Add safety checks on KEY_INTENT mismatch.
For many years, Parcel mismatch typed exploits has been using the
AccoungManagerService's passing of KEY_INTENT workflow, as a foothold of
launching arbitrary intents. We are adding an extra check on the service
side to simulate the final deserialization of the KEY_INTENT value, to
make sure the client side won't get a mismatched KEY_INTENT value.
Bug: 250588548
Bug: 240138294
Test: atest CtsAccountManagerTestCases
Test: local test, also see b/250588548
Change-Id: I433e34f6e21ce15c89825044a15b1dec46bb25cc
(cherry picked from commit ba27731d04d95bf4b17c41a5d85aac09c39b9329)
Merged-In: I433e34f6e21ce15c89825044a15b1dec46bb25cc
diff --git a/services/core/java/com/android/server/accounts/AccountManagerService.java b/services/core/java/com/android/server/accounts/AccountManagerService.java
index 6b731c3..c128b5e 100644
--- a/services/core/java/com/android/server/accounts/AccountManagerService.java
+++ b/services/core/java/com/android/server/accounts/AccountManagerService.java
@@ -89,6 +89,7 @@
import android.os.UserManager;
import android.stats.devicepolicy.DevicePolicyEnums;
import android.text.TextUtils;
+import android.util.EventLog;
import android.util.Log;
import android.util.Pair;
import android.util.Slog;
@@ -3100,7 +3101,7 @@
*/
if (!checkKeyIntent(
Binder.getCallingUid(),
- intent)) {
+ result)) {
onError(AccountManager.ERROR_CODE_INVALID_RESPONSE,
"invalid intent in bundle returned");
return;
@@ -3519,7 +3520,7 @@
&& (intent = result.getParcelable(AccountManager.KEY_INTENT)) != null) {
if (!checkKeyIntent(
Binder.getCallingUid(),
- intent)) {
+ result)) {
onError(AccountManager.ERROR_CODE_INVALID_RESPONSE,
"invalid intent in bundle returned");
return;
@@ -4870,7 +4871,13 @@
* into launching arbitrary intents on the device via by tricking to click authenticator
* supplied entries in the system Settings app.
*/
- protected boolean checkKeyIntent(int authUid, Intent intent) {
+ protected boolean checkKeyIntent(int authUid, Bundle bundle) {
+ if (!checkKeyIntentParceledCorrectly(bundle)) {
+ EventLog.writeEvent(0x534e4554, "250588548", authUid, "");
+ return false;
+ }
+
+ Intent intent = bundle.getParcelable(AccountManager.KEY_INTENT, Intent.class);
// Explicitly set an empty ClipData to ensure that we don't offer to
// promote any Uris contained inside for granting purposes
if (intent.getClipData() == null) {
@@ -4905,6 +4912,25 @@
}
}
+ /**
+ * Simulate the client side's deserialization of KEY_INTENT value, to make sure they don't
+ * violate our security policy.
+ *
+ * In particular we want to make sure the Authenticator doesn't trick users
+ * into launching arbitrary intents on the device via exploiting any other Parcel read/write
+ * mismatch problems.
+ */
+ private boolean checkKeyIntentParceledCorrectly(Bundle bundle) {
+ Parcel p = Parcel.obtain();
+ p.writeBundle(bundle);
+ p.setDataPosition(0);
+ Bundle simulateBundle = p.readBundle();
+ p.recycle();
+ Intent intent = bundle.getParcelable(AccountManager.KEY_INTENT, Intent.class);
+ return (intent.filterEquals(simulateBundle.getParcelable(AccountManager.KEY_INTENT,
+ Intent.class)));
+ }
+
private boolean isExportedSystemActivity(ActivityInfo activityInfo) {
String className = activityInfo.name;
return "android".equals(activityInfo.packageName) &&
@@ -5051,7 +5077,7 @@
&& (intent = result.getParcelable(AccountManager.KEY_INTENT)) != null) {
if (!checkKeyIntent(
Binder.getCallingUid(),
- intent)) {
+ result)) {
onError(AccountManager.ERROR_CODE_INVALID_RESPONSE,
"invalid intent in bundle returned");
return;
