diff options
Diffstat (limited to 'kernel/module')
| -rw-r--r-- | kernel/module/internal.h | 7 | ||||
| -rw-r--r-- | kernel/module/main.c | 121 | ||||
| -rw-r--r-- | kernel/module/strict_rwx.c | 47 |
3 files changed, 147 insertions, 28 deletions
diff --git a/kernel/module/internal.h b/kernel/module/internal.h index 626cf8668a7e..8d74b0a21c82 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -322,8 +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/main.c b/kernel/module/main.c index 5c6ab20240a6..413ac6ea3702 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -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. */ @@ -1083,6 +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) @@ -1092,6 +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; @@ -1562,12 +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 }, @@ -1659,15 +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) @@ -2768,7 +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. */ @@ -2786,22 +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 @@ -3336,7 +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); @@ -3399,11 +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); diff --git a/kernel/module/strict_rwx.c b/kernel/module/strict_rwx.c index 03f4142cfbf4..8fd438529fbc 100644 --- a/kernel/module/strict_rwx.c +++ b/kernel/module/strict_rwx.c @@ -87,8 +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; @@ -106,3 +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; + } + } + } +} |