--- /dev/null
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2004 Erez Zadok
+ * Copyright (C) 2001-2004 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ * Author(s): Michael A. Halcrow <mhalcrow@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/file.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/security.h>
+#include <linux/compat.h>
+#include <linux/fs_stack.h>
+#include "ecryptfs_kernel.h"
+
+/**
+ * ecryptfs_read_update_atime
+ *
+ * generic_file_read updates the atime of upper layer inode. But, it
+ * doesn't give us a chance to update the atime of the lower layer
+ * inode. This function is a wrapper to generic_file_read. It
+ * updates the atime of the lower level inode if generic_file_read
+ * returns without any errors. This is to be used only for file reads.
+ * The function to be used for directory reads is ecryptfs_read.
+ */
+static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
+ struct iov_iter *to)
+{
+ ssize_t rc;
+ struct path *path;
+ struct file *file = iocb->ki_filp;
+
+ rc = generic_file_read_iter(iocb, to);
+ if (rc >= 0) {
+ path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
+ touch_atime(path);
+ }
+ return rc;
+}
+
+struct ecryptfs_getdents_callback {
+ struct dir_context ctx;
+ struct dir_context *caller;
+ struct super_block *sb;
+ int filldir_called;
+ int entries_written;
+};
+
+/* Inspired by generic filldir in fs/readdir.c */
+static int
+ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,
+ int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)
+{
+ struct ecryptfs_getdents_callback *buf =
+ container_of(ctx, struct ecryptfs_getdents_callback, ctx);
+ size_t name_size;
+ char *name;
+ int rc;
+
+ buf->filldir_called++;
+ rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
+ buf->sb, lower_name,
+ lower_namelen);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to decode and decrypt "
+ "filename [%s]; rc = [%d]\n", __func__, lower_name,
+ rc);
+ goto out;
+ }
+ buf->caller->pos = buf->ctx.pos;
+ rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
+ kfree(name);
+ if (!rc)
+ buf->entries_written++;
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_readdir
+ * @file: The eCryptfs directory file
+ * @ctx: The actor to feed the entries to
+ */
+static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
+{
+ int rc;
+ struct file *lower_file;
+ struct inode *inode = file_inode(file);
+ struct ecryptfs_getdents_callback buf = {
+ .ctx.actor = ecryptfs_filldir,
+ .caller = ctx,
+ .sb = inode->i_sb,
+ };
+ lower_file = ecryptfs_file_to_lower(file);
+ lower_file->f_pos = ctx->pos;
+ rc = iterate_dir(lower_file, &buf.ctx);
+ ctx->pos = buf.ctx.pos;
+ if (rc < 0)
+ goto out;
+ if (buf.filldir_called && !buf.entries_written)
+ goto out;
+ if (rc >= 0)
+ fsstack_copy_attr_atime(inode,
+ file_inode(lower_file));
+out:
+ return rc;
+}
+
+struct kmem_cache *ecryptfs_file_info_cache;
+
+static int read_or_initialize_metadata(struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+ struct ecryptfs_crypt_stat *crypt_stat;
+ int rc;
+
+ crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+ mount_crypt_stat = &ecryptfs_superblock_to_private(
+ inode->i_sb)->mount_crypt_stat;
+ mutex_lock(&crypt_stat->cs_mutex);
+
+ if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
+ crypt_stat->flags & ECRYPTFS_KEY_VALID) {
+ rc = 0;
+ goto out;
+ }
+
+ rc = ecryptfs_read_metadata(dentry);
+ if (!rc)
+ goto out;
+
+ if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
+ crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
+ | ECRYPTFS_ENCRYPTED);
+ rc = 0;
+ goto out;
+ }
+
+ if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
+ !i_size_read(ecryptfs_inode_to_lower(inode))) {
+ rc = ecryptfs_initialize_file(dentry, inode);
+ if (!rc)
+ goto out;
+ }
+
+ rc = -EIO;
+out:
+ mutex_unlock(&crypt_stat->cs_mutex);
+ return rc;
+}
+
+/**
+ * ecryptfs_open
+ * @inode: inode speciying file to open
+ * @file: Structure to return filled in
+ *
+ * Opens the file specified by inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_open(struct inode *inode, struct file *file)
+{
+ int rc = 0;
+ struct ecryptfs_crypt_stat *crypt_stat = NULL;
+ struct dentry *ecryptfs_dentry = file->f_path.dentry;
+ /* Private value of ecryptfs_dentry allocated in
+ * ecryptfs_lookup() */
+ struct ecryptfs_file_info *file_info;
+
+ /* Released in ecryptfs_release or end of function if failure */
+ file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
+ ecryptfs_set_file_private(file, file_info);
+ if (!file_info) {
+ ecryptfs_printk(KERN_ERR,
+ "Error attempting to allocate memory\n");
+ rc = -ENOMEM;
+ goto out;
+ }
+ crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+ mutex_lock(&crypt_stat->cs_mutex);
+ if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
+ ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
+ /* Policy code enabled in future release */
+ crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
+ | ECRYPTFS_ENCRYPTED);
+ }
+ mutex_unlock(&crypt_stat->cs_mutex);
+ rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to initialize "
+ "the lower file for the dentry with name "
+ "[%pd]; rc = [%d]\n", __func__,
+ ecryptfs_dentry, rc);
+ goto out_free;
+ }
+ if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
+ == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
+ rc = -EPERM;
+ printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
+ "file must hence be opened RO\n", __func__);
+ goto out_put;
+ }
+ ecryptfs_set_file_lower(
+ file, ecryptfs_inode_to_private(inode)->lower_file);
+ if (d_is_dir(ecryptfs_dentry)) {
+ ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
+ mutex_lock(&crypt_stat->cs_mutex);
+ crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
+ mutex_unlock(&crypt_stat->cs_mutex);
+ rc = 0;
+ goto out;
+ }
+ rc = read_or_initialize_metadata(ecryptfs_dentry);
+ if (rc)
+ goto out_put;
+ ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
+ "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
+ (unsigned long long)i_size_read(inode));
+ goto out;
+out_put:
+ ecryptfs_put_lower_file(inode);
+out_free:
+ kmem_cache_free(ecryptfs_file_info_cache,
+ ecryptfs_file_to_private(file));
+out:
+ return rc;
+}
+
+static int ecryptfs_flush(struct file *file, fl_owner_t td)
+{
+ struct file *lower_file = ecryptfs_file_to_lower(file);
+
+ if (lower_file->f_op->flush) {
+ filemap_write_and_wait(file->f_mapping);
+ return lower_file->f_op->flush(lower_file, td);
+ }
+
+ return 0;
+}
+
+static int ecryptfs_release(struct inode *inode, struct file *file)
+{
+ ecryptfs_put_lower_file(inode);
+ kmem_cache_free(ecryptfs_file_info_cache,
+ ecryptfs_file_to_private(file));
+ return 0;
+}
+
+static int
+ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+ int rc;
+
+ rc = filemap_write_and_wait(file->f_mapping);
+ if (rc)
+ return rc;
+
+ return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
+}
+
+static int ecryptfs_fasync(int fd, struct file *file, int flag)
+{
+ int rc = 0;
+ struct file *lower_file = NULL;
+
+ lower_file = ecryptfs_file_to_lower(file);
+ if (lower_file->f_op->fasync)
+ rc = lower_file->f_op->fasync(fd, lower_file, flag);
+ return rc;
+}
+
+static long
+ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct file *lower_file = ecryptfs_file_to_lower(file);
+ long rc = -ENOTTY;
+
+ if (!lower_file->f_op->unlocked_ioctl)
+ return rc;
+
+ switch (cmd) {
+ case FITRIM:
+ case FS_IOC_GETFLAGS:
+ case FS_IOC_SETFLAGS:
+ case FS_IOC_GETVERSION:
+ case FS_IOC_SETVERSION:
+ rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
+ fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
+
+ return rc;
+ default:
+ return rc;
+ }
+}
+
+#ifdef CONFIG_COMPAT
+static long
+ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct file *lower_file = ecryptfs_file_to_lower(file);
+ long rc = -ENOIOCTLCMD;
+
+ if (!lower_file->f_op->compat_ioctl)
+ return rc;
+
+ switch (cmd) {
+ case FITRIM:
+ case FS_IOC32_GETFLAGS:
+ case FS_IOC32_SETFLAGS:
+ case FS_IOC32_GETVERSION:
+ case FS_IOC32_SETVERSION:
+ rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
+ fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
+
+ return rc;
+ default:
+ return rc;
+ }
+}
+#endif
+
+const struct file_operations ecryptfs_dir_fops = {
+ .iterate = ecryptfs_readdir,
+ .read = generic_read_dir,
+ .unlocked_ioctl = ecryptfs_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ecryptfs_compat_ioctl,
+#endif
+ .open = ecryptfs_open,
+ .flush = ecryptfs_flush,
+ .release = ecryptfs_release,
+ .fsync = ecryptfs_fsync,
+ .fasync = ecryptfs_fasync,
+ .splice_read = generic_file_splice_read,
+ .llseek = default_llseek,
+};
+
+const struct file_operations ecryptfs_main_fops = {
+ .llseek = generic_file_llseek,
+ .read_iter = ecryptfs_read_update_atime,
+ .write_iter = generic_file_write_iter,
+ .iterate = ecryptfs_readdir,
+ .unlocked_ioctl = ecryptfs_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ecryptfs_compat_ioctl,
+#endif
+ .mmap = generic_file_mmap,
+ .open = ecryptfs_open,
+ .flush = ecryptfs_flush,
+ .release = ecryptfs_release,
+ .fsync = ecryptfs_fsync,
+ .fasync = ecryptfs_fasync,
+ .splice_read = generic_file_splice_read,
+};
Code Review / kvmfornfv.git / blobdiff