main.c

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#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"

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)");

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");

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");

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);
}

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;
}

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;

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);

    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);
}

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
};

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));
    }
}

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 <[email protected]>");
MODULE_DESCRIPTION("eCryptfs");

MODULE_LICENSE("GPL");

module_init(ecryptfs_init)
module_exit(ecryptfs_exit)