diff options
Diffstat (limited to 'kernel/module')
| -rw-r--r-- | kernel/module/Kconfig | 5 | ||||
| -rw-r--r-- | kernel/module/internal.h | 18 | ||||
| -rw-r--r-- | kernel/module/kallsyms.c | 73 | ||||
| -rw-r--r-- | kernel/module/main.c | 321 | ||||
| -rw-r--r-- | kernel/module/strict_rwx.c | 56 | ||||
| -rw-r--r-- | kernel/module/tracking.c | 2 | ||||
| -rw-r--r-- | kernel/module/tree_lookup.c | 8 | ||||
| -rw-r--r-- | kernel/module/version.c | 14 |
8 files changed, 269 insertions, 228 deletions
diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig index d7762ef5949a..39278737bb68 100644 --- a/kernel/module/Kconfig +++ b/kernel/module/Kconfig @@ -192,6 +192,11 @@ config GENDWARFKSYMS depends on !DEBUG_INFO_REDUCED && !DEBUG_INFO_SPLIT # Requires ELF object files. depends on !LTO + # To avoid conflicts with the discarded __gendwarfksyms_ptr symbols on + # X86, requires pahole before commit 47dcb534e253 ("btf_encoder: Stop + # indexing symbols for VARs") or after commit 9810758003ce ("btf_encoder: + # Verify 0 address DWARF variables are in ELF section"). + depends on !X86 || !DEBUG_INFO_BTF || PAHOLE_VERSION < 128 || PAHOLE_VERSION > 129 help Calculate symbol versions from DWARF debugging information using gendwarfksyms. Requires DEBUG_INFO to be enabled. diff --git a/kernel/module/internal.h b/kernel/module/internal.h index d09b46ef032f..8d74b0a21c82 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -124,17 +124,6 @@ char *module_next_tag_pair(char *string, unsigned long *secsize); #define for_each_modinfo_entry(entry, info, name) \ for (entry = get_modinfo(info, name); entry; entry = get_next_modinfo(info, name, entry)) -static inline void module_assert_mutex_or_preempt(void) -{ -#ifdef CONFIG_LOCKDEP - if (unlikely(!debug_locks)) - return; - - WARN_ON_ONCE(!rcu_read_lock_sched_held() && - !lockdep_is_held(&module_mutex)); -#endif -} - static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym) { #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS @@ -333,8 +322,11 @@ int module_enable_rodata_ro(const struct module *mod); int module_enable_rodata_ro_after_init(const struct module *mod); int module_enable_data_nx(const struct module *mod); int module_enable_text_rox(const struct module *mod); -int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, - char *secstrings, struct module *mod); +int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, + const char *secstrings, + const struct module *mod); +void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs, + const char *secstrings); #ifdef CONFIG_MODULE_SIG int module_sig_check(struct load_info *info, int flags); diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c index bf65e0c3c86f..00a60796327c 100644 --- a/kernel/module/kallsyms.c +++ b/kernel/module/kallsyms.c @@ -177,19 +177,15 @@ void add_kallsyms(struct module *mod, const struct load_info *info) unsigned long strtab_size; void *data_base = mod->mem[MOD_DATA].base; void *init_data_base = mod->mem[MOD_INIT_DATA].base; + struct mod_kallsyms *kallsyms; - /* Set up to point into init section. */ - mod->kallsyms = (void __rcu *)init_data_base + - info->mod_kallsyms_init_off; + kallsyms = init_data_base + info->mod_kallsyms_init_off; - rcu_read_lock(); - /* The following is safe since this pointer cannot change */ - rcu_dereference(mod->kallsyms)->symtab = (void *)symsec->sh_addr; - rcu_dereference(mod->kallsyms)->num_symtab = symsec->sh_size / sizeof(Elf_Sym); + kallsyms->symtab = (void *)symsec->sh_addr; + kallsyms->num_symtab = symsec->sh_size / sizeof(Elf_Sym); /* Make sure we get permanent strtab: don't use info->strtab. */ - rcu_dereference(mod->kallsyms)->strtab = - (void *)info->sechdrs[info->index.str].sh_addr; - rcu_dereference(mod->kallsyms)->typetab = init_data_base + info->init_typeoffs; + kallsyms->strtab = (void *)info->sechdrs[info->index.str].sh_addr; + kallsyms->typetab = init_data_base + info->init_typeoffs; /* * Now populate the cut down core kallsyms for after init @@ -199,20 +195,19 @@ void add_kallsyms(struct module *mod, const struct load_info *info) mod->core_kallsyms.strtab = s = data_base + info->stroffs; mod->core_kallsyms.typetab = data_base + info->core_typeoffs; strtab_size = info->core_typeoffs - info->stroffs; - src = rcu_dereference(mod->kallsyms)->symtab; - for (ndst = i = 0; i < rcu_dereference(mod->kallsyms)->num_symtab; i++) { - rcu_dereference(mod->kallsyms)->typetab[i] = elf_type(src + i, info); + src = kallsyms->symtab; + for (ndst = i = 0; i < kallsyms->num_symtab; i++) { + kallsyms->typetab[i] = elf_type(src + i, info); if (i == 0 || is_livepatch_module(mod) || is_core_symbol(src + i, info->sechdrs, info->hdr->e_shnum, info->index.pcpu)) { ssize_t ret; mod->core_kallsyms.typetab[ndst] = - rcu_dereference(mod->kallsyms)->typetab[i]; + kallsyms->typetab[i]; dst[ndst] = src[i]; dst[ndst++].st_name = s - mod->core_kallsyms.strtab; - ret = strscpy(s, - &rcu_dereference(mod->kallsyms)->strtab[src[i].st_name], + ret = strscpy(s, &kallsyms->strtab[src[i].st_name], strtab_size); if (ret < 0) break; @@ -220,7 +215,9 @@ void add_kallsyms(struct module *mod, const struct load_info *info) strtab_size -= ret + 1; } } - rcu_read_unlock(); + + /* Set up to point into init section. */ + rcu_assign_pointer(mod->kallsyms, kallsyms); mod->core_kallsyms.num_symtab = ndst; } @@ -260,7 +257,7 @@ static const char *find_kallsyms_symbol(struct module *mod, { unsigned int i, best = 0; unsigned long nextval, bestval; - struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms); + struct mod_kallsyms *kallsyms = rcu_dereference(mod->kallsyms); struct module_memory *mod_mem; /* At worse, next value is at end of module */ @@ -319,7 +316,7 @@ void * __weak dereference_module_function_descriptor(struct module *mod, /* * For kallsyms to ask for address resolution. NULL means not found. Careful - * not to lock to avoid deadlock on oopses, simply disable preemption. + * not to lock to avoid deadlock on oopses, RCU is enough. */ int module_address_lookup(unsigned long addr, unsigned long *size, @@ -332,7 +329,7 @@ int module_address_lookup(unsigned long addr, int ret = 0; struct module *mod; - preempt_disable(); + guard(rcu)(); mod = __module_address(addr); if (mod) { if (modname) @@ -350,8 +347,6 @@ int module_address_lookup(unsigned long addr, if (sym) ret = strscpy(namebuf, sym, KSYM_NAME_LEN); } - preempt_enable(); - return ret; } @@ -359,7 +354,7 @@ int lookup_module_symbol_name(unsigned long addr, char *symname) { struct module *mod; - preempt_disable(); + guard(rcu)(); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; @@ -371,12 +366,10 @@ int lookup_module_symbol_name(unsigned long addr, char *symname) goto out; strscpy(symname, sym, KSYM_NAME_LEN); - preempt_enable(); return 0; } } out: - preempt_enable(); return -ERANGE; } @@ -385,13 +378,13 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, { struct module *mod; - preempt_disable(); + guard(rcu)(); list_for_each_entry_rcu(mod, &modules, list) { struct mod_kallsyms *kallsyms; if (mod->state == MODULE_STATE_UNFORMED) continue; - kallsyms = rcu_dereference_sched(mod->kallsyms); + kallsyms = rcu_dereference(mod->kallsyms); if (symnum < kallsyms->num_symtab) { const Elf_Sym *sym = &kallsyms->symtab[symnum]; @@ -400,12 +393,10 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, strscpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN); strscpy(module_name, mod->name, MODULE_NAME_LEN); *exported = is_exported(name, *value, mod); - preempt_enable(); return 0; } symnum -= kallsyms->num_symtab; } - preempt_enable(); return -ERANGE; } @@ -413,7 +404,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, static unsigned long __find_kallsyms_symbol_value(struct module *mod, const char *name) { unsigned int i; - struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms); + struct mod_kallsyms *kallsyms = rcu_dereference(mod->kallsyms); for (i = 0; i < kallsyms->num_symtab; i++) { const Elf_Sym *sym = &kallsyms->symtab[i]; @@ -453,23 +444,15 @@ static unsigned long __module_kallsyms_lookup_name(const char *name) /* Look for this name: can be of form module:name. */ unsigned long module_kallsyms_lookup_name(const char *name) { - unsigned long ret; - /* Don't lock: we're in enough trouble already. */ - preempt_disable(); - ret = __module_kallsyms_lookup_name(name); - preempt_enable(); - return ret; + guard(rcu)(); + return __module_kallsyms_lookup_name(name); } unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name) { - unsigned long ret; - - preempt_disable(); - ret = __find_kallsyms_symbol_value(mod, name); - preempt_enable(); - return ret; + guard(rcu)(); + return __find_kallsyms_symbol_value(mod, name); } int module_kallsyms_on_each_symbol(const char *modname, @@ -490,10 +473,8 @@ int module_kallsyms_on_each_symbol(const char *modname, if (modname && strcmp(modname, mod->name)) continue; - /* Use rcu_dereference_sched() to remain compliant with the sparse tool */ - preempt_disable(); - kallsyms = rcu_dereference_sched(mod->kallsyms); - preempt_enable(); + kallsyms = rcu_dereference_check(mod->kallsyms, + lockdep_is_held(&module_mutex)); for (i = 0; i < kallsyms->num_symtab; i++) { const Elf_Sym *sym = &kallsyms->symtab[i]; diff --git a/kernel/module/main.c b/kernel/module/main.c index 1fb9ad289a6f..413ac6ea3702 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -67,7 +67,7 @@ /* * Mutex protects: - * 1) List of modules (also safely readable with preempt_disable), + * 1) List of modules (also safely readable within RCU read section), * 2) module_use links, * 3) mod_tree.addr_min/mod_tree.addr_max. * (delete and add uses RCU list operations). @@ -170,6 +170,30 @@ static inline void add_taint_module(struct module *mod, unsigned flag, } /* + * Like strncmp(), except s/-/_/g as per scripts/Makefile.lib:name-fix-token rule. + */ +static int mod_strncmp(const char *str_a, const char *str_b, size_t n) +{ + for (int i = 0; i < n; i++) { + char a = str_a[i]; + char b = str_b[i]; + int d; + + if (a == '-') a = '_'; + if (b == '-') b = '_'; + + d = a - b; + if (d) + return d; + + if (!a) + break; + } + + return 0; +} + +/* * A thread that wants to hold a reference to a module only while it * is running can call this to safely exit. */ @@ -331,7 +355,7 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms, /* * Find an exported symbol and return it, along with, (optional) crc and - * (optional) module which owns it. Needs preempt disabled or module_mutex. + * (optional) module which owns it. Needs RCU or module_mutex. */ bool find_symbol(struct find_symbol_arg *fsa) { @@ -345,8 +369,6 @@ bool find_symbol(struct find_symbol_arg *fsa) struct module *mod; unsigned int i; - module_assert_mutex_or_preempt(); - for (i = 0; i < ARRAY_SIZE(arr); i++) if (find_exported_symbol_in_section(&arr[i], NULL, fsa)) return true; @@ -374,16 +396,14 @@ bool find_symbol(struct find_symbol_arg *fsa) } /* - * Search for module by name: must hold module_mutex (or preempt disabled - * for read-only access). + * Search for module by name: must hold module_mutex (or RCU for read-only + * access). */ struct module *find_module_all(const char *name, size_t len, bool even_unformed) { struct module *mod; - module_assert_mutex_or_preempt(); - list_for_each_entry_rcu(mod, &modules, list, lockdep_is_held(&module_mutex)) { if (!even_unformed && mod->state == MODULE_STATE_UNFORMED) @@ -454,8 +474,7 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr) struct module *mod; unsigned int cpu; - preempt_disable(); - + guard(rcu)(); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; @@ -472,13 +491,10 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr) per_cpu_ptr(mod->percpu, get_boot_cpu_id()); } - preempt_enable(); return true; } } } - - preempt_enable(); return false; } @@ -795,8 +811,8 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, async_synchronize_full(); /* Store the name and taints of the last unloaded module for diagnostic purposes */ - strscpy(last_unloaded_module.name, mod->name, sizeof(last_unloaded_module.name)); - strscpy(last_unloaded_module.taints, module_flags(mod, buf, false), sizeof(last_unloaded_module.taints)); + strscpy(last_unloaded_module.name, mod->name); + strscpy(last_unloaded_module.taints, module_flags(mod, buf, false)); free_module(mod); /* someone could wait for the module in add_unformed_module() */ @@ -814,10 +830,9 @@ void __symbol_put(const char *symbol) .gplok = true, }; - preempt_disable(); + guard(rcu)(); BUG_ON(!find_symbol(&fsa)); module_put(fsa.owner); - preempt_enable(); } EXPORT_SYMBOL(__symbol_put); @@ -832,13 +847,12 @@ void symbol_put_addr(void *addr) /* * Even though we hold a reference on the module; we still need to - * disable preemption in order to safely traverse the data structure. + * RCU read section in order to safely traverse the data structure. */ - preempt_disable(); + guard(rcu)(); modaddr = __module_text_address(a); BUG_ON(!modaddr); module_put(modaddr); - preempt_enable(); } EXPORT_SYMBOL_GPL(symbol_put_addr); @@ -1093,6 +1107,46 @@ static char *get_modinfo(const struct load_info *info, const char *tag) return get_next_modinfo(info, tag, NULL); } +/** + * verify_module_namespace() - does @modname have access to this symbol's @namespace + * @namespace: export symbol namespace + * @modname: module name + * + * If @namespace is prefixed with "module:" to indicate it is a module namespace + * then test if @modname matches any of the comma separated patterns. + * + * The patterns only support tail-glob. + */ +static bool verify_module_namespace(const char *namespace, const char *modname) +{ + size_t len, modlen = strlen(modname); + const char *prefix = "module:"; + const char *sep; + bool glob; + + if (!strstarts(namespace, prefix)) + return false; + + for (namespace += strlen(prefix); *namespace; namespace = sep) { + sep = strchrnul(namespace, ','); + len = sep - namespace; + + glob = false; + if (sep[-1] == '*') { + len--; + glob = true; + } + + if (*sep) + sep++; + + if (mod_strncmp(namespace, modname, len) == 0 && (glob || len == modlen)) + return true; + } + + return false; +} + static int verify_namespace_is_imported(const struct load_info *info, const struct kernel_symbol *sym, struct module *mod) @@ -1102,6 +1156,10 @@ static int verify_namespace_is_imported(const struct load_info *info, namespace = kernel_symbol_namespace(sym); if (namespace && namespace[0]) { + + if (verify_module_namespace(namespace, mod->name)) + return 0; + for_each_modinfo_entry(imported_namespace, info, "import_ns") { if (strcmp(namespace, imported_namespace) == 0) return 0; @@ -1189,7 +1247,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod, getname: /* We must make copy under the lock if we failed to get ref. */ - strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN); + strscpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN); unlock: mutex_unlock(&module_mutex); return fsa.sym; @@ -1221,18 +1279,6 @@ void __weak module_arch_freeing_init(struct module *mod) { } -void *__module_writable_address(struct module *mod, void *loc) -{ - for_class_mod_mem_type(type, text) { - struct module_memory *mem = &mod->mem[type]; - - if (loc >= mem->base && loc < mem->base + mem->size) - return loc + (mem->rw_copy - mem->base); - } - - return loc; -} - static int module_memory_alloc(struct module *mod, enum mod_mem_type type) { unsigned int size = PAGE_ALIGN(mod->mem[type].size); @@ -1250,21 +1296,15 @@ static int module_memory_alloc(struct module *mod, enum mod_mem_type type) if (!ptr) return -ENOMEM; - mod->mem[type].base = ptr; - if (execmem_is_rox(execmem_type)) { - ptr = vzalloc(size); + int err = execmem_make_temp_rw(ptr, size); - if (!ptr) { - execmem_free(mod->mem[type].base); + if (err) { + execmem_free(ptr); return -ENOMEM; } - mod->mem[type].rw_copy = ptr; mod->mem[type].is_rox = true; - } else { - mod->mem[type].rw_copy = mod->mem[type].base; - memset(mod->mem[type].base, 0, size); } /* @@ -1278,18 +1318,29 @@ static int module_memory_alloc(struct module *mod, enum mod_mem_type type) * *do* eventually get freed, but let's just keep things simple * and avoid *any* false positives. */ - kmemleak_not_leak(ptr); + if (!mod->mem[type].is_rox) + kmemleak_not_leak(ptr); + + memset(ptr, 0, size); + mod->mem[type].base = ptr; return 0; } +static void module_memory_restore_rox(struct module *mod) +{ + for_class_mod_mem_type(type, text) { + struct module_memory *mem = &mod->mem[type]; + + if (mem->is_rox) + execmem_restore_rox(mem->base, mem->size); + } +} + static void module_memory_free(struct module *mod, enum mod_mem_type type) { struct module_memory *mem = &mod->mem[type]; - if (mem->is_rox) - vfree(mem->rw_copy); - execmem_free(mem->base); } @@ -1348,7 +1399,7 @@ static void free_module(struct module *mod) mod_tree_remove(mod); /* Remove this module from bug list, this uses list_del_rcu */ module_bug_cleanup(mod); - /* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */ + /* Wait for RCU synchronizing before releasing mod->list and buglist. */ synchronize_rcu(); if (try_add_tainted_module(mod)) pr_err("%s: adding tainted module to the unloaded tainted modules list failed.\n", @@ -1371,21 +1422,18 @@ void *__symbol_get(const char *symbol) .warn = true, }; - preempt_disable(); - if (!find_symbol(&fsa)) - goto fail; - if (fsa.license != GPL_ONLY) { - pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n", - symbol); - goto fail; + scoped_guard(rcu) { + if (!find_symbol(&fsa)) + return NULL; + if (fsa.license != GPL_ONLY) { + pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n", + symbol); + return NULL; + } + if (strong_try_module_get(fsa.owner)) + return NULL; } - if (strong_try_module_get(fsa.owner)) - goto fail; - preempt_enable(); return (void *)kernel_symbol_value(fsa.sym); -fail: - preempt_enable(); - return NULL; } EXPORT_SYMBOL_GPL(__symbol_get); @@ -1582,12 +1630,11 @@ static void __layout_sections(struct module *mod, struct load_info *info, bool i { unsigned int m, i; + /* + * { Mask of required section header flags, + * Mask of excluded section header flags } + */ static const unsigned long masks[][2] = { - /* - * NOTE: all executable code must be the first section - * in this array; otherwise modify the text_size - * finder in the two loops below - */ { SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL }, { SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL }, { SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL }, @@ -1679,15 +1726,30 @@ static void module_license_taint_check(struct module *mod, const char *license) } } -static void setup_modinfo(struct module *mod, struct load_info *info) +static int setup_modinfo(struct module *mod, struct load_info *info) { const struct module_attribute *attr; + char *imported_namespace; int i; for (i = 0; (attr = modinfo_attrs[i]); i++) { if (attr->setup) attr->setup(mod, get_modinfo(info, attr->attr.name)); } + + for_each_modinfo_entry(imported_namespace, info, "import_ns") { + /* + * 'module:' prefixed namespaces are implicit, disallow + * explicit imports. + */ + if (strstarts(imported_namespace, "module:")) { + pr_err("%s: module tries to import module namespace: %s\n", + mod->name, imported_namespace); + return -EPERM; + } + } + + return 0; } static void free_modinfo(struct module *mod) @@ -2642,7 +2704,6 @@ static int move_module(struct module *mod, struct load_info *info) for_each_mod_mem_type(type) { if (!mod->mem[type].size) { mod->mem[type].base = NULL; - mod->mem[type].rw_copy = NULL; continue; } @@ -2659,7 +2720,6 @@ static int move_module(struct module *mod, struct load_info *info) void *dest; Elf_Shdr *shdr = &info->sechdrs[i]; const char *sname; - unsigned long addr; if (!(shdr->sh_flags & SHF_ALLOC)) continue; @@ -2680,14 +2740,12 @@ static int move_module(struct module *mod, struct load_info *info) ret = PTR_ERR(dest); goto out_err; } - addr = (unsigned long)dest; codetag_section_found = true; } else { enum mod_mem_type type = shdr->sh_entsize >> SH_ENTSIZE_TYPE_SHIFT; unsigned long offset = shdr->sh_entsize & SH_ENTSIZE_OFFSET_MASK; - addr = (unsigned long)mod->mem[type].base + offset; - dest = mod->mem[type].rw_copy + offset; + dest = mod->mem[type].base + offset; } if (shdr->sh_type != SHT_NOBITS) { @@ -2710,13 +2768,14 @@ static int move_module(struct module *mod, struct load_info *info) * users of info can keep taking advantage and using the newly * minted official memory area. */ - shdr->sh_addr = addr; + shdr->sh_addr = (unsigned long)dest; pr_debug("\t0x%lx 0x%.8lx %s\n", (long)shdr->sh_addr, (long)shdr->sh_size, info->secstrings + shdr->sh_name); } return 0; out_err: + module_memory_restore_rox(mod); for (t--; t >= 0; t--) module_memory_free(mod, t); if (codetag_section_found) @@ -2791,7 +2850,6 @@ core_param(module_blacklist, module_blacklist, charp, 0400); static struct module *layout_and_allocate(struct load_info *info, int flags) { struct module *mod; - unsigned int ndx; int err; /* Allow arches to frob section contents and sizes. */ @@ -2809,22 +2867,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC; /* - * Mark ro_after_init section with SHF_RO_AFTER_INIT so that - * layout_sections() can put it in the right place. + * Mark relevant sections as SHF_RO_AFTER_INIT so layout_sections() can + * put them in the right place. * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set. */ - ndx = find_sec(info, ".data..ro_after_init"); - if (ndx) - info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT; - /* - * Mark the __jump_table section as ro_after_init as well: these data - * structures are never modified, with the exception of entries that - * refer to code in the __init section, which are annotated as such - * at module load time. - */ - ndx = find_sec(info, "__jump_table"); - if (ndx) - info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT; + module_mark_ro_after_init(info->hdr, info->sechdrs, info->secstrings); /* * Determine total sizes, and put offsets in sh_entsize. For now @@ -2852,6 +2899,7 @@ static void module_deallocate(struct module *mod, struct load_info *info) { percpu_modfree(mod); module_arch_freeing_init(mod); + codetag_free_module_sections(mod); free_mod_mem(mod); } @@ -2863,17 +2911,8 @@ int __weak module_finalize(const Elf_Ehdr *hdr, return 0; } -int __weak module_post_finalize(const Elf_Ehdr *hdr, - const Elf_Shdr *sechdrs, - struct module *me) -{ - return 0; -} - static int post_relocation(struct module *mod, const struct load_info *info) { - int ret; - /* Sort exception table now relocations are done. */ sort_extable(mod->extable, mod->extable + mod->num_exentries); @@ -2885,24 +2924,7 @@ static int post_relocation(struct module *mod, const struct load_info *info) add_kallsyms(mod, info); /* Arch-specific module finalizing. */ - ret = module_finalize(info->hdr, info->sechdrs, mod); - if (ret) - return ret; - - for_each_mod_mem_type(type) { - struct module_memory *mem = &mod->mem[type]; - - if (mem->is_rox) { - if (!execmem_update_copy(mem->base, mem->rw_copy, - mem->size)) - return -ENOMEM; - - vfree(mem->rw_copy); - mem->rw_copy = NULL; - } - } - - return module_post_finalize(info->hdr, info->sechdrs, mod); + return module_finalize(info->hdr, info->sechdrs, mod); } /* Call module constructors. */ @@ -3049,7 +3071,7 @@ static noinline int do_init_module(struct module *mod) #endif /* * We want to free module_init, but be aware that kallsyms may be - * walking this with preempt disabled. In all the failure paths, we + * walking this within an RCU read section. In all the failure paths, we * call synchronize_rcu(), but we don't want to slow down the success * path. execmem_free() cannot be called in an interrupt, so do the * work and call synchronize_rcu() in a work queue. @@ -3384,7 +3406,9 @@ static int load_module(struct load_info *info, const char __user *uargs, goto free_unload; /* Set up MODINFO_ATTR fields */ - setup_modinfo(mod, info); + err = setup_modinfo(mod, info); + if (err) + goto free_modinfo; /* Fix up syms, so that st_value is a pointer to location. */ err = simplify_symbols(mod, info); @@ -3447,11 +3471,12 @@ static int load_module(struct load_info *info, const char __user *uargs, goto sysfs_cleanup; } + if (codetag_load_module(mod)) + goto sysfs_cleanup; + /* Get rid of temporary copy. */ free_copy(info, flags); - codetag_load_module(mod); - /* Done! */ trace_module_load(mod); @@ -3499,6 +3524,7 @@ static int load_module(struct load_info *info, const char __user *uargs, mod->mem[type].size); } + module_memory_restore_rox(mod); module_deallocate(mod, info); free_copy: /* @@ -3715,28 +3741,23 @@ out: /* Given an address, look for it in the module exception tables. */ const struct exception_table_entry *search_module_extables(unsigned long addr) { - const struct exception_table_entry *e = NULL; struct module *mod; - preempt_disable(); + guard(rcu)(); mod = __module_address(addr); if (!mod) - goto out; + return NULL; if (!mod->num_exentries) - goto out; - - e = search_extable(mod->extable, - mod->num_exentries, - addr); -out: - preempt_enable(); - + return NULL; /* - * Now, if we found one, we are running inside it now, hence - * we cannot unload the module, hence no refcnt needed. + * The address passed here belongs to a module that is currently + * invoked (we are running inside it). Therefore its module::refcnt + * needs already be >0 to ensure that it is not removed at this stage. + * All other user need to invoke this function within a RCU read + * section. */ - return e; + return search_extable(mod->extable, mod->num_exentries, addr); } /** @@ -3748,20 +3769,15 @@ out: */ bool is_module_address(unsigned long addr) { - bool ret; - - preempt_disable(); - ret = __module_address(addr) != NULL; - preempt_enable(); - - return ret; + guard(rcu)(); + return __module_address(addr) != NULL; } /** * __module_address() - get the module which contains an address. * @addr: the address. * - * Must be called with preempt disabled or module mutex held so that + * Must be called within RCU read section or module mutex held so that * module doesn't get freed during this. */ struct module *__module_address(unsigned long addr) @@ -3779,8 +3795,6 @@ struct module *__module_address(unsigned long addr) return NULL; lookup: - module_assert_mutex_or_preempt(); - mod = mod_find(addr, &mod_tree); if (mod) { BUG_ON(!within_module(addr, mod)); @@ -3800,20 +3814,28 @@ lookup: */ bool is_module_text_address(unsigned long addr) { - bool ret; + guard(rcu)(); + return __module_text_address(addr) != NULL; +} - preempt_disable(); - ret = __module_text_address(addr) != NULL; - preempt_enable(); +void module_for_each_mod(int(*func)(struct module *mod, void *data), void *data) +{ + struct module *mod; - return ret; + guard(rcu)(); + list_for_each_entry_rcu(mod, &modules, list) { + if (mod->state == MODULE_STATE_UNFORMED) + continue; + if (func(mod, data)) + break; + } } /** * __module_text_address() - get the module whose code contains an address. * @addr: the address. * - * Must be called with preempt disabled or module mutex held so that + * Must be called within RCU read section or module mutex held so that * module doesn't get freed during this. */ struct module *__module_text_address(unsigned long addr) @@ -3836,7 +3858,7 @@ void print_modules(void) printk(KERN_DEFAULT "Modules linked in:"); /* Most callers should already have preempt disabled, but make sure */ - preempt_disable(); + guard(rcu)(); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; @@ -3844,7 +3866,6 @@ void print_modules(void) } print_unloaded_tainted_modules(); - preempt_enable(); if (last_unloaded_module.name[0]) pr_cont(" [last unloaded: %s%s]", last_unloaded_module.name, last_unloaded_module.taints); diff --git a/kernel/module/strict_rwx.c b/kernel/module/strict_rwx.c index 74834ba15615..8fd438529fbc 100644 --- a/kernel/module/strict_rwx.c +++ b/kernel/module/strict_rwx.c @@ -9,6 +9,7 @@ #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, @@ -32,12 +33,12 @@ static int module_set_memory(const struct module *mod, enum mod_mem_type type, 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 (mod->mem[type].is_rox) - continue; - - if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) + 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); @@ -86,8 +87,9 @@ int module_enable_data_nx(const struct module *mod) return 0; } -int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, - char *secstrings, struct module *mod) +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; @@ -105,3 +107,45 @@ int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 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; + } + } + } +} diff --git a/kernel/module/tracking.c b/kernel/module/tracking.c index 16742d1c630c..4fefec5b683c 100644 --- a/kernel/module/tracking.c +++ b/kernel/module/tracking.c @@ -21,8 +21,6 @@ int try_add_tainted_module(struct module *mod) { struct mod_unload_taint *mod_taint; - module_assert_mutex_or_preempt(); - if (!mod->taints) goto out; diff --git a/kernel/module/tree_lookup.c b/kernel/module/tree_lookup.c index 277197977d43..d3204c5c74eb 100644 --- a/kernel/module/tree_lookup.c +++ b/kernel/module/tree_lookup.c @@ -12,11 +12,11 @@ /* * Use a latched RB-tree for __module_address(); this allows us to use - * RCU-sched lookups of the address from any context. + * RCU lookups of the address from any context. * - * This is conditional on PERF_EVENTS || TRACING because those can really hit - * __module_address() hard by doing a lot of stack unwinding; potentially from - * NMI context. + * This is conditional on PERF_EVENTS || TRACING || CFI_CLANG because those can + * really hit __module_address() hard by doing a lot of stack unwinding; + * potentially from NMI context. */ static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n) diff --git a/kernel/module/version.c b/kernel/module/version.c index 3718a8868321..2beefeba82d9 100644 --- a/kernel/module/version.c +++ b/kernel/module/version.c @@ -79,17 +79,17 @@ int check_modstruct_version(const struct load_info *info, .name = "module_layout", .gplok = true, }; + bool have_symbol; /* * Since this should be found in kernel (which can't be removed), no - * locking is necessary -- use preempt_disable() to placate lockdep. + * locking is necessary. Regardless use a RCU read section to keep + * lockdep happy. */ - preempt_disable(); - if (!find_symbol(&fsa)) { - preempt_enable(); - BUG(); - } - preempt_enable(); + scoped_guard(rcu) + have_symbol = find_symbol(&fsa); + BUG_ON(!have_symbol); + return check_version(info, "module_layout", mod, fsa.crc); } |