1/* 2 * linux/fs/isofs/rock.c 3 * 4 * (C) 1992, 1993 Eric Youngdale 5 * 6 * Rock Ridge Extensions to iso9660 7 */ 8 9#include <linux/slab.h> 10#include <linux/pagemap.h> 11#include <linux/smp_lock.h> 12 13#include "isofs.h" 14#include "rock.h" 15 16/* 17 * These functions are designed to read the system areas of a directory record 18 * and extract relevant information. There are different functions provided 19 * depending upon what information we need at the time. One function fills 20 * out an inode structure, a second one extracts a filename, a third one 21 * returns a symbolic link name, and a fourth one returns the extent number 22 * for the file. 23 */ 24 25#define SIG(A,B) ((A) | ((B) << 8)) /* isonum_721() */ 26 27struct rock_state { 28 void *buffer; 29 unsigned char *chr; 30 int len; 31 int cont_size; 32 int cont_extent; 33 int cont_offset; 34 struct inode *inode; 35}; 36 37/* 38 * This is a way of ensuring that we have something in the system 39 * use fields that is compatible with Rock Ridge. Return zero on success. 40 */ 41 42static int check_sp(struct rock_ridge *rr, struct inode *inode) 43{ 44 if (rr->u.SP.magic[0] != 0xbe) 45 return -1; 46 if (rr->u.SP.magic[1] != 0xef) 47 return -1; 48 ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip; 49 return 0; 50} 51 52static void setup_rock_ridge(struct iso_directory_record *de, 53 struct inode *inode, struct rock_state *rs) 54{ 55 rs->len = sizeof(struct iso_directory_record) + de->name_len[0]; 56 if (rs->len & 1) 57 (rs->len)++; 58 rs->chr = (unsigned char *)de + rs->len; 59 rs->len = *((unsigned char *)de) - rs->len; 60 if (rs->len < 0) 61 rs->len = 0; 62 63 if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) { 64 rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset; 65 rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset; 66 if (rs->len < 0) 67 rs->len = 0; 68 } 69} 70 71static void init_rock_state(struct rock_state *rs, struct inode *inode) 72{ 73 memset(rs, 0, sizeof(*rs)); 74 rs->inode = inode; 75} 76 77/* 78 * Returns 0 if the caller should continue scanning, 1 if the scan must end 79 * and -ve on error. 80 */ 81static int rock_continue(struct rock_state *rs) 82{ 83 int ret = 1; 84 int blocksize = 1 << rs->inode->i_blkbits; 85 const int min_de_size = offsetof(struct rock_ridge, u); 86 87 kfree(rs->buffer); 88 rs->buffer = NULL; 89 90 if ((unsigned)rs->cont_offset > blocksize - min_de_size || 91 (unsigned)rs->cont_size > blocksize || 92 (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) { 93 printk(KERN_NOTICE "rock: corrupted directory entry. " 94 "extent=%d, offset=%d, size=%d\n", 95 rs->cont_extent, rs->cont_offset, rs->cont_size); 96 ret = -EIO; 97 goto out; 98 } 99 100 if (rs->cont_extent) { 101 struct buffer_head *bh; 102 103 rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL); 104 if (!rs->buffer) { 105 ret = -ENOMEM; 106 goto out; 107 } 108 ret = -EIO; 109 bh = sb_bread(rs->inode->i_sb, rs->cont_extent); 110 if (bh) { 111 memcpy(rs->buffer, bh->b_data + rs->cont_offset, 112 rs->cont_size); 113 put_bh(bh); 114 rs->chr = rs->buffer; 115 rs->len = rs->cont_size; 116 rs->cont_extent = 0; 117 rs->cont_size = 0; 118 rs->cont_offset = 0; 119 return 0; 120 } 121 printk("Unable to read rock-ridge attributes\n"); 122 } 123out: 124 kfree(rs->buffer); 125 rs->buffer = NULL; 126 return ret; 127} 128 129/* 130 * We think there's a record of type `sig' at rs->chr. Parse the signature 131 * and make sure that there's really room for a record of that type. 132 */ 133static int rock_check_overflow(struct rock_state *rs, int sig) 134{ 135 int len; 136 137 switch (sig) { 138 case SIG('S', 'P'): 139 len = sizeof(struct SU_SP_s); 140 break; 141 case SIG('C', 'E'): 142 len = sizeof(struct SU_CE_s); 143 break; 144 case SIG('E', 'R'): 145 len = sizeof(struct SU_ER_s); 146 break; 147 case SIG('R', 'R'): 148 len = sizeof(struct RR_RR_s); 149 break; 150 case SIG('P', 'X'): 151 len = sizeof(struct RR_PX_s); 152 break; 153 case SIG('P', 'N'): 154 len = sizeof(struct RR_PN_s); 155 break; 156 case SIG('S', 'L'): 157 len = sizeof(struct RR_SL_s); 158 break; 159 case SIG('N', 'M'): 160 len = sizeof(struct RR_NM_s); 161 break; 162 case SIG('C', 'L'): 163 len = sizeof(struct RR_CL_s); 164 break; 165 case SIG('P', 'L'): 166 len = sizeof(struct RR_PL_s); 167 break; 168 case SIG('T', 'F'): 169 len = sizeof(struct RR_TF_s); 170 break; 171 case SIG('Z', 'F'): 172 len = sizeof(struct RR_ZF_s); 173 break; 174 default: 175 len = 0; 176 break; 177 } 178 len += offsetof(struct rock_ridge, u); 179 if (len > rs->len) { 180 printk(KERN_NOTICE "rock: directory entry would overflow " 181 "storage\n"); 182 printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n", 183 sig, len, rs->len); 184 return -EIO; 185 } 186 return 0; 187} 188 189/* 190 * return length of name field; 0: not found, -1: to be ignored 191 */ 192int get_rock_ridge_filename(struct iso_directory_record *de, 193 char *retname, struct inode *inode) 194{ 195 struct rock_state rs; 196 struct rock_ridge *rr; 197 int sig; 198 int retnamlen = 0; 199 int truncate = 0; 200 int ret = 0; 201 202 if (!ISOFS_SB(inode->i_sb)->s_rock) 203 return 0; 204 *retname = 0; 205 206 init_rock_state(&rs, inode); 207 setup_rock_ridge(de, inode, &rs); 208repeat: 209 210 while (rs.len > 2) { /* There may be one byte for padding somewhere */ 211 rr = (struct rock_ridge *)rs.chr; 212 if (rr->len < 3) 213 goto out; /* Something got screwed up here */ 214 sig = isonum_721(rs.chr); 215 if (rock_check_overflow(&rs, sig)) 216 goto eio; 217 rs.chr += rr->len; 218 rs.len -= rr->len; 219 if (rs.len < 0) 220 goto eio; /* corrupted isofs */ 221 222 switch (sig) { 223 case SIG('R', 'R'): 224 if ((rr->u.RR.flags[0] & RR_NM) == 0) 225 goto out; 226 break; 227 case SIG('S', 'P'): 228 if (check_sp(rr, inode)) 229 goto out; 230 break; 231 case SIG('C', 'E'): 232 rs.cont_extent = isonum_733(rr->u.CE.extent); 233 rs.cont_offset = isonum_733(rr->u.CE.offset); 234 rs.cont_size = isonum_733(rr->u.CE.size); 235 break; 236 case SIG('N', 'M'): 237 if (truncate) 238 break; 239 if (rr->len < 5) 240 break; 241 /* 242 * If the flags are 2 or 4, this indicates '.' or '..'. 243 * We don't want to do anything with this, because it 244 * screws up the code that calls us. We don't really 245 * care anyways, since we can just use the non-RR 246 * name. 247 */ 248 if (rr->u.NM.flags & 6) 249 break; 250 251 if (rr->u.NM.flags & ~1) { 252 printk("Unsupported NM flag settings (%d)\n", 253 rr->u.NM.flags); 254 break; 255 } 256 if ((strlen(retname) + rr->len - 5) >= 254) { 257 truncate = 1; 258 break; 259 } 260 strncat(retname, rr->u.NM.name, rr->len - 5); 261 retnamlen += rr->len - 5; 262 break; 263 case SIG('R', 'E'): 264 kfree(rs.buffer); 265 return -1; 266 default: 267 break; 268 } 269 } 270 ret = rock_continue(&rs); 271 if (ret == 0) 272 goto repeat; 273 if (ret == 1) 274 return retnamlen; /* If 0, this file did not have a NM field */ 275out: 276 kfree(rs.buffer); 277 return ret; 278eio: 279 ret = -EIO; 280 goto out; 281} 282 283static int 284parse_rock_ridge_inode_internal(struct iso_directory_record *de, 285 struct inode *inode, int regard_xa) 286{ 287 int symlink_len = 0; 288 int cnt, sig; 289 struct inode *reloc; 290 struct rock_ridge *rr; 291 int rootflag; 292 struct rock_state rs; 293 int ret = 0; 294 295 if (!ISOFS_SB(inode->i_sb)->s_rock) 296 return 0; 297 298 init_rock_state(&rs, inode); 299 setup_rock_ridge(de, inode, &rs); 300 if (regard_xa) { 301 rs.chr += 14; 302 rs.len -= 14; 303 if (rs.len < 0) 304 rs.len = 0; 305 } 306 307repeat: 308 while (rs.len > 2) { /* There may be one byte for padding somewhere */ 309 rr = (struct rock_ridge *)rs.chr; 310 if (rr->len < 3) 311 goto out; /* Something got screwed up here */ 312 sig = isonum_721(rs.chr); 313 if (rock_check_overflow(&rs, sig)) 314 goto eio; 315 rs.chr += rr->len; 316 rs.len -= rr->len; 317 if (rs.len < 0) 318 goto eio; /* corrupted isofs */ 319 320 switch (sig) { 321#ifndef CONFIG_ZISOFS /* No flag for SF or ZF */ 322 case SIG('R', 'R'): 323 if ((rr->u.RR.flags[0] & 324 (RR_PX | RR_TF | RR_SL | RR_CL)) == 0) 325 goto out; 326 break; 327#endif 328 case SIG('S', 'P'): 329 if (check_sp(rr, inode)) 330 goto out; 331 break; 332 case SIG('C', 'E'): 333 rs.cont_extent = isonum_733(rr->u.CE.extent); 334 rs.cont_offset = isonum_733(rr->u.CE.offset); 335 rs.cont_size = isonum_733(rr->u.CE.size); 336 break; 337 case SIG('E', 'R'): 338 ISOFS_SB(inode->i_sb)->s_rock = 1; 339 printk(KERN_DEBUG "ISO 9660 Extensions: "); 340 { 341 int p; 342 for (p = 0; p < rr->u.ER.len_id; p++) 343 printk("%c", rr->u.ER.data[p]); 344 } 345 printk("\n"); 346 break; 347 case SIG('P', 'X'): 348 inode->i_mode = isonum_733(rr->u.PX.mode); 349 inode->i_nlink = isonum_733(rr->u.PX.n_links); 350 inode->i_uid = isonum_733(rr->u.PX.uid); 351 inode->i_gid = isonum_733(rr->u.PX.gid); 352 break; 353 case SIG('P', 'N'): 354 { 355 int high, low; 356 high = isonum_733(rr->u.PN.dev_high); 357 low = isonum_733(rr->u.PN.dev_low); 358 /* 359 * The Rock Ridge standard specifies that if 360 * sizeof(dev_t) <= 4, then the high field is 361 * unused, and the device number is completely 362 * stored in the low field. Some writers may 363 * ignore this subtlety, 364 * and as a result we test to see if the entire 365 * device number is 366 * stored in the low field, and use that. 367 */ 368 if ((low & ~0xff) && high == 0) { 369 inode->i_rdev = 370 MKDEV(low >> 8, low & 0xff); 371 } else { 372 inode->i_rdev = 373 MKDEV(high, low); 374 } 375 } 376 break; 377 case SIG('T', 'F'): 378 /* 379 * Some RRIP writers incorrectly place ctime in the 380 * TF_CREATE field. Try to handle this correctly for 381 * either case. 382 */ 383 /* Rock ridge never appears on a High Sierra disk */ 384 cnt = 0; 385 if (rr->u.TF.flags & TF_CREATE) { 386 inode->i_ctime.tv_sec = 387 iso_date(rr->u.TF.times[cnt++].time, 388 0); 389 inode->i_ctime.tv_nsec = 0; 390 } 391 if (rr->u.TF.flags & TF_MODIFY) { 392 inode->i_mtime.tv_sec = 393 iso_date(rr->u.TF.times[cnt++].time, 394 0); 395 inode->i_mtime.tv_nsec = 0; 396 } 397 if (rr->u.TF.flags & TF_ACCESS) { 398 inode->i_atime.tv_sec = 399 iso_date(rr->u.TF.times[cnt++].time, 400 0); 401 inode->i_atime.tv_nsec = 0; 402 } 403 if (rr->u.TF.flags & TF_ATTRIBUTES) { 404 inode->i_ctime.tv_sec = 405 iso_date(rr->u.TF.times[cnt++].time, 406 0); 407 inode->i_ctime.tv_nsec = 0; 408 } 409 break; 410 case SIG('S', 'L'): 411 { 412 int slen; 413 struct SL_component *slp; 414 struct SL_component *oldslp; 415 slen = rr->len - 5; 416 slp = &rr->u.SL.link; 417 inode->i_size = symlink_len; 418 while (slen > 1) { 419 rootflag = 0; 420 switch (slp->flags & ~1) { 421 case 0: 422 inode->i_size += 423 slp->len; 424 break; 425 case 2: 426 inode->i_size += 1; 427 break; 428 case 4: 429 inode->i_size += 2; 430 break; 431 case 8: 432 rootflag = 1; 433 inode->i_size += 1; 434 break; 435 default: 436 printk("Symlink component flag " 437 "not implemented\n"); 438 } 439 slen -= slp->len + 2; 440 oldslp = slp; 441 slp = (struct SL_component *) 442 (((char *)slp) + slp->len + 2); 443 444 if (slen < 2) { 445 if (((rr->u.SL. 446 flags & 1) != 0) 447 && 448 ((oldslp-> 449 flags & 1) == 0)) 450 inode->i_size += 451 1; 452 break; 453 } 454 455 /* 456 * If this component record isn't 457 * continued, then append a '/'. 458 */ 459 if (!rootflag 460 && (oldslp->flags & 1) == 0) 461 inode->i_size += 1; 462 } 463 } 464 symlink_len = inode->i_size; 465 break; 466 case SIG('R', 'E'): 467 printk(KERN_WARNING "Attempt to read inode for " 468 "relocated directory\n"); 469 goto out; 470 case SIG('C', 'L'): 471 ISOFS_I(inode)->i_first_extent = 472 isonum_733(rr->u.CL.location); 473 reloc = 474 isofs_iget(inode->i_sb, 475 ISOFS_I(inode)->i_first_extent, 476 0); 477 if (!reloc) 478 goto out; 479 inode->i_mode = reloc->i_mode; 480 inode->i_nlink = reloc->i_nlink; 481 inode->i_uid = reloc->i_uid; 482 inode->i_gid = reloc->i_gid; 483 inode->i_rdev = reloc->i_rdev; 484 inode->i_size = reloc->i_size; 485 inode->i_blocks = reloc->i_blocks; 486 inode->i_atime = reloc->i_atime; 487 inode->i_ctime = reloc->i_ctime; 488 inode->i_mtime = reloc->i_mtime; 489 iput(reloc); 490 break; 491#ifdef CONFIG_ZISOFS 492 case SIG('Z', 'F'): { 493 int algo; 494 495 if (ISOFS_SB(inode->i_sb)->s_nocompress) 496 break; 497 algo = isonum_721(rr->u.ZF.algorithm); 498 if (algo == SIG('p', 'z')) { 499 int block_shift = 500 isonum_711(&rr->u.ZF.parms[1]); 501 if (block_shift < PAGE_CACHE_SHIFT 502 || block_shift > 17) { 503 printk(KERN_WARNING "isofs: " 504 "Can't handle ZF block " 505 "size of 2^%d\n", 506 block_shift); 507 } else { 508 /* 509 * Note: we don't change 510 * i_blocks here 511 */ 512 ISOFS_I(inode)->i_file_format = 513 isofs_file_compressed; 514 /* 515 * Parameters to compression 516 * algorithm (header size, 517 * block size) 518 */ 519 ISOFS_I(inode)->i_format_parm[0] = 520 isonum_711(&rr->u.ZF.parms[0]); 521 ISOFS_I(inode)->i_format_parm[1] = 522 isonum_711(&rr->u.ZF.parms[1]); 523 inode->i_size = 524 isonum_733(rr->u.ZF. 525 real_size); 526 } 527 } else { 528 printk(KERN_WARNING 529 "isofs: Unknown ZF compression " 530 "algorithm: %c%c\n", 531 rr->u.ZF.algorithm[0], 532 rr->u.ZF.algorithm[1]); 533 } 534 break; 535 } 536#endif 537 default: 538 break; 539 } 540 } 541 ret = rock_continue(&rs); 542 if (ret == 0) 543 goto repeat; 544 if (ret == 1) 545 ret = 0; 546out: 547 kfree(rs.buffer); 548 return ret; 549eio: 550 ret = -EIO; 551 goto out; 552} 553 554static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit) 555{ 556 int slen; 557 int rootflag; 558 struct SL_component *oldslp; 559 struct SL_component *slp; 560 slen = rr->len - 5; 561 slp = &rr->u.SL.link; 562 while (slen > 1) { 563 rootflag = 0; 564 switch (slp->flags & ~1) { 565 case 0: 566 if (slp->len > plimit - rpnt) 567 return NULL; 568 memcpy(rpnt, slp->text, slp->len); 569 rpnt += slp->len; 570 break; 571 case 2: 572 if (rpnt >= plimit) 573 return NULL; 574 *rpnt++ = '.'; 575 break; 576 case 4: 577 if (2 > plimit - rpnt) 578 return NULL; 579 *rpnt++ = '.'; 580 *rpnt++ = '.'; 581 break; 582 case 8: 583 if (rpnt >= plimit) 584 return NULL; 585 rootflag = 1; 586 *rpnt++ = '/'; 587 break; 588 default: 589 printk("Symlink component flag not implemented (%d)\n", 590 slp->flags); 591 } 592 slen -= slp->len + 2; 593 oldslp = slp; 594 slp = (struct SL_component *)((char *)slp + slp->len + 2); 595 596 if (slen < 2) { 597 /* 598 * If there is another SL record, and this component 599 * record isn't continued, then add a slash. 600 */ 601 if ((!rootflag) && (rr->u.SL.flags & 1) && 602 !(oldslp->flags & 1)) { 603 if (rpnt >= plimit) 604 return NULL; 605 *rpnt++ = '/'; 606 } 607 break; 608 } 609 610 /* 611 * If this component record isn't continued, then append a '/'. 612 */ 613 if (!rootflag && !(oldslp->flags & 1)) { 614 if (rpnt >= plimit) 615 return NULL; 616 *rpnt++ = '/'; 617 } 618 } 619 return rpnt; 620} 621 622int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode) 623{ 624 int result = parse_rock_ridge_inode_internal(de, inode, 0); 625 626 /* 627 * if rockridge flag was reset and we didn't look for attributes 628 * behind eventual XA attributes, have a look there 629 */ 630 if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1) 631 && (ISOFS_SB(inode->i_sb)->s_rock == 2)) { 632 result = parse_rock_ridge_inode_internal(de, inode, 14); 633 } 634 return result; 635} 636 637/* 638 * readpage() for symlinks: reads symlink contents into the page and either 639 * makes it uptodate and returns 0 or returns error (-EIO) 640 */ 641static int rock_ridge_symlink_readpage(struct file *file, struct page *page) 642{ 643 struct inode *inode = page->mapping->host; 644 struct iso_inode_info *ei = ISOFS_I(inode); 645 char *link = kmap(page); 646 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode); 647 struct buffer_head *bh; 648 char *rpnt = link; 649 unsigned char *pnt; 650 struct iso_directory_record *raw_de; 651 unsigned long block, offset; 652 int sig; 653 struct rock_ridge *rr; 654 struct rock_state rs; 655 int ret; 656 657 if (!ISOFS_SB(inode->i_sb)->s_rock) 658 goto error; 659 660 init_rock_state(&rs, inode); 661 block = ei->i_iget5_block; 662 lock_kernel(); 663 bh = sb_bread(inode->i_sb, block); 664 if (!bh) 665 goto out_noread; 666 667 offset = ei->i_iget5_offset; 668 pnt = (unsigned char *)bh->b_data + offset; 669 670 raw_de = (struct iso_directory_record *)pnt; 671 672 /* 673 * If we go past the end of the buffer, there is some sort of error. 674 */ 675 if (offset + *pnt > bufsize) 676 goto out_bad_span; 677 678 /* 679 * Now test for possible Rock Ridge extensions which will override 680 * some of these numbers in the inode structure. 681 */ 682 683 setup_rock_ridge(raw_de, inode, &rs); 684 685repeat: 686 while (rs.len > 2) { /* There may be one byte for padding somewhere */ 687 rr = (struct rock_ridge *)rs.chr; 688 if (rr->len < 3) 689 goto out; /* Something got screwed up here */ 690 sig = isonum_721(rs.chr); 691 if (rock_check_overflow(&rs, sig)) 692 goto out; 693 rs.chr += rr->len; 694 rs.len -= rr->len; 695 if (rs.len < 0) 696 goto out; /* corrupted isofs */ 697 698 switch (sig) { 699 case SIG('R', 'R'): 700 if ((rr->u.RR.flags[0] & RR_SL) == 0) 701 goto out; 702 break; 703 case SIG('S', 'P'): 704 if (check_sp(rr, inode)) 705 goto out; 706 break; 707 case SIG('S', 'L'): 708 rpnt = get_symlink_chunk(rpnt, rr, 709 link + (PAGE_SIZE - 1)); 710 if (rpnt == NULL) 711 goto out; 712 break; 713 case SIG('C', 'E'): 714 /* This tells is if there is a continuation record */ 715 rs.cont_extent = isonum_733(rr->u.CE.extent); 716 rs.cont_offset = isonum_733(rr->u.CE.offset); 717 rs.cont_size = isonum_733(rr->u.CE.size); 718 default: 719 break; 720 } 721 } 722 ret = rock_continue(&rs); 723 if (ret == 0) 724 goto repeat; 725 if (ret < 0) 726 goto fail; 727 728 if (rpnt == link) 729 goto fail; 730 brelse(bh); 731 *rpnt = '\0'; 732 unlock_kernel(); 733 SetPageUptodate(page); 734 kunmap(page); 735 unlock_page(page); 736 return 0; 737 738 /* error exit from macro */ 739out: 740 kfree(rs.buffer); 741 goto fail; 742out_noread: 743 printk("unable to read i-node block"); 744 goto fail; 745out_bad_span: 746 printk("symlink spans iso9660 blocks\n"); 747fail: 748 brelse(bh); 749 unlock_kernel(); 750error: 751 SetPageError(page); 752 kunmap(page); 753 unlock_page(page); 754 return -EIO; 755} 756 757const struct address_space_operations isofs_symlink_aops = { 758 .readpage = rock_ridge_symlink_readpage 759}; 760