Commit 315bed18 authored by Zheng Yejian's avatar Zheng Yejian
Browse files

livepatch/core: Support jump_label 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8MGE6


CVE: NA

--------------------------------

The kpatch-build processes the __jump_table special section,
and only the jump_lable used by the changed functions will be
included in __jump_table section, and the livepatch should
process the tracepoint again after the dynamic relocation.

NOTE: adding new tracepoints definition is not supported.

Signed-off-by: default avatarCheng Jian <cj.chengjian@huawei.com>
Signed-off-by: default avatarWang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: default avatarDong Kai <dongkai11@huawei.com>
Signed-off-by: default avatarYe Weihua <yeweihua4@huawei.com>
Signed-off-by: default avatarZheng Yejian <zhengyejian1@huawei.com>
parent c001741b

include/linux/jump_label.h

+10 −0
Original line number Diff line number Diff line
@@ -235,6 +235,9 @@ extern void static_key_disable(struct static_key *key); 
extern void static_key_enable_cpuslocked(struct static_key *key);

extern void static_key_disable_cpuslocked(struct static_key *key);

extern enum jump_label_type jump_label_init_type(struct jump_entry *entry);

#ifdef CONFIG_LIVEPATCH_WO_FTRACE

extern int jump_label_register(struct module *mod);

#endif



/*

 * We should be using ATOMIC_INIT() for initializing .enabled, but
@@ -314,6 +317,13 @@ static inline int jump_label_text_reserved(void *start, void *end) 
static inline void jump_label_lock(void) {}

static inline void jump_label_unlock(void) {}



#ifdef CONFIG_LIVEPATCH_WO_FTRACE

static inline int jump_label_register(struct module *mod)

{

	return 0;

}

#endif



static inline void static_key_enable(struct static_key *key)

{

	STATIC_KEY_CHECK_USE(key);

include/linux/module.h

+33 −0
Original line number Diff line number Diff line
@@ -383,6 +383,12 @@ struct mod_kallsyms { 
};



#ifdef CONFIG_LIVEPATCH

enum MODULE_KLP_REL_STATE {

	MODULE_KLP_REL_NONE = 0,

	MODULE_KLP_REL_UNDO,

	MODULE_KLP_REL_DONE,

};



/**

 * struct klp_modinfo - ELF information preserved from the livepatch module

 *
@@ -551,6 +557,19 @@ struct module { 


	/* ELF information */

	struct klp_modinfo *klp_info;

	/*

	 * livepatch should relocate the key of jump_label by

	 * using klp_apply_section_relocs. So it's necessary to

	 * do jump_label_apply_nops() and jump_label_add_module()

	 * later after livepatch relocation finised.

	 *

	 * for normal module :

	 *	always MODULE_KLP_REL_DONE.

	 * for livepatch module :

	 *	init as MODULE_KLP_REL_UNDO,

	 *	set to MODULE_KLP_REL_DONE when relocate completed.

	 */

	enum MODULE_KLP_REL_STATE klp_rel_state; /* Only used in the solution without ftrace */

#endif



#ifdef CONFIG_PRINTK_INDEX
@@ -750,6 +769,20 @@ static inline bool is_livepatch_module(struct module *mod) 
#endif

}



#ifdef CONFIG_LIVEPATCH_WO_FTRACE

static inline void set_mod_klp_rel_state(struct module *mod,

			enum MODULE_KLP_REL_STATE state)

{

	mod->klp_rel_state = state;

}



static inline bool mod_klp_rel_completed(struct module *mod)

{

	return mod->klp_rel_state == MODULE_KLP_REL_NONE ||

		mod->klp_rel_state == MODULE_KLP_REL_DONE;

}

#endif /* CONFIG_LIVEPATCH_WO_FTRACE */



void set_module_sig_enforced(void);



#else /* !CONFIG_MODULES... */

kernel/jump_label.c

+22 −0
Original line number Diff line number Diff line
@@ -628,6 +628,11 @@ static int jump_label_add_module(struct module *mod) 
	struct static_key *key = NULL;

	struct static_key_mod *jlm, *jlm2;



#ifdef CONFIG_LIVEPATCH_WO_FTRACE

	if (unlikely(!mod_klp_rel_completed(mod)))

		return 0;

#endif



	/* if the module doesn't have jump label entries, just return */

	if (iter_start == iter_stop)

		return 0;
@@ -690,6 +695,11 @@ static void jump_label_del_module(struct module *mod) 
	struct static_key *key = NULL;

	struct static_key_mod *jlm, **prev;



#ifdef CONFIG_LIVEPATCH_WO_FTRACE

	if (unlikely(!mod_klp_rel_completed(mod)))

		return;

#endif



	for (iter = iter_start; iter < iter_stop; iter++) {

		if (jump_entry_key(iter) == key)

			continue;
@@ -766,6 +776,18 @@ static struct notifier_block jump_label_module_nb = { 
	.priority = 1, /* higher than tracepoints */

};



#ifdef CONFIG_LIVEPATCH_WO_FTRACE

int jump_label_register(struct module *mod)

{

	int ret;



	ret = jump_label_module_notify(&jump_label_module_nb,

			MODULE_STATE_COMING, mod);



	return notifier_to_errno(ret);

}

#endif /* CONFIG_LIVEPATCH_WO_FTRACE */



static __init int jump_label_init_module(void)

{

	return register_module_notifier(&jump_label_module_nb);

kernel/livepatch/core.c

+6 −0
Original line number Diff line number Diff line
@@ -1060,6 +1060,12 @@ static int klp_init_patch(struct klp_patch *patch) 
	}



#ifdef CONFIG_LIVEPATCH_WO_FTRACE

	set_mod_klp_rel_state(patch->mod, MODULE_KLP_REL_DONE);

	ret = jump_label_register(patch->mod);

	if (ret) {

		pr_err("register jump label failed, ret=%d\n", ret);

		return ret;

	}

	klp_for_each_object(patch, obj)

		klp_load_hook(obj);

#endif

kernel/module/main.c

+8 −0
Original line number Diff line number Diff line
@@ -1918,9 +1918,17 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l 


static int check_modinfo_livepatch(struct module *mod, struct load_info *info)

{

#ifdef CONFIG_LIVEPATCH_WO_FTRACE

	if (!get_modinfo(info, "livepatch")) {

		set_mod_klp_rel_state(mod, MODULE_KLP_REL_NONE);

		return 0;

	}

	set_mod_klp_rel_state(mod, MODULE_KLP_REL_UNDO);

#else /* !CONFIG_LIVEPATCH_WO_FTRACE */

	if (!get_modinfo(info, "livepatch"))

		/* Nothing more to do */

		return 0;

#endif /* CONFIG_LIVEPATCH_WO_FTRACE */



	if (set_livepatch_module(mod))

		return 0;