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