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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/ecryptfs/main.c

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24 KiB
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,
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"},
{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
{ecryptfs_opt_err, NULL}
};
/**
* ecryptfs_verify_version
* @version: The version number to confirm
*
* Returns zero on good version; non-zero otherwise
*/
static int ecryptfs_verify_version(u16 version)
{
int rc = 0;
unsigned char major;
unsigned char minor;
major = ((version >> 8) & 0xFF);
minor = (version & 0xFF);
if (major != ECRYPTFS_VERSION_MAJOR) {
ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
"Expected [%d]; got [%d]\n",
ECRYPTFS_VERSION_MAJOR, major);
rc = -EINVAL;
goto out;
}
if (minor != ECRYPTFS_VERSION_MINOR) {
ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
"Expected [%d]; got [%d]\n",
ECRYPTFS_VERSION_MINOR, minor);
rc = -EINVAL;
goto out;
}
out:
return rc;
}
/**
* 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 key *auth_tok_key = NULL;
struct ecryptfs_auth_tok *auth_tok = NULL;
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 *sig_dst;
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;
}
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;
sig_dst =
mount_crypt_stat->global_auth_tok_sig;
memcpy(sig_dst, sig_src, ECRYPTFS_SIG_SIZE_HEX);
sig_dst[ECRYPTFS_SIG_SIZE_HEX] = '\0';
ecryptfs_printk(KERN_DEBUG,
"The mount_crypt_stat "
"global_auth_tok_sig set to: "
"[%s]\n", sig_dst);
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;
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);
}
}
/* Do not support lack of mount-wide signature in 0.1
* release */
if (!sig_set) {
rc = -EINVAL;
ecryptfs_printk(KERN_ERR, "You must supply a valid "
"passphrase 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;
}
rc = ecryptfs_process_cipher(
&mount_crypt_stat->global_key_tfm,
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 [%s] "
"with key size [%Zd] bytes; rc = [%d]\n",
mount_crypt_stat->global_default_cipher_name,
mount_crypt_stat->global_default_cipher_key_size, rc);
mount_crypt_stat->global_key_tfm = NULL;
mount_crypt_stat->global_auth_tok_key = NULL;
rc = -EINVAL;
goto out;
}
mutex_init(&mount_crypt_stat->global_key_tfm_mutex);
ecryptfs_printk(KERN_DEBUG, "Requesting the key with description: "
"[%s]\n", mount_crypt_stat->global_auth_tok_sig);
/* The reference to this key is held until umount is done The
* call to key_put is done in ecryptfs_put_super() */
auth_tok_key = request_key(&key_type_user,
mount_crypt_stat->global_auth_tok_sig,
NULL);
if (!auth_tok_key || IS_ERR(auth_tok_key)) {
ecryptfs_printk(KERN_ERR, "Could not find key with "
"description: [%s]\n",
mount_crypt_stat->global_auth_tok_sig);
process_request_key_err(PTR_ERR(auth_tok_key));
rc = -EINVAL;
goto out;
}
auth_tok = ecryptfs_get_key_payload_data(auth_tok_key);
if (ecryptfs_verify_version(auth_tok->version)) {
ecryptfs_printk(KERN_ERR, "Data structure version mismatch. "
"Userspace tools must match eCryptfs kernel "
"module with major version [%d] and minor "
"version [%d]\n", ECRYPTFS_VERSION_MAJOR,
ECRYPTFS_VERSION_MINOR);
rc = -EINVAL;
goto out;
}
if (auth_tok->token_type != ECRYPTFS_PASSWORD
&& auth_tok->token_type != ECRYPTFS_PRIVATE_KEY) {
ecryptfs_printk(KERN_ERR, "Invalid auth_tok structure "
"returned from key query\n");
rc = -EINVAL;
goto out;
}
mount_crypt_stat->global_auth_tok_key = auth_tok_key;
mount_crypt_stat->global_auth_tok = auth_tok;
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),
},
};
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, NULL);
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"},
{ECRYPTFS_VERSIONING_POLICY, "policy"},
{ECRYPTFS_VERSIONING_XATTR, "metadata in extended attribute"}
};
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 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);
sysfs_attr_version.attr.owner = THIS_MODULE;
sysfs_attr_version_str.attr.owner = THIS_MODULE;
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");
}
out:
return rc;
}
static void __exit ecryptfs_exit(void)
{
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);
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)
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