// 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 <linux/execmem.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) {		const struct module_memory *mem = &mod->mem[type];		int ret; 		if (mem->is_rox)			ret = execmem_restore_rox(mem->base, mem->size);		else 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(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,				const char *secstrings,				const 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;} static const char *const ro_after_init[] = {	/*	 * Section .data..ro_after_init holds data explicitly annotated by	 * __ro_after_init.	 */	".data..ro_after_init", 	/*	 * Section __jump_table holds data structures that are never modified,	 * with the exception of entries that refer to code in the __init	 * section, which are marked as such at module load time.	 */	"__jump_table", #ifdef CONFIG_HAVE_STATIC_CALL_INLINE	/*	 * Section .static_call_sites holds data structures that need to be	 * sorted and processed at module load time but are never modified	 * afterwards.	 */	".static_call_sites",#endif}; void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs,			       const char *secstrings){	int i, j; 	for (i = 1; i < hdr->e_shnum; i++) {		Elf_Shdr *shdr = &sechdrs[i]; 		for (j = 0; j < ARRAY_SIZE(ro_after_init); j++) {			if (strcmp(secstrings + shdr->sh_name,				   ro_after_init[j]) == 0) {				shdr->sh_flags |= SHF_RO_AFTER_INIT;				break;			}		}	}}