1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/isofs/rock.c
4 *
5 * (C) 1992, 1993 Eric Youngdale
6 *
7 * Rock Ridge Extensions to iso9660
8 */
9
10 #include <linux/slab.h>
11 #include <linux/pagemap.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 int cont_loops;
35 struct inode *inode;
36 };
37
38 /*
39 * This is a way of ensuring that we have something in the system
40 * use fields that is compatible with Rock Ridge. Return zero on success.
41 */
42
check_sp(struct rock_ridge * rr,struct inode * inode)43 static int check_sp(struct rock_ridge *rr, struct inode *inode)
44 {
45 if (rr->u.SP.magic[0] != 0xbe)
46 return -1;
47 if (rr->u.SP.magic[1] != 0xef)
48 return -1;
49 ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip;
50 return 0;
51 }
52
setup_rock_ridge(struct iso_directory_record * de,struct inode * inode,struct rock_state * rs)53 static void setup_rock_ridge(struct iso_directory_record *de,
54 struct inode *inode, struct rock_state *rs)
55 {
56 rs->len = sizeof(struct iso_directory_record) + de->name_len[0];
57 if (rs->len & 1)
58 (rs->len)++;
59 rs->chr = (unsigned char *)de + rs->len;
60 rs->len = *((unsigned char *)de) - rs->len;
61 if (rs->len < 0)
62 rs->len = 0;
63
64 if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) {
65 rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset;
66 rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset;
67 if (rs->len < 0)
68 rs->len = 0;
69 }
70 }
71
init_rock_state(struct rock_state * rs,struct inode * inode)72 static void init_rock_state(struct rock_state *rs, struct inode *inode)
73 {
74 memset(rs, 0, sizeof(*rs));
75 rs->inode = inode;
76 }
77
78 /* Maximum number of Rock Ridge continuation entries */
79 #define RR_MAX_CE_ENTRIES 32
80
81 /*
82 * Returns 0 if the caller should continue scanning, 1 if the scan must end
83 * and -ve on error.
84 */
rock_continue(struct rock_state * rs)85 static int rock_continue(struct rock_state *rs)
86 {
87 int ret = 1;
88 int blocksize = 1 << rs->inode->i_blkbits;
89 const int min_de_size = offsetof(struct rock_ridge, u);
90
91 kfree(rs->buffer);
92 rs->buffer = NULL;
93
94 if ((unsigned)rs->cont_offset > blocksize - min_de_size ||
95 (unsigned)rs->cont_size > blocksize ||
96 (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) {
97 printk(KERN_NOTICE "rock: corrupted directory entry. "
98 "extent=%d, offset=%d, size=%d\n",
99 rs->cont_extent, rs->cont_offset, rs->cont_size);
100 ret = -EIO;
101 goto out;
102 }
103
104 if ((unsigned)rs->cont_extent >= ISOFS_SB(rs->inode->i_sb)->s_nzones) {
105 printk(KERN_NOTICE "rock: corrupted directory entry. "
106 "extent=%u out of volume (nzones=%lu)\n",
107 (unsigned)rs->cont_extent,
108 ISOFS_SB(rs->inode->i_sb)->s_nzones);
109 ret = -EIO;
110 goto out;
111 }
112
113 if (rs->cont_extent) {
114 struct buffer_head *bh;
115
116 rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL);
117 if (!rs->buffer) {
118 ret = -ENOMEM;
119 goto out;
120 }
121 ret = -EIO;
122 if (++rs->cont_loops >= RR_MAX_CE_ENTRIES)
123 goto out;
124 bh = sb_bread(rs->inode->i_sb, rs->cont_extent);
125 if (bh) {
126 memcpy(rs->buffer, bh->b_data + rs->cont_offset,
127 rs->cont_size);
128 put_bh(bh);
129 rs->chr = rs->buffer;
130 rs->len = rs->cont_size;
131 rs->cont_extent = 0;
132 rs->cont_size = 0;
133 rs->cont_offset = 0;
134 return 0;
135 }
136 printk("Unable to read rock-ridge attributes\n");
137 }
138 out:
139 kfree(rs->buffer);
140 rs->buffer = NULL;
141 return ret;
142 }
143
144 /*
145 * We think there's a record of type `sig' at rs->chr. Parse the signature
146 * and make sure that there's really room for a record of that type.
147 */
rock_check_overflow(struct rock_state * rs,int sig)148 static int rock_check_overflow(struct rock_state *rs, int sig)
149 {
150 int len;
151
152 switch (sig) {
153 case SIG('S', 'P'):
154 len = sizeof(struct SU_SP_s);
155 break;
156 case SIG('C', 'E'):
157 len = sizeof(struct SU_CE_s);
158 break;
159 case SIG('E', 'R'):
160 len = sizeof(struct SU_ER_s);
161 break;
162 case SIG('R', 'R'):
163 len = sizeof(struct RR_RR_s);
164 break;
165 case SIG('P', 'X'):
166 len = sizeof(struct RR_PX_s);
167 break;
168 case SIG('P', 'N'):
169 len = sizeof(struct RR_PN_s);
170 break;
171 case SIG('S', 'L'):
172 len = sizeof(struct RR_SL_s);
173 break;
174 case SIG('N', 'M'):
175 len = sizeof(struct RR_NM_s);
176 break;
177 case SIG('C', 'L'):
178 len = sizeof(struct RR_CL_s);
179 break;
180 case SIG('P', 'L'):
181 len = sizeof(struct RR_PL_s);
182 break;
183 case SIG('T', 'F'):
184 len = sizeof(struct RR_TF_s);
185 break;
186 case SIG('Z', 'F'):
187 len = sizeof(struct RR_ZF_s);
188 break;
189 default:
190 len = 0;
191 break;
192 }
193 len += offsetof(struct rock_ridge, u);
194 if (len > rs->len) {
195 printk(KERN_NOTICE "rock: directory entry would overflow "
196 "storage\n");
197 printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n",
198 sig, len, rs->len);
199 return -EIO;
200 }
201 return 0;
202 }
203
204 /*
205 * return length of name field; 0: not found, -1: to be ignored
206 */
get_rock_ridge_filename(struct iso_directory_record * de,char * retname,struct inode * inode)207 int get_rock_ridge_filename(struct iso_directory_record *de,
208 char *retname, struct inode *inode)
209 {
210 struct rock_state rs;
211 struct rock_ridge *rr;
212 int sig;
213 int retnamlen = 0;
214 int truncate = 0;
215 int ret = 0;
216 char *p;
217 int len;
218
219 if (!ISOFS_SB(inode->i_sb)->s_rock)
220 return 0;
221 *retname = 0;
222
223 init_rock_state(&rs, inode);
224 setup_rock_ridge(de, inode, &rs);
225 repeat:
226
227 while (rs.len > 2) { /* There may be one byte for padding somewhere */
228 rr = (struct rock_ridge *)rs.chr;
229 /*
230 * Ignore rock ridge info if rr->len is out of range, but
231 * don't return -EIO because that would make the file
232 * invisible.
233 */
234 if (rr->len < 3)
235 goto out; /* Something got screwed up here */
236 sig = isonum_721(rs.chr);
237 if (rock_check_overflow(&rs, sig))
238 goto eio;
239 rs.chr += rr->len;
240 rs.len -= rr->len;
241 /*
242 * As above, just ignore the rock ridge info if rr->len
243 * is bogus.
244 */
245 if (rs.len < 0)
246 goto out; /* Something got screwed up here */
247
248 switch (sig) {
249 case SIG('R', 'R'):
250 if ((rr->u.RR.flags[0] & RR_NM) == 0)
251 goto out;
252 break;
253 case SIG('S', 'P'):
254 if (check_sp(rr, inode))
255 goto out;
256 break;
257 case SIG('C', 'E'):
258 rs.cont_extent = isonum_733(rr->u.CE.extent);
259 rs.cont_offset = isonum_733(rr->u.CE.offset);
260 rs.cont_size = isonum_733(rr->u.CE.size);
261 break;
262 case SIG('N', 'M'):
263 if (truncate)
264 break;
265 if (rr->len < 5)
266 break;
267 /*
268 * If the flags are 2 or 4, this indicates '.' or '..'.
269 * We don't want to do anything with this, because it
270 * screws up the code that calls us. We don't really
271 * care anyways, since we can just use the non-RR
272 * name.
273 */
274 if (rr->u.NM.flags & 6)
275 break;
276
277 if (rr->u.NM.flags & ~1) {
278 printk("Unsupported NM flag settings (%d)\n",
279 rr->u.NM.flags);
280 break;
281 }
282 len = rr->len - 5;
283 if (retnamlen + len > NAME_MAX) {
284 truncate = 1;
285 break;
286 }
287 p = memchr(rr->u.NM.name, '\0', len);
288 if (unlikely(p))
289 len = p - rr->u.NM.name;
290 memcpy(retname + retnamlen, rr->u.NM.name, len);
291 retnamlen += len;
292 retname[retnamlen] = '\0';
293 break;
294 case SIG('R', 'E'):
295 kfree(rs.buffer);
296 return -1;
297 default:
298 break;
299 }
300 }
301 ret = rock_continue(&rs);
302 if (ret == 0)
303 goto repeat;
304 if (ret == 1)
305 return retnamlen; /* If 0, this file did not have a NM field */
306 out:
307 kfree(rs.buffer);
308 return ret;
309 eio:
310 ret = -EIO;
311 goto out;
312 }
313
314 #define RR_REGARD_XA 1
315 #define RR_RELOC_DE 2
316
317 static int
parse_rock_ridge_inode_internal(struct iso_directory_record * de,struct inode * inode,int flags)318 parse_rock_ridge_inode_internal(struct iso_directory_record *de,
319 struct inode *inode, int flags)
320 {
321 int symlink_len = 0;
322 int cnt, sig;
323 unsigned int reloc_block;
324 struct inode *reloc;
325 struct rock_ridge *rr;
326 int rootflag;
327 struct rock_state rs;
328 int ret = 0;
329
330 if (!ISOFS_SB(inode->i_sb)->s_rock)
331 return 0;
332
333 init_rock_state(&rs, inode);
334 setup_rock_ridge(de, inode, &rs);
335 if (flags & RR_REGARD_XA) {
336 rs.chr += 14;
337 rs.len -= 14;
338 if (rs.len < 0)
339 rs.len = 0;
340 }
341
342 repeat:
343 while (rs.len > 2) { /* There may be one byte for padding somewhere */
344 rr = (struct rock_ridge *)rs.chr;
345 /*
346 * Ignore rock ridge info if rr->len is out of range, but
347 * don't return -EIO because that would make the file
348 * invisible.
349 */
350 if (rr->len < 3)
351 goto out; /* Something got screwed up here */
352 sig = isonum_721(rs.chr);
353 if (rock_check_overflow(&rs, sig))
354 goto eio;
355 rs.chr += rr->len;
356 rs.len -= rr->len;
357 /*
358 * As above, just ignore the rock ridge info if rr->len
359 * is bogus.
360 */
361 if (rs.len < 0)
362 goto out; /* Something got screwed up here */
363
364 switch (sig) {
365 #ifndef CONFIG_ZISOFS /* No flag for SF or ZF */
366 case SIG('R', 'R'):
367 if ((rr->u.RR.flags[0] &
368 (RR_PX | RR_TF | RR_SL | RR_CL)) == 0)
369 goto out;
370 break;
371 #endif
372 case SIG('S', 'P'):
373 if (check_sp(rr, inode))
374 goto out;
375 break;
376 case SIG('C', 'E'):
377 rs.cont_extent = isonum_733(rr->u.CE.extent);
378 rs.cont_offset = isonum_733(rr->u.CE.offset);
379 rs.cont_size = isonum_733(rr->u.CE.size);
380 break;
381 case SIG('E', 'R'):
382 /* Invalid length of ER tag id? */
383 if (rr->u.ER.len_id + offsetof(struct rock_ridge, u.ER.data) > rr->len)
384 goto out;
385 ISOFS_SB(inode->i_sb)->s_rock = 1;
386 printk(KERN_DEBUG "ISO 9660 Extensions: ");
387 {
388 int p;
389 for (p = 0; p < rr->u.ER.len_id; p++)
390 printk(KERN_CONT "%c", rr->u.ER.data[p]);
391 }
392 printk(KERN_CONT "\n");
393 break;
394 case SIG('P', 'X'):
395 inode->i_mode = isonum_733(rr->u.PX.mode);
396 set_nlink(inode, isonum_733(rr->u.PX.n_links));
397 i_uid_write(inode, isonum_733(rr->u.PX.uid));
398 i_gid_write(inode, isonum_733(rr->u.PX.gid));
399 break;
400 case SIG('P', 'N'):
401 {
402 int high, low;
403 high = isonum_733(rr->u.PN.dev_high);
404 low = isonum_733(rr->u.PN.dev_low);
405 /*
406 * The Rock Ridge standard specifies that if
407 * sizeof(dev_t) <= 4, then the high field is
408 * unused, and the device number is completely
409 * stored in the low field. Some writers may
410 * ignore this subtlety,
411 * and as a result we test to see if the entire
412 * device number is
413 * stored in the low field, and use that.
414 */
415 if ((low & ~0xff) && high == 0) {
416 inode->i_rdev =
417 MKDEV(low >> 8, low & 0xff);
418 } else {
419 inode->i_rdev =
420 MKDEV(high, low);
421 }
422 }
423 break;
424 case SIG('T', 'F'): {
425 int flags, size, slen;
426
427 flags = rr->u.TF.flags & TF_LONG_FORM ? ISO_DATE_LONG_FORM : 0;
428 size = rr->u.TF.flags & TF_LONG_FORM ? 17 : 7;
429 slen = rr->len - 5;
430 /*
431 * Some RRIP writers incorrectly place ctime in the
432 * TF_CREATE field. Try to handle this correctly for
433 * either case.
434 */
435 /* Rock ridge never appears on a High Sierra disk */
436 cnt = 0;
437 if ((rr->u.TF.flags & TF_CREATE) && size <= slen) {
438 inode_set_ctime_to_ts(inode,
439 iso_date(rr->u.TF.data + size * cnt++, flags));
440 slen -= size;
441 }
442 if ((rr->u.TF.flags & TF_MODIFY) && size <= slen) {
443 inode_set_mtime_to_ts(inode,
444 iso_date(rr->u.TF.data + size * cnt++, flags));
445 slen -= size;
446 }
447 if ((rr->u.TF.flags & TF_ACCESS) && size <= slen) {
448 inode_set_atime_to_ts(inode,
449 iso_date(rr->u.TF.data + size * cnt++, flags));
450 slen -= size;
451 }
452 if ((rr->u.TF.flags & TF_ATTRIBUTES) && size <= slen) {
453 inode_set_ctime_to_ts(inode,
454 iso_date(rr->u.TF.data + size * cnt++, flags));
455 slen -= size;
456 }
457 break;
458 }
459 case SIG('S', 'L'):
460 {
461 int slen;
462 struct SL_component *slp;
463 struct SL_component *oldslp;
464 slen = rr->len - 5;
465 slp = &rr->u.SL.link;
466 inode->i_size = symlink_len;
467 while (slen > 1) {
468 rootflag = 0;
469 switch (slp->flags & ~1) {
470 case 0:
471 inode->i_size +=
472 slp->len;
473 break;
474 case 2:
475 inode->i_size += 1;
476 break;
477 case 4:
478 inode->i_size += 2;
479 break;
480 case 8:
481 rootflag = 1;
482 inode->i_size += 1;
483 break;
484 default:
485 printk("Symlink component flag "
486 "not implemented\n");
487 }
488 slen -= slp->len + 2;
489 oldslp = slp;
490 slp = (struct SL_component *)
491 (((char *)slp) + slp->len + 2);
492
493 if (slen < 2) {
494 if (((rr->u.SL.
495 flags & 1) != 0)
496 &&
497 ((oldslp->
498 flags & 1) == 0))
499 inode->i_size +=
500 1;
501 break;
502 }
503
504 /*
505 * If this component record isn't
506 * continued, then append a '/'.
507 */
508 if (!rootflag
509 && (oldslp->flags & 1) == 0)
510 inode->i_size += 1;
511 }
512 }
513 symlink_len = inode->i_size;
514 break;
515 case SIG('R', 'E'):
516 printk(KERN_WARNING "Attempt to read inode for "
517 "relocated directory\n");
518 goto out;
519 case SIG('C', 'L'):
520 if (flags & RR_RELOC_DE) {
521 printk(KERN_ERR
522 "ISOFS: Recursive directory relocation "
523 "is not supported\n");
524 goto eio;
525 }
526 reloc_block = isonum_733(rr->u.CL.location);
527 if (reloc_block == ISOFS_I(inode)->i_iget5_block &&
528 ISOFS_I(inode)->i_iget5_offset == 0) {
529 printk(KERN_ERR
530 "ISOFS: Directory relocation points to "
531 "itself\n");
532 goto eio;
533 }
534 ISOFS_I(inode)->i_first_extent = reloc_block;
535 reloc = isofs_iget_reloc(inode->i_sb, reloc_block, 0);
536 if (IS_ERR(reloc)) {
537 ret = PTR_ERR(reloc);
538 goto out;
539 }
540 inode->i_mode = reloc->i_mode;
541 set_nlink(inode, reloc->i_nlink);
542 inode->i_uid = reloc->i_uid;
543 inode->i_gid = reloc->i_gid;
544 inode->i_rdev = reloc->i_rdev;
545 inode->i_size = reloc->i_size;
546 inode->i_blocks = reloc->i_blocks;
547 inode_set_atime_to_ts(inode, inode_get_atime(reloc));
548 inode_set_ctime_to_ts(inode, inode_get_ctime(reloc));
549 inode_set_mtime_to_ts(inode, inode_get_mtime(reloc));
550 iput(reloc);
551 break;
552 #ifdef CONFIG_ZISOFS
553 case SIG('Z', 'F'): {
554 int algo;
555
556 if (ISOFS_SB(inode->i_sb)->s_nocompress)
557 break;
558 algo = isonum_721(rr->u.ZF.algorithm);
559 if (algo == SIG('p', 'z')) {
560 int block_shift =
561 isonum_711(&rr->u.ZF.parms[1]);
562 if (block_shift > 17) {
563 printk(KERN_WARNING "isofs: "
564 "Can't handle ZF block "
565 "size of 2^%d\n",
566 block_shift);
567 } else {
568 /*
569 * Note: we don't change
570 * i_blocks here
571 */
572 ISOFS_I(inode)->i_file_format =
573 isofs_file_compressed;
574 /*
575 * Parameters to compression
576 * algorithm (header size,
577 * block size)
578 */
579 ISOFS_I(inode)->i_format_parm[0] =
580 isonum_711(&rr->u.ZF.parms[0]);
581 ISOFS_I(inode)->i_format_parm[1] =
582 isonum_711(&rr->u.ZF.parms[1]);
583 inode->i_size =
584 isonum_733(rr->u.ZF.
585 real_size);
586 }
587 } else {
588 printk(KERN_WARNING
589 "isofs: Unknown ZF compression "
590 "algorithm: %c%c\n",
591 rr->u.ZF.algorithm[0],
592 rr->u.ZF.algorithm[1]);
593 }
594 break;
595 }
596 #endif
597 default:
598 break;
599 }
600 }
601 ret = rock_continue(&rs);
602 if (ret == 0)
603 goto repeat;
604 if (ret == 1)
605 ret = 0;
606 out:
607 kfree(rs.buffer);
608 return ret;
609 eio:
610 ret = -EIO;
611 goto out;
612 }
613
get_symlink_chunk(char * rpnt,struct rock_ridge * rr,char * plimit)614 static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
615 {
616 int slen;
617 int rootflag;
618 struct SL_component *oldslp;
619 struct SL_component *slp;
620 slen = rr->len - 5;
621 slp = &rr->u.SL.link;
622 while (slen > 1) {
623 rootflag = 0;
624 switch (slp->flags & ~1) {
625 case 0:
626 if (slp->len > plimit - rpnt)
627 return NULL;
628 memcpy(rpnt, slp->text, slp->len);
629 rpnt += slp->len;
630 break;
631 case 2:
632 if (rpnt >= plimit)
633 return NULL;
634 *rpnt++ = '.';
635 break;
636 case 4:
637 if (2 > plimit - rpnt)
638 return NULL;
639 *rpnt++ = '.';
640 *rpnt++ = '.';
641 break;
642 case 8:
643 if (rpnt >= plimit)
644 return NULL;
645 rootflag = 1;
646 *rpnt++ = '/';
647 break;
648 default:
649 printk("Symlink component flag not implemented (%d)\n",
650 slp->flags);
651 }
652 slen -= slp->len + 2;
653 oldslp = slp;
654 slp = (struct SL_component *)((char *)slp + slp->len + 2);
655
656 if (slen < 2) {
657 /*
658 * If there is another SL record, and this component
659 * record isn't continued, then add a slash.
660 */
661 if ((!rootflag) && (rr->u.SL.flags & 1) &&
662 !(oldslp->flags & 1)) {
663 if (rpnt >= plimit)
664 return NULL;
665 *rpnt++ = '/';
666 }
667 break;
668 }
669
670 /*
671 * If this component record isn't continued, then append a '/'.
672 */
673 if (!rootflag && !(oldslp->flags & 1)) {
674 if (rpnt >= plimit)
675 return NULL;
676 *rpnt++ = '/';
677 }
678 }
679 return rpnt;
680 }
681
parse_rock_ridge_inode(struct iso_directory_record * de,struct inode * inode,int relocated)682 int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode,
683 int relocated)
684 {
685 int flags = relocated ? RR_RELOC_DE : 0;
686 int result = parse_rock_ridge_inode_internal(de, inode, flags);
687
688 /*
689 * if rockridge flag was reset and we didn't look for attributes
690 * behind eventual XA attributes, have a look there
691 */
692 if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
693 && (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
694 result = parse_rock_ridge_inode_internal(de, inode,
695 flags | RR_REGARD_XA);
696 }
697 return result;
698 }
699
700 /*
701 * read_folio() for symlinks: reads symlink contents into the folio and either
702 * makes it uptodate and returns 0 or returns error (-EIO)
703 */
rock_ridge_symlink_read_folio(struct file * file,struct folio * folio)704 static int rock_ridge_symlink_read_folio(struct file *file, struct folio *folio)
705 {
706 struct inode *inode = folio->mapping->host;
707 struct iso_inode_info *ei = ISOFS_I(inode);
708 struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
709 char *link = folio_address(folio);
710 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
711 struct buffer_head *bh;
712 char *rpnt = link;
713 unsigned char *pnt;
714 struct iso_directory_record *raw_de;
715 unsigned long block, offset;
716 int sig;
717 struct rock_ridge *rr;
718 struct rock_state rs;
719 int ret;
720
721 if (!sbi->s_rock)
722 goto error;
723
724 init_rock_state(&rs, inode);
725 block = ei->i_iget5_block;
726 bh = sb_bread(inode->i_sb, block);
727 if (!bh)
728 goto out_noread;
729
730 offset = ei->i_iget5_offset;
731 pnt = (unsigned char *)bh->b_data + offset;
732
733 raw_de = (struct iso_directory_record *)pnt;
734
735 /*
736 * If we go past the end of the buffer, there is some sort of error.
737 */
738 if (offset + *pnt > bufsize)
739 goto out_bad_span;
740
741 /*
742 * Now test for possible Rock Ridge extensions which will override
743 * some of these numbers in the inode structure.
744 */
745
746 setup_rock_ridge(raw_de, inode, &rs);
747
748 repeat:
749 while (rs.len > 2) { /* There may be one byte for padding somewhere */
750 rr = (struct rock_ridge *)rs.chr;
751 if (rr->len < 3)
752 goto out; /* Something got screwed up here */
753 sig = isonum_721(rs.chr);
754 if (rock_check_overflow(&rs, sig))
755 goto out;
756 rs.chr += rr->len;
757 rs.len -= rr->len;
758 if (rs.len < 0)
759 goto out; /* corrupted isofs */
760
761 switch (sig) {
762 case SIG('R', 'R'):
763 if ((rr->u.RR.flags[0] & RR_SL) == 0)
764 goto out;
765 break;
766 case SIG('S', 'P'):
767 if (check_sp(rr, inode))
768 goto out;
769 break;
770 case SIG('S', 'L'):
771 rpnt = get_symlink_chunk(rpnt, rr,
772 link + (PAGE_SIZE - 1));
773 if (rpnt == NULL)
774 goto out;
775 break;
776 case SIG('C', 'E'):
777 /* This tells is if there is a continuation record */
778 rs.cont_extent = isonum_733(rr->u.CE.extent);
779 rs.cont_offset = isonum_733(rr->u.CE.offset);
780 rs.cont_size = isonum_733(rr->u.CE.size);
781 break;
782 default:
783 break;
784 }
785 }
786 ret = rock_continue(&rs);
787 if (ret == 0)
788 goto repeat;
789 if (ret < 0)
790 goto fail;
791
792 if (rpnt == link)
793 goto fail;
794 brelse(bh);
795 *rpnt = '\0';
796 ret = 0;
797 end:
798 folio_end_read(folio, ret == 0);
799 return ret;
800
801 /* error exit from macro */
802 out:
803 kfree(rs.buffer);
804 goto fail;
805 out_noread:
806 printk("unable to read i-node block");
807 goto fail;
808 out_bad_span:
809 printk("symlink spans iso9660 blocks\n");
810 fail:
811 brelse(bh);
812 error:
813 ret = -EIO;
814 goto end;
815 }
816
817 const struct address_space_operations isofs_symlink_aops = {
818 .read_folio = rock_ridge_symlink_read_folio
819 };
820