platform_system_sepolicy/private/coredomain.te
Nick Kralevich 0eb0a16fbd bless app created renderscript files
When an app uses renderscript to compile a Script instance,
renderscript compiles and links the script using /system/bin/bcc and
/system/bin/ld.mc, then places the resulting shared library into the
application's code_cache directory. The application then dlopen()s the
resulting shared library.

Currently, this executable code is writable to the application. This
violates the W^X property (https://en.wikipedia.org/wiki/W%5EX), which
requires any executable code be immutable.

This change introduces a new label "rs_data_file". Files created by
/system/bin/bcc and /system/bin/ld.mc in the application's home
directory assume this label. This allows us to differentiate in
security policy between app created files, and files created by
renderscript on behalf of the application.

Apps are allowed to delete these files, but cannot create or write these
files. This is enforced through a neverallow compile time assertion.

Several exceptions are added to Treble neverallow assertions to support
this functionality. However, because renderscript was previously invoked
from an application context, this is not a Treble separation regression.

This change is needed to support blocking dlopen() for non-renderscript
/data/data files, which will be submitted in a followup change.

Bug: 112357170
Test: cts-tradefed run cts -m CtsRenderscriptTestCases
Change-Id: Ie38bbd94d26db8a418c2a049c24500a5463698a3
2018-12-12 13:20:22 -08:00

184 lines
3.8 KiB
Text

get_prop(coredomain, pm_prop)
get_prop(coredomain, exported_pm_prop)
full_treble_only(`
neverallow {
coredomain
# for chowning
-init
# generic access to sysfs_type
-ueventd
-vold
} sysfs_leds:file *;
')
# On TREBLE devices, a limited set of files in /vendor are accessible to
# only a few whitelisted coredomains to keep system/vendor separation.
full_treble_only(`
# Limit access to /vendor/app
neverallow {
coredomain
-appdomain
-dex2oat
-idmap
-init
-installd
userdebug_or_eng(`-perfprofd')
userdebug_or_eng(`-heapprofd')
-postinstall_dexopt
-rs # spawned by appdomain, so carryover the exception above
-system_server
} vendor_app_file:dir { open read getattr search };
')
full_treble_only(`
neverallow {
coredomain
-appdomain
-dex2oat
-idmap
-init
-installd
userdebug_or_eng(`-perfprofd')
userdebug_or_eng(`-heapprofd')
-postinstall_dexopt
-rs # spawned by appdomain, so carryover the exception above
-system_server
-mediaserver
} vendor_app_file:file r_file_perms;
')
full_treble_only(`
# Limit access to /vendor/overlay
neverallow {
coredomain
-appdomain
-idmap
-init
-installd
-rs # spawned by appdomain, so carryover the exception above
-system_server
-webview_zygote
-zygote
userdebug_or_eng(`-heapprofd')
} vendor_overlay_file:dir { getattr open read search };
')
full_treble_only(`
neverallow {
coredomain
-appdomain
-idmap
-init
-installd
-rs # spawned by appdomain, so carryover the exception above
-system_server
-webview_zygote
-zygote
userdebug_or_eng(`-heapprofd')
} vendor_overlay_file:file r_file_perms;
')
# Core domains are not permitted to use kernel interfaces which are not
# explicitly labeled.
# TODO(b/65643247): Apply these neverallow rules to all coredomain.
full_treble_only(`
# /proc
neverallow {
coredomain
-vold
} proc:file no_rw_file_perms;
# /sys
neverallow {
coredomain
-init
-ueventd
-vold
} sysfs:file no_rw_file_perms;
# /dev
neverallow {
coredomain
-fsck
-init
-ueventd
} device:{ blk_file file } no_rw_file_perms;
# debugfs
neverallow {
coredomain
-dumpstate
-init
-system_server
} debugfs:file no_rw_file_perms;
# tracefs
neverallow {
coredomain
-atrace
-dumpstate
-init
userdebug_or_eng(`-perfprofd')
-traced_probes
-shell
-traceur_app
} debugfs_tracing:file no_rw_file_perms;
# inotifyfs
neverallow {
coredomain
-init
} inotify:file no_rw_file_perms;
# pstorefs
neverallow {
coredomain
-bootstat
-charger
-dumpstate
-healthd
userdebug_or_eng(`-incidentd')
-init
-logd
-logpersist
-recovery_persist
-recovery_refresh
-shell
-system_server
} pstorefs:file no_rw_file_perms;
# configfs
neverallow {
coredomain
-init
-system_server
} configfs:file no_rw_file_perms;
# functionfs
neverallow {
coredomain
-adbd
-init
-mediaprovider
-system_server
} functionfs:file no_rw_file_perms;
# usbfs and binfmt_miscfs
neverallow {
coredomain
-init
}{ usbfs binfmt_miscfs }:file no_rw_file_perms;
')
# Following /dev nodes must not be directly accessed by coredomain, but should
# instead be wrapped by HALs.
neverallow coredomain {
iio_device
radio_device
# TODO(b/120243891): HAL permission to tee_device is included into coredomain
# on non-Treble devices.
full_treble_only(`tee_device')
}:chr_file { open read append write ioctl };