4c6b13508d
The kernel, when it creates a loop block device, starts a new
kernel thread "loop0" (drivers/block/loop.c). This kernel thread,
which performs writes on behalf of other processes, needs read/write
privileges to the sdcard. Allow it.
Steps to reproduce:
0) Get device with external, removable sdcard
1) Run: "adb install -s foo.apk"
Expected:
APK installs successfully.
Actual:
APK fails to install. Error message:
Vold E Failed to write superblock (I/O error)
loop0 W type=1400 audit(0.0:3123): avc: denied { read } for path="/mnt/secure/asec/smdl1645334795.tmp.asec" dev="mmcblk1p1" ino=528 scontext=u:r:kernel:s0 tcontext=u:object_r:vfat:s0 tclass=file permissive=0
PackageHelper E Failed to create secure container smdl1645334795.tmp
DefContainer E Failed to create container smdl1645334795.tmp
Bug: 17158723
Change-Id: I4aa86e372cc55348f6b8becfa17bd4da583925d4
60 lines
2.2 KiB
Text
60 lines
2.2 KiB
Text
# Life begins with the kernel.
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type kernel, domain;
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# Run /init before we have switched domains.
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allow kernel rootfs:file execute_no_trans;
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# setcon to init domain.
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allow kernel self:process setcurrent;
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allow kernel init:process dyntransition;
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# The kernel is unconfined.
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unconfined_domain(kernel)
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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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# init direct restorecon calls prior to switching to init domain
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# /dev and /dev/socket
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allow kernel { device socket_device }:dir relabelto;
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# /dev/__properties__
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allow kernel properties_device:file relabelto;
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# /sys
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allow kernel sysfs:{ dir file lnk_file } relabelfrom;
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allow kernel sysfs_type:{ dir file lnk_file } relabelto;
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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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# Set checkreqprot by init.rc prior to switching to init domain.
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allow kernel self:security setcheckreqprot;
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# MTP sync (b/15835289)
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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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###
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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 domain 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 failed to setcon u:r:init:s0 in your init.rc and thus your init
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# program was left in the kernel domain and is now trying to execute
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# some other program. Fix your init.rc file.
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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_type fs_type -rootfs }:file { entrypoint execute_no_trans };
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