// 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 <jeremy.kerr@canonical.com>
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*/
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#include <linux/efi.h>
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#include <linux/delay.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/mount.h>
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#include "internal.h"
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static ssize_t efivarfs_file_write(struct file *file,
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const char __user *userbuf, size_t count, loff_t *ppos)
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{
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struct efivar_entry *var = file->private_data;
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void *data;
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u32 attributes;
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struct inode *inode = file->f_mapping->host;
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unsigned long datasize = count - sizeof(attributes);
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ssize_t bytes;
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bool set = false;
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if (count < sizeof(attributes))
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return -EINVAL;
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if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
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return -EFAULT;
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if (attributes & ~(EFI_VARIABLE_MASK))
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return -EINVAL;
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data = memdup_user(userbuf + sizeof(attributes), datasize);
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if (IS_ERR(data))
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return PTR_ERR(data);
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bytes = efivar_entry_set_get_size(var, attributes, &datasize,
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data, &set);
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if (!set && bytes) {
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if (bytes == -ENOENT)
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bytes = -EIO;
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goto out;
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}
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if (bytes == -ENOENT) {
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drop_nlink(inode);
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d_delete(file->f_path.dentry);
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dput(file->f_path.dentry);
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} else {
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inode_lock(inode);
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i_size_write(inode, datasize + sizeof(attributes));
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inode->i_mtime = current_time(inode);
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inode_unlock(inode);
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}
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bytes = count;
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out:
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kfree(data);
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return bytes;
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}
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static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
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size_t count, loff_t *ppos)
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{
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struct efivar_entry *var = file->private_data;
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unsigned long datasize = 0;
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u32 attributes;
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void *data;
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ssize_t size = 0;
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int err;
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while (!__ratelimit(&file->f_cred->user->ratelimit))
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msleep(50);
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err = efivar_entry_size(var, &datasize);
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/*
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* efivarfs represents uncommitted variables with
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* zero-length files. Reading them should return EOF.
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*/
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if (err == -ENOENT)
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return 0;
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else if (err)
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return err;
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data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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size = efivar_entry_get(var, &attributes, &datasize,
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data + sizeof(attributes));
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if (size)
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goto out_free;
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memcpy(data, &attributes, sizeof(attributes));
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size = simple_read_from_buffer(userbuf, count, ppos,
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data, datasize + sizeof(attributes));
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out_free:
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kfree(data);
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return size;
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}
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static inline unsigned int efivarfs_getflags(struct inode *inode)
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{
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unsigned int i_flags;
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unsigned int flags = 0;
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i_flags = inode->i_flags;
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if (i_flags & S_IMMUTABLE)
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flags |= FS_IMMUTABLE_FL;
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return flags;
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}
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static int
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efivarfs_ioc_getxflags(struct file *file, void __user *arg)
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{
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struct inode *inode = file->f_mapping->host;
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unsigned int flags = efivarfs_getflags(inode);
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if (copy_to_user(arg, &flags, sizeof(flags)))
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return -EFAULT;
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return 0;
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}
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static int
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efivarfs_ioc_setxflags(struct file *file, void __user *arg)
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{
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struct inode *inode = file->f_mapping->host;
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unsigned int flags;
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unsigned int i_flags = 0;
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unsigned int oldflags = efivarfs_getflags(inode);
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int error;
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if (!inode_owner_or_capable(inode))
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return -EACCES;
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if (copy_from_user(&flags, arg, sizeof(flags)))
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return -EFAULT;
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if (flags & ~FS_IMMUTABLE_FL)
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return -EOPNOTSUPP;
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if (flags & FS_IMMUTABLE_FL)
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i_flags |= S_IMMUTABLE;
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error = mnt_want_write_file(file);
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if (error)
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return error;
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inode_lock(inode);
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error = vfs_ioc_setflags_prepare(inode, oldflags, flags);
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if (error)
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goto out;
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inode_set_flags(inode, i_flags, S_IMMUTABLE);
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out:
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inode_unlock(inode);
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mnt_drop_write_file(file);
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return error;
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}
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static long
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efivarfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long p)
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{
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void __user *arg = (void __user *)p;
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switch (cmd) {
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case FS_IOC_GETFLAGS:
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return efivarfs_ioc_getxflags(file, arg);
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case FS_IOC_SETFLAGS:
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return efivarfs_ioc_setxflags(file, arg);
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}
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return -ENOTTY;
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}
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const struct file_operations efivarfs_file_operations = {
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.open = simple_open,
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.read = efivarfs_file_read,
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.write = efivarfs_file_write,
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.llseek = no_llseek,
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.unlocked_ioctl = efivarfs_file_ioctl,
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};
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