/** * 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/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 *name, int namelen, loff_t offset, u64 ino, unsigned int d_type) { struct ecryptfs_crypt_stat *crypt_stat; struct ecryptfs_getdents_callback *buf = (struct ecryptfs_getdents_callback *)dirent; int rc; int decoded_length; char *decoded_name; crypt_stat = ecryptfs_dentry_to_private(buf->dentry)->crypt_stat; buf->filldir_called++; decoded_length = ecryptfs_decode_filename(crypt_stat, name, namelen, &decoded_name); if (decoded_length < 0) { rc = decoded_length; goto out; } rc = buf->filldir(buf->dirent, decoded_name, decoded_length, offset, ino, d_type); kfree(decoded_name); if (rc >= 0) buf->entries_written++; out: return rc; } /** * ecryptfs_readdir * @file: The ecryptfs file struct * @dirent: Directory entry * @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 = ecryptfs_dentry_to_lower(ecryptfs_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->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; } 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; } } 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, struct dentry *dentry, int datasync) { struct file *lower_file = ecryptfs_file_to_lower(file); struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); struct inode *lower_inode = lower_dentry->d_inode; int rc = -EINVAL; if (lower_inode->i_fop->fsync) { mutex_lock(&lower_inode->i_mutex); rc = lower_inode->i_fop->fsync(lower_file, lower_dentry, datasync); mutex_unlock(&lower_inode->i_mutex); } return rc; } 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 int ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg); const struct file_operations ecryptfs_dir_fops = { .readdir = ecryptfs_readdir, .ioctl = ecryptfs_ioctl, .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, }; 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, .ioctl = ecryptfs_ioctl, .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, }; static int ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int rc = 0; struct file *lower_file = NULL; if (ecryptfs_file_to_private(file)) lower_file = ecryptfs_file_to_lower(file); if (lower_file && lower_file->f_op && lower_file->f_op->ioctl) rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode), lower_file, cmd, arg); else rc = -ENOTTY; return rc; }