From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Piyush Mehrotra Date: Thu, 27 Jul 2023 19:35:14 +0000 Subject: [PATCH] Check caller's uid in backupAgentCreated callback AM.backupAgentCreated() should enforce that caller belongs the package called in the API. Bug: 289549315 Test: atest android.security.cts.ActivityManagerTest#testActivityManager_backupAgentCreated_rejectIfCallerUidNotEqualsPackageUid (cherry picked from https://googleplex-android-review.googlesource.com/q/commit:52b91363583c4e2b68f1a818b067cefe04809285) Merged-In: I9f3ae5ec0b8f00e020d471cc0eddf8bd8bdbb82d Change-Id: I9f3ae5ec0b8f00e020d471cc0eddf8bd8bdbb82d --- .../server/am/ActivityManagerService.java | 23 +++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java index ec8841debb7a..3e99e594a702 100644 --- a/services/core/java/com/android/server/am/ActivityManagerService.java +++ b/services/core/java/com/android/server/am/ActivityManagerService.java @@ -3136,6 +3136,22 @@ public class ActivityManagerService extends IActivityManager.Stub } } + /** + * Enforces that the uid of the caller matches the uid of the package. + * + * @param packageName the name of the package to match uid against. + * @param callingUid the uid of the caller. + * @throws SecurityException if the calling uid doesn't match uid of the package. + */ + private void enforceCallingPackage(String packageName, int callingUid) { + final int userId = UserHandle.getUserId(callingUid); + final int packageUid = getPackageManagerInternalLocked().getPackageUid(packageName, + /*flags=*/ 0, userId); + if (packageUid != callingUid) { + throw new SecurityException(packageName + " does not belong to uid " + callingUid); + } + } + @Override public void setPackageScreenCompatMode(String packageName, int mode) { mActivityTaskManager.setPackageScreenCompatMode(packageName, mode); @@ -14345,13 +14361,16 @@ public class ActivityManagerService extends IActivityManager.Stub // A backup agent has just come up @Override public void backupAgentCreated(String agentPackageName, IBinder agent, int userId) { + final int callingUid = Binder.getCallingUid(); + enforceCallingPackage(agentPackageName, callingUid); + // Resolve the target user id and enforce permissions. - userId = mUserController.handleIncomingUser(Binder.getCallingPid(), Binder.getCallingUid(), + userId = mUserController.handleIncomingUser(Binder.getCallingPid(), callingUid, userId, /* allowAll */ false, ALLOW_FULL_ONLY, "backupAgentCreated", null); if (DEBUG_BACKUP) { Slog.v(TAG_BACKUP, "backupAgentCreated: " + agentPackageName + " = " + agent + " callingUserId = " + UserHandle.getCallingUserId() + " userId = " + userId - + " callingUid = " + Binder.getCallingUid() + " uid = " + Process.myUid()); + + " callingUid = " + callingUid + " uid = " + Process.myUid()); } synchronized(this) {