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> 13d68772b7SMatt Fleming 14d68772b7SMatt Fleming #include "internal.h" 15d68772b7SMatt Fleming 16d68772b7SMatt Fleming struct inode *efivarfs_get_inode(struct super_block *sb, 17d68772b7SMatt Fleming const struct inode *dir, int mode, dev_t dev) 18d68772b7SMatt Fleming { 19d68772b7SMatt Fleming struct inode *inode = new_inode(sb); 20d68772b7SMatt Fleming 21d68772b7SMatt Fleming if (inode) { 22d68772b7SMatt Fleming inode->i_ino = get_next_ino(); 23d68772b7SMatt Fleming inode->i_mode = mode; 24d68772b7SMatt Fleming inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 25d68772b7SMatt Fleming switch (mode & S_IFMT) { 26d68772b7SMatt Fleming case S_IFREG: 27d68772b7SMatt Fleming inode->i_fop = &efivarfs_file_operations; 28d68772b7SMatt Fleming break; 29d68772b7SMatt Fleming case S_IFDIR: 30d68772b7SMatt Fleming inode->i_op = &efivarfs_dir_inode_operations; 31d68772b7SMatt Fleming inode->i_fop = &simple_dir_operations; 32d68772b7SMatt Fleming inc_nlink(inode); 33d68772b7SMatt Fleming break; 34d68772b7SMatt Fleming } 35d68772b7SMatt Fleming } 36d68772b7SMatt Fleming return inode; 37d68772b7SMatt Fleming } 38d68772b7SMatt Fleming 39d68772b7SMatt Fleming /* 40d68772b7SMatt Fleming * Return true if 'str' is a valid efivarfs filename of the form, 41d68772b7SMatt Fleming * 42d68772b7SMatt Fleming * VariableName-12345678-1234-1234-1234-1234567891bc 43d68772b7SMatt Fleming */ 44d68772b7SMatt Fleming bool efivarfs_valid_name(const char *str, int len) 45d68772b7SMatt Fleming { 46d68772b7SMatt Fleming static const char dashes[EFI_VARIABLE_GUID_LEN] = { 47d68772b7SMatt Fleming [8] = 1, [13] = 1, [18] = 1, [23] = 1 48d68772b7SMatt Fleming }; 49d68772b7SMatt Fleming const char *s = str + len - EFI_VARIABLE_GUID_LEN; 50d68772b7SMatt Fleming int i; 51d68772b7SMatt Fleming 52d68772b7SMatt Fleming /* 53d68772b7SMatt Fleming * We need a GUID, plus at least one letter for the variable name, 54d68772b7SMatt Fleming * plus the '-' separator 55d68772b7SMatt Fleming */ 56d68772b7SMatt Fleming if (len < EFI_VARIABLE_GUID_LEN + 2) 57d68772b7SMatt Fleming return false; 58d68772b7SMatt Fleming 59d68772b7SMatt Fleming /* GUID must be preceded by a '-' */ 60d68772b7SMatt Fleming if (*(s - 1) != '-') 61d68772b7SMatt Fleming return false; 62d68772b7SMatt Fleming 63d68772b7SMatt Fleming /* 64d68772b7SMatt Fleming * Validate that 's' is of the correct format, e.g. 65d68772b7SMatt Fleming * 66d68772b7SMatt Fleming * 12345678-1234-1234-1234-123456789abc 67d68772b7SMatt Fleming */ 68d68772b7SMatt Fleming for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) { 69d68772b7SMatt Fleming if (dashes[i]) { 70d68772b7SMatt Fleming if (*s++ != '-') 71d68772b7SMatt Fleming return false; 72d68772b7SMatt Fleming } else { 73d68772b7SMatt Fleming if (!isxdigit(*s++)) 74d68772b7SMatt Fleming return false; 75d68772b7SMatt Fleming } 76d68772b7SMatt Fleming } 77d68772b7SMatt Fleming 78d68772b7SMatt Fleming return true; 79d68772b7SMatt Fleming } 80d68772b7SMatt Fleming 81d68772b7SMatt Fleming static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid) 82d68772b7SMatt Fleming { 83d68772b7SMatt Fleming guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]); 84d68772b7SMatt Fleming guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]); 85d68772b7SMatt Fleming guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]); 86d68772b7SMatt Fleming guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]); 87d68772b7SMatt Fleming guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]); 88d68772b7SMatt Fleming guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]); 89d68772b7SMatt Fleming guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]); 90d68772b7SMatt Fleming guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]); 91d68772b7SMatt Fleming guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]); 92d68772b7SMatt Fleming guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]); 93d68772b7SMatt Fleming guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]); 94d68772b7SMatt Fleming guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]); 95d68772b7SMatt Fleming guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]); 96d68772b7SMatt Fleming guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]); 97d68772b7SMatt Fleming guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]); 98d68772b7SMatt Fleming guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]); 99d68772b7SMatt Fleming } 100d68772b7SMatt Fleming 101d68772b7SMatt Fleming static int efivarfs_create(struct inode *dir, struct dentry *dentry, 102d68772b7SMatt Fleming umode_t mode, bool excl) 103d68772b7SMatt Fleming { 104d68772b7SMatt Fleming struct inode *inode; 105d68772b7SMatt Fleming struct efivar_entry *var; 106d68772b7SMatt Fleming int namelen, i = 0, err = 0; 107d68772b7SMatt Fleming 108d68772b7SMatt Fleming if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) 109d68772b7SMatt Fleming return -EINVAL; 110d68772b7SMatt Fleming 111d68772b7SMatt Fleming inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0); 112d68772b7SMatt Fleming if (!inode) 113d68772b7SMatt Fleming return -ENOMEM; 114d68772b7SMatt Fleming 115d68772b7SMatt Fleming var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); 116d68772b7SMatt Fleming if (!var) { 117d68772b7SMatt Fleming err = -ENOMEM; 118d68772b7SMatt Fleming goto out; 119d68772b7SMatt Fleming } 120d68772b7SMatt Fleming 121d68772b7SMatt Fleming /* length of the variable name itself: remove GUID and separator */ 122d68772b7SMatt Fleming namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; 123d68772b7SMatt Fleming 124d68772b7SMatt Fleming efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1, 125d68772b7SMatt Fleming &var->var.VendorGuid); 126d68772b7SMatt Fleming 127d68772b7SMatt Fleming for (i = 0; i < namelen; i++) 128d68772b7SMatt Fleming var->var.VariableName[i] = dentry->d_name.name[i]; 129d68772b7SMatt Fleming 130d68772b7SMatt Fleming var->var.VariableName[i] = '\0'; 131d68772b7SMatt Fleming 132d68772b7SMatt Fleming inode->i_private = var; 133d68772b7SMatt Fleming 134d68772b7SMatt Fleming efivar_entry_add(var, &efivarfs_list); 135d68772b7SMatt Fleming d_instantiate(dentry, inode); 136d68772b7SMatt Fleming dget(dentry); 137d68772b7SMatt Fleming out: 138d68772b7SMatt Fleming if (err) { 139d68772b7SMatt Fleming kfree(var); 140d68772b7SMatt Fleming iput(inode); 141d68772b7SMatt Fleming } 142d68772b7SMatt Fleming return err; 143d68772b7SMatt Fleming } 144d68772b7SMatt Fleming 145d68772b7SMatt Fleming static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) 146d68772b7SMatt Fleming { 147d68772b7SMatt Fleming struct efivar_entry *var = dentry->d_inode->i_private; 148d68772b7SMatt Fleming 149d68772b7SMatt Fleming if (efivar_entry_delete(var)) 150d68772b7SMatt Fleming return -EINVAL; 151d68772b7SMatt Fleming 152d68772b7SMatt Fleming drop_nlink(dentry->d_inode); 153d68772b7SMatt Fleming dput(dentry); 154d68772b7SMatt Fleming return 0; 155d68772b7SMatt Fleming }; 156d68772b7SMatt Fleming 157d68772b7SMatt Fleming /* 158d68772b7SMatt Fleming * Handle negative dentry. 159d68772b7SMatt Fleming */ 160d68772b7SMatt Fleming static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry, 161d68772b7SMatt Fleming unsigned int flags) 162d68772b7SMatt Fleming { 163d68772b7SMatt Fleming if (dentry->d_name.len > NAME_MAX) 164d68772b7SMatt Fleming return ERR_PTR(-ENAMETOOLONG); 165d68772b7SMatt Fleming d_add(dentry, NULL); 166d68772b7SMatt Fleming return NULL; 167d68772b7SMatt Fleming } 168d68772b7SMatt Fleming 169d68772b7SMatt Fleming const struct inode_operations efivarfs_dir_inode_operations = { 170d68772b7SMatt Fleming .lookup = efivarfs_lookup, 171d68772b7SMatt Fleming .unlink = efivarfs_unlink, 172d68772b7SMatt Fleming .create = efivarfs_create, 173d68772b7SMatt Fleming }; 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