* Since it's interceptable from LSM Hook,
then we just need to remove ksu_handle_devpts and
make a decoy for it.
Signed-off-by: rsuntk <rsuntk@yukiprjkt.my.id>
On plain ARMv8.0 devices (A53,A57,A73), strncpy_from_user_nofault() sometimes
fails to copy `filename_user` string correctly. This breaks su ofc, breaking
some apps like Termux (Play Store ver), ZArchiver and Root Explorer.
This does NOT seem to affect newer ARMv8.2+ CPUs (A75/A76 and newer)
My speculation? ARMv8.0 has weak speculation :)
here we replace `strncpy_from_user_nofault()` with another routine:
- access_ok() to validate the pointer
- strncpy_from_user() to copy and validate string
- manual null-termination just in case, as strncpy_from_user_nofault also does it
- remove that memset, seems useless as it is an strncpy, not strncat
Kind of mimicking _nofault, but yes with this one we allow pagefaults.
Tested on:
- ARMv8.0 A73.a53, A57.a53, A53.a53
- ARMv8.2 A76.a55
Tested-by: iDead XD <rafifirdaus12bb@gmail.com>
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
1. Replace `do_execveat_common` with `sys_execve` and `sys_execveat`
2. Replace `input_handle_event` with `input_event` and
`input_inject_event`
Tested on android12-5.10-2024-04, android13-5.15-2024-04.
android14-6.1-2024-04
Otherwise we will rewrite paths for filenames that begins with
`/system/bin/su`.
This fix copies one extra byte from userspace filename so that when we
encounter filenames like `/system/bin/suasf`,
`/system/bin/su\0` gets compared with `/system/bin/sua`, which correctly
prevents the `su -> sh` path rewriting.
Close#957
Hi @tiann.
Thanks for the great project, I had great fun playing around with it.
This PR mainly tries to further minimize the possible delays caused by
KernelSU hooking.
There are 3 major changes:
- Processes with 0 < UID < 2000 are blocked straight-up before going
through the allow_list.
I don't see any need for such processes to be interested in root, and
this allows returning early before going through a more expensive
lookup.
If there's an expected breakage due to this change, I'll remove it. Let
me know.
- A page-sized (4K) bitmap is added.
This allows O(1) lookup for UID <= 32767.
This speeds up `ksu_is_allow_uid()` by about 4.8x by sacrificing a 4K
memory. IMHO, a good trade-off.
Most notably, this reduces the 99.999% result previously from worrying
milliseconds scale to microseconds scale.
For UID > 32767, another page-sized (4K) sequential array is used to
cache allow_list.
Compared to the previous PR #557, this new approach gives another nice
25% performance boost in average, 63-96% boost in worst cases.
Benchmark results are available at
https://docs.google.com/spreadsheets/d/1w_tO1zRLPNMFRer49pL1TQfL6ndEhilRrDU1XFIcWXY/edit?usp=sharing
Thanks!
---------
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
- task_stack() had been separated when it was in Linux 4.11, so let's do
our migration when KernelSU facing the old version of kernel.
- See f3ac606719
Signed-off-by: Calling <KeternalGithub@163.com>
Signed-off-by: Calling <KeternalGithub@163.com>
