err.no Git - linux-2.6/blob - fs/ecryptfs/mmap.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  * This is where eCryptfs coordinates the symmetric encryption and
   4  * decryption of the file data as it passes between the lower
   5  * encrypted file and the upper decrypted file.
   6  *
   7  * Copyright (C) 1997-2003 Erez Zadok
   8  * Copyright (C) 2001-2003 Stony Brook University
   9  * Copyright (C) 2004-2007 International Business Machines Corp.
  10  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  25  * 02111-1307, USA.
  26  */
  27
  28 #include <linux/pagemap.h>
  29 #include <linux/writeback.h>
  30 #include <linux/page-flags.h>
  31 #include <linux/mount.h>
  32 #include <linux/file.h>
  33 #include <linux/crypto.h>
  34 #include <linux/scatterlist.h>
  35 #include "ecryptfs_kernel.h"
  36
  37 struct kmem_cache *ecryptfs_lower_page_cache;
  38
  39 /**
  40  * ecryptfs_get1page
  41  *
  42  * Get one page from cache or lower f/s, return error otherwise.
  43  *
  44  * Returns unlocked and up-to-date page (if ok), with increased
  45  * refcnt.
  46  */
  47 struct page *ecryptfs_get1page(struct file *file, loff_t index)
  48 {
  49         struct dentry *dentry;
  50         struct inode *inode;
  51         struct address_space *mapping;
  52
  53         dentry = file->f_path.dentry;
  54         inode = dentry->d_inode;
  55         mapping = inode->i_mapping;
  56         return read_mapping_page(mapping, index, (void *)file);
  57 }
  58
  59 /**
  60  * ecryptfs_fill_zeros
  61  * @file: The ecryptfs file
  62  * @new_length: The new length of the data in the underlying file;
  63  *              everything between the prior end of the file and the
  64  *              new end of the file will be filled with zero's.
  65  *              new_length must be greater than  current length
  66  *
  67  * Function for handling lseek-ing past the end of the file.
  68  *
  69  * This function does not support shrinking, only growing a file.
  70  *
  71  * Returns zero on success; non-zero otherwise.
  72  */
  73 int ecryptfs_fill_zeros(struct file *file, loff_t new_length)
  74 {
  75         int rc = 0;
  76         struct dentry *dentry = file->f_path.dentry;
  77         struct inode *inode = dentry->d_inode;
  78         pgoff_t old_end_page_index = 0;
  79         pgoff_t index = old_end_page_index;
  80         int old_end_pos_in_page = -1;
  81         pgoff_t new_end_page_index;
  82         int new_end_pos_in_page;
  83         loff_t cur_length = i_size_read(inode);
  84
  85         if (cur_length != 0) {
  86                 index = old_end_page_index =
  87                     ((cur_length - 1) >> PAGE_CACHE_SHIFT);
  88                 old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK);
  89         }
  90         new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
  91         new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
  92         ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; "
  93                         "old_end_pos_in_page = [%d]; "
  94                         "new_end_page_index = [0x%.16x]; "
  95                         "new_end_pos_in_page = [%d]\n",
  96                         old_end_page_index, old_end_pos_in_page,
  97                         new_end_page_index, new_end_pos_in_page);
  98         if (old_end_page_index == new_end_page_index) {
  99                 /* Start and end are in the same page; we just need to
 100                  * set a portion of the existing page to zero's */
 101                 rc = ecryptfs_write_zeros(file, index,
 102                                           (old_end_pos_in_page + 1),
 103                                           (new_end_pos_in_page
 104                                            - old_end_pos_in_page));
 105                 if (rc)
 106                         ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros("
 107                                         "file=[%p], "
 108                                         "index=[0x%.16x], "
 109                                         "old_end_pos_in_page=[d], "
 110                                         "(PAGE_CACHE_SIZE - new_end_pos_in_page"
 111                                         "=[%d]"
 112                                         ")=[d]) returned [%d]\n", file, index,
 113                                         old_end_pos_in_page,
 114                                         new_end_pos_in_page,
 115                                         (PAGE_CACHE_SIZE - new_end_pos_in_page),
 116                                         rc);
 117                 goto out;
 118         }
 119         /* Fill the remainder of the previous last page with zeros */
 120         rc = ecryptfs_write_zeros(file, index, (old_end_pos_in_page + 1),
 121                          ((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page));
 122         if (rc) {
 123                 ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros(file=[%p], "
 124                                 "index=[0x%.16x], old_end_pos_in_page=[d], "
 125                                 "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
 126                                 "returned [%d]\n", file, index,
 127                                 old_end_pos_in_page,
 128                                 (PAGE_CACHE_SIZE - old_end_pos_in_page), rc);
 129                 goto out;
 130         }
 131         index++;
 132         while (index < new_end_page_index) {
 133                 /* Fill all intermediate pages with zeros */
 134                 rc = ecryptfs_write_zeros(file, index, 0, PAGE_CACHE_SIZE);
 135                 if (rc) {
 136                         ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros("
 137                                         "file=[%p], "
 138                                         "index=[0x%.16x], "
 139                                         "old_end_pos_in_page=[d], "
 140                                         "(PAGE_CACHE_SIZE - new_end_pos_in_page"
 141                                         "=[%d]"
 142                                         ")=[d]) returned [%d]\n", file, index,
 143                                         old_end_pos_in_page,
 144                                         new_end_pos_in_page,
 145                                         (PAGE_CACHE_SIZE - new_end_pos_in_page),
 146                                         rc);
 147                         goto out;
 148                 }
 149                 index++;
 150         }
 151         /* Fill the portion at the beginning of the last new page with
 152          * zero's */
 153         rc = ecryptfs_write_zeros(file, index, 0, (new_end_pos_in_page + 1));
 154         if (rc) {
 155                 ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros(file="
 156                                 "[%p], index=[0x%.16x], 0, "
 157                                 "new_end_pos_in_page=[%d]"
 158                                 "returned [%d]\n", file, index,
 159                                 new_end_pos_in_page, rc);
 160                 goto out;
 161         }
 162 out:
 163         return rc;
 164 }
 165
 166 /**
 167  * ecryptfs_writepage
 168  * @page: Page that is locked before this call is made
 169  *
 170  * Returns zero on success; non-zero otherwise
 171  */
 172 static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
 173 {
 174         int rc;
 175
 176         rc = ecryptfs_encrypt_page(page);
 177         if (rc) {
 178                 ecryptfs_printk(KERN_WARNING, "Error encrypting "
 179                                 "page (upper index [0x%.16x])\n", page->index);
 180                 ClearPageUptodate(page);
 181                 goto out;
 182         }
 183         SetPageUptodate(page);
 184         unlock_page(page);
 185 out:
 186         return rc;
 187 }
 188
 189 /**
 190  * Reads the data from the lower file file at index lower_page_index
 191  * and copies that data into page.
 192  *
 193  * @param page  Page to fill
 194  * @param lower_page_index Index of the page in the lower file to get
 195  */
 196 int ecryptfs_do_readpage(struct file *file, struct page *page,
 197                          pgoff_t lower_page_index)
 198 {
 199         int rc;
 200         struct dentry *dentry;
 201         struct file *lower_file;
 202         struct dentry *lower_dentry;
 203         struct inode *inode;
 204         struct inode *lower_inode;
 205         char *page_data;
 206         struct page *lower_page = NULL;
 207         char *lower_page_data;
 208         const struct address_space_operations *lower_a_ops;
 209
 210         dentry = file->f_path.dentry;
 211         lower_file = ecryptfs_file_to_lower(file);
 212         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 213         inode = dentry->d_inode;
 214         lower_inode = ecryptfs_inode_to_lower(inode);
 215         lower_a_ops = lower_inode->i_mapping->a_ops;
 216         lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
 217                                      (filler_t *)lower_a_ops->readpage,
 218                                      (void *)lower_file);
 219         if (IS_ERR(lower_page)) {
 220                 rc = PTR_ERR(lower_page);
 221                 lower_page = NULL;
 222                 ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
 223                 goto out;
 224         }
 225         page_data = kmap_atomic(page, KM_USER0);
 226         lower_page_data = kmap_atomic(lower_page, KM_USER1);
 227         memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
 228         kunmap_atomic(lower_page_data, KM_USER1);
 229         kunmap_atomic(page_data, KM_USER0);
 230         flush_dcache_page(page);
 231         rc = 0;
 232 out:
 233         if (likely(lower_page))
 234                 page_cache_release(lower_page);
 235         if (rc == 0)
 236                 SetPageUptodate(page);
 237         else
 238                 ClearPageUptodate(page);
 239         return rc;
 240 }
 241 /**
 242  *   Header Extent:
 243  *     Octets 0-7:        Unencrypted file size (big-endian)
 244  *     Octets 8-15:       eCryptfs special marker
 245  *     Octets 16-19:      Flags
 246  *      Octet 16:         File format version number (between 0 and 255)
 247  *      Octets 17-18:     Reserved
 248  *      Octet 19:         Bit 1 (lsb): Reserved
 249  *                        Bit 2: Encrypted?
 250  *                        Bits 3-8: Reserved
 251  *     Octets 20-23:      Header extent size (big-endian)
 252  *     Octets 24-25:      Number of header extents at front of file
 253  *                        (big-endian)
 254  *     Octet  26:         Begin RFC 2440 authentication token packet set
 255  */
 256 static void set_header_info(char *page_virt,
 257                             struct ecryptfs_crypt_stat *crypt_stat)
 258 {
 259         size_t written;
 260         int save_num_header_extents_at_front =
 261                 crypt_stat->num_header_extents_at_front;
 262
 263         crypt_stat->num_header_extents_at_front = 1;
 264         ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
 265         crypt_stat->num_header_extents_at_front =
 266                 save_num_header_extents_at_front;
 267 }
 268
 269 /**
 270  * ecryptfs_readpage
 271  * @file: This is an ecryptfs file
 272  * @page: ecryptfs associated page to stick the read data into
 273  *
 274  * Read in a page, decrypting if necessary.
 275  *
 276  * Returns zero on success; non-zero on error.
 277  */
 278 static int ecryptfs_readpage(struct file *file, struct page *page)
 279 {
 280         int rc = 0;
 281         struct ecryptfs_crypt_stat *crypt_stat;
 282
 283         BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode));
 284         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
 285                         ->crypt_stat;
 286         if (!crypt_stat
 287             || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
 288             || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
 289                 ecryptfs_printk(KERN_DEBUG,
 290                                 "Passing through unencrypted page\n");
 291                 rc = ecryptfs_do_readpage(file, page, page->index);
 292                 if (rc) {
 293                         ecryptfs_printk(KERN_ERR, "Error reading page; rc = "
 294                                         "[%d]\n", rc);
 295                         goto out;
 296                 }
 297         } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
 298                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
 299                         int num_pages_in_header_region =
 300                                 (crypt_stat->extent_size
 301                                  / PAGE_CACHE_SIZE);
 302
 303                         if (page->index < num_pages_in_header_region) {
 304                                 char *page_virt;
 305
 306                                 page_virt = kmap_atomic(page, KM_USER0);
 307                                 memset(page_virt, 0, PAGE_CACHE_SIZE);
 308                                 if (page->index == 0) {
 309                                         rc = ecryptfs_read_xattr_region(
 310                                                 page_virt, page->mapping->host);
 311                                         set_header_info(page_virt, crypt_stat);
 312                                 }
 313                                 kunmap_atomic(page_virt, KM_USER0);
 314                                 flush_dcache_page(page);
 315                                 if (rc) {
 316                                         printk(KERN_ERR "Error reading xattr "
 317                                                "region\n");
 318                                         goto out;
 319                                 }
 320                         } else {
 321                                 rc = ecryptfs_do_readpage(
 322                                         file, page,
 323                                         (page->index
 324                                          - num_pages_in_header_region));
 325                                 if (rc) {
 326                                         printk(KERN_ERR "Error reading page; "
 327                                                "rc = [%d]\n", rc);
 328                                         goto out;
 329                                 }
 330                         }
 331                 } else {
 332                         rc = ecryptfs_do_readpage(file, page, page->index);
 333                         if (rc) {
 334                                 printk(KERN_ERR "Error reading page; rc = "
 335                                        "[%d]\n", rc);
 336                                 goto out;
 337                         }
 338                 }
 339         } else {
 340                 rc = ecryptfs_decrypt_page(page);
 341                 if (rc) {
 342                         ecryptfs_printk(KERN_ERR, "Error decrypting page; "
 343                                         "rc = [%d]\n", rc);
 344                         goto out;
 345                 }
 346         }
 347         SetPageUptodate(page);
 348 out:
 349         if (rc)
 350                 ClearPageUptodate(page);
 351         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
 352                         page->index);
 353         unlock_page(page);
 354         return rc;
 355 }
 356
 357 /**
 358  * Called with lower inode mutex held.
 359  */
 360 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
 361 {
 362         struct inode *inode = page->mapping->host;
 363         int end_byte_in_page;
 364
 365         if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
 366                 goto out;
 367         end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
 368         if (to > end_byte_in_page)
 369                 end_byte_in_page = to;
 370         zero_user_page(page, end_byte_in_page,
 371                 PAGE_CACHE_SIZE - end_byte_in_page, KM_USER0);
 372 out:
 373         return 0;
 374 }
 375
 376 /**
 377  * eCryptfs does not currently support holes. When writing after a
 378  * seek past the end of the file, eCryptfs fills in 0's through to the
 379  * current location. The code to fill in the 0's to all the
 380  * intermediate pages calls ecryptfs_prepare_write_no_truncate().
 381  */
 382 static int
 383 ecryptfs_prepare_write_no_truncate(struct file *file, struct page *page,
 384                                    unsigned from, unsigned to)
 385 {
 386         int rc = 0;
 387
 388         if (from == 0 && to == PAGE_CACHE_SIZE)
 389                 goto out;       /* If we are writing a full page, it will be
 390                                    up to date. */
 391         if (!PageUptodate(page))
 392                 rc = ecryptfs_do_readpage(file, page, page->index);
 393 out:
 394         return rc;
 395 }
 396
 397 static int ecryptfs_prepare_write(struct file *file, struct page *page,
 398                                   unsigned from, unsigned to)
 399 {
 400         int rc = 0;
 401
 402         if (from == 0 && to == PAGE_CACHE_SIZE)
 403                 goto out;       /* If we are writing a full page, it will be
 404                                    up to date. */
 405         if (!PageUptodate(page))
 406                 rc = ecryptfs_do_readpage(file, page, page->index);
 407         if (page->index != 0) {
 408                 loff_t end_of_prev_pg_pos = page_offset(page) - 1;
 409
 410                 if (end_of_prev_pg_pos > i_size_read(page->mapping->host)) {
 411                         rc = ecryptfs_truncate(file->f_path.dentry,
 412                                                end_of_prev_pg_pos);
 413                         if (rc) {
 414                                 printk(KERN_ERR "Error on attempt to "
 415                                        "truncate to (higher) offset [%lld];"
 416                                        " rc = [%d]\n", end_of_prev_pg_pos, rc);
 417                                 goto out;
 418                         }
 419                 }
 420                 if (end_of_prev_pg_pos + 1 > i_size_read(page->mapping->host))
 421                         zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0);
 422         }
 423 out:
 424         return rc;
 425 }
 426
 427 int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
 428                                               struct inode *lower_inode,
 429                                               struct writeback_control *wbc)
 430 {
 431         int rc = 0;
 432
 433         rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
 434         if (rc) {
 435                 ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
 436                                 "rc = [%d]\n", rc);
 437                 goto out;
 438         }
 439         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 440         page_cache_release(lower_page);
 441 out:
 442         return rc;
 443 }
 444
 445 static void ecryptfs_release_lower_page(struct page *lower_page)
 446 {
 447         unlock_page(lower_page);
 448         page_cache_release(lower_page);
 449 }
 450
 451 /**
 452  * ecryptfs_write_inode_size_to_header
 453  *
 454  * Writes the lower file size to the first 8 bytes of the header.
 455  *
 456  * Returns zero on success; non-zero on error.
 457  */
 458 static int ecryptfs_write_inode_size_to_header(struct inode *ecryptfs_inode)
 459 {
 460         u64 file_size;
 461         char *file_size_virt;
 462         int rc;
 463
 464         file_size_virt = kmalloc(sizeof(u64), GFP_KERNEL);
 465         if (!file_size_virt) {
 466                 rc = -ENOMEM;
 467                 goto out;
 468         }
 469         file_size = (u64)i_size_read(ecryptfs_inode);
 470         file_size = cpu_to_be64(file_size);
 471         memcpy(file_size_virt, &file_size, sizeof(u64));
 472         rc = ecryptfs_write_lower(ecryptfs_inode, file_size_virt, 0,
 473                                   sizeof(u64));
 474         kfree(file_size_virt);
 475         if (rc)
 476                 printk(KERN_ERR "%s: Error writing file size to header; "
 477                        "rc = [%d]\n", __FUNCTION__, rc);
 478 out:
 479         return rc;
 480 }
 481
 482 struct kmem_cache *ecryptfs_xattr_cache;
 483
 484 static int ecryptfs_write_inode_size_to_xattr(struct inode *ecryptfs_inode)
 485 {
 486         ssize_t size;
 487         void *xattr_virt;
 488         struct dentry *lower_dentry =
 489                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
 490         struct inode *lower_inode = lower_dentry->d_inode;
 491         u64 file_size;
 492         int rc;
 493
 494         if (!lower_inode->i_op->getxattr || !lower_inode->i_op->setxattr) {
 495                 printk(KERN_WARNING
 496                        "No support for setting xattr in lower filesystem\n");
 497                 rc = -ENOSYS;
 498                 goto out;
 499         }
 500         xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
 501         if (!xattr_virt) {
 502                 printk(KERN_ERR "Out of memory whilst attempting to write "
 503                        "inode size to xattr\n");
 504                 rc = -ENOMEM;
 505                 goto out;
 506         }
 507         mutex_lock(&lower_inode->i_mutex);
 508         size = lower_inode->i_op->getxattr(lower_dentry, ECRYPTFS_XATTR_NAME,
 509                                            xattr_virt, PAGE_CACHE_SIZE);
 510         if (size < 0)
 511                 size = 8;
 512         file_size = (u64)i_size_read(ecryptfs_inode);
 513         file_size = cpu_to_be64(file_size);
 514         memcpy(xattr_virt, &file_size, sizeof(u64));
 515         rc = lower_inode->i_op->setxattr(lower_dentry, ECRYPTFS_XATTR_NAME,
 516                                          xattr_virt, size, 0);
 517         mutex_unlock(&lower_inode->i_mutex);
 518         if (rc)
 519                 printk(KERN_ERR "Error whilst attempting to write inode size "
 520                        "to lower file xattr; rc = [%d]\n", rc);
 521         kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
 522 out:
 523         return rc;
 524 }
 525
 526 int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode)
 527 {
 528         struct ecryptfs_crypt_stat *crypt_stat;
 529
 530         crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 531         if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 532                 return ecryptfs_write_inode_size_to_xattr(ecryptfs_inode);
 533         else
 534                 return ecryptfs_write_inode_size_to_header(ecryptfs_inode);
 535 }
 536
 537 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
 538                             struct file *lower_file,
 539                             unsigned long lower_page_index, int byte_offset,
 540                             int region_bytes)
 541 {
 542         int rc = 0;
 543
 544         *lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index);
 545         if (!(*lower_page)) {
 546                 rc = -EINVAL;
 547                 ecryptfs_printk(KERN_ERR, "Error attempting to grab "
 548                                 "lower page with index [0x%.16x]\n",
 549                                 lower_page_index);
 550                 goto out;
 551         }
 552         rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
 553                                                           (*lower_page),
 554                                                           byte_offset,
 555                                                           region_bytes);
 556         if (rc) {
 557                 ecryptfs_printk(KERN_ERR, "prepare_write for "
 558                         "lower_page_index = [0x%.16x] failed; rc = "
 559                         "[%d]\n", lower_page_index, rc);
 560                 ecryptfs_release_lower_page(*lower_page);
 561                 (*lower_page) = NULL;
 562         }
 563 out:
 564         return rc;
 565 }
 566
 567 /**
 568  * ecryptfs_commit_lower_page
 569  *
 570  * Returns zero on success; non-zero on error
 571  */
 572 int
 573 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
 574                            struct file *lower_file, int byte_offset,
 575                            int region_size)
 576 {
 577         int rc = 0;
 578
 579         rc = lower_inode->i_mapping->a_ops->commit_write(
 580                 lower_file, lower_page, byte_offset, region_size);
 581         if (rc < 0) {
 582                 ecryptfs_printk(KERN_ERR,
 583                                 "Error committing write; rc = [%d]\n", rc);
 584         } else
 585                 rc = 0;
 586         ecryptfs_release_lower_page(lower_page);
 587         return rc;
 588 }
 589
 590 /**
 591  * ecryptfs_copy_page_to_lower
 592  *
 593  * Used for plaintext pass-through; no page index interpolation
 594  * required.
 595  */
 596 int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
 597                                 struct file *lower_file)
 598 {
 599         int rc = 0;
 600         struct page *lower_page;
 601
 602         rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
 603                                      page->index, 0, PAGE_CACHE_SIZE);
 604         if (rc) {
 605                 ecryptfs_printk(KERN_ERR, "Error attempting to get page "
 606                                 "at index [0x%.16x]\n", page->index);
 607                 goto out;
 608         }
 609         /* TODO: aops */
 610         memcpy((char *)page_address(lower_page), page_address(page),
 611                PAGE_CACHE_SIZE);
 612         rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
 613                                         0, PAGE_CACHE_SIZE);
 614         if (rc)
 615                 ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
 616                                 "at index [0x%.16x]\n", page->index);
 617 out:
 618         return rc;
 619 }
 620
 621 /**
 622  * ecryptfs_commit_write
 623  * @file: The eCryptfs file object
 624  * @page: The eCryptfs page
 625  * @from: Ignored (we rotate the page IV on each write)
 626  * @to: Ignored
 627  *
 628  * This is where we encrypt the data and pass the encrypted data to
 629  * the lower filesystem.  In OpenPGP-compatible mode, we operate on
 630  * entire underlying packets.
 631  */
 632 static int ecryptfs_commit_write(struct file *file, struct page *page,
 633                                  unsigned from, unsigned to)
 634 {
 635         loff_t pos;
 636         struct inode *inode;
 637         struct inode *lower_inode;
 638         struct file *lower_file;
 639         struct ecryptfs_crypt_stat *crypt_stat;
 640         int rc;
 641
 642         inode = page->mapping->host;
 643         lower_inode = ecryptfs_inode_to_lower(inode);
 644         lower_file = ecryptfs_file_to_lower(file);
 645         mutex_lock(&lower_inode->i_mutex);
 646         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
 647                                 ->crypt_stat;
 648         if (crypt_stat->flags & ECRYPTFS_NEW_FILE) {
 649                 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
 650                         "crypt_stat at memory location [%p]\n", crypt_stat);
 651                 crypt_stat->flags &= ~(ECRYPTFS_NEW_FILE);
 652         } else
 653                 ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
 654         ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
 655                         "(page w/ index = [0x%.16x], to = [%d])\n", page->index,
 656                         to);
 657         rc = fill_zeros_to_end_of_page(page, to);
 658         if (rc) {
 659                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
 660                                 "zeros in page with index = [0x%.16x]\n",
 661                                 page->index);
 662                 goto out;
 663         }
 664         rc = ecryptfs_encrypt_page(page);
 665         if (rc) {
 666                 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
 667                                 "index [0x%.16x])\n", page->index);
 668                 goto out;
 669         }
 670         inode->i_blocks = lower_inode->i_blocks;
 671         pos = page_offset(page) + to;
 672         if (pos > i_size_read(inode)) {
 673                 i_size_write(inode, pos);
 674                 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
 675                                 "[0x%.16x]\n", i_size_read(inode));
 676         }
 677         rc = ecryptfs_write_inode_size_to_metadata(inode);
 678         if (rc)
 679                 printk(KERN_ERR "Error writing inode size to metadata; "
 680                        "rc = [%d]\n", rc);
 681         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 682         mark_inode_dirty_sync(inode);
 683 out:
 684         if (rc < 0)
 685                 ClearPageUptodate(page);
 686         else
 687                 SetPageUptodate(page);
 688         mutex_unlock(&lower_inode->i_mutex);
 689         return rc;
 690 }
 691
 692 /**
 693  * ecryptfs_write_zeros
 694  * @file: The ecryptfs file
 695  * @index: The index in which we are writing
 696  * @start: The position after the last block of data
 697  * @num_zeros: The number of zeros to write
 698  *
 699  * Write a specified number of zero's to a page.
 700  *
 701  * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
 702  */
 703 int
 704 ecryptfs_write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
 705 {
 706         int rc = 0;
 707         struct page *tmp_page;
 708
 709         tmp_page = ecryptfs_get1page(file, index);
 710         if (IS_ERR(tmp_page)) {
 711                 ecryptfs_printk(KERN_ERR, "Error getting page at index "
 712                                 "[0x%.16x]\n", index);
 713                 rc = PTR_ERR(tmp_page);
 714                 goto out;
 715         }
 716         rc = ecryptfs_prepare_write_no_truncate(file, tmp_page, start,
 717                                                 (start + num_zeros));
 718         if (rc) {
 719                 ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
 720                                 "to page at index [0x%.16x]\n",
 721                                 index);
 722                 page_cache_release(tmp_page);
 723                 goto out;
 724         }
 725         zero_user_page(tmp_page, start, num_zeros, KM_USER0);
 726         rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
 727         if (rc < 0) {
 728                 ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
 729                                 "to remainder of page at index [0x%.16x]\n",
 730                                 index);
 731                 page_cache_release(tmp_page);
 732                 goto out;
 733         }
 734         rc = 0;
 735         page_cache_release(tmp_page);
 736 out:
 737         return rc;
 738 }
 739
 740 static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
 741 {
 742         int rc = 0;
 743         struct inode *inode;
 744         struct inode *lower_inode;
 745
 746         inode = (struct inode *)mapping->host;
 747         lower_inode = ecryptfs_inode_to_lower(inode);
 748         if (lower_inode->i_mapping->a_ops->bmap)
 749                 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
 750                                                          block);
 751         return rc;
 752 }
 753
 754 static void ecryptfs_sync_page(struct page *page)
 755 {
 756         struct inode *inode;
 757         struct inode *lower_inode;
 758         struct page *lower_page;
 759
 760         inode = page->mapping->host;
 761         lower_inode = ecryptfs_inode_to_lower(inode);
 762         /* NOTE: Recently swapped with grab_cache_page(), since
 763          * sync_page() just makes sure that pending I/O gets done. */
 764         lower_page = find_lock_page(lower_inode->i_mapping, page->index);
 765         if (!lower_page) {
 766                 ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n");
 767                 return;
 768         }
 769         if (lower_page->mapping->a_ops->sync_page)
 770                 lower_page->mapping->a_ops->sync_page(lower_page);
 771         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
 772                         lower_page->index);
 773         unlock_page(lower_page);
 774         page_cache_release(lower_page);
 775 }
 776
 777 struct address_space_operations ecryptfs_aops = {
 778         .writepage = ecryptfs_writepage,
 779         .readpage = ecryptfs_readpage,
 780         .prepare_write = ecryptfs_prepare_write,
 781         .commit_write = ecryptfs_commit_write,
 782         .bmap = ecryptfs_bmap,
 783         .sync_page = ecryptfs_sync_page,
 784 };