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140 lines
3.1 KiB
140 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2012 Red Hat, Inc. |
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* Copyright (C) 2012 Jeremy Kerr <[email protected]> |
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*/ |
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#include <linux/efi.h> |
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#include <linux/fs.h> |
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#include <linux/ctype.h> |
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#include <linux/kmemleak.h> |
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#include <linux/slab.h> |
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#include <linux/uuid.h> |
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#include "internal.h" |
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struct inode *efivarfs_get_inode(struct super_block *sb, |
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const struct inode *dir, int mode, |
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dev_t dev, bool is_removable) |
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{ |
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struct inode *inode = new_inode(sb); |
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if (inode) { |
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inode->i_ino = get_next_ino(); |
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inode->i_mode = mode; |
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inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
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inode->i_flags = is_removable ? 0 : S_IMMUTABLE; |
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switch (mode & S_IFMT) { |
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case S_IFREG: |
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inode->i_fop = &efivarfs_file_operations; |
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break; |
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case S_IFDIR: |
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inode->i_op = &efivarfs_dir_inode_operations; |
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inode->i_fop = &simple_dir_operations; |
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inc_nlink(inode); |
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break; |
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} |
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} |
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return inode; |
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} |
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/* |
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* Return true if 'str' is a valid efivarfs filename of the form, |
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* |
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* VariableName-12345678-1234-1234-1234-1234567891bc |
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*/ |
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bool efivarfs_valid_name(const char *str, int len) |
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{ |
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const char *s = str + len - EFI_VARIABLE_GUID_LEN; |
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/* |
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* We need a GUID, plus at least one letter for the variable name, |
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* plus the '-' separator |
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*/ |
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if (len < EFI_VARIABLE_GUID_LEN + 2) |
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return false; |
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/* GUID must be preceded by a '-' */ |
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if (*(s - 1) != '-') |
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return false; |
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/* |
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* Validate that 's' is of the correct format, e.g. |
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* |
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* 12345678-1234-1234-1234-123456789abc |
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*/ |
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return uuid_is_valid(s); |
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} |
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static int efivarfs_create(struct user_namespace *mnt_userns, struct inode *dir, |
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struct dentry *dentry, umode_t mode, bool excl) |
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{ |
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struct inode *inode = NULL; |
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struct efivar_entry *var; |
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int namelen, i = 0, err = 0; |
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bool is_removable = false; |
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if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) |
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return -EINVAL; |
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var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); |
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if (!var) |
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return -ENOMEM; |
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/* length of the variable name itself: remove GUID and separator */ |
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namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; |
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err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid); |
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if (err) |
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goto out; |
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if (efivar_variable_is_removable(var->var.VendorGuid, |
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dentry->d_name.name, namelen)) |
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is_removable = true; |
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inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable); |
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if (!inode) { |
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err = -ENOMEM; |
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goto out; |
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} |
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for (i = 0; i < namelen; i++) |
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var->var.VariableName[i] = dentry->d_name.name[i]; |
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var->var.VariableName[i] = '\0'; |
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inode->i_private = var; |
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kmemleak_ignore(var); |
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err = efivar_entry_add(var, &efivarfs_list); |
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if (err) |
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goto out; |
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d_instantiate(dentry, inode); |
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dget(dentry); |
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out: |
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if (err) { |
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kfree(var); |
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if (inode) |
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iput(inode); |
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} |
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return err; |
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} |
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static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) |
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{ |
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struct efivar_entry *var = d_inode(dentry)->i_private; |
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if (efivar_entry_delete(var)) |
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return -EINVAL; |
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drop_nlink(d_inode(dentry)); |
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dput(dentry); |
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return 0; |
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}; |
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const struct inode_operations efivarfs_dir_inode_operations = { |
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.lookup = simple_lookup, |
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.unlink = efivarfs_unlink, |
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.create = efivarfs_create, |
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};
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