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Protect userlist.xml and <user>.xml from corruption.

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Bug: 269072872
Bug: 253568736
Test: atest UserManagerServiceTest UserManagerServiceUserInfoTest
Change-Id: I7aa9858731f60f80d1538f40fec765316b691c2d
This commit is contained in:
Alex Buynytskyy
2023-03-27 20:44:21 -07:00
parent 69b03326bc
commit 241529cb52
1 changed files with 179 additions and 119 deletions
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298
services/core/java/com/android/server/pm/UserManagerService.java
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@@ -278,6 +278,7 @@ public class UserManagerService extends IUserManager.Stub {
private static final long EPOCH_PLUS_30_YEARS = 30L * 365 * 24 * 60 * 60 * 1000L; // ms
static final int WRITE_USER_MSG = 1;
static final int WRITE_USER_LIST_MSG = 2;
static final int WRITE_USER_DELAY = 2*1000; // 2 seconds
private static final long BOOT_USER_SET_TIMEOUT_MS = 300_000;
@@ -321,7 +322,6 @@ public class UserManagerService extends IUserManager.Stub {
private final Handler mHandler;
private final File mUsersDir;
@GuardedBy("mPackagesLock")
private final File mUserListFile;
private final IBinder mUserRestrictionToken = new Binder();
@@ -3623,77 +3623,95 @@ public class UserManagerService extends IUserManager.Stub {
mUpdatingSystemUserMode = true;
}
private ResilientAtomicFile getUserListFile() {
File tempBackup = new File(mUserListFile.getParent(), mUserListFile.getName() + ".backup");
File reserveCopy = new File(mUserListFile.getParent(),
mUserListFile.getName() + ".reservecopy");
int fileMode = FileUtils.S_IRWXU | FileUtils.S_IRWXG | FileUtils.S_IXOTH;
return new ResilientAtomicFile(mUserListFile, tempBackup, reserveCopy, fileMode,
"user list", (priority, msg) -> {
Slog.e(LOG_TAG, msg);
// Something went wrong, schedule full rewrite.
scheduleWriteUserList();
});
}
@GuardedBy({"mPackagesLock"})
private void readUserListLP() {
if (!mUserListFile.exists()) {
fallbackToSingleUserLP();
return;
}
FileInputStream fis = null;
AtomicFile userListFile = new AtomicFile(mUserListFile);
try {
fis = userListFile.openRead();
final TypedXmlPullParser parser = Xml.resolvePullParser(fis);
int type;
while ((type = parser.next()) != XmlPullParser.START_TAG
&& type != XmlPullParser.END_DOCUMENT) {
// Skip
}
try (ResilientAtomicFile file = getUserListFile()) {
FileInputStream fin = null;
try {
fin = file.openRead();
if (fin == null) {
Slog.e(LOG_TAG, "userlist.xml not found, fallback to single user");
fallbackToSingleUserLP();
return;
}
if (type != XmlPullParser.START_TAG) {
Slog.e(LOG_TAG, "Unable to read user list");
fallbackToSingleUserLP();
return;
}
final TypedXmlPullParser parser = Xml.resolvePullParser(fin);
int type;
while ((type = parser.next()) != XmlPullParser.START_TAG
&& type != XmlPullParser.END_DOCUMENT) {
// Skip
}
mNextSerialNumber = -1;
if (parser.getName().equals(TAG_USERS)) {
mNextSerialNumber =
parser.getAttributeInt(null, ATTR_NEXT_SERIAL_NO, mNextSerialNumber);
mUserVersion =
parser.getAttributeInt(null, ATTR_USER_VERSION, mUserVersion);
mUserTypeVersion =
parser.getAttributeInt(null, ATTR_USER_TYPE_VERSION, mUserTypeVersion);
}
if (type != XmlPullParser.START_TAG) {
Slog.e(LOG_TAG, "Unable to read user list");
fallbackToSingleUserLP();
return;
}
while ((type = parser.next()) != XmlPullParser.END_DOCUMENT) {
if (type == XmlPullParser.START_TAG) {
final String name = parser.getName();
if (name.equals(TAG_USER)) {
UserData userData = readUserLP(parser.getAttributeInt(null, ATTR_ID));
mNextSerialNumber = -1;
if (parser.getName().equals(TAG_USERS)) {
mNextSerialNumber =
parser.getAttributeInt(null, ATTR_NEXT_SERIAL_NO, mNextSerialNumber);
mUserVersion =
parser.getAttributeInt(null, ATTR_USER_VERSION, mUserVersion);
mUserTypeVersion =
parser.getAttributeInt(null, ATTR_USER_TYPE_VERSION, mUserTypeVersion);
}
if (userData != null) {
synchronized (mUsersLock) {
mUsers.put(userData.info.id, userData);
if (mNextSerialNumber < 0
|| mNextSerialNumber <= userData.info.id) {
mNextSerialNumber = userData.info.id + 1;
}
}
}
} else if (name.equals(TAG_GUEST_RESTRICTIONS)) {
while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
&& type != XmlPullParser.END_TAG) {
if (type == XmlPullParser.START_TAG) {
if (parser.getName().equals(TAG_RESTRICTIONS)) {
synchronized (mGuestRestrictions) {
UserRestrictionsUtils
.readRestrictions(parser, mGuestRestrictions);
while ((type = parser.next()) != XmlPullParser.END_DOCUMENT) {
if (type == XmlPullParser.START_TAG) {
final String name = parser.getName();
if (name.equals(TAG_USER)) {
UserData userData = readUserLP(parser.getAttributeInt(null, ATTR_ID));
if (userData != null) {
synchronized (mUsersLock) {
mUsers.put(userData.info.id, userData);
if (mNextSerialNumber < 0
|| mNextSerialNumber <= userData.info.id) {
mNextSerialNumber = userData.info.id + 1;
}
}
break;
}
} else if (name.equals(TAG_GUEST_RESTRICTIONS)) {
while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
&& type != XmlPullParser.END_TAG) {
if (type == XmlPullParser.START_TAG) {
if (parser.getName().equals(TAG_RESTRICTIONS)) {
synchronized (mGuestRestrictions) {
UserRestrictionsUtils
.readRestrictions(parser, mGuestRestrictions);
}
}
break;
}
}
}
}
}
}
updateUserIds();
upgradeIfNecessaryLP();
} catch (IOException | XmlPullParserException e) {
fallbackToSingleUserLP();
} finally {
IoUtils.closeQuietly(fis);
updateUserIds();
upgradeIfNecessaryLP();
} catch (Exception e) {
// Remove corrupted file and retry.
file.failRead(fin, e);
readUserListLP();
return;
}
}
synchronized (mUsersLock) {
@@ -4099,6 +4117,18 @@ public class UserManagerService extends IUserManager.Stub {
}
}
private void scheduleWriteUserList() {
if (DBG) {
debug("scheduleWriteUserList");
}
// No need to wrap it within a lock -- worst case, we'll just post the same message
// twice.
if (!mHandler.hasMessages(WRITE_USER_LIST_MSG)) {
Message msg = mHandler.obtainMessage(WRITE_USER_LIST_MSG);
mHandler.sendMessageDelayed(msg, WRITE_USER_DELAY);
}
}
private void scheduleWriteUser(UserData userData) {
if (DBG) {
debug("scheduleWriteUser");
@@ -4111,20 +4141,37 @@ public class UserManagerService extends IUserManager.Stub {
}
}
private ResilientAtomicFile getUserFile(int userId) {
File file = new File(mUsersDir, userId + XML_SUFFIX);
File tempBackup = new File(mUsersDir, userId + XML_SUFFIX + ".backup");
File reserveCopy = new File(mUsersDir, userId + XML_SUFFIX + ".reservecopy");
int fileMode = FileUtils.S_IRWXU | FileUtils.S_IRWXG | FileUtils.S_IXOTH;
return new ResilientAtomicFile(file, tempBackup, reserveCopy, fileMode,
"user info", (priority, msg) -> {
Slog.e(LOG_TAG, msg);
// Something went wrong, schedule full rewrite.
UserData userData = getUserDataNoChecks(userId);
if (userData != null) {
scheduleWriteUser(userData);
}
});
}
@GuardedBy({"mPackagesLock"})
private void writeUserLP(UserData userData) {
if (DBG) {
debug("writeUserLP " + userData);
}
FileOutputStream fos = null;
AtomicFile userFile = new AtomicFile(new File(mUsersDir, userData.info.id + XML_SUFFIX));
try {
fos = userFile.startWrite();
writeUserLP(userData, fos);
userFile.finishWrite(fos);
} catch (Exception ioe) {
Slog.e(LOG_TAG, "Error writing user info " + userData.info.id, ioe);
userFile.failWrite(fos);
try (ResilientAtomicFile userFile = getUserFile(userData.info.id)) {
FileOutputStream fos = null;
try {
fos = userFile.startWrite();
writeUserLP(userData, fos);
userFile.finishWrite(fos);
} catch (Exception ioe) {
Slog.e(LOG_TAG, "Error writing user info " + userData.info.id, ioe);
userFile.failWrite(fos);
}
}
}
@@ -4253,65 +4300,71 @@ public class UserManagerService extends IUserManager.Stub {
if (DBG) {
debug("writeUserList");
}
FileOutputStream fos = null;
AtomicFile userListFile = new AtomicFile(mUserListFile);
try {
fos = userListFile.startWrite();
final TypedXmlSerializer serializer = Xml.resolveSerializer(fos);
serializer.startDocument(null, true);
serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
serializer.startTag(null, TAG_USERS);
serializer.attributeInt(null, ATTR_NEXT_SERIAL_NO, mNextSerialNumber);
serializer.attributeInt(null, ATTR_USER_VERSION, mUserVersion);
serializer.attributeInt(null, ATTR_USER_TYPE_VERSION, mUserTypeVersion);
try (ResilientAtomicFile file = getUserListFile()) {
FileOutputStream fos = null;
try {
fos = file.startWrite();
serializer.startTag(null, TAG_GUEST_RESTRICTIONS);
synchronized (mGuestRestrictions) {
UserRestrictionsUtils
.writeRestrictions(serializer, mGuestRestrictions, TAG_RESTRICTIONS);
}
serializer.endTag(null, TAG_GUEST_RESTRICTIONS);
int[] userIdsToWrite;
synchronized (mUsersLock) {
userIdsToWrite = new int[mUsers.size()];
for (int i = 0; i < userIdsToWrite.length; i++) {
UserInfo user = mUsers.valueAt(i).info;
userIdsToWrite[i] = user.id;
final TypedXmlSerializer serializer = Xml.resolveSerializer(fos);
serializer.startDocument(null, true);
serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output",
true);
serializer.startTag(null, TAG_USERS);
serializer.attributeInt(null, ATTR_NEXT_SERIAL_NO, mNextSerialNumber);
serializer.attributeInt(null, ATTR_USER_VERSION, mUserVersion);
serializer.attributeInt(null, ATTR_USER_TYPE_VERSION, mUserTypeVersion);
serializer.startTag(null, TAG_GUEST_RESTRICTIONS);
synchronized (mGuestRestrictions) {
UserRestrictionsUtils
.writeRestrictions(serializer, mGuestRestrictions, TAG_RESTRICTIONS);
}
serializer.endTag(null, TAG_GUEST_RESTRICTIONS);
int[] userIdsToWrite;
synchronized (mUsersLock) {
userIdsToWrite = new int[mUsers.size()];
for (int i = 0; i < userIdsToWrite.length; i++) {
UserInfo user = mUsers.valueAt(i).info;
userIdsToWrite[i] = user.id;
}
}
for (int id : userIdsToWrite) {
serializer.startTag(null, TAG_USER);
serializer.attributeInt(null, ATTR_ID, id);
serializer.endTag(null, TAG_USER);
}
}
for (int id : userIdsToWrite) {
serializer.startTag(null, TAG_USER);
serializer.attributeInt(null, ATTR_ID, id);
serializer.endTag(null, TAG_USER);
}
serializer.endTag(null, TAG_USERS);
serializer.endTag(null, TAG_USERS);
serializer.endDocument();
userListFile.finishWrite(fos);
} catch (Exception e) {
userListFile.failWrite(fos);
Slog.e(LOG_TAG, "Error writing user list");
serializer.endDocument();
file.finishWrite(fos);
} catch (Exception e) {
Slog.e(LOG_TAG, "Error writing user list", e);
file.failWrite(fos);
}
}
}
@GuardedBy({"mPackagesLock"})
private UserData readUserLP(int id) {
FileInputStream fis = null;
try {
AtomicFile userFile =
new AtomicFile(new File(mUsersDir, Integer.toString(id) + XML_SUFFIX));
fis = userFile.openRead();
return readUserLP(id, fis);
} catch (IOException ioe) {
Slog.e(LOG_TAG, "Error reading user list");
} catch (XmlPullParserException pe) {
Slog.e(LOG_TAG, "Error reading user list");
} finally {
IoUtils.closeQuietly(fis);
try (ResilientAtomicFile file = getUserFile(id)) {
FileInputStream fis = null;
try {
fis = file.openRead();
if (fis == null) {
Slog.e(LOG_TAG, "User info not found, returning null, user id: " + id);
return null;
}
return readUserLP(id, fis);
} catch (Exception e) {
// Remove corrupted file and retry.
Slog.e(LOG_TAG, "Error reading user info, user id: " + id);
file.failRead(fis, e);
return readUserLP(id);
}
}
return null;
}
@GuardedBy({"mPackagesLock"})
@@ -5805,9 +5858,8 @@ public class UserManagerService extends IUserManager.Stub {
synchronized (mPackagesLock) {
writeUserListLP();
}
// Remove user file
AtomicFile userFile = new AtomicFile(new File(mUsersDir, userId + XML_SUFFIX));
userFile.delete();
// Remove user file(s)
getUserFile(userId).delete();
updateUserIds();
if (RELEASE_DELETED_USER_ID) {
synchronized (mUsersLock) {
@@ -6770,6 +6822,13 @@ public class UserManagerService extends IUserManager.Stub {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case WRITE_USER_LIST_MSG: {
removeMessages(WRITE_USER_LIST_MSG);
synchronized (mPackagesLock) {
writeUserListLP();
}
break;
}
case WRITE_USER_MSG:
removeMessages(WRITE_USER_MSG, msg.obj);
synchronized (mPackagesLock) {
@@ -6782,6 +6841,7 @@ public class UserManagerService extends IUserManager.Stub {
+ ", it was probably removed before handler could handle it");
}
}
break;
}
}
}