| /* 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> |
| |
| #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 |
| * @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_ */ |