ObserverList<SystemTokenCertDBObserver> observers_;
 
+  bool system_token_cert_db_retrieval_failed_ = false;
+
+  base::OneShotTimer system_token_cert_db_retrieval_timer_;
+
   SEQUENCE_CHECKER(sequence_checker_);
 
   base::WeakPtrFactory<SystemTokenCertDBInitializer> weak_ptr_factory_{this};