xref: /openbmc/linux/crypto/algif_hash.c (revision bc5aa3a0) 
1 /*
2  * algif_hash: User-space interface for hash algorithms
3  *
4  * This file provides the user-space API for hash algorithms.
5  *
6  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by the Free
10  * Software Foundation; either version 2 of the License, or (at your option)
11  * any later version.
12  *
13  */
14 
15 #include <crypto/hash.h>
16 #include <crypto/if_alg.h>
17 #include <linux/init.h>
18 #include <linux/kernel.h>
19 #include <linux/mm.h>
20 #include <linux/module.h>
21 #include <linux/net.h>
22 #include <net/sock.h>
23 
24 struct hash_ctx {
25 	struct af_alg_sgl sgl;
26 
27 	u8 *result;
28 
29 	struct af_alg_completion completion;
30 
31 	unsigned int len;
32 	bool more;
33 
34 	struct ahash_request req;
35 };
36 
37 struct algif_hash_tfm {
38 	struct crypto_ahash *hash;
39 	bool has_key;
40 };
41 
42 static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
43 			size_t ignored)
44 {
45 	int limit = ALG_MAX_PAGES * PAGE_SIZE;
46 	struct sock *sk = sock->sk;
47 	struct alg_sock *ask = alg_sk(sk);
48 	struct hash_ctx *ctx = ask->private;
49 	long copied = 0;
50 	int err;
51 
52 	if (limit > sk->sk_sndbuf)
53 		limit = sk->sk_sndbuf;
54 
55 	lock_sock(sk);
56 	if (!ctx->more) {
57 		err = af_alg_wait_for_completion(crypto_ahash_init(&ctx->req),
58 						&ctx->completion);
59 		if (err)
60 			goto unlock;
61 	}
62 
63 	ctx->more = 0;
64 
65 	while (msg_data_left(msg)) {
66 		int len = msg_data_left(msg);
67 
68 		if (len > limit)
69 			len = limit;
70 
71 		len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len);
72 		if (len < 0) {
73 			err = copied ? 0 : len;
74 			goto unlock;
75 		}
76 
77 		ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);
78 
79 		err = af_alg_wait_for_completion(crypto_ahash_update(&ctx->req),
80 						 &ctx->completion);
81 		af_alg_free_sg(&ctx->sgl);
82 		if (err)
83 			goto unlock;
84 
85 		copied += len;
86 		iov_iter_advance(&msg->msg_iter, len);
87 	}
88 
89 	err = 0;
90 
91 	ctx->more = msg->msg_flags & MSG_MORE;
92 	if (!ctx->more) {
93 		ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
94 		err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
95 						 &ctx->completion);
96 	}
97 
98 unlock:
99 	release_sock(sk);
100 
101 	return err ?: copied;
102 }
103 
104 static ssize_t hash_sendpage(struct socket *sock, struct page *page,
105 			     int offset, size_t size, int flags)
106 {
107 	struct sock *sk = sock->sk;
108 	struct alg_sock *ask = alg_sk(sk);
109 	struct hash_ctx *ctx = ask->private;
110 	int err;
111 
112 	if (flags & MSG_SENDPAGE_NOTLAST)
113 		flags |= MSG_MORE;
114 
115 	lock_sock(sk);
116 	sg_init_table(ctx->sgl.sg, 1);
117 	sg_set_page(ctx->sgl.sg, page, size, offset);
118 
119 	ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);
120 
121 	if (!(flags & MSG_MORE)) {
122 		if (ctx->more)
123 			err = crypto_ahash_finup(&ctx->req);
124 		else
125 			err = crypto_ahash_digest(&ctx->req);
126 	} else {
127 		if (!ctx->more) {
128 			err = crypto_ahash_init(&ctx->req);
129 			err = af_alg_wait_for_completion(err, &ctx->completion);
130 			if (err)
131 				goto unlock;
132 		}
133 
134 		err = crypto_ahash_update(&ctx->req);
135 	}
136 
137 	err = af_alg_wait_for_completion(err, &ctx->completion);
138 	if (err)
139 		goto unlock;
140 
141 	ctx->more = flags & MSG_MORE;
142 
143 unlock:
144 	release_sock(sk);
145 
146 	return err ?: size;
147 }
148 
149 static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
150 			int flags)
151 {
152 	struct sock *sk = sock->sk;
153 	struct alg_sock *ask = alg_sk(sk);
154 	struct hash_ctx *ctx = ask->private;
155 	unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
156 	int err;
157 
158 	if (len > ds)
159 		len = ds;
160 	else if (len < ds)
161 		msg->msg_flags |= MSG_TRUNC;
162 
163 	lock_sock(sk);
164 	if (ctx->more) {
165 		ctx->more = 0;
166 		ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
167 		err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
168 						 &ctx->completion);
169 		if (err)
170 			goto unlock;
171 	}
172 
173 	err = memcpy_to_msg(msg, ctx->result, len);
174 
175 unlock:
176 	release_sock(sk);
177 
178 	return err ?: len;
179 }
180 
181 static int hash_accept(struct socket *sock, struct socket *newsock, int flags)
182 {
183 	struct sock *sk = sock->sk;
184 	struct alg_sock *ask = alg_sk(sk);
185 	struct hash_ctx *ctx = ask->private;
186 	struct ahash_request *req = &ctx->req;
187 	char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req))];
188 	struct sock *sk2;
189 	struct alg_sock *ask2;
190 	struct hash_ctx *ctx2;
191 	bool more;
192 	int err;
193 
194 	lock_sock(sk);
195 	more = ctx->more;
196 	err = more ? crypto_ahash_export(req, state) : 0;
197 	release_sock(sk);
198 
199 	if (err)
200 		return err;
201 
202 	err = af_alg_accept(ask->parent, newsock);
203 	if (err)
204 		return err;
205 
206 	sk2 = newsock->sk;
207 	ask2 = alg_sk(sk2);
208 	ctx2 = ask2->private;
209 	ctx2->more = more;
210 
211 	if (!more)
212 		return err;
213 
214 	err = crypto_ahash_import(&ctx2->req, state);
215 	if (err) {
216 		sock_orphan(sk2);
217 		sock_put(sk2);
218 	}
219 
220 	return err;
221 }
222 
223 static struct proto_ops algif_hash_ops = {
224 	.family		=	PF_ALG,
225 
226 	.connect	=	sock_no_connect,
227 	.socketpair	=	sock_no_socketpair,
228 	.getname	=	sock_no_getname,
229 	.ioctl		=	sock_no_ioctl,
230 	.listen		=	sock_no_listen,
231 	.shutdown	=	sock_no_shutdown,
232 	.getsockopt	=	sock_no_getsockopt,
233 	.mmap		=	sock_no_mmap,
234 	.bind		=	sock_no_bind,
235 	.setsockopt	=	sock_no_setsockopt,
236 	.poll		=	sock_no_poll,
237 
238 	.release	=	af_alg_release,
239 	.sendmsg	=	hash_sendmsg,
240 	.sendpage	=	hash_sendpage,
241 	.recvmsg	=	hash_recvmsg,
242 	.accept		=	hash_accept,
243 };
244 
245 static int hash_check_key(struct socket *sock)
246 {
247 	int err = 0;
248 	struct sock *psk;
249 	struct alg_sock *pask;
250 	struct algif_hash_tfm *tfm;
251 	struct sock *sk = sock->sk;
252 	struct alg_sock *ask = alg_sk(sk);
253 
254 	lock_sock(sk);
255 	if (ask->refcnt)
256 		goto unlock_child;
257 
258 	psk = ask->parent;
259 	pask = alg_sk(ask->parent);
260 	tfm = pask->private;
261 
262 	err = -ENOKEY;
263 	lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
264 	if (!tfm->has_key)
265 		goto unlock;
266 
267 	if (!pask->refcnt++)
268 		sock_hold(psk);
269 
270 	ask->refcnt = 1;
271 	sock_put(psk);
272 
273 	err = 0;
274 
275 unlock:
276 	release_sock(psk);
277 unlock_child:
278 	release_sock(sk);
279 
280 	return err;
281 }
282 
283 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
284 			      size_t size)
285 {
286 	int err;
287 
288 	err = hash_check_key(sock);
289 	if (err)
290 		return err;
291 
292 	return hash_sendmsg(sock, msg, size);
293 }
294 
295 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page,
296 				   int offset, size_t size, int flags)
297 {
298 	int err;
299 
300 	err = hash_check_key(sock);
301 	if (err)
302 		return err;
303 
304 	return hash_sendpage(sock, page, offset, size, flags);
305 }
306 
307 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
308 			      size_t ignored, int flags)
309 {
310 	int err;
311 
312 	err = hash_check_key(sock);
313 	if (err)
314 		return err;
315 
316 	return hash_recvmsg(sock, msg, ignored, flags);
317 }
318 
319 static int hash_accept_nokey(struct socket *sock, struct socket *newsock,
320 			     int flags)
321 {
322 	int err;
323 
324 	err = hash_check_key(sock);
325 	if (err)
326 		return err;
327 
328 	return hash_accept(sock, newsock, flags);
329 }
330 
331 static struct proto_ops algif_hash_ops_nokey = {
332 	.family		=	PF_ALG,
333 
334 	.connect	=	sock_no_connect,
335 	.socketpair	=	sock_no_socketpair,
336 	.getname	=	sock_no_getname,
337 	.ioctl		=	sock_no_ioctl,
338 	.listen		=	sock_no_listen,
339 	.shutdown	=	sock_no_shutdown,
340 	.getsockopt	=	sock_no_getsockopt,
341 	.mmap		=	sock_no_mmap,
342 	.bind		=	sock_no_bind,
343 	.setsockopt	=	sock_no_setsockopt,
344 	.poll		=	sock_no_poll,
345 
346 	.release	=	af_alg_release,
347 	.sendmsg	=	hash_sendmsg_nokey,
348 	.sendpage	=	hash_sendpage_nokey,
349 	.recvmsg	=	hash_recvmsg_nokey,
350 	.accept		=	hash_accept_nokey,
351 };
352 
353 static void *hash_bind(const char *name, u32 type, u32 mask)
354 {
355 	struct algif_hash_tfm *tfm;
356 	struct crypto_ahash *hash;
357 
358 	tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
359 	if (!tfm)
360 		return ERR_PTR(-ENOMEM);
361 
362 	hash = crypto_alloc_ahash(name, type, mask);
363 	if (IS_ERR(hash)) {
364 		kfree(tfm);
365 		return ERR_CAST(hash);
366 	}
367 
368 	tfm->hash = hash;
369 
370 	return tfm;
371 }
372 
373 static void hash_release(void *private)
374 {
375 	struct algif_hash_tfm *tfm = private;
376 
377 	crypto_free_ahash(tfm->hash);
378 	kfree(tfm);
379 }
380 
381 static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
382 {
383 	struct algif_hash_tfm *tfm = private;
384 	int err;
385 
386 	err = crypto_ahash_setkey(tfm->hash, key, keylen);
387 	tfm->has_key = !err;
388 
389 	return err;
390 }
391 
392 static void hash_sock_destruct(struct sock *sk)
393 {
394 	struct alg_sock *ask = alg_sk(sk);
395 	struct hash_ctx *ctx = ask->private;
396 
397 	sock_kzfree_s(sk, ctx->result,
398 		      crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
399 	sock_kfree_s(sk, ctx, ctx->len);
400 	af_alg_release_parent(sk);
401 }
402 
403 static int hash_accept_parent_nokey(void *private, struct sock *sk)
404 {
405 	struct hash_ctx *ctx;
406 	struct alg_sock *ask = alg_sk(sk);
407 	struct algif_hash_tfm *tfm = private;
408 	struct crypto_ahash *hash = tfm->hash;
409 	unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash);
410 	unsigned ds = crypto_ahash_digestsize(hash);
411 
412 	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
413 	if (!ctx)
414 		return -ENOMEM;
415 
416 	ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
417 	if (!ctx->result) {
418 		sock_kfree_s(sk, ctx, len);
419 		return -ENOMEM;
420 	}
421 
422 	memset(ctx->result, 0, ds);
423 
424 	ctx->len = len;
425 	ctx->more = 0;
426 	af_alg_init_completion(&ctx->completion);
427 
428 	ask->private = ctx;
429 
430 	ahash_request_set_tfm(&ctx->req, hash);
431 	ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
432 				   af_alg_complete, &ctx->completion);
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 algif_hash_tfm *tfm = private;
442 
443 	if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash))
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_LICENSE("GPL");
475