71 lines
1.3 KiB
C
71 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* livepatch-sample.c - Kernel Live Patching Sample Module
|
|
*
|
|
* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/livepatch.h>
|
|
|
|
/*
|
|
* This (dumb) live patch overrides the function that prints the
|
|
* kernel boot cmdline when /proc/cmdline is read.
|
|
*
|
|
* Example:
|
|
*
|
|
* $ cat /proc/cmdline
|
|
* <your cmdline>
|
|
*
|
|
* $ insmod livepatch-sample.ko
|
|
* $ cat /proc/cmdline
|
|
* this has been live patched
|
|
*
|
|
* $ echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled
|
|
* $ cat /proc/cmdline
|
|
* <your cmdline>
|
|
*/
|
|
|
|
#include <linux/seq_file.h>
|
|
static int livepatch_cmdline_proc_show(struct seq_file *m, void *v)
|
|
{
|
|
seq_printf(m, "%s\n", "this has been live patched");
|
|
return 0;
|
|
}
|
|
|
|
static struct klp_func funcs[] = {
|
|
{
|
|
.old_name = "cmdline_proc_show",
|
|
.new_func = livepatch_cmdline_proc_show,
|
|
}, { }
|
|
};
|
|
|
|
static struct klp_object objs[] = {
|
|
{
|
|
/* name being NULL means vmlinux */
|
|
.funcs = funcs,
|
|
}, { }
|
|
};
|
|
|
|
static struct klp_patch patch = {
|
|
.mod = THIS_MODULE,
|
|
.objs = objs,
|
|
};
|
|
|
|
static int livepatch_init(void)
|
|
{
|
|
return klp_enable_patch(&patch);
|
|
}
|
|
|
|
static void livepatch_exit(void)
|
|
{
|
|
}
|
|
|
|
module_init(livepatch_init);
|
|
module_exit(livepatch_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_INFO(livepatch, "Y");
|