258 lines
8.2 KiB
C
258 lines
8.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/*
|
|
* livepatch.h - Kernel Live Patching Core
|
|
*
|
|
* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
|
|
* Copyright (C) 2014 SUSE
|
|
*/
|
|
|
|
#ifndef _LINUX_LIVEPATCH_H_
|
|
#define _LINUX_LIVEPATCH_H_
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/ftrace.h>
|
|
#include <linux/completion.h>
|
|
#include <linux/list.h>
|
|
#include <linux/livepatch_sched.h>
|
|
|
|
#if IS_ENABLED(CONFIG_LIVEPATCH)
|
|
|
|
/* task patch states */
|
|
#define KLP_UNDEFINED -1
|
|
#define KLP_UNPATCHED 0
|
|
#define KLP_PATCHED 1
|
|
|
|
/**
|
|
* struct klp_func - function structure for live patching
|
|
* @old_name: name of the function to be patched
|
|
* @new_func: pointer to the patched function code
|
|
* @old_sympos: a hint indicating which symbol position the old function
|
|
* can be found (optional)
|
|
* @old_func: pointer to the function being patched
|
|
* @kobj: kobject for sysfs resources
|
|
* @node: list node for klp_object func_list
|
|
* @stack_node: list node for klp_ops func_stack list
|
|
* @old_size: size of the old function
|
|
* @new_size: size of the new function
|
|
* @nop: temporary patch to use the original code again; dyn. allocated
|
|
* @patched: the func has been added to the klp_ops list
|
|
* @transition: the func is currently being applied or reverted
|
|
*
|
|
* The patched and transition variables define the func's patching state. When
|
|
* patching, a func is always in one of the following states:
|
|
*
|
|
* patched=0 transition=0: unpatched
|
|
* patched=0 transition=1: unpatched, temporary starting state
|
|
* patched=1 transition=1: patched, may be visible to some tasks
|
|
* patched=1 transition=0: patched, visible to all tasks
|
|
*
|
|
* And when unpatching, it goes in the reverse order:
|
|
*
|
|
* patched=1 transition=0: patched, visible to all tasks
|
|
* patched=1 transition=1: patched, may be visible to some tasks
|
|
* patched=0 transition=1: unpatched, temporary ending state
|
|
* patched=0 transition=0: unpatched
|
|
*/
|
|
struct klp_func {
|
|
/* external */
|
|
const char *old_name;
|
|
void *new_func;
|
|
/*
|
|
* The old_sympos field is optional and can be used to resolve
|
|
* duplicate symbol names in livepatch objects. If this field is zero,
|
|
* it is expected the symbol is unique, otherwise patching fails. If
|
|
* this value is greater than zero then that occurrence of the symbol
|
|
* in kallsyms for the given object is used.
|
|
*/
|
|
unsigned long old_sympos;
|
|
|
|
/* internal */
|
|
void *old_func;
|
|
struct kobject kobj;
|
|
struct list_head node;
|
|
struct list_head stack_node;
|
|
unsigned long old_size, new_size;
|
|
bool nop;
|
|
bool patched;
|
|
bool transition;
|
|
};
|
|
|
|
struct klp_object;
|
|
|
|
/**
|
|
* struct klp_callbacks - pre/post live-(un)patch callback structure
|
|
* @pre_patch: executed before code patching
|
|
* @post_patch: executed after code patching
|
|
* @pre_unpatch: executed before code unpatching
|
|
* @post_unpatch: executed after code unpatching
|
|
* @post_unpatch_enabled: flag indicating if post-unpatch callback
|
|
* should run
|
|
*
|
|
* All callbacks are optional. Only the pre-patch callback, if provided,
|
|
* will be unconditionally executed. If the parent klp_object fails to
|
|
* patch for any reason, including a non-zero error status returned from
|
|
* the pre-patch callback, no further callbacks will be executed.
|
|
*/
|
|
struct klp_callbacks {
|
|
int (*pre_patch)(struct klp_object *obj);
|
|
void (*post_patch)(struct klp_object *obj);
|
|
void (*pre_unpatch)(struct klp_object *obj);
|
|
void (*post_unpatch)(struct klp_object *obj);
|
|
bool post_unpatch_enabled;
|
|
};
|
|
|
|
/**
|
|
* struct klp_object - kernel object structure for live patching
|
|
* @name: module name (or NULL for vmlinux)
|
|
* @funcs: function entries for functions to be patched in the object
|
|
* @callbacks: functions to be executed pre/post (un)patching
|
|
* @kobj: kobject for sysfs resources
|
|
* @func_list: dynamic list of the function entries
|
|
* @node: list node for klp_patch obj_list
|
|
* @mod: kernel module associated with the patched object
|
|
* (NULL for vmlinux)
|
|
* @dynamic: temporary object for nop functions; dynamically allocated
|
|
* @patched: the object's funcs have been added to the klp_ops list
|
|
*/
|
|
struct klp_object {
|
|
/* external */
|
|
const char *name;
|
|
struct klp_func *funcs;
|
|
struct klp_callbacks callbacks;
|
|
|
|
/* internal */
|
|
struct kobject kobj;
|
|
struct list_head func_list;
|
|
struct list_head node;
|
|
struct module *mod;
|
|
bool dynamic;
|
|
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
|
|
* @obj_list: dynamic list of the object entries
|
|
* @enabled: the patch is enabled (but operation may be incomplete)
|
|
* @forced: was involved in a forced transition
|
|
* @free_work: patch cleanup from workqueue-context
|
|
* @finish: for waiting till it is safe to remove the patch module
|
|
*/
|
|
struct klp_patch {
|
|
/* external */
|
|
struct module *mod;
|
|
struct klp_object *objs;
|
|
struct klp_state *states;
|
|
bool replace;
|
|
|
|
/* internal */
|
|
struct list_head list;
|
|
struct kobject kobj;
|
|
struct list_head obj_list;
|
|
bool enabled;
|
|
bool forced;
|
|
struct work_struct free_work;
|
|
struct completion finish;
|
|
};
|
|
|
|
#define klp_for_each_object_static(patch, obj) \
|
|
for (obj = patch->objs; obj->funcs || obj->name; obj++)
|
|
|
|
#define klp_for_each_object_safe(patch, obj, tmp_obj) \
|
|
list_for_each_entry_safe(obj, tmp_obj, &patch->obj_list, node)
|
|
|
|
#define klp_for_each_object(patch, obj) \
|
|
list_for_each_entry(obj, &patch->obj_list, node)
|
|
|
|
#define klp_for_each_func_static(obj, func) \
|
|
for (func = obj->funcs; \
|
|
func->old_name || func->new_func || func->old_sympos; \
|
|
func++)
|
|
|
|
#define klp_for_each_func_safe(obj, func, tmp_func) \
|
|
list_for_each_entry_safe(func, tmp_func, &obj->func_list, node)
|
|
|
|
#define klp_for_each_func(obj, func) \
|
|
list_for_each_entry(func, &obj->func_list, node)
|
|
|
|
int klp_enable_patch(struct klp_patch *);
|
|
|
|
/* Called from the module loader during module coming/going states */
|
|
int klp_module_coming(struct module *mod);
|
|
void klp_module_going(struct module *mod);
|
|
|
|
void klp_copy_process(struct task_struct *child);
|
|
void klp_update_patch_state(struct task_struct *task);
|
|
|
|
static inline bool klp_patch_pending(struct task_struct *task)
|
|
{
|
|
return test_tsk_thread_flag(task, TIF_PATCH_PENDING);
|
|
}
|
|
|
|
static inline bool klp_have_reliable_stack(void)
|
|
{
|
|
return IS_ENABLED(CONFIG_STACKTRACE) &&
|
|
IS_ENABLED(CONFIG_HAVE_RELIABLE_STACKTRACE);
|
|
}
|
|
|
|
typedef int (*klp_shadow_ctor_t)(void *obj,
|
|
void *shadow_data,
|
|
void *ctor_data);
|
|
typedef void (*klp_shadow_dtor_t)(void *obj, void *shadow_data);
|
|
|
|
void *klp_shadow_get(void *obj, unsigned long id);
|
|
void *klp_shadow_alloc(void *obj, unsigned long id,
|
|
size_t size, gfp_t gfp_flags,
|
|
klp_shadow_ctor_t ctor, void *ctor_data);
|
|
void *klp_shadow_get_or_alloc(void *obj, unsigned long id,
|
|
size_t size, gfp_t gfp_flags,
|
|
klp_shadow_ctor_t ctor, void *ctor_data);
|
|
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);
|
|
|
|
int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
|
|
const char *shstrtab, const char *strtab,
|
|
unsigned int symindex, unsigned int secindex,
|
|
const char *objname);
|
|
|
|
#else /* !CONFIG_LIVEPATCH */
|
|
|
|
static inline int klp_module_coming(struct module *mod) { return 0; }
|
|
static inline void klp_module_going(struct module *mod) {}
|
|
static inline bool klp_patch_pending(struct task_struct *task) { return false; }
|
|
static inline void klp_update_patch_state(struct task_struct *task) {}
|
|
static inline void klp_copy_process(struct task_struct *child) {}
|
|
|
|
static inline
|
|
int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
|
|
const char *shstrtab, const char *strtab,
|
|
unsigned int symindex, unsigned int secindex,
|
|
const char *objname)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_LIVEPATCH */
|
|
|
|
#endif /* _LINUX_LIVEPATCH_H_ */
|