kprobes: Use helper to parse boolean input from userspace

The "enabled" file provides a debugfs interface to arm / disarm kprobes in the kernel. In order to parse the buffer containing the values written from userspace, the callback manually parses the user input to convert it to a boolean value. As taking a string value from userspace and converting it to boolean is a common operation, a helper kstrtobool_from_user() is already available in the kernel. Update the callback to use the common helper to parse the write buffer from userspace. Link: https://lkml.kernel.org/r/163163032637.489837.10678039554832855327.stgit@devnote2

Punit Agrawal committed 5 years ago

Commit 5d6de7d1 parent 8f7262c1 file · +6 −22Browse files

Unified · Split

kernel/kprobes.c+6−22

@@ -2770,30 +2770,14 @@ static ssize_t read_enabled_file_bool(struct file *file, · 2769 unmodified lines
2770	static ssize_t write_enabled_file_bool(struct file *file,	2770	static ssize_t write_enabled_file_bool(struct file *file,
2771	const char __user user_buf, size_t count, loff_t ppos)	2771	const char __user user_buf, size_t count, loff_t ppos)
2772	{	2772	{
2773	char buf[32];	2773	bool enable;
2774	size_t buf_size;	2774	int ret;
2775	int ret = 0;
2776
2777	buf_size = min(count, (sizeof(buf)-1));
2778	if (copy_from_user(buf, user_buf, buf_size))
2779	return -EFAULT;
2780		2775
2781	buf[buf_size] = '\0';	2776	ret = kstrtobool_from_user(user_buf, count, &enable);
2782	switch (buf[0]) {	2777	if (ret)
2783	case 'y':	2778	return ret;
2784	case 'Y':
2785	case '1':
2786	ret = arm_all_kprobes();
2787	break;
2788	case 'n':
2789	case 'N':
2790	case '0':
2791	ret = disarm_all_kprobes();
2792	break;
2793	default:
2794	return -EINVAL;
2795	}
2796		2779
		2780	ret = enable ? arm_all_kprobes() : disarm_all_kprobes();
2797	if (ret)	2781	if (ret)
2798	return ret;	2782	return ret;
2799		2783