1d68772b7SMatt Fleming /* 2d68772b7SMatt Fleming * Copyright (C) 2012 Red Hat, Inc. 3d68772b7SMatt Fleming * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> 4d68772b7SMatt Fleming * 5d68772b7SMatt Fleming * This program is free software; you can redistribute it and/or modify 6d68772b7SMatt Fleming * it under the terms of the GNU General Public License version 2 as 7d68772b7SMatt Fleming * published by the Free Software Foundation. 8d68772b7SMatt Fleming */ 9d68772b7SMatt Fleming 10d68772b7SMatt Fleming #include <linux/efi.h> 11d68772b7SMatt Fleming #include <linux/fs.h> 12d68772b7SMatt Fleming #include <linux/ctype.h> 1320b4fb48SLinus Torvalds #include <linux/slab.h> 14d68772b7SMatt Fleming 15d68772b7SMatt Fleming #include "internal.h" 16d68772b7SMatt Fleming 17d68772b7SMatt Fleming struct inode *efivarfs_get_inode(struct super_block *sb, 18d68772b7SMatt Fleming const struct inode *dir, int mode, dev_t dev) 19d68772b7SMatt Fleming { 20d68772b7SMatt Fleming struct inode *inode = new_inode(sb); 21d68772b7SMatt Fleming 22d68772b7SMatt Fleming if (inode) { 23d68772b7SMatt Fleming inode->i_ino = get_next_ino(); 24d68772b7SMatt Fleming inode->i_mode = mode; 25d68772b7SMatt Fleming inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 26d68772b7SMatt Fleming switch (mode & S_IFMT) { 27d68772b7SMatt Fleming case S_IFREG: 28d68772b7SMatt Fleming inode->i_fop = &efivarfs_file_operations; 29d68772b7SMatt Fleming break; 30d68772b7SMatt Fleming case S_IFDIR: 31d68772b7SMatt Fleming inode->i_op = &efivarfs_dir_inode_operations; 32d68772b7SMatt Fleming inode->i_fop = &simple_dir_operations; 33d68772b7SMatt Fleming inc_nlink(inode); 34d68772b7SMatt Fleming break; 35d68772b7SMatt Fleming } 36d68772b7SMatt Fleming } 37d68772b7SMatt Fleming return inode; 38d68772b7SMatt Fleming } 39d68772b7SMatt Fleming 40d68772b7SMatt Fleming /* 41d68772b7SMatt Fleming * Return true if 'str' is a valid efivarfs filename of the form, 42d68772b7SMatt Fleming * 43d68772b7SMatt Fleming * VariableName-12345678-1234-1234-1234-1234567891bc 44d68772b7SMatt Fleming */ 45d68772b7SMatt Fleming bool efivarfs_valid_name(const char *str, int len) 46d68772b7SMatt Fleming { 47d68772b7SMatt Fleming static const char dashes[EFI_VARIABLE_GUID_LEN] = { 48d68772b7SMatt Fleming [8] = 1, [13] = 1, [18] = 1, [23] = 1 49d68772b7SMatt Fleming }; 50d68772b7SMatt Fleming const char *s = str + len - EFI_VARIABLE_GUID_LEN; 51d68772b7SMatt Fleming int i; 52d68772b7SMatt Fleming 53d68772b7SMatt Fleming /* 54d68772b7SMatt Fleming * We need a GUID, plus at least one letter for the variable name, 55d68772b7SMatt Fleming * plus the '-' separator 56d68772b7SMatt Fleming */ 57d68772b7SMatt Fleming if (len < EFI_VARIABLE_GUID_LEN + 2) 58d68772b7SMatt Fleming return false; 59d68772b7SMatt Fleming 60d68772b7SMatt Fleming /* GUID must be preceded by a '-' */ 61d68772b7SMatt Fleming if (*(s - 1) != '-') 62d68772b7SMatt Fleming return false; 63d68772b7SMatt Fleming 64d68772b7SMatt Fleming /* 65d68772b7SMatt Fleming * Validate that 's' is of the correct format, e.g. 66d68772b7SMatt Fleming * 67d68772b7SMatt Fleming * 12345678-1234-1234-1234-123456789abc 68d68772b7SMatt Fleming */ 69d68772b7SMatt Fleming for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) { 70d68772b7SMatt Fleming if (dashes[i]) { 71d68772b7SMatt Fleming if (*s++ != '-') 72d68772b7SMatt Fleming return false; 73d68772b7SMatt Fleming } else { 74d68772b7SMatt Fleming if (!isxdigit(*s++)) 75d68772b7SMatt Fleming return false; 76d68772b7SMatt Fleming } 77d68772b7SMatt Fleming } 78d68772b7SMatt Fleming 79d68772b7SMatt Fleming return true; 80d68772b7SMatt Fleming } 81d68772b7SMatt Fleming 82d68772b7SMatt Fleming static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid) 83d68772b7SMatt Fleming { 84d68772b7SMatt Fleming guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]); 85d68772b7SMatt Fleming guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]); 86d68772b7SMatt Fleming guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]); 87d68772b7SMatt Fleming guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]); 88d68772b7SMatt Fleming guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]); 89d68772b7SMatt Fleming guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]); 90d68772b7SMatt Fleming guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]); 91d68772b7SMatt Fleming guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]); 92d68772b7SMatt Fleming guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]); 93d68772b7SMatt Fleming guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]); 94d68772b7SMatt Fleming guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]); 95d68772b7SMatt Fleming guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]); 96d68772b7SMatt Fleming guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]); 97d68772b7SMatt Fleming guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]); 98d68772b7SMatt Fleming guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]); 99d68772b7SMatt Fleming guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]); 100d68772b7SMatt Fleming } 101d68772b7SMatt Fleming 102d68772b7SMatt Fleming static int efivarfs_create(struct inode *dir, struct dentry *dentry, 103d68772b7SMatt Fleming umode_t mode, bool excl) 104d68772b7SMatt Fleming { 105d68772b7SMatt Fleming struct inode *inode; 106d68772b7SMatt Fleming struct efivar_entry *var; 107d68772b7SMatt Fleming int namelen, i = 0, err = 0; 108d68772b7SMatt Fleming 109d68772b7SMatt Fleming if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) 110d68772b7SMatt Fleming return -EINVAL; 111d68772b7SMatt Fleming 112d68772b7SMatt Fleming inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0); 113d68772b7SMatt Fleming if (!inode) 114d68772b7SMatt Fleming return -ENOMEM; 115d68772b7SMatt Fleming 116d68772b7SMatt Fleming var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); 117d68772b7SMatt Fleming if (!var) { 118d68772b7SMatt Fleming err = -ENOMEM; 119d68772b7SMatt Fleming goto out; 120d68772b7SMatt Fleming } 121d68772b7SMatt Fleming 122d68772b7SMatt Fleming /* length of the variable name itself: remove GUID and separator */ 123d68772b7SMatt Fleming namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; 124d68772b7SMatt Fleming 125d68772b7SMatt Fleming efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1, 126d68772b7SMatt Fleming &var->var.VendorGuid); 127d68772b7SMatt Fleming 128d68772b7SMatt Fleming for (i = 0; i < namelen; i++) 129d68772b7SMatt Fleming var->var.VariableName[i] = dentry->d_name.name[i]; 130d68772b7SMatt Fleming 131d68772b7SMatt Fleming var->var.VariableName[i] = '\0'; 132d68772b7SMatt Fleming 133d68772b7SMatt Fleming inode->i_private = var; 134d68772b7SMatt Fleming 135d68772b7SMatt Fleming efivar_entry_add(var, &efivarfs_list); 136d68772b7SMatt Fleming d_instantiate(dentry, inode); 137d68772b7SMatt Fleming dget(dentry); 138d68772b7SMatt Fleming out: 139d68772b7SMatt Fleming if (err) { 140d68772b7SMatt Fleming kfree(var); 141d68772b7SMatt Fleming iput(inode); 142d68772b7SMatt Fleming } 143d68772b7SMatt Fleming return err; 144d68772b7SMatt Fleming } 145d68772b7SMatt Fleming 146d68772b7SMatt Fleming static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) 147d68772b7SMatt Fleming { 148d68772b7SMatt Fleming struct efivar_entry *var = dentry->d_inode->i_private; 149d68772b7SMatt Fleming 150d68772b7SMatt Fleming if (efivar_entry_delete(var)) 151d68772b7SMatt Fleming return -EINVAL; 152d68772b7SMatt Fleming 153d68772b7SMatt Fleming drop_nlink(dentry->d_inode); 154d68772b7SMatt Fleming dput(dentry); 155d68772b7SMatt Fleming return 0; 156d68772b7SMatt Fleming }; 157d68772b7SMatt Fleming 158d68772b7SMatt Fleming const struct inode_operations efivarfs_dir_inode_operations = { 1596e8cd2cbSAl Viro .lookup = simple_lookup, 160d68772b7SMatt Fleming .unlink = efivarfs_unlink, 161d68772b7SMatt Fleming .create = efivarfs_create, 162d68772b7SMatt Fleming }; 163