337f56467b
system/sepolicy commit ffa2b61330
introduced the runas_app SELinux domain, which changed how we perform
debugging of Android applications. This broke Android Studio's lldb.
From bugreport:
Debugging an app containing native code using ndk-gdb or Android
Studio's lldb currently fails. There is an selinux error in logcat
about a sigchld denial. Studio can still debug Java-only apps.
In Android Studio, starting the debugger on an app with native
code produces this selinux denial:
01-30 06:58:02.089 13449 13449 W lldb-server: type=1400 audit(0.0:831): avc: denied { sigchld } for scontext=u:r:untrusted_app_27:s0:c167,c256,c512,c768 tcontext=u:r:runas_app:s0:c167,c256,c512,c768 tclass=process permissive=0 app=com.android.ndktestapp
With "set enforce 0", I also see a sigstop denial:
01-30 07:31:12.209 15672 15672 I lldb-server: type=1400 audit(0.0:1290): avc: denied { sigstop } for scontext=u:r:runas_app:s0:c167,c256,c512,c768 tcontext=u:r:untrusted_app_27:s0:c167,c256,c512,c768 tclass=process permissive=1 app=com.android.ndktestapp
In gdb-server.log, Studio reports this error while trying to start lldb-server:
1548831482.091491938 GDBRemoteCommunicationServerLLGS::Handle_vAttach attempting to attach to pid 13379
1548831482.091519117 GDBRemoteCommunicationServerLLGS::AttachToProcess pid 13379
1548831482.092242956 GDBRemoteCommunicationServerLLGS::Handle_vAttach failed to attach to pid 13379: Permission denied
Using ndk-gdb (e.g. on the NdkGdbSample) produces the same sort
of selinux denial:
01-30 07:11:26.742 13926 13926 W arm64-gdbserver: type=1400 audit(0.0:833): avc: denied { sigchld } for scontext=u:r:untrusted_app_27:s0:c166,c256,c512,c768 tcontext=u:r:runas_app:s0:c166,c256,c512,c768 tclass=process permissive=0 app=com.android.developer.ndkgdbsample
If I use "setenforce 0", I see more denials logged (signal and
sigstop):
01-30 07:30:23.346 15478 15478 I arm64-gdbserver: type=1400 audit(0.0:1287): avc: denied { signal } for scontext=u:r:runas_app:s0:c166,c256,c512,c768 tcontext=u:r:untrusted_app_27:s0:c166,c256,c512,c768 tclass=process permissive=1 app=com.android.developer.ndkgdbsample
01-30 07:30:23.349 15478 15478 I arm64-gdbserver: type=1400 audit(0.0:1288): avc: denied { sigstop } for scontext=u:r:runas_app:s0:c166,c256,c512,c768 tcontext=u:r:untrusted_app_27:s0:c166,c256,c512,c768 tclass=process permissive=1 app=com.android.developer.ndkgdbsample
ndk-gdb times out and prints an error:
rprichard@cashew:/x/ndk/ndk/samples/NdkGdbSample$ /x/android-ndk-r19/ndk-gdb --launch
Redirecting gdbserver output to /tmp/gdbclient.log
...
Error: unable to connect to device.
Remote communication error. Target disconnected.: Connection reset by peer.
gdbclient.log shows that gdbserver hasn't started listening to its Unix socket yet:
rprichard@cashew:/x/ndk/ndk/samples/NdkGdbSample$ cat /tmp/gdbclient.log
Attached; pid = 14232
Normal output looks like this:
rprichard@cashew:/x/ndk/ndk/samples/NdkGdbSample$ cat /tmp/gdbclient.log
Attached; pid = 27799
Listening on Unix domain socket '/data/data/com.android.developer.ndkgdbsample/debug_socket'
Remote debugging from host 127.0.0.0
Test: compiles and builds
Bug: 123612207
Change-Id: Ia9a711cc54cc044c0817a7c17eb4506015adb393
178 lines
8 KiB
Text
178 lines
8 KiB
Text
###
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### Untrusted_app_all.
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###
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### This file defines the rules shared by all untrusted app domains except
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### ephemeral_app for instant apps.
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### Apps are labeled based on mac_permissions.xml (maps signer and
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### optionally package name to seinfo value) and seapp_contexts (maps UID
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### and optionally seinfo value to domain for process and type for data
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### directory). The untrusted_app_all attribute is assigned to all default
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### seapp_contexts for any app with UID between APP_AID (10000)
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### and AID_ISOLATED_START (99000) if the app has no specific seinfo
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### value as determined from mac_permissions.xml. In current AOSP, this
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### attribute is assigned to all non-system apps as well as to any system apps
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### that are not signed by the platform key. To move
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### a system app into a specific domain, add a signer entry for it to
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### mac_permissions.xml and assign it one of the pre-existing seinfo values
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### or define and use a new seinfo value in both mac_permissions.xml and
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### seapp_contexts.
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###
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### Note that rules that should apply to all untrusted apps must be in app.te or also
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### added to ephemeral_app.te.
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# Some apps ship with shared libraries and binaries that they write out
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# to their sandbox directory and then execute.
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allow untrusted_app_all privapp_data_file:file { r_file_perms execute };
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allow untrusted_app_all app_data_file:file { r_file_perms execute };
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# Follow priv-app symlinks. This is used for dynamite functionality.
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allow untrusted_app_all privapp_data_file:lnk_file r_file_perms;
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# Allow handling of less common filesystem objects
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allow untrusted_app_all app_data_file:{ lnk_file sock_file fifo_file } create_file_perms;
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# Allow loading and deleting executable shared libraries
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# within an application home directory. Such shared libraries would be
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# created by things like renderscript or via other mechanisms.
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allow untrusted_app_all app_exec_data_file:file { r_file_perms execute unlink };
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# ASEC
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allow untrusted_app_all asec_apk_file:file r_file_perms;
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allow untrusted_app_all asec_apk_file:dir r_dir_perms;
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# Execute libs in asec containers.
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allow untrusted_app_all asec_public_file:file { execute };
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# Used by Finsky / Android "Verify Apps" functionality when
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# running "adb install foo.apk".
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# TODO: Long term, we don't want apps probing into shell data files.
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# Figure out a way to remove these rules.
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allow untrusted_app_all shell_data_file:file r_file_perms;
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allow untrusted_app_all shell_data_file:dir r_dir_perms;
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# Allow traceur to pass file descriptors through a content provider to untrusted apps
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# for the purpose of sharing files through e.g. gmail
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allow untrusted_app_all trace_data_file:file { getattr read };
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# untrusted apps should not be able to open trace data files, they should depend
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# upon traceur to pass a file descriptor
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neverallow untrusted_app_all trace_data_file:dir *;
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neverallow untrusted_app_all trace_data_file:file { no_w_file_perms open };
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# Allow to read staged apks.
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allow untrusted_app_all { apk_tmp_file apk_private_tmp_file }:file {read getattr};
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# Read and write system app data files passed over Binder.
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# Motivating case was /data/data/com.android.settings/cache/*.jpg for
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# cropping or taking user photos.
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allow untrusted_app_all system_app_data_file:file { read write getattr };
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#
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# Rules migrated from old app domains coalesced into untrusted_app.
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# This includes what used to be media_app, shared_app, and release_app.
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#
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# Access to /data/media.
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allow untrusted_app_all media_rw_data_file:dir create_dir_perms;
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allow untrusted_app_all media_rw_data_file:file create_file_perms;
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# Traverse into /mnt/media_rw for bypassing FUSE daemon
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# TODO: narrow this to just MediaProvider
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allow untrusted_app_all mnt_media_rw_file:dir search;
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# allow cts to query all services
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allow untrusted_app_all servicemanager:service_manager list;
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allow untrusted_app_all audioserver_service:service_manager find;
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allow untrusted_app_all cameraserver_service:service_manager find;
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allow untrusted_app_all drmserver_service:service_manager find;
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allow untrusted_app_all mediaserver_service:service_manager find;
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allow untrusted_app_all mediaextractor_service:service_manager find;
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allow untrusted_app_all mediacodec_service:service_manager find;
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allow untrusted_app_all mediametrics_service:service_manager find;
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allow untrusted_app_all mediadrmserver_service:service_manager find;
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allow untrusted_app_all nfc_service:service_manager find;
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allow untrusted_app_all radio_service:service_manager find;
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allow untrusted_app_all app_api_service:service_manager find;
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allow untrusted_app_all vr_manager_service:service_manager find;
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# Allow GMS core to access perfprofd output, which is stored
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# in /data/misc/perfprofd/. GMS core will need to list all
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# data stored in that directory to process them one by one.
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userdebug_or_eng(`
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allow untrusted_app_all perfprofd_data_file:file r_file_perms;
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allow untrusted_app_all perfprofd_data_file:dir r_dir_perms;
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')
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# gdbserver for ndk-gdb ptrace attaches to app process.
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allow untrusted_app_all self:process ptrace;
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# Android Studio Instant Run has the application connect to a
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# runas_app socket listening in the abstract namespace.
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# https://developer.android.com/studio/run/
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# b/123297648
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allow untrusted_app_all runas_app:unix_stream_socket connectto;
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# Untrusted apps need to be able to send a SIGCHLD to runas_app
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# when running under a debugger (b/123612207)
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allow untrusted_app_all runas_app:process sigchld;
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# Cts: HwRngTest
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allow untrusted_app_all sysfs_hwrandom:dir search;
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allow untrusted_app_all sysfs_hwrandom:file r_file_perms;
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# Allow apps to view preloaded media content
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allow untrusted_app_all preloads_media_file:dir r_dir_perms;
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allow untrusted_app_all preloads_media_file:file r_file_perms;
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allow untrusted_app_all preloads_data_file:dir search;
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# Allow untrusted apps read / execute access to /vendor/app for there can
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# be pre-installed vendor apps that package a library within themselves.
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# TODO (b/37784178) Consider creating a special type for /vendor/app installed
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# apps.
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allow untrusted_app_all vendor_app_file:dir { open getattr read search };
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allow untrusted_app_all vendor_app_file:file { r_file_perms execute };
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allow untrusted_app_all vendor_app_file:lnk_file { open getattr read };
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# Write app-specific trace data to the Perfetto traced damon. This requires
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# connecting to its producer socket and obtaining a (per-process) tmpfs fd.
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allow untrusted_app_all traced:fd use;
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allow untrusted_app_all traced_tmpfs:file { read write getattr map };
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unix_socket_connect(untrusted_app_all, traced_producer, traced)
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# Allow heap profiling if the app opts in by being marked
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# profileable/debuggable.
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can_profile_heap(untrusted_app_all)
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# allow untrusted apps to use UDP sockets provided by the system server but not
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# modify them other than to connect
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allow untrusted_app_all system_server:udp_socket {
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connect getattr read recvfrom sendto write getopt setopt };
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# Allow the renderscript compiler to be run.
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domain_auto_trans(untrusted_app_all, rs_exec, rs)
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# This is allowed for targetSdkVersion <= 25 but disallowed on newer versions.
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dontaudit untrusted_app_all net_dns_prop:file read;
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# These have been disallowed since Android O.
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# For P, we assume that apps are safely handling the denial.
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dontaudit untrusted_app_all proc_stat:file read;
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dontaudit untrusted_app_all proc_vmstat:file read;
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dontaudit untrusted_app_all proc_uptime:file read;
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# Allow the allocation and use of ptys
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# Used by: https://play.google.com/store/apps/details?id=jackpal.androidterm
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create_pty(untrusted_app_all)
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# Attempts to write to system_data_file is generally a sign
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# that apps are attempting to access encrypted storage before
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# the ACTION_USER_UNLOCKED intent is delivered. Suppress this
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# denial to prevent third party apps from spamming the logs.
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dontaudit untrusted_app_all system_data_file:dir write;
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# Allow access to kcov via its ioctl interface for coverage
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# guided kernel fuzzing.
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userdebug_or_eng(`
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allow untrusted_app_all debugfs_kcov:file rw_file_perms;
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allowxperm untrusted_app_all debugfs_kcov:file ioctl { KCOV_INIT_TRACE KCOV_ENABLE KCOV_DISABLE };
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')
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