android_kernel_xiaomi_sm8350/fs/ecryptfs/main.c

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/**
* eCryptfs: Linux filesystem encryption layer
*
* Copyright (C) 1997-2003 Erez Zadok
* Copyright (C) 2001-2003 Stony Brook University
* Copyright (C) 2004-2007 International Business Machines Corp.
* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
* Michael C. Thompson <mcthomps@us.ibm.com>
* Tyler Hicks <tyhicks@ou.edu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <linux/dcache.h>
#include <linux/file.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/skbuff.h>
#include <linux/crypto.h>
#include <linux/netlink.h>
#include <linux/mount.h>
#include <linux/dcache.h>
#include <linux/pagemap.h>
#include <linux/key.h>
#include <linux/parser.h>
#include <linux/fs_stack.h>
#include "ecryptfs_kernel.h"
/**
* Module parameter that defines the ecryptfs_verbosity level.
*/
int ecryptfs_verbosity = 0;
module_param(ecryptfs_verbosity, int, 0);
MODULE_PARM_DESC(ecryptfs_verbosity,
"Initial verbosity level (0 or 1; defaults to "
"0, which is Quiet)");
/**
* Module parameter that defines the number of netlink message buffer
* elements
*/
unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
module_param(ecryptfs_message_buf_len, uint, 0);
MODULE_PARM_DESC(ecryptfs_message_buf_len,
"Number of message buffer elements");
/**
* Module parameter that defines the maximum guaranteed amount of time to wait
* for a response through netlink. The actual sleep time will be, more than
* likely, a small amount greater than this specified value, but only less if
* the netlink message successfully arrives.
*/
signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
module_param(ecryptfs_message_wait_timeout, long, 0);
MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
"Maximum number of seconds that an operation will "
"sleep while waiting for a message response from "
"userspace");
/**
* Module parameter that is an estimate of the maximum number of users
* that will be concurrently using eCryptfs. Set this to the right
* value to balance performance and memory use.
*/
unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
module_param(ecryptfs_number_of_users, uint, 0);
MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
"concurrent users of eCryptfs");
unsigned int ecryptfs_transport = ECRYPTFS_DEFAULT_TRANSPORT;
void __ecryptfs_printk(const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
if (fmt[1] == '7') { /* KERN_DEBUG */
if (ecryptfs_verbosity >= 1)
vprintk(fmt, args);
} else
vprintk(fmt, args);
va_end(args);
}
/**
* ecryptfs_interpose
* @lower_dentry: Existing dentry in the lower filesystem
* @dentry: ecryptfs' dentry
* @sb: ecryptfs's super_block
* @flag: If set to true, then d_add is called, else d_instantiate is called
*
* Interposes upper and lower dentries.
*
* Returns zero on success; non-zero otherwise
*/
int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
struct super_block *sb, int flag)
{
struct inode *lower_inode;
struct inode *inode;
int rc = 0;
lower_inode = lower_dentry->d_inode;
if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
rc = -EXDEV;
goto out;
}
if (!igrab(lower_inode)) {
rc = -ESTALE;
goto out;
}
inode = iget5_locked(sb, (unsigned long)lower_inode,
ecryptfs_inode_test, ecryptfs_inode_set,
lower_inode);
if (!inode) {
rc = -EACCES;
iput(lower_inode);
goto out;
}
if (inode->i_state & I_NEW)
unlock_new_inode(inode);
else
iput(lower_inode);
if (S_ISLNK(lower_inode->i_mode))
inode->i_op = &ecryptfs_symlink_iops;
else if (S_ISDIR(lower_inode->i_mode))
inode->i_op = &ecryptfs_dir_iops;
if (S_ISDIR(lower_inode->i_mode))
inode->i_fop = &ecryptfs_dir_fops;
if (special_file(lower_inode->i_mode))
init_special_inode(inode, lower_inode->i_mode,
lower_inode->i_rdev);
dentry->d_op = &ecryptfs_dops;
if (flag)
d_add(dentry, inode);
else
d_instantiate(dentry, inode);
fsstack_copy_attr_all(inode, lower_inode, NULL);
/* This size will be overwritten for real files w/ headers and
* other metadata */
fsstack_copy_inode_size(inode, lower_inode);
out:
return rc;
}
enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig, ecryptfs_opt_debug,
ecryptfs_opt_ecryptfs_debug, ecryptfs_opt_cipher,
ecryptfs_opt_ecryptfs_cipher, ecryptfs_opt_ecryptfs_key_bytes,
[PATCH] eCryptfs: xattr flags and mount options This patch set introduces the ability to store cryptographic metadata into an lower file extended attribute rather than the lower file header region. This patch set implements two new mount options: ecryptfs_xattr_metadata - When set, newly created files will have their cryptographic metadata stored in the extended attribute region of the file rather than the header. When storing the data in the file header, there is a minimum of 8KB reserved for the header information for each file, making each file at least 12KB in size. This can take up a lot of extra disk space if the user creates a lot of small files. By storing the data in the extended attribute, each file will only occupy at least of 4KB of space. As the eCryptfs metadata set becomes larger with new features such as multi-key associations, most popular filesystems will not be able to store all of the information in the xattr region in some cases due to space constraints. However, the majority of users will only ever associate one key per file, so most users will be okay with storing their data in the xattr region. This option should be used with caution. I want to emphasize that the xattr must be maintained under all circumstances, or the file will be rendered permanently unrecoverable. The last thing I want is for a user to forget to set an xattr flag in a backup utility, only to later discover that their backups are worthless. ecryptfs_encrypted_view - When set, this option causes eCryptfs to present applications a view of encrypted files as if the cryptographic metadata were stored in the file header, whether the metadata is actually stored in the header or in the extended attributes. No matter what eCryptfs winds up doing in the lower filesystem, I want to preserve a baseline format compatibility for the encrypted files. As of right now, the metadata may be in the file header or in an xattr. There is no reason why the metadata could not be put in a separate file in future versions. Without the compatibility mode, backup utilities would have to know to back up the metadata file along with the files. The semantics of eCryptfs have always been that the lower files are self-contained units of encrypted data, and the only additional information required to decrypt any given eCryptfs file is the key. That is what has always been emphasized about eCryptfs lower files, and that is what users expect. Providing the encrypted view option will provide a way to userspace applications wherein they can always get to the same old familiar eCryptfs encrypted files, regardless of what eCryptfs winds up doing with the metadata behind the scenes. This patch: Add extended attribute support to version bit vector, flags to indicate when xattr or encrypted view modes are enabled, and support for the new mount options. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 03:53:45 -05:00
ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
ecryptfs_opt_encrypted_view, ecryptfs_opt_err };
static match_table_t tokens = {
{ecryptfs_opt_sig, "sig=%s"},
{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
{ecryptfs_opt_debug, "debug=%u"},
{ecryptfs_opt_ecryptfs_debug, "ecryptfs_debug=%u"},
{ecryptfs_opt_cipher, "cipher=%s"},
{ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
{ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
{ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
[PATCH] eCryptfs: xattr flags and mount options This patch set introduces the ability to store cryptographic metadata into an lower file extended attribute rather than the lower file header region. This patch set implements two new mount options: ecryptfs_xattr_metadata - When set, newly created files will have their cryptographic metadata stored in the extended attribute region of the file rather than the header. When storing the data in the file header, there is a minimum of 8KB reserved for the header information for each file, making each file at least 12KB in size. This can take up a lot of extra disk space if the user creates a lot of small files. By storing the data in the extended attribute, each file will only occupy at least of 4KB of space. As the eCryptfs metadata set becomes larger with new features such as multi-key associations, most popular filesystems will not be able to store all of the information in the xattr region in some cases due to space constraints. However, the majority of users will only ever associate one key per file, so most users will be okay with storing their data in the xattr region. This option should be used with caution. I want to emphasize that the xattr must be maintained under all circumstances, or the file will be rendered permanently unrecoverable. The last thing I want is for a user to forget to set an xattr flag in a backup utility, only to later discover that their backups are worthless. ecryptfs_encrypted_view - When set, this option causes eCryptfs to present applications a view of encrypted files as if the cryptographic metadata were stored in the file header, whether the metadata is actually stored in the header or in the extended attributes. No matter what eCryptfs winds up doing in the lower filesystem, I want to preserve a baseline format compatibility for the encrypted files. As of right now, the metadata may be in the file header or in an xattr. There is no reason why the metadata could not be put in a separate file in future versions. Without the compatibility mode, backup utilities would have to know to back up the metadata file along with the files. The semantics of eCryptfs have always been that the lower files are self-contained units of encrypted data, and the only additional information required to decrypt any given eCryptfs file is the key. That is what has always been emphasized about eCryptfs lower files, and that is what users expect. Providing the encrypted view option will provide a way to userspace applications wherein they can always get to the same old familiar eCryptfs encrypted files, regardless of what eCryptfs winds up doing with the metadata behind the scenes. This patch: Add extended attribute support to version bit vector, flags to indicate when xattr or encrypted view modes are enabled, and support for the new mount options. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 03:53:45 -05:00
{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
{ecryptfs_opt_err, NULL}
};
static int ecryptfs_init_global_auth_toks(
struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
struct ecryptfs_global_auth_tok *global_auth_tok;
int rc = 0;
list_for_each_entry(global_auth_tok,
&mount_crypt_stat->global_auth_tok_list,
mount_crypt_stat_list) {
if ((rc = ecryptfs_keyring_auth_tok_for_sig(
&global_auth_tok->global_auth_tok_key,
&global_auth_tok->global_auth_tok,
global_auth_tok->sig))) {
printk(KERN_ERR "Could not find valid key in user "
"session keyring for sig specified in mount "
"option: [%s]\n", global_auth_tok->sig);
global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
rc = 0;
} else
global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
}
return rc;
}
static void ecryptfs_init_mount_crypt_stat(
struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
memset((void *)mount_crypt_stat, 0,
sizeof(struct ecryptfs_mount_crypt_stat));
INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
}
/**
* ecryptfs_parse_options
* @sb: The ecryptfs super block
* @options: The options pased to the kernel
*
* Parse mount options:
* debug=N - ecryptfs_verbosity level for debug output
* sig=XXX - description(signature) of the key to use
*
* Returns the dentry object of the lower-level (lower/interposed)
* directory; We want to mount our stackable file system on top of
* that lower directory.
*
* The signature of the key to use must be the description of a key
* already in the keyring. Mounting will fail if the key can not be
* found.
*
* Returns zero on success; non-zero on error
*/
static int ecryptfs_parse_options(struct super_block *sb, char *options)
{
char *p;
int rc = 0;
int sig_set = 0;
int cipher_name_set = 0;
int cipher_key_bytes;
int cipher_key_bytes_set = 0;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
&ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
substring_t args[MAX_OPT_ARGS];
int token;
char *sig_src;
char *debug_src;
char *cipher_name_dst;
char *cipher_name_src;
char *cipher_key_bytes_src;
int cipher_name_len;
if (!options) {
rc = -EINVAL;
goto out;
}
ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
while ((p = strsep(&options, ",")) != NULL) {
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case ecryptfs_opt_sig:
case ecryptfs_opt_ecryptfs_sig:
sig_src = args[0].from;
rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
sig_src);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global sig; rc = [%d]\n", rc);
goto out;
}
sig_set = 1;
break;
case ecryptfs_opt_debug:
case ecryptfs_opt_ecryptfs_debug:
debug_src = args[0].from;
ecryptfs_verbosity =
(int)simple_strtol(debug_src, &debug_src,
0);
ecryptfs_printk(KERN_DEBUG,
"Verbosity set to [%d]" "\n",
ecryptfs_verbosity);
break;
case ecryptfs_opt_cipher:
case ecryptfs_opt_ecryptfs_cipher:
cipher_name_src = args[0].from;
cipher_name_dst =
mount_crypt_stat->
global_default_cipher_name;
strncpy(cipher_name_dst, cipher_name_src,
ECRYPTFS_MAX_CIPHER_NAME_SIZE);
ecryptfs_printk(KERN_DEBUG,
"The mount_crypt_stat "
"global_default_cipher_name set to: "
"[%s]\n", cipher_name_dst);
cipher_name_set = 1;
break;
case ecryptfs_opt_ecryptfs_key_bytes:
cipher_key_bytes_src = args[0].from;
cipher_key_bytes =
(int)simple_strtol(cipher_key_bytes_src,
&cipher_key_bytes_src, 0);
mount_crypt_stat->global_default_cipher_key_size =
cipher_key_bytes;
ecryptfs_printk(KERN_DEBUG,
"The mount_crypt_stat "
"global_default_cipher_key_size "
"set to: [%d]\n", mount_crypt_stat->
global_default_cipher_key_size);
cipher_key_bytes_set = 1;
break;
case ecryptfs_opt_passthrough:
mount_crypt_stat->flags |=
ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
break;
[PATCH] eCryptfs: xattr flags and mount options This patch set introduces the ability to store cryptographic metadata into an lower file extended attribute rather than the lower file header region. This patch set implements two new mount options: ecryptfs_xattr_metadata - When set, newly created files will have their cryptographic metadata stored in the extended attribute region of the file rather than the header. When storing the data in the file header, there is a minimum of 8KB reserved for the header information for each file, making each file at least 12KB in size. This can take up a lot of extra disk space if the user creates a lot of small files. By storing the data in the extended attribute, each file will only occupy at least of 4KB of space. As the eCryptfs metadata set becomes larger with new features such as multi-key associations, most popular filesystems will not be able to store all of the information in the xattr region in some cases due to space constraints. However, the majority of users will only ever associate one key per file, so most users will be okay with storing their data in the xattr region. This option should be used with caution. I want to emphasize that the xattr must be maintained under all circumstances, or the file will be rendered permanently unrecoverable. The last thing I want is for a user to forget to set an xattr flag in a backup utility, only to later discover that their backups are worthless. ecryptfs_encrypted_view - When set, this option causes eCryptfs to present applications a view of encrypted files as if the cryptographic metadata were stored in the file header, whether the metadata is actually stored in the header or in the extended attributes. No matter what eCryptfs winds up doing in the lower filesystem, I want to preserve a baseline format compatibility for the encrypted files. As of right now, the metadata may be in the file header or in an xattr. There is no reason why the metadata could not be put in a separate file in future versions. Without the compatibility mode, backup utilities would have to know to back up the metadata file along with the files. The semantics of eCryptfs have always been that the lower files are self-contained units of encrypted data, and the only additional information required to decrypt any given eCryptfs file is the key. That is what has always been emphasized about eCryptfs lower files, and that is what users expect. Providing the encrypted view option will provide a way to userspace applications wherein they can always get to the same old familiar eCryptfs encrypted files, regardless of what eCryptfs winds up doing with the metadata behind the scenes. This patch: Add extended attribute support to version bit vector, flags to indicate when xattr or encrypted view modes are enabled, and support for the new mount options. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 03:53:45 -05:00
case ecryptfs_opt_xattr_metadata:
mount_crypt_stat->flags |=
ECRYPTFS_XATTR_METADATA_ENABLED;
break;
case ecryptfs_opt_encrypted_view:
mount_crypt_stat->flags |=
ECRYPTFS_XATTR_METADATA_ENABLED;
mount_crypt_stat->flags |=
ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
break;
case ecryptfs_opt_err:
default:
ecryptfs_printk(KERN_WARNING,
"eCryptfs: unrecognized option '%s'\n",
p);
}
}
if (!sig_set) {
rc = -EINVAL;
ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
"auth tok signature as a mount "
"parameter; see the eCryptfs README\n");
goto out;
}
if (!cipher_name_set) {
cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
if (unlikely(cipher_name_len
>= ECRYPTFS_MAX_CIPHER_NAME_SIZE)) {
rc = -EINVAL;
BUG();
goto out;
}
memcpy(mount_crypt_stat->global_default_cipher_name,
ECRYPTFS_DEFAULT_CIPHER, cipher_name_len);
mount_crypt_stat->global_default_cipher_name[cipher_name_len]
= '\0';
}
if (!cipher_key_bytes_set) {
mount_crypt_stat->global_default_cipher_key_size = 0;
}
if ((rc = ecryptfs_add_new_key_tfm(
NULL, mount_crypt_stat->global_default_cipher_name,
mount_crypt_stat->global_default_cipher_key_size))) {
printk(KERN_ERR "Error attempting to initialize cipher with "
"name = [%s] and key size = [%d]; rc = [%d]\n",
mount_crypt_stat->global_default_cipher_name,
mount_crypt_stat->global_default_cipher_key_size, rc);
rc = -EINVAL;
goto out;
}
if ((rc = ecryptfs_init_global_auth_toks(mount_crypt_stat))) {
printk(KERN_WARNING "One or more global auth toks could not "
"properly register; rc = [%d]\n", rc);
}
rc = 0;
out:
return rc;
}
struct kmem_cache *ecryptfs_sb_info_cache;
/**
* ecryptfs_fill_super
* @sb: The ecryptfs super block
* @raw_data: The options passed to mount
* @silent: Not used but required by function prototype
*
* Sets up what we can of the sb, rest is done in ecryptfs_read_super
*
* Returns zero on success; non-zero otherwise
*/
static int
ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
{
int rc = 0;
/* Released in ecryptfs_put_super() */
ecryptfs_set_superblock_private(sb,
kmem_cache_zalloc(ecryptfs_sb_info_cache,
GFP_KERNEL));
if (!ecryptfs_superblock_to_private(sb)) {
ecryptfs_printk(KERN_WARNING, "Out of memory\n");
rc = -ENOMEM;
goto out;
}
sb->s_op = &ecryptfs_sops;
/* Released through deactivate_super(sb) from get_sb_nodev */
sb->s_root = d_alloc(NULL, &(const struct qstr) {
.hash = 0,.name = "/",.len = 1});
if (!sb->s_root) {
ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
rc = -ENOMEM;
goto out;
}
sb->s_root->d_op = &ecryptfs_dops;
sb->s_root->d_sb = sb;
sb->s_root->d_parent = sb->s_root;
/* Released in d_release when dput(sb->s_root) is called */
/* through deactivate_super(sb) from get_sb_nodev() */
ecryptfs_set_dentry_private(sb->s_root,
kmem_cache_zalloc(ecryptfs_dentry_info_cache,
GFP_KERNEL));
if (!ecryptfs_dentry_to_private(sb->s_root)) {
ecryptfs_printk(KERN_ERR,
"dentry_info_cache alloc failed\n");
rc = -ENOMEM;
goto out;
}
rc = 0;
out:
/* Should be able to rely on deactivate_super called from
* get_sb_nodev */
return rc;
}
/**
* ecryptfs_read_super
* @sb: The ecryptfs super block
* @dev_name: The path to mount over
*
* Read the super block of the lower filesystem, and use
* ecryptfs_interpose to create our initial inode and super block
* struct.
*/
static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
{
int rc;
struct nameidata nd;
struct dentry *lower_root;
struct vfsmount *lower_mnt;
memset(&nd, 0, sizeof(struct nameidata));
rc = path_lookup(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &nd);
if (rc) {
ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
goto out;
}
lower_root = nd.dentry;
lower_mnt = nd.mnt;
ecryptfs_set_superblock_lower(sb, lower_root->d_sb);
sb->s_maxbytes = lower_root->d_sb->s_maxbytes;
ecryptfs_set_dentry_lower(sb->s_root, lower_root);
ecryptfs_set_dentry_lower_mnt(sb->s_root, lower_mnt);
if ((rc = ecryptfs_interpose(lower_root, sb->s_root, sb, 0)))
goto out_free;
rc = 0;
goto out;
out_free:
path_release(&nd);
out:
return rc;
}
/**
* ecryptfs_get_sb
* @fs_type
* @flags
* @dev_name: The path to mount over
* @raw_data: The options passed into the kernel
*
* The whole ecryptfs_get_sb process is broken into 4 functions:
* ecryptfs_parse_options(): handle options passed to ecryptfs, if any
* ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
* with as much information as it can before needing
* the lower filesystem.
* ecryptfs_read_super(): this accesses the lower filesystem and uses
* ecryptfs_interpolate to perform most of the linking
* ecryptfs_interpolate(): links the lower filesystem into ecryptfs
*/
static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *raw_data,
struct vfsmount *mnt)
{
int rc;
struct super_block *sb;
rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
if (rc < 0) {
printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
goto out;
}
sb = mnt->mnt_sb;
rc = ecryptfs_parse_options(sb, raw_data);
if (rc) {
printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
goto out_abort;
}
rc = ecryptfs_read_super(sb, dev_name);
if (rc) {
printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
goto out_abort;
}
goto out;
out_abort:
dput(sb->s_root);
up_write(&sb->s_umount);
deactivate_super(sb);
out:
return rc;
}
/**
* ecryptfs_kill_block_super
* @sb: The ecryptfs super block
*
* Used to bring the superblock down and free the private data.
* Private data is free'd in ecryptfs_put_super()
*/
static void ecryptfs_kill_block_super(struct super_block *sb)
{
generic_shutdown_super(sb);
}
static struct file_system_type ecryptfs_fs_type = {
.owner = THIS_MODULE,
.name = "ecryptfs",
.get_sb = ecryptfs_get_sb,
.kill_sb = ecryptfs_kill_block_super,
.fs_flags = 0
};
/**
* inode_info_init_once
*
* Initializes the ecryptfs_inode_info_cache when it is created
*/
static void
inode_info_init_once(void *vptr, struct kmem_cache *cachep, unsigned long flags)
{
struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
inode_init_once(&ei->vfs_inode);
}
static struct ecryptfs_cache_info {
struct kmem_cache **cache;
const char *name;
size_t size;
void (*ctor)(void*, struct kmem_cache *, unsigned long);
} ecryptfs_cache_infos[] = {
{
.cache = &ecryptfs_auth_tok_list_item_cache,
.name = "ecryptfs_auth_tok_list_item",
.size = sizeof(struct ecryptfs_auth_tok_list_item),
},
{
.cache = &ecryptfs_file_info_cache,
.name = "ecryptfs_file_cache",
.size = sizeof(struct ecryptfs_file_info),
},
{
.cache = &ecryptfs_dentry_info_cache,
.name = "ecryptfs_dentry_info_cache",
.size = sizeof(struct ecryptfs_dentry_info),
},
{
.cache = &ecryptfs_inode_info_cache,
.name = "ecryptfs_inode_cache",
.size = sizeof(struct ecryptfs_inode_info),
.ctor = inode_info_init_once,
},
{
.cache = &ecryptfs_sb_info_cache,
.name = "ecryptfs_sb_cache",
.size = sizeof(struct ecryptfs_sb_info),
},
{
.cache = &ecryptfs_header_cache_0,
.name = "ecryptfs_headers_0",
.size = PAGE_CACHE_SIZE,
},
{
.cache = &ecryptfs_header_cache_1,
.name = "ecryptfs_headers_1",
.size = PAGE_CACHE_SIZE,
},
{
.cache = &ecryptfs_header_cache_2,
.name = "ecryptfs_headers_2",
.size = PAGE_CACHE_SIZE,
},
{
.cache = &ecryptfs_xattr_cache,
.name = "ecryptfs_xattr_cache",
.size = PAGE_CACHE_SIZE,
},
{
.cache = &ecryptfs_lower_page_cache,
.name = "ecryptfs_lower_page_cache",
.size = PAGE_CACHE_SIZE,
},
{
.cache = &ecryptfs_key_record_cache,
.name = "ecryptfs_key_record_cache",
.size = sizeof(struct ecryptfs_key_record),
},
{
.cache = &ecryptfs_key_sig_cache,
.name = "ecryptfs_key_sig_cache",
.size = sizeof(struct ecryptfs_key_sig),
},
{
.cache = &ecryptfs_global_auth_tok_cache,
.name = "ecryptfs_global_auth_tok_cache",
.size = sizeof(struct ecryptfs_global_auth_tok),
},
{
.cache = &ecryptfs_key_tfm_cache,
.name = "ecryptfs_key_tfm_cache",
.size = sizeof(struct ecryptfs_key_tfm),
},
};
static void ecryptfs_free_kmem_caches(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
struct ecryptfs_cache_info *info;
info = &ecryptfs_cache_infos[i];
if (*(info->cache))
kmem_cache_destroy(*(info->cache));
}
}
/**
* ecryptfs_init_kmem_caches
*
* Returns zero on success; non-zero otherwise
*/
static int ecryptfs_init_kmem_caches(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
struct ecryptfs_cache_info *info;
info = &ecryptfs_cache_infos[i];
*(info->cache) = kmem_cache_create(info->name, info->size,
0, SLAB_HWCACHE_ALIGN, info->ctor);
if (!*(info->cache)) {
ecryptfs_free_kmem_caches();
ecryptfs_printk(KERN_WARNING, "%s: "
"kmem_cache_create failed\n",
info->name);
return -ENOMEM;
}
}
return 0;
}
struct ecryptfs_obj {
char *name;
struct list_head slot_list;
struct kobject kobj;
};
struct ecryptfs_attribute {
struct attribute attr;
ssize_t(*show) (struct ecryptfs_obj *, char *);
ssize_t(*store) (struct ecryptfs_obj *, const char *, size_t);
};
static ssize_t
ecryptfs_attr_store(struct kobject *kobj,
struct attribute *attr, const char *buf, size_t len)
{
struct ecryptfs_obj *obj = container_of(kobj, struct ecryptfs_obj,
kobj);
struct ecryptfs_attribute *attribute =
container_of(attr, struct ecryptfs_attribute, attr);
return (attribute->store ? attribute->store(obj, buf, len) : 0);
}
static ssize_t
ecryptfs_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
{
struct ecryptfs_obj *obj = container_of(kobj, struct ecryptfs_obj,
kobj);
struct ecryptfs_attribute *attribute =
container_of(attr, struct ecryptfs_attribute, attr);
return (attribute->show ? attribute->show(obj, buf) : 0);
}
static struct sysfs_ops ecryptfs_sysfs_ops = {
.show = ecryptfs_attr_show,
.store = ecryptfs_attr_store
};
static struct kobj_type ecryptfs_ktype = {
.sysfs_ops = &ecryptfs_sysfs_ops
};
static decl_subsys(ecryptfs, &ecryptfs_ktype, NULL);
static ssize_t version_show(struct ecryptfs_obj *obj, char *buff)
{
return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
}
static struct ecryptfs_attribute sysfs_attr_version = __ATTR_RO(version);
static struct ecryptfs_version_str_map_elem {
u32 flag;
char *str;
} ecryptfs_version_str_map[] = {
{ECRYPTFS_VERSIONING_PASSPHRASE, "passphrase"},
{ECRYPTFS_VERSIONING_PUBKEY, "pubkey"},
{ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH, "plaintext passthrough"},
[PATCH] eCryptfs: xattr flags and mount options This patch set introduces the ability to store cryptographic metadata into an lower file extended attribute rather than the lower file header region. This patch set implements two new mount options: ecryptfs_xattr_metadata - When set, newly created files will have their cryptographic metadata stored in the extended attribute region of the file rather than the header. When storing the data in the file header, there is a minimum of 8KB reserved for the header information for each file, making each file at least 12KB in size. This can take up a lot of extra disk space if the user creates a lot of small files. By storing the data in the extended attribute, each file will only occupy at least of 4KB of space. As the eCryptfs metadata set becomes larger with new features such as multi-key associations, most popular filesystems will not be able to store all of the information in the xattr region in some cases due to space constraints. However, the majority of users will only ever associate one key per file, so most users will be okay with storing their data in the xattr region. This option should be used with caution. I want to emphasize that the xattr must be maintained under all circumstances, or the file will be rendered permanently unrecoverable. The last thing I want is for a user to forget to set an xattr flag in a backup utility, only to later discover that their backups are worthless. ecryptfs_encrypted_view - When set, this option causes eCryptfs to present applications a view of encrypted files as if the cryptographic metadata were stored in the file header, whether the metadata is actually stored in the header or in the extended attributes. No matter what eCryptfs winds up doing in the lower filesystem, I want to preserve a baseline format compatibility for the encrypted files. As of right now, the metadata may be in the file header or in an xattr. There is no reason why the metadata could not be put in a separate file in future versions. Without the compatibility mode, backup utilities would have to know to back up the metadata file along with the files. The semantics of eCryptfs have always been that the lower files are self-contained units of encrypted data, and the only additional information required to decrypt any given eCryptfs file is the key. That is what has always been emphasized about eCryptfs lower files, and that is what users expect. Providing the encrypted view option will provide a way to userspace applications wherein they can always get to the same old familiar eCryptfs encrypted files, regardless of what eCryptfs winds up doing with the metadata behind the scenes. This patch: Add extended attribute support to version bit vector, flags to indicate when xattr or encrypted view modes are enabled, and support for the new mount options. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 03:53:45 -05:00
{ECRYPTFS_VERSIONING_POLICY, "policy"},
{ECRYPTFS_VERSIONING_XATTR, "metadata in extended attribute"},
{ECRYPTFS_VERSIONING_MULTKEY, "multiple keys per file"}
};
static ssize_t version_str_show(struct ecryptfs_obj *obj, char *buff)
{
int i;
int remaining = PAGE_SIZE;
int total_written = 0;
buff[0] = '\0';
for (i = 0; i < ARRAY_SIZE(ecryptfs_version_str_map); i++) {
int entry_size;
if (!(ECRYPTFS_VERSIONING_MASK
& ecryptfs_version_str_map[i].flag))
continue;
entry_size = strlen(ecryptfs_version_str_map[i].str);
if ((entry_size + 2) > remaining)
goto out;
memcpy(buff, ecryptfs_version_str_map[i].str, entry_size);
buff[entry_size++] = '\n';
buff[entry_size] = '\0';
buff += entry_size;
total_written += entry_size;
remaining -= entry_size;
}
out:
return total_written;
}
static struct ecryptfs_attribute sysfs_attr_version_str = __ATTR_RO(version_str);
static int do_sysfs_registration(void)
{
int rc;
if ((rc = subsystem_register(&ecryptfs_subsys))) {
printk(KERN_ERR
"Unable to register ecryptfs sysfs subsystem\n");
goto out;
}
rc = sysfs_create_file(&ecryptfs_subsys.kobj,
&sysfs_attr_version.attr);
if (rc) {
printk(KERN_ERR
"Unable to create ecryptfs version attribute\n");
subsystem_unregister(&ecryptfs_subsys);
goto out;
}
rc = sysfs_create_file(&ecryptfs_subsys.kobj,
&sysfs_attr_version_str.attr);
if (rc) {
printk(KERN_ERR
"Unable to create ecryptfs version_str attribute\n");
sysfs_remove_file(&ecryptfs_subsys.kobj,
&sysfs_attr_version.attr);
subsystem_unregister(&ecryptfs_subsys);
goto out;
}
out:
return rc;
}
static void do_sysfs_unregistration(void)
{
int rc;
if ((rc = ecryptfs_destruct_crypto())) {
printk(KERN_ERR "Failure whilst attempting to destruct crypto; "
"rc = [%d]\n", rc);
}
sysfs_remove_file(&ecryptfs_subsys.kobj,
&sysfs_attr_version.attr);
sysfs_remove_file(&ecryptfs_subsys.kobj,
&sysfs_attr_version_str.attr);
subsystem_unregister(&ecryptfs_subsys);
}
static int __init ecryptfs_init(void)
{
int rc;
if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
rc = -EINVAL;
ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
"larger than the host's page size, and so "
"eCryptfs cannot run on this system. The "
"default eCryptfs extent size is [%d] bytes; "
"the page size is [%d] bytes.\n",
ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
goto out;
}
rc = ecryptfs_init_kmem_caches();
if (rc) {
printk(KERN_ERR
"Failed to allocate one or more kmem_cache objects\n");
goto out;
}
rc = register_filesystem(&ecryptfs_fs_type);
if (rc) {
printk(KERN_ERR "Failed to register filesystem\n");
ecryptfs_free_kmem_caches();
goto out;
}
kobj_set_kset_s(&ecryptfs_subsys, fs_subsys);
rc = do_sysfs_registration();
if (rc) {
printk(KERN_ERR "sysfs registration failed\n");
unregister_filesystem(&ecryptfs_fs_type);
ecryptfs_free_kmem_caches();
goto out;
}
rc = ecryptfs_init_messaging(ecryptfs_transport);
if (rc) {
ecryptfs_printk(KERN_ERR, "Failure occured while attempting to "
"initialize the eCryptfs netlink socket\n");
do_sysfs_unregistration();
unregister_filesystem(&ecryptfs_fs_type);
ecryptfs_free_kmem_caches();
goto out;
}
rc = ecryptfs_init_crypto();
if (rc) {
printk(KERN_ERR "Failure whilst attempting to init crypto; "
"rc = [%d]\n", rc);
do_sysfs_unregistration();
unregister_filesystem(&ecryptfs_fs_type);
ecryptfs_free_kmem_caches();
goto out;
}
out:
return rc;
}
static void __exit ecryptfs_exit(void)
{
do_sysfs_unregistration();
ecryptfs_release_messaging(ecryptfs_transport);
unregister_filesystem(&ecryptfs_fs_type);
ecryptfs_free_kmem_caches();
}
MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
MODULE_DESCRIPTION("eCryptfs");
MODULE_LICENSE("GPL");
module_init(ecryptfs_init)
module_exit(ecryptfs_exit)