1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2017-2023 Oracle. All Rights Reserved.
4 * Author: Darrick J. Wong <djwong@kernel.org>
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_shared.h"
9#include "xfs_format.h"
10#include "xfs_trans_resv.h"
11#include "xfs_mount.h"
12#include "xfs_log_format.h"
13#include "xfs_inode.h"
14#include "xfs_da_format.h"
15#include "xfs_da_btree.h"
16#include "xfs_attr.h"
17#include "xfs_attr_leaf.h"
18#include "xfs_attr_sf.h"
19#include "scrub/scrub.h"
20#include "scrub/common.h"
21#include "scrub/dabtree.h"
22#include "scrub/attr.h"
23
24/* Free the buffers linked from the xattr buffer. */
25static void
26xchk_xattr_buf_cleanup(
27 void *priv)
28{
29 struct xchk_xattr_buf *ab = priv;
30
31 kvfree(ab->freemap);
32 ab->freemap = NULL;
33 kvfree(ab->usedmap);
34 ab->usedmap = NULL;
35 kvfree(ab->value);
36 ab->value = NULL;
37 ab->value_sz = 0;
38}
39
40/*
41 * Allocate the free space bitmap if we're trying harder; there are leaf blocks
42 * in the attr fork; or we can't tell if there are leaf blocks.
43 */
44static inline bool
45xchk_xattr_want_freemap(
46 struct xfs_scrub *sc)
47{
48 struct xfs_ifork *ifp;
49
50 if (sc->flags & XCHK_TRY_HARDER)
51 return true;
52
53 if (!sc->ip)
54 return true;
55
56 ifp = xfs_ifork_ptr(sc->ip, XFS_ATTR_FORK);
57 if (!ifp)
58 return false;
59
60 return xfs_ifork_has_extents(ifp);
61}
62
63/*
64 * Allocate enough memory to hold an attr value and attr block bitmaps,
65 * reallocating the buffer if necessary. Buffer contents are not preserved
66 * across a reallocation.
67 */
68static int
69xchk_setup_xattr_buf(
70 struct xfs_scrub *sc,
71 size_t value_size)
72{
73 size_t bmp_sz;
74 struct xchk_xattr_buf *ab = sc->buf;
75 void *new_val;
76
77 bmp_sz = sizeof(long) * BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
78
79 if (ab)
80 goto resize_value;
81
82 ab = kvzalloc(sizeof(struct xchk_xattr_buf), XCHK_GFP_FLAGS);
83 if (!ab)
84 return -ENOMEM;
85 sc->buf = ab;
86 sc->buf_cleanup = xchk_xattr_buf_cleanup;
87
88 ab->usedmap = kvmalloc(bmp_sz, XCHK_GFP_FLAGS);
89 if (!ab->usedmap)
90 return -ENOMEM;
91
92 if (xchk_xattr_want_freemap(sc)) {
93 ab->freemap = kvmalloc(bmp_sz, XCHK_GFP_FLAGS);
94 if (!ab->freemap)
95 return -ENOMEM;
96 }
97
98resize_value:
99 if (ab->value_sz >= value_size)
100 return 0;
101
102 if (ab->value) {
103 kvfree(ab->value);
104 ab->value = NULL;
105 ab->value_sz = 0;
106 }
107
108 new_val = kvmalloc(value_size, XCHK_GFP_FLAGS);
109 if (!new_val)
110 return -ENOMEM;
111
112 ab->value = new_val;
113 ab->value_sz = value_size;
114 return 0;
115}
116
117/* Set us up to scrub an inode's extended attributes. */
118int
119xchk_setup_xattr(
120 struct xfs_scrub *sc)
121{
122 int error;
123
124 /*
125 * We failed to get memory while checking attrs, so this time try to
126 * get all the memory we're ever going to need. Allocate the buffer
127 * without the inode lock held, which means we can sleep.
128 */
129 if (sc->flags & XCHK_TRY_HARDER) {
130 error = xchk_setup_xattr_buf(sc, XATTR_SIZE_MAX);
131 if (error)
132 return error;
133 }
134
135 return xchk_setup_inode_contents(sc, 0);
136}
137
138/* Extended Attributes */
139
140struct xchk_xattr {
141 struct xfs_attr_list_context context;
142 struct xfs_scrub *sc;
143};
144
145/*
146 * Check that an extended attribute key can be looked up by hash.
147 *
148 * We use the XFS attribute list iterator (i.e. xfs_attr_list_ilocked)
149 * to call this function for every attribute key in an inode. Once
150 * we're here, we load the attribute value to see if any errors happen,
151 * or if we get more or less data than we expected.
152 */
153static void
154xchk_xattr_listent(
155 struct xfs_attr_list_context *context,
156 int flags,
157 unsigned char *name,
158 int namelen,
159 int valuelen)
160{
161 struct xfs_da_args args = {
162 .op_flags = XFS_DA_OP_NOTIME,
163 .attr_filter = flags & XFS_ATTR_NSP_ONDISK_MASK,
164 .geo = context->dp->i_mount->m_attr_geo,
165 .whichfork = XFS_ATTR_FORK,
166 .dp = context->dp,
167 .name = name,
168 .namelen = namelen,
169 .hashval = xfs_da_hashname(name, namelen),
170 .trans = context->tp,
171 .valuelen = valuelen,
172 };
173 struct xchk_xattr_buf *ab;
174 struct xchk_xattr *sx;
175 int error = 0;
176
177 sx = container_of(context, struct xchk_xattr, context);
178 ab = sx->sc->buf;
179
180 if (xchk_should_terminate(sx->sc, &error)) {
181 context->seen_enough = error;
182 return;
183 }
184
185 if (flags & XFS_ATTR_INCOMPLETE) {
186 /* Incomplete attr key, just mark the inode for preening. */
187 xchk_ino_set_preen(sx->sc, context->dp->i_ino);
188 return;
189 }
190
191 /* Only one namespace bit allowed. */
192 if (hweight32(flags & XFS_ATTR_NSP_ONDISK_MASK) > 1) {
193 xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, args.blkno);
194 goto fail_xref;
195 }
196
197 /* Does this name make sense? */
198 if (!xfs_attr_namecheck(name, namelen)) {
199 xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, args.blkno);
200 goto fail_xref;
201 }
202
203 /*
204 * Local xattr values are stored in the attr leaf block, so we don't
205 * need to retrieve the value from a remote block to detect corruption
206 * problems.
207 */
208 if (flags & XFS_ATTR_LOCAL)
209 goto fail_xref;
210
211 /*
212 * Try to allocate enough memory to extrat the attr value. If that
213 * doesn't work, we overload the seen_enough variable to convey
214 * the error message back to the main scrub function.
215 */
216 error = xchk_setup_xattr_buf(sx->sc, valuelen);
217 if (error == -ENOMEM)
218 error = -EDEADLOCK;
219 if (error) {
220 context->seen_enough = error;
221 return;
222 }
223
224 args.value = ab->value;
225
226 error = xfs_attr_get_ilocked(&args);
227 /* ENODATA means the hash lookup failed and the attr is bad */
228 if (error == -ENODATA)
229 error = -EFSCORRUPTED;
230 if (!xchk_fblock_process_error(sx->sc, XFS_ATTR_FORK, args.blkno,
231 &error))
232 goto fail_xref;
233 if (args.valuelen != valuelen)
234 xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK,
235 args.blkno);
236fail_xref:
237 if (sx->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
238 context->seen_enough = 1;
239 return;
240}
241
242/*
243 * Mark a range [start, start+len) in this map. Returns true if the
244 * region was free, and false if there's a conflict or a problem.
245 *
246 * Within a char, the lowest bit of the char represents the byte with
247 * the smallest address
248 */
249STATIC bool
250xchk_xattr_set_map(
251 struct xfs_scrub *sc,
252 unsigned long *map,
253 unsigned int start,
254 unsigned int len)
255{
256 unsigned int mapsize = sc->mp->m_attr_geo->blksize;
257 bool ret = true;
258
259 if (start >= mapsize)
260 return false;
261 if (start + len > mapsize) {
262 len = mapsize - start;
263 ret = false;
264 }
265
266 if (find_next_bit(map, mapsize, start) < start + len)
267 ret = false;
268 bitmap_set(map, start, len);
269
270 return ret;
271}
272
273/*
274 * Check the leaf freemap from the usage bitmap. Returns false if the
275 * attr freemap has problems or points to used space.
276 */
277STATIC bool
278xchk_xattr_check_freemap(
279 struct xfs_scrub *sc,
280 struct xfs_attr3_icleaf_hdr *leafhdr)
281{
282 struct xchk_xattr_buf *ab = sc->buf;
283 unsigned int mapsize = sc->mp->m_attr_geo->blksize;
284 int i;
285
286 /* Construct bitmap of freemap contents. */
287 bitmap_zero(ab->freemap, mapsize);
288 for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
289 if (!xchk_xattr_set_map(sc, ab->freemap,
290 leafhdr->freemap[i].base,
291 leafhdr->freemap[i].size))
292 return false;
293 }
294
295 /* Look for bits that are set in freemap and are marked in use. */
296 return !bitmap_intersects(ab->freemap, ab->usedmap, mapsize);
297}
298
299/*
300 * Check this leaf entry's relations to everything else.
301 * Returns the number of bytes used for the name/value data.
302 */
303STATIC void
304xchk_xattr_entry(
305 struct xchk_da_btree *ds,
306 int level,
307 char *buf_end,
308 struct xfs_attr_leafblock *leaf,
309 struct xfs_attr3_icleaf_hdr *leafhdr,
310 struct xfs_attr_leaf_entry *ent,
311 int idx,
312 unsigned int *usedbytes,
313 __u32 *last_hashval)
314{
315 struct xfs_mount *mp = ds->state->mp;
316 struct xchk_xattr_buf *ab = ds->sc->buf;
317 char *name_end;
318 struct xfs_attr_leaf_name_local *lentry;
319 struct xfs_attr_leaf_name_remote *rentry;
320 unsigned int nameidx;
321 unsigned int namesize;
322
323 if (ent->pad2 != 0)
324 xchk_da_set_corrupt(ds, level);
325
326 /* Hash values in order? */
327 if (be32_to_cpu(ent->hashval) < *last_hashval)
328 xchk_da_set_corrupt(ds, level);
329 *last_hashval = be32_to_cpu(ent->hashval);
330
331 nameidx = be16_to_cpu(ent->nameidx);
332 if (nameidx < leafhdr->firstused ||
333 nameidx >= mp->m_attr_geo->blksize) {
334 xchk_da_set_corrupt(ds, level);
335 return;
336 }
337
338 /* Check the name information. */
339 if (ent->flags & XFS_ATTR_LOCAL) {
340 lentry = xfs_attr3_leaf_name_local(leaf, idx);
341 namesize = xfs_attr_leaf_entsize_local(lentry->namelen,
342 be16_to_cpu(lentry->valuelen));
343 name_end = (char *)lentry + namesize;
344 if (lentry->namelen == 0)
345 xchk_da_set_corrupt(ds, level);
346 } else {
347 rentry = xfs_attr3_leaf_name_remote(leaf, idx);
348 namesize = xfs_attr_leaf_entsize_remote(rentry->namelen);
349 name_end = (char *)rentry + namesize;
350 if (rentry->namelen == 0 || rentry->valueblk == 0)
351 xchk_da_set_corrupt(ds, level);
352 }
353 if (name_end > buf_end)
354 xchk_da_set_corrupt(ds, level);
355
356 if (!xchk_xattr_set_map(ds->sc, ab->usedmap, nameidx, namesize))
357 xchk_da_set_corrupt(ds, level);
358 if (!(ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
359 *usedbytes += namesize;
360}
361
362/* Scrub an attribute leaf. */
363STATIC int
364xchk_xattr_block(
365 struct xchk_da_btree *ds,
366 int level)
367{
368 struct xfs_attr3_icleaf_hdr leafhdr;
369 struct xfs_mount *mp = ds->state->mp;
370 struct xfs_da_state_blk *blk = &ds->state->path.blk[level];
371 struct xfs_buf *bp = blk->bp;
372 xfs_dablk_t *last_checked = ds->private;
373 struct xfs_attr_leafblock *leaf = bp->b_addr;
374 struct xfs_attr_leaf_entry *ent;
375 struct xfs_attr_leaf_entry *entries;
376 struct xchk_xattr_buf *ab = ds->sc->buf;
377 char *buf_end;
378 size_t off;
379 __u32 last_hashval = 0;
380 unsigned int usedbytes = 0;
381 unsigned int hdrsize;
382 int i;
383
384 if (*last_checked == blk->blkno)
385 return 0;
386
387 *last_checked = blk->blkno;
388 bitmap_zero(ab->usedmap, mp->m_attr_geo->blksize);
389
390 /* Check all the padding. */
391 if (xfs_has_crc(ds->sc->mp)) {
392 struct xfs_attr3_leafblock *leaf3 = bp->b_addr;
393
394 if (leaf3->hdr.pad1 != 0 || leaf3->hdr.pad2 != 0 ||
395 leaf3->hdr.info.hdr.pad != 0)
396 xchk_da_set_corrupt(ds, level);
397 } else {
398 if (leaf->hdr.pad1 != 0 || leaf->hdr.info.pad != 0)
399 xchk_da_set_corrupt(ds, level);
400 }
401
402 /* Check the leaf header */
403 xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
404 hdrsize = xfs_attr3_leaf_hdr_size(leaf);
405
406 if (leafhdr.usedbytes > mp->m_attr_geo->blksize)
407 xchk_da_set_corrupt(ds, level);
408 if (leafhdr.firstused > mp->m_attr_geo->blksize)
409 xchk_da_set_corrupt(ds, level);
410 if (leafhdr.firstused < hdrsize)
411 xchk_da_set_corrupt(ds, level);
412 if (!xchk_xattr_set_map(ds->sc, ab->usedmap, 0, hdrsize))
413 xchk_da_set_corrupt(ds, level);
414
415 if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
416 goto out;
417
418 entries = xfs_attr3_leaf_entryp(leaf);
419 if ((char *)&entries[leafhdr.count] > (char *)leaf + leafhdr.firstused)
420 xchk_da_set_corrupt(ds, level);
421
422 buf_end = (char *)bp->b_addr + mp->m_attr_geo->blksize;
423 for (i = 0, ent = entries; i < leafhdr.count; ent++, i++) {
424 /* Mark the leaf entry itself. */
425 off = (char *)ent - (char *)leaf;
426 if (!xchk_xattr_set_map(ds->sc, ab->usedmap, off,
427 sizeof(xfs_attr_leaf_entry_t))) {
428 xchk_da_set_corrupt(ds, level);
429 goto out;
430 }
431
432 /* Check the entry and nameval. */
433 xchk_xattr_entry(ds, level, buf_end, leaf, &leafhdr,
434 ent, i, &usedbytes, &last_hashval);
435
436 if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
437 goto out;
438 }
439
440 if (!xchk_xattr_check_freemap(ds->sc, &leafhdr))
441 xchk_da_set_corrupt(ds, level);
442
443 if (leafhdr.usedbytes != usedbytes)
444 xchk_da_set_corrupt(ds, level);
445
446out:
447 return 0;
448}
449
450/* Scrub a attribute btree record. */
451STATIC int
452xchk_xattr_rec(
453 struct xchk_da_btree *ds,
454 int level)
455{
456 struct xfs_mount *mp = ds->state->mp;
457 struct xfs_da_state_blk *blk = &ds->state->path.blk[level];
458 struct xfs_attr_leaf_name_local *lentry;
459 struct xfs_attr_leaf_name_remote *rentry;
460 struct xfs_buf *bp;
461 struct xfs_attr_leaf_entry *ent;
462 xfs_dahash_t calc_hash;
463 xfs_dahash_t hash;
464 int nameidx;
465 int hdrsize;
466 unsigned int badflags;
467 int error;
468
469 ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
470
471 ent = xfs_attr3_leaf_entryp(blk->bp->b_addr) + blk->index;
472
473 /* Check the whole block, if necessary. */
474 error = xchk_xattr_block(ds, level);
475 if (error)
476 goto out;
477 if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
478 goto out;
479
480 /* Check the hash of the entry. */
481 error = xchk_da_btree_hash(ds, level, &ent->hashval);
482 if (error)
483 goto out;
484
485 /* Find the attr entry's location. */
486 bp = blk->bp;
487 hdrsize = xfs_attr3_leaf_hdr_size(bp->b_addr);
488 nameidx = be16_to_cpu(ent->nameidx);
489 if (nameidx < hdrsize || nameidx >= mp->m_attr_geo->blksize) {
490 xchk_da_set_corrupt(ds, level);
491 goto out;
492 }
493
494 /* Retrieve the entry and check it. */
495 hash = be32_to_cpu(ent->hashval);
496 badflags = ~(XFS_ATTR_LOCAL | XFS_ATTR_ROOT | XFS_ATTR_SECURE |
497 XFS_ATTR_INCOMPLETE);
498 if ((ent->flags & badflags) != 0)
499 xchk_da_set_corrupt(ds, level);
500 if (ent->flags & XFS_ATTR_LOCAL) {
501 lentry = (struct xfs_attr_leaf_name_local *)
502 (((char *)bp->b_addr) + nameidx);
503 if (lentry->namelen <= 0) {
504 xchk_da_set_corrupt(ds, level);
505 goto out;
506 }
507 calc_hash = xfs_da_hashname(lentry->nameval, lentry->namelen);
508 } else {
509 rentry = (struct xfs_attr_leaf_name_remote *)
510 (((char *)bp->b_addr) + nameidx);
511 if (rentry->namelen <= 0) {
512 xchk_da_set_corrupt(ds, level);
513 goto out;
514 }
515 calc_hash = xfs_da_hashname(rentry->name, rentry->namelen);
516 }
517 if (calc_hash != hash)
518 xchk_da_set_corrupt(ds, level);
519
520out:
521 return error;
522}
523
524/* Check space usage of shortform attrs. */
525STATIC int
526xchk_xattr_check_sf(
527 struct xfs_scrub *sc)
528{
529 struct xchk_xattr_buf *ab = sc->buf;
530 struct xfs_ifork *ifp = &sc->ip->i_af;
531 struct xfs_attr_sf_hdr *sf = ifp->if_data;
532 struct xfs_attr_sf_entry *sfe = xfs_attr_sf_firstentry(sf);
533 struct xfs_attr_sf_entry *next;
534 unsigned char *end = ifp->if_data + ifp->if_bytes;
535 int i;
536 int error = 0;
537
538 bitmap_zero(ab->usedmap, ifp->if_bytes);
539 xchk_xattr_set_map(sc, ab->usedmap, 0, sizeof(*sf));
540
541 if ((unsigned char *)sfe > end) {
542 xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
543 return 0;
544 }
545
546 for (i = 0; i < sf->count; i++) {
547 unsigned char *name = sfe->nameval;
548 unsigned char *value = &sfe->nameval[sfe->namelen];
549
550 if (xchk_should_terminate(sc, &error))
551 return error;
552
553 next = xfs_attr_sf_nextentry(sfe);
554 if ((unsigned char *)next > end) {
555 xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
556 break;
557 }
558
559 if (!xchk_xattr_set_map(sc, ab->usedmap,
560 (char *)sfe - (char *)sf,
561 sizeof(struct xfs_attr_sf_entry))) {
562 xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
563 break;
564 }
565
566 if (!xchk_xattr_set_map(sc, ab->usedmap,
567 (char *)name - (char *)sf,
568 sfe->namelen)) {
569 xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
570 break;
571 }
572
573 if (!xchk_xattr_set_map(sc, ab->usedmap,
574 (char *)value - (char *)sf,
575 sfe->valuelen)) {
576 xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
577 break;
578 }
579
580 sfe = next;
581 }
582
583 return 0;
584}
585
586/* Scrub the extended attribute metadata. */
587int
588xchk_xattr(
589 struct xfs_scrub *sc)
590{
591 struct xchk_xattr sx = {
592 .sc = sc,
593 .context = {
594 .dp = sc->ip,
595 .tp = sc->tp,
596 .resynch = 1,
597 .put_listent = xchk_xattr_listent,
598 .allow_incomplete = true,
599 },
600 };
601 xfs_dablk_t last_checked = -1U;
602 int error = 0;
603
604 if (!xfs_inode_hasattr(sc->ip))
605 return -ENOENT;
606
607 /* Allocate memory for xattr checking. */
608 error = xchk_setup_xattr_buf(sc, 0);
609 if (error == -ENOMEM)
610 return -EDEADLOCK;
611 if (error)
612 return error;
613
614 /* Check the physical structure of the xattr. */
615 if (sc->ip->i_af.if_format == XFS_DINODE_FMT_LOCAL)
616 error = xchk_xattr_check_sf(sc);
617 else
618 error = xchk_da_btree(sc, XFS_ATTR_FORK, xchk_xattr_rec,
619 &last_checked);
620 if (error)
621 return error;
622
623 if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
624 return 0;
625
626 /*
627 * Look up every xattr in this file by name and hash.
628 *
629 * Use the backend implementation of xfs_attr_list to call
630 * xchk_xattr_listent on every attribute key in this inode.
631 * In other words, we use the same iterator/callback mechanism
632 * that listattr uses to scrub extended attributes, though in our
633 * _listent function, we check the value of the attribute.
634 *
635 * The VFS only locks i_rwsem when modifying attrs, so keep all
636 * three locks held because that's the only way to ensure we're
637 * the only thread poking into the da btree. We traverse the da
638 * btree while holding a leaf buffer locked for the xattr name
639 * iteration, which doesn't really follow the usual buffer
640 * locking order.
641 */
642 error = xfs_attr_list_ilocked(&sx.context);
643 if (!xchk_fblock_process_error(sc, XFS_ATTR_FORK, 0, &error))
644 return error;
645
646 /* Did our listent function try to return any errors? */
647 if (sx.context.seen_enough < 0)
648 return sx.context.seen_enough;
649
650 return 0;
651}
652

source code of linux/fs/xfs/scrub/attr.c