[linux-2.6-block.git] / fs / efivarfs / super.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/ctype.h>
#include <linux/efi.h>
#include <linux/fs.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/ucs2_string.h>
#include <linux/slab.h>
#include <linux/magic.h>
#include <linux/statfs.h>
#include <linux/notifier.h>
#include <linux/printk.h>

#include "internal.h"

static int efivarfs_ops_notifier(struct notifier_block *nb, unsigned long event,
				 void *data)
{
	struct efivarfs_fs_info *sfi = container_of(nb, struct efivarfs_fs_info, nb);

	switch (event) {
	case EFIVAR_OPS_RDONLY:
		sfi->sb->s_flags |= SB_RDONLY;
		break;
	case EFIVAR_OPS_RDWR:
		sfi->sb->s_flags &= ~SB_RDONLY;
		break;
	default:
		return NOTIFY_DONE;
	}

	return NOTIFY_OK;
}

static void efivarfs_evict_inode(struct inode *inode)
{
	clear_inode(inode);
}

static int efivarfs_show_options(struct seq_file *m, struct dentry *root)
{
	struct super_block *sb = root->d_sb;
	struct efivarfs_fs_info *sbi = sb->s_fs_info;
	struct efivarfs_mount_opts *opts = &sbi->mount_opts;

	if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
		seq_printf(m, ",uid=%u",
				from_kuid_munged(&init_user_ns, opts->uid));
	if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
		seq_printf(m, ",gid=%u",
				from_kgid_munged(&init_user_ns, opts->gid));
	return 0;
}

static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	const u32 attr = EFI_VARIABLE_NON_VOLATILE |
			 EFI_VARIABLE_BOOTSERVICE_ACCESS |
			 EFI_VARIABLE_RUNTIME_ACCESS;
	u64 storage_space, remaining_space, max_variable_size;
	u64 id = huge_encode_dev(dentry->d_sb->s_dev);
	efi_status_t status;

	/* Some UEFI firmware does not implement QueryVariableInfo() */
	storage_space = remaining_space = 0;
	if (efi_rt_services_supported(EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO)) {
		status = efivar_query_variable_info(attr, &storage_space,
						    &remaining_space,
						    &max_variable_size);
		if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED)
			pr_warn_ratelimited("query_variable_info() failed: 0x%lx\n",
					    status);
	}

	/*
	 * This is not a normal filesystem, so no point in pretending it has a block
	 * size; we declare f_bsize to 1, so that we can then report the exact value
	 * sent by EFI QueryVariableInfo in f_blocks and f_bfree
	 */
	buf->f_bsize	= 1;
	buf->f_namelen	= NAME_MAX;
	buf->f_blocks	= storage_space;
	buf->f_bfree	= remaining_space;
	buf->f_type	= dentry->d_sb->s_magic;
	buf->f_fsid	= u64_to_fsid(id);

	/*
	 * In f_bavail we declare the free space that the kernel will allow writing
	 * when the storage_paranoia x86 quirk is active. To use more, users
	 * should boot the kernel with efi_no_storage_paranoia.
	 */
	if (remaining_space > efivar_reserved_space())
		buf->f_bavail = remaining_space - efivar_reserved_space();
	else
		buf->f_bavail = 0;

	return 0;
}
static const struct super_operations efivarfs_ops = {
	.statfs = efivarfs_statfs,
	.drop_inode = generic_delete_inode,
	.evict_inode = efivarfs_evict_inode,
	.show_options = efivarfs_show_options,
};

/*
 * Compare two efivarfs file names.
 *
 * An efivarfs filename is composed of two parts,
 *
 *	1. A case-sensitive variable name
 *	2. A case-insensitive GUID
 *
 * So we need to perform a case-sensitive match on part 1 and a
 * case-insensitive match on part 2.
 */
static int efivarfs_d_compare(const struct dentry *dentry,
			      unsigned int len, const char *str,
			      const struct qstr *name)
{
	int guid = len - EFI_VARIABLE_GUID_LEN;

	if (name->len != len)
		return 1;

	/* Case-sensitive compare for the variable name */
	if (memcmp(str, name->name, guid))
		return 1;

	/* Case-insensitive compare for the GUID */
	return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
}

static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr)
{
	unsigned long hash = init_name_hash(dentry);
	const unsigned char *s = qstr->name;
	unsigned int len = qstr->len;

	if (!efivarfs_valid_name(s, len))
		return -EINVAL;

	while (len-- > EFI_VARIABLE_GUID_LEN)
		hash = partial_name_hash(*s++, hash);

	/* GUID is case-insensitive. */
	while (len--)
		hash = partial_name_hash(tolower(*s++), hash);

	qstr->hash = end_name_hash(hash);
	return 0;
}

static const struct dentry_operations efivarfs_d_ops = {
	.d_compare = efivarfs_d_compare,
	.d_hash = efivarfs_d_hash,
	.d_delete = always_delete_dentry,
};

static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
{
	struct dentry *d;
	struct qstr q;
	int err;

	q.name = name;
	q.len = strlen(name);

	err = efivarfs_d_hash(parent, &q);
	if (err)
		return ERR_PTR(err);

	d = d_alloc(parent, &q);
	if (d)
		return d;

	return ERR_PTR(-ENOMEM);
}

static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
			     unsigned long name_size, void *data,
			     struct list_head *list)
{
	struct super_block *sb = (struct super_block *)data;
	struct efivar_entry *entry;
	struct inode *inode = NULL;
	struct dentry *dentry, *root = sb->s_root;
	unsigned long size = 0;
	char *name;
	int len;
	int err = -ENOMEM;
	bool is_removable = false;

	if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
		return 0;

	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return err;

	memcpy(entry->var.VariableName, name16, name_size);
	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));

	len = ucs2_utf8size(entry->var.VariableName);

	/* name, plus '-', plus GUID, plus NUL*/
	name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
	if (!name)
		goto fail;

	ucs2_as_utf8(name, entry->var.VariableName, len);

	if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
		is_removable = true;

	name[len] = '-';

	efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);

	name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';

	/* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
	strreplace(name, '/', '!');

	inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
				   is_removable);
	if (!inode)
		goto fail_name;

	dentry = efivarfs_alloc_dentry(root, name);
	if (IS_ERR(dentry)) {
		err = PTR_ERR(dentry);
		goto fail_inode;
	}

	__efivar_entry_get(entry, NULL, &size, NULL);
	__efivar_entry_add(entry, list);

	/* copied by the above to local storage in the dentry. */
	kfree(name);

	inode_lock(inode);
	inode->i_private = entry;
	i_size_write(inode, size + sizeof(entry->var.Attributes));
	inode_unlock(inode);
	d_add(dentry, inode);

	return 0;

fail_inode:
	iput(inode);
fail_name:
	kfree(name);
fail:
	kfree(entry);
	return err;
}

static int efivarfs_destroy(struct efivar_entry *entry, void *data)
{
	efivar_entry_remove(entry);
	kfree(entry);
	return 0;
}

enum {
	Opt_uid, Opt_gid,
};

static const struct fs_parameter_spec efivarfs_parameters[] = {
	fsparam_u32("uid", Opt_uid),
	fsparam_u32("gid", Opt_gid),
	{},
};

static int efivarfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
	struct efivarfs_fs_info *sbi = fc->s_fs_info;
	struct efivarfs_mount_opts *opts = &sbi->mount_opts;
	struct fs_parse_result result;
	int opt;

	opt = fs_parse(fc, efivarfs_parameters, param, &result);
	if (opt < 0)
		return opt;

	switch (opt) {
	case Opt_uid:
		opts->uid = make_kuid(current_user_ns(), result.uint_32);
		if (!uid_valid(opts->uid))
			return -EINVAL;
		break;
	case Opt_gid:
		opts->gid = make_kgid(current_user_ns(), result.uint_32);
		if (!gid_valid(opts->gid))
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
	struct efivarfs_fs_info *sfi = sb->s_fs_info;
	struct inode *inode = NULL;
	struct dentry *root;
	int err;

	sb->s_maxbytes          = MAX_LFS_FILESIZE;
	sb->s_blocksize         = PAGE_SIZE;
	sb->s_blocksize_bits    = PAGE_SHIFT;
	sb->s_magic             = EFIVARFS_MAGIC;
	sb->s_op                = &efivarfs_ops;
	sb->s_d_op		= &efivarfs_d_ops;
	sb->s_time_gran         = 1;

	if (!efivar_supports_writes())
		sb->s_flags |= SB_RDONLY;

	inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true);
	if (!inode)
		return -ENOMEM;
	inode->i_op = &efivarfs_dir_inode_operations;

	root = d_make_root(inode);
	sb->s_root = root;
	if (!root)
		return -ENOMEM;

	sfi->sb = sb;
	sfi->nb.notifier_call = efivarfs_ops_notifier;
	err = blocking_notifier_chain_register(&efivar_ops_nh, &sfi->nb);
	if (err)
		return err;

	return efivar_init(efivarfs_callback, sb, &sfi->efivarfs_list);
}

static int efivarfs_get_tree(struct fs_context *fc)
{
	return get_tree_single(fc, efivarfs_fill_super);
}

static int efivarfs_reconfigure(struct fs_context *fc)
{
	if (!efivar_supports_writes() && !(fc->sb_flags & SB_RDONLY)) {
		pr_err("Firmware does not support SetVariableRT. Can not remount with rw\n");
		return -EINVAL;
	}

	return 0;
}

static const struct fs_context_operations efivarfs_context_ops = {
	.get_tree	= efivarfs_get_tree,
	.parse_param	= efivarfs_parse_param,
	.reconfigure	= efivarfs_reconfigure,
};

static int efivarfs_init_fs_context(struct fs_context *fc)
{
	struct efivarfs_fs_info *sfi;

	if (!efivar_is_available())
		return -EOPNOTSUPP;

	sfi = kzalloc(sizeof(*sfi), GFP_KERNEL);
	if (!sfi)
		return -ENOMEM;

	INIT_LIST_HEAD(&sfi->efivarfs_list);

	sfi->mount_opts.uid = GLOBAL_ROOT_UID;
	sfi->mount_opts.gid = GLOBAL_ROOT_GID;

	fc->s_fs_info = sfi;
	fc->ops = &efivarfs_context_ops;
	return 0;
}

static void efivarfs_kill_sb(struct super_block *sb)
{
	struct efivarfs_fs_info *sfi = sb->s_fs_info;

	blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb);
	kill_litter_super(sb);

	/* Remove all entries and destroy */
	efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
	kfree(sfi);
}

static struct file_system_type efivarfs_type = {
	.owner   = THIS_MODULE,
	.name    = "efivarfs",
	.init_fs_context = efivarfs_init_fs_context,
	.kill_sb = efivarfs_kill_sb,
	.parameters = efivarfs_parameters,
};

static __init int efivarfs_init(void)
{
	return register_filesystem(&efivarfs_type);
}

static __exit void efivarfs_exit(void)
{
	unregister_filesystem(&efivarfs_type);
}

MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
MODULE_DESCRIPTION("EFI Variable Filesystem");
MODULE_LICENSE("GPL");
MODULE_ALIAS_FS("efivarfs");

module_init(efivarfs_init);
module_exit(efivarfs_exit);
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/ctype.h>
	8	#include <linux/efi.h>
	9	#include <linux/fs.h>
47999745	10	#include <linux/fs_context.h>
5329aa51	11	#include <linux/fs_parser.h>
d68772b7 MF	12	#include <linux/module.h>
d68772b7 MF	13	#include <linux/pagemap.h>
a614e192	14	#include <linux/ucs2_string.h>
20b4fb48 LT	15	#include <linux/slab.h>
20b4fb48 LT	16	#include <linux/magic.h>
d86ff333	17	#include <linux/statfs.h>
94f7f618	18	#include <linux/notifier.h>
0e8d2444	19	#include <linux/printk.h>
d68772b7 MF	20
	21	#include "internal.h"
	22
94f7f618 MK	23	static int efivarfs_ops_notifier(struct notifier_block *nb, unsigned long event,
	24	void *data)
	25	{
	26	struct efivarfs_fs_info *sfi = container_of(nb, struct efivarfs_fs_info, nb);
	27
	28	switch (event) {
	29	case EFIVAR_OPS_RDONLY:
	30	sfi->sb->s_flags \|= SB_RDONLY;
	31	break;
	32	case EFIVAR_OPS_RDWR:
	33	sfi->sb->s_flags &= ~SB_RDONLY;
	34	break;
	35	default:
	36	return NOTIFY_DONE;
	37	}
	38
	39	return NOTIFY_OK;
	40	}
	41
d68772b7 MF	42	static void efivarfs_evict_inode(struct inode *inode)
	43	{
	44	clear_inode(inode);
	45	}
	46
5329aa51 JZ	47	static int efivarfs_show_options(struct seq_file m, struct dentry root)
	48	{
	49	struct super_block *sb = root->d_sb;
	50	struct efivarfs_fs_info *sbi = sb->s_fs_info;
	51	struct efivarfs_mount_opts *opts = &sbi->mount_opts;
	52
	53	if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
	54	seq_printf(m, ",uid=%u",
	55	from_kuid_munged(&init_user_ns, opts->uid));
	56	if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
	57	seq_printf(m, ",gid=%u",
	58	from_kgid_munged(&init_user_ns, opts->gid));
	59	return 0;
	60	}
	61
d86ff333 AA	62	static int efivarfs_statfs(struct dentry dentry, struct kstatfs buf)
	63	{
	64	const u32 attr = EFI_VARIABLE_NON_VOLATILE \|
	65	EFI_VARIABLE_BOOTSERVICE_ACCESS \|
	66	EFI_VARIABLE_RUNTIME_ACCESS;
	67	u64 storage_space, remaining_space, max_variable_size;
ae62bcb5	68	u64 id = huge_encode_dev(dentry->d_sb->s_dev);
d86ff333 AA	69	efi_status_t status;
d86ff333 AA	70
79b83606 HS	71	/* Some UEFI firmware does not implement QueryVariableInfo() */
	72	storage_space = remaining_space = 0;
	73	if (efi_rt_services_supported(EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO)) {
	74	status = efivar_query_variable_info(attr, &storage_space,
	75	&remaining_space,
	76	&max_variable_size);
	77	if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED)
	78	pr_warn_ratelimited("query_variable_info() failed: 0x%lx\n",
	79	status);
	80	}
d86ff333 AA	81
	82	/*
	83	* This is not a normal filesystem, so no point in pretending it has a block
	84	* size; we declare f_bsize to 1, so that we can then report the exact value
	85	* sent by EFI QueryVariableInfo in f_blocks and f_bfree
	86	*/
	87	buf->f_bsize = 1;
	88	buf->f_namelen = NAME_MAX;
	89	buf->f_blocks = storage_space;
	90	buf->f_bfree = remaining_space;
	91	buf->f_type = dentry->d_sb->s_magic;
ae62bcb5	92	buf->f_fsid = u64_to_fsid(id);
d86ff333 AA	93
	94	/*
	95	* In f_bavail we declare the free space that the kernel will allow writing
	96	* when the storage_paranoia x86 quirk is active. To use more, users
	97	* should boot the kernel with efi_no_storage_paranoia.
	98	*/
	99	if (remaining_space > efivar_reserved_space())
	100	buf->f_bavail = remaining_space - efivar_reserved_space();
	101	else
	102	buf->f_bavail = 0;
	103
	104	return 0;
	105	}
d68772b7	106	static const struct super_operations efivarfs_ops = {
d86ff333	107	.statfs = efivarfs_statfs,
d68772b7 MF	108	.drop_inode = generic_delete_inode,
d68772b7 MF	109	.evict_inode = efivarfs_evict_inode,
5329aa51	110	.show_options = efivarfs_show_options,
d68772b7 MF	111	};
d68772b7 MF	112
d68772b7 MF	113	/*
	114	* Compare two efivarfs file names.
	115	*
	116	* An efivarfs filename is composed of two parts,
	117	*
	118	* 1. A case-sensitive variable name
	119	* 2. A case-insensitive GUID
	120	*
	121	* So we need to perform a case-sensitive match on part 1 and a
	122	* case-insensitive match on part 2.
	123	*/
6fa67e70	124	static int efivarfs_d_compare(const struct dentry *dentry,
d68772b7 MF	125	unsigned int len, const char *str,
	126	const struct qstr *name)
	127	{
	128	int guid = len - EFI_VARIABLE_GUID_LEN;
	129
	130	if (name->len != len)
	131	return 1;
	132
	133	/* Case-sensitive compare for the variable name */
	134	if (memcmp(str, name->name, guid))
	135	return 1;
	136
	137	/* Case-insensitive compare for the GUID */
	138	return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
	139	}
	140
da53be12	141	static int efivarfs_d_hash(const struct dentry dentry, struct qstr qstr)
d68772b7	142	{
8387ff25	143	unsigned long hash = init_name_hash(dentry);
d68772b7 MF	144	const unsigned char *s = qstr->name;
	145	unsigned int len = qstr->len;
	146
	147	if (!efivarfs_valid_name(s, len))
	148	return -EINVAL;
	149
	150	while (len-- > EFI_VARIABLE_GUID_LEN)
	151	hash = partial_name_hash(*s++, hash);
	152
	153	/* GUID is case-insensitive. */
	154	while (len--)
	155	hash = partial_name_hash(tolower(*s++), hash);
	156
	157	qstr->hash = end_name_hash(hash);
	158	return 0;
	159	}
	160
e37dcbfb	161	static const struct dentry_operations efivarfs_d_ops = {
d68772b7 MF	162	.d_compare = efivarfs_d_compare,
d68772b7 MF	163	.d_hash = efivarfs_d_hash,
b26d4cd3	164	.d_delete = always_delete_dentry,
d68772b7 MF	165	};
	166
	167	static struct dentry efivarfs_alloc_dentry(struct dentry parent, char *name)
	168	{
	169	struct dentry *d;
	170	struct qstr q;
	171	int err;
	172
	173	q.name = name;
	174	q.len = strlen(name);
	175
8387ff25	176	err = efivarfs_d_hash(parent, &q);
d68772b7 MF	177	if (err)
	178	return ERR_PTR(err);
	179
	180	d = d_alloc(parent, &q);
	181	if (d)
	182	return d;
	183
	184	return ERR_PTR(-ENOMEM);
	185	}
	186
	187	static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
cdb46a8a AB	188	unsigned long name_size, void *data,
cdb46a8a AB	189	struct list_head *list)
d68772b7 MF	190	{
	191	struct super_block sb = (struct super_block )data;
	192	struct efivar_entry *entry;
	193	struct inode *inode = NULL;
	194	struct dentry dentry, root = sb->s_root;
	195	unsigned long size = 0;
	196	char *name;
e0d64e6a	197	int len;
d68772b7	198	int err = -ENOMEM;
ed8b0de5	199	bool is_removable = false;
d68772b7	200
63ffb573 JD	201	if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
	202	return 0;
	203
c57dcb56	204	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
d68772b7 MF	205	if (!entry)
	206	return err;
	207
	208	memcpy(entry->var.VariableName, name16, name_size);
	209	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
	210
e0d64e6a	211	len = ucs2_utf8size(entry->var.VariableName);
d68772b7 MF	212
	213	/* name, plus '-', plus GUID, plus NUL*/
	214	name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
	215	if (!name)
	216	goto fail;
	217
e0d64e6a	218	ucs2_as_utf8(name, entry->var.VariableName, len);
d68772b7	219
ed8b0de5 PJ	220	if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
	221	is_removable = true;
	222
d68772b7 MF	223	name[len] = '-';
d68772b7 MF	224
26e02272	225	efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);
d68772b7 MF	226
	227	name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
	228
336af6a4 MS	229	/* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
	230	strreplace(name, '/', '!');
	231
ed8b0de5 PJ	232	inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG \| 0644, 0,
ed8b0de5 PJ	233	is_removable);
d68772b7 MF	234	if (!inode)
	235	goto fail_name;
	236
	237	dentry = efivarfs_alloc_dentry(root, name);
	238	if (IS_ERR(dentry)) {
	239	err = PTR_ERR(dentry);
	240	goto fail_inode;
	241	}
	242
ec3507b2	243	__efivar_entry_get(entry, NULL, &size, NULL);
cdb46a8a	244	__efivar_entry_add(entry, list);
d68772b7	245
22c2b77f MF	246	/* copied by the above to local storage in the dentry. */
	247	kfree(name);
	248
5955102c	249	inode_lock(inode);
d68772b7 MF	250	inode->i_private = entry;
d68772b7 MF	251	i_size_write(inode, size + sizeof(entry->var.Attributes));
5955102c	252	inode_unlock(inode);
d68772b7 MF	253	d_add(dentry, inode);
	254
	255	return 0;
	256
	257	fail_inode:
	258	iput(inode);
	259	fail_name:
	260	kfree(name);
	261	fail:
	262	kfree(entry);
	263	return err;
	264	}
	265
	266	static int efivarfs_destroy(struct efivar_entry entry, void data)
	267	{
3a75f9f2	268	efivar_entry_remove(entry);
d68772b7 MF	269	kfree(entry);
	270	return 0;
	271	}
	272
5329aa51 JZ	273	enum {
	274	Opt_uid, Opt_gid,
	275	};
	276
	277	static const struct fs_parameter_spec efivarfs_parameters[] = {
	278	fsparam_u32("uid", Opt_uid),
	279	fsparam_u32("gid", Opt_gid),
	280	{},
	281	};
	282
	283	static int efivarfs_parse_param(struct fs_context fc, struct fs_parameter param)
	284	{
	285	struct efivarfs_fs_info *sbi = fc->s_fs_info;
	286	struct efivarfs_mount_opts *opts = &sbi->mount_opts;
	287	struct fs_parse_result result;
	288	int opt;
	289
	290	opt = fs_parse(fc, efivarfs_parameters, param, &result);
	291	if (opt < 0)
	292	return opt;
	293
	294	switch (opt) {
	295	case Opt_uid:
	296	opts->uid = make_kuid(current_user_ns(), result.uint_32);
	297	if (!uid_valid(opts->uid))
	298	return -EINVAL;
	299	break;
	300	case Opt_gid:
	301	opts->gid = make_kgid(current_user_ns(), result.uint_32);
	302	if (!gid_valid(opts->gid))
	303	return -EINVAL;
	304	break;
	305	default:
	306	return -EINVAL;
	307	}
	308
	309	return 0;
	310	}
	311
47999745	312	static int efivarfs_fill_super(struct super_block sb, struct fs_context fc)
d68772b7	313	{
cdb46a8a	314	struct efivarfs_fs_info *sfi = sb->s_fs_info;
d68772b7 MF	315	struct inode *inode = NULL;
	316	struct dentry *root;
	317	int err;
	318
d68772b7	319	sb->s_maxbytes = MAX_LFS_FILESIZE;
09cbfeaf KS	320	sb->s_blocksize = PAGE_SIZE;
09cbfeaf KS	321	sb->s_blocksize_bits = PAGE_SHIFT;
d68772b7 MF	322	sb->s_magic = EFIVARFS_MAGIC;
	323	sb->s_op = &efivarfs_ops;
	324	sb->s_d_op = &efivarfs_d_ops;
	325	sb->s_time_gran = 1;
	326
f88814cc AB	327	if (!efivar_supports_writes())
	328	sb->s_flags \|= SB_RDONLY;
	329
ed8b0de5	330	inode = efivarfs_get_inode(sb, NULL, S_IFDIR \| 0755, 0, true);
d68772b7 MF	331	if (!inode)
	332	return -ENOMEM;
	333	inode->i_op = &efivarfs_dir_inode_operations;
	334
	335	root = d_make_root(inode);
	336	sb->s_root = root;
	337	if (!root)
	338	return -ENOMEM;
	339
94f7f618 MK	340	sfi->sb = sb;
	341	sfi->nb.notifier_call = efivarfs_ops_notifier;
	342	err = blocking_notifier_chain_register(&efivar_ops_nh, &sfi->nb);
	343	if (err)
	344	return err;
	345
2ce507f5	346	return efivar_init(efivarfs_callback, sb, &sfi->efivarfs_list);
d68772b7 MF	347	}
d68772b7 MF	348
47999745 DH	349	static int efivarfs_get_tree(struct fs_context *fc)
	350	{
	351	return get_tree_single(fc, efivarfs_fill_super);
	352	}
	353
0e8d2444 IA	354	static int efivarfs_reconfigure(struct fs_context *fc)
	355	{
	356	if (!efivar_supports_writes() && !(fc->sb_flags & SB_RDONLY)) {
	357	pr_err("Firmware does not support SetVariableRT. Can not remount with rw\n");
	358	return -EINVAL;
	359	}
	360
	361	return 0;
	362	}
	363
47999745 DH	364	static const struct fs_context_operations efivarfs_context_ops = {
47999745 DH	365	.get_tree = efivarfs_get_tree,
5329aa51	366	.parse_param = efivarfs_parse_param,
0e8d2444	367	.reconfigure = efivarfs_reconfigure,
47999745 DH	368	};
	369
	370	static int efivarfs_init_fs_context(struct fs_context *fc)
d68772b7	371	{
5329aa51 JZ	372	struct efivarfs_fs_info *sfi;
5329aa51 JZ	373
d28076dd AB	374	if (!efivar_is_available())
	375	return -EOPNOTSUPP;
	376
5329aa51 JZ	377	sfi = kzalloc(sizeof(*sfi), GFP_KERNEL);
	378	if (!sfi)
	379	return -ENOMEM;
	380
cdb46a8a AB	381	INIT_LIST_HEAD(&sfi->efivarfs_list);
cdb46a8a AB	382
5329aa51 JZ	383	sfi->mount_opts.uid = GLOBAL_ROOT_UID;
	384	sfi->mount_opts.gid = GLOBAL_ROOT_GID;
	385
	386	fc->s_fs_info = sfi;
47999745 DH	387	fc->ops = &efivarfs_context_ops;
47999745 DH	388	return 0;
d68772b7 MF	389	}
	390
	391	static void efivarfs_kill_sb(struct super_block *sb)
	392	{
547713d5 AB	393	struct efivarfs_fs_info *sfi = sb->s_fs_info;
547713d5 AB	394
94f7f618	395	blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb);
d68772b7	396	kill_litter_super(sb);
d68772b7 MF	397
d68772b7 MF	398	/* Remove all entries and destroy */
cdb46a8a	399	efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
547713d5	400	kfree(sfi);
d68772b7 MF	401	}
	402
	403	static struct file_system_type efivarfs_type = {
af5a29ae	404	.owner = THIS_MODULE,
d68772b7	405	.name = "efivarfs",
47999745	406	.init_fs_context = efivarfs_init_fs_context,
d68772b7	407	.kill_sb = efivarfs_kill_sb,
5329aa51	408	.parameters = efivarfs_parameters,
d68772b7 MF	409	};
	410
	411	static __init int efivarfs_init(void)
	412	{
d68772b7 MF	413	return register_filesystem(&efivarfs_type);
	414	}
	415
af5a29ae MK	416	static __exit void efivarfs_exit(void)
	417	{
	418	unregister_filesystem(&efivarfs_type);
	419	}
	420
d68772b7 MF	421	MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
	422	MODULE_DESCRIPTION("EFI Variable Filesystem");
	423	MODULE_LICENSE("GPL");
	424	MODULE_ALIAS_FS("efivarfs");
	425
	426	module_init(efivarfs_init);
af5a29ae	427	module_exit(efivarfs_exit);