[PATCH 9/13: eCryptfs] Inode operations

Phillip Hellewell
2006-05-13T03:46:35Z

This is the 9th patch in a series of 13 constituting the kernel
components of the eCryptfs cryptographic filesystem.

eCryptfs inode operations. Includes functions to support inode
interpolation between upper and lower inodes.

Signed-off-by: Phillip Hellewell <phillip@hellewell.homeip.net>
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>

---

inode.c | 1080 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 1080 insertions(+)

Index: linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/inode.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/inode.c 2006-05-12 20:00:28.000000000 -0600
@@ -0,0 +1,1080 @@
+/**
+ * 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 inline 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 inline void unlock_parent(struct dentry *dentry)
+{
+ mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
+ dput(dentry->d_parent);
+}
+
+static inline 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)
+{
+ ASSERT(dest != NULL);
+ ASSERT(src != NULL);
+ dest->i_atime = src->i_atime;
+}
+
+void ecryptfs_copy_attr_times(struct inode *dest, const struct inode *src)
+{
+ ASSERT(dest != NULL);
+ ASSERT(src != NULL);
+ 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)
+{
+ ASSERT(dest != NULL);
+ ASSERT(src != NULL);
+ 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)
+{
+ ASSERT(dest != NULL);
+ ASSERT(src != NULL);
+ 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_blksize = src->i_blksize;
+ 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 & vfsmnt
+ *
+ * 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 *lower_dentry,
+ struct dentry *ecryptfs_dentry, int mode,
+ struct nameidata *nd)
+{
+ int rc;
+ struct dentry *saved_dentry = NULL;
+ struct vfsmount *saved_vfsmount = NULL;
+
+ saved_dentry = nd->dentry;
+ saved_vfsmount = nd->mnt;
+ nd->dentry = lower_dentry;
+ nd->mnt = ecryptfs_superblock_to_private(
+ ecryptfs_dentry->d_sb)->lower_mnt;
+ rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
+ nd->dentry = saved_dentry;
+ nd->mnt = saved_vfsmount;
+ 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 & vfsmnt
+ *
+ * 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);
+ if (IS_ERR(lower_dentry)) {
+ ecryptfs_printk(KERN_ERR, "ecryptfs dentry doesn't know"
+ "about its lower counterpart\n");
+ rc = PTR_ERR(lower_dentry);
+ goto out;
+ }
+ 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,
+ lower_dentry, 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);
+ if (IS_ERR(lower_dentry)) {
+ ecryptfs_printk(KERN_ERR, "ecryptfs dentry doesn't know"
+ "about its lower counterpart\n");
+ rc = PTR_ERR(lower_dentry);
+ goto out;
+ }
+ 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_superblock_to_private(inode->i_sb)->lower_mnt;
+ 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 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);
+ 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);
+ ASSERT(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);
+ 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);
+ 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)) {
+ ecryptfs_printk(KERN_WARNING, "Underlying file "
+ "lacks recognizable eCryptfs marker\n");
+ }
+ 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)
+{
+ int rc;
+ struct dentry *lower_old_dentry;
+ struct dentry *lower_new_dentry;
+ struct dentry *lower_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_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;
+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 inline 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 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;
+ if (unlikely(!crypt_stat)) {
+ ecryptfs_printk(KERN_ERR, "NULL crypt_stat on dentry with "
+ "d_name.name = [%s]\n", dentry->d_name.name);
+ rc = -EINVAL;
+ goto out;
+ }
+ /* 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);
+ mntget(ecryptfs_superblock_to_private(inode->i_sb)->lower_mnt);
+ lower_file = dentry_open(
+ lower_dentry,
+ ecryptfs_superblock_to_private(inode->i_sb)->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)
+{
+ struct inode *lower_inode;
+ int rc = 0;
+
+ lower_inode = ecryptfs_inode_to_lower(inode);
+ if (nd)
+ ecryptfs_printk(KERN_DEBUG, "nd->dentry = [%p]\n",
+ nd->dentry);
+ rc = permission(lower_inode, mask, nd);
+ 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;
+}
+
+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
+};