/* * Copyright (C) 2012 Red Hat, Inc. * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/efi.h> #include <linux/fs.h> #include <linux/ctype.h> #include <linux/slab.h> #include <linux/uuid.h> #include "internal.h" struct inode *efivarfs_get_inode(struct super_block *sb, const struct inode *dir, int mode, dev_t dev, bool is_removable) { struct inode *inode = new_inode(sb); if (inode) { inode->i_ino = get_next_ino(); inode->i_mode = mode; inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); inode->i_flags = is_removable ? 0 : S_IMMUTABLE; switch (mode & S_IFMT) { case S_IFREG: inode->i_fop = &efivarfs_file_operations; break; case S_IFDIR: inode->i_op = &efivarfs_dir_inode_operations; inode->i_fop = &simple_dir_operations; inc_nlink(inode); break; } } return inode; } /* * Return true if 'str' is a valid efivarfs filename of the form, * * VariableName-12345678-1234-1234-1234-1234567891bc */ bool efivarfs_valid_name(const char *str, int len) { const char *s = str + len - EFI_VARIABLE_GUID_LEN; /* * We need a GUID, plus at least one letter for the variable name, * plus the '-' separator */ if (len < EFI_VARIABLE_GUID_LEN + 2) return false; /* GUID must be preceded by a '-' */ if (*(s - 1) != '-') return false; /* * Validate that 's' is of the correct format, e.g. * * 12345678-1234-1234-1234-123456789abc */ return uuid_is_valid(s); } static int efivarfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { struct inode *inode = NULL; struct efivar_entry *var; int namelen, i = 0, err = 0; bool is_removable = false; if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) return -EINVAL; var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); if (!var) return -ENOMEM; /* length of the variable name itself: remove GUID and separator */ namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid); if (err) goto out; if (efivar_variable_is_removable(var->var.VendorGuid, dentry->d_name.name, namelen)) is_removable = true; inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable); if (!inode) { err = -ENOMEM; goto out; } for (i = 0; i < namelen; i++) var->var.VariableName[i] = dentry->d_name.name[i]; var->var.VariableName[i] = '\0'; inode->i_private = var; err = efivar_entry_add(var, &efivarfs_list); if (err) goto out; d_instantiate(dentry, inode); dget(dentry); out: if (err) { kfree(var); if (inode) iput(inode); } return err; } static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) { struct efivar_entry *var = d_inode(dentry)->i_private; if (efivar_entry_delete(var)) return -EINVAL; drop_nlink(d_inode(dentry)); dput(dentry); return 0; }; const struct inode_operations efivarfs_dir_inode_operations = { .lookup = simple_lookup, .unlink = efivarfs_unlink, .create = efivarfs_create, };