Fix permission check for audio recording

Define input types covering the different usecases for audio
  recording, and check the corresponding permissions when
  starting to record.
Move the permission check from audio flinger to audio policy,
  as only the policy has the information to determine which
  permission to enforce.
Fix missing permission when an application records audio
  and the audio is injected by an external policy.

Bug 18736417

Change-Id: If7ec040502242c990ac8ea464db484339bdce573
diff --git a/services/audiopolicy/AudioPolicyManager.cpp b/services/audiopolicy/AudioPolicyManager.cpp
index 744556d..a71aa53 100644
--- a/services/audiopolicy/AudioPolicyManager.cpp
+++ b/services/audiopolicy/AudioPolicyManager.cpp
@@ -1419,13 +1419,15 @@
                                              uint32_t samplingRate,
                                              audio_format_t format,
                                              audio_channel_mask_t channelMask,
-                                             audio_input_flags_t flags)
+                                             audio_input_flags_t flags,
+                                             input_type_t *inputType)
 {
     ALOGV("getInputForAttr() source %d, samplingRate %d, format %d, channelMask %x,"
             "session %d, flags %#x",
           attr->source, samplingRate, format, channelMask, session, flags);
 
     *input = AUDIO_IO_HANDLE_NONE;
+    *inputType = API_INPUT_INVALID;
     audio_devices_t device;
     // handle legacy remote submix case where the address was not always specified
     String8 address = String8("");
@@ -1447,6 +1449,7 @@
             return BAD_VALUE;
         }
         policyMix = &mPolicyMixes[index]->mMix;
+        *inputType = API_INPUT_MIX_EXT_POLICY_REROUTE;
     } else {
         device = getDeviceAndMixForInputSource(attr->source, &policyMix);
         if (device == AUDIO_DEVICE_NONE) {
@@ -1455,8 +1458,21 @@
         }
         if (policyMix != NULL) {
             address = policyMix->mRegistrationId;
+            if (policyMix->mMixType == MIX_TYPE_RECORDERS) {
+                // there is an external policy, but this input is attached to a mix of recorders,
+                // meaning it receives audio injected into the framework, so the recorder doesn't
+                // know about it and is therefore considered "legacy"
+                *inputType = API_INPUT_LEGACY;
+            } else {
+                // recording a mix of players defined by an external policy, we're rerouting for
+                // an external policy
+                *inputType = API_INPUT_MIX_EXT_POLICY_REROUTE;
+            }
         } else if (audio_is_remote_submix_device(device)) {
             address = String8("0");
+            *inputType = API_INPUT_MIX_CAPTURE;
+        } else {
+            *inputType = API_INPUT_LEGACY;
         }
         // adapt channel selection to input source
         switch (attr->source) {
@@ -1546,6 +1562,8 @@
     inputDesc->mIsSoundTrigger = isSoundTrigger;
     inputDesc->mPolicyMix = policyMix;
 
+    ALOGV("getInputForAttr() returns input type = %d", inputType);
+
     addInput(*input, inputDesc);
     mpClientInterface->onAudioPortListUpdate();
     return NO_ERROR;