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Merge changes from topic "deny-create-user-dirs"

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* changes:
  Zygote: relabel to either system_userdir_file or system_data_file
  BrightnessTracker: don't create stuff directly in /data/system_de
This commit is contained in:
Eric Biggers
2022-05-09 14:45:11 +00:00
committed by Gerrit Code Review
parent 0d0729a62f 5454379320
commit 350433edc8
3 changed files with 61 additions and 18 deletions
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41
core/jni/com_android_internal_os_Zygote.cpp
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@@ -1153,8 +1153,8 @@ static void relabelDir(const char* path, const char* context, fail_fn_t fail_fn)
}
}
// Relabel all directories under a path non-recursively.
static void relabelAllDirs(const char* path, const char* context, fail_fn_t fail_fn) {
// Relabel the subdirectories and symlinks in the given directory, non-recursively.
static void relabelSubdirs(const char* path, const char* context, fail_fn_t fail_fn) {
DIR* dir = opendir(path);
if (dir == nullptr) {
fail_fn(CREATE_ERROR("Failed to opendir %s", path));
@@ -1231,11 +1231,19 @@ static void isolateAppData(JNIEnv* env, const std::vector<std::string>& merged_d
snprintf(internalDePath, PATH_MAX, "/data/user_de");
snprintf(externalPrivateMountPath, PATH_MAX, "/mnt/expand");
char* dataDataContext = nullptr;
if (getfilecon(internalDePath, &dataDataContext) < 0) {
fail_fn(CREATE_ERROR("Unable to getfilecon on %s %s", internalDePath,
// Get the "u:object_r:system_userdir_file:s0" security context. This can be
// gotten from several different places; we use /data/user.
char* dataUserdirContext = nullptr;
if (getfilecon(internalCePath, &dataUserdirContext) < 0) {
fail_fn(CREATE_ERROR("Unable to getfilecon on %s %s", internalCePath,
strerror(errno)));
}
// Get the "u:object_r:system_data_file:s0" security context. This can be
// gotten from several different places; we use /data/misc.
char* dataFileContext = nullptr;
if (getfilecon("/data/misc", &dataFileContext) < 0) {
fail_fn(CREATE_ERROR("Unable to getfilecon on /data/misc %s", strerror(errno)));
}
MountAppDataTmpFs(internalLegacyCePath, fail_fn);
MountAppDataTmpFs(internalCePath, fail_fn);
@@ -1330,19 +1338,19 @@ static void isolateAppData(JNIEnv* env, const std::vector<std::string>& merged_d
// the file operations on tmpfs. If we set the label when we mount
// tmpfs, SELinux will not happy as we are changing system_data_files.
// Relabel dir under /data/user, including /data/user/0
relabelAllDirs(internalCePath, dataDataContext, fail_fn);
relabelSubdirs(internalCePath, dataFileContext, fail_fn);
// Relabel /data/user
relabelDir(internalCePath, dataDataContext, fail_fn);
relabelDir(internalCePath, dataUserdirContext, fail_fn);
// Relabel /data/data
relabelDir(internalLegacyCePath, dataDataContext, fail_fn);
relabelDir(internalLegacyCePath, dataFileContext, fail_fn);
// Relabel dir under /data/user_de
relabelAllDirs(internalDePath, dataDataContext, fail_fn);
// Relabel subdirectories of /data/user_de
relabelSubdirs(internalDePath, dataFileContext, fail_fn);
// Relabel /data/user_de
relabelDir(internalDePath, dataDataContext, fail_fn);
relabelDir(internalDePath, dataUserdirContext, fail_fn);
// Relabel CE and DE dirs under /mnt/expand
dir = opendir(externalPrivateMountPath);
@@ -1355,14 +1363,15 @@ static void isolateAppData(JNIEnv* env, const std::vector<std::string>& merged_d
auto cePath = StringPrintf("%s/user", volPath.c_str());
auto dePath = StringPrintf("%s/user_de", volPath.c_str());
relabelAllDirs(cePath.c_str(), dataDataContext, fail_fn);
relabelDir(cePath.c_str(), dataDataContext, fail_fn);
relabelAllDirs(dePath.c_str(), dataDataContext, fail_fn);
relabelDir(dePath.c_str(), dataDataContext, fail_fn);
relabelSubdirs(cePath.c_str(), dataFileContext, fail_fn);
relabelDir(cePath.c_str(), dataUserdirContext, fail_fn);
relabelSubdirs(dePath.c_str(), dataFileContext, fail_fn);
relabelDir(dePath.c_str(), dataUserdirContext, fail_fn);
}
closedir(dir);
freecon(dataDataContext);
freecon(dataUserdirContext);
freecon(dataFileContext);
}
static void insertPackagesToMergedList(JNIEnv* env,

32
services/core/java/com/android/server/display/BrightnessTracker.java
View File

@@ -505,12 +505,36 @@ public class BrightnessTracker {
}
}
// Return the path to the given file, either the new path
// /data/system/$filename, or the old path /data/system_de/$filename if the
// file exists there but not at the new path. Only use this for EVENTS_FILE
// and AMBIENT_BRIGHTNESS_STATS_FILE.
//
// Explanation: this service previously incorrectly stored these two files
// directly in /data/system_de, instead of in /data/system where they should
// have been. As system_server no longer has write access to
// /data/system_de itself, these files were moved to /data/system. To
// lazily migrate the files, we simply read from the old path if it exists
// and the new one doesn't, and always write to the new path. Note that
// system_server doesn't have permission to delete the old files.
private AtomicFile getFileWithLegacyFallback(String filename) {
AtomicFile file = mInjector.getFile(filename);
if (file != null && !file.exists()) {
AtomicFile legacyFile = mInjector.getLegacyFile(filename);
if (legacyFile != null && legacyFile.exists()) {
Slog.i(TAG, "Reading " + filename + " from old location");
return legacyFile;
}
}
return file;
}
private void readEvents() {
synchronized (mEventsLock) {
// Read might prune events so mark as dirty.
mEventsDirty = true;
mEvents.clear();
final AtomicFile readFrom = mInjector.getFile(EVENTS_FILE);
final AtomicFile readFrom = getFileWithLegacyFallback(EVENTS_FILE);
if (readFrom != null && readFrom.exists()) {
FileInputStream input = null;
try {
@@ -528,7 +552,7 @@ public class BrightnessTracker {
private void readAmbientBrightnessStats() {
mAmbientBrightnessStatsTracker = new AmbientBrightnessStatsTracker(mUserManager, null);
final AtomicFile readFrom = mInjector.getFile(AMBIENT_BRIGHTNESS_STATS_FILE);
final AtomicFile readFrom = getFileWithLegacyFallback(AMBIENT_BRIGHTNESS_STATS_FILE);
if (readFrom != null && readFrom.exists()) {
FileInputStream input = null;
try {
@@ -1095,6 +1119,10 @@ public class BrightnessTracker {
}
public AtomicFile getFile(String filename) {
return new AtomicFile(new File(Environment.getDataSystemDirectory(), filename));
}
public AtomicFile getLegacyFile(String filename) {
return new AtomicFile(new File(Environment.getDataSystemDeDirectory(), filename));
}

6
services/tests/servicestests/src/com/android/server/display/BrightnessTrackerTest.java
View File

@@ -1036,6 +1036,12 @@ public class BrightnessTrackerTest {
return null;
}
@Override
public AtomicFile getLegacyFile(String filename) {
// Don't have the test write / read from anywhere.
return null;
}
@Override
public long currentTimeMillis() {
return mCurrentTimeMillis;