Commit 5d6de7d7 authored by Punit Agrawal's avatar Punit Agrawal Committed by Steven Rostedt (VMware)
Browse files

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



Signed-off-by: default avatarPunit Agrawal <punitagrawal@gmail.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 8f7262cd

kernel/kprobes.c

+6 −22
Original line number Diff line number Diff line
@@ -2770,30 +2770,14 @@ static ssize_t read_enabled_file_bool(struct file *file, 
static ssize_t write_enabled_file_bool(struct file *file,

	       const char __user *user_buf, size_t count, loff_t *ppos)

{

	char buf[32];

	size_t buf_size;

	int ret = 0;



	buf_size = min(count, (sizeof(buf)-1));

	if (copy_from_user(buf, user_buf, buf_size))

		return -EFAULT;

	bool enable;

	int ret;



	buf[buf_size] = '\0';

	switch (buf[0]) {

	case 'y':

	case 'Y':

	case '1':

		ret = arm_all_kprobes();

		break;

	case 'n':

	case 'N':

	case '0':

		ret = disarm_all_kprobes();

		break;

	default:

		return -EINVAL;

	}

	ret = kstrtobool_from_user(user_buf, count, &enable);

	if (ret)

		return ret;



	ret = enable ? arm_all_kprobes() : disarm_all_kprobes();

	if (ret)

		return ret;