// SPDX-License-Identifier: GPL-2.0-or-later /* Helpers for initial module or kernel cmdline parsing Copyright (C) 2001 Rusty Russell. */ #include <linux/kernel.h> #include <linux/string.h> #include <linux/errno.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/device.h> #include <linux/err.h> #include <linux/slab.h> #include <linux/ctype.h> #include <linux/security.h> #ifdef CONFIG_SYSFS /* Protects all built-in parameters, modules use their own param_lock */ static DEFINE_MUTEX(param_lock); /* Use the module's mutex, or if built-in use the built-in mutex */ #ifdef CONFIG_MODULES #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : ¶m_lock) #else #define KPARAM_MUTEX(mod) (¶m_lock) #endif static inline void check_kparam_locked(struct module *mod) { BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod))); } #else static inline void check_kparam_locked(struct module *mod) { } #endif /* !CONFIG_SYSFS */ /* This just allows us to keep track of which parameters are kmalloced. */ struct kmalloced_param { struct list_head list; char val[]; }; static LIST_HEAD(kmalloced_params); static DEFINE_SPINLOCK(kmalloced_params_lock); static void *kmalloc_parameter(unsigned int size) { struct kmalloced_param *p; p = kmalloc(sizeof(*p) + size, GFP_KERNEL); if (!p) return NULL; spin_lock(&kmalloced_params_lock); list_add(&p->list, &kmalloced_params); spin_unlock(&kmalloced_params_lock); return p->val; } /* Does nothing if parameter wasn't kmalloced above. */ static void maybe_kfree_parameter(void *param) { struct kmalloced_param *p; spin_lock(&kmalloced_params_lock); list_for_each_entry(p, &kmalloced_params, list) { if (p->val == param) { list_del(&p->list); kfree(p); break; } } spin_unlock(&kmalloced_params_lock); } static char dash2underscore(char c) { if (c == '-') return '_'; return c; } bool parameqn(const char *a, const char *b, size_t n) { size_t i; for (i = 0; i < n; i++) { if (dash2underscore(a[i]) != dash2underscore(b[i])) return false; } return true; } bool parameq(const char *a, const char *b) { return parameqn(a, b, strlen(a)+1); } static bool param_check_unsafe(const struct kernel_param *kp) { if (kp->flags & KERNEL_PARAM_FL_HWPARAM && security_locked_down(LOCKDOWN_MODULE_PARAMETERS)) return false; if (kp->flags & KERNEL_PARAM_FL_UNSAFE) { pr_notice("Setting dangerous option %s - tainting kernel\n", kp->name); add_taint(TAINT_USER, LOCKDEP_STILL_OK); } return true; } static int parse_one(char *param, char *val, const char *doing, const struct kernel_param *params, unsigned num_params, s16 min_level, s16 max_level, void *arg, int (*handle_unknown)(char *param, char *val, const char *doing, void *arg)) { unsigned int i; int err; /* Find parameter */ for (i = 0; i < num_params; i++) { if (parameq(param, params[i].name)) { if (params[i].level < min_level || params[i].level > max_level) return 0; /* No one handled NULL, so do it here. */ if (!val && !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG)) return -EINVAL; pr_debug("handling %s with %p\n", param, params[i].ops->set); kernel_param_lock(params[i].mod); if (param_check_unsafe(¶ms[i])) err = params[i].ops->set(val, ¶ms[i]); else err = -EPERM; kernel_param_unlock(params[i].mod); return err; } } if (handle_unknown) { pr_debug("doing %s: %s='%s'\n", doing, param, val); return handle_unknown(param, val, doing, arg); } pr_debug("Unknown argument '%s'\n", param); return -ENOENT; } /* Args looks like "foo=bar,bar2 baz=fuz wiz". */ char *parse_args(const char *doing, char *args, const struct kernel_param *params, unsigned num, s16 min_level, s16 max_level, void *arg, int (*unknown)(char *param, char *val, const char *doing, void *arg)) { char *param, *val, *err = NULL; /* Chew leading spaces */ args = skip_spaces(args); if (*args) pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args); while (*args) { int ret; int irq_was_disabled; args = next_arg(args, ¶m, &val); /* Stop at -- */ if (!val && strcmp(param, "--") == 0) return err ?: args; irq_was_disabled = irqs_disabled(); ret = parse_one(param, val, doing, params, num, min_level, max_level, arg, unknown); if (irq_was_disabled && !irqs_disabled()) pr_warn("%s: option '%s' enabled irq's!\n", doing, param); switch (ret) { case 0: continue; case -ENOENT: pr_err("%s: Unknown parameter `%s'\n", doing, param); break; case -ENOSPC: pr_err("%s: `%s' too large for parameter `%s'\n", doing, val ?: "", param); break; default: pr_err("%s: `%s' invalid for parameter `%s'\n", doing, val ?: "", param); break; } err = ERR_PTR(ret); } return err; } /* Lazy bastard, eh? */ #define STANDARD_PARAM_DEF(name, type, format, strtolfn) \ int param_set_##name(const char *val, const struct kernel_param *kp) \ { \ return strtolfn(val, 0, (type *)kp->arg); \ } \ int param_get_##name(char *buffer, const struct kernel_param *kp) \ { \ return scnprintf(buffer, PAGE_SIZE, format "\n", \ *((type *)kp->arg)); \ } \ const struct kernel_param_ops param_ops_##name = { \ .set = param_set_##name, \ .get = param_get_##name, \ }; \ EXPORT_SYMBOL(param_set_##name); \ EXPORT_SYMBOL(param_get_##name); \ EXPORT_SYMBOL(param_ops_##name) STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8); STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16); STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16); STANDARD_PARAM_DEF(int, int, "%i", kstrtoint); STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint); STANDARD_PARAM_DEF(long, long, "%li", kstrtol); STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul); STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull); STANDARD_PARAM_DEF(hexint, unsigned int, "%#08x", kstrtouint); int param_set_charp(const char *val, const struct kernel_param *kp) { if (strlen(val) > 1024) { pr_err("%s: string parameter too long\n", kp->name); return -ENOSPC; } maybe_kfree_parameter(*(char **)kp->arg); /* This is a hack. We can't kmalloc in early boot, and we * don't need to; this mangled commandline is preserved. */ if (slab_is_available()) { *(char **)kp->arg = kmalloc_parameter(strlen(val)+1); if (!*(char **)kp->arg) return -ENOMEM; strcpy(*(char **)kp->arg, val); } else *(const char **)kp->arg = val; return 0; } EXPORT_SYMBOL(param_set_charp); int param_get_charp(char *buffer, const struct kernel_param *kp) { return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg)); } EXPORT_SYMBOL(param_get_charp); void param_free_charp(void *arg) { maybe_kfree_parameter(*((char **)arg)); } EXPORT_SYMBOL(param_free_charp); const struct kernel_param_ops param_ops_charp = { .set = param_set_charp, .get = param_get_charp, .free = param_free_charp, }; EXPORT_SYMBOL(param_ops_charp); /* Actually could be a bool or an int, for historical reasons. */ int param_set_bool(const char *val, const struct kernel_param *kp) { /* No equals means "set"... */ if (!val) val = "1"; /* One of =[yYnN01] */ return strtobool(val, kp->arg); } EXPORT_SYMBOL(param_set_bool); int param_get_bool(char *buffer, const struct kernel_param *kp) { /* Y and N chosen as being relatively non-coder friendly */ return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N'); } EXPORT_SYMBOL(param_get_bool); const struct kernel_param_ops param_ops_bool = { .flags = KERNEL_PARAM_OPS_FL_NOARG, .set = param_set_bool, .get = param_get_bool, }; EXPORT_SYMBOL(param_ops_bool); int param_set_bool_enable_only(const char *val, const struct kernel_param *kp) { int err = 0; bool new_value; bool orig_value = *(bool *)kp->arg; struct kernel_param dummy_kp = *kp; dummy_kp.arg = &new_value; err = param_set_bool(val, &dummy_kp); if (err) return err; /* Don't let them unset it once it's set! */ if (!new_value && orig_value) return -EROFS; if (new_value) err = param_set_bool(val, kp); return err; } EXPORT_SYMBOL_GPL(param_set_bool_enable_only); const struct kernel_param_ops param_ops_bool_enable_only = { .flags = KERNEL_PARAM_OPS_FL_NOARG, .set = param_set_bool_enable_only, .get = param_get_bool, }; EXPORT_SYMBOL_GPL(param_ops_bool_enable_only); /* This one must be bool. */ int param_set_invbool(const char *val, const struct kernel_param *kp) { int ret; bool boolval; struct kernel_param dummy; dummy.arg = &boolval; ret = param_set_bool(val, &dummy); if (ret == 0) *(bool *)kp->arg = !boolval; return ret; } EXPORT_SYMBOL(param_set_invbool); int param_get_invbool(char *buffer, const struct kernel_param *kp) { return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y'); } EXPORT_SYMBOL(param_get_invbool); const struct kernel_param_ops param_ops_invbool = { .set = param_set_invbool, .get = param_get_invbool, }; EXPORT_SYMBOL(param_ops_invbool); int param_set_bint(const char *val, const struct kernel_param *kp) { /* Match bool exactly, by re-using it. */ struct kernel_param boolkp = *kp; bool v; int ret; boolkp.arg = &v; ret = param_set_bool(val, &boolkp); if (ret == 0) *(int *)kp->arg = v; return ret; } EXPORT_SYMBOL(param_set_bint); const struct kernel_param_ops param_ops_bint = { .flags = KERNEL_PARAM_OPS_FL_NOARG, .set = param_set_bint, .get = param_get_int, }; EXPORT_SYMBOL(param_ops_bint); /* We break the rule and mangle the string. */ static int param_array(struct module *mod, const char *name, const char *val, unsigned int min, unsigned int max, void *elem, int elemsize, int (*set)(const char *, const struct kernel_param *kp), s16 level, unsigned int *num) { int ret; struct kernel_param kp; char save; /* Get the name right for errors. */ kp.name = name; kp.arg = elem; kp.level = level; *num = 0; /* We expect a comma-separated list of values. */ do { int len; if (*num == max) { pr_err("%s: can only take %i arguments\n", name, max); return -EINVAL; } len = strcspn(val, ","); /* nul-terminate and parse */ save = val[len]; ((char *)val)[len] = '\0'; check_kparam_locked(mod); ret = set(val, &kp); if (ret != 0) return ret; kp.arg += elemsize; val += len+1; (*num)++; } while (save == ','); if (*num < min) { pr_err("%s: needs at least %i arguments\n", name, min); return -EINVAL; } return 0; } static int param_array_set(const char *val, const struct kernel_param *kp) { const struct kparam_array *arr = kp->arr; unsigned int temp_num; return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem, arr->elemsize, arr->ops->set, kp->level, arr->num ?: &temp_num); } static int param_array_get(char *buffer, const struct kernel_param *kp) { int i, off, ret; const struct kparam_array *arr = kp->arr; struct kernel_param p = *kp; for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) { /* Replace \n with comma */ if (i) buffer[off - 1] = ','; p.arg = arr->elem + arr->elemsize * i; check_kparam_locked(p.mod); ret = arr->ops->get(buffer + off, &p); if (ret < 0) return ret; off += ret; } buffer[off] = '\0'; return off; } static void param_array_free(void *arg) { unsigned int i; const struct kparam_array *arr = arg; if (arr->ops->free) for (i = 0; i < (arr->num ? *arr->num : arr->max); i++) arr->ops->free(arr->elem + arr->elemsize * i); } const struct kernel_param_ops param_array_ops = { .set = param_array_set, .get = param_array_get, .free = param_array_free, }; EXPORT_SYMBOL(param_array_ops); int param_set_copystring(const char *val, const struct kernel_param *kp) { const struct kparam_string *kps = kp->str; if (strlen(val)+1 > kps->maxlen) { pr_err("%s: string doesn't fit in %u chars.\n", kp->name, kps->maxlen-1); return -ENOSPC; } strcpy(kps->string, val); return 0; } EXPORT_SYMBOL(param_set_copystring); int param_get_string(char *buffer, const struct kernel_param *kp) { const struct kparam_string *kps = kp->str; return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string); } EXPORT_SYMBOL(param_get_string); const struct kernel_param_ops param_ops_string = { .set = param_set_copystring, .get = param_get_string, }; EXPORT_SYMBOL(param_ops_string); /* sysfs output in /sys/modules/XYZ/parameters/ */ #define to_module_attr(n) container_of(n, struct module_attribute, attr) #define to_module_kobject(n) container_of(n, struct module_kobject, kobj) struct param_attribute { struct module_attribute mattr; const struct kernel_param *param; }; struct module_param_attrs { unsigned int num; struct attribute_group grp; struct param_attribute attrs[]; }; #ifdef CONFIG_SYSFS #define to_param_attr(n) container_of(n, struct param_attribute, mattr) static ssize_t param_attr_show(struct module_attribute *mattr, struct module_kobject *mk, char *buf) { int count; struct param_attribute *attribute = to_param_attr(mattr); if (!attribute->param->ops->get) return -EPERM; kernel_param_lock(mk->mod); count = attribute->param->ops->get(buf, attribute->param); kernel_param_unlock(mk->mod); return count; } /* sysfs always hands a nul-terminated string in buf. We rely on that. */ static ssize_t param_attr_store(struct module_attribute *mattr, struct module_kobject *mk, const char *buf, size_t len) { int err; struct param_attribute *attribute = to_param_attr(mattr); if (!attribute->param->ops->set) return -EPERM; kernel_param_lock(mk->mod); if (param_check_unsafe(attribute->param)) err = attribute->param->ops->set(buf, attribute->param); else err = -EPERM; kernel_param_unlock(mk->mod); if (!err) return len; return err; } #endif #ifdef CONFIG_MODULES #define __modinit #else #define __modinit __init #endif #ifdef CONFIG_SYSFS void kernel_param_lock(struct module *mod) { mutex_lock(KPARAM_MUTEX(mod)); } void kernel_param_unlock(struct module *mod) { mutex_unlock(KPARAM_MUTEX(mod)); } EXPORT_SYMBOL(kernel_param_lock); EXPORT_SYMBOL(kernel_param_unlock); /* * add_sysfs_param - add a parameter to sysfs * @mk: struct module_kobject * @kp: the actual parameter definition to add to sysfs * @name: name of parameter * * Create a kobject if for a (per-module) parameter if mp NULL, and * create file in sysfs. Returns an error on out of memory. Always cleans up * if there's an error. */ static __modinit int add_sysfs_param(struct module_kobject *mk, const struct kernel_param *kp, const char *name) { struct module_param_attrs *new_mp; struct attribute **new_attrs; unsigned int i; /* We don't bother calling this with invisible parameters. */ BUG_ON(!kp->perm); if (!mk->mp) { /* First allocation. */ mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL); if (!mk->mp) return -ENOMEM; mk->mp->grp.name = "parameters"; /* NULL-terminated attribute array. */ mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]), GFP_KERNEL); /* Caller will cleanup via free_module_param_attrs */ if (!mk->mp->grp.attrs) return -ENOMEM; } /* Enlarge allocations. */ new_mp = krealloc(mk->mp, sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1), GFP_KERNEL); if (!new_mp) return -ENOMEM; mk->mp = new_mp; /* Extra pointer for NULL terminator */ new_attrs = krealloc(mk->mp->grp.attrs, sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2), GFP_KERNEL); if (!new_attrs) return -ENOMEM; mk->mp->grp.attrs = new_attrs; /* Tack new one on the end. */ memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0])); sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr); mk->mp->attrs[mk->mp->num].param = kp; mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show; /* Do not allow runtime DAC changes to make param writable. */ if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0) mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store; else mk->mp->attrs[mk->mp->num].mattr.store = NULL; mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name; mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm; mk->mp->num++; /* Fix up all the pointers, since krealloc can move us */ for (i = 0; i < mk->mp->num; i++) mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr; mk->mp->grp.attrs[mk->mp->num] = NULL; return 0; } #ifdef CONFIG_MODULES static void free_module_param_attrs(struct module_kobject *mk) { if (mk->mp) kfree(mk->mp->grp.attrs); kfree(mk->mp); mk->mp = NULL; } /* * module_param_sysfs_setup - setup sysfs support for one module * @mod: module * @kparam: module parameters (array) * @num_params: number of module parameters * * Adds sysfs entries for module parameters under * /sys/module/[mod->name]/parameters/ */ int module_param_sysfs_setup(struct module *mod, const struct kernel_param *kparam, unsigned int num_params) { int i, err; bool params = false; for (i = 0; i < num_params; i++) { if (kparam[i].perm == 0) continue; err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name); if (err) { free_module_param_attrs(&mod->mkobj); return err; } params = true; } if (!params) return 0; /* Create the param group. */ err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp); if (err) free_module_param_attrs(&mod->mkobj); return err; } /* * module_param_sysfs_remove - remove sysfs support for one module * @mod: module * * Remove sysfs entries for module parameters and the corresponding * kobject. */ void module_param_sysfs_remove(struct module *mod) { if (mod->mkobj.mp) { sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp); /* We are positive that no one is using any param * attrs at this point. Deallocate immediately. */ free_module_param_attrs(&mod->mkobj); } } #endif void destroy_params(const struct kernel_param *params, unsigned num) { unsigned int i; for (i = 0; i < num; i++) if (params[i].ops->free) params[i].ops->free(params[i].arg); } static struct module_kobject * __init locate_module_kobject(const char *name) { struct module_kobject *mk; struct kobject *kobj; int err; kobj = kset_find_obj(module_kset, name); if (kobj) { mk = to_module_kobject(kobj); } else { mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL); BUG_ON(!mk); mk->mod = THIS_MODULE; mk->kobj.kset = module_kset; err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL, "%s", name); #ifdef CONFIG_MODULES if (!err) err = sysfs_create_file(&mk->kobj, &module_uevent.attr); #endif if (err) { kobject_put(&mk->kobj); pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n", name, err); return NULL; } /* So that we hold reference in both cases. */ kobject_get(&mk->kobj); } return mk; } static void __init kernel_add_sysfs_param(const char *name, const struct kernel_param *kparam, unsigned int name_skip) { struct module_kobject *mk; int err; mk = locate_module_kobject(name); if (!mk) return; /* We need to remove old parameters before adding more. */ if (mk->mp) sysfs_remove_group(&mk->kobj, &mk->mp->grp); /* These should not fail at boot. */ err = add_sysfs_param(mk, kparam, kparam->name + name_skip); BUG_ON(err); err = sysfs_create_group(&mk->kobj, &mk->mp->grp); BUG_ON(err); kobject_uevent(&mk->kobj, KOBJ_ADD); kobject_put(&mk->kobj); } /* * param_sysfs_builtin - add sysfs parameters for built-in modules * * Add module_parameters to sysfs for "modules" built into the kernel. * * The "module" name (KBUILD_MODNAME) is stored before a dot, the * "parameter" name is stored behind a dot in kernel_param->name. So, * extract the "module" name for all built-in kernel_param-eters, * and for all who have the same, call kernel_add_sysfs_param. */ static void __init param_sysfs_builtin(void) { const struct kernel_param *kp; unsigned int name_len; char modname[MODULE_NAME_LEN]; for (kp = __start___param; kp < __stop___param; kp++) { char *dot; if (kp->perm == 0) continue; dot = strchr(kp->name, '.'); if (!dot) { /* This happens for core_param() */ strcpy(modname, "kernel"); name_len = 0; } else { name_len = dot - kp->name + 1; strlcpy(modname, kp->name, name_len); } kernel_add_sysfs_param(modname, kp, name_len); } } ssize_t __modver_version_show(struct module_attribute *mattr, struct module_kobject *mk, char *buf) { struct module_version_attribute *vattr = container_of(mattr, struct module_version_attribute, mattr); return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version); } extern const struct module_version_attribute *__start___modver[]; extern const struct module_version_attribute *__stop___modver[]; static void __init version_sysfs_builtin(void) { const struct module_version_attribute **p; struct module_kobject *mk; int err; for (p = __start___modver; p < __stop___modver; p++) { const struct module_version_attribute *vattr = *p; mk = locate_module_kobject(vattr->module_name); if (mk) { err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr); WARN_ON_ONCE(err); kobject_uevent(&mk->kobj, KOBJ_ADD); kobject_put(&mk->kobj); } } } /* module-related sysfs stuff */ static ssize_t module_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct module_attribute *attribute; struct module_kobject *mk; int ret; attribute = to_module_attr(attr); mk = to_module_kobject(kobj); if (!attribute->show) return -EIO; ret = attribute->show(attribute, mk, buf); return ret; } static ssize_t module_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t len) { struct module_attribute *attribute; struct module_kobject *mk; int ret; attribute = to_module_attr(attr); mk = to_module_kobject(kobj); if (!attribute->store) return -EIO; ret = attribute->store(attribute, mk, buf, len); return ret; } static const struct sysfs_ops module_sysfs_ops = { .show = module_attr_show, .store = module_attr_store, }; static int uevent_filter(struct kset *kset, struct kobject *kobj) { struct kobj_type *ktype = get_ktype(kobj); if (ktype == &module_ktype) return 1; return 0; } static const struct kset_uevent_ops module_uevent_ops = { .filter = uevent_filter, }; struct kset *module_kset; int module_sysfs_initialized; static void module_kobj_release(struct kobject *kobj) { struct module_kobject *mk = to_module_kobject(kobj); complete(mk->kobj_completion); } struct kobj_type module_ktype = { .release = module_kobj_release, .sysfs_ops = &module_sysfs_ops, }; /* * param_sysfs_init - wrapper for built-in params support */ static int __init param_sysfs_init(void) { module_kset = kset_create_and_add("module", &module_uevent_ops, NULL); if (!module_kset) { printk(KERN_WARNING "%s (%d): error creating kset\n", __FILE__, __LINE__); return -ENOMEM; } module_sysfs_initialized = 1; version_sysfs_builtin(); param_sysfs_builtin(); return 0; } subsys_initcall(param_sysfs_init); #endif /* CONFIG_SYSFS */