From 13d1cf7e702596e0cd8ec62afa6bd49c431f2d0c Mon Sep 17 00:00:00 2001 From: Seth Jennings Date: Tue, 16 Dec 2014 11:58:20 -0600 Subject: livepatch: samples: add sample live patching module Add a sample live patching module. Signed-off-by: Seth Jennings Reviewed-by: Miroslav Benes Reviewed-by: Petr Mladek Reviewed-by: Masami Hiramatsu Signed-off-by: Jiri Kosina --- samples/Kconfig | 7 +++ samples/Makefile | 2 +- samples/livepatch/Makefile | 1 + samples/livepatch/livepatch-sample.c | 87 ++++++++++++++++++++++++++++++++++++ 4 files changed, 96 insertions(+), 1 deletion(-) create mode 100644 samples/livepatch/Makefile create mode 100644 samples/livepatch/livepatch-sample.c (limited to 'samples') diff --git a/samples/Kconfig b/samples/Kconfig index 6181c2c..0aed20d 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -63,4 +63,11 @@ config SAMPLE_RPMSG_CLIENT to communicate with an AMP-configured remote processor over the rpmsg bus. +config SAMPLE_LIVE_PATCHING + tristate "Build live patching sample -- loadable modules only" + depends on LIVE_PATCHING && m + help + Builds a sample live patch that replaces the procfs handler + for /proc/cmdline to print "this has been live patched". + endif # SAMPLES diff --git a/samples/Makefile b/samples/Makefile index 1a60c62..f00257b 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -1,4 +1,4 @@ # Makefile for Linux samples code -obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ \ +obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ livepatch/ \ hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/ diff --git a/samples/livepatch/Makefile b/samples/livepatch/Makefile new file mode 100644 index 0000000..7f1cdc1 --- /dev/null +++ b/samples/livepatch/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SAMPLE_LIVE_PATCHING) += livepatch-sample.o diff --git a/samples/livepatch/livepatch-sample.c b/samples/livepatch/livepatch-sample.c new file mode 100644 index 0000000..21f159d --- /dev/null +++ b/samples/livepatch/livepatch-sample.c @@ -0,0 +1,87 @@ +/* + * livepatch-sample.c - Kernel Live Patching Sample Module + * + * Copyright (C) 2014 Seth Jennings + * + * 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 . + */ + +#include +#include +#include + +/* + * This (dumb) live patch overrides the function that prints the + * kernel boot cmdline when /proc/cmdline is read. + * + * Example: + * $ cat /proc/cmdline + * + * $ insmod livepatch-sample.ko + * $ cat /proc/cmdline + * this has been live patched + * $ echo 0 > /sys/kernel/livepatch/klp_sample/enabled + * + */ + +#include +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) +{ + 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; +} + +static void livepatch_exit(void) +{ + WARN_ON(klp_disable_patch(&patch)); + WARN_ON(klp_unregister_patch(&patch)); +} + +module_init(livepatch_init); +module_exit(livepatch_exit); +MODULE_LICENSE("GPL"); -- cgit v1.1 From 700a3048aaa394b2a6d1468430f892151ce04a01 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 23 Dec 2014 17:06:43 -0600 Subject: livepatch: samples: fix usage example comments Fix a few typos in the livepatch-sample.c usage example comments and add some whitespace to make the comments a little more legible. Reported-by: Udo Seidel Signed-off-by: Josh Poimboeuf Signed-off-by: Jiri Kosina --- samples/livepatch/livepatch-sample.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'samples') diff --git a/samples/livepatch/livepatch-sample.c b/samples/livepatch/livepatch-sample.c index 21f159d..fb8c861 100644 --- a/samples/livepatch/livepatch-sample.c +++ b/samples/livepatch/livepatch-sample.c @@ -26,12 +26,16 @@ * kernel boot cmdline when /proc/cmdline is read. * * Example: + * * $ cat /proc/cmdline * + * * $ insmod livepatch-sample.ko * $ cat /proc/cmdline * this has been live patched - * $ echo 0 > /sys/kernel/livepatch/klp_sample/enabled + * + * $ echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled + * $ cat /proc/cmdline * */ -- cgit v1.1 From 12cf89b550d13eb7cb86ef182bd6c04345a33a1f Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 3 Feb 2015 16:45:18 -0600 Subject: livepatch: rename config to CONFIG_LIVEPATCH Rename CONFIG_LIVE_PATCHING to CONFIG_LIVEPATCH to make the naming of the config and the code more consistent. Signed-off-by: Josh Poimboeuf Reviewed-by: Jingoo Han Signed-off-by: Jiri Kosina --- samples/Kconfig | 4 ++-- samples/livepatch/Makefile | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'samples') diff --git a/samples/Kconfig b/samples/Kconfig index 0aed20d..224ebb4 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -63,9 +63,9 @@ config SAMPLE_RPMSG_CLIENT to communicate with an AMP-configured remote processor over the rpmsg bus. -config SAMPLE_LIVE_PATCHING +config SAMPLE_LIVEPATCH tristate "Build live patching sample -- loadable modules only" - depends on LIVE_PATCHING && m + depends on LIVEPATCH && m help Builds a sample live patch that replaces the procfs handler for /proc/cmdline to print "this has been live patched". diff --git a/samples/livepatch/Makefile b/samples/livepatch/Makefile index 7f1cdc1..10319d7 100644 --- a/samples/livepatch/Makefile +++ b/samples/livepatch/Makefile @@ -1 +1 @@ -obj-$(CONFIG_SAMPLE_LIVE_PATCHING) += livepatch-sample.o +obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch-sample.o -- cgit v1.1