[PATCH] ecryptfs: fs/Makefile and fs/Kconfig

eCryptfs is a stacked cryptographic filesystem for Linux.  It is derived from
Erez Zadok's Cryptfs, implemented through the FiST framework for generating
stacked filesystems.  eCryptfs extends Cryptfs to provide advanced key
management and policy features.  eCryptfs stores cryptographic metadata in the
header of each file written, so that encrypted files can be copied between
hosts; the file will be decryptable with the proper key, and there is no need
to keep track of any additional information aside from what is already in the
encrypted file itself.

[akpm@osdl.org: updates for ongoing API changes]
[bunk@stusta.de: cleanups]
[akpm@osdl.org: alpha build fix]
[akpm@osdl.org: cleanups]
[tytso@mit.edu: inode-diet updates]
[pbadari@us.ibm.com: generic_file_*_read/write() interface updates]
[rdunlap@xenotime.net: printk format fixes]
[akpm@osdl.org: make slab creation and teardown table-driven]
Signed-off-by: Phillip Hellewell <phillip@hellewell.homeip.net>
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 831 insertions, 0 deletions

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
new file mode 100644
index 0000000..7a11b8a
--- /dev/null
+++ b/fs/ecryptfs/main.c
@@ -0,0 +1,831 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Michael C. Thompson <mcthomps@us.ibm.com>
+ *
+ * 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 "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)");
+
+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;
+	/* TODO: Is there a better way to identify if the inode is
+	 * special? */
+	if (S_ISBLK(lower_inode->i_mode) || S_ISCHR(lower_inode->i_mode) ||
+	    S_ISFIFO(lower_inode->i_mode) || S_ISSOCK(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);
+	ecryptfs_copy_attr_all(inode, lower_inode);
+	/* This size will be overwritten for real files w/ headers and
+	 * other metadata */
+	ecryptfs_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_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_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;
+	struct crypto_tfm *tmp_tfm;
+	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_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 =
+			ECRYPTFS_DEFAULT_KEY_BYTES;
+		ecryptfs_printk(KERN_DEBUG, "Cipher key size was not "
+				"specified.  Defaulting to [%d]\n",
+				mount_crypt_stat->
+				global_default_cipher_key_size);
+	}
+	rc = ecryptfs_process_cipher(
+		&tmp_tfm,
+		&mount_crypt_stat->global_key_tfm,
+		mount_crypt_stat->global_default_cipher_name,
+		mount_crypt_stat->global_default_cipher_key_size);
+	if (tmp_tfm)
+		crypto_free_tfm(tmp_tfm);
+	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);
+		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) {
+		ecryptfs_printk(KERN_ERR, "Invalid auth_tok structure "
+				"returned from key\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_alloc(ecryptfs_sb_info_cache,
+							 SLAB_KERNEL));
+	if (!ecryptfs_superblock_to_private(sb)) {
+		ecryptfs_printk(KERN_WARNING, "Out of memory\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	memset(ecryptfs_superblock_to_private(sb), 0,
+	       sizeof(struct ecryptfs_sb_info));
+	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_alloc(ecryptfs_dentry_info_cache,
+						     SLAB_KERNEL));
+	if (!ecryptfs_dentry_to_private(sb->s_root)) {
+		ecryptfs_printk(KERN_ERR,
+				"dentry_info_cache alloc failed\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	memset(ecryptfs_dentry_to_private(sb->s_root), 0,
+	       sizeof(struct ecryptfs_dentry_info));
+	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, &nd);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
+		goto out_free;
+	}
+	lower_root = nd.dentry;
+	if (!lower_root->d_inode) {
+		ecryptfs_printk(KERN_WARNING,
+				"No directory to interpose on\n");
+		rc = -ENOENT;
+		goto out_free;
+	}
+	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;
+
+	if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
+	    SLAB_CTOR_CONSTRUCTOR)
+		inode_init_once(&ei->vfs_inode);
+}
+
+static struct ecryptfs_cache_info {
+	kmem_cache_t **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_lower_page_cache,
+		.name = "ecryptfs_lower_page_cache",
+		.size = PAGE_CACHE_SIZE,
+	},
+};
+
+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);
+
+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"}
+};
+
+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.kset.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.kset.kobj,
+			       &sysfs_attr_version_str.attr);
+	if (rc) {
+		printk(KERN_ERR
+		       "Unable to create ecryptfs version_str attribute\n");
+		sysfs_remove_file(&ecryptfs_subsys.kset.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;
+	}
+	kset_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;
+	}
+out:
+	return rc;
+}
+
+static void __exit ecryptfs_exit(void)
+{
+	sysfs_remove_file(&ecryptfs_subsys.kset.kobj,
+			  &sysfs_attr_version.attr);
+	sysfs_remove_file(&ecryptfs_subsys.kset.kobj,
+			  &sysfs_attr_version_str.attr);
+	subsystem_unregister(&ecryptfs_subsys);
+	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)