xref: /openbmc/linux/include/net/tls.h (revision 7f8256ae)
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_ALERT		0x15
73 #define TLS_RECORD_TYPE_HANDSHAKE	0x16
74 #define TLS_RECORD_TYPE_DATA		0x17
75 
76 #define TLS_AAD_SPACE_SIZE		13
77 
78 #define MAX_IV_SIZE			16
79 #define TLS_TAG_SIZE			16
80 #define TLS_MAX_REC_SEQ_SIZE		8
81 #define TLS_MAX_AAD_SIZE		TLS_AAD_SPACE_SIZE
82 
83 /* For CCM mode, the full 16-bytes of IV is made of '4' fields of given sizes.
84  *
85  * IV[16] = b0[1] || implicit nonce[4] || explicit nonce[8] || length[3]
86  *
87  * The field 'length' is encoded in field 'b0' as '(length width - 1)'.
88  * Hence b0 contains (3 - 1) = 2.
89  */
90 #define TLS_AES_CCM_IV_B0_BYTE		2
91 #define TLS_SM4_CCM_IV_B0_BYTE		2
92 
93 enum {
94 	TLS_BASE,
95 	TLS_SW,
96 	TLS_HW,
97 	TLS_HW_RECORD,
98 	TLS_NUM_CONFIG,
99 };
100 
101 struct tx_work {
102 	struct delayed_work work;
103 	struct sock *sk;
104 };
105 
106 struct tls_sw_context_tx {
107 	struct crypto_aead *aead_send;
108 	struct crypto_wait async_wait;
109 	struct tx_work tx_work;
110 	struct tls_rec *open_rec;
111 	struct list_head tx_list;
112 	atomic_t encrypt_pending;
113 	/* protect crypto_wait with encrypt_pending */
114 	spinlock_t encrypt_compl_lock;
115 	int async_notify;
116 	u8 async_capable:1;
117 
118 #define BIT_TX_SCHEDULED	0
119 #define BIT_TX_CLOSING		1
120 	unsigned long tx_bitmask;
121 };
122 
123 struct tls_strparser {
124 	struct sock *sk;
125 
126 	u32 mark : 8;
127 	u32 stopped : 1;
128 	u32 copy_mode : 1;
129 	u32 msg_ready : 1;
130 
131 	struct strp_msg stm;
132 
133 	struct sk_buff *anchor;
134 	struct work_struct work;
135 };
136 
137 struct tls_sw_context_rx {
138 	struct crypto_aead *aead_recv;
139 	struct crypto_wait async_wait;
140 	struct sk_buff_head rx_list;	/* list of decrypted 'data' records */
141 	void (*saved_data_ready)(struct sock *sk);
142 
143 	u8 reader_present;
144 	u8 async_capable:1;
145 	u8 zc_capable:1;
146 	u8 reader_contended:1;
147 
148 	struct tls_strparser strp;
149 
150 	atomic_t decrypt_pending;
151 	/* protect crypto_wait with decrypt_pending*/
152 	spinlock_t decrypt_compl_lock;
153 	struct sk_buff_head async_hold;
154 	struct wait_queue_head wq;
155 };
156 
157 struct tls_record_info {
158 	struct list_head list;
159 	u32 end_seq;
160 	int len;
161 	int num_frags;
162 	skb_frag_t frags[MAX_SKB_FRAGS];
163 };
164 
165 struct tls_offload_context_tx {
166 	struct crypto_aead *aead_send;
167 	spinlock_t lock;	/* protects records list */
168 	struct list_head records_list;
169 	struct tls_record_info *open_record;
170 	struct tls_record_info *retransmit_hint;
171 	u64 hint_record_sn;
172 	u64 unacked_record_sn;
173 
174 	struct scatterlist sg_tx_data[MAX_SKB_FRAGS];
175 	void (*sk_destruct)(struct sock *sk);
176 	struct work_struct destruct_work;
177 	struct tls_context *ctx;
178 	u8 driver_state[] __aligned(8);
179 	/* The TLS layer reserves room for driver specific state
180 	 * Currently the belief is that there is not enough
181 	 * driver specific state to justify another layer of indirection
182 	 */
183 #define TLS_DRIVER_STATE_SIZE_TX	16
184 };
185 
186 #define TLS_OFFLOAD_CONTEXT_SIZE_TX                                            \
187 	(sizeof(struct tls_offload_context_tx) + TLS_DRIVER_STATE_SIZE_TX)
188 
189 enum tls_context_flags {
190 	/* tls_device_down was called after the netdev went down, device state
191 	 * was released, and kTLS works in software, even though rx_conf is
192 	 * still TLS_HW (needed for transition).
193 	 */
194 	TLS_RX_DEV_DEGRADED = 0,
195 	/* Unlike RX where resync is driven entirely by the core in TX only
196 	 * the driver knows when things went out of sync, so we need the flag
197 	 * to be atomic.
198 	 */
199 	TLS_TX_SYNC_SCHED = 1,
200 	/* tls_dev_del was called for the RX side, device state was released,
201 	 * but tls_ctx->netdev might still be kept, because TX-side driver
202 	 * resources might not be released yet. Used to prevent the second
203 	 * tls_dev_del call in tls_device_down if it happens simultaneously.
204 	 */
205 	TLS_RX_DEV_CLOSED = 2,
206 };
207 
208 struct cipher_context {
209 	char *iv;
210 	char *rec_seq;
211 };
212 
213 union tls_crypto_context {
214 	struct tls_crypto_info info;
215 	union {
216 		struct tls12_crypto_info_aes_gcm_128 aes_gcm_128;
217 		struct tls12_crypto_info_aes_gcm_256 aes_gcm_256;
218 		struct tls12_crypto_info_chacha20_poly1305 chacha20_poly1305;
219 		struct tls12_crypto_info_sm4_gcm sm4_gcm;
220 		struct tls12_crypto_info_sm4_ccm sm4_ccm;
221 	};
222 };
223 
224 struct tls_prot_info {
225 	u16 version;
226 	u16 cipher_type;
227 	u16 prepend_size;
228 	u16 tag_size;
229 	u16 overhead_size;
230 	u16 iv_size;
231 	u16 salt_size;
232 	u16 rec_seq_size;
233 	u16 aad_size;
234 	u16 tail_size;
235 };
236 
237 struct tls_context {
238 	/* read-only cache line */
239 	struct tls_prot_info prot_info;
240 
241 	u8 tx_conf:3;
242 	u8 rx_conf:3;
243 	u8 zerocopy_sendfile:1;
244 	u8 rx_no_pad:1;
245 
246 	int (*push_pending_record)(struct sock *sk, int flags);
247 	void (*sk_write_space)(struct sock *sk);
248 
249 	void *priv_ctx_tx;
250 	void *priv_ctx_rx;
251 
252 	struct net_device __rcu *netdev;
253 
254 	/* rw cache line */
255 	struct cipher_context tx;
256 	struct cipher_context rx;
257 
258 	struct scatterlist *partially_sent_record;
259 	u16 partially_sent_offset;
260 
261 	bool in_tcp_sendpages;
262 	bool pending_open_record_frags;
263 
264 	struct mutex tx_lock; /* protects partially_sent_* fields and
265 			       * per-type TX fields
266 			       */
267 	unsigned long flags;
268 
269 	/* cache cold stuff */
270 	struct proto *sk_proto;
271 	struct sock *sk;
272 
273 	void (*sk_destruct)(struct sock *sk);
274 
275 	union tls_crypto_context crypto_send;
276 	union tls_crypto_context crypto_recv;
277 
278 	struct list_head list;
279 	refcount_t refcount;
280 	struct rcu_head rcu;
281 };
282 
283 enum tls_offload_ctx_dir {
284 	TLS_OFFLOAD_CTX_DIR_RX,
285 	TLS_OFFLOAD_CTX_DIR_TX,
286 };
287 
288 struct tlsdev_ops {
289 	int (*tls_dev_add)(struct net_device *netdev, struct sock *sk,
290 			   enum tls_offload_ctx_dir direction,
291 			   struct tls_crypto_info *crypto_info,
292 			   u32 start_offload_tcp_sn);
293 	void (*tls_dev_del)(struct net_device *netdev,
294 			    struct tls_context *ctx,
295 			    enum tls_offload_ctx_dir direction);
296 	int (*tls_dev_resync)(struct net_device *netdev,
297 			      struct sock *sk, u32 seq, u8 *rcd_sn,
298 			      enum tls_offload_ctx_dir direction);
299 };
300 
301 enum tls_offload_sync_type {
302 	TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ = 0,
303 	TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT = 1,
304 	TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ_ASYNC = 2,
305 };
306 
307 #define TLS_DEVICE_RESYNC_NH_START_IVAL		2
308 #define TLS_DEVICE_RESYNC_NH_MAX_IVAL		128
309 
310 #define TLS_DEVICE_RESYNC_ASYNC_LOGMAX		13
311 struct tls_offload_resync_async {
312 	atomic64_t req;
313 	u16 loglen;
314 	u16 rcd_delta;
315 	u32 log[TLS_DEVICE_RESYNC_ASYNC_LOGMAX];
316 };
317 
318 struct tls_offload_context_rx {
319 	/* sw must be the first member of tls_offload_context_rx */
320 	struct tls_sw_context_rx sw;
321 	enum tls_offload_sync_type resync_type;
322 	/* this member is set regardless of resync_type, to avoid branches */
323 	u8 resync_nh_reset:1;
324 	/* CORE_NEXT_HINT-only member, but use the hole here */
325 	u8 resync_nh_do_now:1;
326 	union {
327 		/* TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ */
328 		struct {
329 			atomic64_t resync_req;
330 		};
331 		/* TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT */
332 		struct {
333 			u32 decrypted_failed;
334 			u32 decrypted_tgt;
335 		} resync_nh;
336 		/* TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ_ASYNC */
337 		struct {
338 			struct tls_offload_resync_async *resync_async;
339 		};
340 	};
341 	u8 driver_state[] __aligned(8);
342 	/* The TLS layer reserves room for driver specific state
343 	 * Currently the belief is that there is not enough
344 	 * driver specific state to justify another layer of indirection
345 	 */
346 #define TLS_DRIVER_STATE_SIZE_RX	8
347 };
348 
349 #define TLS_OFFLOAD_CONTEXT_SIZE_RX					\
350 	(sizeof(struct tls_offload_context_rx) + TLS_DRIVER_STATE_SIZE_RX)
351 
352 struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
353 				       u32 seq, u64 *p_record_sn);
354 
355 static inline bool tls_record_is_start_marker(struct tls_record_info *rec)
356 {
357 	return rec->len == 0;
358 }
359 
360 static inline u32 tls_record_start_seq(struct tls_record_info *rec)
361 {
362 	return rec->end_seq - rec->len;
363 }
364 
365 struct sk_buff *
366 tls_validate_xmit_skb(struct sock *sk, struct net_device *dev,
367 		      struct sk_buff *skb);
368 struct sk_buff *
369 tls_validate_xmit_skb_sw(struct sock *sk, struct net_device *dev,
370 			 struct sk_buff *skb);
371 
372 static inline bool tls_is_sk_tx_device_offloaded(struct sock *sk)
373 {
374 #ifdef CONFIG_SOCK_VALIDATE_XMIT
375 	return sk_fullsock(sk) &&
376 	       (smp_load_acquire(&sk->sk_validate_xmit_skb) ==
377 	       &tls_validate_xmit_skb);
378 #else
379 	return false;
380 #endif
381 }
382 
383 static inline struct tls_context *tls_get_ctx(const struct sock *sk)
384 {
385 	struct inet_connection_sock *icsk = inet_csk(sk);
386 
387 	/* Use RCU on icsk_ulp_data only for sock diag code,
388 	 * TLS data path doesn't need rcu_dereference().
389 	 */
390 	return (__force void *)icsk->icsk_ulp_data;
391 }
392 
393 static inline struct tls_sw_context_rx *tls_sw_ctx_rx(
394 		const struct tls_context *tls_ctx)
395 {
396 	return (struct tls_sw_context_rx *)tls_ctx->priv_ctx_rx;
397 }
398 
399 static inline struct tls_sw_context_tx *tls_sw_ctx_tx(
400 		const struct tls_context *tls_ctx)
401 {
402 	return (struct tls_sw_context_tx *)tls_ctx->priv_ctx_tx;
403 }
404 
405 static inline struct tls_offload_context_tx *
406 tls_offload_ctx_tx(const struct tls_context *tls_ctx)
407 {
408 	return (struct tls_offload_context_tx *)tls_ctx->priv_ctx_tx;
409 }
410 
411 static inline bool tls_sw_has_ctx_tx(const struct sock *sk)
412 {
413 	struct tls_context *ctx = tls_get_ctx(sk);
414 
415 	if (!ctx)
416 		return false;
417 	return !!tls_sw_ctx_tx(ctx);
418 }
419 
420 static inline bool tls_sw_has_ctx_rx(const struct sock *sk)
421 {
422 	struct tls_context *ctx = tls_get_ctx(sk);
423 
424 	if (!ctx)
425 		return false;
426 	return !!tls_sw_ctx_rx(ctx);
427 }
428 
429 static inline struct tls_offload_context_rx *
430 tls_offload_ctx_rx(const struct tls_context *tls_ctx)
431 {
432 	return (struct tls_offload_context_rx *)tls_ctx->priv_ctx_rx;
433 }
434 
435 static inline void *__tls_driver_ctx(struct tls_context *tls_ctx,
436 				     enum tls_offload_ctx_dir direction)
437 {
438 	if (direction == TLS_OFFLOAD_CTX_DIR_TX)
439 		return tls_offload_ctx_tx(tls_ctx)->driver_state;
440 	else
441 		return tls_offload_ctx_rx(tls_ctx)->driver_state;
442 }
443 
444 static inline void *
445 tls_driver_ctx(const struct sock *sk, enum tls_offload_ctx_dir direction)
446 {
447 	return __tls_driver_ctx(tls_get_ctx(sk), direction);
448 }
449 
450 #define RESYNC_REQ BIT(0)
451 #define RESYNC_REQ_ASYNC BIT(1)
452 /* The TLS context is valid until sk_destruct is called */
453 static inline void tls_offload_rx_resync_request(struct sock *sk, __be32 seq)
454 {
455 	struct tls_context *tls_ctx = tls_get_ctx(sk);
456 	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
457 
458 	atomic64_set(&rx_ctx->resync_req, ((u64)ntohl(seq) << 32) | RESYNC_REQ);
459 }
460 
461 /* Log all TLS record header TCP sequences in [seq, seq+len] */
462 static inline void
463 tls_offload_rx_resync_async_request_start(struct sock *sk, __be32 seq, u16 len)
464 {
465 	struct tls_context *tls_ctx = tls_get_ctx(sk);
466 	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
467 
468 	atomic64_set(&rx_ctx->resync_async->req, ((u64)ntohl(seq) << 32) |
469 		     ((u64)len << 16) | RESYNC_REQ | RESYNC_REQ_ASYNC);
470 	rx_ctx->resync_async->loglen = 0;
471 	rx_ctx->resync_async->rcd_delta = 0;
472 }
473 
474 static inline void
475 tls_offload_rx_resync_async_request_end(struct sock *sk, __be32 seq)
476 {
477 	struct tls_context *tls_ctx = tls_get_ctx(sk);
478 	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
479 
480 	atomic64_set(&rx_ctx->resync_async->req,
481 		     ((u64)ntohl(seq) << 32) | RESYNC_REQ);
482 }
483 
484 static inline void
485 tls_offload_rx_resync_set_type(struct sock *sk, enum tls_offload_sync_type type)
486 {
487 	struct tls_context *tls_ctx = tls_get_ctx(sk);
488 
489 	tls_offload_ctx_rx(tls_ctx)->resync_type = type;
490 }
491 
492 /* Driver's seq tracking has to be disabled until resync succeeded */
493 static inline bool tls_offload_tx_resync_pending(struct sock *sk)
494 {
495 	struct tls_context *tls_ctx = tls_get_ctx(sk);
496 	bool ret;
497 
498 	ret = test_bit(TLS_TX_SYNC_SCHED, &tls_ctx->flags);
499 	smp_mb__after_atomic();
500 	return ret;
501 }
502 
503 struct sk_buff *tls_encrypt_skb(struct sk_buff *skb);
504 
505 #ifdef CONFIG_TLS_DEVICE
506 void tls_device_sk_destruct(struct sock *sk);
507 void tls_offload_tx_resync_request(struct sock *sk, u32 got_seq, u32 exp_seq);
508 
509 static inline bool tls_is_sk_rx_device_offloaded(struct sock *sk)
510 {
511 	if (!sk_fullsock(sk) ||
512 	    smp_load_acquire(&sk->sk_destruct) != tls_device_sk_destruct)
513 		return false;
514 	return tls_get_ctx(sk)->rx_conf == TLS_HW;
515 }
516 #endif
517 #endif /* _TLS_OFFLOAD_H */
518