1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org>
5 * Fixes from William Schumacher incorporated on 15 March 2001.
6 * (Reported by Charles Bertsch, <CBertsch@microtest.com>).
10 * This file contains generic functions for manipulating
11 * POSIX 1003.1e draft standard 17 ACLs.
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/atomic.h>
18 #include <linux/sched.h>
19 #include <linux/cred.h>
20 #include <linux/posix_acl.h>
21 #include <linux/posix_acl_xattr.h>
22 #include <linux/xattr.h>
23 #include <linux/export.h>
24 #include <linux/user_namespace.h>
25 #include <linux/namei.h>
26 #include <linux/mnt_idmapping.h>
27 #include <linux/iversion.h>
28 #include <linux/security.h>
29 #include <linux/evm.h>
30 #include <linux/fsnotify.h>
34 static struct posix_acl **acl_by_type(struct inode *inode, int type)
39 case ACL_TYPE_DEFAULT:
40 return &inode->i_default_acl;
46 struct posix_acl *get_cached_acl(struct inode *inode, int type)
48 struct posix_acl **p = acl_by_type(inode, type);
49 struct posix_acl *acl;
53 acl = rcu_dereference(*p);
54 if (!acl || is_uncached_acl(acl) ||
55 refcount_inc_not_zero(&acl->a_refcount))
63 EXPORT_SYMBOL(get_cached_acl);
65 struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
67 struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type));
69 if (acl == ACL_DONT_CACHE) {
70 struct posix_acl *ret;
72 ret = inode->i_op->get_inode_acl(inode, type, LOOKUP_RCU);
79 EXPORT_SYMBOL(get_cached_acl_rcu);
81 void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
83 struct posix_acl **p = acl_by_type(inode, type);
84 struct posix_acl *old;
86 old = xchg(p, posix_acl_dup(acl));
87 if (!is_uncached_acl(old))
88 posix_acl_release(old);
90 EXPORT_SYMBOL(set_cached_acl);
92 static void __forget_cached_acl(struct posix_acl **p)
94 struct posix_acl *old;
96 old = xchg(p, ACL_NOT_CACHED);
97 if (!is_uncached_acl(old))
98 posix_acl_release(old);
101 void forget_cached_acl(struct inode *inode, int type)
103 __forget_cached_acl(acl_by_type(inode, type));
105 EXPORT_SYMBOL(forget_cached_acl);
107 void forget_all_cached_acls(struct inode *inode)
109 __forget_cached_acl(&inode->i_acl);
110 __forget_cached_acl(&inode->i_default_acl);
112 EXPORT_SYMBOL(forget_all_cached_acls);
114 static struct posix_acl *__get_acl(struct mnt_idmap *idmap,
115 struct dentry *dentry, struct inode *inode,
118 struct posix_acl *sentinel;
119 struct posix_acl **p;
120 struct posix_acl *acl;
123 * The sentinel is used to detect when another operation like
124 * set_cached_acl() or forget_cached_acl() races with get_inode_acl().
125 * It is guaranteed that is_uncached_acl(sentinel) is true.
128 acl = get_cached_acl(inode, type);
129 if (!is_uncached_acl(acl))
132 if (!IS_POSIXACL(inode))
135 sentinel = uncached_acl_sentinel(current);
136 p = acl_by_type(inode, type);
139 * If the ACL isn't being read yet, set our sentinel. Otherwise, the
140 * current value of the ACL will not be ACL_NOT_CACHED and so our own
141 * sentinel will not be set; another task will update the cache. We
142 * could wait for that other task to complete its job, but it's easier
143 * to just call ->get_inode_acl to fetch the ACL ourself. (This is
144 * going to be an unlikely race.)
146 cmpxchg(p, ACL_NOT_CACHED, sentinel);
149 * Normally, the ACL returned by ->get{_inode}_acl will be cached.
150 * A filesystem can prevent that by calling
151 * forget_cached_acl(inode, type) in ->get{_inode}_acl.
153 * If the filesystem doesn't have a get{_inode}_ acl() function at all,
154 * we'll just create the negative cache entry.
156 if (dentry && inode->i_op->get_acl) {
157 acl = inode->i_op->get_acl(idmap, dentry, type);
158 } else if (inode->i_op->get_inode_acl) {
159 acl = inode->i_op->get_inode_acl(inode, type, false);
161 set_cached_acl(inode, type, NULL);
166 * Remove our sentinel so that we don't block future attempts
169 cmpxchg(p, sentinel, ACL_NOT_CACHED);
174 * Cache the result, but only if our sentinel is still in place.
177 if (unlikely(cmpxchg(p, sentinel, acl) != sentinel))
178 posix_acl_release(acl);
182 struct posix_acl *get_inode_acl(struct inode *inode, int type)
184 return __get_acl(&nop_mnt_idmap, NULL, inode, type);
186 EXPORT_SYMBOL(get_inode_acl);
189 * Init a fresh posix_acl
192 posix_acl_init(struct posix_acl *acl, int count)
194 refcount_set(&acl->a_refcount, 1);
195 acl->a_count = count;
197 EXPORT_SYMBOL(posix_acl_init);
200 * Allocate a new ACL with the specified number of entries.
203 posix_acl_alloc(int count, gfp_t flags)
205 const size_t size = sizeof(struct posix_acl) +
206 count * sizeof(struct posix_acl_entry);
207 struct posix_acl *acl = kmalloc(size, flags);
209 posix_acl_init(acl, count);
212 EXPORT_SYMBOL(posix_acl_alloc);
218 posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
220 struct posix_acl *clone = NULL;
223 int size = sizeof(struct posix_acl) + acl->a_count *
224 sizeof(struct posix_acl_entry);
225 clone = kmemdup(acl, size, flags);
227 refcount_set(&clone->a_refcount, 1);
231 EXPORT_SYMBOL_GPL(posix_acl_clone);
234 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
237 posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
239 const struct posix_acl_entry *pa, *pe;
240 int state = ACL_USER_OBJ;
243 FOREACH_ACL_ENTRY(pa, acl, pe) {
244 if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
248 if (state == ACL_USER_OBJ) {
255 if (state != ACL_USER)
257 if (!kuid_has_mapping(user_ns, pa->e_uid))
263 if (state == ACL_USER) {
270 if (state != ACL_GROUP)
272 if (!kgid_has_mapping(user_ns, pa->e_gid))
278 if (state != ACL_GROUP)
284 if (state == ACL_OTHER ||
285 (state == ACL_GROUP && !needs_mask)) {
299 EXPORT_SYMBOL(posix_acl_valid);
302 * Returns 0 if the acl can be exactly represented in the traditional
303 * file mode permission bits, or else 1. Returns -E... on error.
306 posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
308 const struct posix_acl_entry *pa, *pe;
313 * A null ACL can always be presented as mode bits.
318 FOREACH_ACL_ENTRY(pa, acl, pe) {
321 mode |= (pa->e_perm & S_IRWXO) << 6;
324 mode |= (pa->e_perm & S_IRWXO) << 3;
327 mode |= pa->e_perm & S_IRWXO;
330 mode = (mode & ~S_IRWXG) |
331 ((pa->e_perm & S_IRWXO) << 3);
343 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
346 EXPORT_SYMBOL(posix_acl_equiv_mode);
349 * Create an ACL representing the file mode permission bits of an inode.
352 posix_acl_from_mode(umode_t mode, gfp_t flags)
354 struct posix_acl *acl = posix_acl_alloc(3, flags);
356 return ERR_PTR(-ENOMEM);
358 acl->a_entries[0].e_tag = ACL_USER_OBJ;
359 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
361 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
362 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
364 acl->a_entries[2].e_tag = ACL_OTHER;
365 acl->a_entries[2].e_perm = (mode & S_IRWXO);
368 EXPORT_SYMBOL(posix_acl_from_mode);
371 * Return 0 if current is granted want access to the inode
372 * by the acl. Returns -E... otherwise.
375 posix_acl_permission(struct mnt_idmap *idmap, struct inode *inode,
376 const struct posix_acl *acl, int want)
378 const struct posix_acl_entry *pa, *pe, *mask_obj;
379 struct user_namespace *fs_userns = i_user_ns(inode);
380 struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
385 want &= MAY_READ | MAY_WRITE | MAY_EXEC;
387 FOREACH_ACL_ENTRY(pa, acl, pe) {
390 /* (May have been checked already) */
391 vfsuid = i_uid_into_vfsuid(mnt_userns, inode);
392 if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
396 vfsuid = make_vfsuid(mnt_userns, fs_userns,
398 if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
402 vfsgid = i_gid_into_vfsgid(mnt_userns, inode);
403 if (vfsgid_in_group_p(vfsgid)) {
405 if ((pa->e_perm & want) == want)
410 vfsgid = make_vfsgid(mnt_userns, fs_userns,
412 if (vfsgid_in_group_p(vfsgid)) {
414 if ((pa->e_perm & want) == want)
432 for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
433 if (mask_obj->e_tag == ACL_MASK) {
434 if ((pa->e_perm & mask_obj->e_perm & want) == want)
441 if ((pa->e_perm & want) == want)
447 * Modify acl when creating a new inode. The caller must ensure the acl is
448 * only referenced once.
450 * mode_p initially must contain the mode parameter to the open() / creat()
451 * system calls. All permissions that are not granted by the acl are removed.
452 * The permissions in the acl are changed to reflect the mode_p parameter.
454 static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
456 struct posix_acl_entry *pa, *pe;
457 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
458 umode_t mode = *mode_p;
461 /* assert(atomic_read(acl->a_refcount) == 1); */
463 FOREACH_ACL_ENTRY(pa, acl, pe) {
466 pa->e_perm &= (mode >> 6) | ~S_IRWXO;
467 mode &= (pa->e_perm << 6) | ~S_IRWXU;
480 pa->e_perm &= mode | ~S_IRWXO;
481 mode &= pa->e_perm | ~S_IRWXO;
495 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
496 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
500 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
501 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
504 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
509 * Modify the ACL for the chmod syscall.
511 static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
513 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
514 struct posix_acl_entry *pa, *pe;
516 /* assert(atomic_read(acl->a_refcount) == 1); */
518 FOREACH_ACL_ENTRY(pa, acl, pe) {
521 pa->e_perm = (mode & S_IRWXU) >> 6;
537 pa->e_perm = (mode & S_IRWXO);
546 mask_obj->e_perm = (mode & S_IRWXG) >> 3;
550 group_obj->e_perm = (mode & S_IRWXG) >> 3;
557 __posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
559 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
562 err = posix_acl_create_masq(clone, mode_p);
564 posix_acl_release(clone);
568 posix_acl_release(*acl);
572 EXPORT_SYMBOL(__posix_acl_create);
575 __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
577 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
580 err = __posix_acl_chmod_masq(clone, mode);
582 posix_acl_release(clone);
586 posix_acl_release(*acl);
590 EXPORT_SYMBOL(__posix_acl_chmod);
593 * posix_acl_chmod - chmod a posix acl
595 * @idmap: idmap of the mount @inode was found from
596 * @dentry: dentry to check permissions on
597 * @mode: the new mode of @inode
599 * If the dentry has been found through an idmapped mount the idmap of
600 * the vfsmount must be passed through @idmap. This function will then
601 * take care to map the inode according to @idmap before checking
602 * permissions. On non-idmapped mounts or if permission checking is to be
603 * performed on the raw inode simply passs @nop_mnt_idmap.
606 posix_acl_chmod(struct mnt_idmap *idmap, struct dentry *dentry,
609 struct inode *inode = d_inode(dentry);
610 struct posix_acl *acl;
613 if (!IS_POSIXACL(inode))
615 if (!inode->i_op->set_acl)
618 acl = get_inode_acl(inode, ACL_TYPE_ACCESS);
619 if (IS_ERR_OR_NULL(acl)) {
620 if (acl == ERR_PTR(-EOPNOTSUPP))
625 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
628 ret = inode->i_op->set_acl(idmap, dentry, acl, ACL_TYPE_ACCESS);
629 posix_acl_release(acl);
632 EXPORT_SYMBOL(posix_acl_chmod);
635 posix_acl_create(struct inode *dir, umode_t *mode,
636 struct posix_acl **default_acl, struct posix_acl **acl)
639 struct posix_acl *clone;
645 if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
648 p = get_inode_acl(dir, ACL_TYPE_DEFAULT);
649 if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
650 *mode &= ~current_umask();
657 clone = posix_acl_clone(p, GFP_NOFS);
661 ret = posix_acl_create_masq(clone, mode);
663 goto err_release_clone;
666 posix_acl_release(clone);
671 posix_acl_release(p);
678 posix_acl_release(clone);
680 posix_acl_release(p);
683 EXPORT_SYMBOL_GPL(posix_acl_create);
686 * posix_acl_update_mode - update mode in set_acl
687 * @idmap: idmap of the mount @inode was found from
688 * @inode: target inode
689 * @mode_p: mode (pointer) for update
692 * Update the file mode when setting an ACL: compute the new file permission
693 * bits based on the ACL. In addition, if the ACL is equivalent to the new
694 * file mode, set *@acl to NULL to indicate that no ACL should be set.
696 * As with chmod, clear the setgid bit if the caller is not in the owning group
697 * or capable of CAP_FSETID (see inode_change_ok).
699 * If the inode has been found through an idmapped mount the idmap of
700 * the vfsmount must be passed through @idmap. This function will then
701 * take care to map the inode according to @idmap before checking
702 * permissions. On non-idmapped mounts or if permission checking is to be
703 * performed on the raw inode simply passs @nop_mnt_idmap.
705 * Called from set_acl inode operations.
707 int posix_acl_update_mode(struct mnt_idmap *idmap,
708 struct inode *inode, umode_t *mode_p,
709 struct posix_acl **acl)
711 struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
712 umode_t mode = inode->i_mode;
715 error = posix_acl_equiv_mode(*acl, &mode);
720 if (!vfsgid_in_group_p(i_gid_into_vfsgid(mnt_userns, inode)) &&
721 !capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID))
726 EXPORT_SYMBOL(posix_acl_update_mode);
729 * Fix up the uids and gids in posix acl extended attributes in place.
731 static int posix_acl_fix_xattr_common(const void *value, size_t size)
733 const struct posix_acl_xattr_header *header = value;
738 if (size < sizeof(struct posix_acl_xattr_header))
740 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
743 count = posix_acl_xattr_count(size);
753 * posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format
754 * @userns: the filesystem's idmapping
755 * @value: the uapi representation of POSIX ACLs
756 * @size: the size of @void
758 * Filesystems that store POSIX ACLs in the unaltered uapi format should use
759 * posix_acl_from_xattr() when reading them from the backing store and
760 * converting them into the struct posix_acl VFS format. The helper is
761 * specifically intended to be called from the acl inode operation.
763 * The posix_acl_from_xattr() function will map the raw {g,u}id values stored
764 * in ACL_{GROUP,USER} entries into idmapping in @userns.
766 * Note that posix_acl_from_xattr() does not take idmapped mounts into account.
767 * If it did it calling it from the get acl inode operation would return POSIX
768 * ACLs mapped according to an idmapped mount which would mean that the value
769 * couldn't be cached for the filesystem. Idmapped mounts are taken into
770 * account on the fly during permission checking or right at the VFS -
771 * userspace boundary before reporting them to the user.
773 * Return: Allocated struct posix_acl on success, NULL for a valid header but
774 * without actual POSIX ACL entries, or ERR_PTR() encoded error code.
776 struct posix_acl *posix_acl_from_xattr(struct user_namespace *userns,
777 const void *value, size_t size)
779 const struct posix_acl_xattr_header *header = value;
780 const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
782 struct posix_acl *acl;
783 struct posix_acl_entry *acl_e;
785 count = posix_acl_fix_xattr_common(value, size);
787 return ERR_PTR(count);
791 acl = posix_acl_alloc(count, GFP_NOFS);
793 return ERR_PTR(-ENOMEM);
794 acl_e = acl->a_entries;
796 for (end = entry + count; entry != end; acl_e++, entry++) {
797 acl_e->e_tag = le16_to_cpu(entry->e_tag);
798 acl_e->e_perm = le16_to_cpu(entry->e_perm);
800 switch(acl_e->e_tag) {
808 acl_e->e_uid = make_kuid(userns,
809 le32_to_cpu(entry->e_id));
810 if (!uid_valid(acl_e->e_uid))
814 acl_e->e_gid = make_kgid(userns,
815 le32_to_cpu(entry->e_id));
816 if (!gid_valid(acl_e->e_gid))
827 posix_acl_release(acl);
828 return ERR_PTR(-EINVAL);
830 EXPORT_SYMBOL (posix_acl_from_xattr);
833 * Convert from in-memory to extended attribute representation.
836 posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
837 void *buffer, size_t size)
839 struct posix_acl_xattr_header *ext_acl = buffer;
840 struct posix_acl_xattr_entry *ext_entry;
843 real_size = posix_acl_xattr_size(acl->a_count);
846 if (real_size > size)
849 ext_entry = (void *)(ext_acl + 1);
850 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
852 for (n=0; n < acl->a_count; n++, ext_entry++) {
853 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
854 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
855 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
856 switch(acl_e->e_tag) {
859 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
863 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
866 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
872 EXPORT_SYMBOL (posix_acl_to_xattr);
875 * vfs_posix_acl_to_xattr - convert from kernel to userspace representation
876 * @idmap: idmap of the mount
877 * @inode: inode the posix acls are set on
878 * @acl: the posix acls as represented by the vfs
879 * @buffer: the buffer into which to convert @acl
880 * @size: size of @buffer
882 * This converts @acl from the VFS representation in the filesystem idmapping
883 * to the uapi form reportable to userspace. And mount and caller idmappings
884 * are handled appropriately.
886 * Return: On success, the size of the stored uapi posix acls, on error a
889 static ssize_t vfs_posix_acl_to_xattr(struct mnt_idmap *idmap,
891 const struct posix_acl *acl, void *buffer,
895 struct posix_acl_xattr_header *ext_acl = buffer;
896 struct posix_acl_xattr_entry *ext_entry;
897 struct user_namespace *fs_userns, *caller_userns;
898 struct user_namespace *mnt_userns;
899 ssize_t real_size, n;
903 real_size = posix_acl_xattr_size(acl->a_count);
906 if (real_size > size)
909 ext_entry = (void *)(ext_acl + 1);
910 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
912 fs_userns = i_user_ns(inode);
913 caller_userns = current_user_ns();
914 mnt_userns = mnt_idmap_owner(idmap);
915 for (n=0; n < acl->a_count; n++, ext_entry++) {
916 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
917 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
918 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
919 switch(acl_e->e_tag) {
921 vfsuid = make_vfsuid(mnt_userns, fs_userns, acl_e->e_uid);
922 ext_entry->e_id = cpu_to_le32(from_kuid(
923 caller_userns, vfsuid_into_kuid(vfsuid)));
926 vfsgid = make_vfsgid(mnt_userns, fs_userns, acl_e->e_gid);
927 ext_entry->e_id = cpu_to_le32(from_kgid(
928 caller_userns, vfsgid_into_kgid(vfsgid)));
931 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
939 set_posix_acl(struct mnt_idmap *idmap, struct dentry *dentry,
940 int type, struct posix_acl *acl)
942 struct inode *inode = d_inode(dentry);
944 if (!IS_POSIXACL(inode))
946 if (!inode->i_op->set_acl)
949 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
950 return acl ? -EACCES : 0;
951 if (!inode_owner_or_capable(idmap, inode))
955 int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
959 return inode->i_op->set_acl(idmap, dentry, acl, type);
961 EXPORT_SYMBOL(set_posix_acl);
964 posix_acl_xattr_list(struct dentry *dentry)
966 return IS_POSIXACL(d_backing_inode(dentry));
969 const struct xattr_handler posix_acl_access_xattr_handler = {
970 .name = XATTR_NAME_POSIX_ACL_ACCESS,
971 .flags = ACL_TYPE_ACCESS,
972 .list = posix_acl_xattr_list,
974 EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
976 const struct xattr_handler posix_acl_default_xattr_handler = {
977 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
978 .flags = ACL_TYPE_DEFAULT,
979 .list = posix_acl_xattr_list,
981 EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
983 int simple_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
984 struct posix_acl *acl, int type)
987 struct inode *inode = d_inode(dentry);
989 if (type == ACL_TYPE_ACCESS) {
990 error = posix_acl_update_mode(idmap, inode,
991 &inode->i_mode, &acl);
996 inode->i_ctime = current_time(inode);
997 if (IS_I_VERSION(inode))
998 inode_inc_iversion(inode);
999 set_cached_acl(inode, type, acl);
1003 int simple_acl_create(struct inode *dir, struct inode *inode)
1005 struct posix_acl *default_acl, *acl;
1008 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
1012 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
1013 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
1016 posix_acl_release(default_acl);
1018 posix_acl_release(acl);
1022 static int vfs_set_acl_idmapped_mnt(struct mnt_idmap *idmap,
1023 struct user_namespace *fs_userns,
1024 struct posix_acl *acl)
1026 struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
1028 for (int n = 0; n < acl->a_count; n++) {
1029 struct posix_acl_entry *acl_e = &acl->a_entries[n];
1031 switch (acl_e->e_tag) {
1033 acl_e->e_uid = from_vfsuid(mnt_userns, fs_userns,
1034 VFSUIDT_INIT(acl_e->e_uid));
1037 acl_e->e_gid = from_vfsgid(mnt_userns, fs_userns,
1038 VFSGIDT_INIT(acl_e->e_gid));
1047 * vfs_set_acl - set posix acls
1048 * @idmap: idmap of the mount
1049 * @dentry: the dentry based on which to set the posix acls
1050 * @acl_name: the name of the posix acl
1051 * @kacl: the posix acls in the appropriate VFS format
1053 * This function sets @kacl. The caller must all posix_acl_release() on @kacl
1056 * Return: On success 0, on error negative errno.
1058 int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1059 const char *acl_name, struct posix_acl *kacl)
1063 struct inode *inode = d_inode(dentry);
1064 struct inode *delegated_inode = NULL;
1066 acl_type = posix_acl_type(acl_name);
1072 * If we're on an idmapped mount translate from mount specific
1073 * vfs{g,u}id_t into global filesystem k{g,u}id_t.
1074 * Afterwards we can cache the POSIX ACLs filesystem wide and -
1075 * if this is a filesystem with a backing store - ultimately
1076 * translate them to backing store values.
1078 error = vfs_set_acl_idmapped_mnt(idmap, i_user_ns(inode), kacl);
1087 * We only care about restrictions the inode struct itself places upon
1088 * us otherwise POSIX ACLs aren't subject to any VFS restrictions.
1090 error = may_write_xattr(idmap, inode);
1092 goto out_inode_unlock;
1094 error = security_inode_set_acl(idmap, dentry, acl_name, kacl);
1096 goto out_inode_unlock;
1098 error = try_break_deleg(inode, &delegated_inode);
1100 goto out_inode_unlock;
1102 if (inode->i_opflags & IOP_XATTR)
1103 error = set_posix_acl(idmap, dentry, acl_type, kacl);
1104 else if (unlikely(is_bad_inode(inode)))
1107 error = -EOPNOTSUPP;
1109 fsnotify_xattr(dentry);
1110 evm_inode_post_set_acl(dentry, acl_name, kacl);
1114 inode_unlock(inode);
1116 if (delegated_inode) {
1117 error = break_deleg_wait(&delegated_inode);
1124 EXPORT_SYMBOL_GPL(vfs_set_acl);
1127 * vfs_get_acl - get posix acls
1128 * @idmap: idmap of the mount
1129 * @dentry: the dentry based on which to retrieve the posix acls
1130 * @acl_name: the name of the posix acl
1132 * This function retrieves @kacl from the filesystem. The caller must all
1133 * posix_acl_release() on @kacl.
1135 * Return: On success POSIX ACLs in VFS format, on error negative errno.
1137 struct posix_acl *vfs_get_acl(struct mnt_idmap *idmap,
1138 struct dentry *dentry, const char *acl_name)
1140 struct inode *inode = d_inode(dentry);
1141 struct posix_acl *acl;
1142 int acl_type, error;
1144 acl_type = posix_acl_type(acl_name);
1146 return ERR_PTR(-EINVAL);
1149 * The VFS has no restrictions on reading POSIX ACLs so calling
1150 * something like xattr_permission() isn't needed. Only LSMs get a say.
1152 error = security_inode_get_acl(idmap, dentry, acl_name);
1154 return ERR_PTR(error);
1156 if (!IS_POSIXACL(inode))
1157 return ERR_PTR(-EOPNOTSUPP);
1158 if (S_ISLNK(inode->i_mode))
1159 return ERR_PTR(-EOPNOTSUPP);
1161 acl = __get_acl(idmap, dentry, inode, acl_type);
1165 return ERR_PTR(-ENODATA);
1169 EXPORT_SYMBOL_GPL(vfs_get_acl);
1172 * vfs_remove_acl - remove posix acls
1173 * @idmap: idmap of the mount
1174 * @dentry: the dentry based on which to retrieve the posix acls
1175 * @acl_name: the name of the posix acl
1177 * This function removes posix acls.
1179 * Return: On success 0, on error negative errno.
1181 int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1182 const char *acl_name)
1186 struct inode *inode = d_inode(dentry);
1187 struct inode *delegated_inode = NULL;
1189 acl_type = posix_acl_type(acl_name);
1197 * We only care about restrictions the inode struct itself places upon
1198 * us otherwise POSIX ACLs aren't subject to any VFS restrictions.
1200 error = may_write_xattr(idmap, inode);
1202 goto out_inode_unlock;
1204 error = security_inode_remove_acl(idmap, dentry, acl_name);
1206 goto out_inode_unlock;
1208 error = try_break_deleg(inode, &delegated_inode);
1210 goto out_inode_unlock;
1212 if (inode->i_opflags & IOP_XATTR)
1213 error = set_posix_acl(idmap, dentry, acl_type, NULL);
1214 else if (unlikely(is_bad_inode(inode)))
1217 error = -EOPNOTSUPP;
1219 fsnotify_xattr(dentry);
1220 evm_inode_post_remove_acl(idmap, dentry, acl_name);
1224 inode_unlock(inode);
1226 if (delegated_inode) {
1227 error = break_deleg_wait(&delegated_inode);
1234 EXPORT_SYMBOL_GPL(vfs_remove_acl);
1236 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1237 const char *acl_name, const void *kvalue, size_t size)
1240 struct posix_acl *acl = NULL;
1244 * Note that posix_acl_from_xattr() uses GFP_NOFS when it
1245 * probably doesn't need to here.
1247 acl = posix_acl_from_xattr(current_user_ns(), kvalue, size);
1249 return PTR_ERR(acl);
1252 error = vfs_set_acl(idmap, dentry, acl_name, acl);
1253 posix_acl_release(acl);
1257 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1258 const char *acl_name, void *kvalue, size_t size)
1261 struct posix_acl *acl;
1263 acl = vfs_get_acl(idmap, dentry, acl_name);
1265 return PTR_ERR(acl);
1267 error = vfs_posix_acl_to_xattr(idmap, d_inode(dentry),
1269 posix_acl_release(acl);