2013-02-08 09:27:24 -07:00
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/*
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* Copyright (C) 2012 Red Hat, Inc.
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* Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.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 version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/efi.h>
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#include <linux/fs.h>
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#include <linux/ctype.h>
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2013-05-01 18:51:54 -06:00
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#include <linux/slab.h>
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2013-02-08 09:27:24 -07:00
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#include "internal.h"
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struct inode *efivarfs_get_inode(struct super_block *sb,
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const struct inode *dir, int mode, dev_t dev)
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{
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struct inode *inode = new_inode(sb);
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if (inode) {
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inode->i_ino = get_next_ino();
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inode->i_mode = mode;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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switch (mode & S_IFMT) {
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case S_IFREG:
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inode->i_fop = &efivarfs_file_operations;
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break;
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case S_IFDIR:
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inode->i_op = &efivarfs_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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inc_nlink(inode);
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break;
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}
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}
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return inode;
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}
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/*
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* Return true if 'str' is a valid efivarfs filename of the form,
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*
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* VariableName-12345678-1234-1234-1234-1234567891bc
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*/
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bool efivarfs_valid_name(const char *str, int len)
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{
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static const char dashes[EFI_VARIABLE_GUID_LEN] = {
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[8] = 1, [13] = 1, [18] = 1, [23] = 1
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};
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const char *s = str + len - EFI_VARIABLE_GUID_LEN;
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int i;
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/*
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* We need a GUID, plus at least one letter for the variable name,
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* plus the '-' separator
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*/
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if (len < EFI_VARIABLE_GUID_LEN + 2)
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return false;
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/* GUID must be preceded by a '-' */
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if (*(s - 1) != '-')
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return false;
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/*
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* Validate that 's' is of the correct format, e.g.
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*
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* 12345678-1234-1234-1234-123456789abc
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*/
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for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) {
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if (dashes[i]) {
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if (*s++ != '-')
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return false;
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} else {
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if (!isxdigit(*s++))
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return false;
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}
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}
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return true;
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}
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static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
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{
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guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
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guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
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guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
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guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
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guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
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guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
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guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
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guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
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guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
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guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
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guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
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guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
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guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
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guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
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guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
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guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
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}
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static int efivarfs_create(struct inode *dir, struct dentry *dentry,
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umode_t mode, bool excl)
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{
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struct inode *inode;
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struct efivar_entry *var;
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int namelen, i = 0, err = 0;
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if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
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return -EINVAL;
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inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
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if (!inode)
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return -ENOMEM;
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var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
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if (!var) {
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err = -ENOMEM;
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goto out;
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}
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/* length of the variable name itself: remove GUID and separator */
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namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
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efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
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&var->var.VendorGuid);
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for (i = 0; i < namelen; i++)
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var->var.VariableName[i] = dentry->d_name.name[i];
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var->var.VariableName[i] = '\0';
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inode->i_private = var;
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efivar_entry_add(var, &efivarfs_list);
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d_instantiate(dentry, inode);
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dget(dentry);
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out:
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if (err) {
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kfree(var);
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iput(inode);
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}
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return err;
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}
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static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
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{
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2015-03-17 16:25:59 -06:00
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struct efivar_entry *var = d_inode(dentry)->i_private;
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2013-02-08 09:27:24 -07:00
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if (efivar_entry_delete(var))
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return -EINVAL;
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2015-03-17 16:25:59 -06:00
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drop_nlink(d_inode(dentry));
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2013-02-08 09:27:24 -07:00
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dput(dentry);
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return 0;
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};
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const struct inode_operations efivarfs_dir_inode_operations = {
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2013-07-14 07:48:35 -06:00
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.lookup = simple_lookup,
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2013-02-08 09:27:24 -07:00
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.unlink = efivarfs_unlink,
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.create = efivarfs_create,
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};
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