1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Created by Gao Xiang <gaoxiang25@huawei.com>
7 #include <linux/security.h>
11 struct super_block *sb;
19 static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
21 /* the only user of kunmap() is 'init_inode_xattrs' */
25 kunmap_atomic(it->kaddr);
27 unlock_page(it->page);
31 static inline void xattr_iter_end_final(struct xattr_iter *it)
36 xattr_iter_end(it, true);
39 static int init_inode_xattrs(struct inode *inode)
41 struct erofs_inode *const vi = EROFS_I(inode);
44 struct erofs_xattr_ibody_header *ih;
45 struct super_block *sb;
46 struct erofs_sb_info *sbi;
50 /* the most case is that xattrs of this inode are initialized. */
51 if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
54 if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE))
57 /* someone has initialized xattrs for us? */
58 if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
62 * bypass all xattr operations if ->xattr_isize is not greater than
63 * sizeof(struct erofs_xattr_ibody_header), in detail:
64 * 1) it is not enough to contain erofs_xattr_ibody_header then
65 * ->xattr_isize should be 0 (it means no xattr);
66 * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk
67 * undefined right now (maybe use later with some new sb feature).
69 if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) {
70 erofs_err(inode->i_sb,
71 "xattr_isize %d of nid %llu is not supported yet",
72 vi->xattr_isize, vi->nid);
75 } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) {
76 if (vi->xattr_isize) {
77 erofs_err(inode->i_sb,
78 "bogus xattr ibody @ nid %llu", vi->nid);
81 goto out_unlock; /* xattr ondisk layout error */
89 it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
90 it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
92 it.page = erofs_get_meta_page(sb, it.blkaddr);
93 if (IS_ERR(it.page)) {
94 ret = PTR_ERR(it.page);
98 /* read in shared xattr array (non-atomic, see kmalloc below) */
99 it.kaddr = kmap(it.page);
102 ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
104 vi->xattr_shared_count = ih->h_shared_count;
105 vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
106 sizeof(uint), GFP_KERNEL);
107 if (!vi->xattr_shared_xattrs) {
108 xattr_iter_end(&it, atomic_map);
113 /* let's skip ibody header */
114 it.ofs += sizeof(struct erofs_xattr_ibody_header);
116 for (i = 0; i < vi->xattr_shared_count; ++i) {
117 if (it.ofs >= EROFS_BLKSIZ) {
118 /* cannot be unaligned */
119 DBG_BUGON(it.ofs != EROFS_BLKSIZ);
120 xattr_iter_end(&it, atomic_map);
122 it.page = erofs_get_meta_page(sb, ++it.blkaddr);
123 if (IS_ERR(it.page)) {
124 kfree(vi->xattr_shared_xattrs);
125 vi->xattr_shared_xattrs = NULL;
126 ret = PTR_ERR(it.page);
130 it.kaddr = kmap_atomic(it.page);
134 vi->xattr_shared_xattrs[i] =
135 le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
136 it.ofs += sizeof(__le32);
138 xattr_iter_end(&it, atomic_map);
140 set_bit(EROFS_I_EA_INITED_BIT, &vi->flags);
143 clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);
148 * the general idea for these return values is
149 * if 0 is returned, go on processing the current xattr;
150 * 1 (> 0) is returned, skip this round to process the next xattr;
151 * -err (< 0) is returned, an error (maybe ENOXATTR) occurred
152 * and need to be handled
154 struct xattr_iter_handlers {
155 int (*entry)(struct xattr_iter *_it, struct erofs_xattr_entry *entry);
156 int (*name)(struct xattr_iter *_it, unsigned int processed, char *buf,
158 int (*alloc_buffer)(struct xattr_iter *_it, unsigned int value_sz);
159 void (*value)(struct xattr_iter *_it, unsigned int processed, char *buf,
163 static inline int xattr_iter_fixup(struct xattr_iter *it)
165 if (it->ofs < EROFS_BLKSIZ)
168 xattr_iter_end(it, true);
170 it->blkaddr += erofs_blknr(it->ofs);
172 it->page = erofs_get_meta_page(it->sb, it->blkaddr);
173 if (IS_ERR(it->page)) {
174 int err = PTR_ERR(it->page);
180 it->kaddr = kmap_atomic(it->page);
181 it->ofs = erofs_blkoff(it->ofs);
185 static int inline_xattr_iter_begin(struct xattr_iter *it,
188 struct erofs_inode *const vi = EROFS_I(inode);
189 struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
190 unsigned int xattr_header_sz, inline_xattr_ofs;
192 xattr_header_sz = inlinexattr_header_size(inode);
193 if (xattr_header_sz >= vi->xattr_isize) {
194 DBG_BUGON(xattr_header_sz > vi->xattr_isize);
198 inline_xattr_ofs = vi->inode_isize + xattr_header_sz;
200 it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
201 it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
203 it->page = erofs_get_meta_page(inode->i_sb, it->blkaddr);
204 if (IS_ERR(it->page))
205 return PTR_ERR(it->page);
207 it->kaddr = kmap_atomic(it->page);
208 return vi->xattr_isize - xattr_header_sz;
212 * Regardless of success or failure, `xattr_foreach' will end up with
213 * `ofs' pointing to the next xattr item rather than an arbitrary position.
215 static int xattr_foreach(struct xattr_iter *it,
216 const struct xattr_iter_handlers *op,
217 unsigned int *tlimit)
219 struct erofs_xattr_entry entry;
220 unsigned int value_sz, processed, slice;
223 /* 0. fixup blkaddr, ofs, ipage */
224 err = xattr_iter_fixup(it);
229 * 1. read xattr entry to the memory,
230 * since we do EROFS_XATTR_ALIGN
231 * therefore entry should be in the page
233 entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
235 unsigned int entry_sz = erofs_xattr_entry_size(&entry);
237 /* xattr on-disk corruption: xattr entry beyond xattr_isize */
238 if (*tlimit < entry_sz) {
240 return -EFSCORRUPTED;
245 it->ofs += sizeof(struct erofs_xattr_entry);
246 value_sz = le16_to_cpu(entry.e_value_size);
249 err = op->entry(it, &entry);
251 it->ofs += entry.e_name_len + value_sz;
255 /* 2. handle xattr name (ofs will finally be at the end of name) */
258 while (processed < entry.e_name_len) {
259 if (it->ofs >= EROFS_BLKSIZ) {
260 DBG_BUGON(it->ofs > EROFS_BLKSIZ);
262 err = xattr_iter_fixup(it);
268 slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
269 entry.e_name_len - processed);
272 err = op->name(it, processed, it->kaddr + it->ofs, slice);
274 it->ofs += entry.e_name_len - processed + value_sz;
282 /* 3. handle xattr value */
285 if (op->alloc_buffer) {
286 err = op->alloc_buffer(it, value_sz);
293 while (processed < value_sz) {
294 if (it->ofs >= EROFS_BLKSIZ) {
295 DBG_BUGON(it->ofs > EROFS_BLKSIZ);
297 err = xattr_iter_fixup(it);
303 slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
304 value_sz - processed);
305 op->value(it, processed, it->kaddr + it->ofs, slice);
311 /* xattrs should be 4-byte aligned (on-disk constraint) */
312 it->ofs = EROFS_XATTR_ALIGN(it->ofs);
313 return err < 0 ? err : 0;
316 struct getxattr_iter {
317 struct xattr_iter it;
320 int buffer_size, index;
324 static int xattr_entrymatch(struct xattr_iter *_it,
325 struct erofs_xattr_entry *entry)
327 struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
329 return (it->index != entry->e_name_index ||
330 it->name.len != entry->e_name_len) ? -ENOATTR : 0;
333 static int xattr_namematch(struct xattr_iter *_it,
334 unsigned int processed, char *buf, unsigned int len)
336 struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
338 return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;
341 static int xattr_checkbuffer(struct xattr_iter *_it,
342 unsigned int value_sz)
344 struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
345 int err = it->buffer_size < value_sz ? -ERANGE : 0;
347 it->buffer_size = value_sz;
348 return !it->buffer ? 1 : err;
351 static void xattr_copyvalue(struct xattr_iter *_it,
352 unsigned int processed,
353 char *buf, unsigned int len)
355 struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
357 memcpy(it->buffer + processed, buf, len);
360 static const struct xattr_iter_handlers find_xattr_handlers = {
361 .entry = xattr_entrymatch,
362 .name = xattr_namematch,
363 .alloc_buffer = xattr_checkbuffer,
364 .value = xattr_copyvalue
367 static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
370 unsigned int remaining;
372 ret = inline_xattr_iter_begin(&it->it, inode);
378 ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining);
382 xattr_iter_end_final(&it->it);
384 return ret ? ret : it->buffer_size;
387 static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
389 struct erofs_inode *const vi = EROFS_I(inode);
390 struct super_block *const sb = inode->i_sb;
391 struct erofs_sb_info *const sbi = EROFS_SB(sb);
395 for (i = 0; i < vi->xattr_shared_count; ++i) {
396 erofs_blk_t blkaddr =
397 xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
399 it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
401 if (!i || blkaddr != it->it.blkaddr) {
403 xattr_iter_end(&it->it, true);
405 it->it.page = erofs_get_meta_page(sb, blkaddr);
406 if (IS_ERR(it->it.page))
407 return PTR_ERR(it->it.page);
409 it->it.kaddr = kmap_atomic(it->it.page);
410 it->it.blkaddr = blkaddr;
413 ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL);
417 if (vi->xattr_shared_count)
418 xattr_iter_end_final(&it->it);
420 return ret ? ret : it->buffer_size;
423 static bool erofs_xattr_user_list(struct dentry *dentry)
425 return test_opt(&EROFS_SB(dentry->d_sb)->ctx, XATTR_USER);
428 static bool erofs_xattr_trusted_list(struct dentry *dentry)
430 return capable(CAP_SYS_ADMIN);
433 int erofs_getxattr(struct inode *inode, int index,
435 void *buffer, size_t buffer_size)
438 struct getxattr_iter it;
443 ret = init_inode_xattrs(inode);
449 it.name.len = strlen(name);
450 if (it.name.len > EROFS_NAME_LEN)
455 it.buffer_size = buffer_size;
457 it.it.sb = inode->i_sb;
458 ret = inline_getxattr(inode, &it);
460 ret = shared_getxattr(inode, &it);
464 static int erofs_xattr_generic_get(const struct xattr_handler *handler,
465 struct dentry *unused, struct inode *inode,
466 const char *name, void *buffer, size_t size)
468 struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
470 switch (handler->flags) {
471 case EROFS_XATTR_INDEX_USER:
472 if (!test_opt(&sbi->ctx, XATTR_USER))
475 case EROFS_XATTR_INDEX_TRUSTED:
477 case EROFS_XATTR_INDEX_SECURITY:
483 return erofs_getxattr(inode, handler->flags, name, buffer, size);
486 const struct xattr_handler erofs_xattr_user_handler = {
487 .prefix = XATTR_USER_PREFIX,
488 .flags = EROFS_XATTR_INDEX_USER,
489 .list = erofs_xattr_user_list,
490 .get = erofs_xattr_generic_get,
493 const struct xattr_handler erofs_xattr_trusted_handler = {
494 .prefix = XATTR_TRUSTED_PREFIX,
495 .flags = EROFS_XATTR_INDEX_TRUSTED,
496 .list = erofs_xattr_trusted_list,
497 .get = erofs_xattr_generic_get,
500 #ifdef CONFIG_EROFS_FS_SECURITY
501 const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
502 .prefix = XATTR_SECURITY_PREFIX,
503 .flags = EROFS_XATTR_INDEX_SECURITY,
504 .get = erofs_xattr_generic_get,
508 const struct xattr_handler *erofs_xattr_handlers[] = {
509 &erofs_xattr_user_handler,
510 #ifdef CONFIG_EROFS_FS_POSIX_ACL
511 &posix_acl_access_xattr_handler,
512 &posix_acl_default_xattr_handler,
514 &erofs_xattr_trusted_handler,
515 #ifdef CONFIG_EROFS_FS_SECURITY
516 &erofs_xattr_security_handler,
521 struct listxattr_iter {
522 struct xattr_iter it;
524 struct dentry *dentry;
526 int buffer_size, buffer_ofs;
529 static int xattr_entrylist(struct xattr_iter *_it,
530 struct erofs_xattr_entry *entry)
532 struct listxattr_iter *it =
533 container_of(_it, struct listxattr_iter, it);
534 unsigned int prefix_len;
537 const struct xattr_handler *h =
538 erofs_xattr_handler(entry->e_name_index);
540 if (!h || (h->list && !h->list(it->dentry)))
543 prefix = xattr_prefix(h);
544 prefix_len = strlen(prefix);
547 it->buffer_ofs += prefix_len + entry->e_name_len + 1;
551 if (it->buffer_ofs + prefix_len
552 + entry->e_name_len + 1 > it->buffer_size)
555 memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
556 it->buffer_ofs += prefix_len;
560 static int xattr_namelist(struct xattr_iter *_it,
561 unsigned int processed, char *buf, unsigned int len)
563 struct listxattr_iter *it =
564 container_of(_it, struct listxattr_iter, it);
566 memcpy(it->buffer + it->buffer_ofs, buf, len);
567 it->buffer_ofs += len;
571 static int xattr_skipvalue(struct xattr_iter *_it,
572 unsigned int value_sz)
574 struct listxattr_iter *it =
575 container_of(_it, struct listxattr_iter, it);
577 it->buffer[it->buffer_ofs++] = '\0';
581 static const struct xattr_iter_handlers list_xattr_handlers = {
582 .entry = xattr_entrylist,
583 .name = xattr_namelist,
584 .alloc_buffer = xattr_skipvalue,
588 static int inline_listxattr(struct listxattr_iter *it)
591 unsigned int remaining;
593 ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry));
599 ret = xattr_foreach(&it->it, &list_xattr_handlers, &remaining);
603 xattr_iter_end_final(&it->it);
604 return ret ? ret : it->buffer_ofs;
607 static int shared_listxattr(struct listxattr_iter *it)
609 struct inode *const inode = d_inode(it->dentry);
610 struct erofs_inode *const vi = EROFS_I(inode);
611 struct super_block *const sb = inode->i_sb;
612 struct erofs_sb_info *const sbi = EROFS_SB(sb);
616 for (i = 0; i < vi->xattr_shared_count; ++i) {
617 erofs_blk_t blkaddr =
618 xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
620 it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
621 if (!i || blkaddr != it->it.blkaddr) {
623 xattr_iter_end(&it->it, true);
625 it->it.page = erofs_get_meta_page(sb, blkaddr);
626 if (IS_ERR(it->it.page))
627 return PTR_ERR(it->it.page);
629 it->it.kaddr = kmap_atomic(it->it.page);
630 it->it.blkaddr = blkaddr;
633 ret = xattr_foreach(&it->it, &list_xattr_handlers, NULL);
637 if (vi->xattr_shared_count)
638 xattr_iter_end_final(&it->it);
640 return ret ? ret : it->buffer_ofs;
643 ssize_t erofs_listxattr(struct dentry *dentry,
644 char *buffer, size_t buffer_size)
647 struct listxattr_iter it;
649 ret = init_inode_xattrs(d_inode(dentry));
657 it.buffer_size = buffer_size;
660 it.it.sb = dentry->d_sb;
662 ret = inline_listxattr(&it);
663 if (ret < 0 && ret != -ENOATTR)
665 return shared_listxattr(&it);
668 #ifdef CONFIG_EROFS_FS_POSIX_ACL
669 struct posix_acl *erofs_get_acl(struct inode *inode, int type)
671 struct posix_acl *acl;
676 case ACL_TYPE_ACCESS:
677 prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
679 case ACL_TYPE_DEFAULT:
680 prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
683 return ERR_PTR(-EINVAL);
686 rc = erofs_getxattr(inode, prefix, "", NULL, 0);
688 value = kmalloc(rc, GFP_KERNEL);
690 return ERR_PTR(-ENOMEM);
691 rc = erofs_getxattr(inode, prefix, "", value, rc);
699 acl = posix_acl_from_xattr(&init_user_ns, value, rc);