xref: /linux/include/net/tls.h (revision c0b2826aa02a0747c3016457b9c1917ba14d0655)
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 #ifndef _TLS_OFFLOAD_H
35 #define _TLS_OFFLOAD_H
36 
37 #include <linux/types.h>
38 #include <asm/byteorder.h>
39 #include <linux/crypto.h>
40 #include <linux/socket.h>
41 #include <linux/tcp.h>
42 #include <linux/skmsg.h>
43 
44 #include <net/tcp.h>
45 #include <net/strparser.h>
46 #include <crypto/aead.h>
47 #include <uapi/linux/tls.h>
48 
49 
50 /* Maximum data size carried in a TLS record */
51 #define TLS_MAX_PAYLOAD_SIZE		((size_t)1 << 14)
52 
53 #define TLS_HEADER_SIZE			5
54 #define TLS_NONCE_OFFSET		TLS_HEADER_SIZE
55 
56 #define TLS_CRYPTO_INFO_READY(info)	((info)->cipher_type)
57 
58 #define TLS_RECORD_TYPE_DATA		0x17
59 
60 #define TLS_AAD_SPACE_SIZE		13
61 #define TLS_DEVICE_NAME_MAX		32
62 
63 /*
64  * This structure defines the routines for Inline TLS driver.
65  * The following routines are optional and filled with a
66  * null pointer if not defined.
67  *
68  * @name: Its the name of registered Inline tls device
69  * @dev_list: Inline tls device list
70  * int (*feature)(struct tls_device *device);
71  *     Called to return Inline TLS driver capability
72  *
73  * int (*hash)(struct tls_device *device, struct sock *sk);
74  *     This function sets Inline driver for listen and program
75  *     device specific functioanlity as required
76  *
77  * void (*unhash)(struct tls_device *device, struct sock *sk);
78  *     This function cleans listen state set by Inline TLS driver
79  */
80 struct tls_device {
81 	char name[TLS_DEVICE_NAME_MAX];
82 	struct list_head dev_list;
83 	int  (*feature)(struct tls_device *device);
84 	int  (*hash)(struct tls_device *device, struct sock *sk);
85 	void (*unhash)(struct tls_device *device, struct sock *sk);
86 };
87 
88 enum {
89 	TLS_BASE,
90 	TLS_SW,
91 #ifdef CONFIG_TLS_DEVICE
92 	TLS_HW,
93 #endif
94 	TLS_HW_RECORD,
95 	TLS_NUM_CONFIG,
96 };
97 
98 /* TLS records are maintained in 'struct tls_rec'. It stores the memory pages
99  * allocated or mapped for each TLS record. After encryption, the records are
100  * stores in a linked list.
101  */
102 struct tls_rec {
103 	struct list_head list;
104 	int tx_ready;
105 	int tx_flags;
106 	int inplace_crypto;
107 
108 	struct sk_msg msg_plaintext;
109 	struct sk_msg msg_encrypted;
110 
111 	/* AAD | msg_plaintext.sg.data | sg_tag */
112 	struct scatterlist sg_aead_in[2];
113 	/* AAD | msg_encrypted.sg.data (data contains overhead for hdr & iv & tag) */
114 	struct scatterlist sg_aead_out[2];
115 
116 	char aad_space[TLS_AAD_SPACE_SIZE];
117 	struct aead_request aead_req;
118 	u8 aead_req_ctx[];
119 };
120 
121 struct tx_work {
122 	struct delayed_work work;
123 	struct sock *sk;
124 };
125 
126 struct tls_sw_context_tx {
127 	struct crypto_aead *aead_send;
128 	struct crypto_wait async_wait;
129 	struct tx_work tx_work;
130 	struct tls_rec *open_rec;
131 	struct list_head tx_list;
132 	atomic_t encrypt_pending;
133 	int async_notify;
134 
135 #define BIT_TX_SCHEDULED	0
136 	unsigned long tx_bitmask;
137 };
138 
139 struct tls_sw_context_rx {
140 	struct crypto_aead *aead_recv;
141 	struct crypto_wait async_wait;
142 
143 	struct strparser strp;
144 	void (*saved_data_ready)(struct sock *sk);
145 
146 	struct sk_buff *recv_pkt;
147 	u8 control;
148 	bool decrypted;
149 	atomic_t decrypt_pending;
150 	bool async_notify;
151 };
152 
153 struct tls_record_info {
154 	struct list_head list;
155 	u32 end_seq;
156 	int len;
157 	int num_frags;
158 	skb_frag_t frags[MAX_SKB_FRAGS];
159 };
160 
161 struct tls_offload_context_tx {
162 	struct crypto_aead *aead_send;
163 	spinlock_t lock;	/* protects records list */
164 	struct list_head records_list;
165 	struct tls_record_info *open_record;
166 	struct tls_record_info *retransmit_hint;
167 	u64 hint_record_sn;
168 	u64 unacked_record_sn;
169 
170 	struct scatterlist sg_tx_data[MAX_SKB_FRAGS];
171 	void (*sk_destruct)(struct sock *sk);
172 	u8 driver_state[];
173 	/* The TLS layer reserves room for driver specific state
174 	 * Currently the belief is that there is not enough
175 	 * driver specific state to justify another layer of indirection
176 	 */
177 #define TLS_DRIVER_STATE_SIZE (max_t(size_t, 8, sizeof(void *)))
178 };
179 
180 #define TLS_OFFLOAD_CONTEXT_SIZE_TX                                            \
181 	(ALIGN(sizeof(struct tls_offload_context_tx), sizeof(void *)) +        \
182 	 TLS_DRIVER_STATE_SIZE)
183 
184 enum {
185 	TLS_PENDING_CLOSED_RECORD
186 };
187 
188 struct cipher_context {
189 	u16 prepend_size;
190 	u16 tag_size;
191 	u16 overhead_size;
192 	u16 iv_size;
193 	char *iv;
194 	u16 rec_seq_size;
195 	char *rec_seq;
196 };
197 
198 union tls_crypto_context {
199 	struct tls_crypto_info info;
200 	struct tls12_crypto_info_aes_gcm_128 aes_gcm_128;
201 };
202 
203 struct tls_context {
204 	union tls_crypto_context crypto_send;
205 	union tls_crypto_context crypto_recv;
206 
207 	struct list_head list;
208 	struct net_device *netdev;
209 	refcount_t refcount;
210 
211 	void *priv_ctx_tx;
212 	void *priv_ctx_rx;
213 
214 	u8 tx_conf:3;
215 	u8 rx_conf:3;
216 
217 	struct cipher_context tx;
218 	struct cipher_context rx;
219 
220 	struct scatterlist *partially_sent_record;
221 	u16 partially_sent_offset;
222 
223 	unsigned long flags;
224 	bool in_tcp_sendpages;
225 	bool pending_open_record_frags;
226 
227 	int (*push_pending_record)(struct sock *sk, int flags);
228 
229 	void (*sk_write_space)(struct sock *sk);
230 	void (*sk_destruct)(struct sock *sk);
231 	void (*sk_proto_close)(struct sock *sk, long timeout);
232 
233 	int  (*setsockopt)(struct sock *sk, int level,
234 			   int optname, char __user *optval,
235 			   unsigned int optlen);
236 	int  (*getsockopt)(struct sock *sk, int level,
237 			   int optname, char __user *optval,
238 			   int __user *optlen);
239 	int  (*hash)(struct sock *sk);
240 	void (*unhash)(struct sock *sk);
241 };
242 
243 struct tls_offload_context_rx {
244 	/* sw must be the first member of tls_offload_context_rx */
245 	struct tls_sw_context_rx sw;
246 	atomic64_t resync_req;
247 	u8 driver_state[];
248 	/* The TLS layer reserves room for driver specific state
249 	 * Currently the belief is that there is not enough
250 	 * driver specific state to justify another layer of indirection
251 	 */
252 };
253 
254 #define TLS_OFFLOAD_CONTEXT_SIZE_RX					\
255 	(ALIGN(sizeof(struct tls_offload_context_rx), sizeof(void *)) + \
256 	 TLS_DRIVER_STATE_SIZE)
257 
258 int wait_on_pending_writer(struct sock *sk, long *timeo);
259 int tls_sk_query(struct sock *sk, int optname, char __user *optval,
260 		int __user *optlen);
261 int tls_sk_attach(struct sock *sk, int optname, char __user *optval,
262 		  unsigned int optlen);
263 
264 int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx);
265 int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
266 int tls_sw_sendpage(struct sock *sk, struct page *page,
267 		    int offset, size_t size, int flags);
268 void tls_sw_close(struct sock *sk, long timeout);
269 void tls_sw_free_resources_tx(struct sock *sk);
270 void tls_sw_free_resources_rx(struct sock *sk);
271 void tls_sw_release_resources_rx(struct sock *sk);
272 int tls_sw_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
273 		   int nonblock, int flags, int *addr_len);
274 bool tls_sw_stream_read(const struct sock *sk);
275 ssize_t tls_sw_splice_read(struct socket *sock, loff_t *ppos,
276 			   struct pipe_inode_info *pipe,
277 			   size_t len, unsigned int flags);
278 
279 int tls_set_device_offload(struct sock *sk, struct tls_context *ctx);
280 int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
281 int tls_device_sendpage(struct sock *sk, struct page *page,
282 			int offset, size_t size, int flags);
283 void tls_device_sk_destruct(struct sock *sk);
284 void tls_device_init(void);
285 void tls_device_cleanup(void);
286 int tls_tx_records(struct sock *sk, int flags);
287 
288 struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
289 				       u32 seq, u64 *p_record_sn);
290 
291 static inline bool tls_record_is_start_marker(struct tls_record_info *rec)
292 {
293 	return rec->len == 0;
294 }
295 
296 static inline u32 tls_record_start_seq(struct tls_record_info *rec)
297 {
298 	return rec->end_seq - rec->len;
299 }
300 
301 void tls_sk_destruct(struct sock *sk, struct tls_context *ctx);
302 int tls_push_sg(struct sock *sk, struct tls_context *ctx,
303 		struct scatterlist *sg, u16 first_offset,
304 		int flags);
305 int tls_push_partial_record(struct sock *sk, struct tls_context *ctx,
306 			    int flags);
307 
308 int tls_push_pending_closed_record(struct sock *sk, struct tls_context *ctx,
309 				   int flags, long *timeo);
310 
311 static inline bool tls_is_pending_closed_record(struct tls_context *ctx)
312 {
313 	return test_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
314 }
315 
316 static inline int tls_complete_pending_work(struct sock *sk,
317 					    struct tls_context *ctx,
318 					    int flags, long *timeo)
319 {
320 	int rc = 0;
321 
322 	if (unlikely(sk->sk_write_pending))
323 		rc = wait_on_pending_writer(sk, timeo);
324 
325 	if (!rc && tls_is_pending_closed_record(ctx))
326 		rc = tls_push_pending_closed_record(sk, ctx, flags, timeo);
327 
328 	return rc;
329 }
330 
331 static inline bool tls_is_partially_sent_record(struct tls_context *ctx)
332 {
333 	return !!ctx->partially_sent_record;
334 }
335 
336 static inline bool tls_is_pending_open_record(struct tls_context *tls_ctx)
337 {
338 	return tls_ctx->pending_open_record_frags;
339 }
340 
341 static inline bool is_tx_ready(struct tls_sw_context_tx *ctx)
342 {
343 	struct tls_rec *rec;
344 
345 	rec = list_first_entry(&ctx->tx_list, struct tls_rec, list);
346 	if (!rec)
347 		return false;
348 
349 	return READ_ONCE(rec->tx_ready);
350 }
351 
352 struct sk_buff *
353 tls_validate_xmit_skb(struct sock *sk, struct net_device *dev,
354 		      struct sk_buff *skb);
355 
356 static inline bool tls_is_sk_tx_device_offloaded(struct sock *sk)
357 {
358 #ifdef CONFIG_SOCK_VALIDATE_XMIT
359 	return sk_fullsock(sk) &
360 	       (smp_load_acquire(&sk->sk_validate_xmit_skb) ==
361 	       &tls_validate_xmit_skb);
362 #else
363 	return false;
364 #endif
365 }
366 
367 static inline void tls_err_abort(struct sock *sk, int err)
368 {
369 	sk->sk_err = err;
370 	sk->sk_error_report(sk);
371 }
372 
373 static inline bool tls_bigint_increment(unsigned char *seq, int len)
374 {
375 	int i;
376 
377 	for (i = len - 1; i >= 0; i--) {
378 		++seq[i];
379 		if (seq[i] != 0)
380 			break;
381 	}
382 
383 	return (i == -1);
384 }
385 
386 static inline void tls_advance_record_sn(struct sock *sk,
387 					 struct cipher_context *ctx)
388 {
389 	if (tls_bigint_increment(ctx->rec_seq, ctx->rec_seq_size))
390 		tls_err_abort(sk, EBADMSG);
391 	tls_bigint_increment(ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
392 			     ctx->iv_size);
393 }
394 
395 static inline void tls_fill_prepend(struct tls_context *ctx,
396 			     char *buf,
397 			     size_t plaintext_len,
398 			     unsigned char record_type)
399 {
400 	size_t pkt_len, iv_size = ctx->tx.iv_size;
401 
402 	pkt_len = plaintext_len + iv_size + ctx->tx.tag_size;
403 
404 	/* we cover nonce explicit here as well, so buf should be of
405 	 * size KTLS_DTLS_HEADER_SIZE + KTLS_DTLS_NONCE_EXPLICIT_SIZE
406 	 */
407 	buf[0] = record_type;
408 	buf[1] = TLS_VERSION_MINOR(ctx->crypto_send.info.version);
409 	buf[2] = TLS_VERSION_MAJOR(ctx->crypto_send.info.version);
410 	/* we can use IV for nonce explicit according to spec */
411 	buf[3] = pkt_len >> 8;
412 	buf[4] = pkt_len & 0xFF;
413 	memcpy(buf + TLS_NONCE_OFFSET,
414 	       ctx->tx.iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv_size);
415 }
416 
417 static inline void tls_make_aad(char *buf,
418 				size_t size,
419 				char *record_sequence,
420 				int record_sequence_size,
421 				unsigned char record_type)
422 {
423 	memcpy(buf, record_sequence, record_sequence_size);
424 
425 	buf[8] = record_type;
426 	buf[9] = TLS_1_2_VERSION_MAJOR;
427 	buf[10] = TLS_1_2_VERSION_MINOR;
428 	buf[11] = size >> 8;
429 	buf[12] = size & 0xFF;
430 }
431 
432 static inline struct tls_context *tls_get_ctx(const struct sock *sk)
433 {
434 	struct inet_connection_sock *icsk = inet_csk(sk);
435 
436 	return icsk->icsk_ulp_data;
437 }
438 
439 static inline struct tls_sw_context_rx *tls_sw_ctx_rx(
440 		const struct tls_context *tls_ctx)
441 {
442 	return (struct tls_sw_context_rx *)tls_ctx->priv_ctx_rx;
443 }
444 
445 static inline struct tls_sw_context_tx *tls_sw_ctx_tx(
446 		const struct tls_context *tls_ctx)
447 {
448 	return (struct tls_sw_context_tx *)tls_ctx->priv_ctx_tx;
449 }
450 
451 static inline struct tls_offload_context_tx *
452 tls_offload_ctx_tx(const struct tls_context *tls_ctx)
453 {
454 	return (struct tls_offload_context_tx *)tls_ctx->priv_ctx_tx;
455 }
456 
457 static inline struct tls_offload_context_rx *
458 tls_offload_ctx_rx(const struct tls_context *tls_ctx)
459 {
460 	return (struct tls_offload_context_rx *)tls_ctx->priv_ctx_rx;
461 }
462 
463 /* The TLS context is valid until sk_destruct is called */
464 static inline void tls_offload_rx_resync_request(struct sock *sk, __be32 seq)
465 {
466 	struct tls_context *tls_ctx = tls_get_ctx(sk);
467 	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
468 
469 	atomic64_set(&rx_ctx->resync_req, ((((uint64_t)seq) << 32) | 1));
470 }
471 
472 
473 int tls_proccess_cmsg(struct sock *sk, struct msghdr *msg,
474 		      unsigned char *record_type);
475 void tls_register_device(struct tls_device *device);
476 void tls_unregister_device(struct tls_device *device);
477 int tls_device_decrypted(struct sock *sk, struct sk_buff *skb);
478 int decrypt_skb(struct sock *sk, struct sk_buff *skb,
479 		struct scatterlist *sgout);
480 
481 struct sk_buff *tls_validate_xmit_skb(struct sock *sk,
482 				      struct net_device *dev,
483 				      struct sk_buff *skb);
484 
485 int tls_sw_fallback_init(struct sock *sk,
486 			 struct tls_offload_context_tx *offload_ctx,
487 			 struct tls_crypto_info *crypto_info);
488 
489 int tls_set_device_offload_rx(struct sock *sk, struct tls_context *ctx);
490 
491 void tls_device_offload_cleanup_rx(struct sock *sk);
492 void handle_device_resync(struct sock *sk, u32 seq, u64 rcd_sn);
493 
494 #endif /* _TLS_OFFLOAD_H */
495