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

1 files changed, 34 insertions, 4 deletions

diff --git a/services/audiopolicy/AudioPolicyInterfaceImpl.cpp b/services/audiopolicy/AudioPolicyInterfaceImpl.cpp
index d3c9013..a45dbb3 100644
--- a/services/audiopolicy/AudioPolicyInterfaceImpl.cpp
+++ b/services/audiopolicy/AudioPolicyInterfaceImpl.cpp
@@ -266,17 +266,47 @@ status_t AudioPolicyService::getInputForAttr(const audio_attributes_t *attr,
     }
     sp<AudioPolicyEffects>audioPolicyEffects;
     status_t status;
+    AudioPolicyInterface::input_type_t inputType;
     {
         Mutex::Autolock _l(mLock);
         // the audio_in_acoustics_t parameter is ignored by get_input()
         status = mAudioPolicyManager->getInputForAttr(attr, input, session,
                                                      samplingRate, format, channelMask,
-                                                     flags);
+                                                     flags, &inputType);
         audioPolicyEffects = mAudioPolicyEffects;
+
+        if (status == NO_ERROR) {
+            // enforce permission (if any) required for each type of input
+            switch (inputType) {
+            case AudioPolicyInterface::API_INPUT_LEGACY:
+                break;
+            case AudioPolicyInterface::API_INPUT_MIX_CAPTURE:
+                if (!captureAudioOutputAllowed()) {
+                    ALOGE("getInputForAttr() permission denied: capture not allowed");
+                    status = PERMISSION_DENIED;
+                }
+                break;
+            case AudioPolicyInterface::API_INPUT_MIX_EXT_POLICY_REROUTE:
+                if (!modifyAudioRoutingAllowed()) {
+                    ALOGE("getInputForAttr() permission denied: modify audio routing not allowed");
+                    status = PERMISSION_DENIED;
+                }
+                break;
+            case AudioPolicyInterface::API_INPUT_INVALID:
+            default:
+                LOG_ALWAYS_FATAL("getInputForAttr() encountered an invalid input type %d",
+                        (int)inputType);
+            }
+        }
+
+        if (status != NO_ERROR) {
+            if (status == PERMISSION_DENIED) {
+                mAudioPolicyManager->releaseInput(*input, session);
+            }
+            return status;
+        }
     }
-    if (status != NO_ERROR) {
-        return status;
-    }
+
     if (audioPolicyEffects != 0) {
         // create audio pre processors according to input source
         status_t status = audioPolicyEffects->addInputEffects(*input, attr->source, session);