diff --git a/media/libaudioclient/IAudioFlinger.cpp b/media/libaudioclient/IAudioFlinger.cpp
index 5db60f3..56ddd4f 100644
--- a/media/libaudioclient/IAudioFlinger.cpp
+++ b/media/libaudioclient/IAudioFlinger.cpp
@@ -22,6 +22,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 
+#include <binder/IPCThreadState.h>
 #include <binder/Parcel.h>
 
 #include "IAudioFlinger.h"
@@ -836,6 +837,35 @@
 status_t BnAudioFlinger::onTransact(
     uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
 {
+    // make sure transactions reserved to AudioPolicyManager do not come from other processes
+    switch (code) {
+        case SET_STREAM_VOLUME:
+        case SET_STREAM_MUTE:
+        case SET_MODE:
+        case OPEN_OUTPUT:
+        case OPEN_DUPLICATE_OUTPUT:
+        case CLOSE_OUTPUT:
+        case SUSPEND_OUTPUT:
+        case RESTORE_OUTPUT:
+        case OPEN_INPUT:
+        case CLOSE_INPUT:
+        case INVALIDATE_STREAM:
+        case SET_VOICE_VOLUME:
+        case MOVE_EFFECTS:
+        case LOAD_HW_MODULE:
+        case LIST_AUDIO_PORTS:
+        case GET_AUDIO_PORT:
+        case CREATE_AUDIO_PATCH:
+        case RELEASE_AUDIO_PATCH:
+        case LIST_AUDIO_PATCHES:
+        case SET_AUDIO_PORT_CONFIG:
+            ALOGW("%s: transaction %d received from PID %d",
+                  __func__, code, IPCThreadState::self()->getCallingPid());
+            return INVALID_OPERATION;
+        default:
+            break;
+    }
+
     // Whitelist of relevant events to trigger log merging.
     // Log merging should activate during audio activity of any kind. This are considered the
     // most relevant events.
@@ -845,12 +875,8 @@
         case CREATE_RECORD:
         case SET_MASTER_VOLUME:
         case SET_MASTER_MUTE:
-        case SET_STREAM_VOLUME:
-        case SET_STREAM_MUTE:
         case SET_MIC_MUTE:
         case SET_PARAMETERS:
-        case OPEN_INPUT:
-        case SET_VOICE_VOLUME:
         case CREATE_EFFECT:
         case SYSTEM_READY: {
             requestLogMerge();
@@ -859,6 +885,7 @@
         default:
             break;
     }
+
     switch (code) {
         case CREATE_TRACK: {
             CHECK_INTERFACE(IAudioFlinger, data, reply);