1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
|
/*
* livepatch.h - Kernel Live Patching Core
*
* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
* Copyright (C) 2014 SUSE
*
* 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/>.
*/
#ifndef _LINUX_LIVEPATCH_H_
#define _LINUX_LIVEPATCH_H_
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/completion.h>
#if IS_ENABLED(CONFIG_LIVEPATCH)
#include <asm/livepatch.h>
/* 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
* @stack_node: list node for klp_ops func_stack list
* @old_size: size of the old function
* @new_size: size of the new function
* @kobj_added: @kobj has been added and needs freeing
* @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 stack_node;
unsigned long old_size, new_size;
bool kobj_added;
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
* @mod: kernel module associated with the patched object
* (NULL for vmlinux)
* @kobj_added: @kobj has been added and needs freeing
* @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 module *mod;
bool kobj_added;
bool patched;
};
/**
* struct klp_patch - patch structure for live patching
* @mod: reference to the live patch module
* @objs: object entries for kernel objects to be patched
* @list: list node for global list of actively used patches
* @kobj: kobject for sysfs resources
* @kobj_added: @kobj has been added and needs freeing
* @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;
/* internal */
struct list_head list;
struct kobject kobj;
bool kobj_added;
bool enabled;
bool forced;
struct work_struct free_work;
struct completion finish;
};
#define klp_for_each_object(patch, obj) \
for (obj = patch->objs; obj->funcs || obj->name; obj++)
#define klp_for_each_func(obj, func) \
for (func = obj->funcs; \
func->old_name || func->new_func || func->old_sympos; \
func++)
int klp_enable_patch(struct klp_patch *);
void arch_klp_init_object_loaded(struct klp_patch *patch,
struct klp_object *obj);
/* 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);
#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) {}
#endif /* CONFIG_LIVEPATCH */
#endif /* _LINUX_LIVEPATCH_H_ */
|
