tls.h

  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
 52struct tls_rec;
 53
 54/* Maximum data size carried in a TLS record */
 55#define TLS_MAX_PAYLOAD_SIZE		((size_t)1 << 14)
 56/* Minimum record size limit as per RFC8449 */
 57#define TLS_MIN_RECORD_SIZE_LIM		((size_t)1 << 6)
 58
 59#define TLS_HEADER_SIZE			5
 60#define TLS_NONCE_OFFSET		TLS_HEADER_SIZE
 61
 62#define TLS_CRYPTO_INFO_READY(info)	((info)->cipher_type)
 63
 64#define TLS_HANDSHAKE_KEYUPDATE		24	/* rfc8446 B.3: Key update */
 65
 66#define TLS_AAD_SPACE_SIZE		13
 67
 68#define TLS_MAX_IV_SIZE			16
 69#define TLS_MAX_SALT_SIZE		4
 70#define TLS_TAG_SIZE			16
 71#define TLS_MAX_REC_SEQ_SIZE		8
 72#define TLS_MAX_AAD_SIZE		TLS_AAD_SPACE_SIZE
 73
 74/* For CCM mode, the full 16-bytes of IV is made of '4' fields of given sizes.
 75 *
 76 * IV[16] = b0[1] || implicit nonce[4] || explicit nonce[8] || length[3]
 77 *
 78 * The field 'length' is encoded in field 'b0' as '(length width - 1)'.
 79 * Hence b0 contains (3 - 1) = 2.
 80 */
 81#define TLS_AES_CCM_IV_B0_BYTE		2
 82#define TLS_SM4_CCM_IV_B0_BYTE		2
 83
 84enum {
 85	TLS_BASE,
 86	TLS_SW,
 87	TLS_HW,
 88	TLS_HW_RECORD,
 89	TLS_NUM_CONFIG,
 90};
 91
 92struct tx_work {
 93	struct delayed_work work;
 94	struct sock *sk;
 95};
 96
 97struct tls_sw_context_tx {
 98	struct crypto_aead *aead_send;
 99	struct crypto_wait async_wait;
100	struct tx_work tx_work;
101	struct tls_rec *open_rec;
102	struct list_head tx_list;
103	atomic_t encrypt_pending;
104	u8 async_capable:1;
105
106#define BIT_TX_SCHEDULED	0
107#define BIT_TX_CLOSING		1
108	unsigned long tx_bitmask;
109};
110
111struct tls_strparser {
112	struct sock *sk;
113
114	u32 mark : 8;
115	u32 stopped : 1;
116	u32 copy_mode : 1;
117	u32 mixed_decrypted : 1;
118
119	bool msg_ready;
120
121	struct strp_msg stm;
122
123	struct sk_buff *anchor;
124	struct work_struct work;
125};
126
127struct tls_sw_context_rx {
128	struct crypto_aead *aead_recv;
129	struct crypto_wait async_wait;
130	struct sk_buff_head rx_list;	/* list of decrypted 'data' records */
131	void (*saved_data_ready)(struct sock *sk);
132
133	u8 reader_present;
134	u8 async_capable:1;
135	u8 zc_capable:1;
136	u8 reader_contended:1;
137	bool key_update_pending;
138
139	struct tls_strparser strp;
140
141	atomic_t decrypt_pending;
142	struct sk_buff_head async_hold;
143	struct wait_queue_head wq;
144};
145
146struct tls_record_info {
147	struct list_head list;
148	u32 end_seq;
149	int len;
150	int num_frags;
151	skb_frag_t frags[MAX_SKB_FRAGS];
152};
153
154#define TLS_DRIVER_STATE_SIZE_TX	16
155struct tls_offload_context_tx {
156	struct crypto_aead *aead_send;
157	spinlock_t lock;	/* protects records list */
158	struct list_head records_list;
159	struct tls_record_info *open_record;
160	struct tls_record_info *retransmit_hint;
161	u64 hint_record_sn;
162	u64 unacked_record_sn;
163
164	struct scatterlist sg_tx_data[MAX_SKB_FRAGS];
165	void (*sk_destruct)(struct sock *sk);
166	struct work_struct destruct_work;
167	struct tls_context *ctx;
168	/* The TLS layer reserves room for driver specific state
169	 * Currently the belief is that there is not enough
170	 * driver specific state to justify another layer of indirection
171	 */
172	u8 driver_state[TLS_DRIVER_STATE_SIZE_TX] __aligned(8);
173};
174
175enum tls_context_flags {
176	/* tls_device_down was called after the netdev went down, device state
177	 * was released, and kTLS works in software, even though rx_conf is
178	 * still TLS_HW (needed for transition).
179	 */
180	TLS_RX_DEV_DEGRADED = 0,
181	/* Unlike RX where resync is driven entirely by the core in TX only
182	 * the driver knows when things went out of sync, so we need the flag
183	 * to be atomic.
184	 */
185	TLS_TX_SYNC_SCHED = 1,
186	/* tls_dev_del was called for the RX side, device state was released,
187	 * but tls_ctx->netdev might still be kept, because TX-side driver
188	 * resources might not be released yet. Used to prevent the second
189	 * tls_dev_del call in tls_device_down if it happens simultaneously.
190	 */
191	TLS_RX_DEV_CLOSED = 2,
192};
193
194struct cipher_context {
195	char iv[TLS_MAX_IV_SIZE + TLS_MAX_SALT_SIZE];
196	char rec_seq[TLS_MAX_REC_SEQ_SIZE];
197};
198
199union tls_crypto_context {
200	struct tls_crypto_info info;
201	union {
202		struct tls12_crypto_info_aes_gcm_128 aes_gcm_128;
203		struct tls12_crypto_info_aes_gcm_256 aes_gcm_256;
204		struct tls12_crypto_info_chacha20_poly1305 chacha20_poly1305;
205		struct tls12_crypto_info_sm4_gcm sm4_gcm;
206		struct tls12_crypto_info_sm4_ccm sm4_ccm;
207	};
208};
209
210struct tls_prot_info {
211	u16 version;
212	u16 cipher_type;
213	u16 prepend_size;
214	u16 tag_size;
215	u16 overhead_size;
216	u16 iv_size;
217	u16 salt_size;
218	u16 rec_seq_size;
219	u16 aad_size;
220	u16 tail_size;
221};
222
223struct tls_context {
224	/* read-only cache line */
225	struct tls_prot_info prot_info;
226
227	u8 tx_conf:3;
228	u8 rx_conf:3;
229	u8 zerocopy_sendfile:1;
230	u8 rx_no_pad:1;
231	u16 tx_max_payload_len;
232
233	int (*push_pending_record)(struct sock *sk, int flags);
234	void (*sk_write_space)(struct sock *sk);
235
236	void *priv_ctx_tx;
237	void *priv_ctx_rx;
238
239	struct net_device __rcu *netdev;
240
241	/* rw cache line */
242	struct cipher_context tx;
243	struct cipher_context rx;
244
245	struct scatterlist *partially_sent_record;
246	u16 partially_sent_offset;
247
248	bool splicing_pages;
249	bool pending_open_record_frags;
250
251	struct mutex tx_lock; /* protects partially_sent_* fields and
252			       * per-type TX fields
253			       */
254	unsigned long flags;
255
256	/* cache cold stuff */
257	struct proto *sk_proto;
258	struct sock *sk;
259
260	void (*sk_destruct)(struct sock *sk);
261
262	union tls_crypto_context crypto_send;
263	union tls_crypto_context crypto_recv;
264
265	struct list_head list;
266	refcount_t refcount;
267	struct rcu_head rcu;
268};
269
270enum tls_offload_ctx_dir {
271	TLS_OFFLOAD_CTX_DIR_RX,
272	TLS_OFFLOAD_CTX_DIR_TX,
273};
274
275struct tlsdev_ops {
276	int (*tls_dev_add)(struct net_device *netdev, struct sock *sk,
277			   enum tls_offload_ctx_dir direction,
278			   struct tls_crypto_info *crypto_info,
279			   u32 start_offload_tcp_sn);
280	void (*tls_dev_del)(struct net_device *netdev,
281			    struct tls_context *ctx,
282			    enum tls_offload_ctx_dir direction);
283	int (*tls_dev_resync)(struct net_device *netdev,
284			      struct sock *sk, u32 seq, u8 *rcd_sn,
285			      enum tls_offload_ctx_dir direction);
286};
287
288enum tls_offload_sync_type {
289	TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ = 0,
290	TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT = 1,
291	TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ_ASYNC = 2,
292};
293
294#define TLS_DEVICE_RESYNC_NH_START_IVAL		2
295#define TLS_DEVICE_RESYNC_NH_MAX_IVAL		128
296
297#define TLS_DEVICE_RESYNC_ASYNC_LOGMAX		13
298struct tls_offload_resync_async {
299	atomic64_t req;
300	u16 loglen;
301	u16 rcd_delta;
302	u32 log[TLS_DEVICE_RESYNC_ASYNC_LOGMAX];
303};
304
305#define TLS_DRIVER_STATE_SIZE_RX	8
306struct tls_offload_context_rx {
307	/* sw must be the first member of tls_offload_context_rx */
308	struct tls_sw_context_rx sw;
309	enum tls_offload_sync_type resync_type;
310	/* this member is set regardless of resync_type, to avoid branches */
311	u8 resync_nh_reset:1;
312	/* CORE_NEXT_HINT-only member, but use the hole here */
313	u8 resync_nh_do_now:1;
314	union {
315		/* TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ */
316		struct {
317			atomic64_t resync_req;
318		};
319		/* TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT */
320		struct {
321			u32 decrypted_failed;
322			u32 decrypted_tgt;
323		} resync_nh;
324		/* TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ_ASYNC */
325		struct {
326			struct tls_offload_resync_async *resync_async;
327		};
328	};
329	/* The TLS layer reserves room for driver specific state
330	 * Currently the belief is that there is not enough
331	 * driver specific state to justify another layer of indirection
332	 */
333	u8 driver_state[TLS_DRIVER_STATE_SIZE_RX] __aligned(8);
334};
335
336struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
337				       u32 seq, u64 *p_record_sn);
338
339static inline bool tls_record_is_start_marker(struct tls_record_info *rec)
340{
341	return rec->len == 0;
342}
343
344static inline u32 tls_record_start_seq(struct tls_record_info *rec)
345{
346	return rec->end_seq - rec->len;
347}
348
349struct sk_buff *
350tls_validate_xmit_skb(struct sock *sk, struct net_device *dev,
351		      struct sk_buff *skb);
352struct sk_buff *
353tls_validate_xmit_skb_sw(struct sock *sk, struct net_device *dev,
354			 struct sk_buff *skb);
355
356static inline bool tls_is_skb_tx_device_offloaded(const struct sk_buff *skb)
357{
358#ifdef CONFIG_TLS_DEVICE
359	struct sock *sk = skb->sk;
360
361	return sk && sk_fullsock(sk) &&
362	       (smp_load_acquire(&sk->sk_validate_xmit_skb) ==
363	       &tls_validate_xmit_skb);
364#else
365	return false;
366#endif
367}
368
369static inline struct tls_context *tls_get_ctx(const struct sock *sk)
370{
371	const struct inet_connection_sock *icsk = inet_csk(sk);
372
373	/* Use RCU on icsk_ulp_data only for sock diag code,
374	 * TLS data path doesn't need rcu_dereference().
375	 */
376	return (__force void *)icsk->icsk_ulp_data;
377}
378
379static inline struct tls_sw_context_rx *tls_sw_ctx_rx(
380		const struct tls_context *tls_ctx)
381{
382	return (struct tls_sw_context_rx *)tls_ctx->priv_ctx_rx;
383}
384
385static inline struct tls_sw_context_tx *tls_sw_ctx_tx(
386		const struct tls_context *tls_ctx)
387{
388	return (struct tls_sw_context_tx *)tls_ctx->priv_ctx_tx;
389}
390
391static inline struct tls_offload_context_tx *
392tls_offload_ctx_tx(const struct tls_context *tls_ctx)
393{
394	return (struct tls_offload_context_tx *)tls_ctx->priv_ctx_tx;
395}
396
397static inline bool tls_sw_has_ctx_tx(const struct sock *sk)
398{
399	struct tls_context *ctx;
400
401	if (!sk_is_inet(sk) || !inet_test_bit(IS_ICSK, sk))
402		return false;
403
404	ctx = tls_get_ctx(sk);
405	if (!ctx)
406		return false;
407	return !!tls_sw_ctx_tx(ctx);
408}
409
410static inline bool tls_sw_has_ctx_rx(const struct sock *sk)
411{
412	struct tls_context *ctx;
413
414	if (!sk_is_inet(sk) || !inet_test_bit(IS_ICSK, sk))
415		return false;
416
417	ctx = tls_get_ctx(sk);
418	if (!ctx)
419		return false;
420	return !!tls_sw_ctx_rx(ctx);
421}
422
423static inline struct tls_offload_context_rx *
424tls_offload_ctx_rx(const struct tls_context *tls_ctx)
425{
426	return (struct tls_offload_context_rx *)tls_ctx->priv_ctx_rx;
427}
428
429static inline void *__tls_driver_ctx(struct tls_context *tls_ctx,
430				     enum tls_offload_ctx_dir direction)
431{
432	if (direction == TLS_OFFLOAD_CTX_DIR_TX)
433		return tls_offload_ctx_tx(tls_ctx)->driver_state;
434	else
435		return tls_offload_ctx_rx(tls_ctx)->driver_state;
436}
437
438static inline void *
439tls_driver_ctx(const struct sock *sk, enum tls_offload_ctx_dir direction)
440{
441	return __tls_driver_ctx(tls_get_ctx(sk), direction);
442}
443
444#define RESYNC_REQ BIT(0)
445#define RESYNC_REQ_ASYNC BIT(1)
446/* The TLS context is valid until sk_destruct is called */
447static inline void tls_offload_rx_resync_request(struct sock *sk, __be32 seq)
448{
449	struct tls_context *tls_ctx = tls_get_ctx(sk);
450	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
451
452	atomic64_set(&rx_ctx->resync_req, ((u64)ntohl(seq) << 32) | RESYNC_REQ);
453}
454
455/* Log all TLS record header TCP sequences in [seq, seq+len] */
456static inline void
457tls_offload_rx_resync_async_request_start(struct tls_offload_resync_async *resync_async,
458					  __be32 seq, u16 len)
459{
460	atomic64_set(&resync_async->req, ((u64)ntohl(seq) << 32) |
461		     ((u64)len << 16) | RESYNC_REQ | RESYNC_REQ_ASYNC);
462	resync_async->loglen = 0;
463	resync_async->rcd_delta = 0;
464}
465
466static inline void
467tls_offload_rx_resync_async_request_end(struct tls_offload_resync_async *resync_async,
468					__be32 seq)
469{
470	atomic64_set(&resync_async->req, ((u64)ntohl(seq) << 32) | RESYNC_REQ);
471}
472
473static inline void
474tls_offload_rx_resync_async_request_cancel(struct tls_offload_resync_async *resync_async)
475{
476	atomic64_set(&resync_async->req, 0);
477}
478
479static inline void
480tls_offload_rx_resync_set_type(struct sock *sk, enum tls_offload_sync_type type)
481{
482	struct tls_context *tls_ctx = tls_get_ctx(sk);
483
484	tls_offload_ctx_rx(tls_ctx)->resync_type = type;
485}
486
487/* Driver's seq tracking has to be disabled until resync succeeded */
488static inline bool tls_offload_tx_resync_pending(struct sock *sk)
489{
490	struct tls_context *tls_ctx = tls_get_ctx(sk);
491	bool ret;
492
493	ret = test_bit(TLS_TX_SYNC_SCHED, &tls_ctx->flags);
494	smp_mb__after_atomic();
495	return ret;
496}
497
498struct sk_buff *tls_encrypt_skb(struct sk_buff *skb);
499
500#ifdef CONFIG_TLS_DEVICE
501void tls_device_sk_destruct(struct sock *sk);
502void tls_offload_tx_resync_request(struct sock *sk, u32 got_seq, u32 exp_seq);
503
504static inline bool tls_is_sk_rx_device_offloaded(struct sock *sk)
505{
506	if (!sk_fullsock(sk) ||
507	    smp_load_acquire(&sk->sk_destruct) != tls_device_sk_destruct)
508		return false;
509	return tls_get_ctx(sk)->rx_conf == TLS_HW;
510}
511#endif
512#endif /* _TLS_OFFLOAD_H */