DO NOT MERGE
[DO NOT MERGE] Don't allow permission change to runtime

Prevent apps to change permission protection level to dangerous
from any other type as this would allow a privilege escalation
where an app adds a normal permission in other app's group and
then redefines it as dangerous leading to the group auto-grant.

Test: Added a CTS test which passes.

Bug: 33860747

Change-Id: I4e86ee54e61d2fa45be601fae577986ef9a84673
(cherry picked from commit 8b943f40b6efc94490d79b1fe1bd7e6db0657eb0)

services/core/java/com/android/server/pm/PackageManagerService.java

diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 7654cc9..9d79325 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -12641,6 +12641,20 @@
                                     + perm.info.name + "; ignoring new declaration");
                             pkg.permissions.remove(i);
                         }
+                    } else if (!"android".equals(pkg.packageName)) {
+                        // Prevent apps to change protection level to dangerous from any other
+                        // type as this would allow a privilege escalation where an app adds a
+                        // normal/signature permission in other app's group and later redefines
+                        // it as dangerous leading to the group auto-grant.
+                        if ((perm.info.protectionLevel & PermissionInfo.PROTECTION_MASK_BASE)
+                                == PermissionInfo.PROTECTION_DANGEROUS) {
+                            if (bp != null && !bp.isRuntime()) {
+                                Slog.w(TAG, "Package " + pkg.packageName + " trying to change a "
+                                        + "non-runtime permission " + perm.info.name
+                                        + " to runtime; keeping old protection level");
+                                perm.info.protectionLevel = bp.protectionLevel;
+                            }
+                        }
                     }
                 }
             }