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Livepatching changes for 5.5

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Merge tag 'livepatching-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching

Pull livepatching updates from Petr Mladek:

 - New API to track system state changes done be livepatch callbacks. It
   helps to maintain compatibility between livepatches.

 - Update Kconfig help text. ORC is another reliable unwinder.

 - Disable generic selftest timeout. Livepatch selftests have their own
   per-operation fine-grained timeouts.

* tag 'livepatching-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  x86/stacktrace: update kconfig help text for reliable unwinders
  livepatch: Selftests of the API for tracking system state changes
  livepatch: Documentation of the new API for tracking system state changes
  livepatch: Allow to distinguish different version of system state changes
  livepatch: Basic API to track system state changes
  livepatch: Keep replaced patches until post_patch callback is called
  selftests/livepatch: Disable the timeout
This commit is contained in:
Linus Torvalds 2019-11-25 19:43:48 -08:00
commit f838767555
17 changed files with 902 additions and 25 deletions
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1
Documentation/livepatch/index.rst
View File

@ -12,6 +12,7 @@ Kernel Livepatching
cumulative-patches
module-elf-format
shadow-vars
system-state
.. only:: subproject and html

167
Documentation/livepatch/system-state.rst Normal file
View File

@ -0,0 +1,167 @@
====================
System State Changes
====================
Some users are really reluctant to reboot a system. This brings the need
to provide more livepatches and maintain some compatibility between them.
Maintaining more livepatches is much easier with cumulative livepatches.
Each new livepatch completely replaces any older one. It can keep,
add, and even remove fixes. And it is typically safe to replace any version
of the livepatch with any other one thanks to the atomic replace feature.
The problems might come with shadow variables and callbacks. They might
change the system behavior or state so that it is no longer safe to
go back and use an older livepatch or the original kernel code. Also
any new livepatch must be able to detect what changes have already been
done by the already installed livepatches.
This is where the livepatch system state tracking gets useful. It
allows to:
- store data needed to manipulate and restore the system state
- define compatibility between livepatches using a change id
and version
1. Livepatch system state API
=============================
The state of the system might get modified either by several livepatch callbacks
or by the newly used code. Also it must be possible to find changes done by
already installed livepatches.
Each modified state is described by struct klp_state, see
include/linux/livepatch.h.
Each livepatch defines an array of struct klp_states. They mention
all states that the livepatch modifies.
The livepatch author must define the following two fields for each
struct klp_state:
- *id*
- Non-zero number used to identify the affected system state.
- *version*
- Number describing the variant of the system state change that
is supported by the given livepatch.
The state can be manipulated using two functions:
- *klp_get_state(patch, id)*
- Get struct klp_state associated with the given livepatch
and state id.
- *klp_get_prev_state(id)*
- Get struct klp_state associated with the given feature id and
already installed livepatches.
2. Livepatch compatibility
==========================
The system state version is used to prevent loading incompatible livepatches.
The check is done when the livepatch is enabled. The rules are:
- Any completely new system state modification is allowed.
- System state modifications with the same or higher version are allowed
for already modified system states.
- Cumulative livepatches must handle all system state modifications from
already installed livepatches.
- Non-cumulative livepatches are allowed to touch already modified
system states.
3. Supported scenarios
======================
Livepatches have their life-cycle and the same is true for the system
state changes. Every compatible livepatch has to support the following
scenarios:
- Modify the system state when the livepatch gets enabled and the state
has not been already modified by a livepatches that are being
replaced.
- Take over or update the system state modification when is has already
been done by a livepatch that is being replaced.
- Restore the original state when the livepatch is disabled.
- Restore the previous state when the transition is reverted.
It might be the original system state or the state modification
done by livepatches that were being replaced.
- Remove any already made changes when error occurs and the livepatch
cannot get enabled.
4. Expected usage
=================
System states are usually modified by livepatch callbacks. The expected
role of each callback is as follows:
*pre_patch()*
- Allocate *state->data* when necessary. The allocation might fail
and *pre_patch()* is the only callback that could stop loading
of the livepatch. The allocation is not needed when the data
are already provided by previously installed livepatches.
- Do any other preparatory action that is needed by
the new code even before the transition gets finished.
For example, initialize *state->data*.
The system state itself is typically modified in *post_patch()*
when the entire system is able to handle it.
- Clean up its own mess in case of error. It might be done by a custom
code or by calling *post_unpatch()* explicitly.
*post_patch()*
- Copy *state->data* from the previous livepatch when they are
compatible.
- Do the actual system state modification. Eventually allow
the new code to use it.
- Make sure that *state->data* has all necessary information.
- Free *state->data* from replaces livepatches when they are
not longer needed.
*pre_unpatch()*
- Prevent the code, added by the livepatch, relying on the system
state change.
- Revert the system state modification..
*post_unpatch()*
- Distinguish transition reverse and livepatch disabling by
checking *klp_get_prev_state()*.
- In case of transition reverse, restore the previous system
state. It might mean doing nothing.
- Remove any not longer needed setting or data.
.. note::
*pre_unpatch()* typically does symmetric operations to *post_patch()*.
Except that it is called only when the livepatch is being disabled.
Therefore it does not need to care about any previously installed
livepatch.
*post_unpatch()* typically does symmetric operations to *pre_patch()*.
It might be called also during the transition reverse. Therefore it
has to handle the state of the previously installed livepatches.

4
arch/x86/Kconfig.debug
View File

@ -316,10 +316,6 @@ config UNWINDER_FRAME_POINTER
unwinder, but the kernel text size will grow by ~3% and the kernel's
overall performance will degrade by roughly 5-10%.
This option is recommended if you want to use the livepatch
consistency model, as this is currently the only way to get a
reliable stack trace (CONFIG_HAVE_RELIABLE_STACKTRACE).
config UNWINDER_GUESS
bool "Guess unwinder"
depends on EXPERT

17
include/linux/livepatch.h
View File

@ -130,10 +130,23 @@ struct klp_object {
bool patched;
};
/**
* struct klp_state - state of the system modified by the livepatch
* @id: system state identifier (non-zero)
* @version: version of the change
* @data: custom data
*/
struct klp_state {
unsigned long id;
unsigned int version;
void *data;
};
/**
* struct klp_patch - patch structure for live patching
* @mod: reference to the live patch module
* @objs: object entries for kernel objects to be patched
* @states: system states that can get modified
* @replace: replace all actively used patches
* @list: list node for global list of actively used patches
* @kobj: kobject for sysfs resources
@ -147,6 +160,7 @@ struct klp_patch {
/* external */
struct module *mod;
struct klp_object *objs;
struct klp_state *states;
bool replace;
/* internal */
@ -217,6 +231,9 @@ void *klp_shadow_get_or_alloc(void *obj, unsigned long id,
void klp_shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor);
void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor);
struct klp_state *klp_get_state(struct klp_patch *patch, unsigned long id);
struct klp_state *klp_get_prev_state(unsigned long id);
#else /* !CONFIG_LIVEPATCH */
static inline int klp_module_coming(struct module *mod) { return 0; }

2
kernel/livepatch/Makefile
View File

@ -1,4 +1,4 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_LIVEPATCH) += livepatch.o
livepatch-objs := core.o patch.o shadow.o transition.o
livepatch-objs := core.o patch.o shadow.o state.o transition.o

44
kernel/livepatch/core.c
View File

@ -22,6 +22,7 @@
#include <asm/cacheflush.h>
#include "core.h"
#include "patch.h"
#include "state.h"
#include "transition.h"
/*
@ -632,7 +633,7 @@ static void klp_free_objects_dynamic(struct klp_patch *patch)
* The operation must be completed by calling klp_free_patch_finish()
* outside klp_mutex.
*/
void klp_free_patch_start(struct klp_patch *patch)
static void klp_free_patch_start(struct klp_patch *patch)
{
if (!list_empty(&patch->list))
list_del(&patch->list);
@ -677,6 +678,23 @@ static void klp_free_patch_work_fn(struct work_struct *work)
klp_free_patch_finish(patch);
}
void klp_free_patch_async(struct klp_patch *patch)
{
klp_free_patch_start(patch);
schedule_work(&patch->free_work);
}
void klp_free_replaced_patches_async(struct klp_patch *new_patch)
{
struct klp_patch *old_patch, *tmp_patch;
klp_for_each_patch_safe(old_patch, tmp_patch) {
if (old_patch == new_patch)
return;
klp_free_patch_async(old_patch);
}
}
static int klp_init_func(struct klp_object *obj, struct klp_func *func)
{
if (!func->old_name)
@ -992,6 +1010,13 @@ int klp_enable_patch(struct klp_patch *patch)
mutex_lock(&klp_mutex);
if (!klp_is_patch_compatible(patch)) {
pr_err("Livepatch patch (%s) is not compatible with the already installed livepatches.\n",
patch->mod->name);
mutex_unlock(&klp_mutex);
return -EINVAL;
}
ret = klp_init_patch_early(patch);
if (ret) {
mutex_unlock(&klp_mutex);
@ -1022,12 +1047,13 @@ err:
EXPORT_SYMBOL_GPL(klp_enable_patch);
/*
* This function removes replaced patches.
* This function unpatches objects from the replaced livepatches.
*
* We could be pretty aggressive here. It is called in the situation where
* these structures are no longer accessible. All functions are redirected
* by the klp_transition_patch. They use either a new code or they are in
* the original code because of the special nop function patches.
* these structures are no longer accessed from the ftrace handler.
* All functions are redirected by the klp_transition_patch. They
* use either a new code or they are in the original code because
* of the special nop function patches.
*
* The only exception is when the transition was forced. In this case,
* klp_ftrace_handler() might still see the replaced patch on the stack.
@ -1035,18 +1061,16 @@ EXPORT_SYMBOL_GPL(klp_enable_patch);
* thanks to RCU. We only have to keep the patches on the system. Also
* this is handled transparently by patch->module_put.
*/
void klp_discard_replaced_patches(struct klp_patch *new_patch)
void klp_unpatch_replaced_patches(struct klp_patch *new_patch)
{
struct klp_patch *old_patch, *tmp_patch;
struct klp_patch *old_patch;
klp_for_each_patch_safe(old_patch, tmp_patch) {
klp_for_each_patch(old_patch) {
if (old_patch == new_patch)
return;
old_patch->enabled = false;
klp_unpatch_objects(old_patch);
klp_free_patch_start(old_patch);
schedule_work(&old_patch->free_work);
}
}

5
kernel/livepatch/core.h
View File

@ -13,8 +13,9 @@ extern struct list_head klp_patches;
#define klp_for_each_patch(patch) \
list_for_each_entry(patch, &klp_patches, list)
void klp_free_patch_start(struct klp_patch *patch);
void klp_discard_replaced_patches(struct klp_patch *new_patch);
void klp_free_patch_async(struct klp_patch *patch);
void klp_free_replaced_patches_async(struct klp_patch *new_patch);
void klp_unpatch_replaced_patches(struct klp_patch *new_patch);
void klp_discard_nops(struct klp_patch *new_patch);
static inline bool klp_is_object_loaded(struct klp_object *obj)

119
kernel/livepatch/state.c Normal file
View File

@ -0,0 +1,119 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* system_state.c - State of the system modified by livepatches
*
* Copyright (C) 2019 SUSE
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/livepatch.h>
#include "core.h"
#include "state.h"
#include "transition.h"
#define klp_for_each_state(patch, state) \
for (state = patch->states; state && state->id; state++)
/**
* klp_get_state() - get information about system state modified by
* the given patch
* @patch: livepatch that modifies the given system state
* @id: custom identifier of the modified system state
*
* Checks whether the given patch modifies the given system state.
*
* The function can be called either from pre/post (un)patch
* callbacks or from the kernel code added by the livepatch.
*
* Return: pointer to struct klp_state when found, otherwise NULL.
*/
struct klp_state *klp_get_state(struct klp_patch *patch, unsigned long id)
{
struct klp_state *state;
klp_for_each_state(patch, state) {
if (state->id == id)
return state;
}
return NULL;
}
EXPORT_SYMBOL_GPL(klp_get_state);
/**
* klp_get_prev_state() - get information about system state modified by
* the already installed livepatches
* @id: custom identifier of the modified system state
*
* Checks whether already installed livepatches modify the given
* system state.
*
* The same system state can be modified by more non-cumulative
* livepatches. It is expected that the latest livepatch has
* the most up-to-date information.
*
* The function can be called only during transition when a new
* livepatch is being enabled or when such a transition is reverted.
* It is typically called only from from pre/post (un)patch
* callbacks.
*
* Return: pointer to the latest struct klp_state from already
* installed livepatches, NULL when not found.
*/
struct klp_state *klp_get_prev_state(unsigned long id)
{
struct klp_patch *patch;
struct klp_state *state, *last_state = NULL;
if (WARN_ON_ONCE(!klp_transition_patch))
return NULL;
klp_for_each_patch(patch) {
if (patch == klp_transition_patch)
goto out;
state = klp_get_state(patch, id);
if (state)
last_state = state;
}
out:
return last_state;
}
EXPORT_SYMBOL_GPL(klp_get_prev_state);
/* Check if the patch is able to deal with the existing system state. */
static bool klp_is_state_compatible(struct klp_patch *patch,
struct klp_state *old_state)
{
struct klp_state *state;
state = klp_get_state(patch, old_state->id);
/* A cumulative livepatch must handle all already modified states. */
if (!state)
return !patch->replace;
return state->version >= old_state->version;
}
/*
* Check that the new livepatch will not break the existing system states.
* Cumulative patches must handle all already modified states.
* Non-cumulative patches can touch already modified states.
*/
bool klp_is_patch_compatible(struct klp_patch *patch)
{
struct klp_patch *old_patch;
struct klp_state *old_state;
klp_for_each_patch(old_patch) {
klp_for_each_state(old_patch, old_state) {
if (!klp_is_state_compatible(patch, old_state))
return false;
}
}
return true;
}

9
kernel/livepatch/state.h Normal file
View File

@ -0,0 +1,9 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LIVEPATCH_STATE_H
#define _LIVEPATCH_STATE_H
#include <linux/livepatch.h>
bool klp_is_patch_compatible(struct klp_patch *patch);
#endif /* _LIVEPATCH_STATE_H */

12
kernel/livepatch/transition.c
View File

@ -78,7 +78,7 @@ static void klp_complete_transition(void)
klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
if (klp_transition_patch->replace && klp_target_state == KLP_PATCHED) {
klp_discard_replaced_patches(klp_transition_patch);
klp_unpatch_replaced_patches(klp_transition_patch);
klp_discard_nops(klp_transition_patch);
}
@ -446,14 +446,14 @@ void klp_try_complete_transition(void)
klp_complete_transition();
/*
* It would make more sense to free the patch in
* It would make more sense to free the unused patches in
* klp_complete_transition() but it is called also
* from klp_cancel_transition().
*/
if (!patch->enabled) {
klp_free_patch_start(patch);
schedule_work(&patch->free_work);
}
if (!patch->enabled)
klp_free_patch_async(patch);
else if (patch->replace)
klp_free_replaced_patches_async(patch);
}
/*

5
lib/livepatch/Makefile
View File

@ -8,7 +8,10 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \
test_klp_callbacks_busy.o \
test_klp_callbacks_mod.o \
test_klp_livepatch.o \
test_klp_shadow_vars.o
test_klp_shadow_vars.o \
test_klp_state.o \
test_klp_state2.o \
test_klp_state3.o
# Target modules to be livepatched require CC_FLAGS_FTRACE
CFLAGS_test_klp_callbacks_busy.o += $(CC_FLAGS_FTRACE)

162
lib/livepatch/test_klp_state.c Normal file
View File

@ -0,0 +1,162 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2019 SUSE
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/livepatch.h>
#define CONSOLE_LOGLEVEL_STATE 1
/* Version 1 does not support migration. */
#define CONSOLE_LOGLEVEL_STATE_VERSION 1
static const char *const module_state[] = {
[MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state",
[MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init",
[MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away",
[MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up",
};
static void callback_info(const char *callback, struct klp_object *obj)
{
if (obj->mod)
pr_info("%s: %s -> %s\n", callback, obj->mod->name,
module_state[obj->mod->state]);
else
pr_info("%s: vmlinux\n", callback);
}
static struct klp_patch patch;
static int allocate_loglevel_state(void)
{
struct klp_state *loglevel_state;
loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
if (!loglevel_state)
return -EINVAL;
loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL);
if (!loglevel_state->data)
return -ENOMEM;
pr_info("%s: allocating space to store console_loglevel\n",
__func__);
return 0;
}
static void fix_console_loglevel(void)
{
struct klp_state *loglevel_state;
loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
if (!loglevel_state)
return;
pr_info("%s: fixing console_loglevel\n", __func__);
*(int *)loglevel_state->data = console_loglevel;
console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
}
static void restore_console_loglevel(void)
{
struct klp_state *loglevel_state;
loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
if (!loglevel_state)
return;
pr_info("%s: restoring console_loglevel\n", __func__);
console_loglevel = *(int *)loglevel_state->data;
}
static void free_loglevel_state(void)
{
struct klp_state *loglevel_state;
loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
if (!loglevel_state)
return;
pr_info("%s: freeing space for the stored console_loglevel\n",
__func__);
kfree(loglevel_state->data);
}
/* Executed on object patching (ie, patch enablement) */
static int pre_patch_callback(struct klp_object *obj)
{
callback_info(__func__, obj);
return allocate_loglevel_state();
}
/* Executed on object unpatching (ie, patch disablement) */
static void post_patch_callback(struct klp_object *obj)
{
callback_info(__func__, obj);
fix_console_loglevel();
}
/* Executed on object unpatching (ie, patch disablement) */
static void pre_unpatch_callback(struct klp_object *obj)
{
callback_info(__func__, obj);
restore_console_loglevel();
}
/* Executed on object unpatching (ie, patch disablement) */
static void post_unpatch_callback(struct klp_object *obj)
{
callback_info(__func__, obj);
free_loglevel_state();
}
static struct klp_func no_funcs[] = {
{}
};
static struct klp_object objs[] = {
{
.name = NULL, /* vmlinux */
.funcs = no_funcs,
.callbacks = {
.pre_patch = pre_patch_callback,
.post_patch = post_patch_callback,
.pre_unpatch = pre_unpatch_callback,
.post_unpatch = post_unpatch_callback,
},
}, { }
};
static struct klp_state states[] = {
{
.id = CONSOLE_LOGLEVEL_STATE,
.version = CONSOLE_LOGLEVEL_STATE_VERSION,
}, { }
};
static struct klp_patch patch = {
.mod = THIS_MODULE,
.objs = objs,
.states = states,
.replace = true,
};
static int test_klp_callbacks_demo_init(void)
{
return klp_enable_patch(&patch);
}
static void test_klp_callbacks_demo_exit(void)
{
}
module_init(test_klp_callbacks_demo_init);
module_exit(test_klp_callbacks_demo_exit);
MODULE_LICENSE("GPL");
MODULE_INFO(livepatch, "Y");
MODULE_AUTHOR("Petr Mladek <pmladek@suse.com>");
MODULE_DESCRIPTION("Livepatch test: system state modification");

191
lib/livepatch/test_klp_state2.c Normal file
View File

@ -0,0 +1,191 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2019 SUSE
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/livepatch.h>
#define CONSOLE_LOGLEVEL_STATE 1
/* Version 2 supports migration. */
#define CONSOLE_LOGLEVEL_STATE_VERSION 2
static const char *const module_state[] = {
[MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state",
[MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init",
[MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away",
[MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up",
};
static void callback_info(const char *callback, struct klp_object *obj)
{
if (obj->mod)
pr_info("%s: %s -> %s\n", callback, obj->mod->name,
module_state[obj->mod->state]);
else
pr_info("%s: vmlinux\n", callback);
}
static struct klp_patch patch;
static int allocate_loglevel_state(void)
{
struct klp_state *loglevel_state, *prev_loglevel_state;
prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);
if (prev_loglevel_state) {
pr_info("%s: space to store console_loglevel already allocated\n",
__func__);
return 0;
}
loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
if (!loglevel_state)
return -EINVAL;
loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL);
if (!loglevel_state->data)
return -ENOMEM;
pr_info("%s: allocating space to store console_loglevel\n",
__func__);
return 0;
}
static void fix_console_loglevel(void)
{
struct klp_state *loglevel_state, *prev_loglevel_state;
loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
if (!loglevel_state)
return;
prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);
if (prev_loglevel_state) {
pr_info("%s: taking over the console_loglevel change\n",
__func__);
loglevel_state->data = prev_loglevel_state->data;
return;
}
pr_info("%s: fixing console_loglevel\n", __func__);
*(int *)loglevel_state->data = console_loglevel;
console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
}
static void restore_console_loglevel(void)
{
struct klp_state *loglevel_state, *prev_loglevel_state;
prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);
if (prev_loglevel_state) {
pr_info("%s: passing the console_loglevel change back to the old livepatch\n",
__func__);
return;
}
loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
if (!loglevel_state)
return;
pr_info("%s: restoring console_loglevel\n", __func__);
console_loglevel = *(int *)loglevel_state->data;
}
static void free_loglevel_state(void)
{
struct klp_state *loglevel_state, *prev_loglevel_state;
prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);
if (prev_loglevel_state) {
pr_info("%s: keeping space to store console_loglevel\n",
__func__);
return;
}
loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
if (!loglevel_state)
return;
pr_info("%s: freeing space for the stored console_loglevel\n",
__func__);
kfree(loglevel_state->data);
}
/* Executed on object patching (ie, patch enablement) */
static int pre_patch_callback(struct klp_object *obj)
{
callback_info(__func__, obj);
return allocate_loglevel_state();
}
/* Executed on object unpatching (ie, patch disablement) */
static void post_patch_callback(struct klp_object *obj)
{
callback_info(__func__, obj);
fix_console_loglevel();
}
/* Executed on object unpatching (ie, patch disablement) */
static void pre_unpatch_callback(struct klp_object *obj)
{
callback_info(__func__, obj);
restore_console_loglevel();
}
/* Executed on object unpatching (ie, patch disablement) */
static void post_unpatch_callback(struct klp_object *obj)
{
callback_info(__func__, obj);
free_loglevel_state();
}
static struct klp_func no_funcs[] = {
{}
};
static struct klp_object objs[] = {
{
.name = NULL, /* vmlinux */
.funcs = no_funcs,
.callbacks = {
.pre_patch = pre_patch_callback,
.post_patch = post_patch_callback,
.pre_unpatch = pre_unpatch_callback,
.post_unpatch = post_unpatch_callback,
},
}, { }
};
static struct klp_state states[] = {
{
.id = CONSOLE_LOGLEVEL_STATE,
.version = CONSOLE_LOGLEVEL_STATE_VERSION,
}, { }
};
static struct klp_patch patch = {
.mod = THIS_MODULE,
.objs = objs,
.states = states,
.replace = true,
};
static int test_klp_callbacks_demo_init(void)
{
return klp_enable_patch(&patch);
}
static void test_klp_callbacks_demo_exit(void)
{
}
module_init(test_klp_callbacks_demo_init);
module_exit(test_klp_callbacks_demo_exit);
MODULE_LICENSE("GPL");
MODULE_INFO(livepatch, "Y");
MODULE_AUTHOR("Petr Mladek <pmladek@suse.com>");
MODULE_DESCRIPTION("Livepatch test: system state modification");

5
lib/livepatch/test_klp_state3.c Normal file
View File

@ -0,0 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2019 SUSE
/* The console loglevel fix is the same in the next cumulative patch. */
#include "test_klp_state2.c"

3
tools/testing/selftests/livepatch/Makefile
View File

@ -4,6 +4,7 @@ TEST_PROGS_EXTENDED := functions.sh
TEST_PROGS := \
test-livepatch.sh \
test-callbacks.sh \
test-shadow-vars.sh
test-shadow-vars.sh \
test-state.sh
include ../lib.mk

1
tools/testing/selftests/livepatch/settings Normal file
View File

@ -0,0 +1 @@
timeout=0

180
tools/testing/selftests/livepatch/test-state.sh Executable file
View File

@ -0,0 +1,180 @@
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2019 SUSE
. $(dirname $0)/functions.sh
MOD_LIVEPATCH=test_klp_state
MOD_LIVEPATCH2=test_klp_state2
MOD_LIVEPATCH3=test_klp_state3
set_dynamic_debug
# TEST: Loading and removing a module that modifies the system state
echo -n "TEST: system state modification ... "
dmesg -C
load_lp $MOD_LIVEPATCH
disable_lp $MOD_LIVEPATCH
unload_lp $MOD_LIVEPATCH
check_result "% modprobe $MOD_LIVEPATCH
livepatch: enabling patch '$MOD_LIVEPATCH'
livepatch: '$MOD_LIVEPATCH': initializing patching transition
$MOD_LIVEPATCH: pre_patch_callback: vmlinux
$MOD_LIVEPATCH: allocate_loglevel_state: allocating space to store console_loglevel
livepatch: '$MOD_LIVEPATCH': starting patching transition
livepatch: '$MOD_LIVEPATCH': completing patching transition
$MOD_LIVEPATCH: post_patch_callback: vmlinux
$MOD_LIVEPATCH: fix_console_loglevel: fixing console_loglevel
livepatch: '$MOD_LIVEPATCH': patching complete
% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
$MOD_LIVEPATCH: restore_console_loglevel: restoring console_loglevel
livepatch: '$MOD_LIVEPATCH': starting unpatching transition
livepatch: '$MOD_LIVEPATCH': completing unpatching transition
$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
$MOD_LIVEPATCH: free_loglevel_state: freeing space for the stored console_loglevel
livepatch: '$MOD_LIVEPATCH': unpatching complete
% rmmod $MOD_LIVEPATCH"
# TEST: Take over system state change by a cumulative patch
echo -n "TEST: taking over system state modification ... "
dmesg -C
load_lp $MOD_LIVEPATCH
load_lp $MOD_LIVEPATCH2
unload_lp $MOD_LIVEPATCH
disable_lp $MOD_LIVEPATCH2
unload_lp $MOD_LIVEPATCH2
check_result "% modprobe $MOD_LIVEPATCH
livepatch: enabling patch '$MOD_LIVEPATCH'
livepatch: '$MOD_LIVEPATCH': initializing patching transition
$MOD_LIVEPATCH: pre_patch_callback: vmlinux
$MOD_LIVEPATCH: allocate_loglevel_state: allocating space to store console_loglevel
livepatch: '$MOD_LIVEPATCH': starting patching transition
livepatch: '$MOD_LIVEPATCH': completing patching transition
$MOD_LIVEPATCH: post_patch_callback: vmlinux
$MOD_LIVEPATCH: fix_console_loglevel: fixing console_loglevel
livepatch: '$MOD_LIVEPATCH': patching complete
% modprobe $MOD_LIVEPATCH2
livepatch: enabling patch '$MOD_LIVEPATCH2'
livepatch: '$MOD_LIVEPATCH2': initializing patching transition
$MOD_LIVEPATCH2: pre_patch_callback: vmlinux
$MOD_LIVEPATCH2: allocate_loglevel_state: space to store console_loglevel already allocated
livepatch: '$MOD_LIVEPATCH2': starting patching transition
livepatch: '$MOD_LIVEPATCH2': completing patching transition
$MOD_LIVEPATCH2: post_patch_callback: vmlinux
$MOD_LIVEPATCH2: fix_console_loglevel: taking over the console_loglevel change
livepatch: '$MOD_LIVEPATCH2': patching complete
% rmmod $MOD_LIVEPATCH
% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
$MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
$MOD_LIVEPATCH2: restore_console_loglevel: restoring console_loglevel
livepatch: '$MOD_LIVEPATCH2': starting unpatching transition
livepatch: '$MOD_LIVEPATCH2': completing unpatching transition
$MOD_LIVEPATCH2: post_unpatch_callback: vmlinux
$MOD_LIVEPATCH2: free_loglevel_state: freeing space for the stored console_loglevel
livepatch: '$MOD_LIVEPATCH2': unpatching complete
% rmmod $MOD_LIVEPATCH2"
# TEST: Take over system state change by a cumulative patch
echo -n "TEST: compatible cumulative livepatches ... "
dmesg -C
load_lp $MOD_LIVEPATCH2
load_lp $MOD_LIVEPATCH3
unload_lp $MOD_LIVEPATCH2
load_lp $MOD_LIVEPATCH2
disable_lp $MOD_LIVEPATCH2
unload_lp $MOD_LIVEPATCH2
unload_lp $MOD_LIVEPATCH3
check_result "% modprobe $MOD_LIVEPATCH2
livepatch: enabling patch '$MOD_LIVEPATCH2'
livepatch: '$MOD_LIVEPATCH2': initializing patching transition
$MOD_LIVEPATCH2: pre_patch_callback: vmlinux
$MOD_LIVEPATCH2: allocate_loglevel_state: allocating space to store console_loglevel
livepatch: '$MOD_LIVEPATCH2': starting patching transition
livepatch: '$MOD_LIVEPATCH2': completing patching transition
$MOD_LIVEPATCH2: post_patch_callback: vmlinux
$MOD_LIVEPATCH2: fix_console_loglevel: fixing console_loglevel
livepatch: '$MOD_LIVEPATCH2': patching complete
% modprobe $MOD_LIVEPATCH3
livepatch: enabling patch '$MOD_LIVEPATCH3'
livepatch: '$MOD_LIVEPATCH3': initializing patching transition
$MOD_LIVEPATCH3: pre_patch_callback: vmlinux
$MOD_LIVEPATCH3: allocate_loglevel_state: space to store console_loglevel already allocated
livepatch: '$MOD_LIVEPATCH3': starting patching transition
livepatch: '$MOD_LIVEPATCH3': completing patching transition
$MOD_LIVEPATCH3: post_patch_callback: vmlinux
$MOD_LIVEPATCH3: fix_console_loglevel: taking over the console_loglevel change
livepatch: '$MOD_LIVEPATCH3': patching complete
% rmmod $MOD_LIVEPATCH2
% modprobe $MOD_LIVEPATCH2
livepatch: enabling patch '$MOD_LIVEPATCH2'
livepatch: '$MOD_LIVEPATCH2': initializing patching transition
$MOD_LIVEPATCH2: pre_patch_callback: vmlinux
$MOD_LIVEPATCH2: allocate_loglevel_state: space to store console_loglevel already allocated
livepatch: '$MOD_LIVEPATCH2': starting patching transition
livepatch: '$MOD_LIVEPATCH2': completing patching transition
$MOD_LIVEPATCH2: post_patch_callback: vmlinux
$MOD_LIVEPATCH2: fix_console_loglevel: taking over the console_loglevel change
livepatch: '$MOD_LIVEPATCH2': patching complete
% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
$MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
$MOD_LIVEPATCH2: restore_console_loglevel: restoring console_loglevel
livepatch: '$MOD_LIVEPATCH2': starting unpatching transition
livepatch: '$MOD_LIVEPATCH2': completing unpatching transition
$MOD_LIVEPATCH2: post_unpatch_callback: vmlinux
$MOD_LIVEPATCH2: free_loglevel_state: freeing space for the stored console_loglevel
livepatch: '$MOD_LIVEPATCH2': unpatching complete
% rmmod $MOD_LIVEPATCH2
% rmmod $MOD_LIVEPATCH3"
# TEST: Failure caused by incompatible cumulative livepatches
echo -n "TEST: incompatible cumulative livepatches ... "
dmesg -C
load_lp $MOD_LIVEPATCH2
load_failing_mod $MOD_LIVEPATCH
disable_lp $MOD_LIVEPATCH2
unload_lp $MOD_LIVEPATCH2
check_result "% modprobe $MOD_LIVEPATCH2
livepatch: enabling patch '$MOD_LIVEPATCH2'
livepatch: '$MOD_LIVEPATCH2': initializing patching transition
$MOD_LIVEPATCH2: pre_patch_callback: vmlinux
$MOD_LIVEPATCH2: allocate_loglevel_state: allocating space to store console_loglevel
livepatch: '$MOD_LIVEPATCH2': starting patching transition
livepatch: '$MOD_LIVEPATCH2': completing patching transition
$MOD_LIVEPATCH2: post_patch_callback: vmlinux
$MOD_LIVEPATCH2: fix_console_loglevel: fixing console_loglevel
livepatch: '$MOD_LIVEPATCH2': patching complete
% modprobe $MOD_LIVEPATCH
livepatch: Livepatch patch ($MOD_LIVEPATCH) is not compatible with the already installed livepatches.
modprobe: ERROR: could not insert '$MOD_LIVEPATCH': Invalid argument
% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
$MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
$MOD_LIVEPATCH2: restore_console_loglevel: restoring console_loglevel
livepatch: '$MOD_LIVEPATCH2': starting unpatching transition
livepatch: '$MOD_LIVEPATCH2': completing unpatching transition
$MOD_LIVEPATCH2: post_unpatch_callback: vmlinux
$MOD_LIVEPATCH2: free_loglevel_state: freeing space for the stored console_loglevel
livepatch: '$MOD_LIVEPATCH2': unpatching complete
% rmmod $MOD_LIVEPATCH2"
exit 0