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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152// 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; } } }}