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-rw-r--r--fs/nfs_common/nfsacl.c257
1 files changed, 257 insertions, 0 deletions
diff --git a/fs/nfs_common/nfsacl.c b/fs/nfs_common/nfsacl.c
new file mode 100644
index 000000000000..18c58c32e326
--- /dev/null
+++ b/fs/nfs_common/nfsacl.c
@@ -0,0 +1,257 @@
1/*
2 * fs/nfs_common/nfsacl.c
3 *
4 * Copyright (C) 2002-2003 Andreas Gruenbacher <agruen@suse.de>
5 */
6
7/*
8 * The Solaris nfsacl protocol represents some ACLs slightly differently
9 * than POSIX 1003.1e draft 17 does (and we do):
10 *
11 * - Minimal ACLs always have an ACL_MASK entry, so they have
12 * four instead of three entries.
13 * - The ACL_MASK entry in such minimal ACLs always has the same
14 * permissions as the ACL_GROUP_OBJ entry. (In extended ACLs
15 * the ACL_MASK and ACL_GROUP_OBJ entries may differ.)
16 * - The identifier fields of the ACL_USER_OBJ and ACL_GROUP_OBJ
17 * entries contain the identifiers of the owner and owning group.
18 * (In POSIX ACLs we always set them to ACL_UNDEFINED_ID).
19 * - ACL entries in the kernel are kept sorted in ascending order
20 * of (e_tag, e_id). Solaris ACLs are unsorted.
21 */
22
23#include <linux/module.h>
24#include <linux/fs.h>
25#include <linux/sunrpc/xdr.h>
26#include <linux/nfsacl.h>
27#include <linux/nfs3.h>
28#include <linux/sort.h>
29
30MODULE_LICENSE("GPL");
31
32EXPORT_SYMBOL(nfsacl_encode);
33EXPORT_SYMBOL(nfsacl_decode);
34
35struct nfsacl_encode_desc {
36 struct xdr_array2_desc desc;
37 unsigned int count;
38 struct posix_acl *acl;
39 int typeflag;
40 uid_t uid;
41 gid_t gid;
42};
43
44static int
45xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem)
46{
47 struct nfsacl_encode_desc *nfsacl_desc =
48 (struct nfsacl_encode_desc *) desc;
49 u32 *p = (u32 *) elem;
50
51 if (nfsacl_desc->count < nfsacl_desc->acl->a_count) {
52 struct posix_acl_entry *entry =
53 &nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
54
55 *p++ = htonl(entry->e_tag | nfsacl_desc->typeflag);
56 switch(entry->e_tag) {
57 case ACL_USER_OBJ:
58 *p++ = htonl(nfsacl_desc->uid);
59 break;
60 case ACL_GROUP_OBJ:
61 *p++ = htonl(nfsacl_desc->gid);
62 break;
63 case ACL_USER:
64 case ACL_GROUP:
65 *p++ = htonl(entry->e_id);
66 break;
67 default: /* Solaris depends on that! */
68 *p++ = 0;
69 break;
70 }
71 *p++ = htonl(entry->e_perm & S_IRWXO);
72 } else {
73 const struct posix_acl_entry *pa, *pe;
74 int group_obj_perm = ACL_READ|ACL_WRITE|ACL_EXECUTE;
75
76 FOREACH_ACL_ENTRY(pa, nfsacl_desc->acl, pe) {
77 if (pa->e_tag == ACL_GROUP_OBJ) {
78 group_obj_perm = pa->e_perm & S_IRWXO;
79 break;
80 }
81 }
82 /* fake up ACL_MASK entry */
83 *p++ = htonl(ACL_MASK | nfsacl_desc->typeflag);
84 *p++ = htonl(0);
85 *p++ = htonl(group_obj_perm);
86 }
87
88 return 0;
89}
90
91unsigned int
92nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
93 struct posix_acl *acl, int encode_entries, int typeflag)
94{
95 int entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0;
96 struct nfsacl_encode_desc nfsacl_desc = {
97 .desc = {
98 .elem_size = 12,
99 .array_len = encode_entries ? entries : 0,
100 .xcode = xdr_nfsace_encode,
101 },
102 .acl = acl,
103 .typeflag = typeflag,
104 .uid = inode->i_uid,
105 .gid = inode->i_gid,
106 };
107 int err;
108
109 if (entries > NFS_ACL_MAX_ENTRIES ||
110 xdr_encode_word(buf, base, entries))
111 return -EINVAL;
112 err = xdr_encode_array2(buf, base + 4, &nfsacl_desc.desc);
113 if (!err)
114 err = 8 + nfsacl_desc.desc.elem_size *
115 nfsacl_desc.desc.array_len;
116 return err;
117}
118
119struct nfsacl_decode_desc {
120 struct xdr_array2_desc desc;
121 unsigned int count;
122 struct posix_acl *acl;
123};
124
125static int
126xdr_nfsace_decode(struct xdr_array2_desc *desc, void *elem)
127{
128 struct nfsacl_decode_desc *nfsacl_desc =
129 (struct nfsacl_decode_desc *) desc;
130 u32 *p = (u32 *) elem;
131 struct posix_acl_entry *entry;
132
133 if (!nfsacl_desc->acl) {
134 if (desc->array_len > NFS_ACL_MAX_ENTRIES)
135 return -EINVAL;
136 nfsacl_desc->acl = posix_acl_alloc(desc->array_len, GFP_KERNEL);
137 if (!nfsacl_desc->acl)
138 return -ENOMEM;
139 nfsacl_desc->count = 0;
140 }
141
142 entry = &nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
143 entry->e_tag = ntohl(*p++) & ~NFS_ACL_DEFAULT;
144 entry->e_id = ntohl(*p++);
145 entry->e_perm = ntohl(*p++);
146
147 switch(entry->e_tag) {
148 case ACL_USER_OBJ:
149 case ACL_USER:
150 case ACL_GROUP_OBJ:
151 case ACL_GROUP:
152 case ACL_OTHER:
153 if (entry->e_perm & ~S_IRWXO)
154 return -EINVAL;
155 break;
156 case ACL_MASK:
157 /* Solaris sometimes sets additonal bits in the mask */
158 entry->e_perm &= S_IRWXO;
159 break;
160 default:
161 return -EINVAL;
162 }
163
164 return 0;
165}
166
167static int
168cmp_acl_entry(const void *x, const void *y)
169{
170 const struct posix_acl_entry *a = x, *b = y;
171
172 if (a->e_tag != b->e_tag)
173 return a->e_tag - b->e_tag;
174 else if (a->e_id > b->e_id)
175 return 1;
176 else if (a->e_id < b->e_id)
177 return -1;
178 else
179 return 0;
180}
181
182/*
183 * Convert from a Solaris ACL to a POSIX 1003.1e draft 17 ACL.
184 */
185static int
186posix_acl_from_nfsacl(struct posix_acl *acl)
187{
188 struct posix_acl_entry *pa, *pe,
189 *group_obj = NULL, *mask = NULL;
190
191 if (!acl)
192 return 0;
193
194 sort(acl->a_entries, acl->a_count, sizeof(struct posix_acl_entry),
195 cmp_acl_entry, NULL);
196
197 /* Clear undefined identifier fields and find the ACL_GROUP_OBJ
198 and ACL_MASK entries. */
199 FOREACH_ACL_ENTRY(pa, acl, pe) {
200 switch(pa->e_tag) {
201 case ACL_USER_OBJ:
202 pa->e_id = ACL_UNDEFINED_ID;
203 break;
204 case ACL_GROUP_OBJ:
205 pa->e_id = ACL_UNDEFINED_ID;
206 group_obj = pa;
207 break;
208 case ACL_MASK:
209 mask = pa;
210 /* fall through */
211 case ACL_OTHER:
212 pa->e_id = ACL_UNDEFINED_ID;
213 break;
214 }
215 }
216 if (acl->a_count == 4 && group_obj && mask &&
217 mask->e_perm == group_obj->e_perm) {
218 /* remove bogus ACL_MASK entry */
219 memmove(mask, mask+1, (3 - (mask - acl->a_entries)) *
220 sizeof(struct posix_acl_entry));
221 acl->a_count = 3;
222 }
223 return 0;
224}
225
226unsigned int
227nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
228 struct posix_acl **pacl)
229{
230 struct nfsacl_decode_desc nfsacl_desc = {
231 .desc = {
232 .elem_size = 12,
233 .xcode = pacl ? xdr_nfsace_decode : NULL,
234 },
235 };
236 u32 entries;
237 int err;
238
239 if (xdr_decode_word(buf, base, &entries) ||
240 entries > NFS_ACL_MAX_ENTRIES)
241 return -EINVAL;
242 err = xdr_decode_array2(buf, base + 4, &nfsacl_desc.desc);
243 if (err)
244 return err;
245 if (pacl) {
246 if (entries != nfsacl_desc.desc.array_len ||
247 posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) {
248 posix_acl_release(nfsacl_desc.acl);
249 return -EINVAL;
250 }
251 *pacl = nfsacl_desc.acl;
252 }
253 if (aclcnt)
254 *aclcnt = entries;
255 return 8 + nfsacl_desc.desc.elem_size *
256 nfsacl_desc.desc.array_len;
257}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-12 11:28:13 -0500