Files
SukiSU-Ultra/kernel/allowlist.h
Juhyung Park bd8434f4f4 Hook improvements (take 2) (#563)
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>
2023-06-16 19:53:15 +08:00

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C

#ifndef __KSU_H_ALLOWLIST
#define __KSU_H_ALLOWLIST
#include "linux/types.h"
#include "ksu.h"
void ksu_allowlist_init(void);
void ksu_allowlist_exit(void);
bool ksu_load_allow_list(void);
void ksu_show_allow_list(void);
bool __ksu_is_allow_uid(uid_t uid);
#define ksu_is_allow_uid(uid) unlikely(__ksu_is_allow_uid(uid))
bool ksu_get_allow_list(int *array, int *length, bool allow);
void ksu_prune_allowlist(bool (*is_uid_exist)(uid_t, void *), void *data);
bool ksu_get_app_profile(struct app_profile *);
bool ksu_set_app_profile(struct app_profile *, bool persist);
bool ksu_uid_should_umount(uid_t uid);
struct root_profile *ksu_get_root_profile(uid_t uid);
#endif