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 27 struct 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 42 static 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 52 static 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 71 static 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 */ 81 static 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 } 123 out: 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 */ 133 static 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 */ 192 int 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); 208 repeat: 209 210 while (rs.len > 2) { /* There may be one byte for padding somewhere */ 211 rr = (struct rock_ridge *)rs.chr; 212 /* 213 * Ignore rock ridge info if rr->len is out of range, but 214 * don't return -EIO because that would make the file 215 * invisible. 216 */ 217 if (rr->len < 3) 218 goto out; /* Something got screwed up here */ 219 sig = isonum_721(rs.chr); 220 if (rock_check_overflow(&rs, sig)) 221 goto eio; 222 rs.chr += rr->len; 223 rs.len -= rr->len; 224 /* 225 * As above, just ignore the rock ridge info if rr->len 226 * is bogus. 227 */ 228 if (rs.len < 0) 229 goto out; /* Something got screwed up here */ 230 231 switch (sig) { 232 case SIG('R', 'R'): 233 if ((rr->u.RR.flags[0] & RR_NM) == 0) 234 goto out; 235 break; 236 case SIG('S', 'P'): 237 if (check_sp(rr, inode)) 238 goto out; 239 break; 240 case SIG('C', 'E'): 241 rs.cont_extent = isonum_733(rr->u.CE.extent); 242 rs.cont_offset = isonum_733(rr->u.CE.offset); 243 rs.cont_size = isonum_733(rr->u.CE.size); 244 break; 245 case SIG('N', 'M'): 246 if (truncate) 247 break; 248 if (rr->len < 5) 249 break; 250 /* 251 * If the flags are 2 or 4, this indicates '.' or '..'. 252 * We don't want to do anything with this, because it 253 * screws up the code that calls us. We don't really 254 * care anyways, since we can just use the non-RR 255 * name. 256 */ 257 if (rr->u.NM.flags & 6) 258 break; 259 260 if (rr->u.NM.flags & ~1) { 261 printk("Unsupported NM flag settings (%d)\n", 262 rr->u.NM.flags); 263 break; 264 } 265 if ((strlen(retname) + rr->len - 5) >= 254) { 266 truncate = 1; 267 break; 268 } 269 strncat(retname, rr->u.NM.name, rr->len - 5); 270 retnamlen += rr->len - 5; 271 break; 272 case SIG('R', 'E'): 273 kfree(rs.buffer); 274 return -1; 275 default: 276 break; 277 } 278 } 279 ret = rock_continue(&rs); 280 if (ret == 0) 281 goto repeat; 282 if (ret == 1) 283 return retnamlen; /* If 0, this file did not have a NM field */ 284 out: 285 kfree(rs.buffer); 286 return ret; 287 eio: 288 ret = -EIO; 289 goto out; 290 } 291 292 static int 293 parse_rock_ridge_inode_internal(struct iso_directory_record *de, 294 struct inode *inode, int regard_xa) 295 { 296 int symlink_len = 0; 297 int cnt, sig; 298 struct inode *reloc; 299 struct rock_ridge *rr; 300 int rootflag; 301 struct rock_state rs; 302 int ret = 0; 303 304 if (!ISOFS_SB(inode->i_sb)->s_rock) 305 return 0; 306 307 init_rock_state(&rs, inode); 308 setup_rock_ridge(de, inode, &rs); 309 if (regard_xa) { 310 rs.chr += 14; 311 rs.len -= 14; 312 if (rs.len < 0) 313 rs.len = 0; 314 } 315 316 repeat: 317 while (rs.len > 2) { /* There may be one byte for padding somewhere */ 318 rr = (struct rock_ridge *)rs.chr; 319 /* 320 * Ignore rock ridge info if rr->len is out of range, but 321 * don't return -EIO because that would make the file 322 * invisible. 323 */ 324 if (rr->len < 3) 325 goto out; /* Something got screwed up here */ 326 sig = isonum_721(rs.chr); 327 if (rock_check_overflow(&rs, sig)) 328 goto eio; 329 rs.chr += rr->len; 330 rs.len -= rr->len; 331 /* 332 * As above, just ignore the rock ridge info if rr->len 333 * is bogus. 334 */ 335 if (rs.len < 0) 336 goto out; /* Something got screwed up here */ 337 338 switch (sig) { 339 #ifndef CONFIG_ZISOFS /* No flag for SF or ZF */ 340 case SIG('R', 'R'): 341 if ((rr->u.RR.flags[0] & 342 (RR_PX | RR_TF | RR_SL | RR_CL)) == 0) 343 goto out; 344 break; 345 #endif 346 case SIG('S', 'P'): 347 if (check_sp(rr, inode)) 348 goto out; 349 break; 350 case SIG('C', 'E'): 351 rs.cont_extent = isonum_733(rr->u.CE.extent); 352 rs.cont_offset = isonum_733(rr->u.CE.offset); 353 rs.cont_size = isonum_733(rr->u.CE.size); 354 break; 355 case SIG('E', 'R'): 356 ISOFS_SB(inode->i_sb)->s_rock = 1; 357 printk(KERN_DEBUG "ISO 9660 Extensions: "); 358 { 359 int p; 360 for (p = 0; p < rr->u.ER.len_id; p++) 361 printk("%c", rr->u.ER.data[p]); 362 } 363 printk("\n"); 364 break; 365 case SIG('P', 'X'): 366 inode->i_mode = isonum_733(rr->u.PX.mode); 367 inode->i_nlink = isonum_733(rr->u.PX.n_links); 368 inode->i_uid = isonum_733(rr->u.PX.uid); 369 inode->i_gid = isonum_733(rr->u.PX.gid); 370 break; 371 case SIG('P', 'N'): 372 { 373 int high, low; 374 high = isonum_733(rr->u.PN.dev_high); 375 low = isonum_733(rr->u.PN.dev_low); 376 /* 377 * The Rock Ridge standard specifies that if 378 * sizeof(dev_t) <= 4, then the high field is 379 * unused, and the device number is completely 380 * stored in the low field. Some writers may 381 * ignore this subtlety, 382 * and as a result we test to see if the entire 383 * device number is 384 * stored in the low field, and use that. 385 */ 386 if ((low & ~0xff) && high == 0) { 387 inode->i_rdev = 388 MKDEV(low >> 8, low & 0xff); 389 } else { 390 inode->i_rdev = 391 MKDEV(high, low); 392 } 393 } 394 break; 395 case SIG('T', 'F'): 396 /* 397 * Some RRIP writers incorrectly place ctime in the 398 * TF_CREATE field. Try to handle this correctly for 399 * either case. 400 */ 401 /* Rock ridge never appears on a High Sierra disk */ 402 cnt = 0; 403 if (rr->u.TF.flags & TF_CREATE) { 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 if (rr->u.TF.flags & TF_MODIFY) { 410 inode->i_mtime.tv_sec = 411 iso_date(rr->u.TF.times[cnt++].time, 412 0); 413 inode->i_mtime.tv_nsec = 0; 414 } 415 if (rr->u.TF.flags & TF_ACCESS) { 416 inode->i_atime.tv_sec = 417 iso_date(rr->u.TF.times[cnt++].time, 418 0); 419 inode->i_atime.tv_nsec = 0; 420 } 421 if (rr->u.TF.flags & TF_ATTRIBUTES) { 422 inode->i_ctime.tv_sec = 423 iso_date(rr->u.TF.times[cnt++].time, 424 0); 425 inode->i_ctime.tv_nsec = 0; 426 } 427 break; 428 case SIG('S', 'L'): 429 { 430 int slen; 431 struct SL_component *slp; 432 struct SL_component *oldslp; 433 slen = rr->len - 5; 434 slp = &rr->u.SL.link; 435 inode->i_size = symlink_len; 436 while (slen > 1) { 437 rootflag = 0; 438 switch (slp->flags & ~1) { 439 case 0: 440 inode->i_size += 441 slp->len; 442 break; 443 case 2: 444 inode->i_size += 1; 445 break; 446 case 4: 447 inode->i_size += 2; 448 break; 449 case 8: 450 rootflag = 1; 451 inode->i_size += 1; 452 break; 453 default: 454 printk("Symlink component flag " 455 "not implemented\n"); 456 } 457 slen -= slp->len + 2; 458 oldslp = slp; 459 slp = (struct SL_component *) 460 (((char *)slp) + slp->len + 2); 461 462 if (slen < 2) { 463 if (((rr->u.SL. 464 flags & 1) != 0) 465 && 466 ((oldslp-> 467 flags & 1) == 0)) 468 inode->i_size += 469 1; 470 break; 471 } 472 473 /* 474 * If this component record isn't 475 * continued, then append a '/'. 476 */ 477 if (!rootflag 478 && (oldslp->flags & 1) == 0) 479 inode->i_size += 1; 480 } 481 } 482 symlink_len = inode->i_size; 483 break; 484 case SIG('R', 'E'): 485 printk(KERN_WARNING "Attempt to read inode for " 486 "relocated directory\n"); 487 goto out; 488 case SIG('C', 'L'): 489 ISOFS_I(inode)->i_first_extent = 490 isonum_733(rr->u.CL.location); 491 reloc = 492 isofs_iget(inode->i_sb, 493 ISOFS_I(inode)->i_first_extent, 494 0); 495 if (IS_ERR(reloc)) { 496 ret = PTR_ERR(reloc); 497 goto out; 498 } 499 inode->i_mode = reloc->i_mode; 500 inode->i_nlink = reloc->i_nlink; 501 inode->i_uid = reloc->i_uid; 502 inode->i_gid = reloc->i_gid; 503 inode->i_rdev = reloc->i_rdev; 504 inode->i_size = reloc->i_size; 505 inode->i_blocks = reloc->i_blocks; 506 inode->i_atime = reloc->i_atime; 507 inode->i_ctime = reloc->i_ctime; 508 inode->i_mtime = reloc->i_mtime; 509 iput(reloc); 510 break; 511 #ifdef CONFIG_ZISOFS 512 case SIG('Z', 'F'): { 513 int algo; 514 515 if (ISOFS_SB(inode->i_sb)->s_nocompress) 516 break; 517 algo = isonum_721(rr->u.ZF.algorithm); 518 if (algo == SIG('p', 'z')) { 519 int block_shift = 520 isonum_711(&rr->u.ZF.parms[1]); 521 if (block_shift > 17) { 522 printk(KERN_WARNING "isofs: " 523 "Can't handle ZF block " 524 "size of 2^%d\n", 525 block_shift); 526 } else { 527 /* 528 * Note: we don't change 529 * i_blocks here 530 */ 531 ISOFS_I(inode)->i_file_format = 532 isofs_file_compressed; 533 /* 534 * Parameters to compression 535 * algorithm (header size, 536 * block size) 537 */ 538 ISOFS_I(inode)->i_format_parm[0] = 539 isonum_711(&rr->u.ZF.parms[0]); 540 ISOFS_I(inode)->i_format_parm[1] = 541 isonum_711(&rr->u.ZF.parms[1]); 542 inode->i_size = 543 isonum_733(rr->u.ZF. 544 real_size); 545 } 546 } else { 547 printk(KERN_WARNING 548 "isofs: Unknown ZF compression " 549 "algorithm: %c%c\n", 550 rr->u.ZF.algorithm[0], 551 rr->u.ZF.algorithm[1]); 552 } 553 break; 554 } 555 #endif 556 default: 557 break; 558 } 559 } 560 ret = rock_continue(&rs); 561 if (ret == 0) 562 goto repeat; 563 if (ret == 1) 564 ret = 0; 565 out: 566 kfree(rs.buffer); 567 return ret; 568 eio: 569 ret = -EIO; 570 goto out; 571 } 572 573 static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit) 574 { 575 int slen; 576 int rootflag; 577 struct SL_component *oldslp; 578 struct SL_component *slp; 579 slen = rr->len - 5; 580 slp = &rr->u.SL.link; 581 while (slen > 1) { 582 rootflag = 0; 583 switch (slp->flags & ~1) { 584 case 0: 585 if (slp->len > plimit - rpnt) 586 return NULL; 587 memcpy(rpnt, slp->text, slp->len); 588 rpnt += slp->len; 589 break; 590 case 2: 591 if (rpnt >= plimit) 592 return NULL; 593 *rpnt++ = '.'; 594 break; 595 case 4: 596 if (2 > plimit - rpnt) 597 return NULL; 598 *rpnt++ = '.'; 599 *rpnt++ = '.'; 600 break; 601 case 8: 602 if (rpnt >= plimit) 603 return NULL; 604 rootflag = 1; 605 *rpnt++ = '/'; 606 break; 607 default: 608 printk("Symlink component flag not implemented (%d)\n", 609 slp->flags); 610 } 611 slen -= slp->len + 2; 612 oldslp = slp; 613 slp = (struct SL_component *)((char *)slp + slp->len + 2); 614 615 if (slen < 2) { 616 /* 617 * If there is another SL record, and this component 618 * record isn't continued, then add a slash. 619 */ 620 if ((!rootflag) && (rr->u.SL.flags & 1) && 621 !(oldslp->flags & 1)) { 622 if (rpnt >= plimit) 623 return NULL; 624 *rpnt++ = '/'; 625 } 626 break; 627 } 628 629 /* 630 * If this component record isn't continued, then append a '/'. 631 */ 632 if (!rootflag && !(oldslp->flags & 1)) { 633 if (rpnt >= plimit) 634 return NULL; 635 *rpnt++ = '/'; 636 } 637 } 638 return rpnt; 639 } 640 641 int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode) 642 { 643 int result = parse_rock_ridge_inode_internal(de, inode, 0); 644 645 /* 646 * if rockridge flag was reset and we didn't look for attributes 647 * behind eventual XA attributes, have a look there 648 */ 649 if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1) 650 && (ISOFS_SB(inode->i_sb)->s_rock == 2)) { 651 result = parse_rock_ridge_inode_internal(de, inode, 14); 652 } 653 return result; 654 } 655 656 /* 657 * readpage() for symlinks: reads symlink contents into the page and either 658 * makes it uptodate and returns 0 or returns error (-EIO) 659 */ 660 static int rock_ridge_symlink_readpage(struct file *file, struct page *page) 661 { 662 struct inode *inode = page->mapping->host; 663 struct iso_inode_info *ei = ISOFS_I(inode); 664 char *link = kmap(page); 665 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode); 666 struct buffer_head *bh; 667 char *rpnt = link; 668 unsigned char *pnt; 669 struct iso_directory_record *raw_de; 670 unsigned long block, offset; 671 int sig; 672 struct rock_ridge *rr; 673 struct rock_state rs; 674 int ret; 675 676 if (!ISOFS_SB(inode->i_sb)->s_rock) 677 goto error; 678 679 init_rock_state(&rs, inode); 680 block = ei->i_iget5_block; 681 lock_kernel(); 682 bh = sb_bread(inode->i_sb, block); 683 if (!bh) 684 goto out_noread; 685 686 offset = ei->i_iget5_offset; 687 pnt = (unsigned char *)bh->b_data + offset; 688 689 raw_de = (struct iso_directory_record *)pnt; 690 691 /* 692 * If we go past the end of the buffer, there is some sort of error. 693 */ 694 if (offset + *pnt > bufsize) 695 goto out_bad_span; 696 697 /* 698 * Now test for possible Rock Ridge extensions which will override 699 * some of these numbers in the inode structure. 700 */ 701 702 setup_rock_ridge(raw_de, inode, &rs); 703 704 repeat: 705 while (rs.len > 2) { /* There may be one byte for padding somewhere */ 706 rr = (struct rock_ridge *)rs.chr; 707 if (rr->len < 3) 708 goto out; /* Something got screwed up here */ 709 sig = isonum_721(rs.chr); 710 if (rock_check_overflow(&rs, sig)) 711 goto out; 712 rs.chr += rr->len; 713 rs.len -= rr->len; 714 if (rs.len < 0) 715 goto out; /* corrupted isofs */ 716 717 switch (sig) { 718 case SIG('R', 'R'): 719 if ((rr->u.RR.flags[0] & RR_SL) == 0) 720 goto out; 721 break; 722 case SIG('S', 'P'): 723 if (check_sp(rr, inode)) 724 goto out; 725 break; 726 case SIG('S', 'L'): 727 rpnt = get_symlink_chunk(rpnt, rr, 728 link + (PAGE_SIZE - 1)); 729 if (rpnt == NULL) 730 goto out; 731 break; 732 case SIG('C', 'E'): 733 /* This tells is if there is a continuation record */ 734 rs.cont_extent = isonum_733(rr->u.CE.extent); 735 rs.cont_offset = isonum_733(rr->u.CE.offset); 736 rs.cont_size = isonum_733(rr->u.CE.size); 737 default: 738 break; 739 } 740 } 741 ret = rock_continue(&rs); 742 if (ret == 0) 743 goto repeat; 744 if (ret < 0) 745 goto fail; 746 747 if (rpnt == link) 748 goto fail; 749 brelse(bh); 750 *rpnt = '\0'; 751 unlock_kernel(); 752 SetPageUptodate(page); 753 kunmap(page); 754 unlock_page(page); 755 return 0; 756 757 /* error exit from macro */ 758 out: 759 kfree(rs.buffer); 760 goto fail; 761 out_noread: 762 printk("unable to read i-node block"); 763 goto fail; 764 out_bad_span: 765 printk("symlink spans iso9660 blocks\n"); 766 fail: 767 brelse(bh); 768 unlock_kernel(); 769 error: 770 SetPageError(page); 771 kunmap(page); 772 unlock_page(page); 773 return -EIO; 774 } 775 776 const struct address_space_operations isofs_symlink_aops = { 777 .readpage = rock_ridge_symlink_readpage 778 }; 779