385 lines
10 KiB
C
Executable File
385 lines
10 KiB
C
Executable File
/**
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* eCryptfs: Linux filesystem encryption layer
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*
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* Copyright (C) 1997-2004 Erez Zadok
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* Copyright (C) 2001-2004 Stony Brook University
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* Copyright (C) 2004-2007 International Business Machines Corp.
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* Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
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* Michael C. Thompson <mcthomps@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*/
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#include <linux/file.h>
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#include <linux/poll.h>
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#include <linux/slab.h>
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#include <linux/mount.h>
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#include <linux/pagemap.h>
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#include <linux/security.h>
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#include <linux/compat.h>
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#include <linux/fs_stack.h>
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#include <linux/aio.h>
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#include "ecryptfs_kernel.h"
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/**
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* ecryptfs_read_update_atime
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*
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* generic_file_read updates the atime of upper layer inode. But, it
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* doesn't give us a chance to update the atime of the lower layer
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* inode. This function is a wrapper to generic_file_read. It
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* updates the atime of the lower level inode if generic_file_read
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* returns without any errors. This is to be used only for file reads.
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* The function to be used for directory reads is ecryptfs_read.
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*/
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static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
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struct iov_iter *to)
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{
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ssize_t rc;
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struct path *path;
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struct file *file = iocb->ki_filp;
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rc = generic_file_read_iter(iocb, to);
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/*
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* Even though this is a async interface, we need to wait
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* for IO to finish to update atime
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*/
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if (-EIOCBQUEUED == rc)
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rc = wait_on_sync_kiocb(iocb);
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if (rc >= 0) {
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path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
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touch_atime(path);
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}
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return rc;
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}
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struct ecryptfs_getdents_callback {
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struct dir_context ctx;
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struct dir_context *caller;
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struct super_block *sb;
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int filldir_called;
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int entries_written;
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};
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/* Inspired by generic filldir in fs/readdir.c */
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static int
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ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
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loff_t offset, u64 ino, unsigned int d_type)
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{
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struct ecryptfs_getdents_callback *buf =
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(struct ecryptfs_getdents_callback *)dirent;
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size_t name_size;
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char *name;
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int rc;
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buf->filldir_called++;
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rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
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buf->sb, lower_name,
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lower_namelen);
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if (rc) {
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printk(KERN_ERR "%s: Error attempting to decode and decrypt "
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"filename [%s]; rc = [%d]\n", __func__, lower_name,
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rc);
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goto out;
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}
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buf->caller->pos = buf->ctx.pos;
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rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
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kfree(name);
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if (!rc)
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buf->entries_written++;
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out:
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return rc;
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}
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/**
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* ecryptfs_readdir
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* @file: The eCryptfs directory file
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* @ctx: The actor to feed the entries to
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*/
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static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
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{
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int rc;
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struct file *lower_file;
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struct inode *inode = file_inode(file);
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struct ecryptfs_getdents_callback buf = {
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.ctx.actor = ecryptfs_filldir,
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.caller = ctx,
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.sb = inode->i_sb,
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};
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lower_file = ecryptfs_file_to_lower(file);
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lower_file->f_pos = ctx->pos;
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rc = iterate_dir(lower_file, &buf.ctx);
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ctx->pos = buf.ctx.pos;
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if (rc < 0)
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goto out;
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if (buf.filldir_called && !buf.entries_written)
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goto out;
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if (rc >= 0)
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fsstack_copy_attr_atime(inode,
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file_inode(lower_file));
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out:
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return rc;
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}
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struct kmem_cache *ecryptfs_file_info_cache;
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static int read_or_initialize_metadata(struct dentry *dentry)
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{
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struct inode *inode = dentry->d_inode;
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struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
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struct ecryptfs_crypt_stat *crypt_stat;
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int rc;
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crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
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mount_crypt_stat = &ecryptfs_superblock_to_private(
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inode->i_sb)->mount_crypt_stat;
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mutex_lock(&crypt_stat->cs_mutex);
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if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
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crypt_stat->flags & ECRYPTFS_KEY_VALID) {
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rc = 0;
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goto out;
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}
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rc = ecryptfs_read_metadata(dentry);
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if (!rc)
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goto out;
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if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
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crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
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| ECRYPTFS_ENCRYPTED);
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rc = 0;
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goto out;
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}
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if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
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!i_size_read(ecryptfs_inode_to_lower(inode))) {
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rc = ecryptfs_initialize_file(dentry, inode);
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if (!rc)
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goto out;
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}
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rc = -EIO;
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out:
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mutex_unlock(&crypt_stat->cs_mutex);
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return rc;
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}
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/**
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* ecryptfs_open
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* @inode: inode speciying file to open
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* @file: Structure to return filled in
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*
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* Opens the file specified by inode.
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*
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* Returns zero on success; non-zero otherwise
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*/
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static int ecryptfs_open(struct inode *inode, struct file *file)
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{
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int rc = 0;
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struct ecryptfs_crypt_stat *crypt_stat = NULL;
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struct dentry *ecryptfs_dentry = file->f_path.dentry;
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/* Private value of ecryptfs_dentry allocated in
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* ecryptfs_lookup() */
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struct ecryptfs_file_info *file_info;
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/* Released in ecryptfs_release or end of function if failure */
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file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
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ecryptfs_set_file_private(file, file_info);
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if (!file_info) {
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ecryptfs_printk(KERN_ERR,
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"Error attempting to allocate memory\n");
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rc = -ENOMEM;
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goto out;
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}
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crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
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mutex_lock(&crypt_stat->cs_mutex);
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if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
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ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
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/* Policy code enabled in future release */
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crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
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| ECRYPTFS_ENCRYPTED);
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}
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mutex_unlock(&crypt_stat->cs_mutex);
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rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
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if (rc) {
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printk(KERN_ERR "%s: Error attempting to initialize "
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"the lower file for the dentry with name "
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"[%pd]; rc = [%d]\n", __func__,
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ecryptfs_dentry, rc);
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goto out_free;
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}
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if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
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== O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
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rc = -EPERM;
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printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
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"file must hence be opened RO\n", __func__);
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goto out_put;
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}
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ecryptfs_set_file_lower(
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file, ecryptfs_inode_to_private(inode)->lower_file);
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if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
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ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
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mutex_lock(&crypt_stat->cs_mutex);
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crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
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mutex_unlock(&crypt_stat->cs_mutex);
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rc = 0;
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goto out;
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}
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rc = read_or_initialize_metadata(ecryptfs_dentry);
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if (rc)
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goto out_put;
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ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
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"[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
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(unsigned long long)i_size_read(inode));
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goto out;
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out_put:
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ecryptfs_put_lower_file(inode);
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out_free:
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kmem_cache_free(ecryptfs_file_info_cache,
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ecryptfs_file_to_private(file));
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out:
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return rc;
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}
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static int ecryptfs_flush(struct file *file, fl_owner_t td)
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{
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struct file *lower_file = ecryptfs_file_to_lower(file);
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if (lower_file->f_op->flush) {
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filemap_write_and_wait(file->f_mapping);
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return lower_file->f_op->flush(lower_file, td);
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}
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return 0;
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}
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static int ecryptfs_release(struct inode *inode, struct file *file)
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{
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ecryptfs_put_lower_file(inode);
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kmem_cache_free(ecryptfs_file_info_cache,
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ecryptfs_file_to_private(file));
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return 0;
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}
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static int
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ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
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{
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int rc;
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rc = filemap_write_and_wait(file->f_mapping);
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if (rc)
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return rc;
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return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
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}
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static int ecryptfs_fasync(int fd, struct file *file, int flag)
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{
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int rc = 0;
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struct file *lower_file = NULL;
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lower_file = ecryptfs_file_to_lower(file);
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if (lower_file->f_op->fasync)
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rc = lower_file->f_op->fasync(fd, lower_file, flag);
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return rc;
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}
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static long
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ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct file *lower_file = ecryptfs_file_to_lower(file);
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long rc = -ENOTTY;
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if (!lower_file->f_op->unlocked_ioctl)
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return rc;
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switch (cmd) {
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case FITRIM:
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case FS_IOC_GETFLAGS:
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case FS_IOC_SETFLAGS:
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case FS_IOC_GETVERSION:
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case FS_IOC_SETVERSION:
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rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
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fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
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return rc;
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default:
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return rc;
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}
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}
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#ifdef CONFIG_COMPAT
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static long
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ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct file *lower_file = ecryptfs_file_to_lower(file);
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long rc = -ENOIOCTLCMD;
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if (!lower_file->f_op->compat_ioctl)
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return rc;
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switch (cmd) {
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case FITRIM:
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case FS_IOC32_GETFLAGS:
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case FS_IOC32_SETFLAGS:
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case FS_IOC32_GETVERSION:
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case FS_IOC32_SETVERSION:
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rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
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fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
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return rc;
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default:
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return rc;
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}
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}
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#endif
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const struct file_operations ecryptfs_dir_fops = {
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.iterate = ecryptfs_readdir,
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.read = generic_read_dir,
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.unlocked_ioctl = ecryptfs_unlocked_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = ecryptfs_compat_ioctl,
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#endif
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.open = ecryptfs_open,
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.flush = ecryptfs_flush,
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.release = ecryptfs_release,
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.fsync = ecryptfs_fsync,
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.fasync = ecryptfs_fasync,
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.splice_read = generic_file_splice_read,
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.llseek = default_llseek,
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};
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const struct file_operations ecryptfs_main_fops = {
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.llseek = generic_file_llseek,
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.read = new_sync_read,
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.read_iter = ecryptfs_read_update_atime,
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.write = new_sync_write,
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.write_iter = generic_file_write_iter,
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.iterate = ecryptfs_readdir,
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.unlocked_ioctl = ecryptfs_unlocked_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = ecryptfs_compat_ioctl,
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#endif
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.mmap = generic_file_mmap,
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.open = ecryptfs_open,
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.flush = ecryptfs_flush,
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.release = ecryptfs_release,
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.fsync = ecryptfs_fsync,
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.fasync = ecryptfs_fasync,
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.splice_read = generic_file_splice_read,
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};
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