This patch adds the necessary rules to support the existing usage of
perf_event_open by the system partition, which almost exclusively
concerns the simpleperf profiler. A new domain is introduced for some
(but not all) executions of the system image simpleperf. The following
configurations are supported:
* shell -> shell process (no domain transition)
* shell -> debuggable app (through shell -> runas -> runas_app)
* shell -> profileable app (through shell -> simpleperf_app_runner ->
untrusted_app -> simpleperf)
* debuggable/profile app -> self (through untrusted_app -> simpleperf)
simpleperf_app_runner still enters the untrusted_app domain immediately
before exec to properly inherit the categories related to MLS. My
understanding is that a direct transition would require modifying
external/selinux and seapp_contexts as with "fromRunAs", which seems
unnecessarily complex for this case.
runas_app can still run side-loaded binaries and use perf_event_open,
but it checks that the target app is exactly "debuggable"
(profileability is insufficient).
system-wide profiling is effectively constrained to "su" on debug
builds.
See go/perf-event-open-security for a more detailed explanation of the
scenarios covered here.
Tested: "atest CtsSimpleperfTestCases" on crosshatch-user/userdebug
Tested: manual simpleperf invocations on crosshatch-userdebug
Bug: 137092007
Change-Id: I2100929bae6d81f336f72eff4235fd5a78b94066
The open, audit_access, execmod, and watch* permissions
are all defined in the COMMON_FILE_PERMS in the kernel
classmap and inherited by all the file-related classes;
we can do the same in the policy by putting them into the
common file declaration.
refpolicy recently similarly reorganized its definitions and added the
watch* permissions to common file, see:
e5dbe75276c656b97a283952ecb4dd
Adding new permissions to the end of the existing classes was only
required for kernels that predate the dynamic class/perm mapping
support (< v2.6.33).
Test: policy still builds
Change-Id: I44a2c3a94c21ed23410b6f807af7f1179e2c1747
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
This property essentially implements
PowerManager.isRebootingUserspaceSupported[0] public API, hence apps
should be able to read it.
[0]: 73cab34d9f:core/java/android/os/PowerManager.java;l=1397
Test: m checkbuild
Test: atest CtsUserspaceRebootHostSideTestCases
Test: adb shell getprop ro.init.userspace_reboot.is_supported
Bug: 135984674
Change-Id: I09cab09735760529de81eb6d5306f052ee408a6e
The binder_cache_system_server_prop context allows any user to read the
property but only the system_server to write it. The only property with
this context is currently binder.cache_key.has_system_feature but users
will be added.
Bug: 140788621
Test: this was tested on an image with a binder cache implementation. No
permission issues were found. The implementation is not part of the current
commit.
Change-Id: I4c7c3ddf809ed947944408ffbbfc469d761a6043
This patch allows us to write SELinux policies for the
perf_event_open() syscall LSM hooks added to the kernel in the following
commit:
da97e18458
Bug: 137092007
Change-Id: I0005759eb7a487faebe94a4653e3865343eb441e
