1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2d68772b7SMatt Fleming /* 3d68772b7SMatt Fleming * Copyright (C) 2012 Red Hat, Inc. 4d68772b7SMatt Fleming * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> 5d68772b7SMatt Fleming */ 6d68772b7SMatt Fleming 7d68772b7SMatt Fleming #include <linux/efi.h> 8d68772b7SMatt Fleming #include <linux/fs.h> 9d68772b7SMatt Fleming #include <linux/ctype.h> 10ff04f3b6SArd Biesheuvel #include <linux/kmemleak.h> 1120b4fb48SLinus Torvalds #include <linux/slab.h> 128236431dSAndy Shevchenko #include <linux/uuid.h> 13d68772b7SMatt Fleming 14d68772b7SMatt Fleming #include "internal.h" 15d68772b7SMatt Fleming 16d68772b7SMatt Fleming struct inode *efivarfs_get_inode(struct super_block *sb, 17ed8b0de5SPeter Jones const struct inode *dir, int mode, 18ed8b0de5SPeter Jones dev_t dev, bool is_removable) 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; 25078cd827SDeepa Dinamani inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); 26ed8b0de5SPeter Jones inode->i_flags = is_removable ? 0 : S_IMMUTABLE; 27d68772b7SMatt Fleming switch (mode & S_IFMT) { 28d68772b7SMatt Fleming case S_IFREG: 29d68772b7SMatt Fleming inode->i_fop = &efivarfs_file_operations; 30d68772b7SMatt Fleming break; 31d68772b7SMatt Fleming case S_IFDIR: 32d68772b7SMatt Fleming inode->i_op = &efivarfs_dir_inode_operations; 33d68772b7SMatt Fleming inode->i_fop = &simple_dir_operations; 34d68772b7SMatt Fleming inc_nlink(inode); 35d68772b7SMatt Fleming break; 36d68772b7SMatt Fleming } 37d68772b7SMatt Fleming } 38d68772b7SMatt Fleming return inode; 39d68772b7SMatt Fleming } 40d68772b7SMatt Fleming 41d68772b7SMatt Fleming /* 42d68772b7SMatt Fleming * Return true if 'str' is a valid efivarfs filename of the form, 43d68772b7SMatt Fleming * 44d68772b7SMatt Fleming * VariableName-12345678-1234-1234-1234-1234567891bc 45d68772b7SMatt Fleming */ 46d68772b7SMatt Fleming bool efivarfs_valid_name(const char *str, int len) 47d68772b7SMatt Fleming { 48d68772b7SMatt Fleming const char *s = str + len - EFI_VARIABLE_GUID_LEN; 49d68772b7SMatt Fleming 50d68772b7SMatt Fleming /* 51d68772b7SMatt Fleming * We need a GUID, plus at least one letter for the variable name, 52d68772b7SMatt Fleming * plus the '-' separator 53d68772b7SMatt Fleming */ 54d68772b7SMatt Fleming if (len < EFI_VARIABLE_GUID_LEN + 2) 55d68772b7SMatt Fleming return false; 56d68772b7SMatt Fleming 57d68772b7SMatt Fleming /* GUID must be preceded by a '-' */ 58d68772b7SMatt Fleming if (*(s - 1) != '-') 59d68772b7SMatt Fleming return false; 60d68772b7SMatt Fleming 61d68772b7SMatt Fleming /* 62d68772b7SMatt Fleming * Validate that 's' is of the correct format, e.g. 63d68772b7SMatt Fleming * 64d68772b7SMatt Fleming * 12345678-1234-1234-1234-123456789abc 65d68772b7SMatt Fleming */ 668236431dSAndy Shevchenko return uuid_is_valid(s); 67d68772b7SMatt Fleming } 68d68772b7SMatt Fleming 69*549c7297SChristian Brauner static int efivarfs_create(struct user_namespace *mnt_userns, struct inode *dir, 70*549c7297SChristian Brauner struct dentry *dentry, umode_t mode, bool excl) 71d68772b7SMatt Fleming { 72ed8b0de5SPeter Jones struct inode *inode = NULL; 73d68772b7SMatt Fleming struct efivar_entry *var; 74d68772b7SMatt Fleming int namelen, i = 0, err = 0; 75ed8b0de5SPeter Jones bool is_removable = false; 76d68772b7SMatt Fleming 77d68772b7SMatt Fleming if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) 78d68772b7SMatt Fleming return -EINVAL; 79d68772b7SMatt Fleming 80d68772b7SMatt Fleming var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); 81ed8b0de5SPeter Jones if (!var) 82ed8b0de5SPeter Jones return -ENOMEM; 83d68772b7SMatt Fleming 84d68772b7SMatt Fleming /* length of the variable name itself: remove GUID and separator */ 85d68772b7SMatt Fleming namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; 86d68772b7SMatt Fleming 87c4326563SAndy Shevchenko err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid); 88c4326563SAndy Shevchenko if (err) 89c4326563SAndy Shevchenko goto out; 90d68772b7SMatt Fleming 91ed8b0de5SPeter Jones if (efivar_variable_is_removable(var->var.VendorGuid, 92ed8b0de5SPeter Jones dentry->d_name.name, namelen)) 93ed8b0de5SPeter Jones is_removable = true; 94ed8b0de5SPeter Jones 95ed8b0de5SPeter Jones inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable); 96ed8b0de5SPeter Jones if (!inode) { 97ed8b0de5SPeter Jones err = -ENOMEM; 98ed8b0de5SPeter Jones goto out; 99ed8b0de5SPeter Jones } 100ed8b0de5SPeter Jones 101d68772b7SMatt Fleming for (i = 0; i < namelen; i++) 102d68772b7SMatt Fleming var->var.VariableName[i] = dentry->d_name.name[i]; 103d68772b7SMatt Fleming 104d68772b7SMatt Fleming var->var.VariableName[i] = '\0'; 105d68772b7SMatt Fleming 106d68772b7SMatt Fleming inode->i_private = var; 107ff04f3b6SArd Biesheuvel kmemleak_ignore(var); 108d68772b7SMatt Fleming 10921b3ddd3SSylvain Chouleur err = efivar_entry_add(var, &efivarfs_list); 11021b3ddd3SSylvain Chouleur if (err) 11121b3ddd3SSylvain Chouleur goto out; 11221b3ddd3SSylvain Chouleur 113d68772b7SMatt Fleming d_instantiate(dentry, inode); 114d68772b7SMatt Fleming dget(dentry); 115d68772b7SMatt Fleming out: 116d68772b7SMatt Fleming if (err) { 117d68772b7SMatt Fleming kfree(var); 118ed8b0de5SPeter Jones if (inode) 119d68772b7SMatt Fleming iput(inode); 120d68772b7SMatt Fleming } 121d68772b7SMatt Fleming return err; 122d68772b7SMatt Fleming } 123d68772b7SMatt Fleming 124d68772b7SMatt Fleming static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) 125d68772b7SMatt Fleming { 1262b0143b5SDavid Howells struct efivar_entry *var = d_inode(dentry)->i_private; 127d68772b7SMatt Fleming 128d68772b7SMatt Fleming if (efivar_entry_delete(var)) 129d68772b7SMatt Fleming return -EINVAL; 130d68772b7SMatt Fleming 1312b0143b5SDavid Howells drop_nlink(d_inode(dentry)); 132d68772b7SMatt Fleming dput(dentry); 133d68772b7SMatt Fleming return 0; 134d68772b7SMatt Fleming }; 135d68772b7SMatt Fleming 136d68772b7SMatt Fleming const struct inode_operations efivarfs_dir_inode_operations = { 1376e8cd2cbSAl Viro .lookup = simple_lookup, 138d68772b7SMatt Fleming .unlink = efivarfs_unlink, 139d68772b7SMatt Fleming .create = efivarfs_create, 140d68772b7SMatt Fleming }; 141