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a257cdd0 AG |
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> | |
5a0e3ad6 | 25 | #include <linux/gfp.h> |
a257cdd0 AG |
26 | #include <linux/sunrpc/xdr.h> |
27 | #include <linux/nfsacl.h> | |
28 | #include <linux/nfs3.h> | |
29 | #include <linux/sort.h> | |
30 | ||
31 | MODULE_LICENSE("GPL"); | |
32 | ||
a257cdd0 AG |
33 | struct nfsacl_encode_desc { |
34 | struct xdr_array2_desc desc; | |
35 | unsigned int count; | |
36 | struct posix_acl *acl; | |
37 | int typeflag; | |
ddca4e17 EB |
38 | kuid_t uid; |
39 | kgid_t gid; | |
a257cdd0 AG |
40 | }; |
41 | ||
f61f6da0 CL |
42 | struct nfsacl_simple_acl { |
43 | struct posix_acl acl; | |
44 | struct posix_acl_entry ace[4]; | |
45 | }; | |
46 | ||
a257cdd0 AG |
47 | static int |
48 | xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem) | |
49 | { | |
50 | struct nfsacl_encode_desc *nfsacl_desc = | |
51 | (struct nfsacl_encode_desc *) desc; | |
83bbe2ef | 52 | __be32 *p = elem; |
a257cdd0 | 53 | |
22c1ea44 AG |
54 | struct posix_acl_entry *entry = |
55 | &nfsacl_desc->acl->a_entries[nfsacl_desc->count++]; | |
a257cdd0 | 56 | |
22c1ea44 AG |
57 | *p++ = htonl(entry->e_tag | nfsacl_desc->typeflag); |
58 | switch(entry->e_tag) { | |
59 | case ACL_USER_OBJ: | |
ddca4e17 | 60 | *p++ = htonl(from_kuid(&init_user_ns, nfsacl_desc->uid)); |
22c1ea44 AG |
61 | break; |
62 | case ACL_GROUP_OBJ: | |
ddca4e17 | 63 | *p++ = htonl(from_kgid(&init_user_ns, nfsacl_desc->gid)); |
22c1ea44 AG |
64 | break; |
65 | case ACL_USER: | |
ddca4e17 EB |
66 | *p++ = htonl(from_kuid(&init_user_ns, entry->e_uid)); |
67 | break; | |
22c1ea44 | 68 | case ACL_GROUP: |
ddca4e17 | 69 | *p++ = htonl(from_kgid(&init_user_ns, entry->e_gid)); |
22c1ea44 AG |
70 | break; |
71 | default: /* Solaris depends on that! */ | |
72 | *p++ = 0; | |
73 | break; | |
a257cdd0 | 74 | } |
22c1ea44 | 75 | *p++ = htonl(entry->e_perm & S_IRWXO); |
a257cdd0 AG |
76 | return 0; |
77 | } | |
78 | ||
731f3f48 CL |
79 | /** |
80 | * nfsacl_encode - Encode an NFSv3 ACL | |
81 | * | |
82 | * @buf: destination xdr_buf to contain XDR encoded ACL | |
83 | * @base: byte offset in xdr_buf where XDR'd ACL begins | |
84 | * @inode: inode of file whose ACL this is | |
85 | * @acl: posix_acl to encode | |
86 | * @encode_entries: whether to encode ACEs as well | |
87 | * @typeflag: ACL type: NFS_ACL_DEFAULT or zero | |
88 | * | |
89 | * Returns size of encoded ACL in bytes or a negative errno value. | |
90 | */ | |
91 | int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode, | |
92 | struct posix_acl *acl, int encode_entries, int typeflag) | |
a257cdd0 AG |
93 | { |
94 | int entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0; | |
95 | struct nfsacl_encode_desc nfsacl_desc = { | |
96 | .desc = { | |
97 | .elem_size = 12, | |
98 | .array_len = encode_entries ? entries : 0, | |
99 | .xcode = xdr_nfsace_encode, | |
100 | }, | |
101 | .acl = acl, | |
102 | .typeflag = typeflag, | |
103 | .uid = inode->i_uid, | |
104 | .gid = inode->i_gid, | |
105 | }; | |
f61f6da0 | 106 | struct nfsacl_simple_acl aclbuf; |
a257cdd0 AG |
107 | int err; |
108 | ||
109 | if (entries > NFS_ACL_MAX_ENTRIES || | |
110 | xdr_encode_word(buf, base, entries)) | |
111 | return -EINVAL; | |
22c1ea44 | 112 | if (encode_entries && acl && acl->a_count == 3) { |
f61f6da0 CL |
113 | struct posix_acl *acl2 = &aclbuf.acl; |
114 | ||
115 | /* Avoid the use of posix_acl_alloc(). nfsacl_encode() is | |
116 | * invoked in contexts where a memory allocation failure is | |
117 | * fatal. Fortunately this fake ACL is small enough to | |
118 | * construct on the stack. */ | |
f61f6da0 CL |
119 | posix_acl_init(acl2, 4); |
120 | ||
22c1ea44 AG |
121 | /* Insert entries in canonical order: other orders seem |
122 | to confuse Solaris VxFS. */ | |
123 | acl2->a_entries[0] = acl->a_entries[0]; /* ACL_USER_OBJ */ | |
124 | acl2->a_entries[1] = acl->a_entries[1]; /* ACL_GROUP_OBJ */ | |
125 | acl2->a_entries[2] = acl->a_entries[1]; /* ACL_MASK */ | |
126 | acl2->a_entries[2].e_tag = ACL_MASK; | |
127 | acl2->a_entries[3] = acl->a_entries[2]; /* ACL_OTHER */ | |
128 | nfsacl_desc.acl = acl2; | |
129 | } | |
a257cdd0 AG |
130 | err = xdr_encode_array2(buf, base + 4, &nfsacl_desc.desc); |
131 | if (!err) | |
132 | err = 8 + nfsacl_desc.desc.elem_size * | |
133 | nfsacl_desc.desc.array_len; | |
134 | return err; | |
135 | } | |
57b696fb | 136 | EXPORT_SYMBOL_GPL(nfsacl_encode); |
a257cdd0 AG |
137 | |
138 | struct nfsacl_decode_desc { | |
139 | struct xdr_array2_desc desc; | |
140 | unsigned int count; | |
141 | struct posix_acl *acl; | |
142 | }; | |
143 | ||
144 | static int | |
145 | xdr_nfsace_decode(struct xdr_array2_desc *desc, void *elem) | |
146 | { | |
147 | struct nfsacl_decode_desc *nfsacl_desc = | |
148 | (struct nfsacl_decode_desc *) desc; | |
83bbe2ef | 149 | __be32 *p = elem; |
a257cdd0 | 150 | struct posix_acl_entry *entry; |
ddca4e17 | 151 | unsigned int id; |
a257cdd0 AG |
152 | |
153 | if (!nfsacl_desc->acl) { | |
154 | if (desc->array_len > NFS_ACL_MAX_ENTRIES) | |
155 | return -EINVAL; | |
156 | nfsacl_desc->acl = posix_acl_alloc(desc->array_len, GFP_KERNEL); | |
157 | if (!nfsacl_desc->acl) | |
158 | return -ENOMEM; | |
159 | nfsacl_desc->count = 0; | |
160 | } | |
161 | ||
162 | entry = &nfsacl_desc->acl->a_entries[nfsacl_desc->count++]; | |
163 | entry->e_tag = ntohl(*p++) & ~NFS_ACL_DEFAULT; | |
ddca4e17 | 164 | id = ntohl(*p++); |
a257cdd0 AG |
165 | entry->e_perm = ntohl(*p++); |
166 | ||
167 | switch(entry->e_tag) { | |
a257cdd0 | 168 | case ACL_USER: |
ddca4e17 EB |
169 | entry->e_uid = make_kuid(&init_user_ns, id); |
170 | if (!uid_valid(entry->e_uid)) | |
171 | return -EINVAL; | |
172 | break; | |
a257cdd0 | 173 | case ACL_GROUP: |
ddca4e17 EB |
174 | entry->e_gid = make_kgid(&init_user_ns, id); |
175 | if (!gid_valid(entry->e_gid)) | |
176 | return -EINVAL; | |
177 | break; | |
178 | case ACL_USER_OBJ: | |
179 | case ACL_GROUP_OBJ: | |
a257cdd0 AG |
180 | case ACL_OTHER: |
181 | if (entry->e_perm & ~S_IRWXO) | |
182 | return -EINVAL; | |
183 | break; | |
184 | case ACL_MASK: | |
25985edc | 185 | /* Solaris sometimes sets additional bits in the mask */ |
a257cdd0 AG |
186 | entry->e_perm &= S_IRWXO; |
187 | break; | |
188 | default: | |
189 | return -EINVAL; | |
190 | } | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
195 | static int | |
196 | cmp_acl_entry(const void *x, const void *y) | |
197 | { | |
198 | const struct posix_acl_entry *a = x, *b = y; | |
199 | ||
200 | if (a->e_tag != b->e_tag) | |
201 | return a->e_tag - b->e_tag; | |
ddca4e17 EB |
202 | else if ((a->e_tag == ACL_USER) && uid_gt(a->e_uid, b->e_uid)) |
203 | return 1; | |
204 | else if ((a->e_tag == ACL_USER) && uid_lt(a->e_uid, b->e_uid)) | |
205 | return -1; | |
206 | else if ((a->e_tag == ACL_GROUP) && gid_gt(a->e_gid, b->e_gid)) | |
a257cdd0 | 207 | return 1; |
ddca4e17 | 208 | else if ((a->e_tag == ACL_GROUP) && gid_lt(a->e_gid, b->e_gid)) |
a257cdd0 AG |
209 | return -1; |
210 | else | |
211 | return 0; | |
212 | } | |
213 | ||
214 | /* | |
215 | * Convert from a Solaris ACL to a POSIX 1003.1e draft 17 ACL. | |
216 | */ | |
217 | static int | |
218 | posix_acl_from_nfsacl(struct posix_acl *acl) | |
219 | { | |
220 | struct posix_acl_entry *pa, *pe, | |
221 | *group_obj = NULL, *mask = NULL; | |
222 | ||
223 | if (!acl) | |
224 | return 0; | |
225 | ||
226 | sort(acl->a_entries, acl->a_count, sizeof(struct posix_acl_entry), | |
227 | cmp_acl_entry, NULL); | |
228 | ||
ddca4e17 | 229 | /* Find the ACL_GROUP_OBJ and ACL_MASK entries. */ |
a257cdd0 AG |
230 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
231 | switch(pa->e_tag) { | |
232 | case ACL_USER_OBJ: | |
a257cdd0 AG |
233 | break; |
234 | case ACL_GROUP_OBJ: | |
a257cdd0 AG |
235 | group_obj = pa; |
236 | break; | |
237 | case ACL_MASK: | |
238 | mask = pa; | |
239 | /* fall through */ | |
240 | case ACL_OTHER: | |
a257cdd0 AG |
241 | break; |
242 | } | |
243 | } | |
244 | if (acl->a_count == 4 && group_obj && mask && | |
245 | mask->e_perm == group_obj->e_perm) { | |
246 | /* remove bogus ACL_MASK entry */ | |
247 | memmove(mask, mask+1, (3 - (mask - acl->a_entries)) * | |
248 | sizeof(struct posix_acl_entry)); | |
249 | acl->a_count = 3; | |
250 | } | |
251 | return 0; | |
252 | } | |
253 | ||
731f3f48 CL |
254 | /** |
255 | * nfsacl_decode - Decode an NFSv3 ACL | |
256 | * | |
257 | * @buf: xdr_buf containing XDR'd ACL data to decode | |
258 | * @base: byte offset in xdr_buf where XDR'd ACL begins | |
259 | * @aclcnt: count of ACEs in decoded posix_acl | |
260 | * @pacl: buffer in which to place decoded posix_acl | |
261 | * | |
262 | * Returns the length of the decoded ACL in bytes, or a negative errno value. | |
263 | */ | |
264 | int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt, | |
265 | struct posix_acl **pacl) | |
a257cdd0 AG |
266 | { |
267 | struct nfsacl_decode_desc nfsacl_desc = { | |
268 | .desc = { | |
269 | .elem_size = 12, | |
270 | .xcode = pacl ? xdr_nfsace_decode : NULL, | |
271 | }, | |
272 | }; | |
273 | u32 entries; | |
274 | int err; | |
275 | ||
276 | if (xdr_decode_word(buf, base, &entries) || | |
277 | entries > NFS_ACL_MAX_ENTRIES) | |
278 | return -EINVAL; | |
58fcb8df | 279 | nfsacl_desc.desc.array_maxlen = entries; |
a257cdd0 AG |
280 | err = xdr_decode_array2(buf, base + 4, &nfsacl_desc.desc); |
281 | if (err) | |
282 | return err; | |
283 | if (pacl) { | |
284 | if (entries != nfsacl_desc.desc.array_len || | |
285 | posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) { | |
286 | posix_acl_release(nfsacl_desc.acl); | |
287 | return -EINVAL; | |
288 | } | |
289 | *pacl = nfsacl_desc.acl; | |
290 | } | |
291 | if (aclcnt) | |
292 | *aclcnt = entries; | |
293 | return 8 + nfsacl_desc.desc.elem_size * | |
294 | nfsacl_desc.desc.array_len; | |
295 | } | |
57b696fb | 296 | EXPORT_SYMBOL_GPL(nfsacl_decode); |