linux/drivers/firmware/efi/efivars.c
Matt Fleming e33655a386 efivars: Add compatibility code for compat tasks
It seems people are using 32-bit efibootmgr on top of 64-bit kernels,
which will currently fail horribly when using the efivars interface,
which is the traditional efibootmgr backend (the other being efivarfs).

Since there is no versioning info in the data structure, figure out when
we need to munge the structure data via judicious use of
is_compat_task().

Cc: Mike Waychison <mikew@google.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2014-04-17 13:53:53 +01:00

755 lines
19 KiB
C

/*
* 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
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Changelog:
*
* 17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
* remove check for efi_enabled in exit
* add MODULE_VERSION
*
* 26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
* minor bug fixes
*
* 21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
* converted driver to export variable information via sysfs
* and moved to drivers/firmware directory
* bumped revision number to v0.07 to reflect conversion & move
*
* 10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
* fix locking per Peter Chubb's findings
*
* 25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
* move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
*
* 12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
* use list_for_each_safe when deleting vars.
* remove ifdef CONFIG_SMP around include <linux/smp.h>
* v0.04 release to linux-ia64@linuxia64.org
*
* 20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
* Moved vars from /proc/efi to /proc/efi/vars, and made
* efi.c own the /proc/efi directory.
* v0.03 release to linux-ia64@linuxia64.org
*
* 26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
* At the request of Stephane, moved ownership of /proc/efi
* to efi.c, and now efivars lives under /proc/efi/vars.
*
* 12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
* Feedback received from Stephane Eranian incorporated.
* efivar_write() checks copy_from_user() return value.
* efivar_read/write() returns proper errno.
* v0.02 release to linux-ia64@linuxia64.org
*
* 26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
* v0.01 release to linux-ia64@linuxia64.org
*/
#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);
LIST_HEAD(efivar_sysfs_list);
EXPORT_SYMBOL_GPL(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_unparse(&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;
char *str = buf;
if (!entry || !buf)
return -EINVAL;
var->DataSize = 1024;
if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
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;
char *str = buf;
if (!entry || !buf)
return -EINVAL;
var->DataSize = 1024;
if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
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;
if (!entry || !buf)
return -EINVAL;
var->DataSize = 1024;
if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
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(name, data, size) == false) {
printk(KERN_ERR "efivars: Malformed variable content\n");
return -EINVAL;
}
return 0;
}
static inline bool is_compat(void)
{
if (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())
return true;
return false;
}
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 (is_compat()) {
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;
size_t size;
if (!entry || !buf)
return 0;
var->DataSize = 1024;
if (efivar_entry_get(entry, &entry->var.Attributes,
&entry->var.DataSize, entry->var.Data))
return -EIO;
if (is_compat()) {
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 = container_of(kobj, struct 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 = is_compat();
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(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 (is_compat()) {
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;
}
efivar_entry_iter_begin();
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 1 on failure, 0 on success
*/
static int
efivar_create_sysfs_entry(struct efivar_entry *new_var)
{
int i, short_name_size;
char *short_name;
unsigned long variable_name_size;
efi_char16_t *variable_name;
variable_name = new_var->var.VariableName;
variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t);
/*
* Length of the variable bytes in ASCII, plus the '-' separator,
* plus the GUID, plus trailing NUL
*/
short_name_size = variable_name_size / sizeof(efi_char16_t)
+ 1 + EFI_VARIABLE_GUID_LEN + 1;
short_name = kzalloc(short_name_size, GFP_KERNEL);
if (!short_name)
return 1;
/* Convert Unicode to normal chars (assume top bits are 0),
ala UTF-8 */
for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
short_name[i] = variable_name[i] & 0xFF;
}
/* This is ugly, but necessary to separate one vendor's
private variables from another's. */
*(short_name + strlen(short_name)) = '-';
efi_guid_unparse(&new_var->var.VendorGuid,
short_name + strlen(short_name));
new_var->kobj.kset = efivars_kset;
i = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
NULL, "%s", short_name);
kfree(short_name);
if (i)
return 1;
kobject_uevent(&new_var->kobj, KOBJ_ADD);
efivar_entry_add(new_var, &efivar_sysfs_list);
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 efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor,
unsigned long name_size, void *data)
{
struct efivar_entry *entry = data;
if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false))
return 0;
memcpy(entry->var.VariableName, name, name_size);
memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
return 1;
}
static void efivar_update_sysfs_entries(struct work_struct *work)
{
struct efivar_entry *entry;
int err;
/* Add new sysfs entries */
while (1) {
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
return;
err = efivar_init(efivar_update_sysfs_entry, entry,
true, false, &efivar_sysfs_list);
if (!err)
break;
efivar_create_sysfs_entry(entry);
}
kfree(entry);
}
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)
{
efivar_entry_remove(entry);
efivar_unregister(entry);
return 0;
}
static void efivars_sysfs_exit(void)
{
/* Remove all entries and destroy */
__efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL);
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);
}
int efivars_sysfs_init(void)
{
struct kobject *parent_kobj = efivars_kobject();
int error = 0;
if (!efi_enabled(EFI_RUNTIME_SERVICES))
return -ENODEV;
/* No efivars has been registered yet */
if (!parent_kobj)
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, false,
true, &efivar_sysfs_list);
error = create_efivars_bin_attributes();
if (error) {
efivars_sysfs_exit();
return error;
}
INIT_WORK(&efivar_work, efivar_update_sysfs_entries);
return 0;
}
EXPORT_SYMBOL_GPL(efivars_sysfs_init);
module_init(efivars_sysfs_init);
module_exit(efivars_sysfs_exit);