From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Pranav Madapurmath Date: Wed, 5 Apr 2023 21:36:12 +0000 Subject: [PATCH] Resolve account image icon profile boundary exploit. Because Telecom grants the INTERACT_ACROSS_USERS permission, an exploit is possible where the user can upload an image icon (belonging to another user) via registering a phone account. This CL provides a lightweight solution for parsing the image URI to detect profile exploitation. Fixes: 273502295 Fixes: 296915211 Test: Unit test to enforce successful/failure path (cherry picked from commit d0d1d38e37de54e58a7532a0020582fbd7d476b7) (cherry picked from commit e7d0ca3fe5be6e393f643f565792ea5e7ed05f48) (cherry picked from https://googleplex-android-review.googlesource.com/q/commit:a604311f86ea8136ca2ac9f9ff0af7fa57ee3f42) Merged-In: I2b6418f019a373ee9f02ba8683e5b694e7ab80a5 Change-Id: I2b6418f019a373ee9f02ba8683e5b694e7ab80a5 --- .../server/telecom/TelecomServiceImpl.java | 22 +++++++++++++++++++ .../telecom/tests/TelecomServiceImplTest.java | 22 +++++++++++++++++++ 2 files changed, 44 insertions(+) diff --git a/src/com/android/server/telecom/TelecomServiceImpl.java b/src/com/android/server/telecom/TelecomServiceImpl.java index 2f9ffdbc4..4641f5436 100644 --- a/src/com/android/server/telecom/TelecomServiceImpl.java +++ b/src/com/android/server/telecom/TelecomServiceImpl.java @@ -35,6 +35,7 @@ import android.content.pm.PackageManager; import android.content.res.Resources; import android.content.pm.ParceledListSlice; import android.content.pm.ResolveInfo; +import android.graphics.drawable.Icon; import android.net.Uri; import android.os.Binder; import android.os.Bundle; @@ -468,6 +469,9 @@ public class TelecomServiceImpl { enforceRegisterMultiUser(); } enforceUserHandleMatchesCaller(account.getAccountHandle()); + // Validate the profile boundary of the given image URI. + validateAccountIconUserBoundary(account.getIcon()); + final long token = Binder.clearCallingIdentity(); try { mPhoneAccountRegistrar.registerPhoneAccount(account); @@ -1742,4 +1746,22 @@ public class TelecomServiceImpl { // If only TX or RX were set (or neither), the video state is valid. return remainingState == 0; } + + private void validateAccountIconUserBoundary(Icon icon) { + // Refer to Icon#getUriString for context. The URI string is invalid for icons of + // incompatible types. + if (icon != null && (icon.getType() == Icon.TYPE_URI + /*|| icon.getType() == Icon.TYPE_URI_ADAPTIVE_BITMAP*/)) { + String encodedUser = icon.getUri().getEncodedUserInfo(); + // If there is no encoded user, the URI is calling into the calling user space + if (encodedUser != null) { + int userId = Integer.parseInt(encodedUser); + if (userId != UserHandle.getUserId(Binder.getCallingUid())) { + // If we are transcending the profile boundary, throw an error. + throw new IllegalArgumentException("Attempting to register a phone account with" + + " an image icon belonging to another user."); + } + } + } + } } diff --git a/tests/src/com/android/server/telecom/tests/TelecomServiceImplTest.java b/tests/src/com/android/server/telecom/tests/TelecomServiceImplTest.java index 1d46f1abb..491b6183f 100644 --- a/tests/src/com/android/server/telecom/tests/TelecomServiceImplTest.java +++ b/tests/src/com/android/server/telecom/tests/TelecomServiceImplTest.java @@ -28,6 +28,7 @@ import android.content.Context; import android.content.Intent; import android.content.pm.ApplicationInfo; import android.content.pm.PackageManager; +import android.graphics.drawable.Icon; import android.net.Uri; import android.os.Binder; import android.os.Bundle; @@ -478,6 +479,27 @@ public class TelecomServiceImplTest extends TelecomTestCase { } } + @SmallTest + @Test + public void testRegisterPhoneAccountImageIconCrossUser() throws RemoteException { + String packageNameToUse = "com.android.officialpackage"; + PhoneAccountHandle phHandle = new PhoneAccountHandle(new ComponentName( + packageNameToUse, "cs"), "test", Binder.getCallingUserHandle()); + Icon icon = Icon.createWithContentUri("content://10@media/external/images/media/"); + PhoneAccount phoneAccount = makePhoneAccount(phHandle).setIcon(icon).build(); + doReturn(PackageManager.PERMISSION_GRANTED) + .when(mContext).checkCallingOrSelfPermission(MODIFY_PHONE_STATE); + + // This should fail; security exception will be thrown. + registerPhoneAccountTestHelper(phoneAccount, false); + + icon = Icon.createWithContentUri("content://0@media/external/images/media/"); + phoneAccount = makePhoneAccount(phHandle).setIcon(icon).build(); + // This should succeed. + registerPhoneAccountTestHelper(phoneAccount, true); + } + + @SmallTest public void testUnregisterPhoneAccount() throws RemoteException { String packageNameToUse = "com.android.officialpackage";