diff options
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 227 |
1 files changed, 157 insertions, 70 deletions
diff --git a/kernel/module.c b/kernel/module.c index 794ebe8e878d..5f71aa63ed2a 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -53,6 +53,7 @@ #include <asm/sections.h> #include <linux/tracepoint.h> #include <linux/ftrace.h> +#include <linux/livepatch.h> #include <linux/async.h> #include <linux/percpu.h> #include <linux/kmemleak.h> @@ -984,6 +985,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, mod->exit(); blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_GOING, mod); + klp_module_going(mod); ftrace_release_mod(mod); async_synchronize_full(); @@ -1971,6 +1973,83 @@ static void module_enable_nx(const struct module *mod) { } static void module_disable_nx(const struct module *mod) { } #endif +#ifdef CONFIG_LIVEPATCH +/* + * Persist Elf information about a module. Copy the Elf header, + * section header table, section string table, and symtab section + * index from info to mod->klp_info. + */ +static int copy_module_elf(struct module *mod, struct load_info *info) +{ + unsigned int size, symndx; + int ret; + + size = sizeof(*mod->klp_info); + mod->klp_info = kmalloc(size, GFP_KERNEL); + if (mod->klp_info == NULL) + return -ENOMEM; + + /* Elf header */ + size = sizeof(mod->klp_info->hdr); + memcpy(&mod->klp_info->hdr, info->hdr, size); + + /* Elf section header table */ + size = sizeof(*info->sechdrs) * info->hdr->e_shnum; + mod->klp_info->sechdrs = kmalloc(size, GFP_KERNEL); + if (mod->klp_info->sechdrs == NULL) { + ret = -ENOMEM; + goto free_info; + } + memcpy(mod->klp_info->sechdrs, info->sechdrs, size); + + /* Elf section name string table */ + size = info->sechdrs[info->hdr->e_shstrndx].sh_size; + mod->klp_info->secstrings = kmalloc(size, GFP_KERNEL); + if (mod->klp_info->secstrings == NULL) { + ret = -ENOMEM; + goto free_sechdrs; + } + memcpy(mod->klp_info->secstrings, info->secstrings, size); + + /* Elf symbol section index */ + symndx = info->index.sym; + mod->klp_info->symndx = symndx; + + /* + * For livepatch modules, core_kallsyms.symtab is a complete + * copy of the original symbol table. Adjust sh_addr to point + * to core_kallsyms.symtab since the copy of the symtab in module + * init memory is freed at the end of do_init_module(). + */ + mod->klp_info->sechdrs[symndx].sh_addr = \ + (unsigned long) mod->core_kallsyms.symtab; + + return 0; + +free_sechdrs: + kfree(mod->klp_info->sechdrs); +free_info: + kfree(mod->klp_info); + return ret; +} + +static void free_module_elf(struct module *mod) +{ + kfree(mod->klp_info->sechdrs); + kfree(mod->klp_info->secstrings); + kfree(mod->klp_info); +} +#else /* !CONFIG_LIVEPATCH */ +static int copy_module_elf(struct module *mod, struct load_info *info) +{ + return 0; +} + +static void free_module_elf(struct module *mod) +{ +} +#endif /* CONFIG_LIVEPATCH */ + void __weak module_memfree(void *module_region) { vfree(module_region); @@ -2009,6 +2088,9 @@ static void free_module(struct module *mod) /* Free any allocated parameters. */ destroy_params(mod->kp, mod->num_kp); + if (is_livepatch_module(mod)) + free_module_elf(mod); + /* Now we can delete it from the lists */ mutex_lock(&module_mutex); /* Unlink carefully: kallsyms could be walking list. */ @@ -2124,6 +2206,10 @@ static int simplify_symbols(struct module *mod, const struct load_info *info) (long)sym[i].st_value); break; + case SHN_LIVEPATCH: + /* Livepatch symbols are resolved by livepatch */ + break; + case SHN_UNDEF: ksym = resolve_symbol_wait(mod, info, name); /* Ok if resolved. */ @@ -2172,6 +2258,10 @@ 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 = apply_relocate(info->sechdrs, info->strtab, info->index.sym, i, mod); @@ -2467,7 +2557,7 @@ static void layout_symtab(struct module *mod, struct load_info *info) /* Compute total space required for the core symbols' strtab. */ for (ndst = i = 0; i < nsrc; i++) { - if (i == 0 || + if (i == 0 || is_livepatch_module(mod) || is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum, info->index.pcpu)) { strtab_size += strlen(&info->strtab[src[i].st_name])+1; @@ -2526,7 +2616,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info) mod->core_kallsyms.strtab = s = mod->core_layout.base + info->stroffs; src = mod->kallsyms->symtab; for (ndst = i = 0; i < mod->kallsyms->num_symtab; i++) { - if (i == 0 || + if (i == 0 || is_livepatch_module(mod) || is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum, info->index.pcpu)) { dst[ndst] = src[i]; @@ -2665,6 +2755,26 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l return 0; } +#ifdef CONFIG_LIVEPATCH +static int find_livepatch_modinfo(struct module *mod, struct load_info *info) +{ + mod->klp = get_modinfo(info, "livepatch") ? true : false; + + return 0; +} +#else /* !CONFIG_LIVEPATCH */ +static int find_livepatch_modinfo(struct module *mod, struct load_info *info) +{ + if (get_modinfo(info, "livepatch")) { + pr_err("%s: module is marked as livepatch module, but livepatch support is disabled", + mod->name); + return -ENOEXEC; + } + + return 0; +} +#endif /* CONFIG_LIVEPATCH */ + /* Sets info->hdr and info->len. */ static int copy_module_from_user(const void __user *umod, unsigned long len, struct load_info *info) @@ -2675,7 +2785,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len, if (info->len < sizeof(*(info->hdr))) return -ENOEXEC; - err = security_kernel_module_from_file(NULL); + err = security_kernel_read_file(NULL, READING_MODULE); if (err) return err; @@ -2693,63 +2803,6 @@ static int copy_module_from_user(const void __user *umod, unsigned long len, return 0; } -/* Sets info->hdr and info->len. */ -static int copy_module_from_fd(int fd, struct load_info *info) -{ - struct fd f = fdget(fd); - int err; - struct kstat stat; - loff_t pos; - ssize_t bytes = 0; - - if (!f.file) - return -ENOEXEC; - - err = security_kernel_module_from_file(f.file); - if (err) - goto out; - - err = vfs_getattr(&f.file->f_path, &stat); - if (err) - goto out; - - if (stat.size > INT_MAX) { - err = -EFBIG; - goto out; - } - - /* Don't hand 0 to vmalloc, it whines. */ - if (stat.size == 0) { - err = -EINVAL; - goto out; - } - - info->hdr = vmalloc(stat.size); - if (!info->hdr) { - err = -ENOMEM; - goto out; - } - - pos = 0; - while (pos < stat.size) { - bytes = kernel_read(f.file, pos, (char *)(info->hdr) + pos, - stat.size - pos); - if (bytes < 0) { - vfree(info->hdr); - err = bytes; - goto out; - } - if (bytes == 0) - break; - pos += bytes; - } - info->len = pos; - -out: - fdput(f); - return err; -} - static void free_copy(struct load_info *info) { vfree(info->hdr); @@ -2876,6 +2929,10 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags) "is unknown, you have been warned.\n", mod->name); } + err = find_livepatch_modinfo(mod, info); + if (err) + return err; + /* Set up license info based on the info section */ set_license(mod, get_modinfo(info, "license")); @@ -3315,6 +3372,7 @@ fail: module_put(mod); blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_GOING, mod); + klp_module_going(mod); ftrace_release_mod(mod); free_module(mod); wake_up_all(&module_wq); @@ -3392,9 +3450,6 @@ static int complete_formation(struct module *mod, struct load_info *info) mod->state = MODULE_STATE_COMING; mutex_unlock(&module_mutex); - ftrace_module_enable(mod); - blocking_notifier_call_chain(&module_notify_list, - MODULE_STATE_COMING, mod); return 0; out: @@ -3402,6 +3457,20 @@ out: return err; } +static int prepare_coming_module(struct module *mod) +{ + int err; + + ftrace_module_enable(mod); + err = klp_module_coming(mod); + if (err) + return err; + + blocking_notifier_call_chain(&module_notify_list, + MODULE_STATE_COMING, mod); + return 0; +} + static int unknown_module_param_cb(char *param, char *val, const char *modname, void *arg) { @@ -3516,13 +3585,17 @@ static int load_module(struct load_info *info, const char __user *uargs, if (err) goto ddebug_cleanup; + err = prepare_coming_module(mod); + if (err) + goto bug_cleanup; + /* Module is ready to execute: parsing args may do that. */ after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp, -32768, 32767, mod, unknown_module_param_cb); if (IS_ERR(after_dashes)) { err = PTR_ERR(after_dashes); - goto bug_cleanup; + goto coming_cleanup; } else if (after_dashes) { pr_warn("%s: parameters '%s' after `--' ignored\n", mod->name, after_dashes); @@ -3531,7 +3604,13 @@ static int load_module(struct load_info *info, const char __user *uargs, /* Link in to syfs. */ err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp); if (err < 0) - goto bug_cleanup; + goto coming_cleanup; + + if (is_livepatch_module(mod)) { + err = copy_module_elf(mod, info); + if (err < 0) + goto sysfs_cleanup; + } /* Get rid of temporary copy. */ free_copy(info); @@ -3541,15 +3620,18 @@ static int load_module(struct load_info *info, const char __user *uargs, return do_init_module(mod); + sysfs_cleanup: + mod_sysfs_teardown(mod); + coming_cleanup: + blocking_notifier_call_chain(&module_notify_list, + MODULE_STATE_GOING, mod); + klp_module_going(mod); bug_cleanup: /* module_bug_cleanup needs module_mutex protection */ mutex_lock(&module_mutex); module_bug_cleanup(mod); mutex_unlock(&module_mutex); - blocking_notifier_call_chain(&module_notify_list, - MODULE_STATE_GOING, mod); - /* we can't deallocate the module until we clear memory protection */ module_disable_ro(mod); module_disable_nx(mod); @@ -3611,8 +3693,10 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) { - int err; struct load_info info = { }; + loff_t size; + void *hdr; + int err; err = may_init_module(); if (err) @@ -3624,9 +3708,12 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) |MODULE_INIT_IGNORE_VERMAGIC)) return -EINVAL; - err = copy_module_from_fd(fd, &info); + err = kernel_read_file_from_fd(fd, &hdr, &size, INT_MAX, + READING_MODULE); if (err) return err; + info.hdr = hdr; + info.len = size; return load_module(&info, uargs, flags); } |