kernel: 1. use prctl lsm hook; 2. refine sucompat hook

kernel/kprobe_hook.c

@@ -0,0 +1,46 @@
+#include <linux/version.h>
+#include <linux/kprobes.h>
+
+#include "arch.h"
+#include "ksu.h"
+#include "klog.h"
+
+static int handler_pre(struct kprobe *p, struct pt_regs *regs)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 16, 0)
+	struct pt_regs *real_regs = (struct pt_regs *)PT_REGS_PARM1(regs);
+#else
+	struct pt_regs *real_regs = regs;
+#endif
+	int option = (int)PT_REGS_PARM1(real_regs);
+	unsigned long arg2 = (unsigned long)PT_REGS_PARM2(real_regs);
+	unsigned long arg3 = (unsigned long)PT_REGS_PARM3(real_regs);
+	unsigned long arg4 = (unsigned long)PT_REGS_PARM4(real_regs);
+	unsigned long arg5 = (unsigned long)PT_REGS_PARM5(real_regs);
+
+	return ksu_handle_prctl(option, arg2, arg3, arg4, arg5);
+}
+
+static struct kprobe kp = {
+	.symbol_name = PRCTL_SYMBOL,
+	.pre_handler = handler_pre,
+};
+
+__maybe_unused int ksu_kprobe_init()
+{
+	int rc = 0;
+	rc = register_kprobe(&kp);
+
+	if (rc) {
+		pr_info("prctl kprobe failed: %d, please check your kernel config.\n",
+			rc);
+		return rc;
+	}
+
+    return rc;
+}
+
+__maybe_unused int ksu_kprobe_exit() {
+	unregister_kprobe(&kp);
+    return 0;
+}