diff options
Diffstat (limited to 'fs/efivarfs')
| -rw-r--r-- | fs/efivarfs/Kconfig | 12 | ||||
| -rw-r--r-- | fs/efivarfs/Makefile | 7 | ||||
| -rw-r--r-- | fs/efivarfs/file.c | 105 | ||||
| -rw-r--r-- | fs/efivarfs/inode.c | 173 | ||||
| -rw-r--r-- | fs/efivarfs/internal.h | 22 | ||||
| -rw-r--r-- | fs/efivarfs/super.c | 268 |
6 files changed, 587 insertions, 0 deletions
diff --git a/fs/efivarfs/Kconfig b/fs/efivarfs/Kconfig new file mode 100644 index 0000000..367bbb1 --- /dev/null +++ b/fs/efivarfs/Kconfig @@ -0,0 +1,12 @@ +config EFIVAR_FS + tristate "EFI Variable filesystem" + depends on EFI + help + efivarfs is a replacement filesystem for the old EFI + variable support via sysfs, as it doesn't suffer from the + same 1024-byte variable size limit. + + To compile this file system support as a module, choose M + here. The module will be called efivarfs. + + If unsure, say N. diff --git a/fs/efivarfs/Makefile b/fs/efivarfs/Makefile new file mode 100644 index 0000000..955d478 --- /dev/null +++ b/fs/efivarfs/Makefile @@ -0,0 +1,7 @@ +# +# Makefile for the efivarfs filesystem +# + +obj-$(CONFIG_EFIVAR_FS) += efivarfs.o + +efivarfs-objs := inode.o file.o super.o diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c new file mode 100644 index 0000000..ede07fc --- /dev/null +++ b/fs/efivarfs/file.c @@ -0,0 +1,105 @@ +/* + * Copyright (C) 2012 Red Hat, Inc. + * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/efi.h> +#include <linux/fs.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 = 0; + 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 = kmalloc(datasize, GFP_KERNEL); + if (!data) + return -ENOMEM; + + if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) { + bytes = -EFAULT; + goto out; + } + + bytes = efivar_entry_set_get_size(var, attributes, &datasize, + data, &set); + if (!set && bytes) + goto out; + + if (bytes == -ENOENT) { + drop_nlink(inode); + d_delete(file->f_dentry); + dput(file->f_dentry); + } else { + mutex_lock(&inode->i_mutex); + i_size_write(inode, datasize + sizeof(attributes)); + mutex_unlock(&inode->i_mutex); + } + + 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; + + err = efivar_entry_size(var, &datasize); + 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; +} + +const struct file_operations efivarfs_file_operations = { + .open = simple_open, + .read = efivarfs_file_read, + .write = efivarfs_file_write, + .llseek = no_llseek, +}; diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c new file mode 100644 index 0000000..640e289 --- /dev/null +++ b/fs/efivarfs/inode.c @@ -0,0 +1,173 @@ +/* + * Copyright (C) 2012 Red Hat, Inc. + * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/efi.h> +#include <linux/fs.h> +#include <linux/ctype.h> + +#include "internal.h" + +struct inode *efivarfs_get_inode(struct super_block *sb, + const struct inode *dir, int mode, dev_t dev) +{ + 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; + switch (mode & S_IFMT) { + case S_IFREG: + 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) +{ + static const char dashes[EFI_VARIABLE_GUID_LEN] = { + [8] = 1, [13] = 1, [18] = 1, [23] = 1 + }; + const char *s = str + len - EFI_VARIABLE_GUID_LEN; + int i; + + /* + * 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 + */ + for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) { + if (dashes[i]) { + if (*s++ != '-') + return false; + } else { + if (!isxdigit(*s++)) + return false; + } + } + + return true; +} + +static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid) +{ + guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]); + guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]); + guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]); + guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]); + guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]); + guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]); + guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]); + guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]); + guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]); + guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]); + guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]); + guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]); + guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]); + guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]); + guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]); + guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]); +} + +static int efivarfs_create(struct inode *dir, struct dentry *dentry, + umode_t mode, bool excl) +{ + struct inode *inode; + struct efivar_entry *var; + int namelen, i = 0, err = 0; + + if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) + return -EINVAL; + + inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0); + if (!inode) + return -ENOMEM; + + var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); + if (!var) { + err = -ENOMEM; + goto out; + } + + /* length of the variable name itself: remove GUID and separator */ + namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; + + efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1, + &var->var.VendorGuid); + + for (i = 0; i < namelen; i++) + var->var.VariableName[i] = dentry->d_name.name[i]; + + var->var.VariableName[i] = '\0'; + + inode->i_private = var; + + efivar_entry_add(var, &efivarfs_list); + d_instantiate(dentry, inode); + dget(dentry); +out: + if (err) { + kfree(var); + iput(inode); + } + return err; +} + +static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) +{ + struct efivar_entry *var = dentry->d_inode->i_private; + + if (efivar_entry_delete(var)) + return -EINVAL; + + drop_nlink(dentry->d_inode); + dput(dentry); + return 0; +}; + +/* + * Handle negative dentry. + */ +static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + if (dentry->d_name.len > NAME_MAX) + return ERR_PTR(-ENAMETOOLONG); + d_add(dentry, NULL); + return NULL; +} + +const struct inode_operations efivarfs_dir_inode_operations = { + .lookup = efivarfs_lookup, + .unlink = efivarfs_unlink, + .create = efivarfs_create, +}; diff --git a/fs/efivarfs/internal.h b/fs/efivarfs/internal.h new file mode 100644 index 0000000..b5ff16a --- /dev/null +++ b/fs/efivarfs/internal.h @@ -0,0 +1,22 @@ +/* + * Copyright (C) 2012 Red Hat, Inc. + * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#ifndef EFIVAR_FS_INTERNAL_H +#define EFIVAR_FS_INTERNAL_H + +#include <linux/list.h> + +extern const struct file_operations efivarfs_file_operations; +extern const struct inode_operations efivarfs_dir_inode_operations; +extern bool efivarfs_valid_name(const char *str, int len); +extern struct inode *efivarfs_get_inode(struct super_block *sb, + const struct inode *dir, int mode, dev_t dev); + +extern struct list_head efivarfs_list; + +#endif /* EFIVAR_FS_INTERNAL_H */ diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c new file mode 100644 index 0000000..525a2a1 --- /dev/null +++ b/fs/efivarfs/super.c @@ -0,0 +1,268 @@ +/* + * Copyright (C) 2012 Red Hat, Inc. + * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/ctype.h> +#include <linux/efi.h> +#include <linux/fs.h> +#include <linux/module.h> +#include <linux/pagemap.h> +#include <linux/ucs2_string.h> + +#include "internal.h" + +LIST_HEAD(efivarfs_list); + +static void efivarfs_evict_inode(struct inode *inode) +{ + clear_inode(inode); +} + +static const struct super_operations efivarfs_ops = { + .statfs = simple_statfs, + .drop_inode = generic_delete_inode, + .evict_inode = efivarfs_evict_inode, + .show_options = generic_show_options, +}; + +static struct super_block *efivarfs_sb; + +/* + * 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 *parent, const struct inode *pinode, + const struct dentry *dentry, const struct inode *inode, + 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, + const struct inode *inode, struct qstr *qstr) +{ + unsigned long hash = init_name_hash(); + 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; +} + +/* + * Retaining negative dentries for an in-memory filesystem just wastes + * memory and lookup time: arrange for them to be deleted immediately. + */ +static int efivarfs_delete_dentry(const struct dentry *dentry) +{ + return 1; +} + +static struct dentry_operations efivarfs_d_ops = { + .d_compare = efivarfs_d_compare, + .d_hash = efivarfs_d_hash, + .d_delete = efivarfs_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(NULL, NULL, &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 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, i; + int err = -ENOMEM; + + entry = kmalloc(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_strlen(entry->var.VariableName); + + /* name, plus '-', plus GUID, plus NUL*/ + name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL); + if (!name) + goto fail; + + for (i = 0; i < len; i++) + name[i] = entry->var.VariableName[i] & 0xFF; + + name[len] = '-'; + + efi_guid_unparse(&entry->var.VendorGuid, name + len + 1); + + name[len + EFI_VARIABLE_GUID_LEN+1] = '\0'; + + inode = efivarfs_get_inode(sb, root->d_inode, S_IFREG | 0644, 0); + if (!inode) + goto fail_name; + + dentry = efivarfs_alloc_dentry(root, name); + if (IS_ERR(dentry)) { + err = PTR_ERR(dentry); + goto fail_inode; + } + + /* copied by the above to local storage in the dentry. */ + kfree(name); + + efivar_entry_size(entry, &size); + efivar_entry_add(entry, &efivarfs_list); + + mutex_lock(&inode->i_mutex); + inode->i_private = entry; + i_size_write(inode, size + sizeof(entry->var.Attributes)); + mutex_unlock(&inode->i_mutex); + 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; +} + +static int efivarfs_fill_super(struct super_block *sb, void *data, int silent) +{ + struct inode *inode = NULL; + struct dentry *root; + int err; + + efivarfs_sb = sb; + + sb->s_maxbytes = MAX_LFS_FILESIZE; + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = EFIVARFS_MAGIC; + sb->s_op = &efivarfs_ops; + sb->s_d_op = &efivarfs_d_ops; + sb->s_time_gran = 1; + + inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0); + if (!inode) + return -ENOMEM; + inode->i_op = &efivarfs_dir_inode_operations; + + root = d_make_root(inode); + sb->s_root = root; + if (!root) + return -ENOMEM; + + INIT_LIST_HEAD(&efivarfs_list); + + err = efivar_init(efivarfs_callback, (void *)sb, false, + true, &efivarfs_list); + if (err) + __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL); + + return err; +} + +static struct dentry *efivarfs_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + return mount_single(fs_type, flags, data, efivarfs_fill_super); +} + +static void efivarfs_kill_sb(struct super_block *sb) +{ + kill_litter_super(sb); + efivarfs_sb = NULL; + + /* Remove all entries and destroy */ + __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL); +} + +static struct file_system_type efivarfs_type = { + .name = "efivarfs", + .mount = efivarfs_mount, + .kill_sb = efivarfs_kill_sb, +}; + +static __init int efivarfs_init(void) +{ + if (!efi_enabled(EFI_RUNTIME_SERVICES)) + return 0; + + if (!efivars_kobject()) + return 0; + + return register_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); |
