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2ce507f57b
The 'duplicates' bool argument is always true when efivar_init() is called from its only caller so let's just drop it instead. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
428 lines
10 KiB
C
428 lines
10 KiB
C
// 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/ctype.h>
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#include <linux/efi.h>
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#include <linux/fs.h>
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#include <linux/fs_context.h>
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#include <linux/fs_parser.h>
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#include <linux/module.h>
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#include <linux/pagemap.h>
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#include <linux/ucs2_string.h>
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#include <linux/slab.h>
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#include <linux/magic.h>
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#include <linux/statfs.h>
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#include <linux/notifier.h>
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#include <linux/printk.h>
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#include "internal.h"
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static int efivarfs_ops_notifier(struct notifier_block *nb, unsigned long event,
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void *data)
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{
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struct efivarfs_fs_info *sfi = container_of(nb, struct efivarfs_fs_info, nb);
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switch (event) {
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case EFIVAR_OPS_RDONLY:
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sfi->sb->s_flags |= SB_RDONLY;
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break;
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case EFIVAR_OPS_RDWR:
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sfi->sb->s_flags &= ~SB_RDONLY;
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break;
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default:
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return NOTIFY_DONE;
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}
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return NOTIFY_OK;
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}
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static void efivarfs_evict_inode(struct inode *inode)
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{
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clear_inode(inode);
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}
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static int efivarfs_show_options(struct seq_file *m, struct dentry *root)
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{
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struct super_block *sb = root->d_sb;
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struct efivarfs_fs_info *sbi = sb->s_fs_info;
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struct efivarfs_mount_opts *opts = &sbi->mount_opts;
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if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
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seq_printf(m, ",uid=%u",
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from_kuid_munged(&init_user_ns, opts->uid));
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if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
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seq_printf(m, ",gid=%u",
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from_kgid_munged(&init_user_ns, opts->gid));
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return 0;
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}
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static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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const u32 attr = EFI_VARIABLE_NON_VOLATILE |
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EFI_VARIABLE_BOOTSERVICE_ACCESS |
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EFI_VARIABLE_RUNTIME_ACCESS;
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u64 storage_space, remaining_space, max_variable_size;
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u64 id = huge_encode_dev(dentry->d_sb->s_dev);
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efi_status_t status;
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/* Some UEFI firmware does not implement QueryVariableInfo() */
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storage_space = remaining_space = 0;
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if (efi_rt_services_supported(EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO)) {
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status = efivar_query_variable_info(attr, &storage_space,
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&remaining_space,
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&max_variable_size);
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if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED)
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pr_warn_ratelimited("query_variable_info() failed: 0x%lx\n",
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status);
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}
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/*
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* This is not a normal filesystem, so no point in pretending it has a block
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* size; we declare f_bsize to 1, so that we can then report the exact value
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* sent by EFI QueryVariableInfo in f_blocks and f_bfree
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*/
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buf->f_bsize = 1;
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buf->f_namelen = NAME_MAX;
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buf->f_blocks = storage_space;
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buf->f_bfree = remaining_space;
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buf->f_type = dentry->d_sb->s_magic;
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buf->f_fsid = u64_to_fsid(id);
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/*
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* In f_bavail we declare the free space that the kernel will allow writing
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* when the storage_paranoia x86 quirk is active. To use more, users
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* should boot the kernel with efi_no_storage_paranoia.
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*/
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if (remaining_space > efivar_reserved_space())
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buf->f_bavail = remaining_space - efivar_reserved_space();
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else
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buf->f_bavail = 0;
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return 0;
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}
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static const struct super_operations efivarfs_ops = {
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.statfs = efivarfs_statfs,
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.drop_inode = generic_delete_inode,
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.evict_inode = efivarfs_evict_inode,
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.show_options = efivarfs_show_options,
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};
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/*
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* Compare two efivarfs file names.
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*
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* An efivarfs filename is composed of two parts,
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*
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* 1. A case-sensitive variable name
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* 2. A case-insensitive GUID
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*
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* So we need to perform a case-sensitive match on part 1 and a
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* case-insensitive match on part 2.
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*/
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static int efivarfs_d_compare(const struct dentry *dentry,
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unsigned int len, const char *str,
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const struct qstr *name)
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{
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int guid = len - EFI_VARIABLE_GUID_LEN;
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if (name->len != len)
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return 1;
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/* Case-sensitive compare for the variable name */
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if (memcmp(str, name->name, guid))
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return 1;
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/* Case-insensitive compare for the GUID */
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return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
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}
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static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr)
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{
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unsigned long hash = init_name_hash(dentry);
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const unsigned char *s = qstr->name;
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unsigned int len = qstr->len;
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if (!efivarfs_valid_name(s, len))
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return -EINVAL;
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while (len-- > EFI_VARIABLE_GUID_LEN)
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hash = partial_name_hash(*s++, hash);
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/* GUID is case-insensitive. */
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while (len--)
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hash = partial_name_hash(tolower(*s++), hash);
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qstr->hash = end_name_hash(hash);
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return 0;
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}
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static const struct dentry_operations efivarfs_d_ops = {
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.d_compare = efivarfs_d_compare,
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.d_hash = efivarfs_d_hash,
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.d_delete = always_delete_dentry,
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};
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static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
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{
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struct dentry *d;
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struct qstr q;
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int err;
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q.name = name;
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q.len = strlen(name);
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err = efivarfs_d_hash(parent, &q);
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if (err)
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return ERR_PTR(err);
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d = d_alloc(parent, &q);
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if (d)
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return d;
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return ERR_PTR(-ENOMEM);
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}
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static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
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unsigned long name_size, void *data,
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struct list_head *list)
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{
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struct super_block *sb = (struct super_block *)data;
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struct efivar_entry *entry;
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struct inode *inode = NULL;
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struct dentry *dentry, *root = sb->s_root;
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unsigned long size = 0;
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char *name;
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int len;
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int err = -ENOMEM;
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bool is_removable = false;
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if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
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return 0;
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entry = kzalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry)
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return err;
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memcpy(entry->var.VariableName, name16, name_size);
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memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
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len = ucs2_utf8size(entry->var.VariableName);
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/* name, plus '-', plus GUID, plus NUL*/
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name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
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if (!name)
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goto fail;
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ucs2_as_utf8(name, entry->var.VariableName, len);
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if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
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is_removable = true;
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name[len] = '-';
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efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);
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name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
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/* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
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strreplace(name, '/', '!');
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inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
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is_removable);
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if (!inode)
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goto fail_name;
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dentry = efivarfs_alloc_dentry(root, name);
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if (IS_ERR(dentry)) {
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err = PTR_ERR(dentry);
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goto fail_inode;
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}
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__efivar_entry_get(entry, NULL, &size, NULL);
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__efivar_entry_add(entry, list);
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/* copied by the above to local storage in the dentry. */
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kfree(name);
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inode_lock(inode);
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inode->i_private = entry;
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i_size_write(inode, size + sizeof(entry->var.Attributes));
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inode_unlock(inode);
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d_add(dentry, inode);
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return 0;
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fail_inode:
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iput(inode);
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fail_name:
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kfree(name);
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fail:
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kfree(entry);
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return err;
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}
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static int efivarfs_destroy(struct efivar_entry *entry, void *data)
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{
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efivar_entry_remove(entry);
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kfree(entry);
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return 0;
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}
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enum {
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Opt_uid, Opt_gid,
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};
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static const struct fs_parameter_spec efivarfs_parameters[] = {
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fsparam_u32("uid", Opt_uid),
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fsparam_u32("gid", Opt_gid),
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{},
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};
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static int efivarfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
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{
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struct efivarfs_fs_info *sbi = fc->s_fs_info;
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struct efivarfs_mount_opts *opts = &sbi->mount_opts;
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struct fs_parse_result result;
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int opt;
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opt = fs_parse(fc, efivarfs_parameters, param, &result);
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if (opt < 0)
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return opt;
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switch (opt) {
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case Opt_uid:
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opts->uid = make_kuid(current_user_ns(), result.uint_32);
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if (!uid_valid(opts->uid))
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return -EINVAL;
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break;
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case Opt_gid:
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opts->gid = make_kgid(current_user_ns(), result.uint_32);
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if (!gid_valid(opts->gid))
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return -EINVAL;
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
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{
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struct efivarfs_fs_info *sfi = sb->s_fs_info;
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struct inode *inode = NULL;
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struct dentry *root;
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int err;
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sb->s_maxbytes = MAX_LFS_FILESIZE;
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sb->s_blocksize = PAGE_SIZE;
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sb->s_blocksize_bits = PAGE_SHIFT;
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sb->s_magic = EFIVARFS_MAGIC;
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sb->s_op = &efivarfs_ops;
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sb->s_d_op = &efivarfs_d_ops;
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sb->s_time_gran = 1;
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if (!efivar_supports_writes())
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sb->s_flags |= SB_RDONLY;
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inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true);
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if (!inode)
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return -ENOMEM;
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inode->i_op = &efivarfs_dir_inode_operations;
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root = d_make_root(inode);
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sb->s_root = root;
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if (!root)
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return -ENOMEM;
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sfi->sb = sb;
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sfi->nb.notifier_call = efivarfs_ops_notifier;
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err = blocking_notifier_chain_register(&efivar_ops_nh, &sfi->nb);
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if (err)
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return err;
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return efivar_init(efivarfs_callback, sb, &sfi->efivarfs_list);
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}
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static int efivarfs_get_tree(struct fs_context *fc)
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{
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return get_tree_single(fc, efivarfs_fill_super);
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}
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static int efivarfs_reconfigure(struct fs_context *fc)
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{
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if (!efivar_supports_writes() && !(fc->sb_flags & SB_RDONLY)) {
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pr_err("Firmware does not support SetVariableRT. Can not remount with rw\n");
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return -EINVAL;
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}
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return 0;
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}
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static const struct fs_context_operations efivarfs_context_ops = {
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.get_tree = efivarfs_get_tree,
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.parse_param = efivarfs_parse_param,
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.reconfigure = efivarfs_reconfigure,
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};
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static int efivarfs_init_fs_context(struct fs_context *fc)
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{
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struct efivarfs_fs_info *sfi;
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if (!efivar_is_available())
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return -EOPNOTSUPP;
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sfi = kzalloc(sizeof(*sfi), GFP_KERNEL);
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if (!sfi)
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return -ENOMEM;
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INIT_LIST_HEAD(&sfi->efivarfs_list);
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sfi->mount_opts.uid = GLOBAL_ROOT_UID;
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sfi->mount_opts.gid = GLOBAL_ROOT_GID;
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fc->s_fs_info = sfi;
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fc->ops = &efivarfs_context_ops;
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return 0;
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}
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static void efivarfs_kill_sb(struct super_block *sb)
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{
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struct efivarfs_fs_info *sfi = sb->s_fs_info;
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blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb);
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kill_litter_super(sb);
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/* Remove all entries and destroy */
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efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
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kfree(sfi);
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}
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static struct file_system_type efivarfs_type = {
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.owner = THIS_MODULE,
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.name = "efivarfs",
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.init_fs_context = efivarfs_init_fs_context,
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.kill_sb = efivarfs_kill_sb,
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.parameters = efivarfs_parameters,
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};
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static __init int efivarfs_init(void)
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{
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return register_filesystem(&efivarfs_type);
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}
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static __exit void efivarfs_exit(void)
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{
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unregister_filesystem(&efivarfs_type);
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}
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MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
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MODULE_DESCRIPTION("EFI Variable Filesystem");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_FS("efivarfs");
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module_init(efivarfs_init);
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module_exit(efivarfs_exit);
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