Commit 3d2d5b12 authored by Dana Keeler's avatar Dana Keeler Committed by Pier Angelo Vendrame
Browse files

Bug 2027310 - improve thread coordination in ShowProtectedAuthPrompt r=jschanck 

Differential Revision: https://phabricator.services.mozilla.com/D291021
parent 45870afc

security/manager/ssl/nsNSSCallbacks.cpp

+32 −8
Original line number Diff line number Diff line
@@ -491,6 +491,21 @@ mozilla::pkix::Result DoOCSPRequest( 
  return Success;

}



// Helper struct to simplify thread coordination in `ShowProtectedAuthPrompt`.

struct BackgroundPromptStatus final {

  explicit BackgroundPromptStatus(PK11SlotInfo* slot)

      : mSlot(slot), mDone(false), mResult(SECFailure) {}



  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(BackgroundPromptStatus)



  UniquePK11SlotInfo mSlot;

  Atomic<bool> mDone;

  SECStatus mResult;



 private:

  ~BackgroundPromptStatus() = default;

};



static char* ShowProtectedAuthPrompt(PK11SlotInfo* slot, nsIPrompt* prompt) {

  MOZ_ASSERT(NS_IsMainThread());

  MOZ_ASSERT(slot);
@@ -501,12 +516,13 @@ static char* ShowProtectedAuthPrompt(PK11SlotInfo* slot, nsIPrompt* prompt) { 


  // Dispatch a background task to (eventually) call C_Login. The call will

  // block until the protected authentication succeeds or fails.

  Atomic<bool> done;

  Atomic<SECStatus> result;

  nsresult rv =

      NS_DispatchBackgroundTask(NS_NewRunnableFunction(__func__, [&]() mutable {

        result = PK11_CheckUserPassword(slot, nullptr);

        done = true;

  RefPtr<BackgroundPromptStatus> backgroundPromptStatus(

      new BackgroundPromptStatus(PK11_ReferenceSlot(slot)));

  nsresult rv = NS_DispatchBackgroundTask(

      NS_NewRunnableFunction(__func__, [backgroundPromptStatus]() mutable {

        backgroundPromptStatus->mResult = PK11_CheckUserPassword(

            backgroundPromptStatus->mSlot.get(), nullptr);

        backgroundPromptStatus->mDone = true;

      }));

  if (NS_FAILED(rv)) {

    return nullptr;
@@ -529,15 +545,23 @@ static char* ShowProtectedAuthPrompt(PK11SlotInfo* slot, nsIPrompt* prompt) { 
  if (NS_FAILED(errorResult.StealNSResult())) {

    return nullptr;

  }



  // The idea here is to dispatch the background task before showing the

  // (synchronous) alert, so that the browser is telling the user what to do

  // while waiting for the protected authentication (if the alert were shown

  // before dispatching the task, the user would have to dismiss it first).

  rv = prompt->Alert(nullptr, NS_ConvertUTF8toUTF16(promptString).get());

  if (NS_FAILED(rv)) {

    return nullptr;

  }



  // Spin the event loop until the background task has completed.

  MOZ_ALWAYS_TRUE(SpinEventLoopUntil(

      "ShowProtectedAuthPrompt"_ns, [&]() { return static_cast<bool>(done); }));

      "ShowProtectedAuthPrompt"_ns, [backgroundPromptStatus]() {

        return static_cast<bool>(backgroundPromptStatus->mDone);

      }));



  switch (result) {

  switch (backgroundPromptStatus->mResult) {

    case SECSuccess:

      return ToNewCString(nsDependentCString(PK11_PW_AUTHENTICATED));

    case SECWouldBlock: