We used to construct /sbin tmpfs overlay in early-init stage after
SELinux is properly initialized. However the way it is implemented
(forking daemon from magiskinit with complicated file waiting triggers)
is extremely complicated and error prone.
This commit moves the construction of the sbin overlay to pre-init
stage. The catch is that since SELinux is not present at that point,
proper selabel has to be reconstructed afterwards. Some additional
SEPolicy rules are added to make sure init can access magisk binaries,
and the secontext relabeling task is assigned to the main Magisk daemon.
Some stupid Samsung ROMs will spawn multiple zygote daemons. Since we
switched to ptrace based process monitoring, we have to know all zygote
processes to trace. This is an attempt to fix this issue.
Close#1272
Since Android Q does not allow launching activities from the background
(Services/BroadcastReceivers) and our native process is root, directly
launch activities and use it for communication between native and app.
The target activity is not exported, so non-root apps cannot send an
intent to fool Magisk Manager. This is as safe as the previous
implementation, which uses protected system broadcasts.
This also workaround broadcast limitations in many ROMs (especially
in Chinese ROMs) which blocks the su request dialog if the app is
frozen/force stopped by the system.
Close#1326
The root nodes are /system and /vendor. Adding new files into these
directories, although works on some devices, mostly bootloops on many
devices out there. So don't allow it, which also makes the whole magic
mounting logic much easier and extensible.
Samsung does not like running cmd before system services are started.
Instead of failing, it will enter an infinite wait on binder.
Move APK installation to boot complete to make sure pm can be run
without blocking process.
Forseeing the future that more and more A only system-as-root devices
would have similar bootloader behavior as the latest Samsung devices
(that is, no ramdisk will be loaded into memory when booting from
the boot partition), a solution/workaround has to be made when Magisk
is installed to the recovery partition, making custom recoveries
unable to co-exist with Magisk.
This commit allows magiskinit to read input device events from the
kernel to detect when a user holds volume key up to toggle whether
system-as-root mode is enabled. When system-as-root mode is disabled,
magiskinit will boot with ramdisk instead of cloning rootfs from system,
which in this case will boot to the recovery.
Some devices (mainly new Samsung phones we're talking here...) using
A only system-as-root refuse to load ramdisk when booted with boot
no matter what we do. With many A only system-as-root devices, even
though their boot image is kernel only, we can still be able to add
a ramdisk section into the image and force the kernel to use it as
rootfs. However the bootloader on devices like the S10 simply does
not load anything within boot image into memory other than the kernel.
This gives as the only option is to install Magisk on the recovery
partition. This commits adds proper support for these kind of scenarios.
It seems that even adding this to the list doesn't 100% works on all
devices out there, and some even reported crashes on several Google
services. Disable it for now and do further investigations in the future.
95%+ of existing modules enables auto mount (obviously).
Switching auto mount to opt-out makes more sense than opt-in as
in previous module format. The file 'auto_mount' will be ignored, and
the file 'skip_mount' will be checked to toggle the mounting behavior.
After scanning through the current Magisk Module Repo modules, no
modules are using custom bind mounting; all modules with auto mount
disabled have empty system folder, which means this change will not
affect any existing module.
It seems both Android cancers, Samsung and Huawei devices, don't
like preloading sepolicy. For a temporary solution now is to limit
the sepolicy loading to Android Q only.
Of course, the cancer of Android, Huawei, has to do some f**king weird
modifications to the Linux kernel. Its kernel only accepts 1 single
policy load in its lifetime, a second load will result in ENOMEM error.
Since Huawei devices always use their own stupid ramdisk setup and not
system-as-root, not loading sepolicy is not a concern (for now).
Android Q init assumes rootfs to always be on EXT4 images, thus
never runs restorecon on the whole root directory. This is an issue
because some folders in rootfs were set with special selabels in
the system partition, but when copying over to initramfs by magiskinit,
these labels will not be preserved.
So the solution is to relabel the files in rootfs with the original
context right? Yes, but rootfs does not allow security xattr to be set
on files before the kernel SELinux initializes with genfs_contexts.
We have to load our sepolicy to the kernel before we clone the root
directory from system partition, which we will also restore the selabel
in the meantime.
Unfortunately this means that for each reboot, the exact same policy
will be loaded to the kernel twice: once in magiskinit so we can label
rootfs properly, and once by the original init, which is part of the
boot procedure. There is no easy way to prevent init from loading
sepolicy, as init will refuse to continue if policy loading has failed.
