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Commit ef62f3fc authored by Luis Hector Chavez's avatar Luis Hector Chavez
Browse files

Add a way to disable run-as at runtime 

This change adds the ro.boot.disable_runas system property, that when
set, disables the run-as command. This is done to reduce the surface
area of programs that have file based capabilities in Chrome OS, and
what they can do when running in non-developer mode.

Bug: 31630024
Test: run-as still works in aosp_sailfish
Test: run-as still works in Android in Chrome OS (in developer mode)
Change-Id: Iaf1d6f9ceb65081b7a9e17b9b91d8855e4080133
parent fc1cf907

run-as/Android.mk

+1 −1
Original line number Diff line number Diff line
@@ -3,6 +3,6 @@ LOCAL_PATH:= $(call my-dir) 
include $(CLEAR_VARS)

LOCAL_CFLAGS := -Wall -Werror

LOCAL_MODULE := run-as

LOCAL_SHARED_LIBRARIES := libselinux libpackagelistparser libminijail

LOCAL_SHARED_LIBRARIES := libbase libselinux libpackagelistparser libminijail

LOCAL_SRC_FILES := run-as.cpp

include $(BUILD_EXECUTABLE)

run-as/run-as.cpp

+8 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <libminijail.h>

#include <scoped_minijail.h>



#include <android-base/properties.h>

#include <packagelistparser/packagelistparser.h>

#include <private/android_filesystem_config.h>

#include <selinux/android.h>
@@ -40,6 +41,7 @@ 
//  The 'run-as' binary is installed with CAP_SETUID and CAP_SETGID file

//  capabilities, but will check the following:

//

//  - that the ro.boot.disable_runas property is not set

//  - that it is invoked from the 'shell' or 'root' user (abort otherwise)

//  - that '<package-name>' is the name of an installed and debuggable package

//  - that the package's data directory is well-formed
@@ -139,6 +141,12 @@ int main(int argc, char* argv[]) { 
    error(1, 0, "only 'shell' or 'root' users can run this program");

  }



  // Some devices can disable running run-as, such as Chrome OS when running in

  // non-developer mode.

  if (android::base::GetBoolProperty("ro.boot.disable_runas", false)) {

      error(1, 0, "run-as is disabled from the kernel commandline");

  }



  char* pkgname = argv[1];

  int cmd_argv_offset = 2;