Commit 1f8a38ca authored by Zheng Yejian's avatar Zheng Yejian Committed by Zheng Zengkai
Browse files

livepatch: Fix patching functions which have static_call 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60L10


CVE: NA

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

It was reported that if 'static_call' is used in a old function, then
the livepatch module created by kpatch for that old function cannot be
inserted normally.

Root cause is that relocation of static_call symbols in livepatch module
has not been done while initing:
  load_module
    prepare_coming_module
      blocking_notifier_call_chain_robust
        notifier_call_chain_robust
          static_call_module_notify
            <-- 1. static_call symbols init here, but relocation is done
                   at below MARK "2."
    do_init_module
      do_one_initcall
        klp_register_patch
          klp_init_patch
            klp_init_object
              klp_init_object_loaded    <--  2. relocate .klp.xxx here

To solve it, we move the static_call initialization after relocation.

Signed-off-by: default avatarZheng Yejian <zhengyejian1@huawei.com>
Reviewed-by: default avatarKuohai Xu <xukuohai@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 494188df

kernel/livepatch/core.c

+19 −0
Original line number Diff line number Diff line
@@ -1192,6 +1192,12 @@ static void klp_init_patch_early(struct klp_patch *patch) 
	}

}



#if defined(CONFIG_HAVE_STATIC_CALL_INLINE)

extern int klp_static_call_register(struct module *mod);

#else

static inline int klp_static_call_register(struct module *mod) { return 0; }

#endif



static int klp_init_patch(struct klp_patch *patch)

{

	struct klp_object *obj;
@@ -1223,6 +1229,19 @@ static int klp_init_patch(struct klp_patch *patch) 
		pr_err("register jump label failed, ret=%d\n", ret);

		return ret;

	}

	ret = klp_static_call_register(patch->mod);

	if (ret) {

		/*

		 * We no need to distinctly clean pre-registered jump_label

		 * here because it will be clean at path:

		 *   load_module

		 *     do_init_module

		 *       fail_free_freeinit:  <-- notify GOING here

		 */

		module_enable_ro(patch->mod, true);

		pr_err("register static call failed, ret=%d\n", ret);

		return ret;

	}

	module_enable_ro(patch->mod, true);



#ifdef CONFIG_LIVEPATCH_STOP_MACHINE_CONSISTENCY

kernel/static_call.c

+19 −0
Original line number Diff line number Diff line
@@ -356,6 +356,9 @@ static int static_call_add_module(struct module *mod) 
	struct static_call_site *stop = start + mod->num_static_call_sites;

	struct static_call_site *site;



	if (unlikely(!mod_klp_rel_completed(mod)))

		return 0;



	for (site = start; site != stop; site++) {

		unsigned long s_key = __static_call_key(site);

		unsigned long addr = s_key & ~STATIC_CALL_SITE_FLAGS;
@@ -398,6 +401,9 @@ static void static_call_del_module(struct module *mod) 
	struct static_call_mod *site_mod, **prev;

	struct static_call_site *site;



	if (unlikely(!mod_klp_rel_completed(mod)))

		return;



	for (site = start; site < stop; site++) {

		key = static_call_key(site);

		if (key == prev_key)
@@ -450,8 +456,21 @@ static struct notifier_block static_call_module_nb = { 
	.notifier_call = static_call_module_notify,

};



int klp_static_call_register(struct module *mod)

{

	int ret;



	ret = static_call_module_notify(&static_call_module_nb, MODULE_STATE_COMING, mod);

	return notifier_to_errno(ret);

}



#else



int klp_static_call_register(struct module *mod)

{

	return 0;

}



static inline int __static_call_mod_text_reserved(void *start, void *end)

{

	return 0;