| 1 | |
| 2 | * livepatch.h - Kernel Live Patching Core
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| 3 | *
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| 4 | * Copyright (C) 2014 Seth Jennings <[email protected]>
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| 5 | * Copyright (C) 2014 SUSE
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| 6 | *
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| 7 | * This program is free software; you can redistribute it and/or
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| 8 | * modify it under the terms of the GNU General Public License
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| 9 | * as published by the Free Software Foundation; either version 2
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| 10 | * of the License, or (at your option) any later version.
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| 11 | *
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| 12 | * This program is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with this program; if not, see <http://www.gnu.org/licenses/>.
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| 19 |
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| 20 |
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| 21 | #ifndef _LINUX_LIVEPATCH_H_
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| 22 | #define _LINUX_LIVEPATCH_H_
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| 23 |
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| 24 | #include <linux/module.h>
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| 25 | #include <linux/ftrace.h>
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| 26 |
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| 27 | #if IS_ENABLED(CONFIG_LIVEPATCH)
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| 28 |
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| 29 | #include <asm/livepatch.h>
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| 30 |
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| 31 | enum klp_state {
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| 32 | KLP_DISABLED,
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| 33 | KLP_ENABLED
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| 34 | };
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| 35 |
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| 36 | |
| 37 | * struct klp_func - function structure for live patching
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| 38 | * @old_name: name of the function to be patched
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| 39 | * @new_func: pointer to the patched function code
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| 40 | * @old_sympos: a hint indicating which symbol position the old function
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| 41 | * can be found (optional)
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| 42 | * @old_addr: the address of the function being patched
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| 43 | * @kobj: kobject for sysfs resources
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| 44 | * @state: tracks function-level patch application state
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| 45 | * @stack_node: list node for klp_ops func_stack list
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| 46 |
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| 47 | struct klp_func {
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| 48 |
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| 49 | const char *old_name;
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| 50 | void *new_func;
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| 51 | |
| 52 | * The old_sympos field is optional and can be used to resolve
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| 53 | * duplicate symbol names in livepatch objects. If this field is zero,
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| 54 | * it is expected the symbol is unique, otherwise patching fails. If
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| 55 | * this value is greater than zero then that occurrence of the symbol
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| 56 | * in kallsyms for the given object is used.
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| 57 |
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| 58 | unsigned long old_sympos;
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| 59 |
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| 60 |
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| 61 | unsigned long old_addr;
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| 62 | struct kobject kobj;
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| 63 | enum klp_state state;
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| 64 | struct list_head stack_node;
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| 65 | };
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| 66 |
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| 67 | |
| 68 | * struct klp_object - kernel object structure for live patching
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| 69 | * @name: module name (or NULL for vmlinux)
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| 70 | * @funcs: function entries for functions to be patched in the object
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| 71 | * @kobj: kobject for sysfs resources
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| 72 | * @mod: kernel module associated with the patched object
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| 73 | * (NULL for vmlinux)
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| 74 | * @state: tracks object-level patch application state
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| 75 |
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| 76 | struct klp_object {
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| 77 |
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| 78 | const char *name;
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| 79 | struct klp_func *funcs;
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| 80 |
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| 81 |
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| 82 | struct kobject kobj;
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| 83 | struct module *mod;
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| 84 | enum klp_state state;
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| 85 | };
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| 86 |
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| 87 | |
| 88 | * struct klp_patch - patch structure for live patching
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| 89 | * @mod: reference to the live patch module
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| 90 | * @objs: object entries for kernel objects to be patched
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| 91 | * @list: list node for global list of registered patches
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| 92 | * @kobj: kobject for sysfs resources
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| 93 | * @state: tracks patch-level application state
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| 94 |
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| 95 | struct klp_patch {
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| 96 |
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| 97 | struct module *mod;
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| 98 | struct klp_object *objs;
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| 99 |
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| 100 |
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| 101 | struct list_head list;
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| 102 | struct kobject kobj;
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| 103 | enum klp_state state;
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| 104 | };
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| 105 |
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| 106 | #define klp_for_each_object(patch, obj) \
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| 107 | for (obj = patch->objs; obj->funcs || obj->name; obj++)
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| 108 |
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| 109 | #define klp_for_each_func(obj, func) \
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| 110 | for (func = obj->funcs; \
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| 111 | func->old_name || func->new_func || func->old_sympos; \
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| 112 | func++)
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| 113 |
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| 114 | int klp_register_patch(struct klp_patch *);
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| 115 | int klp_unregister_patch(struct klp_patch *);
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| 116 | int klp_enable_patch(struct klp_patch *);
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| 117 | int klp_disable_patch(struct klp_patch *);
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| 118 |
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| 119 |
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| 120 | int klp_module_coming(struct module *mod);
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| 121 | void klp_module_going(struct module *mod);
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| 122 |
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| 123 | #else
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| 124 |
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| 125 | static inline int klp_module_coming(struct module *mod) { return 0; }
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| 126 | static inline void klp_module_going(struct module *mod) { }
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| 127 |
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| 128 | #endif
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| 129 |
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| 130 | #endif
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