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, 26 insertions, 11 deletions

diff --git a/services/audioflinger/Effects.h b/services/audioflinger/Effects.h
index 6f93f81..4d53c0d 100644
--- a/services/audioflinger/Effects.h
+++ b/services/audioflinger/Effects.h
@@ -45,7 +45,8 @@ public:
                     const wp<AudioFlinger::EffectChain>& chain,
                     effect_descriptor_t *desc,
                     int id,
-                    int sessionId);
+                    audio_session_t sessionId,
+                    bool pinned);
     virtual ~EffectModule();
 
     enum effect_state {
@@ -93,8 +94,9 @@ public:
     const wp<ThreadBase>& thread() { return mThread; }
 
     status_t addHandle(EffectHandle *handle);
-    size_t disconnect(EffectHandle *handle, bool unpinIfLast);
-    size_t removeHandle(EffectHandle *handle);
+    ssize_t  disconnectHandle(EffectHandle *handle, bool unpinIfLast);
+    ssize_t removeHandle(EffectHandle *handle);
+    ssize_t removeHandle_l(EffectHandle *handle);
 
     const effect_descriptor_t& desc() const { return mDescriptor; }
     wp<EffectChain>&     chain() { return mChain; }
@@ -120,6 +122,7 @@ public:
     status_t         setOffloaded(bool offloaded, audio_io_handle_t io);
     bool             isOffloaded() const;
     void             addEffectToHal_l();
+    void             release_l();
 
     void             dump(int fd, const Vector<String16>& args);
 
@@ -204,12 +207,17 @@ public:
     bool enabled() const { return mEnabled; }
 
     // Getters
-    int id() const { return mEffect->id(); }
+    wp<EffectModule> effect() const { return mEffect; }
+    int id() const {
+        sp<EffectModule> effect = mEffect.promote();
+        if (effect == 0) {
+            return 0;
+        }
+        return effect->id();
+    }
     int priority() const { return mPriority; }
     bool hasControl() const { return mHasControl; }
-    sp<EffectModule> effect() const { return mEffect; }
-    // destroyed_l() must be called with the associated EffectModule mLock held
-    bool destroyed_l() const { return mDestroyed; }
+    bool disconnected() const { return mDisconnected; }
 
     void dumpToBuffer(char* buffer, size_t size);
 
@@ -218,7 +226,8 @@ protected:
     EffectHandle(const EffectHandle&);
     EffectHandle& operator =(const EffectHandle&);
 
-    sp<EffectModule> mEffect;           // pointer to controlled EffectModule
+    Mutex mLock;                        // protects IEffect method calls
+    wp<EffectModule> mEffect;           // pointer to controlled EffectModule
     sp<IEffectClient> mEffectClient;    // callback interface for client notifications
     /*const*/ sp<Client> mClient;       // client for shared memory allocation, see disconnect()
     sp<IMemory>         mCblkMemory;    // shared memory for control block
@@ -229,8 +238,7 @@ protected:
     bool mHasControl;                   // true if this handle is controlling the effect
     bool mEnabled;                      // cached enable state: needed when the effect is
                                         // restored after being suspended
-    bool mDestroyed;                    // Set to true by destructor. Access with EffectModule
-                                        // mLock held
+    bool mDisconnected;                 // Set to true by disconnect()
 };
 
 // the EffectChain class represents a group of effects associated to one audio session.
@@ -263,8 +271,15 @@ public:
         mLock.unlock();
     }
 
+    status_t createEffect_l(sp<EffectModule>& effect,
+                            ThreadBase *thread,
+                            effect_descriptor_t *desc,
+                            int id,
+                            audio_session_t sessionId,
+                            bool pinned);
     status_t addEffect_l(const sp<EffectModule>& handle);
-    size_t removeEffect_l(const sp<EffectModule>& handle);
+    status_t addEffect_ll(const sp<EffectModule>& handle);
+    size_t removeEffect_l(const sp<EffectModule>& handle, bool release = false);
 
     int sessionId() const { return mSessionId; }
     void setSessionId(int sessionId) { mSessionId = sessionId; }