| /** | 
 |  * 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 "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 err; | 
 | 	int filldir_called; | 
 | 	int entries_written; | 
 | }; | 
 |  | 
 | /* Inspired by generic filldir in fs/readir.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; | 
 | retry: | 
 | 	buf.filldir_called = 0; | 
 | 	buf.entries_written = 0; | 
 | 	buf.err = 0; | 
 | 	rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf); | 
 | 	if (buf.err) | 
 | 		rc = buf.err; | 
 | 	if (buf.filldir_called && !buf.entries_written) | 
 | 		goto retry; | 
 | 	file->f_pos = lower_file->f_pos; | 
 | 	if (rc >= 0) | 
 | 		fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode); | 
 | 	return rc; | 
 | } | 
 |  | 
 | struct kmem_cache *ecryptfs_file_info_cache; | 
 |  | 
 | int ecryptfs_open_lower_file(struct file **lower_file, | 
 | 			     struct dentry *lower_dentry, | 
 | 			     struct vfsmount *lower_mnt, int flags) | 
 | { | 
 | 	int rc = 0; | 
 |  | 
 | 	flags |= O_LARGEFILE; | 
 | 	dget(lower_dentry); | 
 | 	mntget(lower_mnt); | 
 | 	*lower_file = dentry_open(lower_dentry, lower_mnt, flags); | 
 | 	if (IS_ERR(*lower_file)) { | 
 | 		printk(KERN_ERR "Error opening lower file for lower_dentry " | 
 | 		       "[0x%p], lower_mnt [0x%p], and flags [0x%x]\n", | 
 | 		       lower_dentry, lower_mnt, flags); | 
 | 		rc = PTR_ERR(*lower_file); | 
 | 		*lower_file = NULL; | 
 | 		goto out; | 
 | 	} | 
 | out: | 
 | 	return rc; | 
 | } | 
 |  | 
 | int ecryptfs_close_lower_file(struct file *lower_file) | 
 | { | 
 | 	fput(lower_file); | 
 | 	return 0; | 
 | } | 
 |  | 
 | /** | 
 |  * 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 inode *lower_inode = NULL; | 
 | 	struct file *lower_file = NULL; | 
 | 	struct vfsmount *lower_mnt; | 
 | 	struct ecryptfs_file_info *file_info; | 
 | 	int lower_flags; | 
 |  | 
 | 	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; | 
 | 		crypt_stat->flags |= ECRYPTFS_ENCRYPTED; | 
 | 	} | 
 | 	mutex_unlock(&crypt_stat->cs_mutex); | 
 | 	lower_flags = file->f_flags; | 
 | 	if ((lower_flags & O_ACCMODE) == O_WRONLY) | 
 | 		lower_flags = (lower_flags & O_ACCMODE) | O_RDWR; | 
 | 	if (file->f_flags & O_APPEND) | 
 | 		lower_flags &= ~O_APPEND; | 
 | 	lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry); | 
 | 	/* Corresponding fput() in ecryptfs_release() */ | 
 | 	if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt, | 
 | 					   lower_flags))) { | 
 | 		ecryptfs_printk(KERN_ERR, "Error opening lower file\n"); | 
 | 		goto out_puts; | 
 | 	} | 
 | 	ecryptfs_set_file_lower(file, lower_file); | 
 | 	/* Isn't this check the same as the one in lookup? */ | 
 | 	lower_inode = lower_dentry->d_inode; | 
 | 	if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { | 
 | 		ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); | 
 | 		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); | 
 | 		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, lower_file); | 
 | 		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 "Attempt to read file that " | 
 | 				       "is not in a valid eCryptfs format, " | 
 | 				       "and plaintext passthrough mode is not " | 
 | 				       "enabled; returning -EIO\n"); | 
 | 				mutex_unlock(&crypt_stat->cs_mutex); | 
 | 				goto out_puts; | 
 | 			} | 
 | 			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)); | 
 | 	ecryptfs_set_file_lower(file, lower_file); | 
 | 	goto out; | 
 | out_puts: | 
 | 	mntput(lower_mnt); | 
 | 	dput(lower_dentry); | 
 | 	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) | 
 | { | 
 | 	struct file *lower_file = ecryptfs_file_to_lower(file); | 
 | 	struct ecryptfs_file_info *file_info = ecryptfs_file_to_private(file); | 
 | 	struct inode *lower_inode = ecryptfs_inode_to_lower(inode); | 
 | 	int rc; | 
 |  | 
 | 	if ((rc = ecryptfs_close_lower_file(lower_file))) { | 
 | 		printk(KERN_ERR "Error closing lower_file\n"); | 
 | 		goto out; | 
 | 	} | 
 | 	inode->i_blocks = lower_inode->i_blocks; | 
 | 	kmem_cache_free(ecryptfs_file_info_cache, file_info); | 
 | out: | 
 | 	return rc; | 
 | } | 
 |  | 
 | 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; | 
 |  | 
 | 	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); | 
 | 	return rc; | 
 | } | 
 |  | 
 | static ssize_t ecryptfs_splice_read(struct file *file, loff_t * ppos, | 
 | 				    struct pipe_inode_info *pipe, size_t count, | 
 | 				    unsigned int flags) | 
 | { | 
 | 	struct file *lower_file = NULL; | 
 | 	int rc = -EINVAL; | 
 |  | 
 | 	lower_file = ecryptfs_file_to_lower(file); | 
 | 	if (lower_file->f_op && lower_file->f_op->splice_read) | 
 | 		rc = lower_file->f_op->splice_read(lower_file, ppos, pipe, | 
 | 						count, flags); | 
 |  | 
 | 	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 = ecryptfs_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 = ecryptfs_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; | 
 | } |