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> 148236431dSAndy Shevchenko #include <linux/uuid.h> 15d68772b7SMatt Fleming 16d68772b7SMatt Fleming #include "internal.h" 17d68772b7SMatt Fleming 18d68772b7SMatt Fleming struct inode *efivarfs_get_inode(struct super_block *sb, 19ed8b0de5SPeter Jones const struct inode *dir, int mode, 20ed8b0de5SPeter Jones dev_t dev, bool is_removable) 21d68772b7SMatt Fleming { 22d68772b7SMatt Fleming struct inode *inode = new_inode(sb); 23d68772b7SMatt Fleming 24d68772b7SMatt Fleming if (inode) { 25d68772b7SMatt Fleming inode->i_ino = get_next_ino(); 26d68772b7SMatt Fleming inode->i_mode = mode; 27078cd827SDeepa Dinamani inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); 28ed8b0de5SPeter Jones inode->i_flags = is_removable ? 0 : S_IMMUTABLE; 29d68772b7SMatt Fleming switch (mode & S_IFMT) { 30d68772b7SMatt Fleming case S_IFREG: 31d68772b7SMatt Fleming inode->i_fop = &efivarfs_file_operations; 32d68772b7SMatt Fleming break; 33d68772b7SMatt Fleming case S_IFDIR: 34d68772b7SMatt Fleming inode->i_op = &efivarfs_dir_inode_operations; 35d68772b7SMatt Fleming inode->i_fop = &simple_dir_operations; 36d68772b7SMatt Fleming inc_nlink(inode); 37d68772b7SMatt Fleming break; 38d68772b7SMatt Fleming } 39d68772b7SMatt Fleming } 40d68772b7SMatt Fleming return inode; 41d68772b7SMatt Fleming } 42d68772b7SMatt Fleming 43d68772b7SMatt Fleming /* 44d68772b7SMatt Fleming * Return true if 'str' is a valid efivarfs filename of the form, 45d68772b7SMatt Fleming * 46d68772b7SMatt Fleming * VariableName-12345678-1234-1234-1234-1234567891bc 47d68772b7SMatt Fleming */ 48d68772b7SMatt Fleming bool efivarfs_valid_name(const char *str, int len) 49d68772b7SMatt Fleming { 50d68772b7SMatt Fleming const char *s = str + len - EFI_VARIABLE_GUID_LEN; 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 */ 688236431dSAndy Shevchenko return uuid_is_valid(s); 69d68772b7SMatt Fleming } 70d68772b7SMatt Fleming 71d68772b7SMatt Fleming static int efivarfs_create(struct inode *dir, struct dentry *dentry, 72d68772b7SMatt Fleming umode_t mode, bool excl) 73d68772b7SMatt Fleming { 74ed8b0de5SPeter Jones struct inode *inode = NULL; 75d68772b7SMatt Fleming struct efivar_entry *var; 76d68772b7SMatt Fleming int namelen, i = 0, err = 0; 77ed8b0de5SPeter Jones bool is_removable = false; 78d68772b7SMatt Fleming 79d68772b7SMatt Fleming if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) 80d68772b7SMatt Fleming return -EINVAL; 81d68772b7SMatt Fleming 82d68772b7SMatt Fleming var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); 83ed8b0de5SPeter Jones if (!var) 84ed8b0de5SPeter Jones return -ENOMEM; 85d68772b7SMatt Fleming 86d68772b7SMatt Fleming /* length of the variable name itself: remove GUID and separator */ 87d68772b7SMatt Fleming namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; 88d68772b7SMatt Fleming 89c4326563SAndy Shevchenko err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid); 90c4326563SAndy Shevchenko if (err) 91c4326563SAndy Shevchenko goto out; 92d68772b7SMatt Fleming 93ed8b0de5SPeter Jones if (efivar_variable_is_removable(var->var.VendorGuid, 94ed8b0de5SPeter Jones dentry->d_name.name, namelen)) 95ed8b0de5SPeter Jones is_removable = true; 96ed8b0de5SPeter Jones 97ed8b0de5SPeter Jones inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable); 98ed8b0de5SPeter Jones if (!inode) { 99ed8b0de5SPeter Jones err = -ENOMEM; 100ed8b0de5SPeter Jones goto out; 101ed8b0de5SPeter Jones } 102ed8b0de5SPeter Jones 103d68772b7SMatt Fleming for (i = 0; i < namelen; i++) 104d68772b7SMatt Fleming var->var.VariableName[i] = dentry->d_name.name[i]; 105d68772b7SMatt Fleming 106d68772b7SMatt Fleming var->var.VariableName[i] = '\0'; 107d68772b7SMatt Fleming 108d68772b7SMatt Fleming inode->i_private = var; 109d68772b7SMatt Fleming 11021b3ddd3SSylvain Chouleur err = efivar_entry_add(var, &efivarfs_list); 11121b3ddd3SSylvain Chouleur if (err) 11221b3ddd3SSylvain Chouleur goto out; 11321b3ddd3SSylvain Chouleur 114d68772b7SMatt Fleming d_instantiate(dentry, inode); 115d68772b7SMatt Fleming dget(dentry); 116d68772b7SMatt Fleming out: 117d68772b7SMatt Fleming if (err) { 118d68772b7SMatt Fleming kfree(var); 119ed8b0de5SPeter Jones if (inode) 120d68772b7SMatt Fleming iput(inode); 121d68772b7SMatt Fleming } 122d68772b7SMatt Fleming return err; 123d68772b7SMatt Fleming } 124d68772b7SMatt Fleming 125d68772b7SMatt Fleming static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) 126d68772b7SMatt Fleming { 1272b0143b5SDavid Howells struct efivar_entry *var = d_inode(dentry)->i_private; 128d68772b7SMatt Fleming 129d68772b7SMatt Fleming if (efivar_entry_delete(var)) 130d68772b7SMatt Fleming return -EINVAL; 131d68772b7SMatt Fleming 1322b0143b5SDavid Howells drop_nlink(d_inode(dentry)); 133d68772b7SMatt Fleming dput(dentry); 134d68772b7SMatt Fleming return 0; 135d68772b7SMatt Fleming }; 136d68772b7SMatt Fleming 137d68772b7SMatt Fleming const struct inode_operations efivarfs_dir_inode_operations = { 1386e8cd2cbSAl Viro .lookup = simple_lookup, 139d68772b7SMatt Fleming .unlink = efivarfs_unlink, 140d68772b7SMatt Fleming .create = efivarfs_create, 141d68772b7SMatt Fleming }; 142