Previously, we use either BroadcastReceivers or Activities to receive
messages from our native daemon, but both have their own downsides.
Some OEMs blocks broadcasts if the app is not running in the background,
regardless of who the caller is. Activities on the other hand, despite
working 100% of the time, will steal the focus of the current foreground
app, even though we are just doing some logging and showing a toast.
In addition, since stubs for hiding Magisk Manager is introduced, our
only communication method is left with the broadcast option, as
only broadcasting allows targeting a specific package name, not a
component name (which will be obfuscated in the case of stubs).
To make sure root requests will work on all devices, Magisk had to do
some experiments every boot to test whether broadcast is deliverable or
not. This makes the whole thing even more complicated then ever.
So lets take a look at another kind of component in Android apps:
ContentProviders. It is a vital part of Android's ecosystem, and as far
as I know no OEMs will block requests to ContentProviders (or else
tons of functionality will break catastrophically). Starting at API 11,
the system supports calling a specific method in ContentProviders,
optionally sending extra data along with the method call. This is
perfect for the native daemon to start a communication with Magisk
Manager. Another cool thing is that we no longer need to know the
component name of the reciever, as ContentProviders identify themselves
with an "authority" name, which in Magisk Manager's case is tied to the
package name. We already have a mechanism to keep track of our current
manager package name, so this works out of the box.
So yay! No more flaky broadcast tests, no more stupid OEMs blocking
broadcasts for some bizzare reasons. This method should in theory
work on almost all devices and situations.
Running broadcast tests from the app does not accurately verifies
whether the broadcasts can be delivered when the app is not running in
the foreground, which is why we are running the test.
The only sane way to verify broadcasts is to trigger the broadcast test
directly from the daemon on boot complete. If it is not deliverable,
then activity mode shall be chosen.
In the meantime, cleanup AndroidManifest.xml
- `!= remain` shouldn't indicate "not signed", it should indicate a read error as with `!= hdr.length`
- attempt to catch unsigned images at signature read, before they make it to `BootSignature bootsig = new BootSignature(signature);` and result in the following:
java.io.IOException: unexpected end-of-contents marker
at org.bouncycastle.asn1.ASN1InputStream.readObject(Unknown Source:14)
at com.topjohnwu.signing.SignBoot$BootSignature.<init>(SignBoot.java:230)
at com.topjohnwu.signing.SignBoot.verifySignature(SignBoot.java:139)
at com.topjohnwu.signing.BootSigner.main(BootSigner.java:15)
at a.a.main(a.java:20)
- change to $TMPDIR in addon.d.sh since recovery addon.d-v1 backup + restore leaves you in /tmp/addon.d which the restore then deletes, which would break $BOOTSIGNER execution with the following:
libc: Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0 in tid 1078 (main), pid 1078 (main)
Segmentation fault
- also move $BOOTSIGNER execution to after `cd $MAGISKBIN` to ensure it's in a working directory in all cases
- addon.d.sh data mount wasn't doing anything since /data has to already be mounted for the script to be running, so move it into /system/addon.d/99-magisk.sh stub script where it might be useful on recoveries that don't mount /data initially
Fixes#2013
- increase SignBoot bootimg header version maximum from 4 to 8 (upstream AOSP is already at 3) and make a variable for future ease
- hdr read size of 1024 bytes was too small as hdr_v1 and hdr_v2 have increased the used header page areas to 1632 and 1648 bytes, respectively, so raise this to the minimum page size of 2048 and also make a variable for future ease
- do not return "not signed" for all caught exceptions, show StackTrace for future debugging then still return false for script purposes
- correct "test keys" boot image signing strings (scripts and app) to "verity keys"
- remove redundant addon.d.sh script bits that were covered elsewhere ($TMPDIR in util_functions.sh, find_dtbo_image in patch_dtbo_image)
- refactor addon.d.sh and flash_script.sh for simplicity and readability, and put common flashing script in util_functions.sh (as patch_boot_image), which should greatly help avoid them getting out of sync going forward and fixes compressing ramdisk support and post-patch cleanup for addon.d
- add check_data to addon.d.sh since moving stock_boot* and stock_dtbo* backups depend on it and so weren't occuring with addon.d
- fix find_manager_apk with working fallback for recovery addon.d execution (where `magisk --sqlite` will not work for hidden Manager), Manager DynAPK hiding, and print a useful log warning if an APK can't be found
- support unpack without decompression to allow easy testing of magiskboot's header, structure and hashing handling by comparing repack checksum versus origbootimg
- make -n first to match repack
According to this comment in #1880:
https://github.com/topjohnwu/Magisk/issues/1880#issuecomment-546657588
If Linux recycled our PPID, and coincidentally the process that reused
the PPID is root, AND init wants to kill the whole process group,
magiskd will get killed as a result.
There is no real way to block a SIGKILL signal, so we simply make sure
our daemon PID is the process group leader by renaming the directory.
Close#1880
On API 23+, the platform unifies the way to handle drawable
resources across processes: all drawables can be passed via Icon.
This allows us to send raw bitmap to the system without the need to
specify a resource ID. This means that we are allowed to NOT include
these drawable resources within our stub APK, since our full APK can
draw the images programmatically and send raw bitmaps to the system.
The plural form of the words 'documentation' and 'following' are used very rarely if ever and I don't believe that they should be used in this particular context.
