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