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 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 static 60 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros); 61 62 /** 63 * ecryptfs_fill_zeros 64 * @file: The ecryptfs file 65 * @new_length: The new length of the data in the underlying file; 66 * everything between the prior end of the file and the 67 * new end of the file will be filled with zero's. 68 * new_length must be greater than current length 69 * 70 * Function for handling lseek-ing past the end of the file. 71 * 72 * This function does not support shrinking, only growing a file. 73 * 74 * Returns zero on success; non-zero otherwise. 75 */ 76 int ecryptfs_fill_zeros(struct file *file, loff_t new_length) 77 { 78 int rc = 0; 79 struct dentry *dentry = file->f_path.dentry; 80 struct inode *inode = dentry->d_inode; 81 pgoff_t old_end_page_index = 0; 82 pgoff_t index = old_end_page_index; 83 int old_end_pos_in_page = -1; 84 pgoff_t new_end_page_index; 85 int new_end_pos_in_page; 86 loff_t cur_length = i_size_read(inode); 87 88 if (cur_length != 0) { 89 index = old_end_page_index = 90 ((cur_length - 1) >> PAGE_CACHE_SHIFT); 91 old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK); 92 } 93 new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT); 94 new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK); 95 ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; " 96 "old_end_pos_in_page = [%d]; " 97 "new_end_page_index = [0x%.16x]; " 98 "new_end_pos_in_page = [%d]\n", 99 old_end_page_index, old_end_pos_in_page, 100 new_end_page_index, new_end_pos_in_page); 101 if (old_end_page_index == new_end_page_index) { 102 /* Start and end are in the same page; we just need to 103 * set a portion of the existing page to zero's */ 104 rc = write_zeros(file, index, (old_end_pos_in_page + 1), 105 (new_end_pos_in_page - old_end_pos_in_page)); 106 if (rc) 107 ecryptfs_printk(KERN_ERR, "write_zeros(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 = 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, "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 = write_zeros(file, index, 0, PAGE_CACHE_SIZE); 135 if (rc) { 136 ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], " 137 "index=[0x%.16x], " 138 "old_end_pos_in_page=[d], " 139 "(PAGE_CACHE_SIZE - new_end_pos_in_page" 140 "=[%d]" 141 ")=[d]) returned [%d]\n", file, index, 142 old_end_pos_in_page, 143 new_end_pos_in_page, 144 (PAGE_CACHE_SIZE - new_end_pos_in_page), 145 rc); 146 goto out; 147 } 148 index++; 149 } 150 /* Fill the portion at the beginning of the last new page with 151 * zero's */ 152 rc = write_zeros(file, index, 0, (new_end_pos_in_page + 1)); 153 if (rc) { 154 ecryptfs_printk(KERN_ERR, "write_zeros(file=" 155 "[%p], index=[0x%.16x], 0, " 156 "new_end_pos_in_page=[%d]" 157 "returned [%d]\n", file, index, 158 new_end_pos_in_page, rc); 159 goto out; 160 } 161 out: 162 return rc; 163 } 164 165 /** 166 * ecryptfs_writepage 167 * @page: Page that is locked before this call is made 168 * 169 * Returns zero on success; non-zero otherwise 170 */ 171 static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc) 172 { 173 struct ecryptfs_page_crypt_context ctx; 174 int rc; 175 176 ctx.page = page; 177 ctx.mode = ECRYPTFS_WRITEPAGE_MODE; 178 ctx.param.wbc = wbc; 179 rc = ecryptfs_encrypt_page(&ctx); 180 if (rc) { 181 ecryptfs_printk(KERN_WARNING, "Error encrypting " 182 "page (upper index [0x%.16x])\n", page->index); 183 ClearPageUptodate(page); 184 goto out; 185 } 186 SetPageUptodate(page); 187 unlock_page(page); 188 out: 189 return rc; 190 } 191 192 /** 193 * Reads the data from the lower file file at index lower_page_index 194 * and copies that data into page. 195 * 196 * @param page Page to fill 197 * @param lower_page_index Index of the page in the lower file to get 198 */ 199 int ecryptfs_do_readpage(struct file *file, struct page *page, 200 pgoff_t lower_page_index) 201 { 202 int rc; 203 struct dentry *dentry; 204 struct file *lower_file; 205 struct dentry *lower_dentry; 206 struct inode *inode; 207 struct inode *lower_inode; 208 char *page_data; 209 struct page *lower_page = NULL; 210 char *lower_page_data; 211 const struct address_space_operations *lower_a_ops; 212 213 dentry = file->f_path.dentry; 214 lower_file = ecryptfs_file_to_lower(file); 215 lower_dentry = ecryptfs_dentry_to_lower(dentry); 216 inode = dentry->d_inode; 217 lower_inode = ecryptfs_inode_to_lower(inode); 218 lower_a_ops = lower_inode->i_mapping->a_ops; 219 lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index, 220 (filler_t *)lower_a_ops->readpage, 221 (void *)lower_file); 222 if (IS_ERR(lower_page)) { 223 rc = PTR_ERR(lower_page); 224 lower_page = NULL; 225 ecryptfs_printk(KERN_ERR, "Error reading from page cache\n"); 226 goto out; 227 } 228 page_data = kmap_atomic(page, KM_USER0); 229 lower_page_data = kmap_atomic(lower_page, KM_USER1); 230 memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE); 231 kunmap_atomic(lower_page_data, KM_USER1); 232 kunmap_atomic(page_data, KM_USER0); 233 flush_dcache_page(page); 234 rc = 0; 235 out: 236 if (likely(lower_page)) 237 page_cache_release(lower_page); 238 if (rc == 0) 239 SetPageUptodate(page); 240 else 241 ClearPageUptodate(page); 242 return rc; 243 } 244 /** 245 * Header Extent: 246 * Octets 0-7: Unencrypted file size (big-endian) 247 * Octets 8-15: eCryptfs special marker 248 * Octets 16-19: Flags 249 * Octet 16: File format version number (between 0 and 255) 250 * Octets 17-18: Reserved 251 * Octet 19: Bit 1 (lsb): Reserved 252 * Bit 2: Encrypted? 253 * Bits 3-8: Reserved 254 * Octets 20-23: Header extent size (big-endian) 255 * Octets 24-25: Number of header extents at front of file 256 * (big-endian) 257 * Octet 26: Begin RFC 2440 authentication token packet set 258 */ 259 static void set_header_info(char *page_virt, 260 struct ecryptfs_crypt_stat *crypt_stat) 261 { 262 size_t written; 263 int save_num_header_extents_at_front = 264 crypt_stat->num_header_extents_at_front; 265 266 crypt_stat->num_header_extents_at_front = 1; 267 ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written); 268 crypt_stat->num_header_extents_at_front = 269 save_num_header_extents_at_front; 270 } 271 272 /** 273 * ecryptfs_readpage 274 * @file: This is an ecryptfs file 275 * @page: ecryptfs associated page to stick the read data into 276 * 277 * Read in a page, decrypting if necessary. 278 * 279 * Returns zero on success; non-zero on error. 280 */ 281 static int ecryptfs_readpage(struct file *file, struct page *page) 282 { 283 int rc = 0; 284 struct ecryptfs_crypt_stat *crypt_stat; 285 286 BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode)); 287 crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode) 288 ->crypt_stat; 289 if (!crypt_stat 290 || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED) 291 || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) { 292 ecryptfs_printk(KERN_DEBUG, 293 "Passing through unencrypted page\n"); 294 rc = ecryptfs_do_readpage(file, page, page->index); 295 if (rc) { 296 ecryptfs_printk(KERN_ERR, "Error reading page; rc = " 297 "[%d]\n", rc); 298 goto out; 299 } 300 } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) { 301 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) { 302 int num_pages_in_header_region = 303 (crypt_stat->header_extent_size 304 / PAGE_CACHE_SIZE); 305 306 if (page->index < num_pages_in_header_region) { 307 char *page_virt; 308 309 page_virt = kmap_atomic(page, KM_USER0); 310 memset(page_virt, 0, PAGE_CACHE_SIZE); 311 if (page->index == 0) { 312 rc = ecryptfs_read_xattr_region( 313 page_virt, file->f_path.dentry); 314 set_header_info(page_virt, crypt_stat); 315 } 316 kunmap_atomic(page_virt, KM_USER0); 317 flush_dcache_page(page); 318 if (rc) { 319 printk(KERN_ERR "Error reading xattr " 320 "region\n"); 321 goto out; 322 } 323 } else { 324 rc = ecryptfs_do_readpage( 325 file, page, 326 (page->index 327 - num_pages_in_header_region)); 328 if (rc) { 329 printk(KERN_ERR "Error reading page; " 330 "rc = [%d]\n", rc); 331 goto out; 332 } 333 } 334 } else { 335 rc = ecryptfs_do_readpage(file, page, page->index); 336 if (rc) { 337 printk(KERN_ERR "Error reading page; rc = " 338 "[%d]\n", rc); 339 goto out; 340 } 341 } 342 } else { 343 rc = ecryptfs_decrypt_page(file, page); 344 if (rc) { 345 ecryptfs_printk(KERN_ERR, "Error decrypting page; " 346 "rc = [%d]\n", rc); 347 goto out; 348 } 349 } 350 SetPageUptodate(page); 351 out: 352 if (rc) 353 ClearPageUptodate(page); 354 ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", 355 page->index); 356 unlock_page(page); 357 return rc; 358 } 359 360 /** 361 * Called with lower inode mutex held. 362 */ 363 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to) 364 { 365 struct inode *inode = page->mapping->host; 366 int end_byte_in_page; 367 368 if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index) 369 goto out; 370 end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE; 371 if (to > end_byte_in_page) 372 end_byte_in_page = to; 373 zero_user_page(page, end_byte_in_page, 374 PAGE_CACHE_SIZE - end_byte_in_page, KM_USER0); 375 out: 376 return 0; 377 } 378 379 /** 380 * eCryptfs does not currently support holes. When writing after a 381 * seek past the end of the file, eCryptfs fills in 0's through to the 382 * current location. The code to fill in the 0's to all the 383 * intermediate pages calls ecryptfs_prepare_write_no_truncate(). 384 */ 385 static int 386 ecryptfs_prepare_write_no_truncate(struct file *file, struct page *page, 387 unsigned from, unsigned to) 388 { 389 int rc = 0; 390 391 if (from == 0 && to == PAGE_CACHE_SIZE) 392 goto out; /* If we are writing a full page, it will be 393 up to date. */ 394 if (!PageUptodate(page)) 395 rc = ecryptfs_do_readpage(file, page, page->index); 396 out: 397 return rc; 398 } 399 400 static int ecryptfs_prepare_write(struct file *file, struct page *page, 401 unsigned from, unsigned to) 402 { 403 loff_t pos; 404 int rc = 0; 405 406 if (from == 0 && to == PAGE_CACHE_SIZE) 407 goto out; /* If we are writing a full page, it will be 408 up to date. */ 409 if (!PageUptodate(page)) 410 rc = ecryptfs_do_readpage(file, page, page->index); 411 pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; 412 if (pos > i_size_read(page->mapping->host)) { 413 rc = ecryptfs_truncate(file->f_path.dentry, pos); 414 if (rc) { 415 printk(KERN_ERR "Error on attempt to " 416 "truncate to (higher) offset [%lld];" 417 " rc = [%d]\n", pos, rc); 418 goto out; 419 } 420 } 421 out: 422 return rc; 423 } 424 425 int ecryptfs_writepage_and_release_lower_page(struct page *lower_page, 426 struct inode *lower_inode, 427 struct writeback_control *wbc) 428 { 429 int rc = 0; 430 431 rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc); 432 if (rc) { 433 ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); " 434 "rc = [%d]\n", rc); 435 goto out; 436 } 437 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; 438 page_cache_release(lower_page); 439 out: 440 return rc; 441 } 442 443 static 444 void ecryptfs_release_lower_page(struct page *lower_page, int page_locked) 445 { 446 if (page_locked) 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 file *lower_file, 459 struct inode *lower_inode, 460 struct inode *inode) 461 { 462 int rc = 0; 463 struct page *header_page; 464 char *header_virt; 465 const struct address_space_operations *lower_a_ops; 466 u64 file_size; 467 468 retry: 469 header_page = grab_cache_page(lower_inode->i_mapping, 0); 470 if (!header_page) { 471 ecryptfs_printk(KERN_ERR, "grab_cache_page for " 472 "lower_page_index 0 failed\n"); 473 rc = -EINVAL; 474 goto out; 475 } 476 lower_a_ops = lower_inode->i_mapping->a_ops; 477 rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8); 478 if (rc) { 479 if (rc == AOP_TRUNCATED_PAGE) { 480 ecryptfs_release_lower_page(header_page, 0); 481 goto retry; 482 } else 483 ecryptfs_release_lower_page(header_page, 1); 484 goto out; 485 } 486 file_size = (u64)i_size_read(inode); 487 ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size); 488 file_size = cpu_to_be64(file_size); 489 header_virt = kmap_atomic(header_page, KM_USER0); 490 memcpy(header_virt, &file_size, sizeof(u64)); 491 kunmap_atomic(header_virt, KM_USER0); 492 flush_dcache_page(header_page); 493 rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8); 494 if (rc < 0) 495 ecryptfs_printk(KERN_ERR, "Error commiting header page " 496 "write\n"); 497 if (rc == AOP_TRUNCATED_PAGE) { 498 ecryptfs_release_lower_page(header_page, 0); 499 goto retry; 500 } else 501 ecryptfs_release_lower_page(header_page, 1); 502 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; 503 mark_inode_dirty_sync(inode); 504 out: 505 return rc; 506 } 507 508 static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode, 509 struct inode *inode, 510 struct dentry *ecryptfs_dentry, 511 int lower_i_mutex_held) 512 { 513 ssize_t size; 514 void *xattr_virt; 515 struct dentry *lower_dentry; 516 u64 file_size; 517 int rc; 518 519 xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL); 520 if (!xattr_virt) { 521 printk(KERN_ERR "Out of memory whilst attempting to write " 522 "inode size to xattr\n"); 523 rc = -ENOMEM; 524 goto out; 525 } 526 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); 527 if (!lower_dentry->d_inode->i_op->getxattr || 528 !lower_dentry->d_inode->i_op->setxattr) { 529 printk(KERN_WARNING 530 "No support for setting xattr in lower filesystem\n"); 531 rc = -ENOSYS; 532 kmem_cache_free(ecryptfs_xattr_cache, xattr_virt); 533 goto out; 534 } 535 if (!lower_i_mutex_held) 536 mutex_lock(&lower_dentry->d_inode->i_mutex); 537 size = lower_dentry->d_inode->i_op->getxattr(lower_dentry, 538 ECRYPTFS_XATTR_NAME, 539 xattr_virt, 540 PAGE_CACHE_SIZE); 541 if (!lower_i_mutex_held) 542 mutex_unlock(&lower_dentry->d_inode->i_mutex); 543 if (size < 0) 544 size = 8; 545 file_size = (u64)i_size_read(inode); 546 file_size = cpu_to_be64(file_size); 547 memcpy(xattr_virt, &file_size, sizeof(u64)); 548 if (!lower_i_mutex_held) 549 mutex_lock(&lower_dentry->d_inode->i_mutex); 550 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, 551 ECRYPTFS_XATTR_NAME, 552 xattr_virt, size, 0); 553 if (!lower_i_mutex_held) 554 mutex_unlock(&lower_dentry->d_inode->i_mutex); 555 if (rc) 556 printk(KERN_ERR "Error whilst attempting to write inode size " 557 "to lower file xattr; rc = [%d]\n", rc); 558 kmem_cache_free(ecryptfs_xattr_cache, xattr_virt); 559 out: 560 return rc; 561 } 562 563 int 564 ecryptfs_write_inode_size_to_metadata(struct file *lower_file, 565 struct inode *lower_inode, 566 struct inode *inode, 567 struct dentry *ecryptfs_dentry, 568 int lower_i_mutex_held) 569 { 570 struct ecryptfs_crypt_stat *crypt_stat; 571 572 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; 573 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) 574 return ecryptfs_write_inode_size_to_xattr(lower_inode, inode, 575 ecryptfs_dentry, 576 lower_i_mutex_held); 577 else 578 return ecryptfs_write_inode_size_to_header(lower_file, 579 lower_inode, 580 inode); 581 } 582 583 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode, 584 struct file *lower_file, 585 unsigned long lower_page_index, int byte_offset, 586 int region_bytes) 587 { 588 int rc = 0; 589 590 retry: 591 *lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index); 592 if (!(*lower_page)) { 593 rc = -EINVAL; 594 ecryptfs_printk(KERN_ERR, "Error attempting to grab " 595 "lower page with index [0x%.16x]\n", 596 lower_page_index); 597 goto out; 598 } 599 rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file, 600 (*lower_page), 601 byte_offset, 602 region_bytes); 603 if (rc) { 604 if (rc == AOP_TRUNCATED_PAGE) { 605 ecryptfs_release_lower_page(*lower_page, 0); 606 goto retry; 607 } else { 608 ecryptfs_printk(KERN_ERR, "prepare_write for " 609 "lower_page_index = [0x%.16x] failed; rc = " 610 "[%d]\n", lower_page_index, rc); 611 ecryptfs_release_lower_page(*lower_page, 1); 612 (*lower_page) = NULL; 613 } 614 } 615 out: 616 return rc; 617 } 618 619 /** 620 * ecryptfs_commit_lower_page 621 * 622 * Returns zero on success; non-zero on error 623 */ 624 int 625 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode, 626 struct file *lower_file, int byte_offset, 627 int region_size) 628 { 629 int page_locked = 1; 630 int rc = 0; 631 632 rc = lower_inode->i_mapping->a_ops->commit_write( 633 lower_file, lower_page, byte_offset, region_size); 634 if (rc == AOP_TRUNCATED_PAGE) 635 page_locked = 0; 636 if (rc < 0) { 637 ecryptfs_printk(KERN_ERR, 638 "Error committing write; rc = [%d]\n", rc); 639 } else 640 rc = 0; 641 ecryptfs_release_lower_page(lower_page, page_locked); 642 return rc; 643 } 644 645 /** 646 * ecryptfs_copy_page_to_lower 647 * 648 * Used for plaintext pass-through; no page index interpolation 649 * required. 650 */ 651 int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode, 652 struct file *lower_file) 653 { 654 int rc = 0; 655 struct page *lower_page; 656 657 rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file, 658 page->index, 0, PAGE_CACHE_SIZE); 659 if (rc) { 660 ecryptfs_printk(KERN_ERR, "Error attempting to get page " 661 "at index [0x%.16x]\n", page->index); 662 goto out; 663 } 664 /* TODO: aops */ 665 memcpy((char *)page_address(lower_page), page_address(page), 666 PAGE_CACHE_SIZE); 667 rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file, 668 0, PAGE_CACHE_SIZE); 669 if (rc) 670 ecryptfs_printk(KERN_ERR, "Error attempting to commit page " 671 "at index [0x%.16x]\n", page->index); 672 out: 673 return rc; 674 } 675 676 struct kmem_cache *ecryptfs_xattr_cache; 677 678 /** 679 * ecryptfs_commit_write 680 * @file: The eCryptfs file object 681 * @page: The eCryptfs page 682 * @from: Ignored (we rotate the page IV on each write) 683 * @to: Ignored 684 * 685 * This is where we encrypt the data and pass the encrypted data to 686 * the lower filesystem. In OpenPGP-compatible mode, we operate on 687 * entire underlying packets. 688 */ 689 static int ecryptfs_commit_write(struct file *file, struct page *page, 690 unsigned from, unsigned to) 691 { 692 struct ecryptfs_page_crypt_context ctx; 693 loff_t pos; 694 struct inode *inode; 695 struct inode *lower_inode; 696 struct file *lower_file; 697 struct ecryptfs_crypt_stat *crypt_stat; 698 int rc; 699 700 inode = page->mapping->host; 701 lower_inode = ecryptfs_inode_to_lower(inode); 702 lower_file = ecryptfs_file_to_lower(file); 703 mutex_lock(&lower_inode->i_mutex); 704 crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode) 705 ->crypt_stat; 706 if (crypt_stat->flags & ECRYPTFS_NEW_FILE) { 707 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in " 708 "crypt_stat at memory location [%p]\n", crypt_stat); 709 crypt_stat->flags &= ~(ECRYPTFS_NEW_FILE); 710 } else 711 ecryptfs_printk(KERN_DEBUG, "Not a new file\n"); 712 ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page" 713 "(page w/ index = [0x%.16x], to = [%d])\n", page->index, 714 to); 715 rc = fill_zeros_to_end_of_page(page, to); 716 if (rc) { 717 ecryptfs_printk(KERN_WARNING, "Error attempting to fill " 718 "zeros in page with index = [0x%.16x]\n", 719 page->index); 720 goto out; 721 } 722 ctx.page = page; 723 ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE; 724 ctx.param.lower_file = lower_file; 725 rc = ecryptfs_encrypt_page(&ctx); 726 if (rc) { 727 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper " 728 "index [0x%.16x])\n", page->index); 729 goto out; 730 } 731 inode->i_blocks = lower_inode->i_blocks; 732 pos = (page->index << PAGE_CACHE_SHIFT) + to; 733 if (pos > i_size_read(inode)) { 734 i_size_write(inode, pos); 735 ecryptfs_printk(KERN_DEBUG, "Expanded file size to " 736 "[0x%.16x]\n", i_size_read(inode)); 737 } 738 rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode, 739 inode, file->f_dentry, 740 ECRYPTFS_LOWER_I_MUTEX_HELD); 741 if (rc) 742 printk(KERN_ERR "Error writing inode size to metadata; " 743 "rc = [%d]\n", rc); 744 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; 745 mark_inode_dirty_sync(inode); 746 out: 747 if (rc < 0) 748 ClearPageUptodate(page); 749 else 750 SetPageUptodate(page); 751 mutex_unlock(&lower_inode->i_mutex); 752 return rc; 753 } 754 755 /** 756 * write_zeros 757 * @file: The ecryptfs file 758 * @index: The index in which we are writing 759 * @start: The position after the last block of data 760 * @num_zeros: The number of zeros to write 761 * 762 * Write a specified number of zero's to a page. 763 * 764 * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE 765 */ 766 static 767 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros) 768 { 769 int rc = 0; 770 struct page *tmp_page; 771 772 tmp_page = ecryptfs_get1page(file, index); 773 if (IS_ERR(tmp_page)) { 774 ecryptfs_printk(KERN_ERR, "Error getting page at index " 775 "[0x%.16x]\n", index); 776 rc = PTR_ERR(tmp_page); 777 goto out; 778 } 779 if ((rc = ecryptfs_prepare_write_no_truncate(file, tmp_page, start, 780 (start + num_zeros)))) { 781 ecryptfs_printk(KERN_ERR, "Error preparing to write zero's " 782 "to page at index [0x%.16x]\n", 783 index); 784 page_cache_release(tmp_page); 785 goto out; 786 } 787 zero_user_page(tmp_page, start, num_zeros, KM_USER0); 788 rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros); 789 if (rc < 0) { 790 ecryptfs_printk(KERN_ERR, "Error attempting to write zero's " 791 "to remainder of page at index [0x%.16x]\n", 792 index); 793 page_cache_release(tmp_page); 794 goto out; 795 } 796 rc = 0; 797 page_cache_release(tmp_page); 798 out: 799 return rc; 800 } 801 802 static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block) 803 { 804 int rc = 0; 805 struct inode *inode; 806 struct inode *lower_inode; 807 808 inode = (struct inode *)mapping->host; 809 lower_inode = ecryptfs_inode_to_lower(inode); 810 if (lower_inode->i_mapping->a_ops->bmap) 811 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping, 812 block); 813 return rc; 814 } 815 816 static void ecryptfs_sync_page(struct page *page) 817 { 818 struct inode *inode; 819 struct inode *lower_inode; 820 struct page *lower_page; 821 822 inode = page->mapping->host; 823 lower_inode = ecryptfs_inode_to_lower(inode); 824 /* NOTE: Recently swapped with grab_cache_page(), since 825 * sync_page() just makes sure that pending I/O gets done. */ 826 lower_page = find_lock_page(lower_inode->i_mapping, page->index); 827 if (!lower_page) { 828 ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n"); 829 return; 830 } 831 lower_page->mapping->a_ops->sync_page(lower_page); 832 ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", 833 lower_page->index); 834 unlock_page(lower_page); 835 page_cache_release(lower_page); 836 } 837 838 struct address_space_operations ecryptfs_aops = { 839 .writepage = ecryptfs_writepage, 840 .readpage = ecryptfs_readpage, 841 .prepare_write = ecryptfs_prepare_write, 842 .commit_write = ecryptfs_commit_write, 843 .bmap = ecryptfs_bmap, 844 .sync_page = ecryptfs_sync_page, 845 }; 846