linux-next/kernel/module/strict_rwx.c
Christophe Leroy 570f7776db module: Split module_enable_rodata_ro()
module_enable_rodata_ro() is called twice, once before module init
to set rodata sections readonly and once after module init to set
rodata_after_init section readonly.

The second time, only the rodata_after_init section needs to be
set to read-only, no need to re-apply it to already set rodata.

Split module_enable_rodata_ro() in two.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Daniel Gomez <da.gomez@samsung.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/e3b6ff0df7eac281c58bb02cecaeb377215daff3.1733427536.git.christophe.leroy@csgroup.eu
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
2025-01-13 11:53:14 +01:00

108 lines
2.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Module strict rwx
*
* Copyright (C) 2015 Rusty Russell
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/set_memory.h>
#include "internal.h"
static int module_set_memory(const struct module *mod, enum mod_mem_type type,
int (*set_memory)(unsigned long start, int num_pages))
{
const struct module_memory *mod_mem = &mod->mem[type];
if (!mod_mem->base)
return 0;
set_vm_flush_reset_perms(mod_mem->base);
return set_memory((unsigned long)mod_mem->base, mod_mem->size >> PAGE_SHIFT);
}
/*
* Since some arches are moving towards PAGE_KERNEL module allocations instead
* of PAGE_KERNEL_EXEC, keep module_enable_x() independent of
* CONFIG_STRICT_MODULE_RWX because they are needed regardless of whether we
* are strict.
*/
int module_enable_text_rox(const struct module *mod)
{
for_class_mod_mem_type(type, text) {
int ret;
if (mod->mem[type].is_rox)
continue;
if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
ret = module_set_memory(mod, type, set_memory_rox);
else
ret = module_set_memory(mod, type, set_memory_x);
if (ret)
return ret;
}
return 0;
}
int module_enable_rodata_ro(const struct module *mod)
{
int ret;
if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX) || !rodata_enabled)
return 0;
ret = module_set_memory(mod, MOD_RODATA, set_memory_ro);
if (ret)
return ret;
ret = module_set_memory(mod, MOD_INIT_RODATA, set_memory_ro);
if (ret)
return ret;
return 0;
}
int module_enable_rodata_ro_after_init(const struct module *mod)
{
if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX) || !rodata_enabled)
return 0;
return module_set_memory(mod, MOD_RO_AFTER_INIT, set_memory_ro);
}
int module_enable_data_nx(const struct module *mod)
{
if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
return 0;
for_class_mod_mem_type(type, data) {
int ret = module_set_memory(mod, type, set_memory_nx);
if (ret)
return ret;
}
return 0;
}
int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
char *secstrings, struct module *mod)
{
const unsigned long shf_wx = SHF_WRITE | SHF_EXECINSTR;
int i;
if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
return 0;
for (i = 0; i < hdr->e_shnum; i++) {
if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) {
pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n",
mod->name, secstrings + sechdrs[i].sh_name, i);
return -ENOEXEC;
}
}
return 0;
}