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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2012 Red Hat, Inc.
* Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
*/
#include <linux/efi.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include "internal.h"
static ssize_t efivarfs_file_write(struct file *file,
const char __user *userbuf, size_t count, loff_t *ppos)
{
struct efivar_entry *var = file->private_data;
void *data;
u32 attributes;
struct inode *inode = file->f_mapping->host;
unsigned long datasize = count - sizeof(attributes);
ssize_t bytes;
bool set = false;
if (count < sizeof(attributes))
return -EINVAL;
if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
return -EFAULT;
if (attributes & ~(EFI_VARIABLE_MASK))
return -EINVAL;
data = memdup_user(userbuf + sizeof(attributes), datasize);
if (IS_ERR(data))
return PTR_ERR(data);
bytes = efivar_entry_set_get_size(var, attributes, &datasize,
data, &set);
if (!set && bytes) {
if (bytes == -ENOENT)
bytes = -EIO;
goto out;
}
if (bytes == -ENOENT) {
drop_nlink(inode);
d_delete(file->f_path.dentry);
dput(file->f_path.dentry);
} else {
inode_lock(inode);
i_size_write(inode, datasize + sizeof(attributes));
inode->i_mtime = current_time(inode);
inode_unlock(inode);
}
bytes = count;
out:
kfree(data);
return bytes;
}
static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct efivar_entry *var = file->private_data;
unsigned long datasize = 0;
u32 attributes;
void *data;
ssize_t size = 0;
int err;
while (!__ratelimit(&file->f_cred->user->ratelimit))
msleep(50);
err = efivar_entry_size(var, &datasize);
/*
* efivarfs represents uncommitted variables with
* zero-length files. Reading them should return EOF.
*/
if (err == -ENOENT)
return 0;
else if (err)
return err;
data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
if (!data)
return -ENOMEM;
size = efivar_entry_get(var, &attributes, &datasize,
data + sizeof(attributes));
if (size)
goto out_free;
memcpy(data, &attributes, sizeof(attributes));
size = simple_read_from_buffer(userbuf, count, ppos,
data, datasize + sizeof(attributes));
out_free:
kfree(data);
return size;
}
static inline unsigned int efivarfs_getflags(struct inode *inode)
{
unsigned int i_flags;
unsigned int flags = 0;
i_flags = inode->i_flags;
if (i_flags & S_IMMUTABLE)
flags |= FS_IMMUTABLE_FL;
return flags;
}
static int
efivarfs_ioc_getxflags(struct file *file, void __user *arg)
{
struct inode *inode = file->f_mapping->host;
unsigned int flags = efivarfs_getflags(inode);
if (copy_to_user(arg, &flags, sizeof(flags)))
return -EFAULT;
return 0;
}
static int
efivarfs_ioc_setxflags(struct file *file, void __user *arg)
{
struct inode *inode = file->f_mapping->host;
unsigned int flags;
unsigned int i_flags = 0;
unsigned int oldflags = efivarfs_getflags(inode);
int error;
if (!inode_owner_or_capable(&init_user_ns, inode))
return -EACCES;
if (copy_from_user(&flags, arg, sizeof(flags)))
return -EFAULT;
if (flags & ~FS_IMMUTABLE_FL)
return -EOPNOTSUPP;
if (flags & FS_IMMUTABLE_FL)
i_flags |= S_IMMUTABLE;
error = mnt_want_write_file(file);
if (error)
return error;
inode_lock(inode);
error = vfs_ioc_setflags_prepare(inode, oldflags, flags);
if (error)
goto out;
inode_set_flags(inode, i_flags, S_IMMUTABLE);
out:
inode_unlock(inode);
mnt_drop_write_file(file);
return error;
}
static long
efivarfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long p)
{
void __user *arg = (void __user *)p;
switch (cmd) {
case FS_IOC_GETFLAGS:
return efivarfs_ioc_getxflags(file, arg);
case FS_IOC_SETFLAGS:
return efivarfs_ioc_setxflags(file, arg);
}
return -ENOTTY;
}
const struct file_operations efivarfs_file_operations = {
.open = simple_open,
.read = efivarfs_file_read,
.write = efivarfs_file_write,
.llseek = no_llseek,
.unlocked_ioctl = efivarfs_file_ioctl,
};
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