| /** |
| * eCryptfs: Linux filesystem encryption layer |
| * This is where eCryptfs coordinates the symmetric encryption and |
| * decryption of the file data as it passes between the lower |
| * encrypted file and the upper decrypted file. |
| * |
| * Copyright (C) 1997-2003 Erez Zadok |
| * Copyright (C) 2001-2003 Stony Brook University |
| * Copyright (C) 2004-2007 International Business Machines Corp. |
| * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License as |
| * published by the Free Software Foundation; either version 2 of the |
| * License, or (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA |
| * 02111-1307, USA. |
| */ |
| |
| #include <linux/pagemap.h> |
| #include <linux/writeback.h> |
| #include <linux/page-flags.h> |
| #include <linux/mount.h> |
| #include <linux/file.h> |
| #include <linux/crypto.h> |
| #include <linux/scatterlist.h> |
| #include "ecryptfs_kernel.h" |
| |
| struct kmem_cache *ecryptfs_lower_page_cache; |
| |
| /** |
| * ecryptfs_get1page |
| * |
| * Get one page from cache or lower f/s, return error otherwise. |
| * |
| * Returns 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; |
| |
| dentry = file->f_path.dentry; |
| inode = dentry->d_inode; |
| mapping = inode->i_mapping; |
| 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); |
| out: |
| return page; |
| } |
| |
| static |
| int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros); |
| |
| /** |
| * ecryptfs_fill_zeros |
| * @file: The ecryptfs file |
| * @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. |
| * new_length must be greater than current length |
| * |
| * Function for handling lseek-ing past the end of the file. |
| * |
| * This function does not support shrinking, only growing a file. |
| * |
| * Returns 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_path.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); |
| |
| 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(KERN_DEBUG, "old_end_page_index = [0x%.16x]; " |
| "old_end_pos_in_page = [%d]; " |
| "new_end_page_index = [0x%.16x]; " |
| "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(KERN_ERR, "write_zeros(file=[%p], " |
| "index=[0x%.16x], " |
| "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; |
| } |
| /* 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(KERN_ERR, "write_zeros(file=[%p], " |
| "index=[0x%.16x], 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(KERN_ERR, "write_zeros(file=[%p], " |
| "index=[0x%.16x], " |
| "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(KERN_ERR, "write_zeros(file=" |
| "[%p], index=[0x%.16x], 0, " |
| "new_end_pos_in_page=[%d]" |
| "returned [%d]\n", file, index, |
| new_end_pos_in_page, rc); |
| goto out; |
| } |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_writepage |
| * @page: Page that is locked before this call is made |
| * |
| * Returns zero on success; non-zero otherwise |
| */ |
| static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc) |
| { |
| struct ecryptfs_page_crypt_context ctx; |
| int rc; |
| |
| ctx.page = page; |
| ctx.mode = ECRYPTFS_WRITEPAGE_MODE; |
| ctx.param.wbc = wbc; |
| rc = ecryptfs_encrypt_page(&ctx); |
| if (rc) { |
| ecryptfs_printk(KERN_WARNING, "Error encrypting " |
| "page (upper index [0x%.16x])\n", page->index); |
| ClearPageUptodate(page); |
| goto out; |
| } |
| SetPageUptodate(page); |
| unlock_page(page); |
| out: |
| 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 |
| */ |
| int ecryptfs_do_readpage(struct file *file, struct page *page, |
| pgoff_t lower_page_index) |
| { |
| int rc; |
| 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; |
| const struct address_space_operations *lower_a_ops; |
| |
| dentry = file->f_path.dentry; |
| 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(KERN_ERR, "Error reading from page cache\n"); |
| goto out; |
| } |
| wait_on_page_locked(lower_page); |
| page_data = kmap_atomic(page, KM_USER0); |
| lower_page_data = kmap_atomic(lower_page, KM_USER1); |
| memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE); |
| kunmap_atomic(lower_page_data, KM_USER1); |
| kunmap_atomic(page_data, KM_USER0); |
| rc = 0; |
| out: |
| if (likely(lower_page)) |
| page_cache_release(lower_page); |
| if (rc == 0) |
| SetPageUptodate(page); |
| else |
| ClearPageUptodate(page); |
| return rc; |
| } |
| /** |
| * Header Extent: |
| * Octets 0-7: Unencrypted file size (big-endian) |
| * Octets 8-15: eCryptfs special marker |
| * Octets 16-19: Flags |
| * Octet 16: File format version number (between 0 and 255) |
| * Octets 17-18: Reserved |
| * Octet 19: Bit 1 (lsb): Reserved |
| * Bit 2: Encrypted? |
| * Bits 3-8: Reserved |
| * Octets 20-23: Header extent size (big-endian) |
| * Octets 24-25: Number of header extents at front of file |
| * (big-endian) |
| * Octet 26: Begin RFC 2440 authentication token packet set |
| */ |
| static void set_header_info(char *page_virt, |
| struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| size_t written; |
| int save_num_header_extents_at_front = |
| crypt_stat->num_header_extents_at_front; |
| |
| crypt_stat->num_header_extents_at_front = 1; |
| ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written); |
| crypt_stat->num_header_extents_at_front = |
| save_num_header_extents_at_front; |
| } |
| |
| /** |
| * ecryptfs_readpage |
| * @file: This is an ecryptfs file |
| * @page: ecryptfs associated page to stick the read data into |
| * |
| * Read in a page, decrypting if necessary. |
| * |
| * Returns zero on success; non-zero on error. |
| */ |
| static int ecryptfs_readpage(struct file *file, struct page *page) |
| { |
| int rc = 0; |
| struct ecryptfs_crypt_stat *crypt_stat; |
| |
| BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode)); |
| crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode) |
| ->crypt_stat; |
| if (!crypt_stat |
| || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED) |
| || ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) { |
| ecryptfs_printk(KERN_DEBUG, |
| "Passing through unencrypted page\n"); |
| rc = ecryptfs_do_readpage(file, page, page->index); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error reading page; rc = " |
| "[%d]\n", rc); |
| goto out; |
| } |
| } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) { |
| if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) { |
| int num_pages_in_header_region = |
| (crypt_stat->header_extent_size |
| / PAGE_CACHE_SIZE); |
| |
| if (page->index < num_pages_in_header_region) { |
| char *page_virt; |
| |
| page_virt = kmap_atomic(page, KM_USER0); |
| memset(page_virt, 0, PAGE_CACHE_SIZE); |
| if (page->index == 0) { |
| rc = ecryptfs_read_xattr_region( |
| page_virt, file->f_path.dentry); |
| set_header_info(page_virt, crypt_stat); |
| } |
| kunmap_atomic(page_virt, KM_USER0); |
| if (rc) { |
| printk(KERN_ERR "Error reading xattr " |
| "region\n"); |
| goto out; |
| } |
| } else { |
| rc = ecryptfs_do_readpage( |
| file, page, |
| (page->index |
| - num_pages_in_header_region)); |
| if (rc) { |
| printk(KERN_ERR "Error reading page; " |
| "rc = [%d]\n", rc); |
| goto out; |
| } |
| } |
| } else { |
| rc = ecryptfs_do_readpage(file, page, page->index); |
| if (rc) { |
| printk(KERN_ERR "Error reading page; rc = " |
| "[%d]\n", rc); |
| goto out; |
| } |
| } |
| } else { |
| rc = ecryptfs_decrypt_page(file, page); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error decrypting page; " |
| "rc = [%d]\n", rc); |
| goto out; |
| } |
| } |
| SetPageUptodate(page); |
| out: |
| if (rc) |
| ClearPageUptodate(page); |
| ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", |
| page->index); |
| unlock_page(page); |
| return rc; |
| } |
| |
| /** |
| * Called with lower inode mutex held. |
| */ |
| static int fill_zeros_to_end_of_page(struct page *page, unsigned int 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) |
| goto out; |
| 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_atomic(page, KM_USER0); |
| memset((page_virt + end_byte_in_page), 0, |
| (PAGE_CACHE_SIZE - end_byte_in_page)); |
| kunmap_atomic(page_virt, KM_USER0); |
| out: |
| return 0; |
| } |
| |
| static int ecryptfs_prepare_write(struct file *file, struct page *page, |
| unsigned from, unsigned to) |
| { |
| int rc = 0; |
| |
| 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)) |
| rc = ecryptfs_do_readpage(file, page, page->index); |
| out: |
| return rc; |
| } |
| |
| int ecryptfs_writepage_and_release_lower_page(struct page *lower_page, |
| struct inode *lower_inode, |
| struct writeback_control *wbc) |
| { |
| int rc = 0; |
| |
| rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); " |
| "rc = [%d]\n", rc); |
| goto out; |
| } |
| lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; |
| page_cache_release(lower_page); |
| out: |
| return rc; |
| } |
| |
| static void ecryptfs_release_lower_page(struct page *lower_page) |
| { |
| unlock_page(lower_page); |
| 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; |
| |
| header_page = grab_cache_page(lower_inode->i_mapping, 0); |
| if (!header_page) { |
| ecryptfs_printk(KERN_ERR, "grab_cache_page for " |
| "lower_page_index 0 failed\n"); |
| 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); |
| 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); |
| 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"); |
| ecryptfs_release_lower_page(header_page); |
| 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) { |
| 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; |
| |
| *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) { |
| ecryptfs_printk(KERN_ERR, "prepare_write for " |
| "lower_page_index = [0x%.16x] failed; rc = " |
| "[%d]\n", lower_page_index, rc); |
| } |
| out: |
| if (rc && (*lower_page)) { |
| ecryptfs_release_lower_page(*lower_page); |
| (*lower_page) = NULL; |
| } |
| 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 rc = 0; |
| |
| rc = lower_inode->i_mapping->a_ops->commit_write( |
| lower_file, lower_page, byte_offset, region_size); |
| if (rc < 0) { |
| ecryptfs_printk(KERN_ERR, |
| "Error committing write; rc = [%d]\n", rc); |
| } else |
| rc = 0; |
| ecryptfs_release_lower_page(lower_page); |
| 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 (ECRYPTFS_CHECK_FLAG(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); |
| ECRYPTFS_CLEAR_FLAG(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); |
| 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, |
| }; |