Fix unnecessary redaction for videos in DCIM/Camera

The MediaMetadataRetriever (MMR) attempts to convert any legacy fds
obtained from a modern fd back to a modern fd. Access control is
implemented in the FuseDaemon by checking if the caller has an fd from
the FUSE fs and if so, it simply re-opens the associated file path and
returns the original (modern) fd to the caller.

The previous implementation was conservative and always opened a
redacted fd if an equivalent fd was found on the FUSE fs.
This breaks MMR location metadata access because location will always
be redacted when the data source is a file path or fd because the FUSE
fs will have an equivalent fd by the time convertToModernFd is called.

Now, we retrieve the redaction state of the equivalent opened FUSE fd
and use that to open the returned modern fd.

Test: atest TranscodeTest && atest fuse_node_test
Bug: 205749245

Change-Id: I45670dff4e5348a3b07bf423cd1465c328ad79ea

1 files changed, 26 insertions, 10 deletions

diff --git a/jni/com_android_providers_media_FuseDaemon.cpp b/jni/com_android_providers_media_FuseDaemon.cpp
index a73b0c9d3..78b193949 100644
--- a/jni/com_android_providers_media_FuseDaemon.cpp
+++ b/jni/com_android_providers_media_FuseDaemon.cpp
@@ -30,8 +30,11 @@
 namespace mediaprovider {
 namespace {
 
-constexpr const char* CLASS_NAME = "com/android/providers/media/fuse/FuseDaemon";
+constexpr const char* FUSE_DAEMON_CLASS_NAME = "com/android/providers/media/fuse/FuseDaemon";
+constexpr const char* FD_ACCESS_RESULT_CLASS_NAME = "com/android/providers/media/FdAccessResult";
 static jclass gFuseDaemonClass;
+static jclass gFdAccessResultClass;
+static jmethodID gFdAccessResultCtor;
 
 static std::vector<std::string> convert_object_array_to_string_vector(
         JNIEnv* env, jobjectArray java_object_array, const std::string& element_description) {
@@ -145,11 +148,13 @@ void com_android_providers_media_FuseDaemon_invalidate_fuse_dentry_cache(JNIEnv*
     // TODO(b/145741152): Throw exception
 }
 
-jstring com_android_providers_media_FuseDaemon_get_original_media_format_file_path(
-        JNIEnv* env, jobject self, jlong java_daemon, jint fd) {
+jobject com_android_providers_media_FuseDaemon_check_fd_access(JNIEnv* env, jobject self,
+                                                               jlong java_daemon, jint fd,
+                                                               jint uid) {
     fuse::FuseDaemon* const daemon = reinterpret_cast<fuse::FuseDaemon*>(java_daemon);
-    const std::string path = daemon->GetOriginalMediaFormatFilePath(fd);
-    return env->NewStringUTF(path.c_str());
+    const std::unique_ptr<fuse::FdAccessResult> result = daemon->CheckFdAccess(fd, uid);
+    return env->NewObject(gFdAccessResultClass, gFdAccessResultCtor,
+                          env->NewStringUTF(result->file_path.c_str()), result->should_redact);
 }
 
 void com_android_providers_media_FuseDaemon_initialize_device_id(JNIEnv* env, jobject self,
@@ -184,24 +189,35 @@ const JNINativeMethod methods[] = {
         {"native_invalidate_fuse_dentry_cache", "(JLjava/lang/String;)V",
          reinterpret_cast<void*>(
                  com_android_providers_media_FuseDaemon_invalidate_fuse_dentry_cache)},
-        {"native_get_original_media_format_file_path", "(JI)Ljava/lang/String;",
-         reinterpret_cast<void*>(
-                 com_android_providers_media_FuseDaemon_get_original_media_format_file_path)},
+        {"native_check_fd_access", "(JII)Lcom/android/providers/media/FdAccessResult;",
+         reinterpret_cast<void*>(com_android_providers_media_FuseDaemon_check_fd_access)},
         {"native_initialize_device_id", "(JLjava/lang/String;)V",
          reinterpret_cast<void*>(com_android_providers_media_FuseDaemon_initialize_device_id)}};
 }  // namespace
 
 void register_android_providers_media_FuseDaemon(JavaVM* vm, JNIEnv* env) {
-    gFuseDaemonClass = static_cast<jclass>(env->NewGlobalRef(env->FindClass(CLASS_NAME)));
+    gFuseDaemonClass =
+            static_cast<jclass>(env->NewGlobalRef(env->FindClass(FUSE_DAEMON_CLASS_NAME)));
+    gFdAccessResultClass =
+            static_cast<jclass>(env->NewGlobalRef(env->FindClass(FD_ACCESS_RESULT_CLASS_NAME)));
 
     if (gFuseDaemonClass == nullptr) {
-        LOG(FATAL) << "Unable to find class : " << CLASS_NAME;
+        LOG(FATAL) << "Unable to find class : " << FUSE_DAEMON_CLASS_NAME;
+    }
+
+    if (gFdAccessResultClass == nullptr) {
+        LOG(FATAL) << "Unable to find class : " << FD_ACCESS_RESULT_CLASS_NAME;
     }
 
     if (env->RegisterNatives(gFuseDaemonClass, methods, sizeof(methods) / sizeof(methods[0])) < 0) {
         LOG(FATAL) << "Unable to register native methods";
     }
 
+    gFdAccessResultCtor = env->GetMethodID(gFdAccessResultClass, "<init>", "(Ljava/lang/String;Z)V");
+    if (gFdAccessResultCtor == nullptr) {
+        LOG(FATAL) << "Unable to find ctor for FdAccessResult";
+    }
+
     fuse::MediaProviderWrapper::OneTimeInit(vm);
 }
 }  // namespace mediaprovider