xref: /linux/crypto/algif_hash.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
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 
hash_alloc_result(struct sock * sk,struct hash_ctx * ctx)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 
hash_free_result(struct sock * sk,struct hash_ctx * ctx)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 
hash_sendmsg(struct socket * sock,struct msghdr * msg,size_t ignored)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 
hash_recvmsg(struct socket * sock,struct msghdr * msg,size_t len,int flags)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 
hash_accept(struct socket * sock,struct socket * newsock,struct proto_accept_arg * arg)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 
hash_check_key(struct socket * sock)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 
hash_sendmsg_nokey(struct socket * sock,struct msghdr * msg,size_t size)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 
hash_recvmsg_nokey(struct socket * sock,struct msghdr * msg,size_t ignored,int flags)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 
hash_accept_nokey(struct socket * sock,struct socket * newsock,struct proto_accept_arg * arg)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 
hash_bind(const char * name,u32 type,u32 mask)387 static void *hash_bind(const char *name, u32 type, u32 mask)
388 {
389 	return crypto_alloc_ahash(name, type, mask);
390 }
391 
hash_release(void * private)392 static void hash_release(void *private)
393 {
394 	crypto_free_ahash(private);
395 }
396 
hash_setkey(void * private,const u8 * key,unsigned int keylen)397 static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
398 {
399 	return crypto_ahash_setkey(private, key, keylen);
400 }
401 
hash_sock_destruct(struct sock * sk)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 
hash_accept_parent_nokey(void * private,struct sock * sk)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 
hash_accept_parent(void * private,struct sock * sk)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 
algif_hash_init(void)461 static int __init algif_hash_init(void)
462 {
463 	return af_alg_register_type(&algif_type_hash);
464 }
465 
algif_hash_exit(void)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