![Sylvain Chouleur](/assets/img/avatar_default.png)
All efivars operations are protected by a spinlock which prevents interruptions and preemption. This is too restricted, we just need a lock preventing concurrency. The idea is to use a semaphore of count 1 and to have two ways of locking, depending on the context: - In interrupt context, we call down_trylock(), if it fails we return an error - In normal context, we call down_interruptible() We don't use a mutex here because the mutex_trylock() function must not be called from interrupt context, whereas the down_trylock() can. Signed-off-by: Sylvain Chouleur <sylvain.chouleur@intel.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Sylvain Chouleur <sylvain.chouleur@gmail.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
1188 lines
31 KiB
C
1188 lines
31 KiB
C
/*
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* Originally from efivars.c
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*
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* Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
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* Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/capability.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/smp.h>
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#include <linux/efi.h>
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#include <linux/sysfs.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/ctype.h>
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#include <linux/ucs2_string.h>
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/* Private pointer to registered efivars */
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static struct efivars *__efivars;
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/*
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* efivars_lock protects three things:
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* 1) efivarfs_list and efivars_sysfs_list
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* 2) ->ops calls
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* 3) (un)registration of __efivars
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*/
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static DEFINE_SEMAPHORE(efivars_lock);
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static bool efivar_wq_enabled = true;
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DECLARE_WORK(efivar_work, NULL);
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EXPORT_SYMBOL_GPL(efivar_work);
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static bool
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validate_device_path(efi_char16_t *var_name, int match, u8 *buffer,
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unsigned long len)
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{
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struct efi_generic_dev_path *node;
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int offset = 0;
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node = (struct efi_generic_dev_path *)buffer;
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if (len < sizeof(*node))
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return false;
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while (offset <= len - sizeof(*node) &&
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node->length >= sizeof(*node) &&
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node->length <= len - offset) {
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offset += node->length;
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if ((node->type == EFI_DEV_END_PATH ||
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node->type == EFI_DEV_END_PATH2) &&
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node->sub_type == EFI_DEV_END_ENTIRE)
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return true;
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node = (struct efi_generic_dev_path *)(buffer + offset);
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}
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/*
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* If we're here then either node->length pointed past the end
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* of the buffer or we reached the end of the buffer without
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* finding a device path end node.
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*/
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return false;
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}
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static bool
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validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer,
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unsigned long len)
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{
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/* An array of 16-bit integers */
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if ((len % 2) != 0)
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return false;
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return true;
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}
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static bool
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validate_load_option(efi_char16_t *var_name, int match, u8 *buffer,
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unsigned long len)
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{
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u16 filepathlength;
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int i, desclength = 0, namelen;
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namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN);
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/* Either "Boot" or "Driver" followed by four digits of hex */
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for (i = match; i < match+4; i++) {
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if (var_name[i] > 127 ||
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hex_to_bin(var_name[i] & 0xff) < 0)
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return true;
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}
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/* Reject it if there's 4 digits of hex and then further content */
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if (namelen > match + 4)
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return false;
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/* A valid entry must be at least 8 bytes */
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if (len < 8)
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return false;
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filepathlength = buffer[4] | buffer[5] << 8;
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/*
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* There's no stored length for the description, so it has to be
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* found by hand
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*/
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desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
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/* Each boot entry must have a descriptor */
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if (!desclength)
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return false;
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/*
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* If the sum of the length of the description, the claimed filepath
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* length and the original header are greater than the length of the
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* variable, it's malformed
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*/
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if ((desclength + filepathlength + 6) > len)
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return false;
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/*
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* And, finally, check the filepath
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*/
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return validate_device_path(var_name, match, buffer + desclength + 6,
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filepathlength);
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}
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static bool
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validate_uint16(efi_char16_t *var_name, int match, u8 *buffer,
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unsigned long len)
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{
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/* A single 16-bit integer */
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if (len != 2)
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return false;
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return true;
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}
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static bool
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validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer,
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unsigned long len)
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{
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int i;
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for (i = 0; i < len; i++) {
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if (buffer[i] > 127)
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return false;
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if (buffer[i] == 0)
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return true;
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}
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return false;
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}
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struct variable_validate {
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efi_guid_t vendor;
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char *name;
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bool (*validate)(efi_char16_t *var_name, int match, u8 *data,
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unsigned long len);
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};
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/*
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* This is the list of variables we need to validate, as well as the
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* whitelist for what we think is safe not to default to immutable.
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*
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* If it has a validate() method that's not NULL, it'll go into the
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* validation routine. If not, it is assumed valid, but still used for
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* whitelisting.
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*
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* Note that it's sorted by {vendor,name}, but globbed names must come after
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* any other name with the same prefix.
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*/
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static const struct variable_validate variable_validate[] = {
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{ EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 },
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{ EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order },
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{ EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option },
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{ EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order },
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{ EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option },
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{ EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path },
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{ EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path },
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{ EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path },
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{ EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path },
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{ EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path },
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{ EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path },
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{ EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string },
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{ EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL },
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{ EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string },
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{ EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 },
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{ LINUX_EFI_CRASH_GUID, "*", NULL },
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{ NULL_GUID, "", NULL },
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};
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/*
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* Check if @var_name matches the pattern given in @match_name.
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*
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* @var_name: an array of @len non-NUL characters.
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* @match_name: a NUL-terminated pattern string, optionally ending in "*". A
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* final "*" character matches any trailing characters @var_name,
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* including the case when there are none left in @var_name.
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* @match: on output, the number of non-wildcard characters in @match_name
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* that @var_name matches, regardless of the return value.
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* @return: whether @var_name fully matches @match_name.
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*/
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static bool
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variable_matches(const char *var_name, size_t len, const char *match_name,
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int *match)
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{
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for (*match = 0; ; (*match)++) {
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char c = match_name[*match];
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switch (c) {
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case '*':
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/* Wildcard in @match_name means we've matched. */
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return true;
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case '\0':
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/* @match_name has ended. Has @var_name too? */
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return (*match == len);
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default:
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/*
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* We've reached a non-wildcard char in @match_name.
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* Continue only if there's an identical character in
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* @var_name.
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*/
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if (*match < len && c == var_name[*match])
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continue;
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return false;
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}
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}
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}
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bool
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efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
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unsigned long data_size)
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{
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int i;
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unsigned long utf8_size;
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u8 *utf8_name;
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utf8_size = ucs2_utf8size(var_name);
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utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL);
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if (!utf8_name)
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return false;
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ucs2_as_utf8(utf8_name, var_name, utf8_size);
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utf8_name[utf8_size] = '\0';
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for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
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const char *name = variable_validate[i].name;
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int match = 0;
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if (efi_guidcmp(vendor, variable_validate[i].vendor))
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continue;
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if (variable_matches(utf8_name, utf8_size+1, name, &match)) {
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if (variable_validate[i].validate == NULL)
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break;
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kfree(utf8_name);
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return variable_validate[i].validate(var_name, match,
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data, data_size);
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}
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}
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kfree(utf8_name);
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return true;
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}
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EXPORT_SYMBOL_GPL(efivar_validate);
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bool
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efivar_variable_is_removable(efi_guid_t vendor, const char *var_name,
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size_t len)
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{
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int i;
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bool found = false;
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int match = 0;
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/*
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* Check if our variable is in the validated variables list
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*/
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for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
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if (efi_guidcmp(variable_validate[i].vendor, vendor))
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continue;
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if (variable_matches(var_name, len,
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variable_validate[i].name, &match)) {
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found = true;
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break;
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}
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}
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/*
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* If it's in our list, it is removable.
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*/
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return found;
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}
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EXPORT_SYMBOL_GPL(efivar_variable_is_removable);
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static efi_status_t
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check_var_size(u32 attributes, unsigned long size)
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{
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const struct efivar_operations *fops = __efivars->ops;
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if (!fops->query_variable_store)
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return EFI_UNSUPPORTED;
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return fops->query_variable_store(attributes, size, false);
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}
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static efi_status_t
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check_var_size_nonblocking(u32 attributes, unsigned long size)
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{
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const struct efivar_operations *fops = __efivars->ops;
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if (!fops->query_variable_store)
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return EFI_UNSUPPORTED;
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return fops->query_variable_store(attributes, size, true);
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}
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static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
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struct list_head *head)
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{
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struct efivar_entry *entry, *n;
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unsigned long strsize1, strsize2;
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bool found = false;
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strsize1 = ucs2_strsize(variable_name, 1024);
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list_for_each_entry_safe(entry, n, head, list) {
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strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
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if (strsize1 == strsize2 &&
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!memcmp(variable_name, &(entry->var.VariableName),
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strsize2) &&
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!efi_guidcmp(entry->var.VendorGuid,
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*vendor)) {
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found = true;
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break;
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}
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}
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return found;
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}
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/*
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* Returns the size of variable_name, in bytes, including the
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* terminating NULL character, or variable_name_size if no NULL
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* character is found among the first variable_name_size bytes.
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*/
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static unsigned long var_name_strnsize(efi_char16_t *variable_name,
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unsigned long variable_name_size)
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{
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unsigned long len;
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efi_char16_t c;
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/*
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* The variable name is, by definition, a NULL-terminated
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* string, so make absolutely sure that variable_name_size is
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* the value we expect it to be. If not, return the real size.
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*/
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for (len = 2; len <= variable_name_size; len += sizeof(c)) {
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c = variable_name[(len / sizeof(c)) - 1];
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if (!c)
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break;
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}
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return min(len, variable_name_size);
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}
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/*
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* Print a warning when duplicate EFI variables are encountered and
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* disable the sysfs workqueue since the firmware is buggy.
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*/
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static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
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unsigned long len16)
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{
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size_t i, len8 = len16 / sizeof(efi_char16_t);
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char *str8;
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/*
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* Disable the workqueue since the algorithm it uses for
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* detecting new variables won't work with this buggy
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* implementation of GetNextVariableName().
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*/
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efivar_wq_enabled = false;
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str8 = kzalloc(len8, GFP_KERNEL);
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if (!str8)
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return;
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for (i = 0; i < len8; i++)
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str8[i] = str16[i];
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printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
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str8, vendor_guid);
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kfree(str8);
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}
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/**
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* efivar_init - build the initial list of EFI variables
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* @func: callback function to invoke for every variable
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* @data: function-specific data to pass to @func
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* @atomic: do we need to execute the @func-loop atomically?
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* @duplicates: error if we encounter duplicates on @head?
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* @head: initialised head of variable list
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*
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* Get every EFI variable from the firmware and invoke @func. @func
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* should call efivar_entry_add() to build the list of variables.
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*
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* Returns 0 on success, or a kernel error code on failure.
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*/
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int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
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void *data, bool duplicates, struct list_head *head)
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{
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const struct efivar_operations *ops = __efivars->ops;
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unsigned long variable_name_size = 1024;
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efi_char16_t *variable_name;
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efi_status_t status;
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efi_guid_t vendor_guid;
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int err = 0;
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variable_name = kzalloc(variable_name_size, GFP_KERNEL);
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if (!variable_name) {
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printk(KERN_ERR "efivars: Memory allocation failed.\n");
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return -ENOMEM;
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}
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|
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if (down_interruptible(&efivars_lock)) {
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err = -EINTR;
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goto free;
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}
|
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|
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/*
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* Per EFI spec, the maximum storage allocated for both
|
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* the variable name and variable data is 1024 bytes.
|
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*/
|
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do {
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variable_name_size = 1024;
|
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|
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status = ops->get_next_variable(&variable_name_size,
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variable_name,
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&vendor_guid);
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switch (status) {
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case EFI_SUCCESS:
|
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if (duplicates)
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up(&efivars_lock);
|
|
|
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variable_name_size = var_name_strnsize(variable_name,
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variable_name_size);
|
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|
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/*
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* Some firmware implementations return the
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* same variable name on multiple calls to
|
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* get_next_variable(). Terminate the loop
|
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* immediately as there is no guarantee that
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* we'll ever see a different variable name,
|
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* and may end up looping here forever.
|
|
*/
|
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if (duplicates &&
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variable_is_present(variable_name, &vendor_guid,
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head)) {
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dup_variable_bug(variable_name, &vendor_guid,
|
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variable_name_size);
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status = EFI_NOT_FOUND;
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} else {
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err = func(variable_name, vendor_guid,
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variable_name_size, data);
|
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if (err)
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status = EFI_NOT_FOUND;
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}
|
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|
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if (duplicates) {
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if (down_interruptible(&efivars_lock)) {
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err = -EINTR;
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goto free;
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}
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}
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break;
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case EFI_NOT_FOUND:
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break;
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default:
|
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printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
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status);
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status = EFI_NOT_FOUND;
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break;
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}
|
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|
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} while (status != EFI_NOT_FOUND);
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|
|
up(&efivars_lock);
|
|
free:
|
|
kfree(variable_name);
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_init);
|
|
|
|
/**
|
|
* efivar_entry_add - add entry to variable list
|
|
* @entry: entry to add to list
|
|
* @head: list head
|
|
*
|
|
* Returns 0 on success, or a kernel error code on failure.
|
|
*/
|
|
int efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
|
|
{
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
list_add(&entry->list, head);
|
|
up(&efivars_lock);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_add);
|
|
|
|
/**
|
|
* efivar_entry_remove - remove entry from variable list
|
|
* @entry: entry to remove from list
|
|
*
|
|
* Returns 0 on success, or a kernel error code on failure.
|
|
*/
|
|
int efivar_entry_remove(struct efivar_entry *entry)
|
|
{
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
list_del(&entry->list);
|
|
up(&efivars_lock);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_remove);
|
|
|
|
/*
|
|
* efivar_entry_list_del_unlock - remove entry from variable list
|
|
* @entry: entry to remove
|
|
*
|
|
* Remove @entry from the variable list and release the list lock.
|
|
*
|
|
* NOTE: slightly weird locking semantics here - we expect to be
|
|
* called with the efivars lock already held, and we release it before
|
|
* returning. This is because this function is usually called after
|
|
* set_variable() while the lock is still held.
|
|
*/
|
|
static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
|
|
{
|
|
list_del(&entry->list);
|
|
up(&efivars_lock);
|
|
}
|
|
|
|
/**
|
|
* __efivar_entry_delete - delete an EFI variable
|
|
* @entry: entry containing EFI variable to delete
|
|
*
|
|
* Delete the variable from the firmware but leave @entry on the
|
|
* variable list.
|
|
*
|
|
* This function differs from efivar_entry_delete() because it does
|
|
* not remove @entry from the variable list. Also, it is safe to be
|
|
* called from within a efivar_entry_iter_begin() and
|
|
* efivar_entry_iter_end() region, unlike efivar_entry_delete().
|
|
*
|
|
* Returns 0 on success, or a converted EFI status code if
|
|
* set_variable() fails.
|
|
*/
|
|
int __efivar_entry_delete(struct efivar_entry *entry)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_status_t status;
|
|
|
|
status = ops->set_variable(entry->var.VariableName,
|
|
&entry->var.VendorGuid,
|
|
0, 0, NULL);
|
|
|
|
return efi_status_to_err(status);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__efivar_entry_delete);
|
|
|
|
/**
|
|
* efivar_entry_delete - delete variable and remove entry from list
|
|
* @entry: entry containing variable to delete
|
|
*
|
|
* Delete the variable from the firmware and remove @entry from the
|
|
* variable list. It is the caller's responsibility to free @entry
|
|
* once we return.
|
|
*
|
|
* Returns 0 on success, -EINTR if we can't grab the semaphore,
|
|
* converted EFI status code if set_variable() fails.
|
|
*/
|
|
int efivar_entry_delete(struct efivar_entry *entry)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_status_t status;
|
|
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
|
|
status = ops->set_variable(entry->var.VariableName,
|
|
&entry->var.VendorGuid,
|
|
0, 0, NULL);
|
|
if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
|
|
up(&efivars_lock);
|
|
return efi_status_to_err(status);
|
|
}
|
|
|
|
efivar_entry_list_del_unlock(entry);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_delete);
|
|
|
|
/**
|
|
* efivar_entry_set - call set_variable()
|
|
* @entry: entry containing the EFI variable to write
|
|
* @attributes: variable attributes
|
|
* @size: size of @data buffer
|
|
* @data: buffer containing variable data
|
|
* @head: head of variable list
|
|
*
|
|
* Calls set_variable() for an EFI variable. If creating a new EFI
|
|
* variable, this function is usually followed by efivar_entry_add().
|
|
*
|
|
* Before writing the variable, the remaining EFI variable storage
|
|
* space is checked to ensure there is enough room available.
|
|
*
|
|
* If @head is not NULL a lookup is performed to determine whether
|
|
* the entry is already on the list.
|
|
*
|
|
* Returns 0 on success, -EINTR if we can't grab the semaphore,
|
|
* -EEXIST if a lookup is performed and the entry already exists on
|
|
* the list, or a converted EFI status code if set_variable() fails.
|
|
*/
|
|
int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
|
|
unsigned long size, void *data, struct list_head *head)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_status_t status;
|
|
efi_char16_t *name = entry->var.VariableName;
|
|
efi_guid_t vendor = entry->var.VendorGuid;
|
|
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
if (head && efivar_entry_find(name, vendor, head, false)) {
|
|
up(&efivars_lock);
|
|
return -EEXIST;
|
|
}
|
|
|
|
status = check_var_size(attributes, size + ucs2_strsize(name, 1024));
|
|
if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
|
|
status = ops->set_variable(name, &vendor,
|
|
attributes, size, data);
|
|
|
|
up(&efivars_lock);
|
|
|
|
return efi_status_to_err(status);
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_set);
|
|
|
|
/*
|
|
* efivar_entry_set_nonblocking - call set_variable_nonblocking()
|
|
*
|
|
* This function is guaranteed to not block and is suitable for calling
|
|
* from crash/panic handlers.
|
|
*
|
|
* Crucially, this function will not block if it cannot acquire
|
|
* efivars_lock. Instead, it returns -EBUSY.
|
|
*/
|
|
static int
|
|
efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor,
|
|
u32 attributes, unsigned long size, void *data)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_status_t status;
|
|
|
|
if (down_trylock(&efivars_lock))
|
|
return -EBUSY;
|
|
|
|
status = check_var_size_nonblocking(attributes,
|
|
size + ucs2_strsize(name, 1024));
|
|
if (status != EFI_SUCCESS) {
|
|
up(&efivars_lock);
|
|
return -ENOSPC;
|
|
}
|
|
|
|
status = ops->set_variable_nonblocking(name, &vendor, attributes,
|
|
size, data);
|
|
|
|
up(&efivars_lock);
|
|
return efi_status_to_err(status);
|
|
}
|
|
|
|
/**
|
|
* efivar_entry_set_safe - call set_variable() if enough space in firmware
|
|
* @name: buffer containing the variable name
|
|
* @vendor: variable vendor guid
|
|
* @attributes: variable attributes
|
|
* @block: can we block in this context?
|
|
* @size: size of @data buffer
|
|
* @data: buffer containing variable data
|
|
*
|
|
* Ensures there is enough free storage in the firmware for this variable, and
|
|
* if so, calls set_variable(). If creating a new EFI variable, this function
|
|
* is usually followed by efivar_entry_add().
|
|
*
|
|
* Returns 0 on success, -ENOSPC if the firmware does not have enough
|
|
* space for set_variable() to succeed, or a converted EFI status code
|
|
* if set_variable() fails.
|
|
*/
|
|
int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes,
|
|
bool block, unsigned long size, void *data)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_status_t status;
|
|
|
|
if (!ops->query_variable_store)
|
|
return -ENOSYS;
|
|
|
|
/*
|
|
* If the EFI variable backend provides a non-blocking
|
|
* ->set_variable() operation and we're in a context where we
|
|
* cannot block, then we need to use it to avoid live-locks,
|
|
* since the implication is that the regular ->set_variable()
|
|
* will block.
|
|
*
|
|
* If no ->set_variable_nonblocking() is provided then
|
|
* ->set_variable() is assumed to be non-blocking.
|
|
*/
|
|
if (!block && ops->set_variable_nonblocking)
|
|
return efivar_entry_set_nonblocking(name, vendor, attributes,
|
|
size, data);
|
|
|
|
if (!block) {
|
|
if (down_trylock(&efivars_lock))
|
|
return -EBUSY;
|
|
} else {
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
}
|
|
|
|
status = check_var_size(attributes, size + ucs2_strsize(name, 1024));
|
|
if (status != EFI_SUCCESS) {
|
|
up(&efivars_lock);
|
|
return -ENOSPC;
|
|
}
|
|
|
|
status = ops->set_variable(name, &vendor, attributes, size, data);
|
|
|
|
up(&efivars_lock);
|
|
|
|
return efi_status_to_err(status);
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_set_safe);
|
|
|
|
/**
|
|
* efivar_entry_find - search for an entry
|
|
* @name: the EFI variable name
|
|
* @guid: the EFI variable vendor's guid
|
|
* @head: head of the variable list
|
|
* @remove: should we remove the entry from the list?
|
|
*
|
|
* Search for an entry on the variable list that has the EFI variable
|
|
* name @name and vendor guid @guid. If an entry is found on the list
|
|
* and @remove is true, the entry is removed from the list.
|
|
*
|
|
* The caller MUST call efivar_entry_iter_begin() and
|
|
* efivar_entry_iter_end() before and after the invocation of this
|
|
* function, respectively.
|
|
*
|
|
* Returns the entry if found on the list, %NULL otherwise.
|
|
*/
|
|
struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
|
|
struct list_head *head, bool remove)
|
|
{
|
|
struct efivar_entry *entry, *n;
|
|
int strsize1, strsize2;
|
|
bool found = false;
|
|
|
|
list_for_each_entry_safe(entry, n, head, list) {
|
|
strsize1 = ucs2_strsize(name, 1024);
|
|
strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
|
|
if (strsize1 == strsize2 &&
|
|
!memcmp(name, &(entry->var.VariableName), strsize1) &&
|
|
!efi_guidcmp(guid, entry->var.VendorGuid)) {
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!found)
|
|
return NULL;
|
|
|
|
if (remove) {
|
|
if (entry->scanning) {
|
|
/*
|
|
* The entry will be deleted
|
|
* after scanning is completed.
|
|
*/
|
|
entry->deleting = true;
|
|
} else
|
|
list_del(&entry->list);
|
|
}
|
|
|
|
return entry;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_find);
|
|
|
|
/**
|
|
* efivar_entry_size - obtain the size of a variable
|
|
* @entry: entry for this variable
|
|
* @size: location to store the variable's size
|
|
*/
|
|
int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_status_t status;
|
|
|
|
*size = 0;
|
|
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
status = ops->get_variable(entry->var.VariableName,
|
|
&entry->var.VendorGuid, NULL, size, NULL);
|
|
up(&efivars_lock);
|
|
|
|
if (status != EFI_BUFFER_TOO_SMALL)
|
|
return efi_status_to_err(status);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_size);
|
|
|
|
/**
|
|
* __efivar_entry_get - call get_variable()
|
|
* @entry: read data for this variable
|
|
* @attributes: variable attributes
|
|
* @size: size of @data buffer
|
|
* @data: buffer to store variable data
|
|
*
|
|
* The caller MUST call efivar_entry_iter_begin() and
|
|
* efivar_entry_iter_end() before and after the invocation of this
|
|
* function, respectively.
|
|
*/
|
|
int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
|
|
unsigned long *size, void *data)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_status_t status;
|
|
|
|
status = ops->get_variable(entry->var.VariableName,
|
|
&entry->var.VendorGuid,
|
|
attributes, size, data);
|
|
|
|
return efi_status_to_err(status);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__efivar_entry_get);
|
|
|
|
/**
|
|
* efivar_entry_get - call get_variable()
|
|
* @entry: read data for this variable
|
|
* @attributes: variable attributes
|
|
* @size: size of @data buffer
|
|
* @data: buffer to store variable data
|
|
*/
|
|
int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
|
|
unsigned long *size, void *data)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_status_t status;
|
|
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
status = ops->get_variable(entry->var.VariableName,
|
|
&entry->var.VendorGuid,
|
|
attributes, size, data);
|
|
up(&efivars_lock);
|
|
|
|
return efi_status_to_err(status);
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_get);
|
|
|
|
/**
|
|
* efivar_entry_set_get_size - call set_variable() and get new size (atomic)
|
|
* @entry: entry containing variable to set and get
|
|
* @attributes: attributes of variable to be written
|
|
* @size: size of data buffer
|
|
* @data: buffer containing data to write
|
|
* @set: did the set_variable() call succeed?
|
|
*
|
|
* This is a pretty special (complex) function. See efivarfs_file_write().
|
|
*
|
|
* Atomically call set_variable() for @entry and if the call is
|
|
* successful, return the new size of the variable from get_variable()
|
|
* in @size. The success of set_variable() is indicated by @set.
|
|
*
|
|
* Returns 0 on success, -EINVAL if the variable data is invalid,
|
|
* -ENOSPC if the firmware does not have enough available space, or a
|
|
* converted EFI status code if either of set_variable() or
|
|
* get_variable() fail.
|
|
*
|
|
* If the EFI variable does not exist when calling set_variable()
|
|
* (EFI_NOT_FOUND), @entry is removed from the variable list.
|
|
*/
|
|
int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
|
|
unsigned long *size, void *data, bool *set)
|
|
{
|
|
const struct efivar_operations *ops = __efivars->ops;
|
|
efi_char16_t *name = entry->var.VariableName;
|
|
efi_guid_t *vendor = &entry->var.VendorGuid;
|
|
efi_status_t status;
|
|
int err;
|
|
|
|
*set = false;
|
|
|
|
if (efivar_validate(*vendor, name, data, *size) == false)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* The lock here protects the get_variable call, the conditional
|
|
* set_variable call, and removal of the variable from the efivars
|
|
* list (in the case of an authenticated delete).
|
|
*/
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
|
|
/*
|
|
* Ensure that the available space hasn't shrunk below the safe level
|
|
*/
|
|
status = check_var_size(attributes, *size + ucs2_strsize(name, 1024));
|
|
if (status != EFI_SUCCESS) {
|
|
if (status != EFI_UNSUPPORTED) {
|
|
err = efi_status_to_err(status);
|
|
goto out;
|
|
}
|
|
|
|
if (*size > 65536) {
|
|
err = -ENOSPC;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
status = ops->set_variable(name, vendor, attributes, *size, data);
|
|
if (status != EFI_SUCCESS) {
|
|
err = efi_status_to_err(status);
|
|
goto out;
|
|
}
|
|
|
|
*set = true;
|
|
|
|
/*
|
|
* Writing to the variable may have caused a change in size (which
|
|
* could either be an append or an overwrite), or the variable to be
|
|
* deleted. Perform a GetVariable() so we can tell what actually
|
|
* happened.
|
|
*/
|
|
*size = 0;
|
|
status = ops->get_variable(entry->var.VariableName,
|
|
&entry->var.VendorGuid,
|
|
NULL, size, NULL);
|
|
|
|
if (status == EFI_NOT_FOUND)
|
|
efivar_entry_list_del_unlock(entry);
|
|
else
|
|
up(&efivars_lock);
|
|
|
|
if (status && status != EFI_BUFFER_TOO_SMALL)
|
|
return efi_status_to_err(status);
|
|
|
|
return 0;
|
|
|
|
out:
|
|
up(&efivars_lock);
|
|
return err;
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_set_get_size);
|
|
|
|
/**
|
|
* efivar_entry_iter_begin - begin iterating the variable list
|
|
*
|
|
* Lock the variable list to prevent entry insertion and removal until
|
|
* efivar_entry_iter_end() is called. This function is usually used in
|
|
* conjunction with __efivar_entry_iter() or efivar_entry_iter().
|
|
*/
|
|
int efivar_entry_iter_begin(void)
|
|
{
|
|
return down_interruptible(&efivars_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_iter_begin);
|
|
|
|
/**
|
|
* efivar_entry_iter_end - finish iterating the variable list
|
|
*
|
|
* Unlock the variable list and allow modifications to the list again.
|
|
*/
|
|
void efivar_entry_iter_end(void)
|
|
{
|
|
up(&efivars_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_iter_end);
|
|
|
|
/**
|
|
* __efivar_entry_iter - iterate over variable list
|
|
* @func: callback function
|
|
* @head: head of the variable list
|
|
* @data: function-specific data to pass to callback
|
|
* @prev: entry to begin iterating from
|
|
*
|
|
* Iterate over the list of EFI variables and call @func with every
|
|
* entry on the list. It is safe for @func to remove entries in the
|
|
* list via efivar_entry_delete().
|
|
*
|
|
* You MUST call efivar_enter_iter_begin() before this function, and
|
|
* efivar_entry_iter_end() afterwards.
|
|
*
|
|
* It is possible to begin iteration from an arbitrary entry within
|
|
* the list by passing @prev. @prev is updated on return to point to
|
|
* the last entry passed to @func. To begin iterating from the
|
|
* beginning of the list @prev must be %NULL.
|
|
*
|
|
* The restrictions for @func are the same as documented for
|
|
* efivar_entry_iter().
|
|
*/
|
|
int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
|
|
struct list_head *head, void *data,
|
|
struct efivar_entry **prev)
|
|
{
|
|
struct efivar_entry *entry, *n;
|
|
int err = 0;
|
|
|
|
if (!prev || !*prev) {
|
|
list_for_each_entry_safe(entry, n, head, list) {
|
|
err = func(entry, data);
|
|
if (err)
|
|
break;
|
|
}
|
|
|
|
if (prev)
|
|
*prev = entry;
|
|
|
|
return err;
|
|
}
|
|
|
|
|
|
list_for_each_entry_safe_continue((*prev), n, head, list) {
|
|
err = func(*prev, data);
|
|
if (err)
|
|
break;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__efivar_entry_iter);
|
|
|
|
/**
|
|
* efivar_entry_iter - iterate over variable list
|
|
* @func: callback function
|
|
* @head: head of variable list
|
|
* @data: function-specific data to pass to callback
|
|
*
|
|
* Iterate over the list of EFI variables and call @func with every
|
|
* entry on the list. It is safe for @func to remove entries in the
|
|
* list via efivar_entry_delete() while iterating.
|
|
*
|
|
* Some notes for the callback function:
|
|
* - a non-zero return value indicates an error and terminates the loop
|
|
* - @func is called from atomic context
|
|
*/
|
|
int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
|
|
struct list_head *head, void *data)
|
|
{
|
|
int err = 0;
|
|
|
|
err = efivar_entry_iter_begin();
|
|
if (err)
|
|
return err;
|
|
err = __efivar_entry_iter(func, head, data, NULL);
|
|
efivar_entry_iter_end();
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_entry_iter);
|
|
|
|
/**
|
|
* efivars_kobject - get the kobject for the registered efivars
|
|
*
|
|
* If efivars_register() has not been called we return NULL,
|
|
* otherwise return the kobject used at registration time.
|
|
*/
|
|
struct kobject *efivars_kobject(void)
|
|
{
|
|
if (!__efivars)
|
|
return NULL;
|
|
|
|
return __efivars->kobject;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivars_kobject);
|
|
|
|
/**
|
|
* efivar_run_worker - schedule the efivar worker thread
|
|
*/
|
|
void efivar_run_worker(void)
|
|
{
|
|
if (efivar_wq_enabled)
|
|
schedule_work(&efivar_work);
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivar_run_worker);
|
|
|
|
/**
|
|
* efivars_register - register an efivars
|
|
* @efivars: efivars to register
|
|
* @ops: efivars operations
|
|
* @kobject: @efivars-specific kobject
|
|
*
|
|
* Only a single efivars can be registered at any time.
|
|
*/
|
|
int efivars_register(struct efivars *efivars,
|
|
const struct efivar_operations *ops,
|
|
struct kobject *kobject)
|
|
{
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
|
|
efivars->ops = ops;
|
|
efivars->kobject = kobject;
|
|
|
|
__efivars = efivars;
|
|
|
|
pr_info("Registered efivars operations\n");
|
|
|
|
up(&efivars_lock);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivars_register);
|
|
|
|
/**
|
|
* efivars_unregister - unregister an efivars
|
|
* @efivars: efivars to unregister
|
|
*
|
|
* The caller must have already removed every entry from the list,
|
|
* failure to do so is an error.
|
|
*/
|
|
int efivars_unregister(struct efivars *efivars)
|
|
{
|
|
int rv;
|
|
|
|
if (down_interruptible(&efivars_lock))
|
|
return -EINTR;
|
|
|
|
if (!__efivars) {
|
|
printk(KERN_ERR "efivars not registered\n");
|
|
rv = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (__efivars != efivars) {
|
|
rv = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
pr_info("Unregistered efivars operations\n");
|
|
__efivars = NULL;
|
|
|
|
rv = 0;
|
|
out:
|
|
up(&efivars_lock);
|
|
return rv;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efivars_unregister);
|