diff options
Diffstat (limited to 'fs/ecryptfs/inode.c')
| -rw-r--r-- | fs/ecryptfs/inode.c | 1079 |
1 files changed, 1079 insertions, 0 deletions
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c new file mode 100644 index 000000000000..efdd2b7b62d7 --- /dev/null +++ b/fs/ecryptfs/inode.c @@ -0,0 +1,1079 @@ +/** + * eCryptfs: Linux filesystem encryption layer + * + * Copyright (C) 1997-2004 Erez Zadok + * Copyright (C) 2001-2004 Stony Brook University + * Copyright (C) 2004-2006 International Business Machines Corp. + * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> + * Michael C. Thompsion <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/file.h> +#include <linux/vmalloc.h> +#include <linux/pagemap.h> +#include <linux/dcache.h> +#include <linux/namei.h> +#include <linux/mount.h> +#include <linux/crypto.h> +#include "ecryptfs_kernel.h" + +static struct dentry *lock_parent(struct dentry *dentry) +{ + struct dentry *dir; + + dir = dget(dentry->d_parent); + mutex_lock(&(dir->d_inode->i_mutex)); + return dir; +} + +static void unlock_parent(struct dentry *dentry) +{ + mutex_unlock(&(dentry->d_parent->d_inode->i_mutex)); + dput(dentry->d_parent); +} + +static void unlock_dir(struct dentry *dir) +{ + mutex_unlock(&dir->d_inode->i_mutex); + dput(dir); +} + +void ecryptfs_copy_inode_size(struct inode *dst, const struct inode *src) +{ + i_size_write(dst, i_size_read((struct inode *)src)); + dst->i_blocks = src->i_blocks; +} + +void ecryptfs_copy_attr_atime(struct inode *dest, const struct inode *src) +{ + dest->i_atime = src->i_atime; +} + +static void ecryptfs_copy_attr_times(struct inode *dest, + const struct inode *src) +{ + dest->i_atime = src->i_atime; + dest->i_mtime = src->i_mtime; + dest->i_ctime = src->i_ctime; +} + +static void ecryptfs_copy_attr_timesizes(struct inode *dest, + const struct inode *src) +{ + dest->i_atime = src->i_atime; + dest->i_mtime = src->i_mtime; + dest->i_ctime = src->i_ctime; + ecryptfs_copy_inode_size(dest, src); +} + +void ecryptfs_copy_attr_all(struct inode *dest, const struct inode *src) +{ + dest->i_mode = src->i_mode; + dest->i_nlink = src->i_nlink; + dest->i_uid = src->i_uid; + dest->i_gid = src->i_gid; + dest->i_rdev = src->i_rdev; + dest->i_atime = src->i_atime; + dest->i_mtime = src->i_mtime; + dest->i_ctime = src->i_ctime; + dest->i_blkbits = src->i_blkbits; + dest->i_flags = src->i_flags; +} + +/** + * ecryptfs_create_underlying_file + * @lower_dir_inode: inode of the parent in the lower fs of the new file + * @lower_dentry: New file's dentry in the lower fs + * @ecryptfs_dentry: New file's dentry in ecryptfs + * @mode: The mode of the new file + * @nd: nameidata of ecryptfs' parent's dentry & vfsmount + * + * Creates the file in the lower file system. + * + * Returns zero on success; non-zero on error condition + */ +static int +ecryptfs_create_underlying_file(struct inode *lower_dir_inode, + struct dentry *dentry, int mode, + struct nameidata *nd) +{ + struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); + struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry); + struct dentry *dentry_save; + struct vfsmount *vfsmount_save; + int rc; + + dentry_save = nd->dentry; + vfsmount_save = nd->mnt; + nd->dentry = lower_dentry; + nd->mnt = lower_mnt; + rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd); + nd->dentry = dentry_save; + nd->mnt = vfsmount_save; + return rc; +} + +/** + * ecryptfs_do_create + * @directory_inode: inode of the new file's dentry's parent in ecryptfs + * @ecryptfs_dentry: New file's dentry in ecryptfs + * @mode: The mode of the new file + * @nd: nameidata of ecryptfs' parent's dentry & vfsmount + * + * Creates the underlying file and the eCryptfs inode which will link to + * it. It will also update the eCryptfs directory inode to mimic the + * stat of the lower directory inode. + * + * Returns zero on success; non-zero on error condition + */ +static int +ecryptfs_do_create(struct inode *directory_inode, + struct dentry *ecryptfs_dentry, int mode, + struct nameidata *nd) +{ + int rc; + struct dentry *lower_dentry; + struct dentry *lower_dir_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); + lower_dir_dentry = lock_parent(lower_dentry); + if (unlikely(IS_ERR(lower_dir_dentry))) { + ecryptfs_printk(KERN_ERR, "Error locking directory of " + "dentry\n"); + rc = PTR_ERR(lower_dir_dentry); + goto out; + } + rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode, + ecryptfs_dentry, mode, nd); + if (unlikely(rc)) { + ecryptfs_printk(KERN_ERR, + "Failure to create underlying file\n"); + goto out_lock; + } + rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry, + directory_inode->i_sb, 0); + if (rc) { + ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n"); + goto out_lock; + } + ecryptfs_copy_attr_timesizes(directory_inode, + lower_dir_dentry->d_inode); +out_lock: + unlock_dir(lower_dir_dentry); +out: + return rc; +} + +/** + * grow_file + * @ecryptfs_dentry: the ecryptfs dentry + * @lower_file: The lower file + * @inode: The ecryptfs inode + * @lower_inode: The lower inode + * + * This is the code which will grow the file to its correct size. + */ +static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file, + struct inode *inode, struct inode *lower_inode) +{ + int rc = 0; + struct file fake_file; + struct ecryptfs_file_info tmp_file_info; + + memset(&fake_file, 0, sizeof(fake_file)); + fake_file.f_dentry = ecryptfs_dentry; + memset(&tmp_file_info, 0, sizeof(tmp_file_info)); + ecryptfs_set_file_private(&fake_file, &tmp_file_info); + ecryptfs_set_file_lower(&fake_file, lower_file); + rc = ecryptfs_fill_zeros(&fake_file, 1); + if (rc) { + ECRYPTFS_SET_FLAG( + ecryptfs_inode_to_private(inode)->crypt_stat.flags, + ECRYPTFS_SECURITY_WARNING); + ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros " + "in file; rc = [%d]\n", rc); + goto out; + } + i_size_write(inode, 0); + ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode); + ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags, + ECRYPTFS_NEW_FILE); +out: + return rc; +} + +/** + * ecryptfs_initialize_file + * + * Cause the file to be changed from a basic empty file to an ecryptfs + * file with a header and first data page. + * + * Returns zero on success + */ +static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry) +{ + int rc = 0; + int lower_flags; + struct ecryptfs_crypt_stat *crypt_stat; + struct dentry *lower_dentry; + struct dentry *tlower_dentry = NULL; + struct file *lower_file; + struct inode *inode, *lower_inode; + struct vfsmount *lower_mnt; + + lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); + ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n", + lower_dentry->d_name.name); + inode = ecryptfs_dentry->d_inode; + crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; + tlower_dentry = dget(lower_dentry); + if (!tlower_dentry) { + rc = -ENOMEM; + ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry\n"); + goto out; + } + lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR; +#if BITS_PER_LONG != 32 + lower_flags |= O_LARGEFILE; +#endif + lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry); + mntget(lower_mnt); + /* Corresponding fput() at end of this function */ + lower_file = dentry_open(tlower_dentry, lower_mnt, lower_flags); + if (IS_ERR(lower_file)) { + rc = PTR_ERR(lower_file); + ecryptfs_printk(KERN_ERR, + "Error opening dentry; rc = [%i]\n", rc); + goto out; + } + /* fput(lower_file) should handle the puts if we do this */ + lower_file->f_dentry = tlower_dentry; + lower_file->f_vfsmnt = lower_mnt; + lower_inode = tlower_dentry->d_inode; + if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { + ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); + ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED); + goto out_fput; + } + ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE); + ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n"); + rc = ecryptfs_new_file_context(ecryptfs_dentry); + if (rc) { + ecryptfs_printk(KERN_DEBUG, "Error creating new file " + "context\n"); + goto out_fput; + } + rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file); + if (rc) { + ecryptfs_printk(KERN_DEBUG, "Error writing headers\n"); + goto out_fput; + } + rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode); +out_fput: + fput(lower_file); +out: + return rc; +} + +/** + * ecryptfs_create + * @dir: The inode of the directory in which to create the file. + * @dentry: The eCryptfs dentry + * @mode: The mode of the new file. + * @nd: nameidata + * + * Creates a new file. + * + * Returns zero on success; non-zero on error condition + */ +static int +ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry, + int mode, struct nameidata *nd) +{ + int rc; + + rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd); + if (unlikely(rc)) { + ecryptfs_printk(KERN_WARNING, "Failed to create file in" + "lower filesystem\n"); + goto out; + } + /* At this point, a file exists on "disk"; we need to make sure + * that this on disk file is prepared to be an ecryptfs file */ + rc = ecryptfs_initialize_file(ecryptfs_dentry); +out: + return rc; +} + +/** + * ecryptfs_lookup + * @dir: inode + * @dentry: The dentry + * @nd: nameidata, may be NULL + * + * Find a file on disk. If the file does not exist, then we'll add it to the + * dentry cache and continue on to read it from the disk. + */ +static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry, + struct nameidata *nd) +{ + int rc = 0; + struct dentry *lower_dir_dentry; + struct dentry *lower_dentry; + struct vfsmount *lower_mnt; + struct dentry *tlower_dentry = NULL; + char *encoded_name; + unsigned int encoded_namelen; + struct ecryptfs_crypt_stat *crypt_stat = NULL; + char *page_virt = NULL; + struct inode *lower_inode; + u64 file_size; + + lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent); + dentry->d_op = &ecryptfs_dops; + if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, ".")) + || (dentry->d_name.len == 2 && !strcmp(dentry->d_name.name, ".."))) + goto out_drop; + encoded_namelen = ecryptfs_encode_filename(crypt_stat, + dentry->d_name.name, + dentry->d_name.len, + &encoded_name); + if (encoded_namelen < 0) { + rc = encoded_namelen; + goto out_drop; + } + ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen " + "= [%d]\n", encoded_name, encoded_namelen); + lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry, + encoded_namelen - 1); + kfree(encoded_name); + lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent)); + if (IS_ERR(lower_dentry)) { + ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n"); + rc = PTR_ERR(lower_dentry); + goto out_drop; + } + ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->" + "d_name.name = [%s]\n", lower_dentry, + lower_dentry->d_name.name); + lower_inode = lower_dentry->d_inode; + ecryptfs_copy_attr_atime(dir, lower_dir_dentry->d_inode); + BUG_ON(!atomic_read(&lower_dentry->d_count)); + ecryptfs_set_dentry_private(dentry, + kmem_cache_alloc(ecryptfs_dentry_info_cache, + SLAB_KERNEL)); + if (!ecryptfs_dentry_to_private(dentry)) { + rc = -ENOMEM; + ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting " + "to allocate ecryptfs_dentry_info struct\n"); + goto out_dput; + } + ecryptfs_set_dentry_lower(dentry, lower_dentry); + ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt); + if (!lower_dentry->d_inode) { + /* We want to add because we couldn't find in lower */ + d_add(dentry, NULL); + goto out; + } + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error interposing\n"); + goto out_dput; + } + if (S_ISDIR(lower_inode->i_mode)) { + ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n"); + goto out; + } + if (S_ISLNK(lower_inode->i_mode)) { + ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n"); + goto out; + } + if (!nd) { + ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave" + "as we *think* we are about to unlink\n"); + goto out; + } + tlower_dentry = dget(lower_dentry); + if (!tlower_dentry || IS_ERR(tlower_dentry)) { + rc = -ENOMEM; + ecryptfs_printk(KERN_ERR, "Cannot dget lower_dentry\n"); + goto out_dput; + } + /* Released in this function */ + page_virt = + (char *)kmem_cache_alloc(ecryptfs_header_cache_2, + SLAB_USER); + if (!page_virt) { + rc = -ENOMEM; + ecryptfs_printk(KERN_ERR, + "Cannot ecryptfs_kmalloc a page\n"); + goto out_dput; + } + memset(page_virt, 0, PAGE_CACHE_SIZE); + rc = ecryptfs_read_header_region(page_virt, tlower_dentry, nd->mnt); + crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; + if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED)) + ecryptfs_set_default_sizes(crypt_stat); + if (rc) { + rc = 0; + ecryptfs_printk(KERN_WARNING, "Error reading header region;" + " assuming unencrypted\n"); + } else { + if (!contains_ecryptfs_marker(page_virt + + ECRYPTFS_FILE_SIZE_BYTES)) { + kmem_cache_free(ecryptfs_header_cache_2, page_virt); + goto out; + } + memcpy(&file_size, page_virt, sizeof(file_size)); + file_size = be64_to_cpu(file_size); + i_size_write(dentry->d_inode, (loff_t)file_size); + } + kmem_cache_free(ecryptfs_header_cache_2, page_virt); + goto out; + +out_dput: + dput(lower_dentry); + if (tlower_dentry) + dput(tlower_dentry); +out_drop: + d_drop(dentry); +out: + return ERR_PTR(rc); +} + +static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, + struct dentry *new_dentry) +{ + struct dentry *lower_old_dentry; + struct dentry *lower_new_dentry; + struct dentry *lower_dir_dentry; + u64 file_size_save; + int rc; + + file_size_save = i_size_read(old_dentry->d_inode); + lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); + lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); + dget(lower_old_dentry); + dget(lower_new_dentry); + lower_dir_dentry = lock_parent(lower_new_dentry); + rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, + lower_new_dentry); + if (rc || !lower_new_dentry->d_inode) + goto out_lock; + rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0); + if (rc) + goto out_lock; + ecryptfs_copy_attr_timesizes(dir, lower_new_dentry->d_inode); + old_dentry->d_inode->i_nlink = + ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink; + i_size_write(new_dentry->d_inode, file_size_save); +out_lock: + unlock_dir(lower_dir_dentry); + dput(lower_new_dentry); + dput(lower_old_dentry); + if (!new_dentry->d_inode) + d_drop(new_dentry); + return rc; +} + +static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) +{ + int rc = 0; + struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); + struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); + + lock_parent(lower_dentry); + rc = vfs_unlink(lower_dir_inode, lower_dentry); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error in vfs_unlink\n"); + goto out_unlock; + } + ecryptfs_copy_attr_times(dir, lower_dir_inode); + dentry->d_inode->i_nlink = + ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink; + dentry->d_inode->i_ctime = dir->i_ctime; +out_unlock: + unlock_parent(lower_dentry); + return rc; +} + +static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, + const char *symname) +{ + int rc; + struct dentry *lower_dentry; + struct dentry *lower_dir_dentry; + umode_t mode; + char *encoded_symname; + unsigned int encoded_symlen; + struct ecryptfs_crypt_stat *crypt_stat = NULL; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + dget(lower_dentry); + lower_dir_dentry = lock_parent(lower_dentry); + mode = S_IALLUGO; + encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname, + strlen(symname), + &encoded_symname); + if (encoded_symlen < 0) { + rc = encoded_symlen; + goto out_lock; + } + rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry, + encoded_symname, mode); + kfree(encoded_symname); + if (rc || !lower_dentry->d_inode) + goto out_lock; + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); + if (rc) + goto out_lock; + ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode); +out_lock: + unlock_dir(lower_dir_dentry); + dput(lower_dentry); + if (!dentry->d_inode) + d_drop(dentry); + return rc; +} + +static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) +{ + int rc; + struct dentry *lower_dentry; + struct dentry *lower_dir_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + lower_dir_dentry = lock_parent(lower_dentry); + rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode); + if (rc || !lower_dentry->d_inode) + goto out; + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); + if (rc) + goto out; + ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode); + dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; +out: + unlock_dir(lower_dir_dentry); + if (!dentry->d_inode) + d_drop(dentry); + return rc; +} + +static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + int rc = 0; + struct dentry *tdentry = NULL; + struct dentry *lower_dentry; + struct dentry *tlower_dentry = NULL; + struct dentry *lower_dir_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + if (!(tdentry = dget(dentry))) { + rc = -EINVAL; + ecryptfs_printk(KERN_ERR, "Error dget'ing dentry [%p]\n", + dentry); + goto out; + } + lower_dir_dentry = lock_parent(lower_dentry); + if (!(tlower_dentry = dget(lower_dentry))) { + rc = -EINVAL; + ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry " + "[%p]\n", lower_dentry); + goto out; + } + rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry); + if (!rc) { + d_delete(tlower_dentry); + tlower_dentry = NULL; + } + ecryptfs_copy_attr_times(dir, lower_dir_dentry->d_inode); + dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; + unlock_dir(lower_dir_dentry); + if (!rc) + d_drop(dentry); +out: + if (tdentry) + dput(tdentry); + if (tlower_dentry) + dput(tlower_dentry); + return rc; +} + +static int +ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) +{ + int rc; + struct dentry *lower_dentry; + struct dentry *lower_dir_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + lower_dir_dentry = lock_parent(lower_dentry); + rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); + if (rc || !lower_dentry->d_inode) + goto out; + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); + if (rc) + goto out; + ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode); +out: + unlock_dir(lower_dir_dentry); + if (!dentry->d_inode) + d_drop(dentry); + return rc; +} + +static int +ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + int rc; + struct dentry *lower_old_dentry; + struct dentry *lower_new_dentry; + struct dentry *lower_old_dir_dentry; + struct dentry *lower_new_dir_dentry; + + lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); + lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); + dget(lower_old_dentry); + dget(lower_new_dentry); + lower_old_dir_dentry = dget_parent(lower_old_dentry); + lower_new_dir_dentry = dget_parent(lower_new_dentry); + lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); + rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry, + lower_new_dir_dentry->d_inode, lower_new_dentry); + if (rc) + goto out_lock; + ecryptfs_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode); + if (new_dir != old_dir) + ecryptfs_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode); +out_lock: + unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); + dput(lower_new_dentry); + dput(lower_old_dentry); + return rc; +} + +static int +ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz) +{ + int rc; + struct dentry *lower_dentry; + char *decoded_name; + char *lower_buf; + mm_segment_t old_fs; + struct ecryptfs_crypt_stat *crypt_stat; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + if (!lower_dentry->d_inode->i_op || + !lower_dentry->d_inode->i_op->readlink) { + rc = -EINVAL; + goto out; + } + /* Released in this function */ + lower_buf = kmalloc(bufsiz, GFP_KERNEL); + if (lower_buf == NULL) { + ecryptfs_printk(KERN_ERR, "Out of memory\n"); + rc = -ENOMEM; + goto out; + } + old_fs = get_fs(); + set_fs(get_ds()); + ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ " + "lower_dentry->d_name.name = [%s]\n", + lower_dentry->d_name.name); + rc = lower_dentry->d_inode->i_op->readlink(lower_dentry, + (char __user *)lower_buf, + bufsiz); + set_fs(old_fs); + if (rc >= 0) { + crypt_stat = NULL; + rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc, + &decoded_name); + if (rc == -ENOMEM) + goto out_free_lower_buf; + if (rc > 0) { + ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes " + "to userspace: [%*s]\n", rc, + decoded_name); + if (copy_to_user(buf, decoded_name, rc)) + rc = -EFAULT; + } + kfree(decoded_name); + ecryptfs_copy_attr_atime(dentry->d_inode, + lower_dentry->d_inode); + } +out_free_lower_buf: + kfree(lower_buf); +out: + return rc; +} + +static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + char *buf; + int len = PAGE_SIZE, rc; + mm_segment_t old_fs; + + /* Released in ecryptfs_put_link(); only release here on error */ + buf = kmalloc(len, GFP_KERNEL); + if (!buf) { + rc = -ENOMEM; + goto out; + } + old_fs = get_fs(); + set_fs(get_ds()); + ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ " + "dentry->d_name.name = [%s]\n", dentry->d_name.name); + rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len); + buf[rc] = '\0'; + set_fs(old_fs); + if (rc < 0) + goto out_free; + rc = 0; + nd_set_link(nd, buf); + goto out; +out_free: + kfree(buf); +out: + return ERR_PTR(rc); +} + +static void +ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr) +{ + /* Free the char* */ + kfree(nd_get_link(nd)); +} + +/** + * upper_size_to_lower_size + * @crypt_stat: Crypt_stat associated with file + * @upper_size: Size of the upper file + * + * Calculate the requried size of the lower file based on the + * specified size of the upper file. This calculation is based on the + * number of headers in the underlying file and the extent size. + * + * Returns Calculated size of the lower file. + */ +static loff_t +upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, + loff_t upper_size) +{ + loff_t lower_size; + + lower_size = ( crypt_stat->header_extent_size + * crypt_stat->num_header_extents_at_front ); + if (upper_size != 0) { + loff_t num_extents; + + num_extents = upper_size >> crypt_stat->extent_shift; + if (upper_size & ~crypt_stat->extent_mask) + num_extents++; + lower_size += (num_extents * crypt_stat->extent_size); + } + return lower_size; +} + +/** + * ecryptfs_truncate + * @dentry: The ecryptfs layer dentry + * @new_length: The length to expand the file to + * + * Function to handle truncations modifying the size of the file. Note + * that the file sizes are interpolated. When expanding, we are simply + * writing strings of 0's out. When truncating, we need to modify the + * underlying file size according to the page index interpolations. + * + * Returns zero on success; non-zero otherwise + */ +int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) +{ + int rc = 0; + struct inode *inode = dentry->d_inode; + struct dentry *lower_dentry; + struct vfsmount *lower_mnt; + struct file fake_ecryptfs_file, *lower_file = NULL; + struct ecryptfs_crypt_stat *crypt_stat; + loff_t i_size = i_size_read(inode); + loff_t lower_size_before_truncate; + loff_t lower_size_after_truncate; + + if (unlikely((new_length == i_size))) + goto out; + crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; + /* Set up a fake ecryptfs file, this is used to interface with + * the file in the underlying filesystem so that the + * truncation has an effect there as well. */ + memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file)); + fake_ecryptfs_file.f_dentry = dentry; + /* Released at out_free: label */ + ecryptfs_set_file_private(&fake_ecryptfs_file, + kmem_cache_alloc(ecryptfs_file_info_cache, + SLAB_KERNEL)); + if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) { + rc = -ENOMEM; + goto out; + } + lower_dentry = ecryptfs_dentry_to_lower(dentry); + /* This dget & mntget is released through fput at out_fput: */ + dget(lower_dentry); + lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry); + mntget(lower_mnt); + lower_file = dentry_open(lower_dentry, lower_mnt, O_RDWR); + if (unlikely(IS_ERR(lower_file))) { + rc = PTR_ERR(lower_file); + goto out_free; + } + ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file); + /* Switch on growing or shrinking file */ + if (new_length > i_size) { + rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length); + if (rc) { + ecryptfs_printk(KERN_ERR, + "Problem with fill_zeros\n"); + goto out_fput; + } + i_size_write(inode, new_length); + rc = ecryptfs_write_inode_size_to_header(lower_file, + lower_dentry->d_inode, + inode); + if (rc) { + ecryptfs_printk(KERN_ERR, + "Problem with ecryptfs_write" + "_inode_size\n"); + goto out_fput; + } + } else { /* new_length < i_size_read(inode) */ + vmtruncate(inode, new_length); + ecryptfs_write_inode_size_to_header(lower_file, + lower_dentry->d_inode, + inode); + /* We are reducing the size of the ecryptfs file, and need to + * know if we need to reduce the size of the lower file. */ + lower_size_before_truncate = + upper_size_to_lower_size(crypt_stat, i_size); + lower_size_after_truncate = + upper_size_to_lower_size(crypt_stat, new_length); + if (lower_size_after_truncate < lower_size_before_truncate) + vmtruncate(lower_dentry->d_inode, + lower_size_after_truncate); + } + /* Update the access times */ + lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime + = CURRENT_TIME; + mark_inode_dirty_sync(inode); +out_fput: + fput(lower_file); +out_free: + if (ecryptfs_file_to_private(&fake_ecryptfs_file)) + kmem_cache_free(ecryptfs_file_info_cache, + ecryptfs_file_to_private(&fake_ecryptfs_file)); +out: + return rc; +} + +static int +ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd) +{ + int rc; + + if (nd) { + struct vfsmount *vfsmnt_save = nd->mnt; + struct dentry *dentry_save = nd->dentry; + + nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry); + nd->dentry = ecryptfs_dentry_to_lower(nd->dentry); + rc = permission(ecryptfs_inode_to_lower(inode), mask, nd); + nd->mnt = vfsmnt_save; + nd->dentry = dentry_save; + } else + rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL); + return rc; +} + +/** + * ecryptfs_setattr + * @dentry: dentry handle to the inode to modify + * @ia: Structure with flags of what to change and values + * + * Updates the metadata of an inode. If the update is to the size + * i.e. truncation, then ecryptfs_truncate will handle the size modification + * of both the ecryptfs inode and the lower inode. + * + * All other metadata changes will be passed right to the lower filesystem, + * and we will just update our inode to look like the lower. + */ +static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) +{ + int rc = 0; + struct dentry *lower_dentry; + struct inode *inode; + struct inode *lower_inode; + struct ecryptfs_crypt_stat *crypt_stat; + + crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; + lower_dentry = ecryptfs_dentry_to_lower(dentry); + inode = dentry->d_inode; + lower_inode = ecryptfs_inode_to_lower(inode); + if (ia->ia_valid & ATTR_SIZE) { + ecryptfs_printk(KERN_DEBUG, + "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n", + ia->ia_valid, ATTR_SIZE); + rc = ecryptfs_truncate(dentry, ia->ia_size); + /* ecryptfs_truncate handles resizing of the lower file */ + ia->ia_valid &= ~ATTR_SIZE; + ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n", + ia->ia_valid); + if (rc < 0) + goto out; + } + rc = notify_change(lower_dentry, ia); +out: + ecryptfs_copy_attr_all(inode, lower_inode); + return rc; +} + +static int +ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, + size_t size, int flags) +{ + int rc = 0; + struct dentry *lower_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + if (!lower_dentry->d_inode->i_op->setxattr) { + rc = -ENOSYS; + goto out; + } + mutex_lock(&lower_dentry->d_inode->i_mutex); + rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value, + size, flags); + mutex_unlock(&lower_dentry->d_inode->i_mutex); +out: + return rc; +} + +static ssize_t +ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value, + size_t size) +{ + int rc = 0; + struct dentry *lower_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + if (!lower_dentry->d_inode->i_op->getxattr) { + rc = -ENOSYS; + goto out; + } + mutex_lock(&lower_dentry->d_inode->i_mutex); + rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value, + size); + mutex_unlock(&lower_dentry->d_inode->i_mutex); +out: + return rc; +} + +static ssize_t +ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) +{ + int rc = 0; + struct dentry *lower_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + if (!lower_dentry->d_inode->i_op->listxattr) { + rc = -ENOSYS; + goto out; + } + mutex_lock(&lower_dentry->d_inode->i_mutex); + rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size); + mutex_unlock(&lower_dentry->d_inode->i_mutex); +out: + return rc; +} + +static int ecryptfs_removexattr(struct dentry *dentry, const char *name) +{ + int rc = 0; + struct dentry *lower_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + if (!lower_dentry->d_inode->i_op->removexattr) { + rc = -ENOSYS; + goto out; + } + mutex_lock(&lower_dentry->d_inode->i_mutex); + rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name); + mutex_unlock(&lower_dentry->d_inode->i_mutex); +out: + return rc; +} + +int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode) +{ + if ((ecryptfs_inode_to_lower(inode) + == (struct inode *)candidate_lower_inode)) + return 1; + else + return 0; +} + +int ecryptfs_inode_set(struct inode *inode, void *lower_inode) +{ + ecryptfs_init_inode(inode, (struct inode *)lower_inode); + return 0; +} + +struct inode_operations ecryptfs_symlink_iops = { + .readlink = ecryptfs_readlink, + .follow_link = ecryptfs_follow_link, + .put_link = ecryptfs_put_link, + .permission = ecryptfs_permission, + .setattr = ecryptfs_setattr, + .setxattr = ecryptfs_setxattr, + .getxattr = ecryptfs_getxattr, + .listxattr = ecryptfs_listxattr, + .removexattr = ecryptfs_removexattr +}; + +struct inode_operations ecryptfs_dir_iops = { + .create = ecryptfs_create, + .lookup = ecryptfs_lookup, + .link = ecryptfs_link, + .unlink = ecryptfs_unlink, + .symlink = ecryptfs_symlink, + .mkdir = ecryptfs_mkdir, + .rmdir = ecryptfs_rmdir, + .mknod = ecryptfs_mknod, + .rename = ecryptfs_rename, + .permission = ecryptfs_permission, + .setattr = ecryptfs_setattr, + .setxattr = ecryptfs_setxattr, + .getxattr = ecryptfs_getxattr, + .listxattr = ecryptfs_listxattr, + .removexattr = ecryptfs_removexattr +}; + +struct inode_operations ecryptfs_main_iops = { + .permission = ecryptfs_permission, + .setattr = ecryptfs_setattr, + .setxattr = ecryptfs_setxattr, + .getxattr = ecryptfs_getxattr, + .listxattr = ecryptfs_listxattr, + .removexattr = ecryptfs_removexattr +}; |