1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Copyright (C) 2021-2022, Alibaba Cloud
6 */
7 #include <linux/security.h>
8 #include <linux/xxhash.h>
9 #include "xattr.h"
10
11 struct erofs_xattr_iter {
12 struct super_block *sb;
13 struct erofs_buf buf;
14 erofs_off_t pos;
15 void *kaddr;
16
17 char *buffer;
18 int buffer_size, buffer_ofs;
19
20 /* getxattr */
21 int index, infix_len;
22 struct qstr name;
23
24 /* listxattr */
25 struct dentry *dentry;
26 };
27
erofs_init_inode_xattrs(struct inode * inode)28 static int erofs_init_inode_xattrs(struct inode *inode)
29 {
30 struct erofs_inode *const vi = EROFS_I(inode);
31 struct erofs_xattr_iter it;
32 unsigned int i;
33 struct erofs_xattr_ibody_header *ih;
34 struct super_block *sb = inode->i_sb;
35 int ret = 0;
36
37 /* the most case is that xattrs of this inode are initialized. */
38 if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) {
39 /*
40 * paired with smp_mb() at the end of the function to ensure
41 * fields will only be observed after the bit is set.
42 */
43 smp_mb();
44 return 0;
45 }
46
47 if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE))
48 return -ERESTARTSYS;
49
50 /* someone has initialized xattrs for us? */
51 if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
52 goto out_unlock;
53
54 /*
55 * bypass all xattr operations if ->xattr_isize is not greater than
56 * sizeof(struct erofs_xattr_ibody_header), in detail:
57 * 1) it is not enough to contain erofs_xattr_ibody_header then
58 * ->xattr_isize should be 0 (it means no xattr);
59 * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk
60 * undefined right now (maybe use later with some new sb feature).
61 */
62 if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) {
63 erofs_err(sb,
64 "xattr_isize %d of nid %llu is not supported yet",
65 vi->xattr_isize, vi->nid);
66 ret = -EOPNOTSUPP;
67 goto out_unlock;
68 } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) {
69 if (vi->xattr_isize) {
70 erofs_err(sb, "bogus xattr ibody @ nid %llu", vi->nid);
71 DBG_BUGON(1);
72 ret = -EFSCORRUPTED;
73 goto out_unlock; /* xattr ondisk layout error */
74 }
75 ret = -ENODATA;
76 goto out_unlock;
77 }
78
79 it.buf = __EROFS_BUF_INITIALIZER;
80 ret = erofs_init_metabuf(&it.buf, sb, erofs_inode_in_metabox(inode));
81 if (ret)
82 goto out_unlock;
83 it.pos = erofs_iloc(inode) + vi->inode_isize;
84
85 /* read in shared xattr array (non-atomic, see kmalloc below) */
86 it.kaddr = erofs_bread(&it.buf, it.pos, true);
87 if (IS_ERR(it.kaddr)) {
88 ret = PTR_ERR(it.kaddr);
89 goto out_unlock;
90 }
91
92 ih = it.kaddr;
93 vi->xattr_name_filter = le32_to_cpu(ih->h_name_filter);
94 vi->xattr_shared_count = ih->h_shared_count;
95 vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
96 sizeof(uint), GFP_KERNEL);
97 if (!vi->xattr_shared_xattrs) {
98 erofs_put_metabuf(&it.buf);
99 ret = -ENOMEM;
100 goto out_unlock;
101 }
102
103 /* let's skip ibody header */
104 it.pos += sizeof(struct erofs_xattr_ibody_header);
105
106 for (i = 0; i < vi->xattr_shared_count; ++i) {
107 it.kaddr = erofs_bread(&it.buf, it.pos, true);
108 if (IS_ERR(it.kaddr)) {
109 kfree(vi->xattr_shared_xattrs);
110 vi->xattr_shared_xattrs = NULL;
111 ret = PTR_ERR(it.kaddr);
112 goto out_unlock;
113 }
114 vi->xattr_shared_xattrs[i] = le32_to_cpu(*(__le32 *)it.kaddr);
115 it.pos += sizeof(__le32);
116 }
117 erofs_put_metabuf(&it.buf);
118
119 /* paired with smp_mb() at the beginning of the function. */
120 smp_mb();
121 set_bit(EROFS_I_EA_INITED_BIT, &vi->flags);
122
123 out_unlock:
124 clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);
125 return ret;
126 }
127
erofs_xattr_user_list(struct dentry * dentry)128 static bool erofs_xattr_user_list(struct dentry *dentry)
129 {
130 return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER);
131 }
132
erofs_xattr_trusted_list(struct dentry * dentry)133 static bool erofs_xattr_trusted_list(struct dentry *dentry)
134 {
135 return capable(CAP_SYS_ADMIN);
136 }
137
erofs_xattr_generic_get(const struct xattr_handler * handler,struct dentry * unused,struct inode * inode,const char * name,void * buffer,size_t size)138 static int erofs_xattr_generic_get(const struct xattr_handler *handler,
139 struct dentry *unused, struct inode *inode,
140 const char *name, void *buffer, size_t size)
141 {
142 if (handler->flags == EROFS_XATTR_INDEX_USER &&
143 !test_opt(&EROFS_I_SB(inode)->opt, XATTR_USER))
144 return -EOPNOTSUPP;
145
146 return erofs_getxattr(inode, handler->flags, name, buffer, size);
147 }
148
149 const struct xattr_handler erofs_xattr_user_handler = {
150 .prefix = XATTR_USER_PREFIX,
151 .flags = EROFS_XATTR_INDEX_USER,
152 .list = erofs_xattr_user_list,
153 .get = erofs_xattr_generic_get,
154 };
155
156 const struct xattr_handler erofs_xattr_trusted_handler = {
157 .prefix = XATTR_TRUSTED_PREFIX,
158 .flags = EROFS_XATTR_INDEX_TRUSTED,
159 .list = erofs_xattr_trusted_list,
160 .get = erofs_xattr_generic_get,
161 };
162
163 #ifdef CONFIG_EROFS_FS_SECURITY
164 const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
165 .prefix = XATTR_SECURITY_PREFIX,
166 .flags = EROFS_XATTR_INDEX_SECURITY,
167 .get = erofs_xattr_generic_get,
168 };
169 #endif
170
171 const struct xattr_handler * const erofs_xattr_handlers[] = {
172 &erofs_xattr_user_handler,
173 &erofs_xattr_trusted_handler,
174 #ifdef CONFIG_EROFS_FS_SECURITY
175 &erofs_xattr_security_handler,
176 #endif
177 NULL,
178 };
179
erofs_xattr_copy_to_buffer(struct erofs_xattr_iter * it,unsigned int len)180 static int erofs_xattr_copy_to_buffer(struct erofs_xattr_iter *it,
181 unsigned int len)
182 {
183 unsigned int slice, processed;
184 struct super_block *sb = it->sb;
185 void *src;
186
187 for (processed = 0; processed < len; processed += slice) {
188 it->kaddr = erofs_bread(&it->buf, it->pos, true);
189 if (IS_ERR(it->kaddr))
190 return PTR_ERR(it->kaddr);
191
192 src = it->kaddr;
193 slice = min_t(unsigned int, sb->s_blocksize -
194 erofs_blkoff(sb, it->pos), len - processed);
195 memcpy(it->buffer + it->buffer_ofs, src, slice);
196 it->buffer_ofs += slice;
197 it->pos += slice;
198 }
199 return 0;
200 }
201
erofs_listxattr_foreach(struct erofs_xattr_iter * it)202 static int erofs_listxattr_foreach(struct erofs_xattr_iter *it)
203 {
204 struct erofs_xattr_entry entry;
205 unsigned int base_index, name_total, prefix_len, infix_len = 0;
206 const char *prefix, *infix = NULL;
207 int err;
208
209 /* 1. handle xattr entry */
210 entry = *(struct erofs_xattr_entry *)it->kaddr;
211 it->pos += sizeof(struct erofs_xattr_entry);
212
213 base_index = entry.e_name_index;
214 if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
215 struct erofs_sb_info *sbi = EROFS_SB(it->sb);
216 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
217 (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
218
219 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
220 return 0;
221 infix = pf->prefix->infix;
222 infix_len = pf->infix_len;
223 base_index = pf->prefix->base_index;
224 }
225
226 prefix = erofs_xattr_prefix(base_index, it->dentry);
227 if (!prefix)
228 return 0;
229 prefix_len = strlen(prefix);
230 name_total = prefix_len + infix_len + entry.e_name_len + 1;
231
232 if (!it->buffer) {
233 it->buffer_ofs += name_total;
234 return 0;
235 }
236
237 if (it->buffer_ofs + name_total > it->buffer_size)
238 return -ERANGE;
239
240 memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
241 memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len);
242 it->buffer_ofs += prefix_len + infix_len;
243
244 /* 2. handle xattr name */
245 err = erofs_xattr_copy_to_buffer(it, entry.e_name_len);
246 if (err)
247 return err;
248
249 it->buffer[it->buffer_ofs++] = '\0';
250 return 0;
251 }
252
erofs_getxattr_foreach(struct erofs_xattr_iter * it)253 static int erofs_getxattr_foreach(struct erofs_xattr_iter *it)
254 {
255 struct super_block *sb = it->sb;
256 struct erofs_xattr_entry entry;
257 unsigned int slice, processed, value_sz;
258
259 /* 1. handle xattr entry */
260 entry = *(struct erofs_xattr_entry *)it->kaddr;
261 it->pos += sizeof(struct erofs_xattr_entry);
262 value_sz = le16_to_cpu(entry.e_value_size);
263
264 /* should also match the infix for long name prefixes */
265 if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
266 struct erofs_sb_info *sbi = EROFS_SB(sb);
267 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
268 (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
269
270 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
271 return -ENODATA;
272
273 if (it->index != pf->prefix->base_index ||
274 it->name.len != entry.e_name_len + pf->infix_len)
275 return -ENODATA;
276
277 if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len))
278 return -ENODATA;
279
280 it->infix_len = pf->infix_len;
281 } else {
282 if (it->index != entry.e_name_index ||
283 it->name.len != entry.e_name_len)
284 return -ENODATA;
285
286 it->infix_len = 0;
287 }
288
289 /* 2. handle xattr name */
290 for (processed = 0; processed < entry.e_name_len; processed += slice) {
291 it->kaddr = erofs_bread(&it->buf, it->pos, true);
292 if (IS_ERR(it->kaddr))
293 return PTR_ERR(it->kaddr);
294
295 slice = min_t(unsigned int,
296 sb->s_blocksize - erofs_blkoff(sb, it->pos),
297 entry.e_name_len - processed);
298 if (memcmp(it->name.name + it->infix_len + processed,
299 it->kaddr, slice))
300 return -ENODATA;
301 it->pos += slice;
302 }
303
304 /* 3. handle xattr value */
305 if (!it->buffer) {
306 it->buffer_ofs = value_sz;
307 return 0;
308 }
309
310 if (it->buffer_size < value_sz)
311 return -ERANGE;
312
313 return erofs_xattr_copy_to_buffer(it, value_sz);
314 }
315
erofs_xattr_iter_inline(struct erofs_xattr_iter * it,struct inode * inode,bool getxattr)316 static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it,
317 struct inode *inode, bool getxattr)
318 {
319 struct erofs_inode *const vi = EROFS_I(inode);
320 unsigned int xattr_header_sz, remaining, entry_sz;
321 erofs_off_t next_pos;
322 int ret;
323
324 xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) +
325 sizeof(u32) * vi->xattr_shared_count;
326 if (xattr_header_sz >= vi->xattr_isize) {
327 DBG_BUGON(xattr_header_sz > vi->xattr_isize);
328 return -ENODATA;
329 }
330
331 ret = erofs_init_metabuf(&it->buf, it->sb, erofs_inode_in_metabox(inode));
332 if (ret)
333 return ret;
334 remaining = vi->xattr_isize - xattr_header_sz;
335 it->pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz;
336
337 while (remaining) {
338 it->kaddr = erofs_bread(&it->buf, it->pos, true);
339 if (IS_ERR(it->kaddr))
340 return PTR_ERR(it->kaddr);
341
342 entry_sz = erofs_xattr_entry_size(it->kaddr);
343 /* xattr on-disk corruption: xattr entry beyond xattr_isize */
344 if (remaining < entry_sz) {
345 DBG_BUGON(1);
346 return -EFSCORRUPTED;
347 }
348 remaining -= entry_sz;
349 next_pos = it->pos + entry_sz;
350
351 if (getxattr)
352 ret = erofs_getxattr_foreach(it);
353 else
354 ret = erofs_listxattr_foreach(it);
355 if ((getxattr && ret != -ENODATA) || (!getxattr && ret))
356 break;
357
358 it->pos = next_pos;
359 }
360 return ret;
361 }
362
erofs_xattr_iter_shared(struct erofs_xattr_iter * it,struct inode * inode,bool getxattr)363 static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it,
364 struct inode *inode, bool getxattr)
365 {
366 struct erofs_inode *const vi = EROFS_I(inode);
367 struct super_block *const sb = it->sb;
368 struct erofs_sb_info *sbi = EROFS_SB(sb);
369 unsigned int i = 0;
370 int ret;
371
372 ret = erofs_init_metabuf(&it->buf, sb,
373 erofs_sb_has_shared_ea_in_metabox(sbi));
374 if (ret)
375 return ret;
376
377 while (i < vi->xattr_shared_count) {
378 it->pos = erofs_pos(sb, sbi->xattr_blkaddr) +
379 vi->xattr_shared_xattrs[i++] * sizeof(__le32);
380 it->kaddr = erofs_bread(&it->buf, it->pos, true);
381 if (IS_ERR(it->kaddr))
382 return PTR_ERR(it->kaddr);
383
384 if (getxattr)
385 ret = erofs_getxattr_foreach(it);
386 else
387 ret = erofs_listxattr_foreach(it);
388 if ((getxattr && ret != -ENODATA) || (!getxattr && ret))
389 break;
390 }
391 return i ? ret : -ENODATA;
392 }
393
erofs_getxattr(struct inode * inode,int index,const char * name,void * buffer,size_t buffer_size)394 int erofs_getxattr(struct inode *inode, int index, const char *name,
395 void *buffer, size_t buffer_size)
396 {
397 int ret;
398 unsigned int hashbit;
399 struct erofs_xattr_iter it;
400 struct erofs_inode *vi = EROFS_I(inode);
401 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
402
403 if (!name)
404 return -EINVAL;
405
406 ret = erofs_init_inode_xattrs(inode);
407 if (ret)
408 return ret;
409
410 /* reserved flag is non-zero if there's any change of on-disk format */
411 if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved) {
412 hashbit = xxh32(name, strlen(name),
413 EROFS_XATTR_FILTER_SEED + index);
414 hashbit &= EROFS_XATTR_FILTER_BITS - 1;
415 if (vi->xattr_name_filter & (1U << hashbit))
416 return -ENODATA;
417 }
418
419 it.index = index;
420 it.name = QSTR(name);
421 if (it.name.len > EROFS_NAME_LEN)
422 return -ERANGE;
423
424 it.sb = inode->i_sb;
425 it.buf = __EROFS_BUF_INITIALIZER;
426 it.buffer = buffer;
427 it.buffer_size = buffer_size;
428 it.buffer_ofs = 0;
429
430 ret = erofs_xattr_iter_inline(&it, inode, true);
431 if (ret == -ENODATA)
432 ret = erofs_xattr_iter_shared(&it, inode, true);
433 erofs_put_metabuf(&it.buf);
434 return ret ? ret : it.buffer_ofs;
435 }
436
erofs_listxattr(struct dentry * dentry,char * buffer,size_t buffer_size)437 ssize_t erofs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
438 {
439 int ret;
440 struct erofs_xattr_iter it;
441 struct inode *inode = d_inode(dentry);
442
443 ret = erofs_init_inode_xattrs(inode);
444 if (ret == -ENODATA)
445 return 0;
446 if (ret)
447 return ret;
448
449 it.sb = dentry->d_sb;
450 it.buf = __EROFS_BUF_INITIALIZER;
451 it.dentry = dentry;
452 it.buffer = buffer;
453 it.buffer_size = buffer_size;
454 it.buffer_ofs = 0;
455
456 ret = erofs_xattr_iter_inline(&it, inode, false);
457 if (!ret || ret == -ENODATA)
458 ret = erofs_xattr_iter_shared(&it, inode, false);
459 if (ret == -ENODATA)
460 ret = 0;
461 erofs_put_metabuf(&it.buf);
462 return ret ? ret : it.buffer_ofs;
463 }
464
erofs_xattr_prefixes_cleanup(struct super_block * sb)465 void erofs_xattr_prefixes_cleanup(struct super_block *sb)
466 {
467 struct erofs_sb_info *sbi = EROFS_SB(sb);
468 int i;
469
470 if (sbi->xattr_prefixes) {
471 for (i = 0; i < sbi->xattr_prefix_count; i++)
472 kfree(sbi->xattr_prefixes[i].prefix);
473 kfree(sbi->xattr_prefixes);
474 sbi->xattr_prefixes = NULL;
475 }
476 }
477
erofs_xattr_prefixes_init(struct super_block * sb)478 int erofs_xattr_prefixes_init(struct super_block *sb)
479 {
480 struct erofs_sb_info *sbi = EROFS_SB(sb);
481 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
482 erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2;
483 struct erofs_xattr_prefix_item *pfs;
484 int ret = 0, i, len;
485
486 if (!sbi->xattr_prefix_count)
487 return 0;
488
489 pfs = kcalloc(sbi->xattr_prefix_count, sizeof(*pfs), GFP_KERNEL);
490 if (!pfs)
491 return -ENOMEM;
492
493 if (sbi->packed_inode)
494 buf.mapping = sbi->packed_inode->i_mapping;
495 else
496 (void)erofs_init_metabuf(&buf, sb, false);
497
498 for (i = 0; i < sbi->xattr_prefix_count; i++) {
499 void *ptr = erofs_read_metadata(sb, &buf, &pos, &len);
500
501 if (IS_ERR(ptr)) {
502 ret = PTR_ERR(ptr);
503 break;
504 } else if (len < sizeof(*pfs->prefix) ||
505 len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) {
506 kfree(ptr);
507 ret = -EFSCORRUPTED;
508 break;
509 }
510 pfs[i].prefix = ptr;
511 pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix);
512 }
513
514 erofs_put_metabuf(&buf);
515 sbi->xattr_prefixes = pfs;
516 if (ret)
517 erofs_xattr_prefixes_cleanup(sb);
518 return ret;
519 }
520
521 #ifdef CONFIG_EROFS_FS_POSIX_ACL
erofs_get_acl(struct inode * inode,int type,bool rcu)522 struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu)
523 {
524 struct posix_acl *acl;
525 int prefix, rc;
526 char *value = NULL;
527
528 if (rcu)
529 return ERR_PTR(-ECHILD);
530
531 switch (type) {
532 case ACL_TYPE_ACCESS:
533 prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
534 break;
535 case ACL_TYPE_DEFAULT:
536 prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
537 break;
538 default:
539 return ERR_PTR(-EINVAL);
540 }
541
542 rc = erofs_getxattr(inode, prefix, "", NULL, 0);
543 if (rc > 0) {
544 value = kmalloc(rc, GFP_KERNEL);
545 if (!value)
546 return ERR_PTR(-ENOMEM);
547 rc = erofs_getxattr(inode, prefix, "", value, rc);
548 }
549
550 if (rc == -ENODATA)
551 acl = NULL;
552 else if (rc < 0)
553 acl = ERR_PTR(rc);
554 else
555 acl = posix_acl_from_xattr(&init_user_ns, value, rc);
556 kfree(value);
557 return acl;
558 }
559 #endif
560