Fix android.permission.CAPTURE_AUDIO_OUTPUT permission check

Make sure we use the correct PID and UID when checking
android.permission.CAPTURE_AUDIO_OUTPUT permission from audio
policy service.

Bug: 28772898
Change-Id: I8f0c45bf7a5728b4364a451eefb6c025892ae9a5
diff --git a/services/audioflinger/ServiceUtilities.cpp b/services/audioflinger/ServiceUtilities.cpp
index afc2440..3c73543 100644
--- a/services/audioflinger/ServiceUtilities.cpp
+++ b/services/audioflinger/ServiceUtilities.cpp
@@ -105,11 +105,10 @@
     return true;
 }
 
-bool captureAudioOutputAllowed() {
+bool captureAudioOutputAllowed(pid_t pid, uid_t uid) {
     if (getpid_cached == IPCThreadState::self()->getCallingPid()) return true;
     static const String16 sCaptureAudioOutput("android.permission.CAPTURE_AUDIO_OUTPUT");
-    // IMPORTANT: Use PermissionCache - not a runtime permission and may not change.
-    bool ok = PermissionCache::checkCallingPermission(sCaptureAudioOutput);
+    bool ok = checkPermission(sCaptureAudioOutput, pid, uid);
     if (!ok) ALOGE("Request requires android.permission.CAPTURE_AUDIO_OUTPUT");
     return ok;
 }
diff --git a/services/audioflinger/ServiceUtilities.h b/services/audioflinger/ServiceUtilities.h
index 1e79553..8b1bc00 100644
--- a/services/audioflinger/ServiceUtilities.h
+++ b/services/audioflinger/ServiceUtilities.h
@@ -21,7 +21,7 @@
 extern pid_t getpid_cached;
 bool isTrustedCallingUid(uid_t uid);
 bool recordingAllowed(const String16& opPackageName, pid_t pid, uid_t uid);
-bool captureAudioOutputAllowed();
+bool captureAudioOutputAllowed(pid_t pid, uid_t uid);
 bool captureHotwordAllowed();
 bool settingsAllowed();
 bool modifyAudioRoutingAllowed();
diff --git a/services/audiopolicy/service/AudioPolicyClientImplLegacy.cpp b/services/audiopolicy/service/AudioPolicyClientImplLegacy.cpp
index 09a931f..151d066 100644
--- a/services/audiopolicy/service/AudioPolicyClientImplLegacy.cpp
+++ b/services/audiopolicy/service/AudioPolicyClientImplLegacy.cpp
@@ -190,7 +190,8 @@
     }
 
     if (((*pDevices & AUDIO_DEVICE_IN_REMOTE_SUBMIX) == AUDIO_DEVICE_IN_REMOTE_SUBMIX)
-            && !captureAudioOutputAllowed()) {
+            && !captureAudioOutputAllowed(IPCThreadState::self()->getCallingPid(),
+                                          IPCThreadState::self()->getCallingUid())) {
         ALOGE("open_input() permission denied: capture not allowed");
         return AUDIO_IO_HANDLE_NONE;
     }
diff --git a/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp b/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
index 92a1285..02603b8 100644
--- a/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
+++ b/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
@@ -260,6 +260,7 @@
 status_t AudioPolicyService::getInputForAttr(const audio_attributes_t *attr,
                                              audio_io_handle_t *input,
                                              audio_session_t session,
+                                             pid_t pid,
                                              uid_t uid,
                                              uint32_t samplingRate,
                                              audio_format_t format,
@@ -282,11 +283,22 @@
     sp<AudioPolicyEffects>audioPolicyEffects;
     status_t status;
     AudioPolicyInterface::input_type_t inputType;
+
+    bool updatePid = (pid == -1);
     const uid_t callingUid = IPCThreadState::self()->getCallingUid();
-    if (!isTrustedCallingUid(callingUid) || uid == (uid_t)-1) {
-        ALOGW_IF(uid != (uid_t)-1 && uid != callingUid,
+    if (!isTrustedCallingUid(callingUid)) {
+        ALOGW_IF(uid != -1 && uid != (int)callingUid,
                 "%s uid %d tried to pass itself off as %d", __FUNCTION__, callingUid, uid);
         uid = callingUid;
+        updatePid = true;
+    }
+
+    if (updatePid) {
+        const pid_t callingPid = IPCThreadState::self()->getCallingPid();
+        ALOGW_IF(pid != -1 && pid != callingPid,
+                 "%s uid %d pid %d tried to pass itself off as pid %d",
+                 __func__, callingUid, callingPid, pid);
+        pid = callingPid;
     }
 
     {
@@ -306,7 +318,7 @@
             case AudioPolicyInterface::API_INPUT_TELEPHONY_RX:
                 // FIXME: use the same permission as for remote submix for now.
             case AudioPolicyInterface::API_INPUT_MIX_CAPTURE:
-                if (!captureAudioOutputAllowed()) {
+                if (!captureAudioOutputAllowed(pid, uid)) {
                     ALOGE("getInputForAttr() permission denied: capture not allowed");
                     status = PERMISSION_DENIED;
                 }
diff --git a/services/audiopolicy/service/AudioPolicyInterfaceImplLegacy.cpp b/services/audiopolicy/service/AudioPolicyInterfaceImplLegacy.cpp
index c830454..7c9315d 100644
--- a/services/audiopolicy/service/AudioPolicyInterfaceImplLegacy.cpp
+++ b/services/audiopolicy/service/AudioPolicyInterfaceImplLegacy.cpp
@@ -234,6 +234,7 @@
 status_t AudioPolicyService::getInputForAttr(const audio_attributes_t *attr,
                                              audio_io_handle_t *input,
                                              audio_session_t session,
+                                             pid_t pid __unused,
                                              uid_t uid __unused,
                                              uint32_t samplingRate,
                                              audio_format_t format,
diff --git a/services/audiopolicy/service/AudioPolicyService.h b/services/audiopolicy/service/AudioPolicyService.h
index 2710ac7..0b2cb35 100644
--- a/services/audiopolicy/service/AudioPolicyService.h
+++ b/services/audiopolicy/service/AudioPolicyService.h
@@ -99,6 +99,7 @@
     virtual status_t getInputForAttr(const audio_attributes_t *attr,
                                      audio_io_handle_t *input,
                                      audio_session_t session,
+                                     pid_t pid,
                                      uid_t uid,
                                      uint32_t samplingRate,
                                      audio_format_t format,