1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * algif_hash: User-space interface for hash algorithms
4 *
5 * This file provides the user-space API for hash algorithms.
6 *
7 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
8 */
9
10 #include <crypto/hash.h>
11 #include <crypto/if_alg.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/module.h>
16 #include <linux/net.h>
17 #include <net/sock.h>
18
19 struct hash_ctx {
20 struct af_alg_sgl sgl;
21
22 u8 *result;
23
24 struct crypto_wait wait;
25
26 unsigned int len;
27 bool more;
28
29 struct ahash_request req;
30 };
31
32 static int hash_alloc_result(struct sock *sk, struct hash_ctx *ctx)
33 {
34 unsigned ds;
35
36 if (ctx->result)
37 return 0;
38
39 ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
40
41 ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
42 if (!ctx->result)
43 return -ENOMEM;
44
45 memset(ctx->result, 0, ds);
46
47 return 0;
48 }
49
50 static void hash_free_result(struct sock *sk, struct hash_ctx *ctx)
51 {
52 unsigned ds;
53
54 if (!ctx->result)
55 return;
56
57 ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
58
59 sock_kzfree_s(sk, ctx->result, ds);
60 ctx->result = NULL;
61 }
62
63 static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
64 size_t ignored)
65 {
66 struct sock *sk = sock->sk;
67 struct alg_sock *ask = alg_sk(sk);
68 struct hash_ctx *ctx = ask->private;
69 ssize_t copied = 0;
70 size_t len, max_pages, npages;
71 bool continuing, need_init = false;
72 int err;
73
74 max_pages = min_t(size_t, ALG_MAX_PAGES,
75 DIV_ROUND_UP(sk->sk_sndbuf, PAGE_SIZE));
76
77 lock_sock(sk);
78 continuing = ctx->more;
79
80 if (!continuing) {
81 /* Discard a previous request that wasn't marked MSG_MORE. */
82 hash_free_result(sk, ctx);
83 if (!msg_data_left(msg))
84 goto done; /* Zero-length; don't start new req */
85 need_init = true;
86 } else if (!msg_data_left(msg)) {
87 /*
88 * No data - finalise the prev req if MSG_MORE so any error
89 * comes out here.
90 */
91 if (!(msg->msg_flags & MSG_MORE)) {
92 err = hash_alloc_result(sk, ctx);
93 if (err)
94 goto unlock_free_result;
95 ahash_request_set_crypt(&ctx->req, NULL,
96 ctx->result, 0);
97 err = crypto_wait_req(crypto_ahash_final(&ctx->req),
98 &ctx->wait);
99 if (err)
100 goto unlock_free_result;
101 }
102 goto done_more;
103 }
104
105 while (msg_data_left(msg)) {
106 ctx->sgl.sgt.sgl = ctx->sgl.sgl;
107 ctx->sgl.sgt.nents = 0;
108 ctx->sgl.sgt.orig_nents = 0;
109
110 err = -EIO;
111 npages = iov_iter_npages(&msg->msg_iter, max_pages);
112 if (npages == 0)
113 goto unlock_free;
114
115 sg_init_table(ctx->sgl.sgl, npages);
116
117 ctx->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter);
118
119 err = extract_iter_to_sg(&msg->msg_iter, LONG_MAX,
120 &ctx->sgl.sgt, npages, 0);
121 if (err < 0)
122 goto unlock_free;
123 len = err;
124 sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents - 1);
125
126 if (!msg_data_left(msg)) {
127 err = hash_alloc_result(sk, ctx);
128 if (err)
129 goto unlock_free;
130 }
131
132 ahash_request_set_crypt(&ctx->req, ctx->sgl.sgt.sgl,
133 ctx->result, len);
134
135 if (!msg_data_left(msg) && !continuing &&
136 !(msg->msg_flags & MSG_MORE)) {
137 err = crypto_ahash_digest(&ctx->req);
138 } else {
139 if (need_init) {
140 err = crypto_wait_req(
141 crypto_ahash_init(&ctx->req),
142 &ctx->wait);
143 if (err)
144 goto unlock_free;
145 need_init = false;
146 }
147
148 if (msg_data_left(msg) || (msg->msg_flags & MSG_MORE))
149 err = crypto_ahash_update(&ctx->req);
150 else
151 err = crypto_ahash_finup(&ctx->req);
152 continuing = true;
153 }
154
155 err = crypto_wait_req(err, &ctx->wait);
156 if (err)
157 goto unlock_free;
158
159 copied += len;
160 af_alg_free_sg(&ctx->sgl);
161 }
162
163 done_more:
164 ctx->more = msg->msg_flags & MSG_MORE;
165 done:
166 err = 0;
167 unlock:
168 release_sock(sk);
169 return copied ?: err;
170
171 unlock_free:
172 af_alg_free_sg(&ctx->sgl);
173 unlock_free_result:
174 hash_free_result(sk, ctx);
175 ctx->more = false;
176 goto unlock;
177 }
178
179 static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
180 int flags)
181 {
182 struct sock *sk = sock->sk;
183 struct alg_sock *ask = alg_sk(sk);
184 struct hash_ctx *ctx = ask->private;
185 unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
186 bool result;
187 int err;
188
189 if (len > ds)
190 len = ds;
191 else if (len < ds)
192 msg->msg_flags |= MSG_TRUNC;
193
194 lock_sock(sk);
195 result = ctx->result;
196 err = hash_alloc_result(sk, ctx);
197 if (err)
198 goto unlock;
199
200 ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
201
202 if (!result && !ctx->more) {
203 err = crypto_wait_req(crypto_ahash_init(&ctx->req),
204 &ctx->wait);
205 if (err)
206 goto unlock;
207 }
208
209 if (!result || ctx->more) {
210 ctx->more = false;
211 err = crypto_wait_req(crypto_ahash_final(&ctx->req),
212 &ctx->wait);
213 if (err)
214 goto unlock;
215 }
216
217 err = memcpy_to_msg(msg, ctx->result, len);
218
219 unlock:
220 hash_free_result(sk, ctx);
221 release_sock(sk);
222
223 return err ?: len;
224 }
225
226 static int hash_accept(struct socket *sock, struct socket *newsock,
227 struct proto_accept_arg *arg)
228 {
229 struct sock *sk = sock->sk;
230 struct alg_sock *ask = alg_sk(sk);
231 struct hash_ctx *ctx = ask->private;
232 struct ahash_request *req = &ctx->req;
233 struct crypto_ahash *tfm;
234 struct sock *sk2;
235 struct alg_sock *ask2;
236 struct hash_ctx *ctx2;
237 char *state;
238 bool more;
239 int err;
240
241 tfm = crypto_ahash_reqtfm(req);
242 state = kmalloc(crypto_ahash_statesize(tfm), GFP_KERNEL);
243 err = -ENOMEM;
244 if (!state)
245 goto out;
246
247 lock_sock(sk);
248 more = ctx->more;
249 err = more ? crypto_ahash_export(req, state) : 0;
250 release_sock(sk);
251
252 if (err)
253 goto out_free_state;
254
255 err = af_alg_accept(ask->parent, newsock, arg);
256 if (err)
257 goto out_free_state;
258
259 sk2 = newsock->sk;
260 ask2 = alg_sk(sk2);
261 ctx2 = ask2->private;
262 ctx2->more = more;
263
264 if (!more)
265 goto out_free_state;
266
267 err = crypto_ahash_import(&ctx2->req, state);
268 if (err) {
269 sock_orphan(sk2);
270 sock_put(sk2);
271 }
272
273 out_free_state:
274 kfree_sensitive(state);
275
276 out:
277 return err;
278 }
279
280 static struct proto_ops algif_hash_ops = {
281 .family = PF_ALG,
282
283 .connect = sock_no_connect,
284 .socketpair = sock_no_socketpair,
285 .getname = sock_no_getname,
286 .ioctl = sock_no_ioctl,
287 .listen = sock_no_listen,
288 .shutdown = sock_no_shutdown,
289 .mmap = sock_no_mmap,
290 .bind = sock_no_bind,
291
292 .release = af_alg_release,
293 .sendmsg = hash_sendmsg,
294 .recvmsg = hash_recvmsg,
295 .accept = hash_accept,
296 };
297
298 static int hash_check_key(struct socket *sock)
299 {
300 int err = 0;
301 struct sock *psk;
302 struct alg_sock *pask;
303 struct crypto_ahash *tfm;
304 struct sock *sk = sock->sk;
305 struct alg_sock *ask = alg_sk(sk);
306
307 lock_sock(sk);
308 if (!atomic_read(&ask->nokey_refcnt))
309 goto unlock_child;
310
311 psk = ask->parent;
312 pask = alg_sk(ask->parent);
313 tfm = pask->private;
314
315 err = -ENOKEY;
316 lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
317 if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
318 goto unlock;
319
320 atomic_dec(&pask->nokey_refcnt);
321 atomic_set(&ask->nokey_refcnt, 0);
322
323 err = 0;
324
325 unlock:
326 release_sock(psk);
327 unlock_child:
328 release_sock(sk);
329
330 return err;
331 }
332
333 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
334 size_t size)
335 {
336 int err;
337
338 err = hash_check_key(sock);
339 if (err)
340 return err;
341
342 return hash_sendmsg(sock, msg, size);
343 }
344
345 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
346 size_t ignored, int flags)
347 {
348 int err;
349
350 err = hash_check_key(sock);
351 if (err)
352 return err;
353
354 return hash_recvmsg(sock, msg, ignored, flags);
355 }
356
357 static int hash_accept_nokey(struct socket *sock, struct socket *newsock,
358 struct proto_accept_arg *arg)
359 {
360 int err;
361
362 err = hash_check_key(sock);
363 if (err)
364 return err;
365
366 return hash_accept(sock, newsock, arg);
367 }
368
369 static struct proto_ops algif_hash_ops_nokey = {
370 .family = PF_ALG,
371
372 .connect = sock_no_connect,
373 .socketpair = sock_no_socketpair,
374 .getname = sock_no_getname,
375 .ioctl = sock_no_ioctl,
376 .listen = sock_no_listen,
377 .shutdown = sock_no_shutdown,
378 .mmap = sock_no_mmap,
379 .bind = sock_no_bind,
380
381 .release = af_alg_release,
382 .sendmsg = hash_sendmsg_nokey,
383 .recvmsg = hash_recvmsg_nokey,
384 .accept = hash_accept_nokey,
385 };
386
387 static void *hash_bind(const char *name, u32 type, u32 mask)
388 {
389 return crypto_alloc_ahash(name, type, mask);
390 }
391
392 static void hash_release(void *private)
393 {
394 crypto_free_ahash(private);
395 }
396
397 static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
398 {
399 return crypto_ahash_setkey(private, key, keylen);
400 }
401
402 static void hash_sock_destruct(struct sock *sk)
403 {
404 struct alg_sock *ask = alg_sk(sk);
405 struct hash_ctx *ctx = ask->private;
406
407 hash_free_result(sk, ctx);
408 sock_kfree_s(sk, ctx, ctx->len);
409 af_alg_release_parent(sk);
410 }
411
412 static int hash_accept_parent_nokey(void *private, struct sock *sk)
413 {
414 struct crypto_ahash *tfm = private;
415 struct alg_sock *ask = alg_sk(sk);
416 struct hash_ctx *ctx;
417 unsigned int len = sizeof(*ctx) + crypto_ahash_reqsize(tfm);
418
419 ctx = sock_kmalloc(sk, len, GFP_KERNEL);
420 if (!ctx)
421 return -ENOMEM;
422
423 ctx->result = NULL;
424 ctx->len = len;
425 ctx->more = false;
426 crypto_init_wait(&ctx->wait);
427
428 ask->private = ctx;
429
430 ahash_request_set_tfm(&ctx->req, tfm);
431 ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
432 crypto_req_done, &ctx->wait);
433
434 sk->sk_destruct = hash_sock_destruct;
435
436 return 0;
437 }
438
439 static int hash_accept_parent(void *private, struct sock *sk)
440 {
441 struct crypto_ahash *tfm = private;
442
443 if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
444 return -ENOKEY;
445
446 return hash_accept_parent_nokey(private, sk);
447 }
448
449 static const struct af_alg_type algif_type_hash = {
450 .bind = hash_bind,
451 .release = hash_release,
452 .setkey = hash_setkey,
453 .accept = hash_accept_parent,
454 .accept_nokey = hash_accept_parent_nokey,
455 .ops = &algif_hash_ops,
456 .ops_nokey = &algif_hash_ops_nokey,
457 .name = "hash",
458 .owner = THIS_MODULE
459 };
460
461 static int __init algif_hash_init(void)
462 {
463 return af_alg_register_type(&algif_type_hash);
464 }
465
466 static void __exit algif_hash_exit(void)
467 {
468 int err = af_alg_unregister_type(&algif_type_hash);
469 BUG_ON(err);
470 }
471
472 module_init(algif_hash_init);
473 module_exit(algif_hash_exit);
474 MODULE_DESCRIPTION("Userspace interface for hash algorithms");
475 MODULE_LICENSE("GPL");
476
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.