03ce512072
Don't allow writes to /system from unconfined domains. /system is always mounted read-only, and no process should ever need to write there. Allow recovery to write to /system. This is needed to apply OTA images. Change-Id: I11aa8bd0c3b7f53ebe83806a0547ab8d5f25f3c9
256 lines
9.7 KiB
Text
256 lines
9.7 KiB
Text
# Rules for all domains.
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# Allow reaping by init.
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allow domain init:process sigchld;
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# Read access to properties mapping.
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allow domain kernel:fd use;
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allow domain tmpfs:file { read getattr };
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# Search /storage/emulated tmpfs mount.
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allow domain tmpfs:dir r_dir_perms;
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# Intra-domain accesses.
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allow domain self:process ~{ execmem execstack execheap ptrace setexec setfscreate setcurrent setkeycreate setsockcreate };
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allow domain self:fd use;
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allow domain self:dir r_dir_perms;
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allow domain self:lnk_file r_file_perms;
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allow domain self:{ fifo_file file } rw_file_perms;
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allow domain self:unix_dgram_socket { create_socket_perms sendto };
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allow domain self:unix_stream_socket { create_stream_socket_perms connectto };
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# Inherit or receive open files from others.
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allow domain init:fd use;
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allow domain system_server:fd use;
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# Connect to adbd and use a socket transferred from it.
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# This is used for e.g. adb backup/restore.
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allow domain adbd:unix_stream_socket connectto;
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allow domain adbd:fd use;
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allow domain adbd:unix_stream_socket { getattr getopt read write shutdown };
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userdebug_or_eng(`
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# Same as adbd rules above, except allow su to do the same thing
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allow domain su:unix_stream_socket connectto;
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allow domain su:fd use;
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allow domain su:unix_stream_socket { getattr getopt read write shutdown };
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binder_call(domain, su)
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# Running something like "pm dump com.android.bluetooth" requires
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# fifo writes
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allow domain su:fifo_file { write getattr };
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# allow "gdbserver --attach" to work for su.
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allow domain su:process sigchld;
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')
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###
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### Talk to debuggerd.
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###
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allow domain debuggerd:process sigchld;
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allow domain debuggerd:unix_stream_socket connectto;
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# Root fs.
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allow domain rootfs:dir r_dir_perms;
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allow domain rootfs:file r_file_perms;
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allow domain rootfs:lnk_file r_file_perms;
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# Device accesses.
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allow domain device:dir search;
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allow domain dev_type:lnk_file r_file_perms;
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allow domain devpts:dir search;
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allow domain device:file read;
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allow domain socket_device:dir r_dir_perms;
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allow domain owntty_device:chr_file rw_file_perms;
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allow domain null_device:chr_file rw_file_perms;
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allow domain zero_device:chr_file rw_file_perms;
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allow domain ashmem_device:chr_file rw_file_perms;
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allow domain binder_device:chr_file rw_file_perms;
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allow domain ptmx_device:chr_file rw_file_perms;
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allow domain log_device:dir search;
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allow domain log_device:chr_file rw_file_perms;
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allow domain alarm_device:chr_file r_file_perms;
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allow domain urandom_device:chr_file rw_file_perms;
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allow domain random_device:chr_file rw_file_perms;
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allow domain properties_device:file r_file_perms;
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# logd access
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write_logd(domain)
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# Filesystem accesses.
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allow domain fs_type:filesystem getattr;
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allow domain fs_type:dir getattr;
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# System file accesses.
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allow domain system_file:dir r_dir_perms;
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allow domain system_file:file r_file_perms;
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allow domain system_file:file execute;
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allow domain system_file:lnk_file r_file_perms;
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# Read files already opened under /data.
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allow domain system_data_file:dir { search getattr };
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allow domain system_data_file:file { getattr read };
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allow domain system_data_file:lnk_file r_file_perms;
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# Read apk files under /data/app.
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allow domain apk_data_file:dir { getattr search };
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allow domain apk_data_file:file r_file_perms;
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# Read /data/dalvik-cache.
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allow domain dalvikcache_data_file:dir { search getattr };
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allow domain dalvikcache_data_file:file r_file_perms;
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allow domain dalvikcache_profiles_data_file:dir { search getattr };
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allow domain dalvikcache_profiles_data_file:file r_file_perms;
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# Read already opened /cache files.
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allow domain cache_file:dir r_dir_perms;
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allow domain cache_file:file { getattr read };
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allow domain cache_file:lnk_file r_file_perms;
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# Read timezone related information
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r_dir_file(domain, zoneinfo_data_file)
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# For /acct/uid/*/tasks.
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allow domain cgroup:dir { search write };
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allow domain cgroup:file w_file_perms;
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#Allow access to ion memory allocation device
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allow domain ion_device:chr_file rw_file_perms;
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# Read access to pseudo filesystems.
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r_dir_file(domain, proc)
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r_dir_file(domain, sysfs)
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r_dir_file(domain, sysfs_devices_system_cpu)
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r_dir_file(domain, inotify)
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r_dir_file(domain, cgroup)
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r_dir_file(domain, proc_net)
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# debugfs access
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allow domain debugfs:dir r_dir_perms;
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allow domain debugfs:file w_file_perms;
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# Get SELinux enforcing status.
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selinux_getenforce(domain)
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# /data/security files
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allow domain security_file:dir { search getattr };
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allow domain security_file:file getattr;
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allow domain security_file:lnk_file r_file_perms;
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# World readable asec image contents
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allow domain asec_public_file:file r_file_perms;
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allow domain { asec_public_file asec_apk_file }:dir r_dir_perms;
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######## Backwards compatibility - Unlabeled files ############
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# Revert to DAC rules when looking at unlabeled files. Over time, the number
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# of unlabeled files should decrease.
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# TODO: delete these rules in the future.
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#
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allow domain unlabeled:notdevfile_class_set { create_file_perms relabelfrom };
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allow domain unlabeled:dir { create_dir_perms relabelfrom };
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auditallow { domain -init -installd } unlabeled:notdevfile_class_set { create_file_perms relabelfrom };
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auditallow { domain -init -kernel -installd } unlabeled:dir { create_dir_perms relabelfrom };
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auditallow kernel unlabeled:dir ~search;
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auditallow installd unlabeled:dir ~{ getattr search relabelfrom };
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auditallow installd unlabeled:notdevfile_class_set ~{ getattr relabelfrom };
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###
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### neverallow rules
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###
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# Limit ability to ptrace or read sensitive /proc/pid files of processes
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# with other UIDs to these whitelisted domains.
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neverallow { domain -debuggerd -vold -dumpstate -system_server } self:capability sys_ptrace;
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# Limit device node creation and raw I/O to these whitelisted domains.
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neverallow { domain -kernel -init -recovery -ueventd -watchdogd -healthd -vold -uncrypt } self:capability { sys_rawio mknod };
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# No process can map low memory (< CONFIG_LSM_MMAP_MIN_ADDR).
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neverallow domain self:memprotect mmap_zero;
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# No domain needs mac_override as it is unused by SELinux.
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neverallow domain self:capability2 mac_override;
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# Only recovery needs mac_admin to set contexts not defined in current policy.
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neverallow { domain -recovery } self:capability2 mac_admin;
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# Only init should be able to load SELinux policies.
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# The first load technically occurs while still in the kernel domain,
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# but this does not trigger a denial since there is no policy yet.
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# Policy reload requires allowing this to the init domain.
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neverallow { domain -init } kernel:security load_policy;
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# Only init prior to switching context should be able to set enforcing mode.
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# init starts in kernel domain and switches to init domain via setcon in
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# the init.rc, so the setenforce occurs while still in kernel. After
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# switching domains, there is never any need to setenforce again by init.
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neverallow domain kernel:security setenforce;
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neverallow { domain -kernel } kernel:security setcheckreqprot;
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# No booleans in AOSP policy, so no need to ever set them.
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neverallow domain kernel:security setbool;
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# Adjusting the AVC cache threshold.
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# Not presently allowed to anything in policy, but possibly something
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# that could be set from init.rc.
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neverallow { domain -init } kernel:security setsecparam;
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# Only init, ueventd and system_server should be able to access HW RNG
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neverallow { domain -init -system_server -ueventd -unconfineddomain } hw_random_device:chr_file *;
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# Ensure that all entrypoint executables are in exec_type.
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neverallow domain { file_type -exec_type }:file entrypoint;
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# Ensure that nothing in userspace can access /dev/mem or /dev/kmem
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neverallow { domain -kernel -ueventd -init } kmem_device:chr_file *;
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neverallow domain kmem_device:chr_file ~{ create relabelto unlink setattr };
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# Only init should be able to configure kernel usermodehelpers or
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# security-sensitive proc settings.
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neverallow { domain -init } usermodehelper:file { append write };
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neverallow { domain -init } proc_security:file { append write };
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# No domain should be allowed to ptrace init.
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neverallow domain init:process ptrace;
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# Init can't receive binder calls. If this neverallow rule is being
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# triggered, it's probably due to a service with no SELinux domain.
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neverallow domain init:binder call;
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# Don't allow raw read/write/open access to block_device
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# Rather force a relabel to a more specific type
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neverallow { domain -kernel -init -recovery -vold -uncrypt } block_device:blk_file { open read write };
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# Don't allow raw read/write/open access to generic devices.
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# Rather force a relabel to a more specific type.
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# ueventd is exempt from this, as its managing these devices.
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neverallow { domain -unconfineddomain -ueventd } device:chr_file { open read write };
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# Limit what domains can mount filesystems or change their mount flags.
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# sdcard_type / vfat is exempt as a larger set of domains need
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# this capability, including device-specific domains.
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neverallow { domain -kernel -init -recovery -vold -zygote } { fs_type -sdcard_type }:filesystem { mount remount relabelfrom relabelto };
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#
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# Assert that, to the extent possible, we're not loading executable content from
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# outside the /system partition except for a few whitelisted domains.
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#
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neverallow {
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domain
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-appdomain
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-dumpstate
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-shelldomain
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userdebug_or_eng(`-su')
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-system_server
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-zygote
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} { file_type -system_file -exec_type }:file execute;
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# Only the init property service should write to /data/property.
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neverallow { domain -init } property_data_file:dir { create setattr relabelfrom rename write add_name remove_name rmdir };
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neverallow { domain -init } property_data_file:file { create setattr relabelfrom write append unlink link rename };
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# Only recovery should be doing writes to /system
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neverallow { domain -recovery } { system_file exec_type }:dir_file_class_set
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{ create write setattr relabelfrom relabelto append unlink link rename };
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