cregit-Linux how code gets into the kernel

Release 4.10 samples/livepatch/livepatch-sample.c

/*
 * livepatch-sample.c - Kernel Live Patching Sample Module
 *
 * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#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; }

Contributors

PersonTokensPropCommitsCommitProp
seth jenningsseth jennings27100.00%1100.00%
Total27100.00%1100.00%

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) { int ret; ret = klp_register_patch(&patch); if (ret) return ret; ret = klp_enable_patch(&patch); if (ret) { WARN_ON(klp_unregister_patch(&patch)); return ret; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
seth jenningsseth jennings55100.00%1100.00%
Total55100.00%1100.00%


static void livepatch_exit(void) { WARN_ON(klp_disable_patch(&patch)); WARN_ON(klp_unregister_patch(&patch)); }

Contributors

PersonTokensPropCommitsCommitProp
seth jenningsseth jennings26100.00%1100.00%
Total26100.00%1100.00%

module_init(livepatch_init); module_exit(livepatch_exit); MODULE_LICENSE("GPL"); MODULE_INFO(livepatch, "Y");

Overall Contributors

PersonTokensPropCommitsCommitProp
seth jenningsseth jennings19396.02%133.33%
jessica yujessica yu73.48%133.33%
josh poimboeufjosh poimboeuf10.50%133.33%
Total201100.00%3100.00%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.