Files
SukiSU-Ultra/kernel/kernel_compat.h
ShirkNeko dd1eb98963 kernel: sucompat: increase reliability, commonize and micro-optimize tiann #2656
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.

Apply the susfs patch

This does NOT seem to affect newer ARMv8.2+ CPUs (A75/A76 and newer)

My speculation? ARMv8.0 has weak speculation :)

here we replace `ksu_strncpy_from_user_nofault` with ksu_strncpy_from_user_retry:
- ksu_strncpy_from_user_nofault as fast-path copy
- fallback to access_ok to validate the pointer + strncpy_from_user
- 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

basically, we retry on pagefualt

for usercopies, its not like were doing
    memset(dest, 0, sizeof(dest));
    strncat(dest, var, bytes);

that memset seems unneeded. instead we use strncpy itself to do proper
error and oob check and null term it after.

as for optimizations
- just return early if unauthorized
- commonized logic
- reduced duplication

Tested on:
- ARMv8.0 A73.a53, A57.a53, A53.a53
- ARMv8.2 A76.a55

Stale: tiann #2656

Co-authored-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
Co-authored-by: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>
Co-authored-by: rsuntk <rsuntk@yukiprjkt.my.id>
Signed-off-by: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>
2025-09-25 19:41:26 +08:00

83 lines
2.6 KiB
C

#ifndef __KSU_H_KERNEL_COMPAT
#define __KSU_H_KERNEL_COMPAT
#include <linux/fs.h>
#include <linux/version.h>
#include <linux/cred.h>
#include "ss/policydb.h"
#include "linux/key.h"
/**
* list_count_nodes - count the number of nodes in a list
* @head: the head of the list
*
* This function iterates over the list starting from @head and counts
* the number of nodes in the list. It does not modify the list.
*
* Context: Any context. The function is safe to call in any context,
* including interrupt context, as it does not sleep or allocate
* memory.
*
* Return: the number of nodes in the list (excluding the head)
*/
#if LINUX_VERSION_CODE < KERNEL_VERSION(6, 6, 0)
static inline __maybe_unused size_t list_count_nodes(const struct list_head *head)
{
const struct list_head *pos;
size_t count = 0;
if (!head)
return 0;
list_for_each(pos, head)
count++;
return count;
}
#endif
/*
* Adapt to Huawei HISI kernel without affecting other kernels ,
* Huawei Hisi Kernel EBITMAP Enable or Disable Flag ,
* From ss/ebitmap.h
*/
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)) && \
(LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0)) || \
(LINUX_VERSION_CODE >= KERNEL_VERSION(4, 14, 0)) && \
(LINUX_VERSION_CODE < KERNEL_VERSION(4, 15, 0))
#ifdef HISI_SELINUX_EBITMAP_RO
#define CONFIG_IS_HW_HISI
#endif
#endif
// Checks for UH, KDP and RKP
#ifdef SAMSUNG_UH_DRIVER_EXIST
#if defined(CONFIG_UH) || defined(CONFIG_KDP) || defined(CONFIG_RKP)
#error "CONFIG_UH, CONFIG_KDP and CONFIG_RKP is enabled! Please disable or remove it before compile a kernel with KernelSU!"
#endif
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0) || \
defined(CONFIG_IS_HW_HISI) || \
defined(CONFIG_KSU_ALLOWLIST_WORKAROUND)
extern struct key *init_session_keyring;
#endif
extern void ksu_android_ns_fs_check(void);
extern struct file *ksu_filp_open_compat(const char *filename, int flags,
umode_t mode);
extern ssize_t ksu_kernel_read_compat(struct file *p, void *buf, size_t count,
loff_t *pos);
extern ssize_t ksu_kernel_write_compat(struct file *p, const void *buf,
size_t count, loff_t *pos);
extern long ksu_copy_from_user_nofault(void *dst, const void __user *src, size_t size);
extern long ksu_copy_from_user_retry(void *to, const void __user *from, unsigned long count);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 0, 0)
#define ksu_access_ok(addr, size) access_ok(addr, size)
#else
#define ksu_access_ok(addr, size) access_ok(VERIFY_READ, addr, size)
#endif
#endif