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, 18ed8b0de5SPeter Jones const struct inode *dir, int mode, 19ed8b0de5SPeter Jones dev_t dev, bool is_removable) 20d68772b7SMatt Fleming { 21d68772b7SMatt Fleming struct inode *inode = new_inode(sb); 22d68772b7SMatt Fleming 23d68772b7SMatt Fleming if (inode) { 24d68772b7SMatt Fleming inode->i_ino = get_next_ino(); 25d68772b7SMatt Fleming inode->i_mode = mode; 26d68772b7SMatt Fleming inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 27ed8b0de5SPeter Jones inode->i_flags = is_removable ? 0 : S_IMMUTABLE; 28d68772b7SMatt Fleming switch (mode & S_IFMT) { 29d68772b7SMatt Fleming case S_IFREG: 30d68772b7SMatt Fleming inode->i_fop = &efivarfs_file_operations; 31d68772b7SMatt Fleming break; 32d68772b7SMatt Fleming case S_IFDIR: 33d68772b7SMatt Fleming inode->i_op = &efivarfs_dir_inode_operations; 34d68772b7SMatt Fleming inode->i_fop = &simple_dir_operations; 35d68772b7SMatt Fleming inc_nlink(inode); 36d68772b7SMatt Fleming break; 37d68772b7SMatt Fleming } 38d68772b7SMatt Fleming } 39d68772b7SMatt Fleming return inode; 40d68772b7SMatt Fleming } 41d68772b7SMatt Fleming 42d68772b7SMatt Fleming /* 43d68772b7SMatt Fleming * Return true if 'str' is a valid efivarfs filename of the form, 44d68772b7SMatt Fleming * 45d68772b7SMatt Fleming * VariableName-12345678-1234-1234-1234-1234567891bc 46d68772b7SMatt Fleming */ 47d68772b7SMatt Fleming bool efivarfs_valid_name(const char *str, int len) 48d68772b7SMatt Fleming { 49d68772b7SMatt Fleming static const char dashes[EFI_VARIABLE_GUID_LEN] = { 50d68772b7SMatt Fleming [8] = 1, [13] = 1, [18] = 1, [23] = 1 51d68772b7SMatt Fleming }; 52d68772b7SMatt Fleming const char *s = str + len - EFI_VARIABLE_GUID_LEN; 53d68772b7SMatt Fleming int i; 54d68772b7SMatt Fleming 55d68772b7SMatt Fleming /* 56d68772b7SMatt Fleming * We need a GUID, plus at least one letter for the variable name, 57d68772b7SMatt Fleming * plus the '-' separator 58d68772b7SMatt Fleming */ 59d68772b7SMatt Fleming if (len < EFI_VARIABLE_GUID_LEN + 2) 60d68772b7SMatt Fleming return false; 61d68772b7SMatt Fleming 62d68772b7SMatt Fleming /* GUID must be preceded by a '-' */ 63d68772b7SMatt Fleming if (*(s - 1) != '-') 64d68772b7SMatt Fleming return false; 65d68772b7SMatt Fleming 66d68772b7SMatt Fleming /* 67d68772b7SMatt Fleming * Validate that 's' is of the correct format, e.g. 68d68772b7SMatt Fleming * 69d68772b7SMatt Fleming * 12345678-1234-1234-1234-123456789abc 70d68772b7SMatt Fleming */ 71d68772b7SMatt Fleming for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) { 72d68772b7SMatt Fleming if (dashes[i]) { 73d68772b7SMatt Fleming if (*s++ != '-') 74d68772b7SMatt Fleming return false; 75d68772b7SMatt Fleming } else { 76d68772b7SMatt Fleming if (!isxdigit(*s++)) 77d68772b7SMatt Fleming return false; 78d68772b7SMatt Fleming } 79d68772b7SMatt Fleming } 80d68772b7SMatt Fleming 81d68772b7SMatt Fleming return true; 82d68772b7SMatt Fleming } 83d68772b7SMatt Fleming 84d68772b7SMatt Fleming static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid) 85d68772b7SMatt Fleming { 86d68772b7SMatt Fleming guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]); 87d68772b7SMatt Fleming guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]); 88d68772b7SMatt Fleming guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]); 89d68772b7SMatt Fleming guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]); 90d68772b7SMatt Fleming guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]); 91d68772b7SMatt Fleming guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]); 92d68772b7SMatt Fleming guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]); 93d68772b7SMatt Fleming guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]); 94d68772b7SMatt Fleming guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]); 95d68772b7SMatt Fleming guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]); 96d68772b7SMatt Fleming guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]); 97d68772b7SMatt Fleming guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]); 98d68772b7SMatt Fleming guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]); 99d68772b7SMatt Fleming guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]); 100d68772b7SMatt Fleming guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]); 101d68772b7SMatt Fleming guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]); 102d68772b7SMatt Fleming } 103d68772b7SMatt Fleming 104d68772b7SMatt Fleming static int efivarfs_create(struct inode *dir, struct dentry *dentry, 105d68772b7SMatt Fleming umode_t mode, bool excl) 106d68772b7SMatt Fleming { 107ed8b0de5SPeter Jones struct inode *inode = NULL; 108d68772b7SMatt Fleming struct efivar_entry *var; 109d68772b7SMatt Fleming int namelen, i = 0, err = 0; 110ed8b0de5SPeter Jones bool is_removable = false; 111d68772b7SMatt Fleming 112d68772b7SMatt Fleming if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) 113d68772b7SMatt Fleming return -EINVAL; 114d68772b7SMatt Fleming 115d68772b7SMatt Fleming var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); 116ed8b0de5SPeter Jones if (!var) 117ed8b0de5SPeter Jones return -ENOMEM; 118d68772b7SMatt Fleming 119d68772b7SMatt Fleming /* length of the variable name itself: remove GUID and separator */ 120d68772b7SMatt Fleming namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; 121d68772b7SMatt Fleming 122d68772b7SMatt Fleming efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1, 123d68772b7SMatt Fleming &var->var.VendorGuid); 124d68772b7SMatt Fleming 125ed8b0de5SPeter Jones if (efivar_variable_is_removable(var->var.VendorGuid, 126ed8b0de5SPeter Jones dentry->d_name.name, namelen)) 127ed8b0de5SPeter Jones is_removable = true; 128ed8b0de5SPeter Jones 129ed8b0de5SPeter Jones inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable); 130ed8b0de5SPeter Jones if (!inode) { 131ed8b0de5SPeter Jones err = -ENOMEM; 132ed8b0de5SPeter Jones goto out; 133ed8b0de5SPeter Jones } 134ed8b0de5SPeter Jones 135d68772b7SMatt Fleming for (i = 0; i < namelen; i++) 136d68772b7SMatt Fleming var->var.VariableName[i] = dentry->d_name.name[i]; 137d68772b7SMatt Fleming 138d68772b7SMatt Fleming var->var.VariableName[i] = '\0'; 139d68772b7SMatt Fleming 140d68772b7SMatt Fleming inode->i_private = var; 141d68772b7SMatt Fleming 142d68772b7SMatt Fleming efivar_entry_add(var, &efivarfs_list); 143d68772b7SMatt Fleming d_instantiate(dentry, inode); 144d68772b7SMatt Fleming dget(dentry); 145d68772b7SMatt Fleming out: 146d68772b7SMatt Fleming if (err) { 147d68772b7SMatt Fleming kfree(var); 148ed8b0de5SPeter Jones if (inode) 149d68772b7SMatt Fleming iput(inode); 150d68772b7SMatt Fleming } 151d68772b7SMatt Fleming return err; 152d68772b7SMatt Fleming } 153d68772b7SMatt Fleming 154d68772b7SMatt Fleming static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) 155d68772b7SMatt Fleming { 1562b0143b5SDavid Howells struct efivar_entry *var = d_inode(dentry)->i_private; 157d68772b7SMatt Fleming 158d68772b7SMatt Fleming if (efivar_entry_delete(var)) 159d68772b7SMatt Fleming return -EINVAL; 160d68772b7SMatt Fleming 1612b0143b5SDavid Howells drop_nlink(d_inode(dentry)); 162d68772b7SMatt Fleming dput(dentry); 163d68772b7SMatt Fleming return 0; 164d68772b7SMatt Fleming }; 165d68772b7SMatt Fleming 166d68772b7SMatt Fleming const struct inode_operations efivarfs_dir_inode_operations = { 1676e8cd2cbSAl Viro .lookup = simple_lookup, 168d68772b7SMatt Fleming .unlink = efivarfs_unlink, 169d68772b7SMatt Fleming .create = efivarfs_create, 170d68772b7SMatt Fleming }; 171