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191 lines
4.0 KiB
191 lines
4.0 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/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(&init_user_ns, 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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