![Nick Piggin](/assets/img/avatar_default.png)
Ensure pages are uptodate after returning from read_cache_page, which allows us to cut out most of the filesystem-internal PageUptodate calls. I didn't have a great look down the call chains, but this appears to fixes 7 possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in block2mtd. All depending on whether the filler is async and/or can return with a !uptodate page. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
822 lines
24 KiB
C
822 lines
24 KiB
C
/**
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* eCryptfs: Linux filesystem encryption layer
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* This is where eCryptfs coordinates the symmetric encryption and
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* decryption of the file data as it passes between the lower
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* encrypted file and the upper decrypted file.
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*
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* Copyright (C) 1997-2003 Erez Zadok
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* Copyright (C) 2001-2003 Stony Brook University
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* Copyright (C) 2004-2007 International Business Machines Corp.
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* Author(s): Michael A. Halcrow <mahalcro@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/pagemap.h>
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#include <linux/writeback.h>
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#include <linux/page-flags.h>
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#include <linux/mount.h>
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#include <linux/file.h>
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#include <linux/crypto.h>
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#include <linux/scatterlist.h>
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#include "ecryptfs_kernel.h"
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struct kmem_cache *ecryptfs_lower_page_cache;
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/**
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* ecryptfs_get1page
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*
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* Get one page from cache or lower f/s, return error otherwise.
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*
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* Returns unlocked and up-to-date page (if ok), with increased
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* refcnt.
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*/
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static struct page *ecryptfs_get1page(struct file *file, int index)
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{
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struct dentry *dentry;
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struct inode *inode;
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struct address_space *mapping;
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dentry = file->f_path.dentry;
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inode = dentry->d_inode;
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mapping = inode->i_mapping;
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return read_mapping_page(mapping, index, (void *)file);
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}
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static
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int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros);
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/**
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* ecryptfs_fill_zeros
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* @file: The ecryptfs file
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* @new_length: The new length of the data in the underlying file;
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* everything between the prior end of the file and the
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* new end of the file will be filled with zero's.
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* new_length must be greater than current length
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*
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* Function for handling lseek-ing past the end of the file.
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*
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* This function does not support shrinking, only growing a file.
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*
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* Returns zero on success; non-zero otherwise.
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*/
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int ecryptfs_fill_zeros(struct file *file, loff_t new_length)
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{
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int rc = 0;
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struct dentry *dentry = file->f_path.dentry;
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struct inode *inode = dentry->d_inode;
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pgoff_t old_end_page_index = 0;
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pgoff_t index = old_end_page_index;
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int old_end_pos_in_page = -1;
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pgoff_t new_end_page_index;
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int new_end_pos_in_page;
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loff_t cur_length = i_size_read(inode);
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if (cur_length != 0) {
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index = old_end_page_index =
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((cur_length - 1) >> PAGE_CACHE_SHIFT);
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old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK);
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}
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new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
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new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
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ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; "
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"old_end_pos_in_page = [%d]; "
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"new_end_page_index = [0x%.16x]; "
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"new_end_pos_in_page = [%d]\n",
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old_end_page_index, old_end_pos_in_page,
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new_end_page_index, new_end_pos_in_page);
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if (old_end_page_index == new_end_page_index) {
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/* Start and end are in the same page; we just need to
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* set a portion of the existing page to zero's */
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rc = write_zeros(file, index, (old_end_pos_in_page + 1),
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(new_end_pos_in_page - old_end_pos_in_page));
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if (rc)
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ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
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"index=[0x%.16x], "
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"old_end_pos_in_page=[d], "
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"(PAGE_CACHE_SIZE - new_end_pos_in_page"
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"=[%d]"
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")=[d]) returned [%d]\n", file, index,
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old_end_pos_in_page,
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new_end_pos_in_page,
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(PAGE_CACHE_SIZE - new_end_pos_in_page),
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rc);
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goto out;
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}
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/* Fill the remainder of the previous last page with zeros */
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rc = write_zeros(file, index, (old_end_pos_in_page + 1),
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((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page));
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if (rc) {
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ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
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"index=[0x%.16x], old_end_pos_in_page=[d], "
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"(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
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"returned [%d]\n", file, index,
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old_end_pos_in_page,
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(PAGE_CACHE_SIZE - old_end_pos_in_page), rc);
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goto out;
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}
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index++;
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while (index < new_end_page_index) {
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/* Fill all intermediate pages with zeros */
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rc = write_zeros(file, index, 0, PAGE_CACHE_SIZE);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
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"index=[0x%.16x], "
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"old_end_pos_in_page=[d], "
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"(PAGE_CACHE_SIZE - new_end_pos_in_page"
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"=[%d]"
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")=[d]) returned [%d]\n", file, index,
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old_end_pos_in_page,
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new_end_pos_in_page,
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(PAGE_CACHE_SIZE - new_end_pos_in_page),
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rc);
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goto out;
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}
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index++;
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}
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/* Fill the portion at the beginning of the last new page with
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* zero's */
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rc = write_zeros(file, index, 0, (new_end_pos_in_page + 1));
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if (rc) {
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ecryptfs_printk(KERN_ERR, "write_zeros(file="
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"[%p], index=[0x%.16x], 0, "
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"new_end_pos_in_page=[%d]"
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"returned [%d]\n", file, index,
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new_end_pos_in_page, rc);
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goto out;
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}
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out:
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return rc;
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}
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/**
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* ecryptfs_writepage
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* @page: Page that is locked before this call is made
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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_writepage(struct page *page, struct writeback_control *wbc)
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{
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struct ecryptfs_page_crypt_context ctx;
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int rc;
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ctx.page = page;
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ctx.mode = ECRYPTFS_WRITEPAGE_MODE;
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ctx.param.wbc = wbc;
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rc = ecryptfs_encrypt_page(&ctx);
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if (rc) {
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ecryptfs_printk(KERN_WARNING, "Error encrypting "
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"page (upper index [0x%.16x])\n", page->index);
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ClearPageUptodate(page);
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goto out;
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}
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SetPageUptodate(page);
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unlock_page(page);
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out:
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return rc;
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}
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/**
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* Reads the data from the lower file file at index lower_page_index
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* and copies that data into page.
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*
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* @param page Page to fill
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* @param lower_page_index Index of the page in the lower file to get
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*/
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int ecryptfs_do_readpage(struct file *file, struct page *page,
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pgoff_t lower_page_index)
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{
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int rc;
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struct dentry *dentry;
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struct file *lower_file;
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struct dentry *lower_dentry;
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struct inode *inode;
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struct inode *lower_inode;
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char *page_data;
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struct page *lower_page = NULL;
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char *lower_page_data;
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const struct address_space_operations *lower_a_ops;
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dentry = file->f_path.dentry;
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lower_file = ecryptfs_file_to_lower(file);
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lower_dentry = ecryptfs_dentry_to_lower(dentry);
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inode = dentry->d_inode;
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lower_inode = ecryptfs_inode_to_lower(inode);
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lower_a_ops = lower_inode->i_mapping->a_ops;
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lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
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(filler_t *)lower_a_ops->readpage,
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(void *)lower_file);
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if (IS_ERR(lower_page)) {
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rc = PTR_ERR(lower_page);
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lower_page = NULL;
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ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
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goto out;
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}
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page_data = kmap_atomic(page, KM_USER0);
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lower_page_data = kmap_atomic(lower_page, KM_USER1);
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memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
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kunmap_atomic(lower_page_data, KM_USER1);
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kunmap_atomic(page_data, KM_USER0);
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flush_dcache_page(page);
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rc = 0;
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out:
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if (likely(lower_page))
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page_cache_release(lower_page);
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if (rc == 0)
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SetPageUptodate(page);
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else
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ClearPageUptodate(page);
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return rc;
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}
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/**
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* Header Extent:
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* Octets 0-7: Unencrypted file size (big-endian)
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* Octets 8-15: eCryptfs special marker
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* Octets 16-19: Flags
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* Octet 16: File format version number (between 0 and 255)
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* Octets 17-18: Reserved
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* Octet 19: Bit 1 (lsb): Reserved
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* Bit 2: Encrypted?
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* Bits 3-8: Reserved
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* Octets 20-23: Header extent size (big-endian)
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* Octets 24-25: Number of header extents at front of file
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* (big-endian)
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* Octet 26: Begin RFC 2440 authentication token packet set
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*/
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static void set_header_info(char *page_virt,
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struct ecryptfs_crypt_stat *crypt_stat)
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{
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size_t written;
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int save_num_header_extents_at_front =
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crypt_stat->num_header_extents_at_front;
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crypt_stat->num_header_extents_at_front = 1;
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ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
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crypt_stat->num_header_extents_at_front =
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save_num_header_extents_at_front;
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}
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/**
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* ecryptfs_readpage
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* @file: This is an ecryptfs file
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* @page: ecryptfs associated page to stick the read data into
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*
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* Read in a page, decrypting if necessary.
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*
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* Returns zero on success; non-zero on error.
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*/
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static int ecryptfs_readpage(struct file *file, struct page *page)
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{
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int rc = 0;
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struct ecryptfs_crypt_stat *crypt_stat;
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BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode));
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crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
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->crypt_stat;
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if (!crypt_stat
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|| !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
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|| (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
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ecryptfs_printk(KERN_DEBUG,
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"Passing through unencrypted page\n");
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rc = ecryptfs_do_readpage(file, page, page->index);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error reading page; rc = "
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"[%d]\n", rc);
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goto out;
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}
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} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
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if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
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int num_pages_in_header_region =
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(crypt_stat->header_extent_size
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/ PAGE_CACHE_SIZE);
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if (page->index < num_pages_in_header_region) {
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char *page_virt;
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page_virt = kmap_atomic(page, KM_USER0);
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memset(page_virt, 0, PAGE_CACHE_SIZE);
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if (page->index == 0) {
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rc = ecryptfs_read_xattr_region(
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page_virt, file->f_path.dentry);
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set_header_info(page_virt, crypt_stat);
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}
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kunmap_atomic(page_virt, KM_USER0);
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flush_dcache_page(page);
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if (rc) {
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printk(KERN_ERR "Error reading xattr "
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"region\n");
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goto out;
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}
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} else {
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rc = ecryptfs_do_readpage(
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file, page,
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(page->index
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- num_pages_in_header_region));
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if (rc) {
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printk(KERN_ERR "Error reading page; "
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"rc = [%d]\n", rc);
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goto out;
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}
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}
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} else {
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rc = ecryptfs_do_readpage(file, page, page->index);
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if (rc) {
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printk(KERN_ERR "Error reading page; rc = "
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"[%d]\n", rc);
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goto out;
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}
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}
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} else {
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rc = ecryptfs_decrypt_page(file, page);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error decrypting page; "
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"rc = [%d]\n", rc);
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goto out;
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}
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}
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SetPageUptodate(page);
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out:
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if (rc)
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ClearPageUptodate(page);
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ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
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page->index);
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unlock_page(page);
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return rc;
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}
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|
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/**
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* Called with lower inode mutex held.
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*/
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static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
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{
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struct inode *inode = page->mapping->host;
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int end_byte_in_page;
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char *page_virt;
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if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
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goto out;
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end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
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if (to > end_byte_in_page)
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end_byte_in_page = to;
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page_virt = kmap_atomic(page, KM_USER0);
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memset((page_virt + end_byte_in_page), 0,
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(PAGE_CACHE_SIZE - end_byte_in_page));
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kunmap_atomic(page_virt, KM_USER0);
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flush_dcache_page(page);
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out:
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return 0;
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}
|
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|
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static int ecryptfs_prepare_write(struct file *file, struct page *page,
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unsigned from, unsigned to)
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{
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int rc = 0;
|
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|
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if (from == 0 && to == PAGE_CACHE_SIZE)
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goto out; /* If we are writing a full page, it will be
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up to date. */
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if (!PageUptodate(page))
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rc = ecryptfs_do_readpage(file, page, page->index);
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out:
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return rc;
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}
|
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|
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int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
|
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struct inode *lower_inode,
|
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struct writeback_control *wbc)
|
|
{
|
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int rc = 0;
|
|
|
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rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
|
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if (rc) {
|
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ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
|
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"rc = [%d]\n", rc);
|
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goto out;
|
|
}
|
|
lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
|
|
page_cache_release(lower_page);
|
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out:
|
|
return rc;
|
|
}
|
|
|
|
static
|
|
void ecryptfs_release_lower_page(struct page *lower_page, int page_locked)
|
|
{
|
|
if (page_locked)
|
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unlock_page(lower_page);
|
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page_cache_release(lower_page);
|
|
}
|
|
|
|
/**
|
|
* ecryptfs_write_inode_size_to_header
|
|
*
|
|
* Writes the lower file size to the first 8 bytes of the header.
|
|
*
|
|
* Returns zero on success; non-zero on error.
|
|
*/
|
|
static 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;
|
|
const struct address_space_operations *lower_a_ops;
|
|
u64 file_size;
|
|
|
|
retry:
|
|
header_page = grab_cache_page(lower_inode->i_mapping, 0);
|
|
if (!header_page) {
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|
ecryptfs_printk(KERN_ERR, "grab_cache_page for "
|
|
"lower_page_index 0 failed\n");
|
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rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
lower_a_ops = lower_inode->i_mapping->a_ops;
|
|
rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
|
|
if (rc) {
|
|
if (rc == AOP_TRUNCATED_PAGE) {
|
|
ecryptfs_release_lower_page(header_page, 0);
|
|
goto retry;
|
|
} else
|
|
ecryptfs_release_lower_page(header_page, 1);
|
|
goto out;
|
|
}
|
|
file_size = (u64)i_size_read(inode);
|
|
ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
|
|
file_size = cpu_to_be64(file_size);
|
|
header_virt = kmap_atomic(header_page, KM_USER0);
|
|
memcpy(header_virt, &file_size, sizeof(u64));
|
|
kunmap_atomic(header_virt, KM_USER0);
|
|
flush_dcache_page(header_page);
|
|
rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
|
|
if (rc < 0)
|
|
ecryptfs_printk(KERN_ERR, "Error commiting header page "
|
|
"write\n");
|
|
if (rc == AOP_TRUNCATED_PAGE) {
|
|
ecryptfs_release_lower_page(header_page, 0);
|
|
goto retry;
|
|
} else
|
|
ecryptfs_release_lower_page(header_page, 1);
|
|
lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
|
|
mark_inode_dirty_sync(inode);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode,
|
|
struct inode *inode,
|
|
struct dentry *ecryptfs_dentry,
|
|
int lower_i_mutex_held)
|
|
{
|
|
ssize_t size;
|
|
void *xattr_virt;
|
|
struct dentry *lower_dentry;
|
|
u64 file_size;
|
|
int rc;
|
|
|
|
xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
|
|
if (!xattr_virt) {
|
|
printk(KERN_ERR "Out of memory whilst attempting to write "
|
|
"inode size to xattr\n");
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
|
|
if (!lower_dentry->d_inode->i_op->getxattr ||
|
|
!lower_dentry->d_inode->i_op->setxattr) {
|
|
printk(KERN_WARNING
|
|
"No support for setting xattr in lower filesystem\n");
|
|
rc = -ENOSYS;
|
|
kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
|
|
goto out;
|
|
}
|
|
if (!lower_i_mutex_held)
|
|
mutex_lock(&lower_dentry->d_inode->i_mutex);
|
|
size = lower_dentry->d_inode->i_op->getxattr(lower_dentry,
|
|
ECRYPTFS_XATTR_NAME,
|
|
xattr_virt,
|
|
PAGE_CACHE_SIZE);
|
|
if (!lower_i_mutex_held)
|
|
mutex_unlock(&lower_dentry->d_inode->i_mutex);
|
|
if (size < 0)
|
|
size = 8;
|
|
file_size = (u64)i_size_read(inode);
|
|
file_size = cpu_to_be64(file_size);
|
|
memcpy(xattr_virt, &file_size, sizeof(u64));
|
|
if (!lower_i_mutex_held)
|
|
mutex_lock(&lower_dentry->d_inode->i_mutex);
|
|
rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry,
|
|
ECRYPTFS_XATTR_NAME,
|
|
xattr_virt, size, 0);
|
|
if (!lower_i_mutex_held)
|
|
mutex_unlock(&lower_dentry->d_inode->i_mutex);
|
|
if (rc)
|
|
printk(KERN_ERR "Error whilst attempting to write inode size "
|
|
"to lower file xattr; rc = [%d]\n", rc);
|
|
kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
int
|
|
ecryptfs_write_inode_size_to_metadata(struct file *lower_file,
|
|
struct inode *lower_inode,
|
|
struct inode *inode,
|
|
struct dentry *ecryptfs_dentry,
|
|
int lower_i_mutex_held)
|
|
{
|
|
struct ecryptfs_crypt_stat *crypt_stat;
|
|
|
|
crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
|
|
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
|
|
return ecryptfs_write_inode_size_to_xattr(lower_inode, inode,
|
|
ecryptfs_dentry,
|
|
lower_i_mutex_held);
|
|
else
|
|
return ecryptfs_write_inode_size_to_header(lower_file,
|
|
lower_inode,
|
|
inode);
|
|
}
|
|
|
|
int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
|
|
struct file *lower_file,
|
|
unsigned long lower_page_index, int byte_offset,
|
|
int region_bytes)
|
|
{
|
|
int rc = 0;
|
|
|
|
retry:
|
|
*lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index);
|
|
if (!(*lower_page)) {
|
|
rc = -EINVAL;
|
|
ecryptfs_printk(KERN_ERR, "Error attempting to grab "
|
|
"lower page with index [0x%.16x]\n",
|
|
lower_page_index);
|
|
goto out;
|
|
}
|
|
rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
|
|
(*lower_page),
|
|
byte_offset,
|
|
region_bytes);
|
|
if (rc) {
|
|
if (rc == AOP_TRUNCATED_PAGE) {
|
|
ecryptfs_release_lower_page(*lower_page, 0);
|
|
goto retry;
|
|
} else {
|
|
ecryptfs_printk(KERN_ERR, "prepare_write for "
|
|
"lower_page_index = [0x%.16x] failed; rc = "
|
|
"[%d]\n", lower_page_index, rc);
|
|
ecryptfs_release_lower_page(*lower_page, 1);
|
|
(*lower_page) = NULL;
|
|
}
|
|
}
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* ecryptfs_commit_lower_page
|
|
*
|
|
* Returns zero on success; non-zero on error
|
|
*/
|
|
int
|
|
ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
|
|
struct file *lower_file, int byte_offset,
|
|
int region_size)
|
|
{
|
|
int page_locked = 1;
|
|
int rc = 0;
|
|
|
|
rc = lower_inode->i_mapping->a_ops->commit_write(
|
|
lower_file, lower_page, byte_offset, region_size);
|
|
if (rc == AOP_TRUNCATED_PAGE)
|
|
page_locked = 0;
|
|
if (rc < 0) {
|
|
ecryptfs_printk(KERN_ERR,
|
|
"Error committing write; rc = [%d]\n", rc);
|
|
} else
|
|
rc = 0;
|
|
ecryptfs_release_lower_page(lower_page, page_locked);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* ecryptfs_copy_page_to_lower
|
|
*
|
|
* Used for plaintext pass-through; no page index interpolation
|
|
* required.
|
|
*/
|
|
int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
|
|
struct file *lower_file)
|
|
{
|
|
int rc = 0;
|
|
struct page *lower_page;
|
|
|
|
rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
|
|
page->index, 0, PAGE_CACHE_SIZE);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error attempting to get page "
|
|
"at index [0x%.16x]\n", page->index);
|
|
goto out;
|
|
}
|
|
/* TODO: aops */
|
|
memcpy((char *)page_address(lower_page), page_address(page),
|
|
PAGE_CACHE_SIZE);
|
|
rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
|
|
0, PAGE_CACHE_SIZE);
|
|
if (rc)
|
|
ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
|
|
"at index [0x%.16x]\n", page->index);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
struct kmem_cache *ecryptfs_xattr_cache;
|
|
|
|
/**
|
|
* ecryptfs_commit_write
|
|
* @file: The eCryptfs file object
|
|
* @page: The eCryptfs page
|
|
* @from: Ignored (we rotate the page IV on each write)
|
|
* @to: Ignored
|
|
*
|
|
* 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.
|
|
*/
|
|
static int ecryptfs_commit_write(struct file *file, struct page *page,
|
|
unsigned from, unsigned to)
|
|
{
|
|
struct ecryptfs_page_crypt_context ctx;
|
|
loff_t pos;
|
|
struct inode *inode;
|
|
struct inode *lower_inode;
|
|
struct file *lower_file;
|
|
struct ecryptfs_crypt_stat *crypt_stat;
|
|
int rc;
|
|
|
|
inode = page->mapping->host;
|
|
lower_inode = ecryptfs_inode_to_lower(inode);
|
|
lower_file = ecryptfs_file_to_lower(file);
|
|
mutex_lock(&lower_inode->i_mutex);
|
|
crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
|
|
->crypt_stat;
|
|
if (crypt_stat->flags & ECRYPTFS_NEW_FILE) {
|
|
ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
|
|
"crypt_stat at memory location [%p]\n", crypt_stat);
|
|
crypt_stat->flags &= ~(ECRYPTFS_NEW_FILE);
|
|
} else
|
|
ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
|
|
ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
|
|
"(page w/ index = [0x%.16x], to = [%d])\n", page->index,
|
|
to);
|
|
rc = fill_zeros_to_end_of_page(page, to);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
|
|
"zeros in page with index = [0x%.16x]\n",
|
|
page->index);
|
|
goto out;
|
|
}
|
|
ctx.page = page;
|
|
ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE;
|
|
ctx.param.lower_file = lower_file;
|
|
rc = ecryptfs_encrypt_page(&ctx);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
|
|
"index [0x%.16x])\n", page->index);
|
|
goto out;
|
|
}
|
|
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(KERN_DEBUG, "Expanded file size to "
|
|
"[0x%.16x]\n", i_size_read(inode));
|
|
}
|
|
rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
|
|
inode, file->f_dentry,
|
|
ECRYPTFS_LOWER_I_MUTEX_HELD);
|
|
if (rc)
|
|
printk(KERN_ERR "Error writing inode size to metadata; "
|
|
"rc = [%d]\n", rc);
|
|
lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
|
|
mark_inode_dirty_sync(inode);
|
|
out:
|
|
if (rc < 0)
|
|
ClearPageUptodate(page);
|
|
else
|
|
SetPageUptodate(page);
|
|
mutex_unlock(&lower_inode->i_mutex);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* write_zeros
|
|
* @file: The ecryptfs file
|
|
* @index: The index in which we are writing
|
|
* @start: The position after the last block of data
|
|
* @num_zeros: The number of zeros to write
|
|
*
|
|
* Write a specified number of zero's to a page.
|
|
*
|
|
* (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
|
|
*/
|
|
static
|
|
int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
|
|
{
|
|
int rc = 0;
|
|
struct page *tmp_page;
|
|
char *tmp_page_virt;
|
|
|
|
tmp_page = ecryptfs_get1page(file, index);
|
|
if (IS_ERR(tmp_page)) {
|
|
ecryptfs_printk(KERN_ERR, "Error getting page at index "
|
|
"[0x%.16x]\n", index);
|
|
rc = PTR_ERR(tmp_page);
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
|
|
"to remainder of page at index [0x%.16x]\n",
|
|
index);
|
|
page_cache_release(tmp_page);
|
|
goto out;
|
|
}
|
|
tmp_page_virt = kmap_atomic(tmp_page, KM_USER0);
|
|
memset(((char *)tmp_page_virt + start), 0, num_zeros);
|
|
kunmap_atomic(tmp_page_virt, KM_USER0);
|
|
flush_dcache_page(tmp_page);
|
|
rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
|
|
if (rc < 0) {
|
|
ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
|
|
"to remainder of page at index [0x%.16x]\n",
|
|
index);
|
|
page_cache_release(tmp_page);
|
|
goto out;
|
|
}
|
|
rc = 0;
|
|
page_cache_release(tmp_page);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
|
|
{
|
|
int rc = 0;
|
|
struct inode *inode;
|
|
struct inode *lower_inode;
|
|
|
|
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;
|
|
}
|
|
|
|
static void ecryptfs_sync_page(struct page *page)
|
|
{
|
|
struct inode *inode;
|
|
struct inode *lower_inode;
|
|
struct page *lower_page;
|
|
|
|
inode = page->mapping->host;
|
|
lower_inode = ecryptfs_inode_to_lower(inode);
|
|
/* NOTE: Recently swapped with grab_cache_page(), since
|
|
* sync_page() just makes sure that pending I/O gets done. */
|
|
lower_page = find_lock_page(lower_inode->i_mapping, page->index);
|
|
if (!lower_page) {
|
|
ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n");
|
|
return;
|
|
}
|
|
lower_page->mapping->a_ops->sync_page(lower_page);
|
|
ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
|
|
lower_page->index);
|
|
unlock_page(lower_page);
|
|
page_cache_release(lower_page);
|
|
}
|
|
|
|
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,
|
|
};
|