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

5 files changed, 74 insertions, 7 deletions

diff --git a/services/audiopolicy/AudioPolicyClientImplLegacy.cpp b/services/audiopolicy/AudioPolicyClientImplLegacy.cpp
index 97719da..a79f8ae 100644
--- a/services/audiopolicy/AudioPolicyClientImplLegacy.cpp
+++ b/services/audiopolicy/AudioPolicyClientImplLegacy.cpp
@@ -188,6 +188,13 @@ static audio_io_handle_t open_input(audio_module_handle_t module,
     if (pSamplingRate == NULL || pFormat == NULL || pChannelMask == NULL || pDevices == NULL) {
         return AUDIO_IO_HANDLE_NONE;
     }
+
+    if (((*pDevices & AUDIO_DEVICE_IN_REMOTE_SUBMIX) == AUDIO_DEVICE_IN_REMOTE_SUBMIX)
+            && !captureAudioOutputAllowed()) {
+        ALOGE("open_input() permission denied: capture not allowed");
+        return AUDIO_IO_HANDLE_NONE;
+    }
+
     audio_config_t config = AUDIO_CONFIG_INITIALIZER;;
     config.sample_rate = *pSamplingRate;
     config.format = *pFormat;
diff --git a/services/audiopolicy/AudioPolicyInterface.h b/services/audiopolicy/AudioPolicyInterface.h
index 2826cad..4508fa7 100644
--- a/services/audiopolicy/AudioPolicyInterface.h
+++ b/services/audiopolicy/AudioPolicyInterface.h
@@ -57,6 +57,16 @@ class AudioPolicyInterface
 {
 
 public:
+    typedef enum {
+        API_INPUT_INVALID = -1,
+        API_INPUT_LEGACY  = 0,// e.g. audio recording from a microphone
+        API_INPUT_MIX_CAPTURE,// used for "remote submix", capture of the media to play it remotely
+        API_INPUT_MIX_EXT_POLICY_REROUTE,// used for platform audio rerouting, where mixes are
+                                         // handled by external and dynamically installed
+                                         // policies which reroute audio mixes
+    } input_type_t;
+
+public:
     virtual ~AudioPolicyInterface() {}
     //
     // configuration functions
@@ -120,7 +130,8 @@ public:
                                      uint32_t samplingRate,
                                      audio_format_t format,
                                      audio_channel_mask_t channelMask,
-                                     audio_input_flags_t flags) = 0;
+                                     audio_input_flags_t flags,
+                                     input_type_t *inputType) = 0;
     // indicates to the audio policy manager that the input starts being used.
     virtual status_t startInput(audio_io_handle_t input,
                                 audio_session_t session) = 0;
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);
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 @@ status_t AudioPolicyManager::getInputForAttr(const audio_attributes_t *attr,
                                              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 @@ status_t AudioPolicyManager::getInputForAttr(const audio_attributes_t *attr,
             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 @@ status_t AudioPolicyManager::getInputForAttr(const audio_attributes_t *attr,
         }
         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 @@ status_t AudioPolicyManager::getInputForAttr(const audio_attributes_t *attr,
     inputDesc->mIsSoundTrigger = isSoundTrigger;
     inputDesc->mPolicyMix = policyMix;
 
+    ALOGV("getInputForAttr() returns input type = %d", inputType);
+
     addInput(*input, inputDesc);
     mpClientInterface->onAudioPortListUpdate();
     return NO_ERROR;
diff --git a/services/audiopolicy/AudioPolicyManager.h b/services/audiopolicy/AudioPolicyManager.h
index ff3afab..4c976a3 100644
--- a/services/audiopolicy/AudioPolicyManager.h
+++ b/services/audiopolicy/AudioPolicyManager.h
@@ -112,7 +112,8 @@ public:
                                          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);
 
         // indicates to the audio policy manager that the input starts being used.
         virtual status_t startInput(audio_io_handle_t input,