xref: /openbmc/linux/net/tls/tls_main.c (revision 160b8e75) 
1 /*
2  * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
3  * Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33 
34 #include <linux/module.h>
35 
36 #include <net/tcp.h>
37 #include <net/inet_common.h>
38 #include <linux/highmem.h>
39 #include <linux/netdevice.h>
40 #include <linux/sched/signal.h>
41 
42 #include <net/tls.h>
43 
44 MODULE_AUTHOR("Mellanox Technologies");
45 MODULE_DESCRIPTION("Transport Layer Security Support");
46 MODULE_LICENSE("Dual BSD/GPL");
47 
48 enum {
49 	TLS_BASE_TX,
50 	TLS_SW_TX,
51 	TLS_NUM_CONFIG,
52 };
53 
54 static struct proto tls_prots[TLS_NUM_CONFIG];
55 
56 static inline void update_sk_prot(struct sock *sk, struct tls_context *ctx)
57 {
58 	sk->sk_prot = &tls_prots[ctx->tx_conf];
59 }
60 
61 int wait_on_pending_writer(struct sock *sk, long *timeo)
62 {
63 	int rc = 0;
64 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
65 
66 	add_wait_queue(sk_sleep(sk), &wait);
67 	while (1) {
68 		if (!*timeo) {
69 			rc = -EAGAIN;
70 			break;
71 		}
72 
73 		if (signal_pending(current)) {
74 			rc = sock_intr_errno(*timeo);
75 			break;
76 		}
77 
78 		if (sk_wait_event(sk, timeo, !sk->sk_write_pending, &wait))
79 			break;
80 	}
81 	remove_wait_queue(sk_sleep(sk), &wait);
82 	return rc;
83 }
84 
85 int tls_push_sg(struct sock *sk,
86 		struct tls_context *ctx,
87 		struct scatterlist *sg,
88 		u16 first_offset,
89 		int flags)
90 {
91 	int sendpage_flags = flags | MSG_SENDPAGE_NOTLAST;
92 	int ret = 0;
93 	struct page *p;
94 	size_t size;
95 	int offset = first_offset;
96 
97 	size = sg->length - offset;
98 	offset += sg->offset;
99 
100 	while (1) {
101 		if (sg_is_last(sg))
102 			sendpage_flags = flags;
103 
104 		/* is sending application-limited? */
105 		tcp_rate_check_app_limited(sk);
106 		p = sg_page(sg);
107 retry:
108 		ret = do_tcp_sendpages(sk, p, offset, size, sendpage_flags);
109 
110 		if (ret != size) {
111 			if (ret > 0) {
112 				offset += ret;
113 				size -= ret;
114 				goto retry;
115 			}
116 
117 			offset -= sg->offset;
118 			ctx->partially_sent_offset = offset;
119 			ctx->partially_sent_record = (void *)sg;
120 			return ret;
121 		}
122 
123 		put_page(p);
124 		sk_mem_uncharge(sk, sg->length);
125 		sg = sg_next(sg);
126 		if (!sg)
127 			break;
128 
129 		offset = sg->offset;
130 		size = sg->length;
131 	}
132 
133 	clear_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
134 
135 	return 0;
136 }
137 
138 static int tls_handle_open_record(struct sock *sk, int flags)
139 {
140 	struct tls_context *ctx = tls_get_ctx(sk);
141 
142 	if (tls_is_pending_open_record(ctx))
143 		return ctx->push_pending_record(sk, flags);
144 
145 	return 0;
146 }
147 
148 int tls_proccess_cmsg(struct sock *sk, struct msghdr *msg,
149 		      unsigned char *record_type)
150 {
151 	struct cmsghdr *cmsg;
152 	int rc = -EINVAL;
153 
154 	for_each_cmsghdr(cmsg, msg) {
155 		if (!CMSG_OK(msg, cmsg))
156 			return -EINVAL;
157 		if (cmsg->cmsg_level != SOL_TLS)
158 			continue;
159 
160 		switch (cmsg->cmsg_type) {
161 		case TLS_SET_RECORD_TYPE:
162 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(*record_type)))
163 				return -EINVAL;
164 
165 			if (msg->msg_flags & MSG_MORE)
166 				return -EINVAL;
167 
168 			rc = tls_handle_open_record(sk, msg->msg_flags);
169 			if (rc)
170 				return rc;
171 
172 			*record_type = *(unsigned char *)CMSG_DATA(cmsg);
173 			rc = 0;
174 			break;
175 		default:
176 			return -EINVAL;
177 		}
178 	}
179 
180 	return rc;
181 }
182 
183 int tls_push_pending_closed_record(struct sock *sk, struct tls_context *ctx,
184 				   int flags, long *timeo)
185 {
186 	struct scatterlist *sg;
187 	u16 offset;
188 
189 	if (!tls_is_partially_sent_record(ctx))
190 		return ctx->push_pending_record(sk, flags);
191 
192 	sg = ctx->partially_sent_record;
193 	offset = ctx->partially_sent_offset;
194 
195 	ctx->partially_sent_record = NULL;
196 	return tls_push_sg(sk, ctx, sg, offset, flags);
197 }
198 
199 static void tls_write_space(struct sock *sk)
200 {
201 	struct tls_context *ctx = tls_get_ctx(sk);
202 
203 	if (!sk->sk_write_pending && tls_is_pending_closed_record(ctx)) {
204 		gfp_t sk_allocation = sk->sk_allocation;
205 		int rc;
206 		long timeo = 0;
207 
208 		sk->sk_allocation = GFP_ATOMIC;
209 		rc = tls_push_pending_closed_record(sk, ctx,
210 						    MSG_DONTWAIT |
211 						    MSG_NOSIGNAL,
212 						    &timeo);
213 		sk->sk_allocation = sk_allocation;
214 
215 		if (rc < 0)
216 			return;
217 	}
218 
219 	ctx->sk_write_space(sk);
220 }
221 
222 static void tls_sk_proto_close(struct sock *sk, long timeout)
223 {
224 	struct tls_context *ctx = tls_get_ctx(sk);
225 	long timeo = sock_sndtimeo(sk, 0);
226 	void (*sk_proto_close)(struct sock *sk, long timeout);
227 
228 	lock_sock(sk);
229 	sk_proto_close = ctx->sk_proto_close;
230 
231 	if (ctx->tx_conf == TLS_BASE_TX) {
232 		kfree(ctx);
233 		goto skip_tx_cleanup;
234 	}
235 
236 	if (!tls_complete_pending_work(sk, ctx, 0, &timeo))
237 		tls_handle_open_record(sk, 0);
238 
239 	if (ctx->partially_sent_record) {
240 		struct scatterlist *sg = ctx->partially_sent_record;
241 
242 		while (1) {
243 			put_page(sg_page(sg));
244 			sk_mem_uncharge(sk, sg->length);
245 
246 			if (sg_is_last(sg))
247 				break;
248 			sg++;
249 		}
250 	}
251 
252 	kfree(ctx->rec_seq);
253 	kfree(ctx->iv);
254 
255 	if (ctx->tx_conf == TLS_SW_TX)
256 		tls_sw_free_tx_resources(sk);
257 
258 skip_tx_cleanup:
259 	release_sock(sk);
260 	sk_proto_close(sk, timeout);
261 }
262 
263 static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval,
264 				int __user *optlen)
265 {
266 	int rc = 0;
267 	struct tls_context *ctx = tls_get_ctx(sk);
268 	struct tls_crypto_info *crypto_info;
269 	int len;
270 
271 	if (get_user(len, optlen))
272 		return -EFAULT;
273 
274 	if (!optval || (len < sizeof(*crypto_info))) {
275 		rc = -EINVAL;
276 		goto out;
277 	}
278 
279 	if (!ctx) {
280 		rc = -EBUSY;
281 		goto out;
282 	}
283 
284 	/* get user crypto info */
285 	crypto_info = &ctx->crypto_send;
286 
287 	if (!TLS_CRYPTO_INFO_READY(crypto_info)) {
288 		rc = -EBUSY;
289 		goto out;
290 	}
291 
292 	if (len == sizeof(*crypto_info)) {
293 		if (copy_to_user(optval, crypto_info, sizeof(*crypto_info)))
294 			rc = -EFAULT;
295 		goto out;
296 	}
297 
298 	switch (crypto_info->cipher_type) {
299 	case TLS_CIPHER_AES_GCM_128: {
300 		struct tls12_crypto_info_aes_gcm_128 *
301 		  crypto_info_aes_gcm_128 =
302 		  container_of(crypto_info,
303 			       struct tls12_crypto_info_aes_gcm_128,
304 			       info);
305 
306 		if (len != sizeof(*crypto_info_aes_gcm_128)) {
307 			rc = -EINVAL;
308 			goto out;
309 		}
310 		lock_sock(sk);
311 		memcpy(crypto_info_aes_gcm_128->iv, ctx->iv,
312 		       TLS_CIPHER_AES_GCM_128_IV_SIZE);
313 		release_sock(sk);
314 		if (copy_to_user(optval,
315 				 crypto_info_aes_gcm_128,
316 				 sizeof(*crypto_info_aes_gcm_128)))
317 			rc = -EFAULT;
318 		break;
319 	}
320 	default:
321 		rc = -EINVAL;
322 	}
323 
324 out:
325 	return rc;
326 }
327 
328 static int do_tls_getsockopt(struct sock *sk, int optname,
329 			     char __user *optval, int __user *optlen)
330 {
331 	int rc = 0;
332 
333 	switch (optname) {
334 	case TLS_TX:
335 		rc = do_tls_getsockopt_tx(sk, optval, optlen);
336 		break;
337 	default:
338 		rc = -ENOPROTOOPT;
339 		break;
340 	}
341 	return rc;
342 }
343 
344 static int tls_getsockopt(struct sock *sk, int level, int optname,
345 			  char __user *optval, int __user *optlen)
346 {
347 	struct tls_context *ctx = tls_get_ctx(sk);
348 
349 	if (level != SOL_TLS)
350 		return ctx->getsockopt(sk, level, optname, optval, optlen);
351 
352 	return do_tls_getsockopt(sk, optname, optval, optlen);
353 }
354 
355 static int do_tls_setsockopt_tx(struct sock *sk, char __user *optval,
356 				unsigned int optlen)
357 {
358 	struct tls_crypto_info *crypto_info;
359 	struct tls_context *ctx = tls_get_ctx(sk);
360 	int rc = 0;
361 	int tx_conf;
362 
363 	if (!optval || (optlen < sizeof(*crypto_info))) {
364 		rc = -EINVAL;
365 		goto out;
366 	}
367 
368 	crypto_info = &ctx->crypto_send;
369 	/* Currently we don't support set crypto info more than one time */
370 	if (TLS_CRYPTO_INFO_READY(crypto_info)) {
371 		rc = -EBUSY;
372 		goto out;
373 	}
374 
375 	rc = copy_from_user(crypto_info, optval, sizeof(*crypto_info));
376 	if (rc) {
377 		rc = -EFAULT;
378 		goto out;
379 	}
380 
381 	/* check version */
382 	if (crypto_info->version != TLS_1_2_VERSION) {
383 		rc = -ENOTSUPP;
384 		goto err_crypto_info;
385 	}
386 
387 	switch (crypto_info->cipher_type) {
388 	case TLS_CIPHER_AES_GCM_128: {
389 		if (optlen != sizeof(struct tls12_crypto_info_aes_gcm_128)) {
390 			rc = -EINVAL;
391 			goto err_crypto_info;
392 		}
393 		rc = copy_from_user(crypto_info + 1, optval + sizeof(*crypto_info),
394 				    optlen - sizeof(*crypto_info));
395 		if (rc) {
396 			rc = -EFAULT;
397 			goto err_crypto_info;
398 		}
399 		break;
400 	}
401 	default:
402 		rc = -EINVAL;
403 		goto err_crypto_info;
404 	}
405 
406 	/* currently SW is default, we will have ethtool in future */
407 	rc = tls_set_sw_offload(sk, ctx);
408 	tx_conf = TLS_SW_TX;
409 	if (rc)
410 		goto err_crypto_info;
411 
412 	ctx->tx_conf = tx_conf;
413 	update_sk_prot(sk, ctx);
414 	ctx->sk_write_space = sk->sk_write_space;
415 	sk->sk_write_space = tls_write_space;
416 	goto out;
417 
418 err_crypto_info:
419 	memset(crypto_info, 0, sizeof(*crypto_info));
420 out:
421 	return rc;
422 }
423 
424 static int do_tls_setsockopt(struct sock *sk, int optname,
425 			     char __user *optval, unsigned int optlen)
426 {
427 	int rc = 0;
428 
429 	switch (optname) {
430 	case TLS_TX:
431 		lock_sock(sk);
432 		rc = do_tls_setsockopt_tx(sk, optval, optlen);
433 		release_sock(sk);
434 		break;
435 	default:
436 		rc = -ENOPROTOOPT;
437 		break;
438 	}
439 	return rc;
440 }
441 
442 static int tls_setsockopt(struct sock *sk, int level, int optname,
443 			  char __user *optval, unsigned int optlen)
444 {
445 	struct tls_context *ctx = tls_get_ctx(sk);
446 
447 	if (level != SOL_TLS)
448 		return ctx->setsockopt(sk, level, optname, optval, optlen);
449 
450 	return do_tls_setsockopt(sk, optname, optval, optlen);
451 }
452 
453 static int tls_init(struct sock *sk)
454 {
455 	struct inet_connection_sock *icsk = inet_csk(sk);
456 	struct tls_context *ctx;
457 	int rc = 0;
458 
459 	/* The TLS ulp is currently supported only for TCP sockets
460 	 * in ESTABLISHED state.
461 	 * Supporting sockets in LISTEN state will require us
462 	 * to modify the accept implementation to clone rather then
463 	 * share the ulp context.
464 	 */
465 	if (sk->sk_state != TCP_ESTABLISHED)
466 		return -ENOTSUPP;
467 
468 	/* allocate tls context */
469 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
470 	if (!ctx) {
471 		rc = -ENOMEM;
472 		goto out;
473 	}
474 	icsk->icsk_ulp_data = ctx;
475 	ctx->setsockopt = sk->sk_prot->setsockopt;
476 	ctx->getsockopt = sk->sk_prot->getsockopt;
477 	ctx->sk_proto_close = sk->sk_prot->close;
478 
479 	ctx->tx_conf = TLS_BASE_TX;
480 	update_sk_prot(sk, ctx);
481 out:
482 	return rc;
483 }
484 
485 static struct tcp_ulp_ops tcp_tls_ulp_ops __read_mostly = {
486 	.name			= "tls",
487 	.uid			= TCP_ULP_TLS,
488 	.user_visible		= true,
489 	.owner			= THIS_MODULE,
490 	.init			= tls_init,
491 };
492 
493 static void build_protos(struct proto *prot, struct proto *base)
494 {
495 	prot[TLS_BASE_TX] = *base;
496 	prot[TLS_BASE_TX].setsockopt	= tls_setsockopt;
497 	prot[TLS_BASE_TX].getsockopt	= tls_getsockopt;
498 	prot[TLS_BASE_TX].close		= tls_sk_proto_close;
499 
500 	prot[TLS_SW_TX] = prot[TLS_BASE_TX];
501 	prot[TLS_SW_TX].sendmsg		= tls_sw_sendmsg;
502 	prot[TLS_SW_TX].sendpage	= tls_sw_sendpage;
503 }
504 
505 static int __init tls_register(void)
506 {
507 	build_protos(tls_prots, &tcp_prot);
508 
509 	tcp_register_ulp(&tcp_tls_ulp_ops);
510 
511 	return 0;
512 }
513 
514 static void __exit tls_unregister(void)
515 {
516 	tcp_unregister_ulp(&tcp_tls_ulp_ops);
517 }
518 
519 module_init(tls_register);
520 module_exit(tls_unregister);
521