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>
31 #include <linux/filelock.h>
35 static struct posix_acl **acl_by_type(struct inode *inode, int type)
40 case ACL_TYPE_DEFAULT:
41 return &inode->i_default_acl;
47 struct posix_acl *get_cached_acl(struct inode *inode, int type)
49 struct posix_acl **p = acl_by_type(inode, type);
50 struct posix_acl *acl;
54 acl = rcu_dereference(*p);
55 if (!acl || is_uncached_acl(acl) ||
56 refcount_inc_not_zero(&acl->a_refcount))
64 EXPORT_SYMBOL(get_cached_acl);
66 struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
68 struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type));
70 if (acl == ACL_DONT_CACHE) {
71 struct posix_acl *ret;
73 ret = inode->i_op->get_inode_acl(inode, type, LOOKUP_RCU);
80 EXPORT_SYMBOL(get_cached_acl_rcu);
82 void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
84 struct posix_acl **p = acl_by_type(inode, type);
85 struct posix_acl *old;
87 old = xchg(p, posix_acl_dup(acl));
88 if (!is_uncached_acl(old))
89 posix_acl_release(old);
91 EXPORT_SYMBOL(set_cached_acl);
93 static void __forget_cached_acl(struct posix_acl **p)
95 struct posix_acl *old;
97 old = xchg(p, ACL_NOT_CACHED);
98 if (!is_uncached_acl(old))
99 posix_acl_release(old);
102 void forget_cached_acl(struct inode *inode, int type)
104 __forget_cached_acl(acl_by_type(inode, type));
106 EXPORT_SYMBOL(forget_cached_acl);
108 void forget_all_cached_acls(struct inode *inode)
110 __forget_cached_acl(&inode->i_acl);
111 __forget_cached_acl(&inode->i_default_acl);
113 EXPORT_SYMBOL(forget_all_cached_acls);
115 static struct posix_acl *__get_acl(struct mnt_idmap *idmap,
116 struct dentry *dentry, struct inode *inode,
119 struct posix_acl *sentinel;
120 struct posix_acl **p;
121 struct posix_acl *acl;
124 * The sentinel is used to detect when another operation like
125 * set_cached_acl() or forget_cached_acl() races with get_inode_acl().
126 * It is guaranteed that is_uncached_acl(sentinel) is true.
129 acl = get_cached_acl(inode, type);
130 if (!is_uncached_acl(acl))
133 if (!IS_POSIXACL(inode))
136 sentinel = uncached_acl_sentinel(current);
137 p = acl_by_type(inode, type);
140 * If the ACL isn't being read yet, set our sentinel. Otherwise, the
141 * current value of the ACL will not be ACL_NOT_CACHED and so our own
142 * sentinel will not be set; another task will update the cache. We
143 * could wait for that other task to complete its job, but it's easier
144 * to just call ->get_inode_acl to fetch the ACL ourself. (This is
145 * going to be an unlikely race.)
147 cmpxchg(p, ACL_NOT_CACHED, sentinel);
150 * Normally, the ACL returned by ->get{_inode}_acl will be cached.
151 * A filesystem can prevent that by calling
152 * forget_cached_acl(inode, type) in ->get{_inode}_acl.
154 * If the filesystem doesn't have a get{_inode}_ acl() function at all,
155 * we'll just create the negative cache entry.
157 if (dentry && inode->i_op->get_acl) {
158 acl = inode->i_op->get_acl(idmap, dentry, type);
159 } else if (inode->i_op->get_inode_acl) {
160 acl = inode->i_op->get_inode_acl(inode, type, false);
162 set_cached_acl(inode, type, NULL);
167 * Remove our sentinel so that we don't block future attempts
170 cmpxchg(p, sentinel, ACL_NOT_CACHED);
175 * Cache the result, but only if our sentinel is still in place.
178 if (unlikely(!try_cmpxchg(p, &sentinel, acl)))
179 posix_acl_release(acl);
183 struct posix_acl *get_inode_acl(struct inode *inode, int type)
185 return __get_acl(&nop_mnt_idmap, NULL, inode, type);
187 EXPORT_SYMBOL(get_inode_acl);
190 * Init a fresh posix_acl
193 posix_acl_init(struct posix_acl *acl, int count)
195 refcount_set(&acl->a_refcount, 1);
196 acl->a_count = count;
198 EXPORT_SYMBOL(posix_acl_init);
201 * Allocate a new ACL with the specified number of entries.
204 posix_acl_alloc(int count, gfp_t flags)
206 const size_t size = sizeof(struct posix_acl) +
207 count * sizeof(struct posix_acl_entry);
208 struct posix_acl *acl = kmalloc(size, flags);
210 posix_acl_init(acl, count);
213 EXPORT_SYMBOL(posix_acl_alloc);
219 posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
221 struct posix_acl *clone = NULL;
224 int size = sizeof(struct posix_acl) + acl->a_count *
225 sizeof(struct posix_acl_entry);
226 clone = kmemdup(acl, size, flags);
228 refcount_set(&clone->a_refcount, 1);
232 EXPORT_SYMBOL_GPL(posix_acl_clone);
235 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
238 posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
240 const struct posix_acl_entry *pa, *pe;
241 int state = ACL_USER_OBJ;
244 FOREACH_ACL_ENTRY(pa, acl, pe) {
245 if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
249 if (state == ACL_USER_OBJ) {
256 if (state != ACL_USER)
258 if (!kuid_has_mapping(user_ns, pa->e_uid))
264 if (state == ACL_USER) {
271 if (state != ACL_GROUP)
273 if (!kgid_has_mapping(user_ns, pa->e_gid))
279 if (state != ACL_GROUP)
285 if (state == ACL_OTHER ||
286 (state == ACL_GROUP && !needs_mask)) {
300 EXPORT_SYMBOL(posix_acl_valid);
303 * Returns 0 if the acl can be exactly represented in the traditional
304 * file mode permission bits, or else 1. Returns -E... on error.
307 posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
309 const struct posix_acl_entry *pa, *pe;
314 * A null ACL can always be presented as mode bits.
319 FOREACH_ACL_ENTRY(pa, acl, pe) {
322 mode |= (pa->e_perm & S_IRWXO) << 6;
325 mode |= (pa->e_perm & S_IRWXO) << 3;
328 mode |= pa->e_perm & S_IRWXO;
331 mode = (mode & ~S_IRWXG) |
332 ((pa->e_perm & S_IRWXO) << 3);
344 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
347 EXPORT_SYMBOL(posix_acl_equiv_mode);
350 * Create an ACL representing the file mode permission bits of an inode.
353 posix_acl_from_mode(umode_t mode, gfp_t flags)
355 struct posix_acl *acl = posix_acl_alloc(3, flags);
357 return ERR_PTR(-ENOMEM);
359 acl->a_entries[0].e_tag = ACL_USER_OBJ;
360 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
362 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
363 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
365 acl->a_entries[2].e_tag = ACL_OTHER;
366 acl->a_entries[2].e_perm = (mode & S_IRWXO);
369 EXPORT_SYMBOL(posix_acl_from_mode);
372 * Return 0 if current is granted want access to the inode
373 * by the acl. Returns -E... otherwise.
376 posix_acl_permission(struct mnt_idmap *idmap, struct inode *inode,
377 const struct posix_acl *acl, int want)
379 const struct posix_acl_entry *pa, *pe, *mask_obj;
380 struct user_namespace *fs_userns = i_user_ns(inode);
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(idmap, inode);
392 if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
396 vfsuid = make_vfsuid(idmap, fs_userns,
398 if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
402 vfsgid = i_gid_into_vfsgid(idmap, inode);
403 if (vfsgid_in_group_p(vfsgid)) {
405 if ((pa->e_perm & want) == want)
410 vfsgid = make_vfsgid(idmap, 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 umode_t mode = inode->i_mode;
714 error = posix_acl_equiv_mode(*acl, &mode);
719 if (!vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode)) &&
720 !capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID))
725 EXPORT_SYMBOL(posix_acl_update_mode);
728 * Fix up the uids and gids in posix acl extended attributes in place.
730 static int posix_acl_fix_xattr_common(const void *value, size_t size)
732 const struct posix_acl_xattr_header *header = value;
737 if (size < sizeof(struct posix_acl_xattr_header))
739 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
742 count = posix_acl_xattr_count(size);
752 * posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format
753 * @userns: the filesystem's idmapping
754 * @value: the uapi representation of POSIX ACLs
755 * @size: the size of @void
757 * Filesystems that store POSIX ACLs in the unaltered uapi format should use
758 * posix_acl_from_xattr() when reading them from the backing store and
759 * converting them into the struct posix_acl VFS format. The helper is
760 * specifically intended to be called from the acl inode operation.
762 * The posix_acl_from_xattr() function will map the raw {g,u}id values stored
763 * in ACL_{GROUP,USER} entries into idmapping in @userns.
765 * Note that posix_acl_from_xattr() does not take idmapped mounts into account.
766 * If it did it calling it from the get acl inode operation would return POSIX
767 * ACLs mapped according to an idmapped mount which would mean that the value
768 * couldn't be cached for the filesystem. Idmapped mounts are taken into
769 * account on the fly during permission checking or right at the VFS -
770 * userspace boundary before reporting them to the user.
772 * Return: Allocated struct posix_acl on success, NULL for a valid header but
773 * without actual POSIX ACL entries, or ERR_PTR() encoded error code.
775 struct posix_acl *posix_acl_from_xattr(struct user_namespace *userns,
776 const void *value, size_t size)
778 const struct posix_acl_xattr_header *header = value;
779 const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
781 struct posix_acl *acl;
782 struct posix_acl_entry *acl_e;
784 count = posix_acl_fix_xattr_common(value, size);
786 return ERR_PTR(count);
790 acl = posix_acl_alloc(count, GFP_NOFS);
792 return ERR_PTR(-ENOMEM);
793 acl_e = acl->a_entries;
795 for (end = entry + count; entry != end; acl_e++, entry++) {
796 acl_e->e_tag = le16_to_cpu(entry->e_tag);
797 acl_e->e_perm = le16_to_cpu(entry->e_perm);
799 switch(acl_e->e_tag) {
807 acl_e->e_uid = make_kuid(userns,
808 le32_to_cpu(entry->e_id));
809 if (!uid_valid(acl_e->e_uid))
813 acl_e->e_gid = make_kgid(userns,
814 le32_to_cpu(entry->e_id));
815 if (!gid_valid(acl_e->e_gid))
826 posix_acl_release(acl);
827 return ERR_PTR(-EINVAL);
829 EXPORT_SYMBOL (posix_acl_from_xattr);
832 * Convert from in-memory to extended attribute representation.
835 posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
836 void *buffer, size_t size)
838 struct posix_acl_xattr_header *ext_acl = buffer;
839 struct posix_acl_xattr_entry *ext_entry;
842 real_size = posix_acl_xattr_size(acl->a_count);
845 if (real_size > size)
848 ext_entry = (void *)(ext_acl + 1);
849 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
851 for (n=0; n < acl->a_count; n++, ext_entry++) {
852 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
853 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
854 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
855 switch(acl_e->e_tag) {
858 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
862 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
865 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
871 EXPORT_SYMBOL (posix_acl_to_xattr);
874 * vfs_posix_acl_to_xattr - convert from kernel to userspace representation
875 * @idmap: idmap of the mount
876 * @inode: inode the posix acls are set on
877 * @acl: the posix acls as represented by the vfs
878 * @buffer: the buffer into which to convert @acl
879 * @size: size of @buffer
881 * This converts @acl from the VFS representation in the filesystem idmapping
882 * to the uapi form reportable to userspace. And mount and caller idmappings
883 * are handled appropriately.
885 * Return: On success, the size of the stored uapi posix acls, on error a
888 static ssize_t vfs_posix_acl_to_xattr(struct mnt_idmap *idmap,
890 const struct posix_acl *acl, void *buffer,
894 struct posix_acl_xattr_header *ext_acl = buffer;
895 struct posix_acl_xattr_entry *ext_entry;
896 struct user_namespace *fs_userns, *caller_userns;
897 ssize_t real_size, n;
901 real_size = posix_acl_xattr_size(acl->a_count);
904 if (real_size > size)
907 ext_entry = (void *)(ext_acl + 1);
908 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
910 fs_userns = i_user_ns(inode);
911 caller_userns = current_user_ns();
912 for (n=0; n < acl->a_count; n++, ext_entry++) {
913 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
914 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
915 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
916 switch(acl_e->e_tag) {
918 vfsuid = make_vfsuid(idmap, fs_userns, acl_e->e_uid);
919 ext_entry->e_id = cpu_to_le32(from_kuid(
920 caller_userns, vfsuid_into_kuid(vfsuid)));
923 vfsgid = make_vfsgid(idmap, fs_userns, acl_e->e_gid);
924 ext_entry->e_id = cpu_to_le32(from_kgid(
925 caller_userns, vfsgid_into_kgid(vfsgid)));
928 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
936 set_posix_acl(struct mnt_idmap *idmap, struct dentry *dentry,
937 int type, struct posix_acl *acl)
939 struct inode *inode = d_inode(dentry);
941 if (!IS_POSIXACL(inode))
943 if (!inode->i_op->set_acl)
946 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
947 return acl ? -EACCES : 0;
948 if (!inode_owner_or_capable(idmap, inode))
952 int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
956 return inode->i_op->set_acl(idmap, dentry, acl, type);
958 EXPORT_SYMBOL(set_posix_acl);
960 int posix_acl_listxattr(struct inode *inode, char **buffer,
961 ssize_t *remaining_size)
965 if (!IS_POSIXACL(inode))
969 err = xattr_list_one(buffer, remaining_size,
970 XATTR_NAME_POSIX_ACL_ACCESS);
975 if (inode->i_default_acl) {
976 err = xattr_list_one(buffer, remaining_size,
977 XATTR_NAME_POSIX_ACL_DEFAULT);
986 posix_acl_xattr_list(struct dentry *dentry)
988 return IS_POSIXACL(d_backing_inode(dentry));
992 * nop_posix_acl_access - legacy xattr handler for access POSIX ACLs
994 * This is the legacy POSIX ACL access xattr handler. It is used by some
995 * filesystems to implement their ->listxattr() inode operation. New code
996 * should never use them.
998 const struct xattr_handler nop_posix_acl_access = {
999 .name = XATTR_NAME_POSIX_ACL_ACCESS,
1000 .list = posix_acl_xattr_list,
1002 EXPORT_SYMBOL_GPL(nop_posix_acl_access);
1005 * nop_posix_acl_default - legacy xattr handler for default POSIX ACLs
1007 * This is the legacy POSIX ACL default xattr handler. It is used by some
1008 * filesystems to implement their ->listxattr() inode operation. New code
1009 * should never use them.
1011 const struct xattr_handler nop_posix_acl_default = {
1012 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
1013 .list = posix_acl_xattr_list,
1015 EXPORT_SYMBOL_GPL(nop_posix_acl_default);
1017 int simple_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1018 struct posix_acl *acl, int type)
1021 struct inode *inode = d_inode(dentry);
1023 if (type == ACL_TYPE_ACCESS) {
1024 error = posix_acl_update_mode(idmap, inode,
1025 &inode->i_mode, &acl);
1030 inode_set_ctime_current(inode);
1031 if (IS_I_VERSION(inode))
1032 inode_inc_iversion(inode);
1033 set_cached_acl(inode, type, acl);
1037 int simple_acl_create(struct inode *dir, struct inode *inode)
1039 struct posix_acl *default_acl, *acl;
1042 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
1046 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
1047 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
1050 posix_acl_release(default_acl);
1052 posix_acl_release(acl);
1056 static int vfs_set_acl_idmapped_mnt(struct mnt_idmap *idmap,
1057 struct user_namespace *fs_userns,
1058 struct posix_acl *acl)
1060 for (int n = 0; n < acl->a_count; n++) {
1061 struct posix_acl_entry *acl_e = &acl->a_entries[n];
1063 switch (acl_e->e_tag) {
1065 acl_e->e_uid = from_vfsuid(idmap, fs_userns,
1066 VFSUIDT_INIT(acl_e->e_uid));
1069 acl_e->e_gid = from_vfsgid(idmap, fs_userns,
1070 VFSGIDT_INIT(acl_e->e_gid));
1079 * vfs_set_acl - set posix acls
1080 * @idmap: idmap of the mount
1081 * @dentry: the dentry based on which to set the posix acls
1082 * @acl_name: the name of the posix acl
1083 * @kacl: the posix acls in the appropriate VFS format
1085 * This function sets @kacl. The caller must all posix_acl_release() on @kacl
1088 * Return: On success 0, on error negative errno.
1090 int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1091 const char *acl_name, struct posix_acl *kacl)
1095 struct inode *inode = d_inode(dentry);
1096 struct inode *delegated_inode = NULL;
1098 acl_type = posix_acl_type(acl_name);
1104 * If we're on an idmapped mount translate from mount specific
1105 * vfs{g,u}id_t into global filesystem k{g,u}id_t.
1106 * Afterwards we can cache the POSIX ACLs filesystem wide and -
1107 * if this is a filesystem with a backing store - ultimately
1108 * translate them to backing store values.
1110 error = vfs_set_acl_idmapped_mnt(idmap, i_user_ns(inode), kacl);
1119 * We only care about restrictions the inode struct itself places upon
1120 * us otherwise POSIX ACLs aren't subject to any VFS restrictions.
1122 error = may_write_xattr(idmap, inode);
1124 goto out_inode_unlock;
1126 error = security_inode_set_acl(idmap, dentry, acl_name, kacl);
1128 goto out_inode_unlock;
1130 error = try_break_deleg(inode, &delegated_inode);
1132 goto out_inode_unlock;
1134 if (likely(!is_bad_inode(inode)))
1135 error = set_posix_acl(idmap, dentry, acl_type, kacl);
1139 fsnotify_xattr(dentry);
1140 evm_inode_post_set_acl(dentry, acl_name, kacl);
1144 inode_unlock(inode);
1146 if (delegated_inode) {
1147 error = break_deleg_wait(&delegated_inode);
1154 EXPORT_SYMBOL_GPL(vfs_set_acl);
1157 * vfs_get_acl - get posix acls
1158 * @idmap: idmap of the mount
1159 * @dentry: the dentry based on which to retrieve the posix acls
1160 * @acl_name: the name of the posix acl
1162 * This function retrieves @kacl from the filesystem. The caller must all
1163 * posix_acl_release() on @kacl.
1165 * Return: On success POSIX ACLs in VFS format, on error negative errno.
1167 struct posix_acl *vfs_get_acl(struct mnt_idmap *idmap,
1168 struct dentry *dentry, const char *acl_name)
1170 struct inode *inode = d_inode(dentry);
1171 struct posix_acl *acl;
1172 int acl_type, error;
1174 acl_type = posix_acl_type(acl_name);
1176 return ERR_PTR(-EINVAL);
1179 * The VFS has no restrictions on reading POSIX ACLs so calling
1180 * something like xattr_permission() isn't needed. Only LSMs get a say.
1182 error = security_inode_get_acl(idmap, dentry, acl_name);
1184 return ERR_PTR(error);
1186 if (!IS_POSIXACL(inode))
1187 return ERR_PTR(-EOPNOTSUPP);
1188 if (S_ISLNK(inode->i_mode))
1189 return ERR_PTR(-EOPNOTSUPP);
1191 acl = __get_acl(idmap, dentry, inode, acl_type);
1195 return ERR_PTR(-ENODATA);
1199 EXPORT_SYMBOL_GPL(vfs_get_acl);
1202 * vfs_remove_acl - remove posix acls
1203 * @idmap: idmap of the mount
1204 * @dentry: the dentry based on which to retrieve the posix acls
1205 * @acl_name: the name of the posix acl
1207 * This function removes posix acls.
1209 * Return: On success 0, on error negative errno.
1211 int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1212 const char *acl_name)
1216 struct inode *inode = d_inode(dentry);
1217 struct inode *delegated_inode = NULL;
1219 acl_type = posix_acl_type(acl_name);
1227 * We only care about restrictions the inode struct itself places upon
1228 * us otherwise POSIX ACLs aren't subject to any VFS restrictions.
1230 error = may_write_xattr(idmap, inode);
1232 goto out_inode_unlock;
1234 error = security_inode_remove_acl(idmap, dentry, acl_name);
1236 goto out_inode_unlock;
1238 error = try_break_deleg(inode, &delegated_inode);
1240 goto out_inode_unlock;
1242 if (likely(!is_bad_inode(inode)))
1243 error = set_posix_acl(idmap, dentry, acl_type, NULL);
1247 fsnotify_xattr(dentry);
1248 evm_inode_post_remove_acl(idmap, dentry, acl_name);
1252 inode_unlock(inode);
1254 if (delegated_inode) {
1255 error = break_deleg_wait(&delegated_inode);
1262 EXPORT_SYMBOL_GPL(vfs_remove_acl);
1264 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1265 const char *acl_name, const void *kvalue, size_t size)
1268 struct posix_acl *acl = NULL;
1272 * Note that posix_acl_from_xattr() uses GFP_NOFS when it
1273 * probably doesn't need to here.
1275 acl = posix_acl_from_xattr(current_user_ns(), kvalue, size);
1277 return PTR_ERR(acl);
1280 error = vfs_set_acl(idmap, dentry, acl_name, acl);
1281 posix_acl_release(acl);
1285 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1286 const char *acl_name, void *kvalue, size_t size)
1289 struct posix_acl *acl;
1291 acl = vfs_get_acl(idmap, dentry, acl_name);
1293 return PTR_ERR(acl);
1295 error = vfs_posix_acl_to_xattr(idmap, d_inode(dentry),
1297 posix_acl_release(acl);