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
17 lines
653 B
Text
17 lines
653 B
Text
typeattribute runas_app coredomain;
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app_domain(runas_app)
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untrusted_app_domain(runas_app)
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net_domain(runas_app)
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bluetooth_domain(runas_app)
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# The ability to call exec() on files in the apps home directories
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# when using run-as on a debuggable app. Used to run lldb/ndk-gdb/simpleperf,
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# which are copied to the apps home directories.
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allow runas_app app_data_file:file execute_no_trans;
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# Allow lldb/ndk-gdb/simpleperf to read maps of debuggable app processes.
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r_dir_file(runas_app, untrusted_app_all)
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# Allow lldb/ndk-gdb/simpleperf to ptrace attach to debuggable app processes.
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allow runas_app untrusted_app_all:process { ptrace signal sigstop };
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