9b2e0cbeea
In kernel 4.7, the capability and capability2 classes were split apart
from cap_userns and cap2_userns (see kernel commit
8e4ff6f228e4722cac74db716e308d1da33d744f). Since then, Android cannot be
run in a container with SELinux in enforcing mode.
This change applies the existing capability rules to user namespaces as
well as the root namespace so that Android running in a container
behaves the same on pre- and post-4.7 kernels.
This is essentially:
1. New global_capability_class_set and global_capability2_class_set
that match capability+cap_userns and capability2+cap2_userns,
respectively.
2. s/self:capability/self:global_capability_class_set/g
3. s/self:capability2/self:global_capability2_class_set/g
4. Add cap_userns and cap2_userns to the existing capability_class_set
so that it covers all capabilities. This set was used by several
neverallow and dontaudit rules, and I confirmed that the new
classes are still appropriate.
Test: diff new policy against old and confirm that all new rules add
only cap_userns or cap2_userns;
Boot ARC++ on a device with the 4.12 kernel.
Bug: crbug.com/754831
Change-Id: I4007eb3a2ecd01b062c4c78d9afee71c530df95f
104 lines
3.9 KiB
Text
104 lines
3.9 KiB
Text
# Life begins with the kernel.
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type kernel, domain, mlstrustedsubject;
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allow kernel self:global_capability_class_set sys_nice;
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# Root fs.
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r_dir_file(kernel, rootfs)
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allow kernel proc_cmdline:file r_file_perms;
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# Get SELinux enforcing status.
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allow kernel selinuxfs:dir r_dir_perms;
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allow kernel selinuxfs:file r_file_perms;
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# Get file contexts during first stage
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allow kernel file_contexts_file:file r_file_perms;
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# Allow init relabel itself.
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allow kernel rootfs:file relabelfrom;
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allow kernel init_exec:file relabelto;
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# TODO: investigate why we need this.
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allow kernel init:process share;
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# cgroup filesystem initialization prior to setting the cgroup root directory label.
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allow kernel unlabeled:dir search;
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# Mount usbfs.
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allow kernel usbfs:filesystem mount;
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allow kernel usbfs:dir search;
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# Initial setenforce by init prior to switching to init domain.
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# We use dontaudit instead of allow to prevent a kernel spawned userspace
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# process from turning off SELinux once enabled.
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dontaudit kernel self:security setenforce;
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# Write to /proc/1/oom_adj prior to switching to init domain.
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allow kernel self:global_capability_class_set sys_resource;
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# Init reboot before switching selinux domains under certain error
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# conditions. Allow it.
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# As part of rebooting, init writes "u" to /proc/sysrq-trigger to
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# remount filesystems read-only. /data is not mounted at this point,
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# so we could ignore this. For now, we allow it.
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allow kernel self:global_capability_class_set sys_boot;
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allow kernel proc_sysrq:file w_file_perms;
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# Allow writing to /dev/kmsg which was created prior to loading policy.
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allow kernel tmpfs:chr_file write;
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# Set checkreqprot by init.rc prior to switching to init domain.
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allow kernel selinuxfs:file write;
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allow kernel self:security setcheckreqprot;
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# kernel thread "loop0", used by the loop block device, for ASECs (b/17158723)
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allow kernel sdcard_type:file { read write };
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# f_mtp driver accesses files from kernel context.
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allow kernel mediaprovider:fd use;
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# Allow the kernel to read OBB files from app directories. (b/17428116)
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# Kernel thread "loop0" reads a vold supplied file descriptor.
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# Fixes CTS tests:
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# * android.os.storage.cts.StorageManagerTest#testMountAndUnmountObbNormal
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# * android.os.storage.cts.StorageManagerTest#testMountAndUnmountTwoObbs
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allow kernel vold:fd use;
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allow kernel app_data_file:file read;
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allow kernel asec_image_file:file read;
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# Allow reading loop device in update_engine_unittests. (b/28319454)
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userdebug_or_eng(`
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allow kernel update_engine_data_file:file read;
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allow kernel nativetest_data_file:file read;
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')
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# Access to /data/media.
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# This should be removed if sdcardfs is modified to alter the secontext for its
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# accesses to the underlying FS.
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allow kernel media_rw_data_file:dir create_dir_perms;
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allow kernel media_rw_data_file:file create_file_perms;
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# Access to /data/misc/vold/virtual_disk.
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allow kernel vold_data_file:file read;
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###
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### neverallow rules
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###
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# The initial task starts in the kernel domain (assigned via
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# initial_sid_contexts), but nothing ever transitions to it.
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neverallow * kernel:process { transition dyntransition };
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# The kernel domain is never entered via an exec, nor should it
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# ever execute a program outside the rootfs without changing to another domain.
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# If you encounter an execute_no_trans denial on the kernel domain, then
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# possible causes include:
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# - The program is a kernel usermodehelper. In this case, define a domain
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# for the program and domain_auto_trans() to it.
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# - You are running an exploit which switched to the init task credentials
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# and is then trying to exec a shell or other program. You lose!
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neverallow kernel *:file { entrypoint execute_no_trans };
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# the kernel should not be accessing files owned by other users.
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# Instead of adding dac_{read_search,override}, fix the unix permissions
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# on files being accessed.
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neverallow kernel self:global_capability_class_set { dac_override dac_read_search };
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