kernel: Allow to re-enable sucompat

kernel/sucompat.c

@@ -200,19 +200,7 @@ int ksu_handle_devpts(struct inode *inode)
 
 #ifdef CONFIG_KPROBES
 
-__maybe_unused static int faccessat_handler_pre(struct kprobe *p,
+static int faccessat_handler_pre(struct kprobe *p, struct pt_regs *regs)
-						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)
 {
 	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,
+static int newfstatat_handler_pre(struct kprobe *p, struct pt_regs *regs)
-						 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)
 {
 	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;
+	su_kps[0] = init_kprobe(SYS_EXECVE_SYMBOL, execve_handler_pre);
-	ret = register_kprobe(&execve_kp);
+	su_kps[1] = init_kprobe(SYS_FACCESSAT_SYMBOL, faccessat_handler_pre);
-	pr_info("sucompat: execve_kp: %d\n", ret);
+	su_kps[2] = init_kprobe(SYS_NEWFSTATAT_SYMBOL, newfstatat_handler_pre);
-	ret = register_kprobe(&newfstatat_kp);
+	su_kps[3] = init_kprobe("pts_unix98_lookup", pts_unix98_lookup_pre);
-	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);
 #endif
 }
 
 void ksu_sucompat_exit()
 {
 #ifdef CONFIG_KPROBES
-	unregister_kprobe(&execve_kp);
+	for (int i = 0; i < ARRAY_SIZE(su_kps); i++) {
-	unregister_kprobe(&newfstatat_kp);
+		destroy_kprobe(&su_kps[i]);
-	unregister_kprobe(&faccessat_kp);
+	}
-	unregister_kprobe(&pts_unix98_lookup_kp);
 #endif
 }

manager/app/src/main/java/com/rifsxd/ksunext/ui/screen/Settings.kt

@@ -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)) {