diff options
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 76 |
1 files changed, 48 insertions, 28 deletions
diff --git a/kernel/module.c b/kernel/module.c index be5413903d20..ef400c389f49 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1946,7 +1946,6 @@ static void mod_sysfs_teardown(struct module *mod) mod_sysfs_fini(mod); } -#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX /* * LKM RO/NX protection: protect module's text/ro-data * from modification and any data from execution. @@ -1960,6 +1959,14 @@ static void mod_sysfs_teardown(struct module *mod) * * These values are always page-aligned (as is base) */ + +/* + * Since some arches are moving towards PAGE_KERNEL module allocations instead + * of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the + * CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of + * whether we are strict. + */ +#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX static void frob_text(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages)) { @@ -1969,6 +1976,15 @@ static void frob_text(const struct module_layout *layout, layout->text_size >> PAGE_SHIFT); } +static void module_enable_x(const struct module *mod) +{ + frob_text(&mod->core_layout, set_memory_x); + frob_text(&mod->init_layout, set_memory_x); +} +#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ +static void module_enable_x(const struct module *mod) { } +#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ + #ifdef CONFIG_STRICT_MODULE_RWX static void frob_rodata(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages)) @@ -2000,20 +2016,7 @@ static void frob_writable_data(const struct module_layout *layout, (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT); } -/* livepatching wants to disable read-only so it can frob module. */ -void module_disable_ro(const struct module *mod) -{ - if (!rodata_enabled) - return; - - frob_text(&mod->core_layout, set_memory_rw); - frob_rodata(&mod->core_layout, set_memory_rw); - frob_ro_after_init(&mod->core_layout, set_memory_rw); - frob_text(&mod->init_layout, set_memory_rw); - frob_rodata(&mod->init_layout, set_memory_rw); -} - -void module_enable_ro(const struct module *mod, bool after_init) +static void module_enable_ro(const struct module *mod, bool after_init) { if (!rodata_enabled) return; @@ -2039,19 +2042,29 @@ static void module_enable_nx(const struct module *mod) frob_writable_data(&mod->init_layout, set_memory_nx); } +static 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; + + for (i = 0; i < hdr->e_shnum; i++) { + if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) + return -ENOEXEC; + } + + return 0; +} + #else /* !CONFIG_STRICT_MODULE_RWX */ static void module_enable_nx(const struct module *mod) { } -#endif /* CONFIG_STRICT_MODULE_RWX */ -static void module_enable_x(const struct module *mod) +static void module_enable_ro(const struct module *mod, bool after_init) {} +static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, + char *secstrings, struct module *mod) { - frob_text(&mod->core_layout, set_memory_x); - frob_text(&mod->init_layout, set_memory_x); + return 0; } -#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ -static void module_enable_nx(const struct module *mod) { } -static void module_enable_x(const struct module *mod) { } -#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ - +#endif /* CONFIG_STRICT_MODULE_RWX */ #ifdef CONFIG_LIVEPATCH /* @@ -2337,11 +2350,13 @@ static int apply_relocations(struct module *mod, const struct load_info *info) if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC)) continue; - /* Livepatch relocation sections are applied by livepatch */ if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH) - continue; - - if (info->sechdrs[i].sh_type == SHT_REL) + err = klp_apply_section_relocs(mod, info->sechdrs, + info->secstrings, + info->strtab, + info->index.sym, i, + NULL); + else if (info->sechdrs[i].sh_type == SHT_REL) err = apply_relocate(info->sechdrs, info->strtab, info->index.sym, i, mod); else if (info->sechdrs[i].sh_type == SHT_RELA) @@ -3395,6 +3410,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) if (err < 0) return ERR_PTR(err); + err = module_enforce_rwx_sections(info->hdr, info->sechdrs, + info->secstrings, info->mod); + if (err < 0) + return ERR_PTR(err); + /* We will do a special allocation for per-cpu sections later. */ info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC; |