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