4 * Almost all from linux/fs/ext2/acl.c:
5 * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
8 #include <linux/export.h>
10 #include <linux/posix_acl_xattr.h>
11 #include <linux/gfp.h>
12 #include <linux/user_namespace.h>
15 * Fix up the uids and gids in posix acl extended attributes in place.
17 static void posix_acl_fix_xattr_userns(
18 struct user_namespace *to, struct user_namespace *from,
19 void *value, size_t size)
21 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
22 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
29 if (size < sizeof(posix_acl_xattr_header))
31 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
34 count = posix_acl_xattr_count(size);
40 for (end = entry + count; entry != end; entry++) {
41 switch(le16_to_cpu(entry->e_tag)) {
43 uid = make_kuid(from, le32_to_cpu(entry->e_id));
44 entry->e_id = cpu_to_le32(from_kuid(to, uid));
47 gid = make_kgid(from, le32_to_cpu(entry->e_id));
48 entry->e_id = cpu_to_le32(from_kuid(to, uid));
56 void posix_acl_fix_xattr_from_user(void *value, size_t size)
58 struct user_namespace *user_ns = current_user_ns();
59 if (user_ns == &init_user_ns)
61 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
64 void posix_acl_fix_xattr_to_user(void *value, size_t size)
66 struct user_namespace *user_ns = current_user_ns();
67 if (user_ns == &init_user_ns)
69 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
73 * Convert from extended attribute to in-memory representation.
76 posix_acl_from_xattr(const void *value, size_t size)
78 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
79 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
81 struct posix_acl *acl;
82 struct posix_acl_entry *acl_e;
86 if (size < sizeof(posix_acl_xattr_header))
87 return ERR_PTR(-EINVAL);
88 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
89 return ERR_PTR(-EOPNOTSUPP);
91 count = posix_acl_xattr_count(size);
93 return ERR_PTR(-EINVAL);
97 acl = posix_acl_alloc(count, GFP_NOFS);
99 return ERR_PTR(-ENOMEM);
100 acl_e = acl->a_entries;
102 for (end = entry + count; entry != end; acl_e++, entry++) {
103 acl_e->e_tag = le16_to_cpu(entry->e_tag);
104 acl_e->e_perm = le16_to_cpu(entry->e_perm);
106 switch(acl_e->e_tag) {
115 make_kuid(&init_user_ns,
116 le32_to_cpu(entry->e_id));
117 if (!uid_valid(acl_e->e_uid))
122 make_kgid(&init_user_ns,
123 le32_to_cpu(entry->e_id));
124 if (!gid_valid(acl_e->e_gid))
135 posix_acl_release(acl);
136 return ERR_PTR(-EINVAL);
138 EXPORT_SYMBOL (posix_acl_from_xattr);
141 * Convert from in-memory to extended attribute representation.
144 posix_acl_to_xattr(const struct posix_acl *acl, void *buffer, size_t size)
146 posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
147 posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
150 real_size = posix_acl_xattr_size(acl->a_count);
153 if (real_size > size)
156 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
158 for (n=0; n < acl->a_count; n++, ext_entry++) {
159 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
160 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
161 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
162 switch(acl_e->e_tag) {
165 cpu_to_le32(from_kuid(&init_user_ns, acl_e->e_uid));
169 cpu_to_le32(from_kgid(&init_user_ns, acl_e->e_gid));
172 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
178 EXPORT_SYMBOL (posix_acl_to_xattr);