cregit-Linux how code gets into the kernel

Release 4.15 kernel/livepatch/core.c

Directory: kernel/livepatch
/*
 * core.c - 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/>.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/kallsyms.h>
#include <linux/livepatch.h>
#include <linux/elf.h>
#include <linux/moduleloader.h>
#include <linux/completion.h>
#include <asm/cacheflush.h>
#include "core.h"
#include "patch.h"
#include "transition.h"

/*
 * klp_mutex is a coarse lock which serializes access to klp data.  All
 * accesses to klp-related variables and structures must have mutex protection,
 * except within the following functions which carefully avoid the need for it:
 *
 * - klp_ftrace_handler()
 * - klp_update_patch_state()
 */

DEFINE_MUTEX(klp_mutex);

static LIST_HEAD(klp_patches);


static struct kobject *klp_root_kobj;




static bool klp_is_module(struct klp_object *obj)
{
	return obj->name;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings16100.00%1100.00%


Total16100.00%1100.00%



/* sets obj->mod if object is not vmlinux and module is found */



static void klp_find_object_module(struct klp_object *obj)
{
	struct module *mod;

	if (!klp_is_module(obj))
		return;

	mutex_lock(&module_mutex);
	/*
         * We do not want to block removal of patched modules and therefore
         * we do not take a reference here. The patches are removed by
         * klp_module_going() instead.
         */
	mod = find_module(obj->name);
	/*
         * Do not mess work of klp_module_coming() and klp_module_going().
         * Note that the patch might still be needed before klp_module_going()
         * is called. Module functions can be called even in the GOING state
         * until mod->exit() finishes. This is especially important for
         * patches that modify semantic of the functions.
         */
	if (mod && mod->klp_alive)
		obj->mod = mod;

	mutex_unlock(&module_mutex);
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings4166.13%133.33%


Petr Mladek1930.65%133.33%


Jessica Yu23.23%133.33%


Total62100.00%3100.00%






static bool klp_is_patch_registered(struct klp_patch *patch)
{
	struct klp_patch *mypatch;

	list_for_each_entry(mypatch, &klp_patches, list)
		if (mypatch == patch)
			return true;

	return false;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings36100.00%1100.00%


Total36100.00%1100.00%






static bool klp_initialized(void)
{
	return !!klp_root_kobj;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings1184.62%150.00%


Nicholas Mc Guire215.38%150.00%


Total13100.00%2100.00%




struct klp_find_arg {
	
const char *objname;
	
const char *name;
	
unsigned long addr;
	
unsigned long count;
	
unsigned long pos;
};




static int klp_find_callback(void *data, const char *name,
			     struct module *mod, unsigned long addr)
{
	struct klp_find_arg *args = data;

	if ((mod && !args->objname) || (!mod && args->objname))
		return 0;

	if (strcmp(args->name, name))
		return 0;

	if (args->objname && strcmp(args->objname, mod->name))
		return 0;

	args->addr = addr;
	args->count++;

	/*
         * Finish the search when the symbol is found for the desired position
         * or the position is not defined for a non-unique symbol.
         */
	if ((args->pos && (args->count == args->pos)) ||
	    (!args->pos && (args->count > 1)))
		return 1;

	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings10273.38%150.00%


Chris J Arges3726.62%150.00%


Total139100.00%2100.00%






static int klp_find_object_symbol(const char *objname, const char *name,
				  unsigned long sympos, unsigned long *addr)
{
	struct klp_find_arg args = {
		.objname = objname,
		.name = name,
		.addr = 0,
		.count = 0,
		.pos = sympos,
        };

	mutex_lock(&module_mutex);
	if (objname)
		module_kallsyms_on_each_symbol(klp_find_callback, &args);
	else
		kallsyms_on_each_symbol(klp_find_callback, &args);
	mutex_unlock(&module_mutex);

	/*
         * Ensure an address was found. If sympos is 0, ensure symbol is unique;
         * otherwise ensure the symbol position count matches sympos.
         */
	if (args.addr == 0)
		pr_err("symbol '%s' not found in symbol table\n", name);
	else if (args.count > 1 && sympos == 0) {
		pr_err("unresolvable ambiguity for symbol '%s' in object '%s'\n",
		       name, objname);
	} else if (sympos != args.count && sympos > 0) {
		pr_err("symbol position %lu for symbol '%s' in object '%s' not found\n",
		       sympos, name, objname ? objname : "vmlinux");
	} else {
		*addr = args.addr;
		return 0;
	}

	*addr = 0;
	return -EINVAL;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings10759.12%120.00%


Chris J Arges4826.52%120.00%


Zhou Chengming137.18%120.00%


Miroslav Benes126.63%120.00%


Petr Mladek10.55%120.00%


Total181100.00%5100.00%






static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod)
{
	int i, cnt, vmlinux, ret;
	char objname[MODULE_NAME_LEN];
	char symname[KSYM_NAME_LEN];
	char *strtab = pmod->core_kallsyms.strtab;
	Elf_Rela *relas;
	Elf_Sym *sym;
	unsigned long sympos, addr;

	/*
         * Since the field widths for objname and symname in the sscanf()
         * call are hard-coded and correspond to MODULE_NAME_LEN and
         * KSYM_NAME_LEN respectively, we must make sure that MODULE_NAME_LEN
         * and KSYM_NAME_LEN have the values we expect them to have.
         *
         * Because the value of MODULE_NAME_LEN can differ among architectures,
         * we use the smallest/strictest upper bound possible (56, based on
         * the current definition of MODULE_NAME_LEN) to prevent overflows.
         */
	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);

	relas = (Elf_Rela *) relasec->sh_addr;
	/* For each rela in this klp relocation section */
	for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) {
		sym = pmod->core_kallsyms.symtab + ELF_R_SYM(relas[i].r_info);
		if (sym->st_shndx != SHN_LIVEPATCH) {
			pr_err("symbol %s is not marked as a livepatch symbol\n",
			       strtab + sym->st_name);
			return -EINVAL;
		}

		/* Format: .klp.sym.objname.symname,sympos */
		cnt = sscanf(strtab + sym->st_name,
			     ".klp.sym.%55[^.].%127[^,],%lu",
			     objname, symname, &sympos);
		if (cnt != 3) {
			pr_err("symbol %s has an incorrectly formatted name\n",
			       strtab + sym->st_name);
			return -EINVAL;
		}

		/* klp_find_object_symbol() treats a NULL objname as vmlinux */
		vmlinux = !strcmp(objname, "vmlinux");
		ret = klp_find_object_symbol(vmlinux ? NULL : objname,
					     symname, sympos, &addr);
		if (ret)
			return ret;

		sym->st_value = addr;
	}

	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Jessica Yu19080.17%120.00%


Seth Jennings4217.72%120.00%


Peter Zijlstra20.84%120.00%


Josh Poimboeuf20.84%120.00%


Chris J Arges10.42%120.00%


Total237100.00%5100.00%






static int klp_write_object_relocations(struct module *pmod,
					struct klp_object *obj)
{
	int i, cnt, ret = 0;
	const char *objname, *secname;
	char sec_objname[MODULE_NAME_LEN];
	Elf_Shdr *sec;

	if (WARN_ON(!klp_is_object_loaded(obj)))
		return -EINVAL;

	objname = klp_is_module(obj) ? obj->name : "vmlinux";

	/* For each klp relocation section */
	for (i = 1; i < pmod->klp_info->hdr.e_shnum; i++) {
		sec = pmod->klp_info->sechdrs + i;
		secname = pmod->klp_info->secstrings + sec->sh_name;
		if (!(sec->sh_flags & SHF_RELA_LIVEPATCH))
			continue;

		/*
                 * Format: .klp.rela.sec_objname.section_name
                 * See comment in klp_resolve_symbols() for an explanation
                 * of the selected field width value.
                 */
		cnt = sscanf(secname, ".klp.rela.%55[^.]", sec_objname);
		if (cnt != 1) {
			pr_err("section %s has an incorrectly formatted name\n",
			       secname);
			ret = -EINVAL;
			break;
		}

		if (strcmp(objname, sec_objname))
			continue;

		ret = klp_resolve_symbols(sec, pmod);
		if (ret)
			break;

		ret = apply_relocate_add(pmod->klp_info->sechdrs,
					 pmod->core_kallsyms.strtab,
					 pmod->klp_info->symndx, i, pmod);
		if (ret)
			break;
	}

	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Jessica Yu11652.97%116.67%


Seth Jennings8739.73%116.67%


Chris J Arges73.20%116.67%


Josh Poimboeuf73.20%233.33%


Zhou Chengming20.91%116.67%


Total219100.00%6100.00%






static int __klp_disable_patch(struct klp_patch *patch)
{
	struct klp_object *obj;

	if (WARN_ON(!patch->enabled))
		return -EINVAL;

	if (klp_transition_patch)
		return -EBUSY;

	/* enforce stacking: only the last enabled patch can be disabled */
	if (!list_is_last(&patch->list, &klp_patches) &&
	    list_next_entry(patch, list)->enabled)
		return -EBUSY;

	klp_init_transition(patch, KLP_UNPATCHED);

	klp_for_each_object(patch, obj)
		if (obj->patched)
			klp_pre_unpatch_callback(obj);

	/*
         * Enforce the order of the func->transition writes in
         * klp_init_transition() and the TIF_PATCH_PENDING writes in
         * klp_start_transition().  In the rare case where klp_ftrace_handler()
         * is called shortly after klp_update_patch_state() switches the task,
         * this ensures the handler sees that func->transition is set.
         */
	smp_wmb();

	klp_start_transition();
	klp_try_complete_transition();
	patch->enabled = false;

	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Josh Poimboeuf4944.95%440.00%


Joe Lawrence2220.18%110.00%


Seth Jennings1816.51%110.00%


Petr Mladek1412.84%220.00%


Michael Ellerman32.75%110.00%


Li Bin32.75%110.00%


Total109100.00%10100.00%



/**
 * klp_disable_patch() - disables a registered patch
 * @patch:      The registered, enabled patch to be disabled
 *
 * Unregisters the patched functions from ftrace.
 *
 * Return: 0 on success, otherwise error
 */



int klp_disable_patch(struct klp_patch *patch)
{
	int ret;

	mutex_lock(&klp_mutex);

	if (!klp_is_patch_registered(patch)) {
		ret = -EINVAL;
		goto err;
	}

	if (!patch->enabled) {
		ret = -EINVAL;
		goto err;
	}

	ret = __klp_disable_patch(patch);

err:
	mutex_unlock(&klp_mutex);
	return ret;
}

Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings6590.28%125.00%


Minfei Huang56.94%125.00%


Josh Poimboeuf22.78%250.00%


Total72100.00%4100.00%




EXPORT_SYMBOL_GPL(klp_disable_patch);




static int __klp_enable_patch(struct klp_patch *patch)
{
	struct klp_object *obj;
	int ret;

	if (klp_transition_patch)
		return -EBUSY;

	if (WARN_ON(patch->enabled))
		return -EINVAL;

	/* enforce stacking: only the first disabled patch can be enabled */
	if (patch->list.prev != &klp_patches &&
	    !list_prev_entry(patch, list)->enabled)
		return -EBUSY;

	/*
         * A reference is taken on the patch module to prevent it from being
         * unloaded.
         *
         * Note: For immediate (no consistency model) patches we don't allow
         * patch modules to unload since there is no safe/sane method to
         * determine if a thread is still running in the patched code contained
         * in the patch module once the ftrace registration is successful.
         */
	if (!try_module_get(patch->mod))
		return -ENODEV;

	pr_notice("enabling patch '%s'\n", patch->mod->name);

	klp_init_transition(patch, KLP_PATCHED);

	/*
         * Enforce the order of the func->transition writes in
         * klp_init_transition() and the ops->func_stack writes in
         * klp_patch_object(), so that klp_ftrace_handler() will see the
         * func->transition updates before the handler is registered and the
         * new funcs become visible to the handler.
         */
	smp_wmb();

	klp_for_each_object(patch, obj) {
		if (!klp_is_object_loaded(obj))
			continue;

		ret = klp_pre_patch_callback(obj);
		if (ret) {
			pr_warn("pre-patch callback failed for object '%s'\n",
				klp_is_module(obj) ? obj->name : "vmlinux");
			goto err;
		}

		ret = klp_patch_object(obj);
		if (ret) {
			pr_warn("failed to patch object '%s'\n",
				klp_is_module(obj) ? obj->name : "vmlinux");
			goto err;
		}
	}

	klp_start_transition();
	klp_try_complete_transition();
	patch->enabled = true;

	return 0;
err:
	pr_warn("failed to enable patch '%s'\n", patch->mod->name);

	klp_cancel_transition();
	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Josh Poimboeuf7936.24%457.14%


Seth Jennings7132.57%114.29%


Joe Lawrence6228.44%114.29%


Jiri Slaby62.75%114.29%


Total218100.00%7100.00%



/**
 * klp_enable_patch() - enables a registered patch
 * @patch:      The registered, disabled patch to be enabled
 *
 * Performs the needed symbol lookups and code relocations,
 * then registers the patched functions with ftrace.
 *
 * Return: 0 on success, otherwise error
 */



int klp_enable_patch(struct klp_patch *patch)
{
	int ret;

	mutex_lock(&klp_mutex);

	if (!klp_is_patch_registered(patch)) {
		ret = -EINVAL;
		goto err;
	}

	ret = __klp_enable_patch(patch);

err:
	mutex_unlock(&klp_mutex);
	return ret;
}

Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings55100.00%1100.00%


Total55100.00%1100.00%




EXPORT_SYMBOL_GPL(klp_enable_patch);

/*
 * Sysfs Interface
 *
 * /sys/kernel/livepatch
 * /sys/kernel/livepatch/<patch>
 * /sys/kernel/livepatch/<patch>/enabled
 * /sys/kernel/livepatch/<patch>/transition
 * /sys/kernel/livepatch/<patch>/<object>
 * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
 */




static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr,
			     const char *buf, size_t count)
{
	struct klp_patch *patch;
	int ret;
	bool enabled;

	ret = kstrtobool(buf, &enabled);
	if (ret)
		return ret;

	patch = container_of(kobj, struct klp_patch, kobj);

	mutex_lock(&klp_mutex);

	if (!klp_is_patch_registered(patch)) {
		/*
                 * Module with the patch could either disappear meanwhile or is
                 * not properly initialized yet.
                 */
		ret = -EINVAL;
		goto err;
	}

	if (patch->enabled == enabled) {
		/* already in requested state */
		ret = -EINVAL;
		goto err;
	}

	if (patch == klp_transition_patch) {
		klp_reverse_transition();
	} else if (enabled) {
		ret = __klp_enable_patch(patch);
		if (ret)
			goto err;
	} else {
		ret = __klp_disable_patch(patch);
		if (ret)
			goto err;
	}

	mutex_unlock(&klp_mutex);

	return count;

err:
	mutex_unlock(&klp_mutex);
	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings13877.97%120.00%


Josh Poimboeuf3922.03%480.00%


Total177100.00%5100.00%






static ssize_t enabled_show(struct kobject *kobj,
			    struct kobj_attribute *attr, char *buf)
{
	struct klp_patch *patch;

	patch = container_of(kobj, struct klp_patch, kobj);
	return snprintf(buf, PAGE_SIZE-1, "%d\n", patch->enabled);
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings5298.11%150.00%


Josh Poimboeuf11.89%150.00%


Total53100.00%2100.00%






static ssize_t transition_show(struct kobject *kobj,
			       struct kobj_attribute *attr, char *buf)
{
	struct klp_patch *patch;

	patch = container_of(kobj, struct klp_patch, kobj);
	return snprintf(buf, PAGE_SIZE-1, "%d\n",
			patch == klp_transition_patch);
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings5094.34%150.00%


Josh Poimboeuf35.66%150.00%


Total53100.00%2100.00%




static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled);

static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition);

static struct attribute *klp_patch_attrs[] = {
	&enabled_kobj_attr.attr,
	&transition_kobj_attr.attr,
	NULL
};




static void klp_kobj_release_patch(struct kobject *kobj)
{
	struct klp_patch *patch;

	patch = container_of(kobj, struct klp_patch, kobj);
	complete(&patch->finish);
}


Contributors
PersonTokensPropCommitsCommitProp
Josh Poimboeuf2569.44%150.00%


Seth Jennings1130.56%150.00%


Total36100.00%2100.00%




static struct kobj_type klp_ktype_patch = {
	.release = klp_kobj_release_patch,
	.sysfs_ops = &kobj_sysfs_ops,
	.default_attrs = klp_patch_attrs,
};




static void klp_kobj_release_object(struct kobject *kobj)
{
}


Contributors
PersonTokensPropCommitsCommitProp
Miroslav Benes10100.00%1100.00%


Total10100.00%1100.00%




static struct kobj_type klp_ktype_object = {
	.release = klp_kobj_release_object,
	.sysfs_ops = &kobj_sysfs_ops,
};




static void klp_kobj_release_func(struct kobject *kobj)
{
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings990.00%150.00%


Josh Poimboeuf110.00%150.00%


Total10100.00%2100.00%




static struct kobj_type klp_ktype_func = {
	.release = klp_kobj_release_func,
	.sysfs_ops = &kobj_sysfs_ops,
};

/*
 * Free all functions' kobjects in the array up to some limit. When limit is
 * NULL, all kobjects are freed.
 */



static void klp_free_funcs_limited(struct klp_object *obj,
				   struct klp_func *limit)
{
	struct klp_func *func;

	for (func = obj->funcs; func->old_name && func != limit; func++)
		kobject_put(&func->kobj);
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings48100.00%1100.00%


Total48100.00%1100.00%



/* Clean up when a patched object is unloaded */



static void klp_free_object_loaded(struct klp_object *obj)
{
	struct klp_func *func;

	obj->mod = NULL;

	klp_for_each_func(obj, func)
		func->old_addr = 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings2882.35%150.00%


Jiri Slaby617.65%150.00%


Total34100.00%2100.00%



/*
 * Free all objects' kobjects in the array up to some limit. When limit is
 * NULL, all kobjects are freed.
 */



static void klp_free_objects_limited(struct klp_patch *patch,
				     struct klp_object *limit)
{
	struct klp_object *obj;

	for (obj = patch->objs; obj->funcs && obj != limit; obj++) {
		klp_free_funcs_limited(obj, NULL);
		kobject_put(&obj->kobj);
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings5698.25%150.00%


Miroslav Benes11.75%150.00%


Total57100.00%2100.00%






static void klp_free_patch(struct klp_patch *patch)
{
	klp_free_objects_limited(patch, NULL);
	if (!list_empty(&patch->list))
		list_del(&patch->list);
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings37100.00%1100.00%


Total37100.00%1100.00%






static int klp_init_func(struct klp_object *obj, struct klp_func *func)
{
	if (!func->old_name || !func->new_func)
		return -EINVAL;

	INIT_LIST_HEAD(&func->stack_node);
	func->patched = false;
	func->transition = false;

	/* The format for the sysfs directory is <function,sympos> where sympos
         * is the nth occurrence of this symbol in kallsyms for the patched
         * object. If the user selects 0 for old_sympos, then 1 will be used
         * since a unique symbol will be the first occurrence.
         */
	return kobject_init_and_add(&func->kobj, &klp_ktype_func,
				    &obj->kobj, "%s,%lu", func->old_name,
				    func->old_sympos ? func->old_sympos : 1);
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings4552.33%112.50%


Miroslav Benes1719.77%225.00%


Chris J Arges1213.95%112.50%


Josh Poimboeuf1112.79%337.50%


Jiri Kosina11.16%112.50%


Total86100.00%8100.00%



/* Arches may override this to finish any remaining arch-specific tasks */



void __weak arch_klp_init_object_loaded(struct klp_patch *patch,
					struct klp_object *obj)
{
}


Contributors
PersonTokensPropCommitsCommitProp
Jessica Yu15100.00%1100.00%


Total15100.00%1100.00%



/* parts of the initialization that is done only when the object is loaded */



static int klp_init_object_loaded(struct klp_patch *patch,
				  struct klp_object *obj)
{
	struct klp_func *func;
	int ret;

	module_disable_ro(patch->mod);
	ret = klp_write_object_relocations(patch->mod, obj);
	if (ret) {
		module_enable_ro(patch->mod, true);
		return ret;
	}

	arch_klp_init_object_loaded(patch, obj);
	module_enable_ro(patch->mod, true);

	klp_for_each_func(obj, func) {
		ret = klp_find_object_symbol(obj->name, func->old_name,
					     func->old_sympos,
					     &func->old_addr);
		if (ret)
			return ret;

		ret = kallsyms_lookup_size_offset(func->old_addr,
						  &func->old_size, NULL);
		if (!ret) {
			pr_err("kallsyms size lookup failed for '%s'\n",
			       func->old_name);
			return -ENOENT;
		}

		ret = kallsyms_lookup_size_offset((unsigned long)func->new_func,
						  &func->new_size, NULL);
		if (!ret) {
			pr_err("kallsyms size lookup failed for '%s' replacement\n",
			       func->old_name);
			return -ENOENT;
		}
	}

	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Josh Poimboeuf7639.58%120.00%


Seth Jennings6232.29%120.00%


Jessica Yu3417.71%120.00%


Chris J Arges147.29%120.00%


Jiri Slaby63.12%120.00%


Total192100.00%5100.00%






static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)
{
	struct klp_func *func;
	int ret;
	const char *name;

	if (!obj->funcs)
		return -EINVAL;

	obj->patched = false;
	obj->mod = NULL;

	klp_find_object_module(obj);

	name = klp_is_module(obj) ? obj->name : "vmlinux";
	ret = kobject_init_and_add(&obj->kobj, &klp_ktype_object,
				   &patch->kobj, "%s", name);
	if (ret)
		return ret;

	klp_for_each_func(obj, func) {
		ret = klp_init_func(obj, func);
		if (ret)
			goto free;
	}

	if (klp_is_object_loaded(obj)) {
		ret = klp_init_object_loaded(patch, obj);
		if (ret)
			goto free;
	}

	return 0;

free:
	klp_free_funcs_limited(obj, func);
	kobject_put(&obj->kobj);
	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings14283.04%120.00%


Miroslav Benes158.77%120.00%


Petr Mladek63.51%120.00%


Jiri Slaby63.51%120.00%


Josh Poimboeuf21.17%120.00%


Total171100.00%5100.00%






static int klp_init_patch(struct klp_patch *patch)
{
	struct klp_object *obj;
	int ret;

	if (!patch->objs)
		return -EINVAL;

	mutex_lock(&klp_mutex);

	patch->enabled = false;
	init_completion(&patch->finish);

	ret = kobject_init_and_add(&patch->kobj, &klp_ktype_patch,
				   klp_root_kobj, "%s", patch->mod->name);
	if (ret) {
		mutex_unlock(&klp_mutex);
		return ret;
	}

	klp_for_each_object(patch, obj) {
		ret = klp_init_object(patch, obj);
		if (ret)
			goto free;
	}

	list_add_tail(&patch->list, &klp_patches);

	mutex_unlock(&klp_mutex);

	return 0;

free:
	klp_free_objects_limited(patch, obj);

	mutex_unlock(&klp_mutex);

	kobject_put(&patch->kobj);
	wait_for_completion(&patch->finish);

	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings12776.51%116.67%


Josh Poimboeuf3118.67%350.00%


Jiri Slaby63.61%116.67%


Jiri Kosina21.20%116.67%


Total166100.00%6100.00%



/**
 * klp_unregister_patch() - unregisters a patch
 * @patch:      Disabled patch to be unregistered
 *
 * Frees the data structures and removes the sysfs interface.
 *
 * Return: 0 on success, otherwise error
 */



int klp_unregister_patch(struct klp_patch *patch)
{
	int ret;

	mutex_lock(&klp_mutex);

	if (!klp_is_patch_registered(patch)) {
		ret = -EINVAL;
		goto err;
	}

	if (patch->enabled) {
		ret = -EBUSY;
		goto err;
	}

	klp_free_patch(patch);

	mutex_unlock(&klp_mutex);

	kobject_put(&patch->kobj);
	wait_for_completion(&patch->finish);

	return 0;
err:
	mutex_unlock(&klp_mutex);
	return ret;
}

Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings6569.15%133.33%


Josh Poimboeuf2930.85%266.67%


Total94100.00%3100.00%




EXPORT_SYMBOL_GPL(klp_unregister_patch);

/**
 * klp_register_patch() - registers a patch
 * @patch:      Patch to be registered
 *
 * Initializes the data structure associated with the patch and
 * creates the sysfs interface.
 *
 * There is no need to take the reference on the patch module here. It is done
 * later when the patch is enabled.
 *
 * Return: 0 on success, otherwise error
 */



int klp_register_patch(struct klp_patch *patch)
{
	if (!patch || !patch->mod)
		return -EINVAL;

	if (!is_livepatch_module(patch->mod)) {
		pr_err("module %s is not marked as a livepatch module\n",
		       patch->mod->name);
		return -EINVAL;
	}

	if (!klp_initialized())
		return -ENODEV;

	/*
         * Architectures without reliable stack traces have to set
         * patch->immediate because there's currently no way to patch kthreads
         * with the consistency model.
         */
	if (!klp_have_reliable_stack() && !patch->immediate) {
		pr_err("This architecture doesn't have support for the livepatch consistency model.\n");
		return -ENOSYS;
	}

	return klp_init_patch(patch);
}

Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings5055.56%120.00%


Jessica Yu1820.00%120.00%


Josh Poimboeuf1516.67%240.00%


Jiri Kosina77.78%120.00%


Total90100.00%5100.00%




EXPORT_SYMBOL_GPL(klp_register_patch);

/*
 * Remove parts of patches that touch a given kernel module. The list of
 * patches processed might be limited. When limit is NULL, all patches
 * will be handled.
 */



static void klp_cleanup_module_patches_limited(struct module *mod,
					       struct klp_patch *limit)
{
	struct klp_patch *patch;
	struct klp_object *obj;

	list_for_each_entry(patch, &klp_patches, list) {
		if (patch == limit)
			break;

		klp_for_each_object(patch, obj) {
			if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
				continue;

			/*
                         * Only unpatch the module if the patch is enabled or
                         * is in transition.
                         */
			if (patch->enabled || patch == klp_transition_patch) {

				if (patch != klp_transition_patch)
					klp_pre_unpatch_callback(obj);

				pr_notice("reverting patch '%s' on unloading module '%s'\n",
					  patch->mod->name, obj->mod->name);
				klp_unpatch_object(obj);

				klp_post_unpatch_callback(obj);
			}

			klp_free_object_loaded(obj);
			break;
		}
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Joe Lawrence11287.50%150.00%


Jiri Kosina1612.50%150.00%


Total128100.00%2100.00%






int klp_module_coming(struct module *mod)
{
	int ret;
	struct klp_patch *patch;
	struct klp_object *obj;

	if (WARN_ON(mod->state != MODULE_STATE_COMING))
		return -EINVAL;

	mutex_lock(&klp_mutex);
	/*
         * Each module has to know that klp_module_coming()
         * has been called. We never know what module will
         * get patched by a new patch.
         */
	mod->klp_alive = true;

	list_for_each_entry(patch, &klp_patches, list) {
		klp_for_each_object(patch, obj) {
			if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
				continue;

			obj->mod = mod;

			ret = klp_init_object_loaded(patch, obj);
			if (ret) {
				pr_warn("failed to initialize patch '%s' for module '%s' (%d)\n",
					patch->mod->name, obj->mod->name, ret);
				goto err;
			}

			/*
                         * Only patch the module if the patch is enabled or is
                         * in transition.
                         */
			if (!patch->enabled && patch != klp_transition_patch)
				break;

			pr_notice("applying patch '%s' to loading module '%s'\n",
				  patch->mod->name, obj->mod->name);

			ret = klp_pre_patch_callback(obj);
			if (ret) {
				pr_warn("pre-patch callback failed for object '%s'\n",
					obj->name);
				goto err;
			}

			ret = klp_patch_object(obj);
			if (ret) {
				pr_warn("failed to apply patch '%s' to module '%s' (%d)\n",
					patch->mod->name, obj->mod->name, ret);

				klp_post_unpatch_callback(obj);
				goto err;
			}

			if (patch != klp_transition_patch)
				klp_post_patch_callback(obj);

			break;
		}
	}

	mutex_unlock(&klp_mutex);

	return 0;

err:
	/*
         * If a patch is unsuccessfully applied, return
         * error to the module loader.
         */
	pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n",
		patch->mod->name, obj->mod->name, obj->mod->name);
	mod->klp_alive = false;
	klp_cleanup_module_patches_limited(mod, patch);
	mutex_unlock(&klp_mutex);

	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Jessica Yu13445.27%114.29%


Seth Jennings9030.41%114.29%


Joe Lawrence4515.20%228.57%


Minfei Huang196.42%114.29%


Josh Poimboeuf82.70%228.57%


Total296100.00%7100.00%






void klp_module_going(struct module *mod)
{
	if (WARN_ON(mod->state != MODULE_STATE_GOING &&
		    mod->state != MODULE_STATE_COMING))
		return;

	mutex_lock(&klp_mutex);
	/*
         * Each module has to know that klp_module_going()
         * has been called. We never know what module will
         * get patched by a new patch.
         */
	mod->klp_alive = false;

	klp_cleanup_module_patches_limited(mod, NULL);

	mutex_unlock(&klp_mutex);
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings2953.70%125.00%


Jessica Yu1731.48%125.00%


Petr Mladek611.11%125.00%


Joe Lawrence23.70%125.00%


Total54100.00%4100.00%






static int __init klp_init(void)
{
	int ret;

	ret = klp_check_compiler_support();
	if (ret) {
		pr_info("Your compiler is too old; turning off.\n");
		return -EINVAL;
	}

	klp_root_kobj = kobject_create_and_add("livepatch", kernel_kobj);
	if (!klp_root_kobj)
		return -ENOMEM;

	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings3260.38%125.00%


Jiri Kosina1833.96%125.00%


Jessica Yu23.77%125.00%


Minfei Huang11.89%125.00%


Total53100.00%4100.00%




module_init(klp_init);

Overall Contributors
PersonTokensPropCommitsCommitProp
Seth Jennings189154.83%12.38%


Jessica Yu53515.51%37.14%


Josh Poimboeuf41011.89%1126.19%


Joe Lawrence2447.07%24.76%


Chris J Arges1233.57%37.14%


Miroslav Benes732.12%37.14%


Jiri Kosina471.36%511.90%


Petr Mladek461.33%49.52%


Jiri Slaby300.87%12.38%


Minfei Huang250.72%37.14%


Zhou Chengming150.43%24.76%


Michael Ellerman30.09%12.38%


Li Bin30.09%12.38%


Peter Zijlstra20.06%12.38%


Nicholas Mc Guire20.06%12.38%


Total3449100.00%42100.00%


Directory: kernel/livepatch



Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.