Commit 1be9473e authored by Aaron Tomlin's avatar Aaron Tomlin Committed by Luis Chamberlain
Browse files

module: Move livepatch support to a separate file 



No functional change.

This patch migrates livepatch support (i.e. used during module
add/or load and remove/or deletion) from core module code into
kernel/module/livepatch.c. At the moment it contains code to
persist Elf information about a given livepatch module, only.
The new file was added to MAINTAINERS.

Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Tested-by: default avatarPetr Mladek <pmladek@suse.com>
Signed-off-by: default avatarAaron Tomlin <atomlin@redhat.com>
Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
parent 5aff4dfd

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -11360,6 +11360,7 @@ F: arch/s390/include/asm/livepatch.h 
F:	arch/x86/include/asm/livepatch.h

F:	include/linux/livepatch.h

F:	kernel/livepatch/

F:	kernel/module/livepatch.c

F:	lib/livepatch/

F:	samples/livepatch/

F:	tools/testing/selftests/livepatch/

include/linux/module.h

+3 −6
Original line number Diff line number Diff line
@@ -663,17 +663,14 @@ static inline bool module_requested_async_probing(struct module *module) 
	return module && module->async_probe_requested;

}



#ifdef CONFIG_LIVEPATCH

static inline bool is_livepatch_module(struct module *mod)

{

#ifdef CONFIG_LIVEPATCH

	return mod->klp;

}

#else /* !CONFIG_LIVEPATCH */

static inline bool is_livepatch_module(struct module *mod)

{

#else

	return false;

#endif

}

#endif /* CONFIG_LIVEPATCH */



bool is_module_sig_enforced(void);

void set_module_sig_enforced(void);

kernel/module/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -10,3 +10,4 @@ KCOV_INSTRUMENT_module.o := n 
obj-y += main.o

obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o

obj-$(CONFIG_MODULE_SIG) += signing.o

obj-$(CONFIG_LIVEPATCH) += livepatch.o

kernel/module/internal.h

+22 −0
Original line number Diff line number Diff line
@@ -57,6 +57,28 @@ struct load_info { 


int mod_verify_sig(const void *mod, struct load_info *info);



#ifdef CONFIG_LIVEPATCH

int copy_module_elf(struct module *mod, struct load_info *info);

void free_module_elf(struct module *mod);

#else /* !CONFIG_LIVEPATCH */

static inline int copy_module_elf(struct module *mod, struct load_info *info)

{

	return 0;

}



static inline void free_module_elf(struct module *mod) { }

#endif /* CONFIG_LIVEPATCH */



static inline bool set_livepatch_module(struct module *mod)

{

#ifdef CONFIG_LIVEPATCH

	mod->klp = true;

	return true;

#else

	return false;

#endif

}



#ifdef CONFIG_MODULE_DECOMPRESS

int module_decompress(struct load_info *info, const void *buf, size_t size);

void module_decompress_cleanup(struct load_info *info);

kernel/module/livepatch.c

0 → 100644
+74 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * Module livepatch support

 *

 * Copyright (C) 2016 Jessica Yu <jeyu@redhat.com>

 */



#include <linux/module.h>

#include <linux/string.h>

#include <linux/slab.h>

#include "internal.h"



/*

 * Persist Elf information about a module. Copy the Elf header,

 * section header table, section string table, and symtab section

 * index from info to mod->klp_info.

 */

int copy_module_elf(struct module *mod, struct load_info *info)

{

	unsigned int size, symndx;

	int ret;



	size = sizeof(*mod->klp_info);

	mod->klp_info = kmalloc(size, GFP_KERNEL);

	if (!mod->klp_info)

		return -ENOMEM;



	/* Elf header */

	size = sizeof(mod->klp_info->hdr);

	memcpy(&mod->klp_info->hdr, info->hdr, size);



	/* Elf section header table */

	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;

	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);

	if (!mod->klp_info->sechdrs) {

		ret = -ENOMEM;

		goto free_info;

	}



	/* Elf section name string table */

	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;

	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);

	if (!mod->klp_info->secstrings) {

		ret = -ENOMEM;

		goto free_sechdrs;

	}



	/* Elf symbol section index */

	symndx = info->index.sym;

	mod->klp_info->symndx = symndx;



	/*

	 * For livepatch modules, core_kallsyms.symtab is a complete

	 * copy of the original symbol table. Adjust sh_addr to point

	 * to core_kallsyms.symtab since the copy of the symtab in module

	 * init memory is freed at the end of do_init_module().

	 */

	mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long)mod->core_kallsyms.symtab;



	return 0;



free_sechdrs:

	kfree(mod->klp_info->sechdrs);

free_info:

	kfree(mod->klp_info);

	return ret;

}



void free_module_elf(struct module *mod)

{

	kfree(mod->klp_info->sechdrs);

	kfree(mod->klp_info->secstrings);

	kfree(mod->klp_info);

}