1 files changed, 288 insertions, 0 deletions
diff --git a/security/manager/ssl/nsNSSShutDown.cpp b/security/manager/ssl/nsNSSShutDown.cpp
new file mode 100644
index 000000000..cffebac1e
--- /dev/null
+++ b/security/manager/ssl/nsNSSShutDown.cpp
@@ -0,0 +1,288 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsNSSShutDown.h"
+
+#include "mozilla/Casting.h"
+#include "nsCOMPtr.h"
+
+using namespace mozilla;
+
+extern LazyLogModule gPIPNSSLog;
+
+struct ObjectHashEntry : PLDHashEntryHdr {
+  nsNSSShutDownObject *obj;
+};
+
+static bool
+ObjectSetMatchEntry(const PLDHashEntryHdr *hdr, const void *key)
+{
+  const ObjectHashEntry *entry = static_cast<const ObjectHashEntry*>(hdr);
+  return entry->obj == static_cast<const nsNSSShutDownObject*>(key);
+}
+
+static void
+ObjectSetInitEntry(PLDHashEntryHdr *hdr, const void *key)
+{
+  ObjectHashEntry *entry = static_cast<ObjectHashEntry*>(hdr);
+  entry->obj = const_cast<nsNSSShutDownObject*>(static_cast<const nsNSSShutDownObject*>(key));
+}
+
+static const PLDHashTableOps gSetOps = {
+  PLDHashTable::HashVoidPtrKeyStub,
+  ObjectSetMatchEntry,
+  PLDHashTable::MoveEntryStub,
+  PLDHashTable::ClearEntryStub,
+  ObjectSetInitEntry
+};
+
+StaticMutex sListLock;
+Atomic<bool> sInShutdown(false);
+nsNSSShutDownList *singleton = nullptr;
+
+nsNSSShutDownList::nsNSSShutDownList()
+  : mObjects(&gSetOps, sizeof(ObjectHashEntry))
+  , mPK11LogoutCancelObjects(&gSetOps, sizeof(ObjectHashEntry))
+{
+}
+
+nsNSSShutDownList::~nsNSSShutDownList()
+{
+  PR_ASSERT(this == singleton);
+  singleton = nullptr;
+}
+
+void nsNSSShutDownList::remember(nsNSSShutDownObject *o)
+{
+  StaticMutexAutoLock lock(sListLock);
+  if (!nsNSSShutDownList::construct(lock)) {
+    return;
+  }
+
+  PR_ASSERT(o);
+  singleton->mObjects.Add(o, fallible);
+}
+
+void nsNSSShutDownList::forget(nsNSSShutDownObject *o)
+{
+  StaticMutexAutoLock lock(sListLock);
+  if (!singleton) {
+    return;
+  }
+
+  PR_ASSERT(o);
+  singleton->mObjects.Remove(o);
+}
+
+void nsNSSShutDownList::remember(nsOnPK11LogoutCancelObject *o)
+{
+  StaticMutexAutoLock lock(sListLock);
+  if (!nsNSSShutDownList::construct(lock)) {
+    return;
+  }
+
+  PR_ASSERT(o);
+  singleton->mPK11LogoutCancelObjects.Add(o, fallible);
+}
+
+void nsNSSShutDownList::forget(nsOnPK11LogoutCancelObject *o)
+{
+  StaticMutexAutoLock lock(sListLock);
+  if (!singleton) {
+    return;
+  }
+
+  PR_ASSERT(o);
+  singleton->mPK11LogoutCancelObjects.Remove(o);
+}
+
+nsresult nsNSSShutDownList::doPK11Logout()
+{
+  StaticMutexAutoLock lock(sListLock);
+  if (!singleton) {
+    return NS_OK;
+  }
+
+  MOZ_LOG(gPIPNSSLog, LogLevel::Debug,
+          ("canceling all open SSL sockets to disallow future IO\n"));
+
+  // During our iteration we will set a bunch of PRBools to true.
+  // Nobody else ever modifies that bool, only we do.
+  // We only must ensure that our objects do not go away.
+  // This is guaranteed by holding the list lock.
+
+  for (auto iter = singleton->mPK11LogoutCancelObjects.Iter();
+       !iter.Done();
+       iter.Next()) {
+    auto entry = static_cast<ObjectHashEntry*>(iter.Get());
+    nsOnPK11LogoutCancelObject* pklco =
+      BitwiseCast<nsOnPK11LogoutCancelObject*, nsNSSShutDownObject*>(entry->obj);
+    if (pklco) {
+      pklco->logout();
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNSSShutDownList::evaporateAllNSSResources()
+{
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  if (!NS_IsMainThread()) {
+    return NS_ERROR_NOT_SAME_THREAD;
+  }
+
+  StaticMutexAutoLock lock(sListLock);
+  // Other threads can acquire an nsNSSShutDownPreventionLock and cause this
+  // thread to block when it calls restructActivityToCurrentThread, below. If
+  // those other threads then attempt to create an object that must be
+  // remembered by the shut down list, they will call
+  // nsNSSShutDownList::remember, which attempts to acquire sListLock.
+  // Consequently, holding sListLock while we're in
+  // restrictActivityToCurrentThread would result in deadlock. sListLock
+  // protects the singleton, so if we enforce that the singleton only be created
+  // and destroyed on the main thread, and if we similarly enforce that this
+  // function is only called on the main thread, what we can do is check that
+  // the singleton hasn't already gone away and then we don't actually have to
+  // hold sListLock while calling restrictActivityToCurrentThread.
+  if (!singleton) {
+    return NS_OK;
+  }
+
+  {
+    StaticMutexAutoUnlock unlock(sListLock);
+    PRStatus rv = singleton->mActivityState.restrictActivityToCurrentThread();
+    if (rv != PR_SUCCESS) {
+      MOZ_LOG(gPIPNSSLog, LogLevel::Debug,
+              ("failed to restrict activity to current thread"));
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("now evaporating NSS resources"));
+
+  // Never free more than one entry, because other threads might be calling
+  // us and remove themselves while we are iterating over the list,
+  // and the behaviour of changing the list while iterating is undefined.
+  while (singleton) {
+    auto iter = singleton->mObjects.Iter();
+    if (iter.Done()) {
+      break;
+    }
+    auto entry = static_cast<ObjectHashEntry*>(iter.Get());
+    {
+      StaticMutexAutoUnlock unlock(sListLock);
+      entry->obj->shutdown(nsNSSShutDownObject::ShutdownCalledFrom::List);
+    }
+    iter.Remove();
+  }
+
+  if (!singleton) {
+    return NS_ERROR_FAILURE;
+  }
+
+  singleton->mActivityState.releaseCurrentThreadActivityRestriction();
+  return NS_OK;
+}
+
+void nsNSSShutDownList::enterActivityState()
+{
+  StaticMutexAutoLock lock(sListLock);
+  if (nsNSSShutDownList::construct(lock)) {
+    singleton->mActivityState.enter();
+  }
+}
+
+void nsNSSShutDownList::leaveActivityState()
+{
+  StaticMutexAutoLock lock(sListLock);
+  if (singleton) {
+    singleton->mActivityState.leave();
+  }
+}
+
+bool nsNSSShutDownList::construct(const StaticMutexAutoLock& /*proofOfLock*/)
+{
+  if (!singleton && !sInShutdown && XRE_IsParentProcess()) {
+    singleton = new nsNSSShutDownList();
+  }
+
+  return !!singleton;
+}
+
+void nsNSSShutDownList::shutdown()
+{
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  StaticMutexAutoLock lock(sListLock);
+  sInShutdown = true;
+
+  if (singleton) {
+    delete singleton;
+  }
+}
+
+nsNSSActivityState::nsNSSActivityState()
+:mNSSActivityStateLock("nsNSSActivityState.mNSSActivityStateLock"), 
+ mNSSActivityChanged(mNSSActivityStateLock,
+                     "nsNSSActivityState.mNSSActivityStateLock"),
+ mNSSActivityCounter(0),
+ mNSSRestrictedThread(nullptr)
+{
+}
+
+nsNSSActivityState::~nsNSSActivityState()
+{
+}
+
+void nsNSSActivityState::enter()
+{
+  MutexAutoLock lock(mNSSActivityStateLock);
+
+  while (mNSSRestrictedThread && mNSSRestrictedThread != PR_GetCurrentThread()) {
+    mNSSActivityChanged.Wait();
+  }
+
+  ++mNSSActivityCounter;
+}
+
+void nsNSSActivityState::leave()
+{
+  MutexAutoLock lock(mNSSActivityStateLock);
+
+  --mNSSActivityCounter;
+
+  mNSSActivityChanged.NotifyAll();
+}
+
+PRStatus nsNSSActivityState::restrictActivityToCurrentThread()
+{
+  MutexAutoLock lock(mNSSActivityStateLock);
+
+  while (mNSSActivityCounter > 0) {
+    mNSSActivityChanged.Wait(PR_TicksPerSecond());
+  }
+
+  mNSSRestrictedThread = PR_GetCurrentThread();
+
+  return PR_SUCCESS;
+}
+
+void nsNSSActivityState::releaseCurrentThreadActivityRestriction()
+{
+  MutexAutoLock lock(mNSSActivityStateLock);
+
+  mNSSRestrictedThread = nullptr;
+
+  mNSSActivityChanged.NotifyAll();
+}
+
+nsNSSShutDownPreventionLock::nsNSSShutDownPreventionLock()
+{
+  nsNSSShutDownList::enterActivityState();
+}
+
+nsNSSShutDownPreventionLock::~nsNSSShutDownPreventionLock()
+{
+  nsNSSShutDownList::leaveActivityState();
+}