Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751347AbVKSEWg (ORCPT ); Fri, 18 Nov 2005 23:22:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751353AbVKSEWf (ORCPT ); Fri, 18 Nov 2005 23:22:35 -0500 Received: from c-67-182-200-232.hsd1.ut.comcast.net ([67.182.200.232]:24054 "EHLO sshock.homelinux.net") by vger.kernel.org with ESMTP id S1751345AbVKSEWd (ORCPT ); Fri, 18 Nov 2005 23:22:33 -0500 Date: Fri, 18 Nov 2005 21:22:29 -0700 From: Phillip Hellewell To: akpm@osdl.org Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@ftp.linux.org.uk, mike@halcrow.us, mhalcrow@us.ibm.com, mcthomps@us.ibm.com, yoder1@us.ibm.com Subject: [PATCH 10/12: eCryptfs] Mmap operations Message-ID: <20051119042229.GJ15747@sshock.rn.byu.edu> References: <20051119041130.GA15559@sshock.rn.byu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051119041130.GA15559@sshock.rn.byu.edu> X-URL: http://hellewell.homeip.net/ User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 38384 Lines: 1172 eCryptfs mmap operations. The bulk encryption and decryption takes place here. Signed-off-by: Phillip Hellewell Signed-off-by: Michael Halcrow Signed-off-by: Michael Thompson --- mmap.c | 1153 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 1153 insertions(+) --- linux-2.6.15-rc1-mm1/fs/ecryptfs/mmap.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.15-rc1-mm1-ecryptfs/fs/ecryptfs/mmap.c 2005-11-18 11:20:09.000000000 -0600 @@ -0,0 +1,1153 @@ +/** + * eCryptfs: Linux filesystem encryption layer + * This is where eCryptfs handles the bulk encryption and decryption, + * with upper-lower file index interpolations. + * + * Copyright (c) 1997-2003 Erez Zadok + * Copyright (c) 2001-2003 Stony Brook University + * Copyright (c) 2005 International Business Machines Corp. + * Author(s): Michael A. Halcrow + * + * 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 +#include +#include +#include +#include +#include +#include +#include "ecryptfs_kernel.h" + +static int ecryptfs_commit_write(struct file *file, struct page *page, + unsigned from, unsigned to); +static int ecryptfs_prepare_write(struct file *file, struct page *page, + unsigned from, unsigned to); + +kmem_cache_t *ecryptfs_lower_page_cache; + +static inline pgoff_t +record_idx(struct ecryptfs_crypt_stats *crypt_stats, pgoff_t idx) +{ + return (idx % crypt_stats->records_per_page); +} + +static inline pgoff_t +last_records_page_idx(struct ecryptfs_crypt_stats *crypt_stats, pgoff_t idx) +{ + pgoff_t lower_data_idx; + pgoff_t lower_record_idx; + + lower_data_idx = ecryptfs_pg_idx_to_lwr_pg_idx(crypt_stats, idx); + lower_record_idx = record_idx(crypt_stats, idx); + return (lower_data_idx - lower_record_idx - 1); +} + +/** + * Get one page from cache or lower f/s, return error otherwise. + * + * @return Unlocked and up-to-date page (if ok), with increased + * refcnt. + */ +static struct page *ecryptfs_get1page(struct file *file, int index) +{ + struct page *page; + struct dentry *dentry; + struct inode *inode; + struct address_space *mapping; + int rc; + + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + dentry = file->f_dentry; + inode = dentry->d_inode; + mapping = inode->i_mapping; + if (index < 0) { + ecryptfs_printk(1, KERN_ERR, "BUG: index=%d\n", index); + page = ERR_PTR(-EIO); + goto out; + } + page = read_cache_page(mapping, index, + (filler_t *) mapping->a_ops->readpage, + (void *)file); + if (IS_ERR(page)) + goto out; + wait_on_page_locked(page); + if (!PageUptodate(page)) { + lock_page(page); + rc = mapping->a_ops->readpage(file, page); + if (rc) { + page = ERR_PTR(rc); + goto out; + } + wait_on_page_locked(page); + if (!PageUptodate(page)) { + page = ERR_PTR(-EIO); + goto out; + } + } +out: + ecryptfs_printk(1, KERN_NOTICE, "Exit\n"); + return page; +} + +/** + * Write a specified number of zero's to a page. + * + * N.B. (start + num_zeros) _must_ be less than or equal to PAGE_CACHE_SIZE + * + * @param file The ecryptfs file + * @param index The index in which we are writing + * @param start The position after the last block of data + * @param num_zeros The number of zeros to write + */ +static +int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros) +{ + int rc = 0; + struct page *tmp_page; + + ecryptfs_printk(1, KERN_NOTICE, "Enter; index = [%lu], start offset = " + "[%d] num_zeros = [%d]\n", index, start, num_zeros); + tmp_page = ecryptfs_get1page(file, index); + if (IS_ERR(tmp_page)) { + ecryptfs_printk(0, KERN_ERR, "Error getting page at index " + "[%lu]\n", index); + rc = PTR_ERR(tmp_page); + goto out; + } + kmap(tmp_page); + memset(((char *)page_address(tmp_page) + start), 0, num_zeros); + rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "Error preparing to write zero's " + "to remainder of page at index [%lu]\n", index); + kunmap(tmp_page); + page_cache_release(tmp_page); + goto out; + } + rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros); + if (rc < 0) { + ecryptfs_printk(0, KERN_ERR, "Error attempting to write zero's " + "to remainder of page at index [%lu]\n", index); + kunmap(tmp_page); + page_cache_release(tmp_page); + goto out; + } + rc = 0; + kunmap(tmp_page); + page_cache_release(tmp_page); +out: + ecryptfs_printk(1, KERN_NOTICE, "Exit\n"); + return rc; +} + +/** + * Function for handling creation of holes when lseek-ing past the end + * of the file and then writing some data. + * + * N.B. + * This function does NOT support shrinking, only growing a file. + * The code _will_ BUG() if this requirement is not met. + * The new_length _myust_ be greater than the current length. + * + * @param file The ecryptfs file + * @param new_length The new length of the data in the underlying file; + * everything between the prior end of the file and the new + * end of the file will be filled with zero's. + * N.B. new_length must be greater than current length + * @return Zero on success; non-zero otherwise + */ +int ecryptfs_fill_zeros(struct file *file, loff_t new_length) +{ + int rc = 0; + struct dentry *dentry = file->f_dentry; + struct inode *inode = dentry->d_inode; + pgoff_t old_end_page_index = 0; + pgoff_t index = old_end_page_index; + int old_end_pos_in_page = -1; + pgoff_t new_end_page_index; + int new_end_pos_in_page; + loff_t cur_length = i_size_read(inode); + + ecryptfs_printk(1, KERN_NOTICE, "Enter; inode->i_size = [%llu]; " + "new_length = [%llu]\n", cur_length, new_length); + /* Sanity check */ + if (cur_length >= new_length) { + ecryptfs_printk(0, KERN_ERR, "Called with new_length less than " + "or equal to the current length, this is " + "against function restrictions!\n"); + BUG(); + } + /* N.B. Notes on index calculations + * It is important to note that the size of the file will always be 1 + * greater than the last block of data's position added to the data's + * index shifted by the page cache size. + * size = index * PAGE_CACHE_SIZE + pos + 1 + * + * Example, a file with 1 block of data in the 0th index at the 0th + * position will be a file of size 1. Likewise, a file of 100 blocks + * of data will have it's last block in the 99th position. + * + * Therefore, a file of size page with PAGE_CACHE_SIZE blocks of data + * will have its last block of data in the (PAGE_CACHE_SIZE-1)th + * position, in the 0th index. A file with (PAGE_CACHE_SIZE + 1) blocks + * of data will have its last block of data in the 0th position of the + * 1st index. This calculation can be shown as: + * position = (size - 1) & ~PAGE_CACHE_MASK + * index = (size - 1) >> PAGE_CACHE_SHIFT + * + * Example: + * PAGE_CACHE_SHIFT = 12 + * PAGE_CACHE_SIZE = (1UL << PAGE_CACHE_SHIFT) [or 4096] + * PAGE_CACHE_MASK = (~(PAGE_CACHE_SIZE-1)) [or ~(4096-1)] + * + * A size of 4095 yields: + * position = (4095 - 1) & ~PAGE_CACHE_MASK => 4094 + * index = (4095 - 1) >> 12 => 0 + * + * A size of 4096 yields: + * position = (4096 - 1) & ~PAGE_CACHE_MASK => 4095 + * index = (4096 - 1) >> 12 => 0 + * + * A size of 4097 yields: + * position = (4097 - 1) & ~PAGE_CACHE_MASK => 0 + * index = (4097 - 1) >> 12 => 1 + * + * From these examples, you can see that the logic that a + * file's last block of data is at the (size - 1)th position + * follows. + * + * A 0-length file is by this logic, undefined if positions + * and indicies are required to be positive integers. However, + * this is intuative, as a 0-length file has no data which to + * give a position and index to. However, to make our + * calculations work, we will use the default value of -1 if + * the size is 0. The following will apply: + * old size = 0 + * old position = -1 + * old index = 0 + * new size = 1 + * new position = 0 + * new index = 0 + * + * write_zeros(file,0,(-1+1) => 0, ((size-1) - (-1)) => size) + * + * Therefore, if the current size of the file is 0, then + * setting our index and position to -1 will result in valid + * calculations for the new index and position for the new + * size. + */ + if (cur_length != 0) { + index = old_end_page_index = + ((cur_length - 1) >> PAGE_CACHE_SHIFT); + old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK); + } + new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT); + new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK); + + ecryptfs_printk(1, KERN_NOTICE, "old_end_page_index = [%lu]; " + "old_end_pos_in_page = [%d]; " + "new_end_page_index = [%lu]; " + "new_end_pos_in_page = [%d]\n", + old_end_page_index, old_end_pos_in_page, + new_end_page_index, new_end_pos_in_page); + if (old_end_page_index == new_end_page_index) { + /* Start and end are in the same page; we just need to + * set a portion of the existing page to zero's */ + rc = write_zeros(file, index, (old_end_pos_in_page + 1), + (new_end_pos_in_page - old_end_pos_in_page)); + if (rc) + ecryptfs_printk(0, KERN_ERR, "write_zeros(file=[%p], " + "index=[%lu], old_end_pos_in_page=[d], " + "(PAGE_CACHE_SIZE - new_end_pos_in_page" + "=[%d]" + ")=[d]) returned [%d]\n", file, index, + old_end_pos_in_page, + new_end_pos_in_page, + (PAGE_CACHE_SIZE - new_end_pos_in_page), + rc); + goto out; + } + /* Else, new position is outside of the current index. + * Fill remainder of current page with zeros. + * For each page after that page, will entire page with zeros. + * Upon reaching new last page, write as many zeros as required + * to fullfil the new size. */ + /* Fill the remainder of the previous last page with zeros */ + rc = write_zeros(file, index, (old_end_pos_in_page + 1), + ((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page)); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "write_zeros(file=[%p], " + "index=[%lu], old_end_pos_in_page=[d], " + "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) " + "returned [%d]\n", file, index, + old_end_pos_in_page, + (PAGE_CACHE_SIZE - old_end_pos_in_page), rc); + goto out; + } + index++; + while (index < new_end_page_index) { + /* Fill all intermediate pages with zeros */ + rc = write_zeros(file, index, 0, PAGE_CACHE_SIZE); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "write_zeros(file=[%p], " + "index=[%lu], old_end_pos_in_page=[d], " + "(PAGE_CACHE_SIZE - new_end_pos_in_page" + "=[%d]" + ")=[d]) returned [%d]\n", file, index, + old_end_pos_in_page, + new_end_pos_in_page, + (PAGE_CACHE_SIZE - new_end_pos_in_page), + rc); + goto out; + } + index++; + } + /* Fill the portion at the beginning of the last new page with + * zero's */ + rc = write_zeros(file, index, 0, (new_end_pos_in_page + 1)); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "write_zeros(file=" + "[%p], index=[%lu], 0, " + "new_end_pos_in_page=[%d]" + "returned [%d]\n", file, index, + new_end_pos_in_page, rc); + goto out; + } +out: + ecryptfs_printk((rc == 0 ? 1 : 0), KERN_NOTICE, "Exit; rc = [%d]\n", + rc); + return rc; +} + +/** + * @param lower_file Can be NULL + * @return Zero on success + */ +static int +ecryptfs_read_rotate_write_iv(char *iv, struct inode *inode, + int lower_iv_idx, struct file *lower_file, + struct page *page) +{ + int rc = 0; + pgoff_t records_page_index; + struct ecryptfs_crypt_stats *crypt_stats; + struct page *records_page; + char *records_virt; + int lower_file_needs_fput = 0; + struct address_space_operations *lower_a_ops; + struct inode *lower_inode; + + crypt_stats = &(ECRYPTFS_INODE_TO_PRIVATE(inode)->crypt_stats); + lower_inode = ECRYPTFS_INODE_TO_LOWER(inode); + lower_a_ops = lower_inode->i_mapping->a_ops; + records_page_index = last_records_page_idx(crypt_stats, page->index); + ecryptfs_printk(1, KERN_NOTICE, "records_page_index = [%lu]\n", + records_page_index); + records_page = grab_cache_page(lower_inode->i_mapping, + records_page_index); + if (!records_page) { + ecryptfs_printk(0, KERN_ERR, "records_page == NULL " + "after grab_cache_page at index [%lu]" + "\n", records_page_index); + rc = -EIO; + goto out; + } + /* TODO: Assume encrypted only for version 0.1 */ + ecryptfs_printk(1, KERN_NOTICE, "lower_iv_idx = [%d]\n", lower_iv_idx); + records_virt = kmap(records_page); + if (!records_virt) { + rc = -ENOMEM; + ecryptfs_printk(1, KERN_NOTICE, "Error in kmap\n"); + goto out_unlock_and_release; + } + if (!lower_file) { + struct dentry *lower_dentry; + struct vfsmount *lower_mnt; + + if (!lower_inode->i_dentry.next) { + rc = -EINVAL; + ecryptfs_printk(1, KERN_NOTICE, "No dentry for " + "lower_inode\n"); + goto out_unmap; + } + lower_dentry = list_entry(lower_inode->i_dentry.next, + struct dentry, d_alias); + mntget(ECRYPTFS_SUPERBLOCK_TO_PRIVATE(inode->i_sb)->lower_mnt); + lower_mnt = + ECRYPTFS_SUPERBLOCK_TO_PRIVATE(inode->i_sb)->lower_mnt; + lower_file = dentry_open(lower_dentry, lower_mnt, FMODE_READ); + if (IS_ERR(lower_file)) { + rc = PTR_ERR(lower_file); + ecryptfs_printk(0, KERN_ERR, + "Error opening dentry; rc = [%i]\n", + rc); + mntput(ECRYPTFS_SUPERBLOCK_TO_PRIVATE(inode->i_sb)->lower_mnt); + goto out_unmap; + } + lower_file_needs_fput = 1; + } + rc = lower_a_ops->prepare_write(lower_file, records_page, lower_iv_idx, + (lower_iv_idx + crypt_stats->iv_bytes)); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "Error in lower prepare_write() " + "call: rc = [%d]\n", rc); + goto out_unmap; + } + down(&crypt_stats->iv_sem); + ecryptfs_rotate_iv(crypt_stats->iv); + memcpy(iv, crypt_stats->iv, crypt_stats->iv_bytes); + up(&crypt_stats->iv_sem); + memcpy(records_virt + lower_iv_idx, crypt_stats->iv, + crypt_stats->iv_bytes); + rc = lower_a_ops->commit_write(lower_file, records_page, lower_iv_idx, + (lower_iv_idx + crypt_stats->iv_bytes)); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "Error in lower commit_write() " + "call: rc = [%d]\n", rc); + goto out_unmap; + } + lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; + ecryptfs_printk(1, KERN_NOTICE, "Unlocking page with index = " + "[%lu]\n", records_page->index); +out_unmap: + kunmap(records_page); +out_unlock_and_release: + unlock_page(records_page); + page_cache_release(records_page); + ecryptfs_printk(1, KERN_NOTICE, "After committing IV write, " + "lower_inode->i_blocks = [%lu]\n", + lower_inode->i_blocks); +out: + if (lower_file_needs_fput) + fput(lower_file); + return rc; +} + +/** + * @return Zero on success; negative on error + */ +static int encrypt_page(struct ecryptfs_crypt_stats *crypt_stats, + struct page *page, struct page *lower_page, char *iv) +{ + int rc = 0; + + ecryptfs_printk(1, KERN_NOTICE, "Calling do_encrypt_page()\n"); + ecryptfs_printk(1, KERN_NOTICE, "Encrypting page with iv:\n"); + if (unlikely(ecryptfs_verbosity > 0)) + ecryptfs_dump_hex(iv, crypt_stats->iv_bytes); + ecryptfs_printk(1, KERN_NOTICE, "First 8 bytes before " + "encryption:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex((char *)page_address(page), 8); + rc = do_encrypt_page_offset(crypt_stats, lower_page, 0, + page, 0, crypt_stats->extent_size, iv); + ecryptfs_printk(1, KERN_NOTICE, "Encrypted [%d] bytes\n", rc); + ecryptfs_printk(1, KERN_NOTICE, "First 8 bytes after " "encryption:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex((char *)page_address(lower_page), 8); + if (rc > 0) + rc = 0; + return rc; +} + +/** + * @param page Page that is locked before this call is made + */ +static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc) +{ + int rc = -EIO; + int err = 0; + unsigned long lower_index; + struct inode *inode; + struct inode *lower_inode; + struct page *lower_page; + char *kaddr, *lower_kaddr; + struct ecryptfs_crypt_stats *crypt_stats; + + ecryptfs_printk(1, KERN_NOTICE, "Enter; page->index = [%ld]; " + "page->mapping->host = [%p]\n", page->index, + page->mapping->host); + inode = page->mapping->host; + crypt_stats = &(ECRYPTFS_INODE_TO_PRIVATE(inode)->crypt_stats); + lower_inode = ECRYPTFS_INODE_TO_LOWER(inode); + lower_index = ecryptfs_pg_idx_to_lwr_pg_idx(crypt_stats, page->index); + ecryptfs_printk(1, KERN_NOTICE, "Grab lower_idx = [%ld]\n", + lower_index); + lower_page = grab_cache_page(lower_inode->i_mapping, lower_index); + if (!lower_page) { + rc = -ENOMEM; + goto out; + } + kaddr = (char *)kmap(page); + if (!kaddr) { + rc = -ENOMEM; + goto out; + } + lower_kaddr = (char *)kmap(lower_page); + if (!lower_kaddr) { + rc = -ENOMEM; + goto out; + } + if (crypt_stats->encrypted) { + char iv[ECRYPTFS_MAX_IV_BYTES]; + int record_byte_offset; + /* TODO: HMAC: Include HMAC bytes in the record size */ + record_byte_offset = (record_idx(crypt_stats, page->index) + * crypt_stats->iv_bytes); + rc = ecryptfs_read_rotate_write_iv(iv, inode, + record_byte_offset, NULL, + page); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "Error rotating " + "IV; write failure. Assuming " + "IV page corruption; writing " + "0's to associated data extent" + ".\n"); + memset(lower_kaddr, 0, crypt_stats->extent_size); + err = -EIO; + goto do_lower_write; + } + ecryptfs_printk(1, KERN_NOTICE, "Encrypting page with iv:\n"); + if (unlikely(ecryptfs_verbosity > 0)) + ecryptfs_dump_hex(iv, crypt_stats->iv_bytes); + err = encrypt_page(crypt_stats, page, lower_page, iv); + if (err) + ecryptfs_printk(0, KERN_WARNING, "Error encrypting " + "page (upper index [%llu])\n", + page->index); + } else + memcpy(lower_kaddr, kaddr, crypt_stats->extent_size); +do_lower_write: + kunmap(page); + kunmap(lower_page); + rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc); + if (rc) + ecryptfs_printk(0, KERN_ERR, "Error calling lower writepage(); " + "rc = [%d]\n", rc); + lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; + page_cache_release(lower_page); + if (rc) + ClearPageUptodate(page); + else + SetPageUptodate(page); + unlock_page(page); +out: + if (err) + rc = err; + ecryptfs_printk(1, KERN_NOTICE, "Exit; rc = [%d]\n", rc); + return rc; +} + +/** + * Reads the data from the lower file file at index lower_page_index + * and copies that data into page. + * + * @param page Page to fill + * @param lower_page_index Index of the page in the lower file to get + */ +static int ecryptfs_do_readpage(struct file *file, struct page *page, + pgoff_t lower_page_index) +{ + int rc = -EIO; + struct dentry *dentry; + struct file *lower_file; + struct dentry *lower_dentry; + struct inode *inode; + struct inode *lower_inode; + char *page_data; + struct page *lower_page = NULL; + char *lower_page_data; + struct address_space_operations *lower_a_ops; + + ecryptfs_printk(1, KERN_NOTICE, "Enter; lower_page_index = [%lu]\n", + lower_page_index); + dentry = file->f_dentry; + if (NULL == ECRYPTFS_FILE_TO_PRIVATE_SM(file)) { + rc = -ENOENT; + ecryptfs_printk(0, KERN_ERR, "No lower file info\n"); + goto out; + } + lower_file = ECRYPTFS_FILE_TO_LOWER(file); + lower_dentry = ECRYPTFS_DENTRY_TO_LOWER(dentry); + inode = dentry->d_inode; + lower_inode = ECRYPTFS_INODE_TO_LOWER(inode); + lower_a_ops = lower_inode->i_mapping->a_ops; + lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index, + (filler_t *) lower_a_ops->readpage, + (void *)lower_file); + if (IS_ERR(lower_page)) { + rc = PTR_ERR(lower_page); + lower_page = NULL; + ecryptfs_printk(0, KERN_ERR, "Error reading from page cache\n"); + goto out; + } + wait_on_page_locked(lower_page); + if (!PageUptodate(lower_page)) { + lock_page(lower_page); + rc = lower_a_ops->readpage(lower_file, lower_page); + if (rc) { + lower_page = NULL; + rc = -EIO; + ecryptfs_printk(0, KERN_ERR, "Error reading lower " + "page at index=[%lu]\n", + lower_page_index); + goto out; + } + wait_on_page_locked(lower_page); + if (!PageUptodate(lower_page)) { + rc = -EIO; + ecryptfs_printk(0, KERN_ERR, "Error reading lower " + "page at index=[%lu]\n", + lower_page_index); + goto out; + } + } + page_data = (char *)kmap(page); + if (!page_data) { + rc = -ENOMEM; + ecryptfs_printk(0, KERN_ERR, "Error mapping page\n"); + goto out; + } + lower_page_data = (char *)kmap(lower_page); + if (!lower_page_data) { + rc = -ENOMEM; + ecryptfs_printk(0, KERN_ERR, "Error mapping page\n"); + kunmap(page); + goto out; + } + /* TODO: Copy sub-page amount of data? */ + memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE); + kunmap(lower_page); + kunmap(page); + rc = 0; + out: + if (likely(lower_page)) + page_cache_release(lower_page); + if (rc == 0) + SetPageUptodate(page); + else + ClearPageUptodate(page); + ecryptfs_printk(1, KERN_NOTICE, "Exit; rc = [%d]\n", rc); + return rc; +} + +/* Action descriptor for decrypt_page() */ +#define ECRYPTFS_ACTION_COPY 0 +#define ECRYPTFS_ACTION_DECRYPT 1 + +/** + * Decrypt a page of data + * + * @return Zero on success + */ +static int decrypt_page(struct ecryptfs_crypt_stats *crypt_stats, + struct file *file, char *iv, struct page *page, + pgoff_t lower_page_index, int decrypt) +{ + int rc = 0; + char *lower_page_encrypted_virt; + struct page *lower_page_encrypted; + int decrypt_to; + + ecryptfs_printk(1, KERN_NOTICE, "Enter; lower_page_index = [%d]\n", + lower_page_index); + lower_page_encrypted_virt = + kmem_cache_alloc(ecryptfs_lower_page_cache, SLAB_KERNEL); + if (!lower_page_encrypted_virt) { + rc = -ENOMEM; + ecryptfs_printk(0, KERN_ERR, "Error getting page for " + "encrypted lower page\n"); + ClearPageUptodate(page); + goto out; + } + lower_page_encrypted = virt_to_page(lower_page_encrypted_virt); + rc = ecryptfs_do_readpage(file, lower_page_encrypted, lower_page_index); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "Error reading lower encrypted " + "page\n"); + ClearPageUptodate(page); + goto out; + } + ecryptfs_printk(1, KERN_NOTICE, "Decrypting page with iv:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex(iv, crypt_stats->iv_bytes); + ecryptfs_printk(1, KERN_NOTICE, "Using session key encryption key:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex(crypt_stats->key, + crypt_stats->key_size_bits / 8); + decrypt_to = crypt_stats->extent_size; + ecryptfs_printk(1, KERN_NOTICE, "Decrypting to: [%d]\n", decrypt_to); + ecryptfs_printk(1, KERN_NOTICE, "First 8 bytes before decryption:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex((char *)page_address(lower_page_encrypted), + 8); + if (decrypt) + do_decrypt_page_offset(crypt_stats, page, + 0, lower_page_encrypted, + 0, decrypt_to, iv); + else + memcpy(page, lower_page_encrypted_virt, decrypt_to); + ecryptfs_printk(1, KERN_NOTICE, "First 8 bytes after decryption:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex((char *)page_address(page), 8); + kmem_cache_free(ecryptfs_lower_page_cache, lower_page_encrypted_virt); +out: + ecryptfs_printk(1, KERN_NOTICE, "Exit; rc = [%d]\n", rc); + return rc; +} + +/** + * Read in a page + * + * @param file This is an ecryptfs file + * @param page ecryptfs associated page to stick the read data into + * @return Zero on success; non-zero on error + */ +static int ecryptfs_readpage(struct file *file, struct page *page) +{ + int rc = 0; + struct ecryptfs_crypt_stats *crypt_stats = NULL; + char iv[ECRYPTFS_MAX_IV_BYTES]; + int iv_is_nonzero = 0; + char *records_virt; + struct page *records_page; + int record_byte_offset; + int iv_byte_offset; + int i; + pgoff_t records_page_index; + pgoff_t lower_page_index; + + ecryptfs_printk(1, KERN_NOTICE, "Enter; page->index = [%ld]\n", + page->index); + ASSERT(file && file->f_dentry && file->f_dentry->d_inode); + crypt_stats = + &ECRYPTFS_INODE_TO_PRIVATE(file->f_dentry->d_inode)->crypt_stats; + /* If the file is neither encrypted nor HMAC-verified, then we + * have passthrough mode. */ + if (!crypt_stats || !crypt_stats->encrypted) { + ecryptfs_printk(1, KERN_NOTICE, + "Passing through unencrypted page\n"); + rc = ecryptfs_do_readpage(file, page, page->index); + goto out; + } + /* The file is encrypted, hmac verified, or both. */ + ecryptfs_printk(1, KERN_NOTICE, + "crypt_stats->iv_bytes = [%d]\n", + crypt_stats->iv_bytes); + ecryptfs_printk(1, KERN_NOTICE, + "crypt_stats->records_per_page = [%d]\n", + crypt_stats->records_per_page); + + /* Get the relevant IV/HMAC page */ + records_page_index = last_records_page_idx(crypt_stats, page->index); + ecryptfs_printk(1, KERN_NOTICE, "records_page_index = [%lu]\n", + records_page_index); + records_virt = (char *)__get_free_page(GFP_KERNEL); + if (!records_virt) { + ecryptfs_printk(0, KERN_ERR, "Error getting free page"); + rc = -ENOMEM; + ClearPageUptodate(page); + goto out; + } + records_page = virt_to_page(records_virt); + rc = ecryptfs_do_readpage(file, records_page, records_page_index); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "Error reading IV/HMAC page"); + ClearPageUptodate(page); + goto out; + } + /* TODO: HMAC: Include HMAC bytes in the record size */ + record_byte_offset = (record_idx(crypt_stats, page->index) + * crypt_stats->iv_bytes); + iv_byte_offset = -1; + if (crypt_stats->encrypted) { + iv_byte_offset = record_byte_offset; + iv_is_nonzero = 0; + for (i = 0; i < crypt_stats->iv_bytes; i++) + iv_is_nonzero |= (records_virt + iv_byte_offset)[i]; + memcpy(iv, (records_virt + iv_byte_offset), + crypt_stats->iv_bytes); + } + ecryptfs_printk(1, KERN_NOTICE, "record_byte_offset = [%d]\n", + record_byte_offset); + ecryptfs_printk(1, KERN_NOTICE, "iv_byte_offset = [%d]\n", + iv_byte_offset); + free_page((unsigned long)records_virt); + lower_page_index = ecryptfs_pg_idx_to_lwr_pg_idx(crypt_stats, + page->index); + ecryptfs_printk(1, KERN_NOTICE, "lower_page_index = [%lu]\n", + lower_page_index); + ecryptfs_printk(1, KERN_NOTICE, "iv_is_nonzero = [%d]\n", + iv_is_nonzero); + if (crypt_stats->encrypted && iv_is_nonzero) { + rc = decrypt_page(crypt_stats, file, iv, page, + lower_page_index, ECRYPTFS_ACTION_DECRYPT); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "Error decrypting " + "page; rc = [%d]\n", rc); + goto out; + } + } else { + ecryptfs_printk(1, KERN_NOTICE, + "Passing through unencrypted page\n"); + rc = ecryptfs_do_readpage(file, page, lower_page_index); + } + SetPageUptodate(page); +out: + ecryptfs_printk(1, KERN_NOTICE, "Unlocking page with index = [%lu]\n", + page->index); + unlock_page(page); + ecryptfs_printk(1, KERN_NOTICE, "Exit; rc = [%d]\n", rc); + return rc; +} + +static void fill_zeros_to_end_of_page(struct page *page, unsigned to) +{ + struct inode *inode = page->mapping->host; + int end_byte_in_page; + char *page_virt; + + if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) { + end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE; + if (to > end_byte_in_page) + end_byte_in_page = to; + page_virt = kmap(page); + if (!page_virt) { + goto out; + } + memset((page_virt + end_byte_in_page), 0, + (PAGE_CACHE_SIZE - end_byte_in_page)); + kunmap(page); + } +out: + return; +} + +static int ecryptfs_prepare_write(struct file *file, struct page *page, + unsigned from, unsigned to) +{ + int err = 0; + + ecryptfs_printk(1, KERN_NOTICE, "Enter; page->index = [%lu]; from = " + "[%d]; to = [%d]\n", page->index, from, to); + kmap(page); + if (from == 0 && to == PAGE_CACHE_SIZE) + goto out; /* If we are writing a full page, it will be + up to date. */ + if (!PageUptodate(page)) + err = ecryptfs_do_readpage(file, page, page->index); +out: + return err; +} + +/** + * @return Zero on success + */ +int +ecryptfs_write_inode_size_to_header(struct file *lower_file, + struct inode *lower_inode, + struct inode *inode) +{ + int rc = 0; + struct page *header_page; + char *header_virt; + struct address_space_operations *lower_a_ops; + unsigned long long file_size; + + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + header_page = grab_cache_page(lower_inode->i_mapping, 0); + if (!header_page) { + rc = -EINVAL; + ecryptfs_printk(0, KERN_ERR, "grab_cache_page for header page " + "failed\n"); + goto out; + } + header_virt = kmap(header_page); + lower_a_ops = lower_inode->i_mapping->a_ops; + rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8); + file_size = (unsigned long long)i_size_read(inode); + memcpy(header_virt, &file_size, 8); + rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8); + if (rc < 0) + ecryptfs_printk(0, KERN_ERR, "Error commiting header page " + "write\n"); + kunmap(header_page); + ecryptfs_printk(1, KERN_NOTICE, "Unlocking page with index = [%lu]\n", + header_page->index); + unlock_page(header_page); + page_cache_release(header_page); + lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; + mark_inode_dirty_sync(inode); +out: + ecryptfs_printk(1, KERN_NOTICE, "Exit; rc = [%d]\n", rc); + return rc; +} + +/** + * This is where we encrypt the data and pass the encrypted data to + * the lower filesystem. In OpenPGP-compatible mode, we operate on + * entire underlying packets. + * + * @param file The eCryptfs file object + * @param page The eCryptfs page + * @param from Ignored (we rotate the page IV on each write) + * @param to Ignored + * @return + */ +static int ecryptfs_commit_write(struct file *file, struct page *page, + unsigned from, unsigned to) +{ + int rc = -ENOMEM; + struct inode *inode; + struct inode *lower_inode; + struct page *lower_page = NULL; + struct file *lower_file = NULL; + loff_t pos; + unsigned bytes = to - from; + struct ecryptfs_crypt_stats *crypt_stats; + pgoff_t lower_page_index; + struct address_space_operations *lower_a_ops; + struct dentry *ecryptfs_dentry; + + ecryptfs_printk(1, KERN_NOTICE, + "Enter; page->index = [%lu]; from = [%d]; to = [%d]\n", + page->index, from, to); + ecryptfs_dentry = file->f_dentry; + inode = page->mapping->host; + lower_inode = ECRYPTFS_INODE_TO_LOWER(inode); + down(&lower_inode->i_sem); + if (!(lower_inode->i_mapping + && lower_inode->i_mapping->a_ops + && lower_inode->i_mapping->a_ops->prepare_write + && lower_inode->i_mapping->a_ops->commit_write)) { + ecryptfs_printk(0, KERN_ERR, + "a_ops of lower inode not valid\n"); + rc = -EINVAL; + goto out; + } + lower_a_ops = lower_inode->i_mapping->a_ops; + ASSERT(file && file->f_dentry && file->f_dentry->d_inode); + crypt_stats = + &ECRYPTFS_INODE_TO_PRIVATE(file->f_dentry->d_inode)->crypt_stats; + if (NULL != ECRYPTFS_FILE_TO_PRIVATE(file)) + lower_file = ECRYPTFS_FILE_TO_LOWER(file); + if (!crypt_stats) { + rc = -EINVAL; + goto out; + } + + rc = ecryptfs_init_crypt_ctx(crypt_stats); + if (rc) + ecryptfs_printk(1, KERN_NOTICE, "Problem with " + "initializing crypto context\n"); + if (crypt_stats->new_file) { + struct page *header_page; + char *header_virt; + + crypt_stats->new_file = 0; + header_page = grab_cache_page(lower_inode->i_mapping, 0); + if (!header_page) { + rc = -EINVAL; + ecryptfs_printk(0, KERN_ERR, "grab_cache_page for " + "header page failed\n"); + goto out; + } + header_virt = kmap(header_page); + rc = lower_a_ops->prepare_write(lower_file, header_page, + 0, crypt_stats->extent_size); + rc = ecryptfs_write_headers_virt(header_virt, crypt_stats, + ecryptfs_dentry, + ECRYPTFS_FILE_VERSION); + if (rc) { + ecryptfs_printk(0, KERN_WARNING, "Error generating " + "header; rc = [%d]\n", rc); + rc = -EIO; + goto out; + } + memset(header_virt, 0, 8); + rc = lower_a_ops->commit_write(lower_file, header_page, + 0, crypt_stats->extent_size); + if (rc < 0) + ecryptfs_printk(0, KERN_ERR, "Error commiting header " + "page write\n"); + kunmap(header_page); + ecryptfs_printk(1, KERN_NOTICE, + "Unlocking header page with index = " "[%lu]\n", + header_page->index); + unlock_page(header_page); + page_cache_release(header_page); + if (rc < 0) + goto out; + rc = 0; + ecryptfs_printk(1, KERN_NOTICE, "lower_inode->i_blocks = " + "[%lu]\n", lower_inode->i_blocks); + i_size_write(inode, 0); + lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; + mark_inode_dirty_sync(inode); + } else + ecryptfs_printk(1, KERN_NOTICE, "Not a new file\n"); + /* Translate the page index */ + lower_page_index = ecryptfs_pg_idx_to_lwr_pg_idx(crypt_stats, + page->index); + ecryptfs_printk(1, KERN_NOTICE, "lower_page_index = [%lu]\n", + lower_page_index); + lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index); + if (!lower_page) { + ecryptfs_printk(0, KERN_ERR, "grab_cache_page for " + "lower_page_index=[%lu] failed\n", + lower_page_index); + goto out; + } + kmap(lower_page); + rc = lower_a_ops->prepare_write(lower_file, lower_page, + 0, crypt_stats->extent_size); + if (rc) + goto out_unlock_lower; + fill_zeros_to_end_of_page(page, to); + if (!crypt_stats->encrypted) { + /* TODO: aops */ + memcpy((char *)page_address(lower_page), + (char *)page_address(page), crypt_stats->extent_size); + } else { + /* The file is either encrypted or HMAC'd */ + char iv[ECRYPTFS_MAX_IV_BYTES]; + int record_byte_offset; + ecryptfs_printk(1, KERN_NOTICE, + "crypt_stats->iv_bytes = [%d]\n", + crypt_stats->iv_bytes); + /* TODO: HMAC: Include HMAC bytes in the record size */ + record_byte_offset = (record_idx(crypt_stats, page->index) + * crypt_stats->iv_bytes); + rc = ecryptfs_read_rotate_write_iv(iv, inode, + record_byte_offset, + lower_file, page); + if (rc) { + ecryptfs_printk(0, KERN_ERR, "Error rotating IV\n"); + goto out_unlock_lower; + } + ecryptfs_printk(1, KERN_NOTICE, "Encrypting page with iv:\n"); + if (unlikely(ecryptfs_verbosity > 0)) + ecryptfs_dump_hex(iv, crypt_stats->iv_bytes); + rc = encrypt_page(crypt_stats, page, lower_page, iv); + if (rc) { + ecryptfs_printk(0, KERN_WARNING, "Error encrypting " + "page (upper index [%llu])\n", + page->index); + goto out; + } + } + rc = lower_a_ops->commit_write(lower_file, lower_page, 0, + crypt_stats->extent_size); + if (rc < 0) { + ecryptfs_printk(0, KERN_ERR, + "Error committing write; rc = [%d]\n", rc); + goto out_unlock_lower; + } + rc = bytes; + inode->i_blocks = lower_inode->i_blocks; + pos = (page->index << PAGE_CACHE_SHIFT) + to; + if (pos > i_size_read(inode)) { + i_size_write(inode, pos); + ecryptfs_printk(1, KERN_NOTICE, "Expanded file size to " + "[%lld]\n", i_size_read(inode)); + } + ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode); + lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; + mark_inode_dirty_sync(inode); + +out_unlock_lower: + kunmap(lower_page); + ecryptfs_printk(1, KERN_NOTICE, + "Unlocking lower page with index = [%lu]\n", + lower_page->index); + unlock_page(lower_page); + page_cache_release(lower_page); + kunmap(page); /* mapped in prepare_write */ +out: + if (rc < 0) + ClearPageUptodate(page); + else + SetPageUptodate(page); + up(&lower_inode->i_sem); + ecryptfs_printk(1, KERN_NOTICE, "Exit; rc = [%d]\n", rc); + return rc; +} + +static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block) +{ + int rc = 0; + struct inode *inode; + struct inode *lower_inode; + + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + inode = (struct inode *)mapping->host; + lower_inode = ECRYPTFS_INODE_TO_LOWER(inode); + if (lower_inode->i_mapping->a_ops->bmap) + rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping, + block); + return rc; +} + +/** + * This function is copied verbatim from mm/filemap.c. It should be + * simply moved to some header file instead. + */ +static int sync_page(struct page *page) +{ + struct address_space *mapping = page->mapping; + + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + if (mapping && mapping->a_ops && mapping->a_ops->sync_page) + return mapping->a_ops->sync_page(page); + return 0; +} + +static int ecryptfs_sync_page(struct page *page) +{ + int rc = 0; + struct inode *inode; + struct inode *lower_inode; + struct page *lower_page; + + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + inode = page->mapping->host; + lower_inode = ECRYPTFS_INODE_TO_LOWER(inode); + lower_page = grab_cache_page(lower_inode->i_mapping, page->index); + if (!lower_page) { + rc = -ENOMEM; + ecryptfs_printk(0, KERN_ERR, "Error from grab_cache_page " + "(no mem?)\n"); + goto out; + } + rc = sync_page(lower_page); + ecryptfs_printk(1, KERN_NOTICE, "Unlocking page with index = [%lu]\n", + lower_page->index); + unlock_page(lower_page); + page_cache_release(lower_page); +out: + return rc; +} + +struct address_space_operations ecryptfs_aops = { + .writepage = ecryptfs_writepage, + .readpage = ecryptfs_readpage, + .prepare_write = ecryptfs_prepare_write, + .commit_write = ecryptfs_commit_write, + .bmap = ecryptfs_bmap, + .sync_page = ecryptfs_sync_page, +}; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/