Files
SukiSU-Ultra/kernel/kernel_compat.h
backslashxx d288b8f24f ksud: migrate ksud execution to security_bprm_check (tiann#2653)
This migrates ksud execution decision-making to bprm_check_security.
This requires passing proper argv and envp to a modified _ksud handler
aptly named 'ksu_handle_bprm_ksud'.

Introduces:
int ksu_handle_bprm_ksud(const char *filename, const char *argv1,
const char *envp, size_t envp_len)

which is adapted from:
int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
struct user_arg_ptr *argv,
struct user_arg_ptr *envp,
int *flags)

ksu_handle_bprm_ksud handles all the decision making, it decides when it is
time to apply_kernelsu_rules depending if it sees "second_stage".

For LSM hook, turns out we can pull out argv and envp from mm_struct.
The code in here explains itself on how to do it.

whole blob exists on arg_start to arg_end, so we just pull it out and grab next
array after the first null terminator.

as for envp, we pass the pointer then hunt for it when needed

My reasoning on adding a fallback on usercopy is that on some devices a fault
happens, and it copies garbled data. On my creation of this, I actually had to lock
that _nofault copy on a spinlock as a way to mimic preempt_disable/enable without
actually doing it. As per user reports, no failed _nofault copies anyway but we
have-to-have a fallback for resilience.

References:
- old version1 6efcd8193e
- old version2 37d5938e66
- bad usercopy #21

This now provides a small helper function, ksu_copy_from_user_retry, which explains
itself. First we attempt a _nofault copy, if that fails, we try plain.

With that, It also provides an inlined copy_from_user_nofault for < 5.8.

While using strncpy_from_user_nofault was considered, this wont do, this will
only copy up to the first \0.

devlog:
16e5dce9e7...16c1f5f521
28642e60d7...728de0c571

References:
https://elixir.bootlin.com/linux/v4.14.1/source/include/linux/mm_types.h#L429
https://elixir.bootlin.com/linux/v4.14.1/source/include/linux/lsm_hooks.h

Stale: https://github.com/tiann/KernelSU/pull/2653

Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
2025-09-22 23:21:47 +08:00

104 lines
3.1 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
extern long ksu_strncpy_from_user_nofault(char *dst,
const void __user *unsafe_addr,
long count);
extern long ksu_strncpy_from_user_retry(char *dst,
const void __user *unsafe_addr,
long count);
#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);
/*
* ksu_copy_from_user_retry
* try nofault copy first, if it fails, try with plain
* paramters are the same as copy_from_user
* 0 = success
*/
static long ksu_copy_from_user_retry(void *to,
const void __user *from, unsigned long count)
{
long ret = ksu_copy_from_user_nofault(to, from, count);
if (likely(!ret))
return ret;
// we faulted! fallback to slow path
return copy_from_user(to, from, 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