Commit | Line | Data |
---|---|---|
09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
a257cdd0 AG |
2 | /* |
3 | * fs/nfs_common/nfsacl.c | |
4 | * | |
5 | * Copyright (C) 2002-2003 Andreas Gruenbacher <agruen@suse.de> | |
6 | */ | |
7 | ||
8 | /* | |
9 | * The Solaris nfsacl protocol represents some ACLs slightly differently | |
10 | * than POSIX 1003.1e draft 17 does (and we do): | |
11 | * | |
12 | * - Minimal ACLs always have an ACL_MASK entry, so they have | |
13 | * four instead of three entries. | |
14 | * - The ACL_MASK entry in such minimal ACLs always has the same | |
15 | * permissions as the ACL_GROUP_OBJ entry. (In extended ACLs | |
16 | * the ACL_MASK and ACL_GROUP_OBJ entries may differ.) | |
17 | * - The identifier fields of the ACL_USER_OBJ and ACL_GROUP_OBJ | |
18 | * entries contain the identifiers of the owner and owning group. | |
19 | * (In POSIX ACLs we always set them to ACL_UNDEFINED_ID). | |
20 | * - ACL entries in the kernel are kept sorted in ascending order | |
21 | * of (e_tag, e_id). Solaris ACLs are unsorted. | |
22 | */ | |
23 | ||
24 | #include <linux/module.h> | |
25 | #include <linux/fs.h> | |
5a0e3ad6 | 26 | #include <linux/gfp.h> |
a257cdd0 AG |
27 | #include <linux/sunrpc/xdr.h> |
28 | #include <linux/nfsacl.h> | |
29 | #include <linux/nfs3.h> | |
30 | #include <linux/sort.h> | |
31 | ||
32 | MODULE_LICENSE("GPL"); | |
33 | ||
a257cdd0 AG |
34 | struct nfsacl_encode_desc { |
35 | struct xdr_array2_desc desc; | |
36 | unsigned int count; | |
37 | struct posix_acl *acl; | |
38 | int typeflag; | |
ddca4e17 EB |
39 | kuid_t uid; |
40 | kgid_t gid; | |
a257cdd0 AG |
41 | }; |
42 | ||
f61f6da0 CL |
43 | struct nfsacl_simple_acl { |
44 | struct posix_acl acl; | |
45 | struct posix_acl_entry ace[4]; | |
46 | }; | |
47 | ||
a257cdd0 AG |
48 | static int |
49 | xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem) | |
50 | { | |
51 | struct nfsacl_encode_desc *nfsacl_desc = | |
52 | (struct nfsacl_encode_desc *) desc; | |
83bbe2ef | 53 | __be32 *p = elem; |
a257cdd0 | 54 | |
22c1ea44 AG |
55 | struct posix_acl_entry *entry = |
56 | &nfsacl_desc->acl->a_entries[nfsacl_desc->count++]; | |
a257cdd0 | 57 | |
22c1ea44 AG |
58 | *p++ = htonl(entry->e_tag | nfsacl_desc->typeflag); |
59 | switch(entry->e_tag) { | |
60 | case ACL_USER_OBJ: | |
ddca4e17 | 61 | *p++ = htonl(from_kuid(&init_user_ns, nfsacl_desc->uid)); |
22c1ea44 AG |
62 | break; |
63 | case ACL_GROUP_OBJ: | |
ddca4e17 | 64 | *p++ = htonl(from_kgid(&init_user_ns, nfsacl_desc->gid)); |
22c1ea44 AG |
65 | break; |
66 | case ACL_USER: | |
ddca4e17 EB |
67 | *p++ = htonl(from_kuid(&init_user_ns, entry->e_uid)); |
68 | break; | |
22c1ea44 | 69 | case ACL_GROUP: |
ddca4e17 | 70 | *p++ = htonl(from_kgid(&init_user_ns, entry->e_gid)); |
22c1ea44 AG |
71 | break; |
72 | default: /* Solaris depends on that! */ | |
73 | *p++ = 0; | |
74 | break; | |
a257cdd0 | 75 | } |
22c1ea44 | 76 | *p++ = htonl(entry->e_perm & S_IRWXO); |
a257cdd0 AG |
77 | return 0; |
78 | } | |
79 | ||
731f3f48 CL |
80 | /** |
81 | * nfsacl_encode - Encode an NFSv3 ACL | |
82 | * | |
83 | * @buf: destination xdr_buf to contain XDR encoded ACL | |
84 | * @base: byte offset in xdr_buf where XDR'd ACL begins | |
85 | * @inode: inode of file whose ACL this is | |
86 | * @acl: posix_acl to encode | |
87 | * @encode_entries: whether to encode ACEs as well | |
88 | * @typeflag: ACL type: NFS_ACL_DEFAULT or zero | |
89 | * | |
90 | * Returns size of encoded ACL in bytes or a negative errno value. | |
91 | */ | |
92 | int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode, | |
93 | struct posix_acl *acl, int encode_entries, int typeflag) | |
a257cdd0 AG |
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 | }; | |
f61f6da0 | 107 | struct nfsacl_simple_acl aclbuf; |
a257cdd0 AG |
108 | int err; |
109 | ||
110 | if (entries > NFS_ACL_MAX_ENTRIES || | |
111 | xdr_encode_word(buf, base, entries)) | |
112 | return -EINVAL; | |
22c1ea44 | 113 | if (encode_entries && acl && acl->a_count == 3) { |
f61f6da0 CL |
114 | struct posix_acl *acl2 = &aclbuf.acl; |
115 | ||
116 | /* Avoid the use of posix_acl_alloc(). nfsacl_encode() is | |
117 | * invoked in contexts where a memory allocation failure is | |
118 | * fatal. Fortunately this fake ACL is small enough to | |
119 | * construct on the stack. */ | |
f61f6da0 CL |
120 | posix_acl_init(acl2, 4); |
121 | ||
22c1ea44 AG |
122 | /* Insert entries in canonical order: other orders seem |
123 | to confuse Solaris VxFS. */ | |
124 | acl2->a_entries[0] = acl->a_entries[0]; /* ACL_USER_OBJ */ | |
125 | acl2->a_entries[1] = acl->a_entries[1]; /* ACL_GROUP_OBJ */ | |
126 | acl2->a_entries[2] = acl->a_entries[1]; /* ACL_MASK */ | |
127 | acl2->a_entries[2].e_tag = ACL_MASK; | |
128 | acl2->a_entries[3] = acl->a_entries[2]; /* ACL_OTHER */ | |
129 | nfsacl_desc.acl = acl2; | |
130 | } | |
a257cdd0 AG |
131 | err = xdr_encode_array2(buf, base + 4, &nfsacl_desc.desc); |
132 | if (!err) | |
133 | err = 8 + nfsacl_desc.desc.elem_size * | |
134 | nfsacl_desc.desc.array_len; | |
135 | return err; | |
136 | } | |
57b696fb | 137 | EXPORT_SYMBOL_GPL(nfsacl_encode); |
a257cdd0 | 138 | |
8edc0648 CL |
139 | /** |
140 | * nfs_stream_encode_acl - Encode an NFSv3 ACL | |
141 | * | |
142 | * @xdr: an xdr_stream positioned to receive an encoded ACL | |
143 | * @inode: inode of file whose ACL this is | |
144 | * @acl: posix_acl to encode | |
145 | * @encode_entries: whether to encode ACEs as well | |
146 | * @typeflag: ACL type: NFS_ACL_DEFAULT or zero | |
147 | * | |
148 | * Return values: | |
149 | * %false: The ACL could not be encoded | |
150 | * %true: @xdr is advanced to the next available position | |
151 | */ | |
152 | bool nfs_stream_encode_acl(struct xdr_stream *xdr, struct inode *inode, | |
153 | struct posix_acl *acl, int encode_entries, | |
154 | int typeflag) | |
155 | { | |
156 | const size_t elem_size = XDR_UNIT * 3; | |
157 | u32 entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0; | |
158 | struct nfsacl_encode_desc nfsacl_desc = { | |
159 | .desc = { | |
160 | .elem_size = elem_size, | |
161 | .array_len = encode_entries ? entries : 0, | |
162 | .xcode = xdr_nfsace_encode, | |
163 | }, | |
164 | .acl = acl, | |
165 | .typeflag = typeflag, | |
166 | .uid = inode->i_uid, | |
167 | .gid = inode->i_gid, | |
168 | }; | |
169 | struct nfsacl_simple_acl aclbuf; | |
170 | unsigned int base; | |
171 | int err; | |
172 | ||
173 | if (entries > NFS_ACL_MAX_ENTRIES) | |
174 | return false; | |
175 | if (xdr_stream_encode_u32(xdr, entries) < 0) | |
176 | return false; | |
177 | ||
178 | if (encode_entries && acl && acl->a_count == 3) { | |
179 | struct posix_acl *acl2 = &aclbuf.acl; | |
180 | ||
181 | /* Avoid the use of posix_acl_alloc(). nfsacl_encode() is | |
182 | * invoked in contexts where a memory allocation failure is | |
183 | * fatal. Fortunately this fake ACL is small enough to | |
184 | * construct on the stack. */ | |
185 | posix_acl_init(acl2, 4); | |
186 | ||
187 | /* Insert entries in canonical order: other orders seem | |
188 | to confuse Solaris VxFS. */ | |
189 | acl2->a_entries[0] = acl->a_entries[0]; /* ACL_USER_OBJ */ | |
190 | acl2->a_entries[1] = acl->a_entries[1]; /* ACL_GROUP_OBJ */ | |
191 | acl2->a_entries[2] = acl->a_entries[1]; /* ACL_MASK */ | |
192 | acl2->a_entries[2].e_tag = ACL_MASK; | |
193 | acl2->a_entries[3] = acl->a_entries[2]; /* ACL_OTHER */ | |
194 | nfsacl_desc.acl = acl2; | |
195 | } | |
196 | ||
197 | base = xdr_stream_pos(xdr); | |
198 | if (!xdr_reserve_space(xdr, XDR_UNIT + | |
199 | elem_size * nfsacl_desc.desc.array_len)) | |
200 | return false; | |
201 | err = xdr_encode_array2(xdr->buf, base, &nfsacl_desc.desc); | |
202 | if (err) | |
203 | return false; | |
204 | ||
205 | return true; | |
206 | } | |
207 | EXPORT_SYMBOL_GPL(nfs_stream_encode_acl); | |
208 | ||
209 | ||
a257cdd0 AG |
210 | struct nfsacl_decode_desc { |
211 | struct xdr_array2_desc desc; | |
212 | unsigned int count; | |
213 | struct posix_acl *acl; | |
214 | }; | |
215 | ||
216 | static int | |
217 | xdr_nfsace_decode(struct xdr_array2_desc *desc, void *elem) | |
218 | { | |
219 | struct nfsacl_decode_desc *nfsacl_desc = | |
220 | (struct nfsacl_decode_desc *) desc; | |
83bbe2ef | 221 | __be32 *p = elem; |
a257cdd0 | 222 | struct posix_acl_entry *entry; |
ddca4e17 | 223 | unsigned int id; |
a257cdd0 AG |
224 | |
225 | if (!nfsacl_desc->acl) { | |
226 | if (desc->array_len > NFS_ACL_MAX_ENTRIES) | |
227 | return -EINVAL; | |
228 | nfsacl_desc->acl = posix_acl_alloc(desc->array_len, GFP_KERNEL); | |
229 | if (!nfsacl_desc->acl) | |
230 | return -ENOMEM; | |
231 | nfsacl_desc->count = 0; | |
232 | } | |
233 | ||
234 | entry = &nfsacl_desc->acl->a_entries[nfsacl_desc->count++]; | |
235 | entry->e_tag = ntohl(*p++) & ~NFS_ACL_DEFAULT; | |
ddca4e17 | 236 | id = ntohl(*p++); |
a257cdd0 AG |
237 | entry->e_perm = ntohl(*p++); |
238 | ||
239 | switch(entry->e_tag) { | |
a257cdd0 | 240 | case ACL_USER: |
ddca4e17 EB |
241 | entry->e_uid = make_kuid(&init_user_ns, id); |
242 | if (!uid_valid(entry->e_uid)) | |
243 | return -EINVAL; | |
244 | break; | |
a257cdd0 | 245 | case ACL_GROUP: |
ddca4e17 EB |
246 | entry->e_gid = make_kgid(&init_user_ns, id); |
247 | if (!gid_valid(entry->e_gid)) | |
248 | return -EINVAL; | |
249 | break; | |
250 | case ACL_USER_OBJ: | |
251 | case ACL_GROUP_OBJ: | |
a257cdd0 AG |
252 | case ACL_OTHER: |
253 | if (entry->e_perm & ~S_IRWXO) | |
254 | return -EINVAL; | |
255 | break; | |
256 | case ACL_MASK: | |
25985edc | 257 | /* Solaris sometimes sets additional bits in the mask */ |
a257cdd0 AG |
258 | entry->e_perm &= S_IRWXO; |
259 | break; | |
260 | default: | |
261 | return -EINVAL; | |
262 | } | |
263 | ||
264 | return 0; | |
265 | } | |
266 | ||
267 | static int | |
268 | cmp_acl_entry(const void *x, const void *y) | |
269 | { | |
270 | const struct posix_acl_entry *a = x, *b = y; | |
271 | ||
272 | if (a->e_tag != b->e_tag) | |
273 | return a->e_tag - b->e_tag; | |
ddca4e17 EB |
274 | else if ((a->e_tag == ACL_USER) && uid_gt(a->e_uid, b->e_uid)) |
275 | return 1; | |
276 | else if ((a->e_tag == ACL_USER) && uid_lt(a->e_uid, b->e_uid)) | |
277 | return -1; | |
278 | else if ((a->e_tag == ACL_GROUP) && gid_gt(a->e_gid, b->e_gid)) | |
a257cdd0 | 279 | return 1; |
ddca4e17 | 280 | else if ((a->e_tag == ACL_GROUP) && gid_lt(a->e_gid, b->e_gid)) |
a257cdd0 AG |
281 | return -1; |
282 | else | |
283 | return 0; | |
284 | } | |
285 | ||
286 | /* | |
287 | * Convert from a Solaris ACL to a POSIX 1003.1e draft 17 ACL. | |
288 | */ | |
289 | static int | |
290 | posix_acl_from_nfsacl(struct posix_acl *acl) | |
291 | { | |
292 | struct posix_acl_entry *pa, *pe, | |
293 | *group_obj = NULL, *mask = NULL; | |
294 | ||
295 | if (!acl) | |
296 | return 0; | |
297 | ||
298 | sort(acl->a_entries, acl->a_count, sizeof(struct posix_acl_entry), | |
299 | cmp_acl_entry, NULL); | |
300 | ||
ddca4e17 | 301 | /* Find the ACL_GROUP_OBJ and ACL_MASK entries. */ |
a257cdd0 AG |
302 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
303 | switch(pa->e_tag) { | |
304 | case ACL_USER_OBJ: | |
a257cdd0 AG |
305 | break; |
306 | case ACL_GROUP_OBJ: | |
a257cdd0 AG |
307 | group_obj = pa; |
308 | break; | |
309 | case ACL_MASK: | |
310 | mask = pa; | |
df561f66 | 311 | fallthrough; |
a257cdd0 | 312 | case ACL_OTHER: |
a257cdd0 AG |
313 | break; |
314 | } | |
315 | } | |
316 | if (acl->a_count == 4 && group_obj && mask && | |
317 | mask->e_perm == group_obj->e_perm) { | |
318 | /* remove bogus ACL_MASK entry */ | |
319 | memmove(mask, mask+1, (3 - (mask - acl->a_entries)) * | |
320 | sizeof(struct posix_acl_entry)); | |
321 | acl->a_count = 3; | |
322 | } | |
323 | return 0; | |
324 | } | |
325 | ||
731f3f48 CL |
326 | /** |
327 | * nfsacl_decode - Decode an NFSv3 ACL | |
328 | * | |
329 | * @buf: xdr_buf containing XDR'd ACL data to decode | |
330 | * @base: byte offset in xdr_buf where XDR'd ACL begins | |
331 | * @aclcnt: count of ACEs in decoded posix_acl | |
332 | * @pacl: buffer in which to place decoded posix_acl | |
333 | * | |
334 | * Returns the length of the decoded ACL in bytes, or a negative errno value. | |
335 | */ | |
336 | int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt, | |
337 | struct posix_acl **pacl) | |
a257cdd0 AG |
338 | { |
339 | struct nfsacl_decode_desc nfsacl_desc = { | |
340 | .desc = { | |
341 | .elem_size = 12, | |
342 | .xcode = pacl ? xdr_nfsace_decode : NULL, | |
343 | }, | |
344 | }; | |
345 | u32 entries; | |
346 | int err; | |
347 | ||
348 | if (xdr_decode_word(buf, base, &entries) || | |
349 | entries > NFS_ACL_MAX_ENTRIES) | |
350 | return -EINVAL; | |
58fcb8df | 351 | nfsacl_desc.desc.array_maxlen = entries; |
a257cdd0 AG |
352 | err = xdr_decode_array2(buf, base + 4, &nfsacl_desc.desc); |
353 | if (err) | |
354 | return err; | |
355 | if (pacl) { | |
356 | if (entries != nfsacl_desc.desc.array_len || | |
357 | posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) { | |
358 | posix_acl_release(nfsacl_desc.acl); | |
359 | return -EINVAL; | |
360 | } | |
361 | *pacl = nfsacl_desc.acl; | |
362 | } | |
363 | if (aclcnt) | |
364 | *aclcnt = entries; | |
365 | return 8 + nfsacl_desc.desc.elem_size * | |
366 | nfsacl_desc.desc.array_len; | |
367 | } | |
57b696fb | 368 | EXPORT_SYMBOL_GPL(nfsacl_decode); |
6bb844b4 CL |
369 | |
370 | /** | |
371 | * nfs_stream_decode_acl - Decode an NFSv3 ACL | |
372 | * | |
373 | * @xdr: an xdr_stream positioned at an encoded ACL | |
374 | * @aclcnt: OUT: count of ACEs in decoded posix_acl | |
375 | * @pacl: OUT: a dynamically-allocated buffer containing the decoded posix_acl | |
376 | * | |
377 | * Return values: | |
378 | * %false: The encoded ACL is not valid | |
379 | * %true: @pacl contains a decoded ACL, and @xdr is advanced | |
380 | * | |
381 | * On a successful return, caller must release *pacl using posix_acl_release(). | |
382 | */ | |
383 | bool nfs_stream_decode_acl(struct xdr_stream *xdr, unsigned int *aclcnt, | |
384 | struct posix_acl **pacl) | |
385 | { | |
386 | const size_t elem_size = XDR_UNIT * 3; | |
387 | struct nfsacl_decode_desc nfsacl_desc = { | |
388 | .desc = { | |
389 | .elem_size = elem_size, | |
390 | .xcode = pacl ? xdr_nfsace_decode : NULL, | |
391 | }, | |
392 | }; | |
393 | unsigned int base; | |
394 | u32 entries; | |
395 | ||
396 | if (xdr_stream_decode_u32(xdr, &entries) < 0) | |
397 | return false; | |
398 | if (entries > NFS_ACL_MAX_ENTRIES) | |
399 | return false; | |
400 | ||
401 | base = xdr_stream_pos(xdr); | |
402 | if (!xdr_inline_decode(xdr, XDR_UNIT + elem_size * entries)) | |
403 | return false; | |
404 | nfsacl_desc.desc.array_maxlen = entries; | |
405 | if (xdr_decode_array2(xdr->buf, base, &nfsacl_desc.desc)) | |
406 | return false; | |
407 | ||
408 | if (pacl) { | |
409 | if (entries != nfsacl_desc.desc.array_len || | |
410 | posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) { | |
411 | posix_acl_release(nfsacl_desc.acl); | |
412 | return false; | |
413 | } | |
414 | *pacl = nfsacl_desc.acl; | |
415 | } | |
416 | if (aclcnt) | |
417 | *aclcnt = entries; | |
418 | return true; | |
419 | } | |
420 | EXPORT_SYMBOL_GPL(nfs_stream_decode_acl); |