/** * 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,				const struct iovec *iov,				unsigned long nr_segs, loff_t pos){	ssize_t rc;	struct path lower;	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.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);		touch_atime(&lower);	}	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 intecryptfs_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;} static void ecryptfs_vma_close(struct vm_area_struct *vma){	filemap_write_and_wait(vma->vm_file->f_mapping);} static const struct vm_operations_struct ecryptfs_file_vm_ops = {	.close		= ecryptfs_vma_close,	.fault		= filemap_fault,}; static int ecryptfs_file_mmap(struct file *file, struct vm_area_struct *vma){	int rc; 	rc = generic_file_mmap(file, vma);	if (!rc)		vma->vm_ops = &ecryptfs_file_vm_ops; 	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);	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 "			"[%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_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 (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_put;			}			rc = 0;			crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED					       | 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%.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){	return file->f_mode & FMODE_WRITE	       ? filemap_write_and_wait(file->f_mapping) : 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 intecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync){	int rc = 0; 	rc = generic_file_fsync(file, start, end, datasync);	if (rc)		goto out;	rc = vfs_fsync_range(ecryptfs_file_to_lower(file), start, end,			     datasync);out:	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 longecryptfs_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_COMPATstatic longecryptfs_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,	.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 = 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 = ecryptfs_file_mmap,	.open = ecryptfs_open,	.flush = ecryptfs_flush,	.release = ecryptfs_release,	.fsync = ecryptfs_fsync,	.fasync = ecryptfs_fasync,	.splice_read = generic_file_splice_read,};