xref: /linux/include/net/tls.h (revision cc8c418b4fc09ed58ddd27b8e90ec797e9ca1e67)
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/mutex.h>
43 #include <linux/netdevice.h>
44 #include <linux/rcupdate.h>
45 
46 #include <net/net_namespace.h>
47 #include <net/tcp.h>
48 #include <net/strparser.h>
49 #include <crypto/aead.h>
50 #include <uapi/linux/tls.h>
51 
52 struct tls_rec;
53 
54 struct tls_cipher_size_desc {
55 	unsigned int iv;
56 	unsigned int key;
57 	unsigned int salt;
58 	unsigned int tag;
59 	unsigned int rec_seq;
60 };
61 
62 extern const struct tls_cipher_size_desc tls_cipher_size_desc[];
63 
64 /* Maximum data size carried in a TLS record */
65 #define TLS_MAX_PAYLOAD_SIZE		((size_t)1 << 14)
66 
67 #define TLS_HEADER_SIZE			5
68 #define TLS_NONCE_OFFSET		TLS_HEADER_SIZE
69 
70 #define TLS_CRYPTO_INFO_READY(info)	((info)->cipher_type)
71 
72 #define TLS_RECORD_TYPE_DATA		0x17
73 
74 #define TLS_AAD_SPACE_SIZE		13
75 
76 #define MAX_IV_SIZE			16
77 #define TLS_TAG_SIZE			16
78 #define TLS_MAX_REC_SEQ_SIZE		8
79 #define TLS_MAX_AAD_SIZE		TLS_AAD_SPACE_SIZE
80 
81 /* For CCM mode, the full 16-bytes of IV is made of '4' fields of given sizes.
82  *
83  * IV[16] = b0[1] || implicit nonce[4] || explicit nonce[8] || length[3]
84  *
85  * The field 'length' is encoded in field 'b0' as '(length width - 1)'.
86  * Hence b0 contains (3 - 1) = 2.
87  */
88 #define TLS_AES_CCM_IV_B0_BYTE		2
89 #define TLS_SM4_CCM_IV_B0_BYTE		2
90 
91 enum {
92 	TLS_BASE,
93 	TLS_SW,
94 	TLS_HW,
95 	TLS_HW_RECORD,
96 	TLS_NUM_CONFIG,
97 };
98 
99 struct tx_work {
100 	struct delayed_work work;
101 	struct sock *sk;
102 };
103 
104 struct tls_sw_context_tx {
105 	struct crypto_aead *aead_send;
106 	struct crypto_wait async_wait;
107 	struct tx_work tx_work;
108 	struct tls_rec *open_rec;
109 	struct list_head tx_list;
110 	atomic_t encrypt_pending;
111 	/* protect crypto_wait with encrypt_pending */
112 	spinlock_t encrypt_compl_lock;
113 	int async_notify;
114 	u8 async_capable:1;
115 
116 #define BIT_TX_SCHEDULED	0
117 #define BIT_TX_CLOSING		1
118 	unsigned long tx_bitmask;
119 };
120 
121 struct tls_strparser {
122 	struct sock *sk;
123 
124 	u32 mark : 8;
125 	u32 stopped : 1;
126 	u32 copy_mode : 1;
127 	u32 msg_ready : 1;
128 
129 	struct strp_msg stm;
130 
131 	struct sk_buff *anchor;
132 	struct work_struct work;
133 };
134 
135 struct tls_sw_context_rx {
136 	struct crypto_aead *aead_recv;
137 	struct crypto_wait async_wait;
138 	struct sk_buff_head rx_list;	/* list of decrypted 'data' records */
139 	void (*saved_data_ready)(struct sock *sk);
140 
141 	u8 reader_present;
142 	u8 async_capable:1;
143 	u8 zc_capable:1;
144 	u8 reader_contended:1;
145 
146 	struct tls_strparser strp;
147 
148 	atomic_t decrypt_pending;
149 	/* protect crypto_wait with decrypt_pending*/
150 	spinlock_t decrypt_compl_lock;
151 	struct sk_buff_head async_hold;
152 	struct wait_queue_head wq;
153 };
154 
155 struct tls_record_info {
156 	struct list_head list;
157 	u32 end_seq;
158 	int len;
159 	int num_frags;
160 	skb_frag_t frags[MAX_SKB_FRAGS];
161 };
162 
163 struct tls_offload_context_tx {
164 	struct crypto_aead *aead_send;
165 	spinlock_t lock;	/* protects records list */
166 	struct list_head records_list;
167 	struct tls_record_info *open_record;
168 	struct tls_record_info *retransmit_hint;
169 	u64 hint_record_sn;
170 	u64 unacked_record_sn;
171 
172 	struct scatterlist sg_tx_data[MAX_SKB_FRAGS];
173 	void (*sk_destruct)(struct sock *sk);
174 	struct work_struct destruct_work;
175 	struct tls_context *ctx;
176 	u8 driver_state[] __aligned(8);
177 	/* The TLS layer reserves room for driver specific state
178 	 * Currently the belief is that there is not enough
179 	 * driver specific state to justify another layer of indirection
180 	 */
181 #define TLS_DRIVER_STATE_SIZE_TX	16
182 };
183 
184 #define TLS_OFFLOAD_CONTEXT_SIZE_TX                                            \
185 	(sizeof(struct tls_offload_context_tx) + TLS_DRIVER_STATE_SIZE_TX)
186 
187 enum tls_context_flags {
188 	/* tls_device_down was called after the netdev went down, device state
189 	 * was released, and kTLS works in software, even though rx_conf is
190 	 * still TLS_HW (needed for transition).
191 	 */
192 	TLS_RX_DEV_DEGRADED = 0,
193 	/* Unlike RX where resync is driven entirely by the core in TX only
194 	 * the driver knows when things went out of sync, so we need the flag
195 	 * to be atomic.
196 	 */
197 	TLS_TX_SYNC_SCHED = 1,
198 	/* tls_dev_del was called for the RX side, device state was released,
199 	 * but tls_ctx->netdev might still be kept, because TX-side driver
200 	 * resources might not be released yet. Used to prevent the second
201 	 * tls_dev_del call in tls_device_down if it happens simultaneously.
202 	 */
203 	TLS_RX_DEV_CLOSED = 2,
204 };
205 
206 struct cipher_context {
207 	char *iv;
208 	char *rec_seq;
209 };
210 
211 union tls_crypto_context {
212 	struct tls_crypto_info info;
213 	union {
214 		struct tls12_crypto_info_aes_gcm_128 aes_gcm_128;
215 		struct tls12_crypto_info_aes_gcm_256 aes_gcm_256;
216 		struct tls12_crypto_info_chacha20_poly1305 chacha20_poly1305;
217 		struct tls12_crypto_info_sm4_gcm sm4_gcm;
218 		struct tls12_crypto_info_sm4_ccm sm4_ccm;
219 	};
220 };
221 
222 struct tls_prot_info {
223 	u16 version;
224 	u16 cipher_type;
225 	u16 prepend_size;
226 	u16 tag_size;
227 	u16 overhead_size;
228 	u16 iv_size;
229 	u16 salt_size;
230 	u16 rec_seq_size;
231 	u16 aad_size;
232 	u16 tail_size;
233 };
234 
235 struct tls_context {
236 	/* read-only cache line */
237 	struct tls_prot_info prot_info;
238 
239 	u8 tx_conf:3;
240 	u8 rx_conf:3;
241 	u8 zerocopy_sendfile:1;
242 	u8 rx_no_pad:1;
243 
244 	int (*push_pending_record)(struct sock *sk, int flags);
245 	void (*sk_write_space)(struct sock *sk);
246 
247 	void *priv_ctx_tx;
248 	void *priv_ctx_rx;
249 
250 	struct net_device __rcu *netdev;
251 
252 	/* rw cache line */
253 	struct cipher_context tx;
254 	struct cipher_context rx;
255 
256 	struct scatterlist *partially_sent_record;
257 	u16 partially_sent_offset;
258 
259 	bool in_tcp_sendpages;
260 	bool pending_open_record_frags;
261 
262 	struct mutex tx_lock; /* protects partially_sent_* fields and
263 			       * per-type TX fields
264 			       */
265 	unsigned long flags;
266 
267 	/* cache cold stuff */
268 	struct proto *sk_proto;
269 	struct sock *sk;
270 
271 	void (*sk_destruct)(struct sock *sk);
272 
273 	union tls_crypto_context crypto_send;
274 	union tls_crypto_context crypto_recv;
275 
276 	struct list_head list;
277 	refcount_t refcount;
278 	struct rcu_head rcu;
279 };
280 
281 enum tls_offload_ctx_dir {
282 	TLS_OFFLOAD_CTX_DIR_RX,
283 	TLS_OFFLOAD_CTX_DIR_TX,
284 };
285 
286 struct tlsdev_ops {
287 	int (*tls_dev_add)(struct net_device *netdev, struct sock *sk,
288 			   enum tls_offload_ctx_dir direction,
289 			   struct tls_crypto_info *crypto_info,
290 			   u32 start_offload_tcp_sn);
291 	void (*tls_dev_del)(struct net_device *netdev,
292 			    struct tls_context *ctx,
293 			    enum tls_offload_ctx_dir direction);
294 	int (*tls_dev_resync)(struct net_device *netdev,
295 			      struct sock *sk, u32 seq, u8 *rcd_sn,
296 			      enum tls_offload_ctx_dir direction);
297 };
298 
299 enum tls_offload_sync_type {
300 	TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ = 0,
301 	TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT = 1,
302 	TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ_ASYNC = 2,
303 };
304 
305 #define TLS_DEVICE_RESYNC_NH_START_IVAL		2
306 #define TLS_DEVICE_RESYNC_NH_MAX_IVAL		128
307 
308 #define TLS_DEVICE_RESYNC_ASYNC_LOGMAX		13
309 struct tls_offload_resync_async {
310 	atomic64_t req;
311 	u16 loglen;
312 	u16 rcd_delta;
313 	u32 log[TLS_DEVICE_RESYNC_ASYNC_LOGMAX];
314 };
315 
316 struct tls_offload_context_rx {
317 	/* sw must be the first member of tls_offload_context_rx */
318 	struct tls_sw_context_rx sw;
319 	enum tls_offload_sync_type resync_type;
320 	/* this member is set regardless of resync_type, to avoid branches */
321 	u8 resync_nh_reset:1;
322 	/* CORE_NEXT_HINT-only member, but use the hole here */
323 	u8 resync_nh_do_now:1;
324 	union {
325 		/* TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ */
326 		struct {
327 			atomic64_t resync_req;
328 		};
329 		/* TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT */
330 		struct {
331 			u32 decrypted_failed;
332 			u32 decrypted_tgt;
333 		} resync_nh;
334 		/* TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ_ASYNC */
335 		struct {
336 			struct tls_offload_resync_async *resync_async;
337 		};
338 	};
339 	u8 driver_state[] __aligned(8);
340 	/* The TLS layer reserves room for driver specific state
341 	 * Currently the belief is that there is not enough
342 	 * driver specific state to justify another layer of indirection
343 	 */
344 #define TLS_DRIVER_STATE_SIZE_RX	8
345 };
346 
347 #define TLS_OFFLOAD_CONTEXT_SIZE_RX					\
348 	(sizeof(struct tls_offload_context_rx) + TLS_DRIVER_STATE_SIZE_RX)
349 
350 struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
351 				       u32 seq, u64 *p_record_sn);
352 
353 static inline bool tls_record_is_start_marker(struct tls_record_info *rec)
354 {
355 	return rec->len == 0;
356 }
357 
358 static inline u32 tls_record_start_seq(struct tls_record_info *rec)
359 {
360 	return rec->end_seq - rec->len;
361 }
362 
363 struct sk_buff *
364 tls_validate_xmit_skb(struct sock *sk, struct net_device *dev,
365 		      struct sk_buff *skb);
366 struct sk_buff *
367 tls_validate_xmit_skb_sw(struct sock *sk, struct net_device *dev,
368 			 struct sk_buff *skb);
369 
370 static inline bool tls_is_sk_tx_device_offloaded(struct sock *sk)
371 {
372 #ifdef CONFIG_SOCK_VALIDATE_XMIT
373 	return sk_fullsock(sk) &&
374 	       (smp_load_acquire(&sk->sk_validate_xmit_skb) ==
375 	       &tls_validate_xmit_skb);
376 #else
377 	return false;
378 #endif
379 }
380 
381 static inline struct tls_context *tls_get_ctx(const struct sock *sk)
382 {
383 	struct inet_connection_sock *icsk = inet_csk(sk);
384 
385 	/* Use RCU on icsk_ulp_data only for sock diag code,
386 	 * TLS data path doesn't need rcu_dereference().
387 	 */
388 	return (__force void *)icsk->icsk_ulp_data;
389 }
390 
391 static inline struct tls_sw_context_rx *tls_sw_ctx_rx(
392 		const struct tls_context *tls_ctx)
393 {
394 	return (struct tls_sw_context_rx *)tls_ctx->priv_ctx_rx;
395 }
396 
397 static inline struct tls_sw_context_tx *tls_sw_ctx_tx(
398 		const struct tls_context *tls_ctx)
399 {
400 	return (struct tls_sw_context_tx *)tls_ctx->priv_ctx_tx;
401 }
402 
403 static inline struct tls_offload_context_tx *
404 tls_offload_ctx_tx(const struct tls_context *tls_ctx)
405 {
406 	return (struct tls_offload_context_tx *)tls_ctx->priv_ctx_tx;
407 }
408 
409 static inline bool tls_sw_has_ctx_tx(const struct sock *sk)
410 {
411 	struct tls_context *ctx = tls_get_ctx(sk);
412 
413 	if (!ctx)
414 		return false;
415 	return !!tls_sw_ctx_tx(ctx);
416 }
417 
418 static inline bool tls_sw_has_ctx_rx(const struct sock *sk)
419 {
420 	struct tls_context *ctx = tls_get_ctx(sk);
421 
422 	if (!ctx)
423 		return false;
424 	return !!tls_sw_ctx_rx(ctx);
425 }
426 
427 static inline struct tls_offload_context_rx *
428 tls_offload_ctx_rx(const struct tls_context *tls_ctx)
429 {
430 	return (struct tls_offload_context_rx *)tls_ctx->priv_ctx_rx;
431 }
432 
433 static inline void *__tls_driver_ctx(struct tls_context *tls_ctx,
434 				     enum tls_offload_ctx_dir direction)
435 {
436 	if (direction == TLS_OFFLOAD_CTX_DIR_TX)
437 		return tls_offload_ctx_tx(tls_ctx)->driver_state;
438 	else
439 		return tls_offload_ctx_rx(tls_ctx)->driver_state;
440 }
441 
442 static inline void *
443 tls_driver_ctx(const struct sock *sk, enum tls_offload_ctx_dir direction)
444 {
445 	return __tls_driver_ctx(tls_get_ctx(sk), direction);
446 }
447 
448 #define RESYNC_REQ BIT(0)
449 #define RESYNC_REQ_ASYNC BIT(1)
450 /* The TLS context is valid until sk_destruct is called */
451 static inline void tls_offload_rx_resync_request(struct sock *sk, __be32 seq)
452 {
453 	struct tls_context *tls_ctx = tls_get_ctx(sk);
454 	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
455 
456 	atomic64_set(&rx_ctx->resync_req, ((u64)ntohl(seq) << 32) | RESYNC_REQ);
457 }
458 
459 /* Log all TLS record header TCP sequences in [seq, seq+len] */
460 static inline void
461 tls_offload_rx_resync_async_request_start(struct sock *sk, __be32 seq, u16 len)
462 {
463 	struct tls_context *tls_ctx = tls_get_ctx(sk);
464 	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
465 
466 	atomic64_set(&rx_ctx->resync_async->req, ((u64)ntohl(seq) << 32) |
467 		     ((u64)len << 16) | RESYNC_REQ | RESYNC_REQ_ASYNC);
468 	rx_ctx->resync_async->loglen = 0;
469 	rx_ctx->resync_async->rcd_delta = 0;
470 }
471 
472 static inline void
473 tls_offload_rx_resync_async_request_end(struct sock *sk, __be32 seq)
474 {
475 	struct tls_context *tls_ctx = tls_get_ctx(sk);
476 	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
477 
478 	atomic64_set(&rx_ctx->resync_async->req,
479 		     ((u64)ntohl(seq) << 32) | RESYNC_REQ);
480 }
481 
482 static inline void
483 tls_offload_rx_resync_set_type(struct sock *sk, enum tls_offload_sync_type type)
484 {
485 	struct tls_context *tls_ctx = tls_get_ctx(sk);
486 
487 	tls_offload_ctx_rx(tls_ctx)->resync_type = type;
488 }
489 
490 /* Driver's seq tracking has to be disabled until resync succeeded */
491 static inline bool tls_offload_tx_resync_pending(struct sock *sk)
492 {
493 	struct tls_context *tls_ctx = tls_get_ctx(sk);
494 	bool ret;
495 
496 	ret = test_bit(TLS_TX_SYNC_SCHED, &tls_ctx->flags);
497 	smp_mb__after_atomic();
498 	return ret;
499 }
500 
501 struct sk_buff *tls_encrypt_skb(struct sk_buff *skb);
502 
503 #ifdef CONFIG_TLS_DEVICE
504 void tls_device_sk_destruct(struct sock *sk);
505 void tls_offload_tx_resync_request(struct sock *sk, u32 got_seq, u32 exp_seq);
506 
507 static inline bool tls_is_sk_rx_device_offloaded(struct sock *sk)
508 {
509 	if (!sk_fullsock(sk) ||
510 	    smp_load_acquire(&sk->sk_destruct) != tls_device_sk_destruct)
511 		return false;
512 	return tls_get_ctx(sk)->rx_conf == TLS_HW;
513 }
514 #endif
515 #endif /* _TLS_OFFLOAD_H */
516