1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2017 Oracle. All Rights Reserved. 4 * Author: Darrick J. Wong <darrick.wong@oracle.com> 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_defer.h" 13 #include "xfs_btree.h" 14 #include "xfs_bit.h" 15 #include "xfs_log_format.h" 16 #include "xfs_trans.h" 17 #include "xfs_sb.h" 18 #include "xfs_inode.h" 19 #include "xfs_da_format.h" 20 #include "xfs_da_btree.h" 21 #include "xfs_dir2.h" 22 #include "xfs_attr.h" 23 #include "xfs_attr_leaf.h" 24 #include "scrub/xfs_scrub.h" 25 #include "scrub/scrub.h" 26 #include "scrub/common.h" 27 #include "scrub/dabtree.h" 28 #include "scrub/trace.h" 29 30 #include <linux/posix_acl_xattr.h> 31 #include <linux/xattr.h> 32 33 /* Set us up to scrub an inode's extended attributes. */ 34 int 35 xchk_setup_xattr( 36 struct xfs_scrub *sc, 37 struct xfs_inode *ip) 38 { 39 size_t sz; 40 41 /* 42 * Allocate the buffer without the inode lock held. We need enough 43 * space to read every xattr value in the file or enough space to 44 * hold three copies of the xattr free space bitmap. (Not both at 45 * the same time.) 46 */ 47 sz = max_t(size_t, XATTR_SIZE_MAX, 3 * sizeof(long) * 48 BITS_TO_LONGS(sc->mp->m_attr_geo->blksize)); 49 sc->buf = kmem_zalloc_large(sz, KM_SLEEP); 50 if (!sc->buf) 51 return -ENOMEM; 52 53 return xchk_setup_inode_contents(sc, ip, 0); 54 } 55 56 /* Extended Attributes */ 57 58 struct xchk_xattr { 59 struct xfs_attr_list_context context; 60 struct xfs_scrub *sc; 61 }; 62 63 /* 64 * Check that an extended attribute key can be looked up by hash. 65 * 66 * We use the XFS attribute list iterator (i.e. xfs_attr_list_int_ilocked) 67 * to call this function for every attribute key in an inode. Once 68 * we're here, we load the attribute value to see if any errors happen, 69 * or if we get more or less data than we expected. 70 */ 71 static void 72 xchk_xattr_listent( 73 struct xfs_attr_list_context *context, 74 int flags, 75 unsigned char *name, 76 int namelen, 77 int valuelen) 78 { 79 struct xchk_xattr *sx; 80 struct xfs_da_args args = { NULL }; 81 int error = 0; 82 83 sx = container_of(context, struct xchk_xattr, context); 84 85 if (xchk_should_terminate(sx->sc, &error)) { 86 context->seen_enough = 1; 87 return; 88 } 89 90 if (flags & XFS_ATTR_INCOMPLETE) { 91 /* Incomplete attr key, just mark the inode for preening. */ 92 xchk_ino_set_preen(sx->sc, context->dp->i_ino); 93 return; 94 } 95 96 /* Does this name make sense? */ 97 if (!xfs_attr_namecheck(name, namelen)) { 98 xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, args.blkno); 99 return; 100 } 101 102 args.flags = ATTR_KERNOTIME; 103 if (flags & XFS_ATTR_ROOT) 104 args.flags |= ATTR_ROOT; 105 else if (flags & XFS_ATTR_SECURE) 106 args.flags |= ATTR_SECURE; 107 args.geo = context->dp->i_mount->m_attr_geo; 108 args.whichfork = XFS_ATTR_FORK; 109 args.dp = context->dp; 110 args.name = name; 111 args.namelen = namelen; 112 args.hashval = xfs_da_hashname(args.name, args.namelen); 113 args.trans = context->tp; 114 args.value = sx->sc->buf; 115 args.valuelen = XATTR_SIZE_MAX; 116 117 error = xfs_attr_get_ilocked(context->dp, &args); 118 if (error == -EEXIST) 119 error = 0; 120 if (!xchk_fblock_process_error(sx->sc, XFS_ATTR_FORK, args.blkno, 121 &error)) 122 goto fail_xref; 123 if (args.valuelen != valuelen) 124 xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, 125 args.blkno); 126 fail_xref: 127 if (sx->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) 128 context->seen_enough = 1; 129 return; 130 } 131 132 /* 133 * Mark a range [start, start+len) in this map. Returns true if the 134 * region was free, and false if there's a conflict or a problem. 135 * 136 * Within a char, the lowest bit of the char represents the byte with 137 * the smallest address 138 */ 139 STATIC bool 140 xchk_xattr_set_map( 141 struct xfs_scrub *sc, 142 unsigned long *map, 143 unsigned int start, 144 unsigned int len) 145 { 146 unsigned int mapsize = sc->mp->m_attr_geo->blksize; 147 bool ret = true; 148 149 if (start >= mapsize) 150 return false; 151 if (start + len > mapsize) { 152 len = mapsize - start; 153 ret = false; 154 } 155 156 if (find_next_bit(map, mapsize, start) < start + len) 157 ret = false; 158 bitmap_set(map, start, len); 159 160 return ret; 161 } 162 163 /* 164 * Check the leaf freemap from the usage bitmap. Returns false if the 165 * attr freemap has problems or points to used space. 166 */ 167 STATIC bool 168 xchk_xattr_check_freemap( 169 struct xfs_scrub *sc, 170 unsigned long *map, 171 struct xfs_attr3_icleaf_hdr *leafhdr) 172 { 173 unsigned long *freemap; 174 unsigned long *dstmap; 175 unsigned int mapsize = sc->mp->m_attr_geo->blksize; 176 int i; 177 178 /* Construct bitmap of freemap contents. */ 179 freemap = (unsigned long *)sc->buf + BITS_TO_LONGS(mapsize); 180 bitmap_zero(freemap, mapsize); 181 for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) { 182 if (!xchk_xattr_set_map(sc, freemap, 183 leafhdr->freemap[i].base, 184 leafhdr->freemap[i].size)) 185 return false; 186 } 187 188 /* Look for bits that are set in freemap and are marked in use. */ 189 dstmap = freemap + BITS_TO_LONGS(mapsize); 190 return bitmap_and(dstmap, freemap, map, mapsize) == 0; 191 } 192 193 /* 194 * Check this leaf entry's relations to everything else. 195 * Returns the number of bytes used for the name/value data. 196 */ 197 STATIC void 198 xchk_xattr_entry( 199 struct xchk_da_btree *ds, 200 int level, 201 char *buf_end, 202 struct xfs_attr_leafblock *leaf, 203 struct xfs_attr3_icleaf_hdr *leafhdr, 204 unsigned long *usedmap, 205 struct xfs_attr_leaf_entry *ent, 206 int idx, 207 unsigned int *usedbytes, 208 __u32 *last_hashval) 209 { 210 struct xfs_mount *mp = ds->state->mp; 211 char *name_end; 212 struct xfs_attr_leaf_name_local *lentry; 213 struct xfs_attr_leaf_name_remote *rentry; 214 unsigned int nameidx; 215 unsigned int namesize; 216 217 if (ent->pad2 != 0) 218 xchk_da_set_corrupt(ds, level); 219 220 /* Hash values in order? */ 221 if (be32_to_cpu(ent->hashval) < *last_hashval) 222 xchk_da_set_corrupt(ds, level); 223 *last_hashval = be32_to_cpu(ent->hashval); 224 225 nameidx = be16_to_cpu(ent->nameidx); 226 if (nameidx < leafhdr->firstused || 227 nameidx >= mp->m_attr_geo->blksize) { 228 xchk_da_set_corrupt(ds, level); 229 return; 230 } 231 232 /* Check the name information. */ 233 if (ent->flags & XFS_ATTR_LOCAL) { 234 lentry = xfs_attr3_leaf_name_local(leaf, idx); 235 namesize = xfs_attr_leaf_entsize_local(lentry->namelen, 236 be16_to_cpu(lentry->valuelen)); 237 name_end = (char *)lentry + namesize; 238 if (lentry->namelen == 0) 239 xchk_da_set_corrupt(ds, level); 240 } else { 241 rentry = xfs_attr3_leaf_name_remote(leaf, idx); 242 namesize = xfs_attr_leaf_entsize_remote(rentry->namelen); 243 name_end = (char *)rentry + namesize; 244 if (rentry->namelen == 0 || rentry->valueblk == 0) 245 xchk_da_set_corrupt(ds, level); 246 } 247 if (name_end > buf_end) 248 xchk_da_set_corrupt(ds, level); 249 250 if (!xchk_xattr_set_map(ds->sc, usedmap, nameidx, namesize)) 251 xchk_da_set_corrupt(ds, level); 252 if (!(ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)) 253 *usedbytes += namesize; 254 } 255 256 /* Scrub an attribute leaf. */ 257 STATIC int 258 xchk_xattr_block( 259 struct xchk_da_btree *ds, 260 int level) 261 { 262 struct xfs_attr3_icleaf_hdr leafhdr; 263 struct xfs_mount *mp = ds->state->mp; 264 struct xfs_da_state_blk *blk = &ds->state->path.blk[level]; 265 struct xfs_buf *bp = blk->bp; 266 xfs_dablk_t *last_checked = ds->private; 267 struct xfs_attr_leafblock *leaf = bp->b_addr; 268 struct xfs_attr_leaf_entry *ent; 269 struct xfs_attr_leaf_entry *entries; 270 unsigned long *usedmap = ds->sc->buf; 271 char *buf_end; 272 size_t off; 273 __u32 last_hashval = 0; 274 unsigned int usedbytes = 0; 275 unsigned int hdrsize; 276 int i; 277 278 if (*last_checked == blk->blkno) 279 return 0; 280 *last_checked = blk->blkno; 281 bitmap_zero(usedmap, mp->m_attr_geo->blksize); 282 283 /* Check all the padding. */ 284 if (xfs_sb_version_hascrc(&ds->sc->mp->m_sb)) { 285 struct xfs_attr3_leafblock *leaf = bp->b_addr; 286 287 if (leaf->hdr.pad1 != 0 || leaf->hdr.pad2 != 0 || 288 leaf->hdr.info.hdr.pad != 0) 289 xchk_da_set_corrupt(ds, level); 290 } else { 291 if (leaf->hdr.pad1 != 0 || leaf->hdr.info.pad != 0) 292 xchk_da_set_corrupt(ds, level); 293 } 294 295 /* Check the leaf header */ 296 xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf); 297 hdrsize = xfs_attr3_leaf_hdr_size(leaf); 298 299 if (leafhdr.usedbytes > mp->m_attr_geo->blksize) 300 xchk_da_set_corrupt(ds, level); 301 if (leafhdr.firstused > mp->m_attr_geo->blksize) 302 xchk_da_set_corrupt(ds, level); 303 if (leafhdr.firstused < hdrsize) 304 xchk_da_set_corrupt(ds, level); 305 if (!xchk_xattr_set_map(ds->sc, usedmap, 0, hdrsize)) 306 xchk_da_set_corrupt(ds, level); 307 308 if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) 309 goto out; 310 311 entries = xfs_attr3_leaf_entryp(leaf); 312 if ((char *)&entries[leafhdr.count] > (char *)leaf + leafhdr.firstused) 313 xchk_da_set_corrupt(ds, level); 314 315 buf_end = (char *)bp->b_addr + mp->m_attr_geo->blksize; 316 for (i = 0, ent = entries; i < leafhdr.count; ent++, i++) { 317 /* Mark the leaf entry itself. */ 318 off = (char *)ent - (char *)leaf; 319 if (!xchk_xattr_set_map(ds->sc, usedmap, off, 320 sizeof(xfs_attr_leaf_entry_t))) { 321 xchk_da_set_corrupt(ds, level); 322 goto out; 323 } 324 325 /* Check the entry and nameval. */ 326 xchk_xattr_entry(ds, level, buf_end, leaf, &leafhdr, 327 usedmap, ent, i, &usedbytes, &last_hashval); 328 329 if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) 330 goto out; 331 } 332 333 if (!xchk_xattr_check_freemap(ds->sc, usedmap, &leafhdr)) 334 xchk_da_set_corrupt(ds, level); 335 336 if (leafhdr.usedbytes != usedbytes) 337 xchk_da_set_corrupt(ds, level); 338 339 out: 340 return 0; 341 } 342 343 /* Scrub a attribute btree record. */ 344 STATIC int 345 xchk_xattr_rec( 346 struct xchk_da_btree *ds, 347 int level, 348 void *rec) 349 { 350 struct xfs_mount *mp = ds->state->mp; 351 struct xfs_attr_leaf_entry *ent = rec; 352 struct xfs_da_state_blk *blk; 353 struct xfs_attr_leaf_name_local *lentry; 354 struct xfs_attr_leaf_name_remote *rentry; 355 struct xfs_buf *bp; 356 xfs_dahash_t calc_hash; 357 xfs_dahash_t hash; 358 int nameidx; 359 int hdrsize; 360 unsigned int badflags; 361 int error; 362 363 blk = &ds->state->path.blk[level]; 364 365 /* Check the whole block, if necessary. */ 366 error = xchk_xattr_block(ds, level); 367 if (error) 368 goto out; 369 if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) 370 goto out; 371 372 /* Check the hash of the entry. */ 373 error = xchk_da_btree_hash(ds, level, &ent->hashval); 374 if (error) 375 goto out; 376 377 /* Find the attr entry's location. */ 378 bp = blk->bp; 379 hdrsize = xfs_attr3_leaf_hdr_size(bp->b_addr); 380 nameidx = be16_to_cpu(ent->nameidx); 381 if (nameidx < hdrsize || nameidx >= mp->m_attr_geo->blksize) { 382 xchk_da_set_corrupt(ds, level); 383 goto out; 384 } 385 386 /* Retrieve the entry and check it. */ 387 hash = be32_to_cpu(ent->hashval); 388 badflags = ~(XFS_ATTR_LOCAL | XFS_ATTR_ROOT | XFS_ATTR_SECURE | 389 XFS_ATTR_INCOMPLETE); 390 if ((ent->flags & badflags) != 0) 391 xchk_da_set_corrupt(ds, level); 392 if (ent->flags & XFS_ATTR_LOCAL) { 393 lentry = (struct xfs_attr_leaf_name_local *) 394 (((char *)bp->b_addr) + nameidx); 395 if (lentry->namelen <= 0) { 396 xchk_da_set_corrupt(ds, level); 397 goto out; 398 } 399 calc_hash = xfs_da_hashname(lentry->nameval, lentry->namelen); 400 } else { 401 rentry = (struct xfs_attr_leaf_name_remote *) 402 (((char *)bp->b_addr) + nameidx); 403 if (rentry->namelen <= 0) { 404 xchk_da_set_corrupt(ds, level); 405 goto out; 406 } 407 calc_hash = xfs_da_hashname(rentry->name, rentry->namelen); 408 } 409 if (calc_hash != hash) 410 xchk_da_set_corrupt(ds, level); 411 412 out: 413 return error; 414 } 415 416 /* Scrub the extended attribute metadata. */ 417 int 418 xchk_xattr( 419 struct xfs_scrub *sc) 420 { 421 struct xchk_xattr sx; 422 struct attrlist_cursor_kern cursor = { 0 }; 423 xfs_dablk_t last_checked = -1U; 424 int error = 0; 425 426 if (!xfs_inode_hasattr(sc->ip)) 427 return -ENOENT; 428 429 memset(&sx, 0, sizeof(sx)); 430 /* Check attribute tree structure */ 431 error = xchk_da_btree(sc, XFS_ATTR_FORK, xchk_xattr_rec, 432 &last_checked); 433 if (error) 434 goto out; 435 436 if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) 437 goto out; 438 439 /* Check that every attr key can also be looked up by hash. */ 440 sx.context.dp = sc->ip; 441 sx.context.cursor = &cursor; 442 sx.context.resynch = 1; 443 sx.context.put_listent = xchk_xattr_listent; 444 sx.context.tp = sc->tp; 445 sx.context.flags = ATTR_INCOMPLETE; 446 sx.sc = sc; 447 448 /* 449 * Look up every xattr in this file by name. 450 * 451 * Use the backend implementation of xfs_attr_list to call 452 * xchk_xattr_listent on every attribute key in this inode. 453 * In other words, we use the same iterator/callback mechanism 454 * that listattr uses to scrub extended attributes, though in our 455 * _listent function, we check the value of the attribute. 456 * 457 * The VFS only locks i_rwsem when modifying attrs, so keep all 458 * three locks held because that's the only way to ensure we're 459 * the only thread poking into the da btree. We traverse the da 460 * btree while holding a leaf buffer locked for the xattr name 461 * iteration, which doesn't really follow the usual buffer 462 * locking order. 463 */ 464 error = xfs_attr_list_int_ilocked(&sx.context); 465 if (!xchk_fblock_process_error(sc, XFS_ATTR_FORK, 0, &error)) 466 goto out; 467 out: 468 return error; 469 } 470