| /** |
| * 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 <linux/smp_lock.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, |
| const struct iovec *iov, |
| unsigned long nr_segs, loff_t pos) |
| { |
| int rc; |
| struct dentry *lower_dentry; |
| struct vfsmount *lower_vfsmount; |
| struct file *file = iocb->ki_filp; |
| |
| rc = generic_file_aio_read(iocb, iov, nr_segs, pos); |
| /* |
| * Even though this is a async interface, we need to wait |
| * for IO to finish to update atime |
| */ |
| if (-EIOCBQUEUED == rc) |
| rc = wait_on_sync_kiocb(iocb); |
| if (rc >= 0) { |
| lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry); |
| lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry); |
| touch_atime(lower_vfsmount, lower_dentry); |
| } |
| return rc; |
| } |
| |
| struct ecryptfs_getdents_callback { |
| void *dirent; |
| struct dentry *dentry; |
| filldir_t filldir; |
| int filldir_called; |
| int entries_written; |
| }; |
| |
| /* Inspired by generic filldir in fs/readdir.c */ |
| static int |
| ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen, |
| loff_t offset, u64 ino, unsigned int d_type) |
| { |
| struct ecryptfs_getdents_callback *buf = |
| (struct ecryptfs_getdents_callback *)dirent; |
| size_t name_size; |
| char *name; |
| int rc; |
| |
| buf->filldir_called++; |
| rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size, |
| buf->dentry, 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; |
| } |
| rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type); |
| kfree(name); |
| if (rc >= 0) |
| buf->entries_written++; |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_readdir |
| * @file: The eCryptfs directory file |
| * @dirent: Directory entry handle |
| * @filldir: The filldir callback function |
| */ |
| static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir) |
| { |
| int rc; |
| struct file *lower_file; |
| struct inode *inode; |
| struct ecryptfs_getdents_callback buf; |
| |
| lower_file = ecryptfs_file_to_lower(file); |
| lower_file->f_pos = file->f_pos; |
| inode = file->f_path.dentry->d_inode; |
| memset(&buf, 0, sizeof(buf)); |
| buf.dirent = dirent; |
| buf.dentry = file->f_path.dentry; |
| buf.filldir = filldir; |
| buf.filldir_called = 0; |
| buf.entries_written = 0; |
| rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf); |
| file->f_pos = lower_file->f_pos; |
| if (rc < 0) |
| goto out; |
| if (buf.filldir_called && !buf.entries_written) |
| goto out; |
| if (rc >= 0) |
| fsstack_copy_attr_atime(inode, |
| lower_file->f_path.dentry->d_inode); |
| out: |
| return rc; |
| } |
| |
| struct kmem_cache *ecryptfs_file_info_cache; |
| |
| /** |
| * 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 ecryptfs_mount_crypt_stat *mount_crypt_stat; |
| struct dentry *ecryptfs_dentry = file->f_path.dentry; |
| /* Private value of ecryptfs_dentry allocated in |
| * ecryptfs_lookup() */ |
| struct dentry *lower_dentry; |
| struct ecryptfs_file_info *file_info; |
| |
| mount_crypt_stat = &ecryptfs_superblock_to_private( |
| ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) |
| && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR) |
| || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC) |
| || (file->f_flags & O_APPEND))) { |
| printk(KERN_WARNING "Mount has encrypted view enabled; " |
| "files may only be read\n"); |
| rc = -EPERM; |
| goto out; |
| } |
| /* 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; |
| } |
| lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
| 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); |
| if (!ecryptfs_inode_to_private(inode)->lower_file) { |
| rc = ecryptfs_init_persistent_file(ecryptfs_dentry); |
| if (rc) { |
| printk(KERN_ERR "%s: Error attempting to initialize " |
| "the persistent file for the dentry with name " |
| "[%s]; rc = [%d]\n", __func__, |
| ecryptfs_dentry->d_name.name, rc); |
| goto out_free; |
| } |
| } |
| if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY) |
| && !(file->f_flags & O_RDONLY)) { |
| rc = -EPERM; |
| printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs " |
| "file must hence be opened RO\n", __func__); |
| goto out_free; |
| } |
| ecryptfs_set_file_lower( |
| file, ecryptfs_inode_to_private(inode)->lower_file); |
| if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { |
| 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; |
| } |
| mutex_lock(&crypt_stat->cs_mutex); |
| if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) |
| || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
| rc = ecryptfs_read_metadata(ecryptfs_dentry); |
| if (rc) { |
| ecryptfs_printk(KERN_DEBUG, |
| "Valid headers not found\n"); |
| if (!(mount_crypt_stat->flags |
| & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { |
| rc = -EIO; |
| printk(KERN_WARNING "Either the lower file " |
| "is not in a valid eCryptfs format, " |
| "or the key could not be retrieved. " |
| "Plaintext passthrough mode is not " |
| "enabled; returning -EIO\n"); |
| mutex_unlock(&crypt_stat->cs_mutex); |
| goto out_free; |
| } |
| rc = 0; |
| crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
| mutex_unlock(&crypt_stat->cs_mutex); |
| goto out; |
| } |
| } |
| mutex_unlock(&crypt_stat->cs_mutex); |
| ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] " |
| "size: [0x%.16x]\n", inode, inode->i_ino, |
| i_size_read(inode)); |
| goto out; |
| 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) |
| { |
| int rc = 0; |
| struct file *lower_file = NULL; |
| |
| lower_file = ecryptfs_file_to_lower(file); |
| if (lower_file->f_op && lower_file->f_op->flush) |
| rc = lower_file->f_op->flush(lower_file, td); |
| return rc; |
| } |
| |
| static int ecryptfs_release(struct inode *inode, struct file *file) |
| { |
| kmem_cache_free(ecryptfs_file_info_cache, |
| ecryptfs_file_to_private(file)); |
| return 0; |
| } |
| |
| static int |
| ecryptfs_fsync(struct file *file, int datasync) |
| { |
| 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; |
| |
| lock_kernel(); |
| lower_file = ecryptfs_file_to_lower(file); |
| if (lower_file->f_op && lower_file->f_op->fasync) |
| rc = lower_file->f_op->fasync(fd, lower_file, flag); |
| unlock_kernel(); |
| return rc; |
| } |
| |
| static long |
| ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct file *lower_file = NULL; |
| long rc = -ENOTTY; |
| |
| if (ecryptfs_file_to_private(file)) |
| lower_file = ecryptfs_file_to_lower(file); |
| if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl) |
| rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg); |
| return rc; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long |
| ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct file *lower_file = NULL; |
| long rc = -ENOIOCTLCMD; |
| |
| if (ecryptfs_file_to_private(file)) |
| lower_file = ecryptfs_file_to_lower(file); |
| if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl) |
| rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg); |
| return rc; |
| } |
| #endif |
| |
| const struct file_operations ecryptfs_dir_fops = { |
| .readdir = ecryptfs_readdir, |
| .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 = do_sync_read, |
| .aio_read = ecryptfs_read_update_atime, |
| .write = do_sync_write, |
| .aio_write = generic_file_aio_write, |
| .readdir = 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, |
| }; |