445 lines
11 KiB
C
445 lines
11 KiB
C
#include <linux/dcache.h>
|
|
#include <linux/security.h>
|
|
#include <asm/current.h>
|
|
#include <linux/cred.h>
|
|
#include <linux/err.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/kprobes.h>
|
|
#include <linux/types.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/version.h>
|
|
#include <linux/ptrace.h>
|
|
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
|
|
#include <linux/sched/task_stack.h>
|
|
#else
|
|
#include <linux/sched.h>
|
|
#endif
|
|
#ifdef CONFIG_KSU_SUSFS_SUS_SU
|
|
#include <linux/susfs_def.h>
|
|
#endif
|
|
|
|
#include "objsec.h"
|
|
#include "allowlist.h"
|
|
#include "arch.h"
|
|
#include "klog.h" // IWYU pragma: keep
|
|
#include "ksud.h"
|
|
#include "kernel_compat.h"
|
|
#include "sulog.h"
|
|
|
|
#define SU_PATH "/system/bin/su"
|
|
#define SH_PATH "/system/bin/sh"
|
|
|
|
extern void escape_to_root(void);
|
|
|
|
static const char sh_path[] = "/system/bin/sh";
|
|
static const char ksud_path[] = KSUD_PATH;
|
|
static const char su[] = SU_PATH;
|
|
|
|
bool ksu_sucompat_hook_state __read_mostly = true;
|
|
|
|
static inline void __user *userspace_stack_buffer(const void *d, size_t len)
|
|
{
|
|
/* To avoid having to mmap a page in userspace, just write below the stack
|
|
* pointer. */
|
|
char __user *p = (void __user *)current_user_stack_pointer() - len;
|
|
|
|
return copy_to_user(p, d, len) ? NULL : p;
|
|
}
|
|
|
|
static inline char __user *sh_user_path(void)
|
|
{
|
|
return userspace_stack_buffer(sh_path, sizeof(sh_path));
|
|
}
|
|
|
|
static inline char __user *ksud_user_path(void)
|
|
{
|
|
return userspace_stack_buffer(ksud_path, sizeof(ksud_path));
|
|
}
|
|
|
|
int ksu_handle_faccessat(int *dfd, const char __user **filename_user, int *mode,
|
|
int *__unused_flags)
|
|
{
|
|
|
|
#ifndef CONFIG_KSU_KPROBES_HOOK
|
|
if (!ksu_sucompat_hook_state) {
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
#ifndef CONFIG_KSU_SUSFS_SUS_SU
|
|
if (!ksu_is_allow_uid(current_uid().val)) {
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_KSU_SUSFS_SUS_SU
|
|
char path[sizeof(su) + 1] = {0};
|
|
#else
|
|
char path[sizeof(su) + 1];
|
|
memset(path, 0, sizeof(path));
|
|
#endif
|
|
ksu_strncpy_from_user_nofault(path, *filename_user, sizeof(path));
|
|
|
|
if (unlikely(!memcmp(path, su, sizeof(su)))) {
|
|
pr_info("faccessat su->sh!\n");
|
|
*filename_user = sh_user_path();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0) && defined(CONFIG_KSU_SUSFS_SUS_SU)
|
|
struct filename* susfs_ksu_handle_stat(int *dfd, const char __user **filename_user, int *flags) {
|
|
struct filename *name = getname_flags(*filename_user, getname_statx_lookup_flags(*flags), NULL);
|
|
|
|
if (unlikely(IS_ERR(name) || name->name == NULL)) {
|
|
return name;
|
|
}
|
|
|
|
if (likely(memcmp(name->name, su, sizeof(su)))) {
|
|
return name;
|
|
}
|
|
|
|
const char sh[] = SH_PATH;
|
|
pr_info("vfs_fstatat su->sh!\n");
|
|
memcpy((void *)name->name, sh, sizeof(sh));
|
|
return name;
|
|
}
|
|
#endif
|
|
|
|
int ksu_handle_stat(int *dfd, const char __user **filename_user, int *flags)
|
|
{
|
|
|
|
#ifndef CONFIG_KSU_KPROBES_HOOK
|
|
if (!ksu_sucompat_hook_state) {
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
#ifndef CONFIG_KSU_SUSFS_SUS_SU
|
|
if (!ksu_is_allow_uid(current_uid().val)) {
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
if (unlikely(!filename_user)) {
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_KSU_SUSFS_SUS_SU
|
|
char path[sizeof(su) + 1] = {0};
|
|
#else
|
|
char path[sizeof(su) + 1];
|
|
memset(path, 0, sizeof(path));
|
|
#endif
|
|
// Remove this later!! we use syscall hook, so this will never happen!!!!!
|
|
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 18, 0) && 0
|
|
// it becomes a `struct filename *` after 5.18
|
|
// https://elixir.bootlin.com/linux/v5.18/source/fs/stat.c#L216
|
|
const char sh[] = SH_PATH;
|
|
struct filename *filename = *((struct filename **)filename_user);
|
|
if (IS_ERR(filename)) {
|
|
return 0;
|
|
}
|
|
if (likely(memcmp(filename->name, su, sizeof(su))))
|
|
return 0;
|
|
pr_info("vfs_statx su->sh!\n");
|
|
memcpy((void *)filename->name, sh, sizeof(sh));
|
|
#else
|
|
ksu_strncpy_from_user_nofault(path, *filename_user, sizeof(path));
|
|
|
|
if (unlikely(!memcmp(path, su, sizeof(su)))) {
|
|
pr_info("newfstatat su->sh!\n");
|
|
*filename_user = sh_user_path();
|
|
}
|
|
#endif
|
|
|
|
return 0;
|
|
}
|
|
|
|
// the call from execve_handler_pre won't provided correct value for __never_use_argument, use them after fix execve_handler_pre, keeping them for consistence for manually patched code
|
|
int ksu_handle_execveat_sucompat(int *fd, struct filename **filename_ptr,
|
|
void *__never_use_argv, void *__never_use_envp,
|
|
int *__never_use_flags)
|
|
{
|
|
struct filename *filename;
|
|
uid_t current_uid_val = current_uid().val;
|
|
|
|
#ifndef CONFIG_KSU_KPROBES_HOOK
|
|
if (!ksu_sucompat_hook_state) {
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
if (unlikely(!filename_ptr))
|
|
return 0;
|
|
|
|
filename = *filename_ptr;
|
|
if (IS_ERR(filename)) {
|
|
return 0;
|
|
}
|
|
|
|
if (likely(memcmp(filename->name, su, sizeof(su))))
|
|
return 0;
|
|
|
|
bool is_allowed = ksu_is_allow_uid(current_uid_val);
|
|
|
|
#ifndef CONFIG_KSU_SUSFS_SUS_SU
|
|
if (!is_allowed)
|
|
return 0;
|
|
#endif
|
|
|
|
ksu_sulog_report_su_attempt(current_uid_val, NULL, filename->name, is_allowed);
|
|
|
|
if (!is_allowed) {
|
|
return 0;
|
|
}
|
|
|
|
pr_info("do_execveat_common su found\n");
|
|
memcpy((void *)filename->name, ksud_path, sizeof(ksud_path));
|
|
|
|
escape_to_root();
|
|
|
|
return 0;
|
|
}
|
|
|
|
int ksu_handle_execve_sucompat(int *fd, const char __user **filename_user,
|
|
void *__never_use_argv, void *__never_use_envp,
|
|
int *__never_use_flags)
|
|
{
|
|
uid_t current_uid_val = current_uid().val;
|
|
//const char su[] = SU_PATH;
|
|
#ifdef CONFIG_KSU_SUSFS_SUS_SU
|
|
char path[sizeof(su) + 1] = {0};
|
|
#else
|
|
char path[sizeof(su) + 1];
|
|
#endif
|
|
|
|
#ifndef CONFIG_KSU_KPROBES_HOOK
|
|
if (!ksu_sucompat_hook_state) {
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
if (unlikely(!filename_user))
|
|
return 0;
|
|
|
|
/*
|
|
* nofault variant fails silently due to pagefault_disable
|
|
* some cpus dont really have that good speculative execution
|
|
* access_ok to substitute set_fs, we check if pointer is accessible
|
|
*/
|
|
if (!ksu_access_ok(*filename_user, sizeof(path)))
|
|
return 0;
|
|
|
|
// success = returns number of bytes and should be less than path
|
|
long len = strncpy_from_user(path, *filename_user, sizeof(path));
|
|
if (len <= 0 || len > sizeof(path))
|
|
return 0;
|
|
// strncpy_from_user_nofault does this too
|
|
path[sizeof(path) - 1] = '\0';
|
|
|
|
if (likely(memcmp(path, su, sizeof(su))))
|
|
return 0;
|
|
|
|
bool is_allowed = ksu_is_allow_uid(current_uid_val);
|
|
|
|
ksu_sulog_report_su_attempt(current_uid_val, NULL, path, is_allowed);
|
|
|
|
if (!is_allowed)
|
|
return 0;
|
|
|
|
pr_info("sys_execve su found\n");
|
|
*filename_user = ksud_user_path();
|
|
|
|
escape_to_root();
|
|
|
|
return 0;
|
|
}
|
|
|
|
// dummified
|
|
int ksu_handle_devpts(struct inode *inode)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
int __ksu_handle_devpts(struct inode *inode)
|
|
{
|
|
|
|
#ifndef CONFIG_KSU_KPROBES_HOOK
|
|
if (!ksu_sucompat_hook_state)
|
|
return 0;
|
|
#endif
|
|
|
|
if (!current->mm) {
|
|
return 0;
|
|
}
|
|
|
|
uid_t uid = current_uid().val;
|
|
if (uid % 100000 < 10000) {
|
|
// not untrusted_app, ignore it
|
|
return 0;
|
|
}
|
|
|
|
if (likely(!ksu_is_allow_uid(uid)))
|
|
return 0;
|
|
|
|
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 1, 0) || defined(KSU_OPTIONAL_SELINUX_INODE)
|
|
struct inode_security_struct *sec = selinux_inode(inode);
|
|
#else
|
|
struct inode_security_struct *sec =
|
|
(struct inode_security_struct *)inode->i_security;
|
|
#endif
|
|
if (ksu_devpts_sid && sec)
|
|
sec->sid = ksu_devpts_sid;
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_KSU_KPROBES_HOOK
|
|
|
|
static int faccessat_handler_pre(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct pt_regs *real_regs = PT_REAL_REGS(regs);
|
|
int *dfd = (int *)&PT_REGS_PARM1(real_regs);
|
|
const char __user **filename_user =
|
|
(const char **)&PT_REGS_PARM2(real_regs);
|
|
int *mode = (int *)&PT_REGS_PARM3(real_regs);
|
|
|
|
return ksu_handle_faccessat(dfd, filename_user, mode, NULL);
|
|
}
|
|
|
|
static int newfstatat_handler_pre(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct pt_regs *real_regs = PT_REAL_REGS(regs);
|
|
int *dfd = (int *)&PT_REGS_PARM1(real_regs);
|
|
const char __user **filename_user =
|
|
(const char **)&PT_REGS_PARM2(real_regs);
|
|
int *flags = (int *)&PT_REGS_SYSCALL_PARM4(real_regs);
|
|
|
|
return ksu_handle_stat(dfd, filename_user, flags);
|
|
}
|
|
|
|
static int execve_handler_pre(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct pt_regs *real_regs = PT_REAL_REGS(regs);
|
|
const char __user **filename_user =
|
|
(const char **)&PT_REGS_PARM1(real_regs);
|
|
|
|
return ksu_handle_execve_sucompat(AT_FDCWD, filename_user, NULL, NULL,
|
|
NULL);
|
|
}
|
|
|
|
static struct kprobe *su_kps[6];
|
|
static int pts_unix98_lookup_pre(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct inode *inode;
|
|
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0)
|
|
struct file *file = (struct file *)PT_REGS_PARM2(regs);
|
|
inode = file->f_path.dentry->d_inode;
|
|
#else
|
|
inode = (struct inode *)PT_REGS_PARM2(regs);
|
|
#endif
|
|
|
|
return ksu_handle_devpts(inode);
|
|
}
|
|
|
|
static struct kprobe *init_kprobe(const char *name,
|
|
kprobe_pre_handler_t handler)
|
|
{
|
|
struct kprobe *kp = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
|
|
if (!kp)
|
|
return NULL;
|
|
kp->symbol_name = name;
|
|
kp->pre_handler = handler;
|
|
|
|
int ret = register_kprobe(kp);
|
|
pr_info("sucompat: register_%s kprobe: %d\n", name, ret);
|
|
if (ret) {
|
|
kfree(kp);
|
|
return NULL;
|
|
}
|
|
|
|
return kp;
|
|
}
|
|
|
|
static void destroy_kprobe(struct kprobe **kp_ptr)
|
|
{
|
|
struct kprobe *kp = *kp_ptr;
|
|
if (!kp)
|
|
return;
|
|
unregister_kprobe(kp);
|
|
synchronize_rcu();
|
|
kfree(kp);
|
|
*kp_ptr = NULL;
|
|
}
|
|
#endif
|
|
|
|
// sucompat: permited process can execute 'su' to gain root access.
|
|
void ksu_sucompat_init(void)
|
|
{
|
|
#ifdef CONFIG_KSU_KPROBES_HOOK
|
|
su_kps[0] = init_kprobe(SYS_EXECVE_SYMBOL, execve_handler_pre);
|
|
su_kps[1] = init_kprobe(SYS_EXECVE_COMPAT_SYMBOL, execve_handler_pre);
|
|
su_kps[2] = init_kprobe(SYS_FACCESSAT_SYMBOL, faccessat_handler_pre);
|
|
su_kps[3] = init_kprobe(SYS_NEWFSTATAT_SYMBOL, newfstatat_handler_pre);
|
|
su_kps[4] = init_kprobe(SYS_FSTATAT64_SYMBOL, newfstatat_handler_pre);
|
|
su_kps[5] = init_kprobe("pts_unix98_lookup", pts_unix98_lookup_pre);
|
|
#else
|
|
ksu_sucompat_hook_state = true;
|
|
pr_info("ksu_sucompat init\n");
|
|
#endif
|
|
}
|
|
|
|
void ksu_sucompat_exit(void)
|
|
{
|
|
#ifdef CONFIG_KSU_KPROBES_HOOK
|
|
int i;
|
|
for (i = 0; i < ARRAY_SIZE(su_kps); i++) {
|
|
destroy_kprobe(&su_kps[i]);
|
|
}
|
|
#else
|
|
ksu_sucompat_hook_state = false;
|
|
pr_info("ksu_sucompat exit\n");
|
|
#endif
|
|
}
|
|
|
|
#ifdef CONFIG_KSU_SUSFS_SUS_SU
|
|
extern bool ksu_su_compat_enabled;
|
|
bool ksu_devpts_hook = false;
|
|
bool susfs_is_sus_su_hooks_enabled __read_mostly = false;
|
|
int susfs_sus_su_working_mode = 0;
|
|
|
|
static bool ksu_is_su_kps_enabled(void) {
|
|
#ifdef CONFIG_KSU_KPROBES_HOOK
|
|
int i;
|
|
for (i = 0; i < ARRAY_SIZE(su_kps); i++) {
|
|
if (su_kps[i]) {
|
|
return true;
|
|
}
|
|
}
|
|
#endif
|
|
return false;
|
|
}
|
|
|
|
void ksu_susfs_disable_sus_su(void) {
|
|
susfs_is_sus_su_hooks_enabled = false;
|
|
ksu_devpts_hook = false;
|
|
susfs_sus_su_working_mode = SUS_SU_DISABLED;
|
|
// Re-enable the su_kps for user, users need to toggle off the kprobe hooks again in ksu manager if they want it disabled.
|
|
if (!ksu_is_su_kps_enabled()) {
|
|
ksu_sucompat_init();
|
|
ksu_su_compat_enabled = true;
|
|
}
|
|
}
|
|
|
|
void ksu_susfs_enable_sus_su(void) {
|
|
if (ksu_is_su_kps_enabled()) {
|
|
ksu_sucompat_exit();
|
|
ksu_su_compat_enabled = false;
|
|
}
|
|
susfs_is_sus_su_hooks_enabled = true;
|
|
ksu_devpts_hook = true;
|
|
susfs_sus_su_working_mode = SUS_SU_WITH_HOOKS;
|
|
}
|
|
#endif // #ifdef CONFIG_KSU_SUSFS_SUS_SU
|