1 # Life begins with the kernel. 2 type kernel, domain, mlstrustedsubject; 3 4 allow kernel self:capability sys_nice; 5 6 # Root fs. 7 r_dir_file(kernel, rootfs) 8 r_dir_file(kernel, proc) 9 10 # Get SELinux enforcing status. 11 allow kernel selinuxfs:dir r_dir_perms; 12 allow kernel selinuxfs:file r_file_perms; 13 14 # Get file contexts during first stage 15 allow kernel file_contexts_file:file r_file_perms; 16 17 # Allow init relabel itself. 18 allow kernel rootfs:file relabelfrom; 19 allow kernel init_exec:file relabelto; 20 # TODO: investigate why we need this. 21 allow kernel init:process share; 22 23 # cgroup filesystem initialization prior to setting the cgroup root directory label. 24 allow kernel unlabeled:dir search; 25 26 # Mount usbfs. 27 allow kernel usbfs:filesystem mount; 28 allow kernel usbfs:dir search; 29 30 # Initial setenforce by init prior to switching to init domain. 31 # We use dontaudit instead of allow to prevent a kernel spawned userspace 32 # process from turning off SELinux once enabled. 33 dontaudit kernel self:security setenforce; 34 35 # Write to /proc/1/oom_adj prior to switching to init domain. 36 allow kernel self:capability sys_resource; 37 38 # Init reboot before switching selinux domains under certain error 39 # conditions. Allow it. 40 # As part of rebooting, init writes "u" to /proc/sysrq-trigger to 41 # remount filesystems read-only. /data is not mounted at this point, 42 # so we could ignore this. For now, we allow it. 43 allow kernel self:capability sys_boot; 44 allow kernel proc_sysrq:file w_file_perms; 45 46 # Allow writing to /dev/kmsg which was created prior to loading policy. 47 allow kernel tmpfs:chr_file write; 48 49 # Set checkreqprot by init.rc prior to switching to init domain. 50 allow kernel selinuxfs:file write; 51 allow kernel self:security setcheckreqprot; 52 53 # kernel thread "loop0", used by the loop block device, for ASECs (b/17158723) 54 allow kernel sdcard_type:file { read write }; 55 56 # f_mtp driver accesses files from kernel context. 57 allow kernel mediaprovider:fd use; 58 59 # Allow the kernel to read OBB files from app directories. (b/17428116) 60 # Kernel thread "loop0" reads a vold supplied file descriptor. 61 # Fixes CTS tests: 62 # * android.os.storage.cts.StorageManagerTest#testMountAndUnmountObbNormal 63 # * android.os.storage.cts.StorageManagerTest#testMountAndUnmountTwoObbs 64 allow kernel vold:fd use; 65 allow kernel app_data_file:file read; 66 allow kernel asec_image_file:file read; 67 68 # Allow reading loop device in update_engine_unittests. (b/28319454) 69 userdebug_or_eng(` 70 allow kernel update_engine_data_file:file read; 71 allow kernel nativetest_data_file:file read; 72 ') 73 74 # Access to /data/media. 75 # This should be removed if sdcardfs is modified to alter the secontext for its 76 # accesses to the underlying FS. 77 allow kernel media_rw_data_file:dir create_dir_perms; 78 allow kernel media_rw_data_file:file create_file_perms; 79 80 # Access to /data/misc/vold/virtual_disk. 81 allow kernel vold_data_file:file read; 82 83 ### 84 ### neverallow rules 85 ### 86 87 # The initial task starts in the kernel domain (assigned via 88 # initial_sid_contexts), but nothing ever transitions to it. 89 neverallow * kernel:process { transition dyntransition }; 90 91 # The kernel domain is never entered via an exec, nor should it 92 # ever execute a program outside the rootfs without changing to another domain. 93 # If you encounter an execute_no_trans denial on the kernel domain, then 94 # possible causes include: 95 # - The program is a kernel usermodehelper. In this case, define a domain 96 # for the program and domain_auto_trans() to it. 97 # - You are running an exploit which switched to the init task credentials 98 # and is then trying to exec a shell or other program. You lose! 99 neverallow kernel *:file { entrypoint execute_no_trans }; 100 101 # the kernel should not be accessing files owned by other users. 102 # Instead of adding dac_{read_search,override}, fix the unix permissions 103 # on files being accessed. 104 neverallow kernel self:capability { dac_override dac_read_search }; 105
