I am unable to make sense of this message which I get on my android application. Any experts in the house ?
type=1400 audit(0.0:2233): avc: denied { create } for name="access_control.new_commit.cv" scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:object_r:fuse:s0:c512,c768 tclass=fifo_file permissive=0
The given SELinux violation:
type=1400 audit(0.0:2233): avc: denied { create } for name="access_control.new_commit.cv" scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:object_r:fuse:s0:c512,c768 tclass=fifo_file permissive=0
Below I'll try to give explanation of important parts of above violation:
denied { create } : Operation Permission State : The denied permission that was requested / executed. In this case, it is a create operation. SELinux denying permission to execute create dir/file operation.
name="access_control.new_commit.cv": Target name : The name of the target (in this case, the file/dir name) which your application, probably, trying to create.
scontext=u:r:untrusted_app:s0 : Source Context : The Source Context for this security violation. This indicates which domain/process is trying to execute create functionality. Here, untrusted_app applications are those which are launched by zygote
tcontext=u:object_r:fuse:s0 : Target Context : The security context of the target resource (in this case the file). Here, the source tried to create file in Fuse file system which has been denied.
tclass=fifo_file : Target Class : The class of the target.
In one sentence, SELinux denied the permission to untrusted_app to create the access_control.new_commit.cv file in fuse.
From Google source, check SEPolicy file untrusted_app.te how the permission has been denied.
NB: If you any suggestion with the answer, let me know.
According to Validating SELinux | Android Open Source Project, for message:
type=1400 audit(0.0:2233): avc: denied { create } for name="access_control.new_commit.cv" scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:object_r:fuse:s0:c512,c768 tclass=fifo_file permissive=0
the key info is:
Action: createActor=scontext=source context: untrusted_appObject=tcontext=target context: fuse
object_r=object read ?Result=tclass=target class: fifo_file=FIFO filepermissive=permissive mode: 0 -> NOT permissive mode
translated to human readable sentence:
untrusted_app want to create a fifo_file for fuse
(But enforce mode of Android SELinux STOP it for no permission, so you see above logcat log info)
I could add that running audit2allow on the error message will give you a suggestion on how to update the untrusted_app.te file.
Dump dmesg to text file:
dmesg > /sdcard/dmesg.txt
cat dmesg.txt | grep avc | audit2allow
will give you the following result in this case:
#============= untrusted_app ==============
allow untrusted_app fuse:fifo_file create;
Add this line to untrusted_app.te and rebuild the Android kernel!
