1f93d9bca5
Bug: 279809333
Test: build
Change-Id: If6ef4c3b02d06212923e757fb68aa74e38c68db3
(cherry picked from commit 39dd515546)
82 lines
3.1 KiB
Text
82 lines
3.1 KiB
Text
# Fuseblk is a Filesystem in USErspace for block device. It should only be used
|
|
# to mount untrusted blocks like USB drives.
|
|
type fuseblkd_untrusted_exec, system_file_type, exec_type, file_type;
|
|
type fuseblkd_untrusted, domain;
|
|
|
|
typeattribute fuseblkd_untrusted coredomain;
|
|
|
|
domain_auto_trans(fuseblkd_untrusted, fuseblkd_exec, fuseblkd);
|
|
|
|
# Allow stdin/out back to vold.
|
|
allow fuseblkd_untrusted vold:fd use;
|
|
|
|
# Allows fuseblk to read block devices.
|
|
allow fuseblkd_untrusted block_device:dir search;
|
|
|
|
# Permissions to read dynamic partitions blocks.
|
|
allow fuseblkd_untrusted super_block_device:blk_file getattr;
|
|
|
|
# Permissions to access FUSE character devices.
|
|
allow fuseblkd_untrusted fuse_device:chr_file { getattr open read write };
|
|
|
|
# Permissions to access /mnt/media_rw/.
|
|
allow fuseblkd_untrusted mnt_media_rw_file:dir { getattr search };
|
|
allow fuseblkd_untrusted mnt_media_rw_stub_file:dir getattr;
|
|
|
|
# Permissions to read device mappers.
|
|
allow fuseblkd_untrusted sysfs_dm:dir search;
|
|
allow fuseblkd_untrusted sysfs_dm:file { getattr open read };
|
|
allow fuseblkd_untrusted dm_device:blk_file getattr;
|
|
|
|
# Permissions to read links in tmpfs.
|
|
allow fuseblkd_untrusted tmpfs:lnk_file read;
|
|
|
|
# Permissions to read loop device blocks.
|
|
allow fuseblkd_untrusted loop_device:blk_file getattr;
|
|
|
|
# Permissions to access the /proc/filesystems file.
|
|
allow fuseblkd_untrusted proc_filesystems:file { open read getattr };
|
|
|
|
###
|
|
### dontaudit rules
|
|
###
|
|
|
|
# ntfs-3g wants this permission to read a fork return code, for some reason.
|
|
# It's unclear why, because it still reads the fork return code correctly,
|
|
# and nothing breaks. If enforce is set to permissive, the audit goes away.
|
|
dontaudit fuseblkd_untrusted self:capability sys_admin;
|
|
|
|
###
|
|
### neverallow rules
|
|
###
|
|
|
|
# Fuseblk should never be run on block devices holding sensitive data.
|
|
neverallow fuseblkd_untrusted {
|
|
boot_block_device
|
|
frp_block_device
|
|
metadata_block_device
|
|
recovery_block_device
|
|
root_block_device
|
|
swap_block_device
|
|
system_block_device
|
|
userdata_block_device
|
|
cache_block_device
|
|
dm_device
|
|
}:blk_file no_rw_file_perms;
|
|
|
|
# Only allow entry from vold, and only through fuseblkd_untrusted_exec binaries.
|
|
neverallow { domain -vold } fuseblkd_untrusted:process transition;
|
|
neverallow * fuseblkd_untrusted:process dyntransition;
|
|
neverallow fuseblkd_untrusted { file_type fs_type -fuseblkd_untrusted_exec }:file entrypoint;
|
|
|
|
# Under no circumstances should fuseblkd_untrusted or any other fuseblk filesystem be
|
|
# given sys_admin access. They are fundementally untrusted, insecure filesystems.
|
|
# The correct solution here is to compartmentalize permissions correctly so that
|
|
# a smaller binary can get the required permissions. See fuseblkd.te.
|
|
# Similar to above, we don't need setgid or setuid permissions.
|
|
neverallow fuseblkd_untrusted self:capability { setgid setuid sys_admin };
|
|
neverallow fuseblkd_untrusted self:global_capability_class_set { setgid setuid sys_admin };
|
|
|
|
# Since we can't have sys_admin permissions, we definitely can't have mount/unmount
|
|
# permissions, since we won't be able to use them. Same with relabel permissions.
|
|
neverallow fuseblkd_untrusted fuseblk:filesystem { mount unmount relabelto relabelfrom};
|