Commit 3da36b47 authored by Jens Stutte's avatar Jens Stutte Committed by Pier Angelo Vendrame
Browse files

Bug 2016901 - Fix potential race in NSSIOLayer. r=keeler 

Differential Revision: https://phabricator.services.mozilla.com/D283409
parent 76ecd5e0

security/manager/ssl/nsNSSIOLayer.cpp

+19 −2
Original line number Diff line number Diff line
@@ -979,10 +979,22 @@ void nsSSLIOLayerHelpers::GlobalCleanup() { 
  MOZ_ASSERT(NS_IsMainThread(), "Not on main thread");



  if (gPrivateSSLIOLayerHelpers) {

    Preferences::RemoveObserver(gPrivateSSLIOLayerHelpers,

                                "security.tls.version.fallback-limit");

#ifdef DEBUG

    gPrivateSSLIOLayerHelpers->mRegisteredPrefObservers = false;

#endif

    gPrivateSSLIOLayerHelpers = nullptr;

  }



  if (gPublicSSLIOLayerHelpers) {

    Preferences::RemoveObserver(gPublicSSLIOLayerHelpers,

                                "security.tls.version.fallback-limit");

    Preferences::RemoveObserver(gPublicSSLIOLayerHelpers,

                                "security.tls.insecure_fallback_hosts");

#ifdef DEBUG

    gPublicSSLIOLayerHelpers->mRegisteredPrefObservers = false;

#endif

    gPublicSSLIOLayerHelpers = nullptr;

  }

}
@@ -1012,8 +1024,10 @@ static int32_t PlaintextRecv(PRFileDesc* fd, void* buf, int32_t amount, 
}



nsSSLIOLayerHelpers::~nsSSLIOLayerHelpers() {

  Preferences::RemoveObserver(this, "security.tls.version.fallback-limit");

  Preferences::RemoveObserver(this, "security.tls.insecure_fallback_hosts");

  // Pref observers must have been removed before destruction, since the

  // destructor may run off the main thread.

  MOZ_ASSERT(!mRegisteredPrefObservers,

             "Pref observers should have been removed before destruction");

}



template <typename R, R return_value, typename... Args>
@@ -1094,6 +1108,9 @@ nsresult nsSSLIOLayerHelpers::Init() { 
  if (NS_IsMainThread()) {

    initInsecureFallbackSites();



#ifdef DEBUG

    mRegisteredPrefObservers = true;

#endif

    Preferences::AddStrongObserver(this, "security.tls.version.fallback-limit");

    if (isPublic()) {

      // Changes to the allowlist on the public side will update the pref.

security/manager/ssl/nsNSSIOLayer.h

+3 −0
Original line number Diff line number Diff line
@@ -101,6 +101,9 @@ class nsSSLIOLayerHelpers : public nsIObserver { 


  mozilla::Mutex mutex MOZ_UNANNOTATED;

  uint32_t mTlsFlags;

#ifdef DEBUG

  bool mRegisteredPrefObservers = false;

#endif

};



namespace {