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linux-next/fs/ecryptfs/main.c
Eric W. Biederman 7f78e03513 fs: Limit sys_mount to only request filesystem modules. 
Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.

A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.

Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.

Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives.  Allowing simple, safe,
well understood work-arounds to known problematic software.

This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work.  While writing this patch I saw a handful of such
cases.  The most significant being autofs that lives in the module
autofs4.

This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.

After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module.  The common pattern in the kernel is to call request_module()
without regards to the users permissions.  In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted.  In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-03 19:36:31 -08:00

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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/mount.h>
#include <linux/pagemap.h>
#include <linux/key.h>
#include <linux/parser.h>
#include <linux/fs_stack.h>
#include <linux/slab.h>
#include <linux/magic.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 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 from ecryptfsd. The actual sleep time will be, more than
* likely, a small amount greater than this specified value, but only less if
* the 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");
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_init_lower_file
* @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
* the lower dentry and the lower mount set
*
* eCryptfs only ever keeps a single open file for every lower
* inode. All I/O operations to the lower inode occur through that
* file. When the first eCryptfs dentry that interposes with the first
* lower dentry for that inode is created, this function creates the
* lower file struct and associates it with the eCryptfs
* inode. When all eCryptfs files associated with the inode are released, the
* file is closed.
*
* The lower file will be opened with read/write permissions, if
* possible. Otherwise, it is opened read-only.
*
* This function does nothing if a lower file is already
* associated with the eCryptfs inode.
*
* Returns zero on success; non-zero otherwise
*/
static int ecryptfs_init_lower_file(struct dentry *dentry,
struct file **lower_file)
{
const struct cred *cred = current_cred();
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
int rc;
rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
cred);
if (rc) {
printk(KERN_ERR "Error opening lower file "
"for lower_dentry [0x%p] and lower_mnt [0x%p]; "
"rc = [%d]\n", lower_dentry, lower_mnt, rc);
(*lower_file) = NULL;
}
return rc;
}
int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
{
struct ecryptfs_inode_info *inode_info;
int count, rc = 0;
inode_info = ecryptfs_inode_to_private(inode);
mutex_lock(&inode_info->lower_file_mutex);
count = atomic_inc_return(&inode_info->lower_file_count);
if (WARN_ON_ONCE(count < 1))
rc = -EINVAL;
else if (count == 1) {
rc = ecryptfs_init_lower_file(dentry,
&inode_info->lower_file);
if (rc)
atomic_set(&inode_info->lower_file_count, 0);
}
mutex_unlock(&inode_info->lower_file_mutex);
return rc;
}
void ecryptfs_put_lower_file(struct inode *inode)
{
struct ecryptfs_inode_info *inode_info;
inode_info = ecryptfs_inode_to_private(inode);
if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
&inode_info->lower_file_mutex)) {
filemap_write_and_wait(inode->i_mapping);
fput(inode_info->lower_file);
inode_info->lower_file = NULL;
mutex_unlock(&inode_info->lower_file_mutex);
}
}
enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
ecryptfs_opt_ecryptfs_key_bytes,
ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
ecryptfs_opt_check_dev_ruid,
ecryptfs_opt_err };
static const match_table_t tokens = {
{ecryptfs_opt_sig, "sig=%s"},
{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
{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"},
{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
{ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
{ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
{ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
{ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
{ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
{ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
{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;
struct ecryptfs_auth_tok *auth_tok;
int rc = 0;
list_for_each_entry(global_auth_tok,
&mount_crypt_stat->global_auth_tok_list,
mount_crypt_stat_list) {
rc = ecryptfs_keyring_auth_tok_for_sig(
&global_auth_tok->global_auth_tok_key, &auth_tok,
global_auth_tok->sig);
if (rc) {
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;
goto out;
} else {
global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
up_write(&(global_auth_tok->global_auth_tok_key)->sem);
}
}
out:
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 passed to the kernel
* @check_ruid: set to 1 if device uid should be checked against the ruid
*
* 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 ecryptfs_sb_info *sbi, char *options,
uid_t *check_ruid)
{
char *p;
int rc = 0;
int sig_set = 0;
int cipher_name_set = 0;
int fn_cipher_name_set = 0;
int cipher_key_bytes;
int cipher_key_bytes_set = 0;
int fn_cipher_key_bytes;
int fn_cipher_key_bytes_set = 0;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
&sbi->mount_crypt_stat;
substring_t args[MAX_OPT_ARGS];
int token;
char *sig_src;
char *cipher_name_dst;
char *cipher_name_src;
char *fn_cipher_name_dst;
char *fn_cipher_name_src;
char *fnek_dst;
char *fnek_src;
char *cipher_key_bytes_src;
char *fn_cipher_key_bytes_src;
u8 cipher_code;
*check_ruid = 0;
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, 0);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global sig; rc = [%d]\n", rc);
goto out;
}
sig_set = 1;
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);
cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
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;
cipher_key_bytes_set = 1;
break;
case ecryptfs_opt_passthrough:
mount_crypt_stat->flags |=
ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
break;
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_fnek_sig:
fnek_src = args[0].from;
fnek_dst =
mount_crypt_stat->global_default_fnek_sig;
strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
mount_crypt_stat->global_default_fnek_sig[
ECRYPTFS_SIG_SIZE_HEX] = '\0';
rc = ecryptfs_add_global_auth_tok(
mount_crypt_stat,
mount_crypt_stat->global_default_fnek_sig,
ECRYPTFS_AUTH_TOK_FNEK);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global fnek sig [%s]; rc = [%d]\n",
mount_crypt_stat->global_default_fnek_sig,
rc);
goto out;
}
mount_crypt_stat->flags |=
(ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
| ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
break;
case ecryptfs_opt_fn_cipher:
fn_cipher_name_src = args[0].from;
fn_cipher_name_dst =
mount_crypt_stat->global_default_fn_cipher_name;
strncpy(fn_cipher_name_dst, fn_cipher_name_src,
ECRYPTFS_MAX_CIPHER_NAME_SIZE);
mount_crypt_stat->global_default_fn_cipher_name[
ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
fn_cipher_name_set = 1;
break;
case ecryptfs_opt_fn_cipher_key_bytes:
fn_cipher_key_bytes_src = args[0].from;
fn_cipher_key_bytes =
(int)simple_strtol(fn_cipher_key_bytes_src,
&fn_cipher_key_bytes_src, 0);
mount_crypt_stat->global_default_fn_cipher_key_bytes =
fn_cipher_key_bytes;
fn_cipher_key_bytes_set = 1;
break;
case ecryptfs_opt_unlink_sigs:
mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
break;
case ecryptfs_opt_mount_auth_tok_only:
mount_crypt_stat->flags |=
ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
break;
case ecryptfs_opt_check_dev_ruid:
*check_ruid = 1;
break;
case ecryptfs_opt_err:
default:
printk(KERN_WARNING
"%s: eCryptfs: unrecognized option [%s]\n",
__func__, 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) {
int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
strcpy(mount_crypt_stat->global_default_cipher_name,
ECRYPTFS_DEFAULT_CIPHER);
}
if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
&& !fn_cipher_name_set)
strcpy(mount_crypt_stat->global_default_fn_cipher_name,
mount_crypt_stat->global_default_cipher_name);
if (!cipher_key_bytes_set)
mount_crypt_stat->global_default_cipher_key_size = 0;
if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
&& !fn_cipher_key_bytes_set)
mount_crypt_stat->global_default_fn_cipher_key_bytes =
mount_crypt_stat->global_default_cipher_key_size;
cipher_code = ecryptfs_code_for_cipher_string(
mount_crypt_stat->global_default_cipher_name,
mount_crypt_stat->global_default_cipher_key_size);
if (!cipher_code) {
ecryptfs_printk(KERN_ERR,
"eCryptfs doesn't support cipher: %s",
mount_crypt_stat->global_default_cipher_name);
rc = -EINVAL;
goto out;
}
mutex_lock(&key_tfm_list_mutex);
if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
NULL)) {
rc = ecryptfs_add_new_key_tfm(
NULL, mount_crypt_stat->global_default_cipher_name,
mount_crypt_stat->global_default_cipher_key_size);
if (rc) {
printk(KERN_ERR "Error attempting to initialize "
"cipher with name = [%s] and key size = [%td]; "
"rc = [%d]\n",
mount_crypt_stat->global_default_cipher_name,
mount_crypt_stat->global_default_cipher_key_size,
rc);
rc = -EINVAL;
mutex_unlock(&key_tfm_list_mutex);
goto out;
}
}
if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
&& !ecryptfs_tfm_exists(
mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
rc = ecryptfs_add_new_key_tfm(
NULL, mount_crypt_stat->global_default_fn_cipher_name,
mount_crypt_stat->global_default_fn_cipher_key_bytes);
if (rc) {
printk(KERN_ERR "Error attempting to initialize "
"cipher with name = [%s] and key size = [%td]; "
"rc = [%d]\n",
mount_crypt_stat->global_default_fn_cipher_name,
mount_crypt_stat->global_default_fn_cipher_key_bytes,
rc);
rc = -EINVAL;
mutex_unlock(&key_tfm_list_mutex);
goto out;
}
}
mutex_unlock(&key_tfm_list_mutex);
rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
if (rc)
printk(KERN_WARNING "One or more global auth toks could not "
"properly register; rc = [%d]\n", rc);
out:
return rc;
}
struct kmem_cache *ecryptfs_sb_info_cache;
static struct file_system_type ecryptfs_fs_type;
/**
* ecryptfs_get_sb
* @fs_type
* @flags
* @dev_name: The path to mount over
* @raw_data: The options passed into the kernel
*/
static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *raw_data)
{
struct super_block *s;
struct ecryptfs_sb_info *sbi;
struct ecryptfs_dentry_info *root_info;
const char *err = "Getting sb failed";
struct inode *inode;
struct path path;
uid_t check_ruid;
int rc;
sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
if (!sbi) {
rc = -ENOMEM;
goto out;
}
rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
if (rc) {
err = "Error parsing options";
goto out;
}
s = sget(fs_type, NULL, set_anon_super, flags, NULL);
if (IS_ERR(s)) {
rc = PTR_ERR(s);
goto out;
}
rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
if (rc)
goto out1;
ecryptfs_set_superblock_private(s, sbi);
s->s_bdi = &sbi->bdi;
/* ->kill_sb() will take care of sbi after that point */
sbi = NULL;
s->s_op = &ecryptfs_sops;
s->s_d_op = &ecryptfs_dops;
err = "Reading sb failed";
rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
if (rc) {
ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
goto out1;
}
if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
rc = -EINVAL;
printk(KERN_ERR "Mount on filesystem of type "
"eCryptfs explicitly disallowed due to "
"known incompatibilities\n");
goto out_free;
}
if (check_ruid && !uid_eq(path.dentry->d_inode->i_uid, current_uid())) {
rc = -EPERM;
printk(KERN_ERR "Mount of device (uid: %d) not owned by "
"requested user (uid: %d)\n",
i_uid_read(path.dentry->d_inode),
from_kuid(&init_user_ns, current_uid()));
goto out_free;
}
ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
/**
* Set the POSIX ACL flag based on whether they're enabled in the lower
* mount. Force a read-only eCryptfs mount if the lower mount is ro.
* Allow a ro eCryptfs mount even when the lower mount is rw.
*/
s->s_flags = flags & ~MS_POSIXACL;
s->s_flags |= path.dentry->d_sb->s_flags & (MS_RDONLY | MS_POSIXACL);
s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
s->s_blocksize = path.dentry->d_sb->s_blocksize;
s->s_magic = ECRYPTFS_SUPER_MAGIC;
inode = ecryptfs_get_inode(path.dentry->d_inode, s);
rc = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_free;
s->s_root = d_make_root(inode);
if (!s->s_root) {
rc = -ENOMEM;
goto out_free;
}
rc = -ENOMEM;
root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
if (!root_info)
goto out_free;
/* ->kill_sb() will take care of root_info */
ecryptfs_set_dentry_private(s->s_root, root_info);
ecryptfs_set_dentry_lower(s->s_root, path.dentry);
ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
s->s_flags |= MS_ACTIVE;
return dget(s->s_root);
out_free:
path_put(&path);
out1:
deactivate_locked_super(s);
out:
if (sbi) {
ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
kmem_cache_free(ecryptfs_sb_info_cache, sbi);
}
printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
return ERR_PTR(rc);
}
/**
* ecryptfs_kill_block_super
* @sb: The ecryptfs super block
*
* Used to bring the superblock down and free the private data.
*/
static void ecryptfs_kill_block_super(struct super_block *sb)
{
struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
kill_anon_super(sb);
if (!sb_info)
return;
ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
bdi_destroy(&sb_info->bdi);
kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
}
static struct file_system_type ecryptfs_fs_type = {
.owner = THIS_MODULE,
.name = "ecryptfs",
.mount = ecryptfs_mount,
.kill_sb = ecryptfs_kill_block_super,
.fs_flags = 0
};
MODULE_ALIAS_FS("ecryptfs");
/**
* inode_info_init_once
*
* Initializes the ecryptfs_inode_info_cache when it is created
*/
static void
inode_info_init_once(void *vptr)
{
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 *obj);
} 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,
.name = "ecryptfs_headers",
.size = PAGE_CACHE_SIZE,
},
{
.cache = &ecryptfs_xattr_cache,
.name = "ecryptfs_xattr_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;
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
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;
}
static struct kobject *ecryptfs_kobj;
static ssize_t version_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buff)
{
return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
}
static struct kobj_attribute version_attr = __ATTR_RO(version);
static struct attribute *attributes[] = {
&version_attr.attr,
NULL,
};
static struct attribute_group attr_group = {
.attrs = attributes,
};
static int do_sysfs_registration(void)
{
int rc;
ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
if (!ecryptfs_kobj) {
printk(KERN_ERR "Unable to create ecryptfs kset\n");
rc = -ENOMEM;
goto out;
}
rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
if (rc) {
printk(KERN_ERR
"Unable to create ecryptfs version attributes\n");
kobject_put(ecryptfs_kobj);
}
out:
return rc;
}
static void do_sysfs_unregistration(void)
{
sysfs_remove_group(ecryptfs_kobj, &attr_group);
kobject_put(ecryptfs_kobj);
}
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 [%u] bytes; "
"the page size is [%lu] bytes.\n",
ECRYPTFS_DEFAULT_EXTENT_SIZE,
(unsigned long)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 = do_sysfs_registration();
if (rc) {
printk(KERN_ERR "sysfs registration failed\n");
goto out_free_kmem_caches;
}
rc = ecryptfs_init_kthread();
if (rc) {
printk(KERN_ERR "%s: kthread initialization failed; "
"rc = [%d]\n", __func__, rc);
goto out_do_sysfs_unregistration;
}
rc = ecryptfs_init_messaging();
if (rc) {
printk(KERN_ERR "Failure occurred while attempting to "
"initialize the communications channel to "
"ecryptfsd\n");
goto out_destroy_kthread;
}
rc = ecryptfs_init_crypto();
if (rc) {
printk(KERN_ERR "Failure whilst attempting to init crypto; "
"rc = [%d]\n", rc);
goto out_release_messaging;
}
rc = register_filesystem(&ecryptfs_fs_type);
if (rc) {
printk(KERN_ERR "Failed to register filesystem\n");
goto out_destroy_crypto;
}
if (ecryptfs_verbosity > 0)
printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
"will be written to the syslog!\n", ecryptfs_verbosity);
goto out;
out_destroy_crypto:
ecryptfs_destroy_crypto();
out_release_messaging:
ecryptfs_release_messaging();
out_destroy_kthread:
ecryptfs_destroy_kthread();
out_do_sysfs_unregistration:
do_sysfs_unregistration();
out_free_kmem_caches:
ecryptfs_free_kmem_caches();
out:
return rc;
}
static void __exit ecryptfs_exit(void)
{
int rc;
rc = ecryptfs_destroy_crypto();
if (rc)
printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
"rc = [%d]\n", rc);
ecryptfs_release_messaging();
ecryptfs_destroy_kthread();
do_sysfs_unregistration();
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)
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