diff options
Diffstat (limited to 'drivers/firmware/efi/efivars.c')
| -rw-r--r-- | drivers/firmware/efi/efivars.c | 670 |
1 files changed, 670 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c new file mode 100644 index 000000000..e6b16b3a1 --- /dev/null +++ b/drivers/firmware/efi/efivars.c @@ -0,0 +1,670 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Originally from efivars.c, + * + * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com> + * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com> + * + * This code takes all variables accessible from EFI runtime and + * exports them via sysfs + */ + +#include <linux/efi.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/ucs2_string.h> +#include <linux/compat.h> + +#define EFIVARS_VERSION "0.08" +#define EFIVARS_DATE "2004-May-17" + +MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>"); +MODULE_DESCRIPTION("sysfs interface to EFI Variables"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(EFIVARS_VERSION); + +static LIST_HEAD(efivar_sysfs_list); + +static struct kset *efivars_kset; + +static struct bin_attribute *efivars_new_var; +static struct bin_attribute *efivars_del_var; + +struct compat_efi_variable { + efi_char16_t VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)]; + efi_guid_t VendorGuid; + __u32 DataSize; + __u8 Data[1024]; + __u32 Status; + __u32 Attributes; +} __packed; + +struct efivar_attribute { + struct attribute attr; + ssize_t (*show) (struct efivar_entry *entry, char *buf); + ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count); +}; + +#define EFIVAR_ATTR(_name, _mode, _show, _store) \ +struct efivar_attribute efivar_attr_##_name = { \ + .attr = {.name = __stringify(_name), .mode = _mode}, \ + .show = _show, \ + .store = _store, \ +}; + +#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr) +#define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj) + +/* + * Prototype for sysfs creation function + */ +static int +efivar_create_sysfs_entry(struct efivar_entry *new_var); + +static ssize_t +efivar_guid_read(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + char *str = buf; + + if (!entry || !buf) + return 0; + + efi_guid_to_str(&var->VendorGuid, str); + str += strlen(str); + str += sprintf(str, "\n"); + + return str - buf; +} + +static ssize_t +efivar_attr_read(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + unsigned long size = sizeof(var->Data); + char *str = buf; + int ret; + + if (!entry || !buf) + return -EINVAL; + + ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data); + var->DataSize = size; + if (ret) + return -EIO; + + if (var->Attributes & EFI_VARIABLE_NON_VOLATILE) + str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n"); + if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS) + str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n"); + if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS) + str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n"); + if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) + str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n"); + if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) + str += sprintf(str, + "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n"); + if (var->Attributes & + EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) + str += sprintf(str, + "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n"); + if (var->Attributes & EFI_VARIABLE_APPEND_WRITE) + str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n"); + return str - buf; +} + +static ssize_t +efivar_size_read(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + unsigned long size = sizeof(var->Data); + char *str = buf; + int ret; + + if (!entry || !buf) + return -EINVAL; + + ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data); + var->DataSize = size; + if (ret) + return -EIO; + + str += sprintf(str, "0x%lx\n", var->DataSize); + return str - buf; +} + +static ssize_t +efivar_data_read(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + unsigned long size = sizeof(var->Data); + int ret; + + if (!entry || !buf) + return -EINVAL; + + ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data); + var->DataSize = size; + if (ret) + return -EIO; + + memcpy(buf, var->Data, var->DataSize); + return var->DataSize; +} + +static inline int +sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor, + unsigned long size, u32 attributes, u8 *data) +{ + /* + * If only updating the variable data, then the name + * and guid should remain the same + */ + if (memcmp(name, var->VariableName, sizeof(var->VariableName)) || + efi_guidcmp(vendor, var->VendorGuid)) { + printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n"); + return -EINVAL; + } + + if ((size <= 0) || (attributes == 0)){ + printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n"); + return -EINVAL; + } + + if ((attributes & ~EFI_VARIABLE_MASK) != 0 || + efivar_validate(vendor, name, data, size) == false) { + printk(KERN_ERR "efivars: Malformed variable content\n"); + return -EINVAL; + } + + return 0; +} + +static void +copy_out_compat(struct efi_variable *dst, struct compat_efi_variable *src) +{ + memcpy(dst->VariableName, src->VariableName, EFI_VAR_NAME_LEN); + memcpy(dst->Data, src->Data, sizeof(src->Data)); + + dst->VendorGuid = src->VendorGuid; + dst->DataSize = src->DataSize; + dst->Attributes = src->Attributes; +} + +/* + * We allow each variable to be edited via rewriting the + * entire efi variable structure. + */ +static ssize_t +efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count) +{ + struct efi_variable *new_var, *var = &entry->var; + efi_char16_t *name; + unsigned long size; + efi_guid_t vendor; + u32 attributes; + u8 *data; + int err; + + if (!entry || !buf) + return -EINVAL; + + if (in_compat_syscall()) { + struct compat_efi_variable *compat; + + if (count != sizeof(*compat)) + return -EINVAL; + + compat = (struct compat_efi_variable *)buf; + attributes = compat->Attributes; + vendor = compat->VendorGuid; + name = compat->VariableName; + size = compat->DataSize; + data = compat->Data; + + err = sanity_check(var, name, vendor, size, attributes, data); + if (err) + return err; + + copy_out_compat(&entry->var, compat); + } else { + if (count != sizeof(struct efi_variable)) + return -EINVAL; + + new_var = (struct efi_variable *)buf; + + attributes = new_var->Attributes; + vendor = new_var->VendorGuid; + name = new_var->VariableName; + size = new_var->DataSize; + data = new_var->Data; + + err = sanity_check(var, name, vendor, size, attributes, data); + if (err) + return err; + + memcpy(&entry->var, new_var, count); + } + + err = efivar_entry_set(entry, attributes, size, data, NULL); + if (err) { + printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err); + return -EIO; + } + + return count; +} + +static ssize_t +efivar_show_raw(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + struct compat_efi_variable *compat; + unsigned long datasize = sizeof(var->Data); + size_t size; + int ret; + + if (!entry || !buf) + return 0; + + ret = efivar_entry_get(entry, &var->Attributes, &datasize, var->Data); + var->DataSize = datasize; + if (ret) + return -EIO; + + if (in_compat_syscall()) { + compat = (struct compat_efi_variable *)buf; + + size = sizeof(*compat); + memcpy(compat->VariableName, var->VariableName, + EFI_VAR_NAME_LEN); + memcpy(compat->Data, var->Data, sizeof(compat->Data)); + + compat->VendorGuid = var->VendorGuid; + compat->DataSize = var->DataSize; + compat->Attributes = var->Attributes; + } else { + size = sizeof(*var); + memcpy(buf, var, size); + } + + return size; +} + +/* + * Generic read/write functions that call the specific functions of + * the attributes... + */ +static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr, + char *buf) +{ + struct efivar_entry *var = to_efivar_entry(kobj); + struct efivar_attribute *efivar_attr = to_efivar_attr(attr); + ssize_t ret = -EIO; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (efivar_attr->show) { + ret = efivar_attr->show(var, buf); + } + return ret; +} + +static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr, + const char *buf, size_t count) +{ + struct efivar_entry *var = to_efivar_entry(kobj); + struct efivar_attribute *efivar_attr = to_efivar_attr(attr); + ssize_t ret = -EIO; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (efivar_attr->store) + ret = efivar_attr->store(var, buf, count); + + return ret; +} + +static const struct sysfs_ops efivar_attr_ops = { + .show = efivar_attr_show, + .store = efivar_attr_store, +}; + +static void efivar_release(struct kobject *kobj) +{ + struct efivar_entry *var = to_efivar_entry(kobj); + kfree(var); +} + +static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL); +static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL); +static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL); +static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL); +static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw); + +static struct attribute *def_attrs[] = { + &efivar_attr_guid.attr, + &efivar_attr_size.attr, + &efivar_attr_attributes.attr, + &efivar_attr_data.attr, + &efivar_attr_raw_var.attr, + NULL, +}; + +static struct kobj_type efivar_ktype = { + .release = efivar_release, + .sysfs_ops = &efivar_attr_ops, + .default_attrs = def_attrs, +}; + +static ssize_t efivar_create(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + struct compat_efi_variable *compat = (struct compat_efi_variable *)buf; + struct efi_variable *new_var = (struct efi_variable *)buf; + struct efivar_entry *new_entry; + bool need_compat = in_compat_syscall(); + efi_char16_t *name; + unsigned long size; + u32 attributes; + u8 *data; + int err; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (need_compat) { + if (count != sizeof(*compat)) + return -EINVAL; + + attributes = compat->Attributes; + name = compat->VariableName; + size = compat->DataSize; + data = compat->Data; + } else { + if (count != sizeof(*new_var)) + return -EINVAL; + + attributes = new_var->Attributes; + name = new_var->VariableName; + size = new_var->DataSize; + data = new_var->Data; + } + + if ((attributes & ~EFI_VARIABLE_MASK) != 0 || + efivar_validate(new_var->VendorGuid, name, data, + size) == false) { + printk(KERN_ERR "efivars: Malformed variable content\n"); + return -EINVAL; + } + + new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL); + if (!new_entry) + return -ENOMEM; + + if (need_compat) + copy_out_compat(&new_entry->var, compat); + else + memcpy(&new_entry->var, new_var, sizeof(*new_var)); + + err = efivar_entry_set(new_entry, attributes, size, + data, &efivar_sysfs_list); + if (err) { + if (err == -EEXIST) + err = -EINVAL; + goto out; + } + + if (efivar_create_sysfs_entry(new_entry)) { + printk(KERN_WARNING "efivars: failed to create sysfs entry.\n"); + kfree(new_entry); + } + return count; + +out: + kfree(new_entry); + return err; +} + +static ssize_t efivar_delete(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + struct efi_variable *del_var = (struct efi_variable *)buf; + struct compat_efi_variable *compat; + struct efivar_entry *entry; + efi_char16_t *name; + efi_guid_t vendor; + int err = 0; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (in_compat_syscall()) { + if (count != sizeof(*compat)) + return -EINVAL; + + compat = (struct compat_efi_variable *)buf; + name = compat->VariableName; + vendor = compat->VendorGuid; + } else { + if (count != sizeof(*del_var)) + return -EINVAL; + + name = del_var->VariableName; + vendor = del_var->VendorGuid; + } + + if (efivar_entry_iter_begin()) + return -EINTR; + entry = efivar_entry_find(name, vendor, &efivar_sysfs_list, true); + if (!entry) + err = -EINVAL; + else if (__efivar_entry_delete(entry)) + err = -EIO; + + if (err) { + efivar_entry_iter_end(); + return err; + } + + if (!entry->scanning) { + efivar_entry_iter_end(); + efivar_unregister(entry); + } else + efivar_entry_iter_end(); + + /* It's dead Jim.... */ + return count; +} + +/** + * efivar_create_sysfs_entry - create a new entry in sysfs + * @new_var: efivar entry to create + * + * Returns 0 on success, negative error code on failure + */ +static int +efivar_create_sysfs_entry(struct efivar_entry *new_var) +{ + int short_name_size; + char *short_name; + unsigned long utf8_name_size; + efi_char16_t *variable_name = new_var->var.VariableName; + int ret; + + /* + * Length of the variable bytes in UTF8, plus the '-' separator, + * plus the GUID, plus trailing NUL + */ + utf8_name_size = ucs2_utf8size(variable_name); + short_name_size = utf8_name_size + 1 + EFI_VARIABLE_GUID_LEN + 1; + + short_name = kmalloc(short_name_size, GFP_KERNEL); + if (!short_name) + return -ENOMEM; + + ucs2_as_utf8(short_name, variable_name, short_name_size); + + /* This is ugly, but necessary to separate one vendor's + private variables from another's. */ + short_name[utf8_name_size] = '-'; + efi_guid_to_str(&new_var->var.VendorGuid, + short_name + utf8_name_size + 1); + + new_var->kobj.kset = efivars_kset; + + ret = kobject_init_and_add(&new_var->kobj, &efivar_ktype, + NULL, "%s", short_name); + kfree(short_name); + if (ret) { + kobject_put(&new_var->kobj); + return ret; + } + + kobject_uevent(&new_var->kobj, KOBJ_ADD); + if (efivar_entry_add(new_var, &efivar_sysfs_list)) { + efivar_unregister(new_var); + return -EINTR; + } + + return 0; +} + +static int +create_efivars_bin_attributes(void) +{ + struct bin_attribute *attr; + int error; + + /* new_var */ + attr = kzalloc(sizeof(*attr), GFP_KERNEL); + if (!attr) + return -ENOMEM; + + attr->attr.name = "new_var"; + attr->attr.mode = 0200; + attr->write = efivar_create; + efivars_new_var = attr; + + /* del_var */ + attr = kzalloc(sizeof(*attr), GFP_KERNEL); + if (!attr) { + error = -ENOMEM; + goto out_free; + } + attr->attr.name = "del_var"; + attr->attr.mode = 0200; + attr->write = efivar_delete; + efivars_del_var = attr; + + sysfs_bin_attr_init(efivars_new_var); + sysfs_bin_attr_init(efivars_del_var); + + /* Register */ + error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var); + if (error) { + printk(KERN_ERR "efivars: unable to create new_var sysfs file" + " due to error %d\n", error); + goto out_free; + } + + error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var); + if (error) { + printk(KERN_ERR "efivars: unable to create del_var sysfs file" + " due to error %d\n", error); + sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var); + goto out_free; + } + + return 0; +out_free: + kfree(efivars_del_var); + efivars_del_var = NULL; + kfree(efivars_new_var); + efivars_new_var = NULL; + return error; +} + +static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor, + unsigned long name_size, void *data) +{ + struct efivar_entry *entry; + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + + memcpy(entry->var.VariableName, name, name_size); + memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); + + efivar_create_sysfs_entry(entry); + + return 0; +} + +static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data) +{ + int err = efivar_entry_remove(entry); + + if (err) + return err; + efivar_unregister(entry); + return 0; +} + +static void efivars_sysfs_exit(void) +{ + /* Remove all entries and destroy */ + int err; + + err = __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, + NULL, NULL); + if (err) { + pr_err("efivars: Failed to destroy sysfs entries\n"); + return; + } + + if (efivars_new_var) + sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var); + if (efivars_del_var) + sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var); + kfree(efivars_new_var); + kfree(efivars_del_var); + kset_unregister(efivars_kset); +} + +static int efivars_sysfs_init(void) +{ + struct kobject *parent_kobj = efivars_kobject(); + int error = 0; + + /* No efivars has been registered yet */ + if (!parent_kobj || !efivar_supports_writes()) + return 0; + + printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION, + EFIVARS_DATE); + + efivars_kset = kset_create_and_add("vars", NULL, parent_kobj); + if (!efivars_kset) { + printk(KERN_ERR "efivars: Subsystem registration failed.\n"); + return -ENOMEM; + } + + efivar_init(efivars_sysfs_callback, NULL, true, &efivar_sysfs_list); + + error = create_efivars_bin_attributes(); + if (error) { + efivars_sysfs_exit(); + return error; + } + + return 0; +} + +module_init(efivars_sysfs_init); +module_exit(efivars_sysfs_exit); 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