platform_system_sepolicy/public/fsck.te
David Anderson 8a525d768f Fix e2fsck denials introduced by latest e2fsprogs merge.
This resulted from changes in e2fsprogs logic which traverses
/proc/mounts to warn about fixing a mounted filesystem.

Denials:

        07-08 15:08:21.207   853   853 I auditd  : type=1400 audit(0.0:88): avc: denied { getattr } for comm="e2fsck" path="/metadata" dev="vda12" ino=2 scontext=u:r:fsck:s0 tcontext=u:object_r:metadata_file:s0 tclass=dir permissive=0
        07-08 15:08:21.207   853   853 I auditd  : type=1400 audit(0.0:89): avc: denied { search } for comm="e2fsck" name="/" dev="tmpfs" ino=1 scontext=u:r:fsck:s0 tcontext=u:object_r:mirror_data_file:s0 tclass=dir permissive=0

Bug: 193137337
Test: treehugger
Change-Id: Ib050463f7fa6ea453795c933ff388d3594bb7c23
2021-07-13 10:17:30 -07:00

73 lines
2.3 KiB
Text

# Any fsck program run by init
type fsck, domain;
type fsck_exec, system_file_type, exec_type, file_type;
# /dev/__null__ created by init prior to policy load,
# open fd inherited by fsck.
allow fsck tmpfs:chr_file { read write ioctl };
# Inherit and use pty created by android_fork_execvp_ext().
allow fsck devpts:chr_file { read write ioctl getattr };
# Allow stdin/out back to vold
allow fsck vold:fd use;
allow fsck vold:fifo_file { read write getattr };
# Run fsck on certain block devices
allow fsck userdata_block_device:blk_file rw_file_perms;
allow fsck cache_block_device:blk_file rw_file_perms;
allow fsck dm_device:blk_file rw_file_perms;
userdebug_or_eng(`
allow fsck system_block_device:blk_file rw_file_perms;
')
# e2fsck performs a comprehensive search of /proc/mounts to check whether the
# checked filesystem is currently mounted.
allow fsck metadata_file:dir getattr;
allow fsck block_device:dir search;
allow fsck mirror_data_file:dir search;
# For the block devices where we have ioctl access,
# allow at a minimum the following common fsck ioctls.
allowxperm fsck dev_type:blk_file ioctl {
BLKDISCARDZEROES
BLKROGET
};
# To determine if it is safe to run fsck on a filesystem, e2fsck
# must first determine if the filesystem is mounted. To do that,
# e2fsck scans through /proc/mounts and collects all the mounted
# block devices. With that information, it runs stat() on each block
# device, comparing the major and minor numbers to the filesystem
# passed in on the command line. If there is a match, then the filesystem
# is currently mounted and running fsck is dangerous.
# Allow stat access to all block devices so that fsck can compare
# major/minor values.
allow fsck dev_type:blk_file getattr;
allow fsck {
proc_mounts
proc_swaps
}:file r_file_perms;
allow fsck rootfs:dir r_dir_perms;
###
### neverallow rules
###
# fsck should never be run on these block devices
neverallow fsck {
boot_block_device
frp_block_device
recovery_block_device
root_block_device
swap_block_device
system_block_device
userdebug_or_eng(`-system_block_device')
vold_device
}:blk_file no_rw_file_perms;
# Only allow entry from init or vold via fsck binaries
neverallow { domain -init -vold } fsck:process transition;
neverallow * fsck:process dyntransition;
neverallow fsck { file_type fs_type -fsck_exec }:file entrypoint;