kernel: Allow to re-enable sucompat

This commit is contained in:
weishu
2025-02-16 21:33:26 +08:00
committed by rifsxd
parent d05d16c15d
commit 85866848ea
2 changed files with 37 additions and 110 deletions

View File

@@ -200,19 +200,7 @@ int ksu_handle_devpts(struct inode *inode)
#ifdef CONFIG_KPROBES
__maybe_unused static int faccessat_handler_pre(struct kprobe *p,
struct pt_regs *regs)
{
int *dfd = (int *)&PT_REGS_PARM1(regs);
const char __user **filename_user = (const char **)&PT_REGS_PARM2(regs);
int *mode = (int *)&PT_REGS_PARM3(regs);
// Both sys_ and do_ is C function
int *flags = (int *)&PT_REGS_CCALL_PARM4(regs);
return ksu_handle_faccessat(dfd, filename_user, mode, flags);
}
static int sys_faccessat_handler_pre(struct kprobe *p, struct pt_regs *regs)
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);
@@ -223,23 +211,7 @@ static int sys_faccessat_handler_pre(struct kprobe *p, struct pt_regs *regs)
return ksu_handle_faccessat(dfd, filename_user, mode, NULL);
}
__maybe_unused static int newfstatat_handler_pre(struct kprobe *p,
struct pt_regs *regs)
{
int *dfd = (int *)&PT_REGS_PARM1(regs);
const char __user **filename_user = (const char **)&PT_REGS_PARM2(regs);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
// static int vfs_statx(int dfd, const char __user *filename, int flags, struct kstat *stat, u32 request_mask)
int *flags = (int *)&PT_REGS_PARM3(regs);
#else
// int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,int flag)
int *flags = (int *)&PT_REGS_CCALL_PARM4(regs);
#endif
return ksu_handle_stat(dfd, filename_user, flags);
}
static int sys_newfstatat_handler_pre(struct kprobe *p, struct pt_regs *regs)
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);
@@ -250,17 +222,7 @@ static int sys_newfstatat_handler_pre(struct kprobe *p, struct pt_regs *regs)
return ksu_handle_stat(dfd, filename_user, flags);
}
// https://elixir.bootlin.com/linux/v5.10.158/source/fs/exec.c#L1864
static int execve_handler_pre(struct kprobe *p, struct pt_regs *regs)
{
int *fd = (int *)&PT_REGS_PARM1(regs);
struct filename **filename_ptr =
(struct filename **)&PT_REGS_PARM2(regs);
return ksu_handle_execveat_sucompat(fd, filename_ptr, NULL, NULL, NULL);
}
static int sys_execve_handler_pre(struct kprobe *p, struct pt_regs *regs)
{
struct pt_regs *real_regs = PT_REAL_REGS(regs);
const char __user **filename_user =
@@ -270,56 +232,6 @@ static int sys_execve_handler_pre(struct kprobe *p, struct pt_regs *regs)
NULL);
}
#if 1
static struct kprobe faccessat_kp = {
.symbol_name = SYS_FACCESSAT_SYMBOL,
.pre_handler = sys_faccessat_handler_pre,
};
#else
static struct kprobe faccessat_kp = {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 17, 0)
.symbol_name = "do_faccessat",
#else
.symbol_name = "sys_faccessat",
#endif
.pre_handler = faccessat_handler_pre,
};
#endif
#if 1
static struct kprobe newfstatat_kp = {
.symbol_name = SYS_NEWFSTATAT_SYMBOL,
.pre_handler = sys_newfstatat_handler_pre,
};
#else
static struct kprobe newfstatat_kp = {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
.symbol_name = "vfs_statx",
#else
.symbol_name = "vfs_fstatat",
#endif
.pre_handler = newfstatat_handler_pre,
};
#endif
#if 1
static struct kprobe execve_kp = {
.symbol_name = SYS_EXECVE_SYMBOL,
.pre_handler = sys_execve_handler_pre,
};
#else
static struct kprobe execve_kp = {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 9, 0)
.symbol_name = "do_execveat_common",
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 19, 0)
.symbol_name = "__do_execve_file",
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(3, 19, 0)
.symbol_name = "do_execveat_common",
#endif
.pre_handler = execve_handler_pre,
};
#endif
static int pts_unix98_lookup_pre(struct kprobe *p, struct pt_regs *regs)
{
struct inode *inode;
@@ -332,36 +244,52 @@ static int pts_unix98_lookup_pre(struct kprobe *p, struct pt_regs *regs)
return ksu_handle_devpts(inode);
}
static struct kprobe pts_unix98_lookup_kp = { .symbol_name =
"pts_unix98_lookup",
.pre_handler =
pts_unix98_lookup_pre };
#endif
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;
}
static struct kprobe *su_kps[4];
// sucompat: permited process can execute 'su' to gain root access.
void ksu_sucompat_init()
{
#ifdef CONFIG_KPROBES
int ret;
ret = register_kprobe(&execve_kp);
pr_info("sucompat: execve_kp: %d\n", ret);
ret = register_kprobe(&newfstatat_kp);
pr_info("sucompat: newfstatat_kp: %d\n", ret);
ret = register_kprobe(&faccessat_kp);
pr_info("sucompat: faccessat_kp: %d\n", ret);
ret = register_kprobe(&pts_unix98_lookup_kp);
pr_info("sucompat: devpts_kp: %d\n", ret);
su_kps[0] = init_kprobe(SYS_EXECVE_SYMBOL, execve_handler_pre);
su_kps[1] = init_kprobe(SYS_FACCESSAT_SYMBOL, faccessat_handler_pre);
su_kps[2] = init_kprobe(SYS_NEWFSTATAT_SYMBOL, newfstatat_handler_pre);
su_kps[3] = init_kprobe("pts_unix98_lookup", pts_unix98_lookup_pre);
#endif
}
void ksu_sucompat_exit()
{
#ifdef CONFIG_KPROBES
unregister_kprobe(&execve_kp);
unregister_kprobe(&newfstatat_kp);
unregister_kprobe(&faccessat_kp);
unregister_kprobe(&pts_unix98_lookup_kp);
for (int i = 0; i < ARRAY_SIZE(su_kps); i++) {
destroy_kprobe(&su_kps[i]);
}
#endif
}

View File

@@ -179,7 +179,6 @@ fun SettingScreen(navigator: DestinationsNavigator) {
title = stringResource(id = R.string.settings_disable_su),
summary = stringResource(id = R.string.settings_disable_su_summary),
checked = isSuDisabled,
enabled = !isSuDisabled // we can't re-enable su if it's disabled.
) { checked ->
val shouldEnable = !checked
if (Natives.setSuEnabled(shouldEnable)) {