DO NOT MERGE - improve audio effect framwework thread safety

- Reorganize handle effect creation code to make sure the effect engine
is created with both thread and effect chain mutex held.
- Reorganize handle disconnect code to make sure the effect engine
is released with both thread and effect chain mutex held.
- Protect IEffect interface methods in EffectHande with a Mutex.
- Only pin effect if the session was acquired first.
- Do not use strong pointer to EffectModule in EffectHandles:
only the EffectChain has a single strong reference to the EffectModule.

Bug: 32707507

CVE-2017-0479
CVE-2017-0480
CVE-2017-0499

Change-Id: Ia1098cba2cd32cc2d1c9dfdff4adc2388dfed80e
(cherry picked from commit b378b73dd7480b584340b8028802c9ca2d625123)
(cherry picked from commit 22e26d8ee73488c58ba3e7928e5da155151abfd0
 with backport by <sultanxda@gmail.com>)

1 files changed, 33 insertions, 18 deletions

diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index e5e8bdb..d7c9c47 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -1159,7 +1159,8 @@ sp<AudioFlinger::EffectHandle> AudioFlinger::ThreadBase::createEffect_l(
         int sessionId,
         effect_descriptor_t *desc,
         int *enabled,
-        status_t *status)
+        status_t *status,
+        bool pinned)
 {
     sp<EffectModule> effect;
     sp<EffectHandle> handle;
@@ -1253,20 +1254,7 @@ sp<AudioFlinger::EffectHandle> AudioFlinger::ThreadBase::createEffect_l(
             }
             effectRegistered = true;
             // create a new effect module if none present in the chain
-            effect = new EffectModule(this, chain, desc, id, sessionId);
-            lStatus = effect->status();
-            if (lStatus != NO_ERROR) {
-                goto Exit;
-            }
-
-            bool setVal = false;
-            if (mType == OFFLOAD || (mType == DIRECT && mIsDirectPcm)) {
-                setVal = true;
-            }
-
-            effect->setOffloaded(setVal, mId);
-
-            lStatus = chain->addEffect_l(effect);
+            lStatus = chain->createEffect_l(effect, this, desc, id, (audio_session_t)sessionId, pinned);
             if (lStatus != NO_ERROR) {
                 goto Exit;
             }
@@ -1307,6 +1295,33 @@ Exit:
     return handle;
 }
 
+void AudioFlinger::ThreadBase::disconnectEffectHandle(EffectHandle *handle,
+                                                      bool unpinIfLast)
+{
+    bool remove = false;
+    sp<EffectModule> effect;
+    {
+        Mutex::Autolock _l(mLock);
+
+        effect = handle->effect().promote();
+        if (effect == 0) {
+            return;
+        }
+        // restore suspended effects if the disconnected handle was enabled and the last one.
+        remove = (effect->removeHandle(handle) == 0) && (!effect->isPinned() || unpinIfLast);
+        if (remove) {
+            removeEffect_l(effect, true);
+        }
+    }
+    if (remove) {
+        mAudioFlinger->updateOrphanEffectChains(effect);
+        AudioSystem::unregisterEffect(effect->id());
+        if (handle->enabled()) {
+            checkSuspendOnEffectEnabled(effect, false, effect->sessionId());
+        }
+    }
+}
+
 sp<AudioFlinger::EffectModule> AudioFlinger::ThreadBase::getEffect(int sessionId, int effectId)
 {
     Mutex::Autolock _l(mLock);
@@ -1371,9 +1386,9 @@ status_t AudioFlinger::ThreadBase::addEffect_l(const sp<EffectModule>& effect)
     return NO_ERROR;
 }
 
-void AudioFlinger::ThreadBase::removeEffect_l(const sp<EffectModule>& effect) {
+void AudioFlinger::ThreadBase::removeEffect_l(const sp<EffectModule>& effect, bool release) {
 
-    ALOGV("removeEffect_l() %p effect %p", this, effect.get());
+    ALOGV("%s %p effect %p", __FUNCTION__, this, effect.get());
     effect_descriptor_t desc = effect->desc();
     if ((desc.flags & EFFECT_FLAG_TYPE_MASK) == EFFECT_FLAG_TYPE_AUXILIARY) {
         detachAuxEffect_l(effect->id());
@@ -1382,7 +1397,7 @@ void AudioFlinger::ThreadBase::removeEffect_l(const sp<EffectModule>& effect) {
     sp<EffectChain> chain = effect->chain().promote();
     if (chain != 0) {
         // remove effect chain if removing last effect
-        if (chain->removeEffect_l(effect) == 0) {
+        if (chain->removeEffect_l(effect, release) == 0) {
             removeEffectChain_l(chain);
         }
     } else {