[mirror_ubuntu-jammy-kernel.git] / fs / efivarfs / inode.c

// 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/fs.h>
#include <linux/ctype.h>
#include <linux/kmemleak.h>
#include <linux/slab.h>
#include <linux/uuid.h>
#include <linux/fileattr.h>

#include "internal.h"

static const struct inode_operations efivarfs_file_inode_operations;

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_op = &efivarfs_file_inode_operations;
			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 user_namespace *mnt_userns, 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;
	kmemleak_ignore(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,
};

static int
efivarfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
{
	unsigned int i_flags;
	unsigned int flags = 0;

	i_flags = d_inode(dentry)->i_flags;
	if (i_flags & S_IMMUTABLE)
		flags |= FS_IMMUTABLE_FL;

	fileattr_fill_flags(fa, flags);

	return 0;
}

static int
efivarfs_fileattr_set(struct user_namespace *mnt_userns,
		      struct dentry *dentry, struct fileattr *fa)
{
	unsigned int i_flags = 0;

	if (fileattr_has_fsx(fa))
		return -EOPNOTSUPP;

	if (fa->flags & ~FS_IMMUTABLE_FL)
		return -EOPNOTSUPP;

	if (fa->flags & FS_IMMUTABLE_FL)
		i_flags |= S_IMMUTABLE;

	inode_set_flags(d_inode(dentry), i_flags, S_IMMUTABLE);

	return 0;
}

static const struct inode_operations efivarfs_file_inode_operations = {
	.fileattr_get = efivarfs_fileattr_get,
	.fileattr_set = efivarfs_fileattr_set,
};
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
d68772b7 MF	2	/*
	3	* Copyright (C) 2012 Red Hat, Inc.
	4	* Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
d68772b7 MF	5	*/
	6
	7	#include <linux/efi.h>
	8	#include <linux/fs.h>
	9	#include <linux/ctype.h>
ff04f3b6	10	#include <linux/kmemleak.h>
20b4fb48	11	#include <linux/slab.h>
8236431d	12	#include <linux/uuid.h>
d701ea28	13	#include <linux/fileattr.h>
d68772b7 MF	14
	15	#include "internal.h"
	16
d701ea28 MS	17	static const struct inode_operations efivarfs_file_inode_operations;
d701ea28 MS	18
d68772b7	19	struct inode efivarfs_get_inode(struct super_block sb,
ed8b0de5 PJ	20	const struct inode *dir, int mode,
ed8b0de5 PJ	21	dev_t dev, bool is_removable)
d68772b7 MF	22	{
	23	struct inode *inode = new_inode(sb);
	24
	25	if (inode) {
	26	inode->i_ino = get_next_ino();
	27	inode->i_mode = mode;
078cd827	28	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
ed8b0de5	29	inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
d68772b7 MF	30	switch (mode & S_IFMT) {
d68772b7 MF	31	case S_IFREG:
d701ea28	32	inode->i_op = &efivarfs_file_inode_operations;
d68772b7 MF	33	inode->i_fop = &efivarfs_file_operations;
	34	break;
	35	case S_IFDIR:
	36	inode->i_op = &efivarfs_dir_inode_operations;
	37	inode->i_fop = &simple_dir_operations;
	38	inc_nlink(inode);
	39	break;
	40	}
	41	}
	42	return inode;
	43	}
	44
	45	/*
	46	* Return true if 'str' is a valid efivarfs filename of the form,
	47	*
	48	* VariableName-12345678-1234-1234-1234-1234567891bc
	49	*/
	50	bool efivarfs_valid_name(const char *str, int len)
	51	{
d68772b7	52	const char *s = str + len - EFI_VARIABLE_GUID_LEN;
d68772b7 MF	53
	54	/*
	55	* We need a GUID, plus at least one letter for the variable name,
	56	* plus the '-' separator
	57	*/
	58	if (len < EFI_VARIABLE_GUID_LEN + 2)
	59	return false;
	60
	61	/* GUID must be preceded by a '-' */
	62	if (*(s - 1) != '-')
	63	return false;
	64
	65	/*
	66	* Validate that 's' is of the correct format, e.g.
	67	*
	68	* 12345678-1234-1234-1234-123456789abc
	69	*/
8236431d	70	return uuid_is_valid(s);
d68772b7 MF	71	}
d68772b7 MF	72
549c7297 CB	73	static int efivarfs_create(struct user_namespace mnt_userns, struct inode dir,
549c7297 CB	74	struct dentry *dentry, umode_t mode, bool excl)
d68772b7	75	{
ed8b0de5	76	struct inode *inode = NULL;
d68772b7 MF	77	struct efivar_entry *var;
d68772b7 MF	78	int namelen, i = 0, err = 0;
ed8b0de5	79	bool is_removable = false;
d68772b7 MF	80
	81	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
	82	return -EINVAL;
	83
d68772b7	84	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
ed8b0de5 PJ	85	if (!var)
ed8b0de5 PJ	86	return -ENOMEM;
d68772b7 MF	87
	88	/* length of the variable name itself: remove GUID and separator */
	89	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
	90
c4326563 AS	91	err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
	92	if (err)
	93	goto out;
d68772b7	94
ed8b0de5 PJ	95	if (efivar_variable_is_removable(var->var.VendorGuid,
	96	dentry->d_name.name, namelen))
	97	is_removable = true;
	98
	99	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
	100	if (!inode) {
	101	err = -ENOMEM;
	102	goto out;
	103	}
	104
d68772b7 MF	105	for (i = 0; i < namelen; i++)
	106	var->var.VariableName[i] = dentry->d_name.name[i];
	107
	108	var->var.VariableName[i] = '\0';
	109
	110	inode->i_private = var;
ff04f3b6	111	kmemleak_ignore(var);
d68772b7	112
21b3ddd3 SC	113	err = efivar_entry_add(var, &efivarfs_list);
	114	if (err)
	115	goto out;
	116
d68772b7 MF	117	d_instantiate(dentry, inode);
	118	dget(dentry);
	119	out:
	120	if (err) {
	121	kfree(var);
ed8b0de5 PJ	122	if (inode)
ed8b0de5 PJ	123	iput(inode);
d68772b7 MF	124	}
	125	return err;
	126	}
	127
	128	static int efivarfs_unlink(struct inode dir, struct dentry dentry)
	129	{
2b0143b5	130	struct efivar_entry *var = d_inode(dentry)->i_private;
d68772b7 MF	131
	132	if (efivar_entry_delete(var))
	133	return -EINVAL;
	134
2b0143b5	135	drop_nlink(d_inode(dentry));
d68772b7 MF	136	dput(dentry);
	137	return 0;
	138	};
	139
d68772b7	140	const struct inode_operations efivarfs_dir_inode_operations = {
6e8cd2cb	141	.lookup = simple_lookup,
d68772b7 MF	142	.unlink = efivarfs_unlink,
	143	.create = efivarfs_create,
	144	};
d701ea28 MS	145
	146	static int
	147	efivarfs_fileattr_get(struct dentry dentry, struct fileattr fa)
	148	{
	149	unsigned int i_flags;
	150	unsigned int flags = 0;
	151
	152	i_flags = d_inode(dentry)->i_flags;
	153	if (i_flags & S_IMMUTABLE)
	154	flags \|= FS_IMMUTABLE_FL;
	155
	156	fileattr_fill_flags(fa, flags);
	157
	158	return 0;
	159	}
	160
	161	static int
	162	efivarfs_fileattr_set(struct user_namespace *mnt_userns,
	163	struct dentry dentry, struct fileattr fa)
	164	{
	165	unsigned int i_flags = 0;
	166
	167	if (fileattr_has_fsx(fa))
	168	return -EOPNOTSUPP;
	169
	170	if (fa->flags & ~FS_IMMUTABLE_FL)
	171	return -EOPNOTSUPP;
	172
	173	if (fa->flags & FS_IMMUTABLE_FL)
	174	i_flags \|= S_IMMUTABLE;
	175
	176	inode_set_flags(d_inode(dentry), i_flags, S_IMMUTABLE);
	177
	178	return 0;
	179	}
	180
	181	static const struct inode_operations efivarfs_file_inode_operations = {
	182	.fileattr_get = efivarfs_fileattr_get,
	183	.fileattr_set = efivarfs_fileattr_set,
	184	};