1 // SPDX-License-Identifier: GPL-2.0
2 #include <net/tcp.h>
3 #include <net/strparser.h>
4 #include <net/xfrm.h>
5 #include <net/esp.h>
6 #include <net/espintcp.h>
7 #include <linux/skmsg.h>
8 #include <net/inet_common.h>
9 #include <trace/events/sock.h>
10 #include <net/hotdata.h>
11
handle_nonesp(struct espintcp_ctx * ctx,struct sk_buff * skb,struct sock * sk)12 static void handle_nonesp(struct espintcp_ctx *ctx, struct sk_buff *skb,
13 struct sock *sk)
14 {
15 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf ||
16 !sk_rmem_schedule(sk, skb, skb->truesize)) {
17 XFRM_INC_STATS(sock_net(sk), LINUX_MIB_XFRMINERROR);
18 kfree_skb(skb);
19 return;
20 }
21
22 skb_set_owner_r(skb, sk);
23
24 memset(skb->cb, 0, sizeof(skb->cb));
25 skb_queue_tail(&ctx->ike_queue, skb);
26 ctx->saved_data_ready(sk);
27 }
28
handle_esp(struct sk_buff * skb,struct sock * sk)29 static void handle_esp(struct sk_buff *skb, struct sock *sk)
30 {
31 struct tcp_skb_cb *tcp_cb = (struct tcp_skb_cb *)skb->cb;
32
33 skb_reset_transport_header(skb);
34
35 /* restore IP CB, we need at least IP6CB->nhoff */
36 memmove(skb->cb, &tcp_cb->header, sizeof(tcp_cb->header));
37
38 rcu_read_lock();
39 skb->dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif);
40 local_bh_disable();
41 #if IS_ENABLED(CONFIG_IPV6)
42 if (sk->sk_family == AF_INET6)
43 xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP);
44 else
45 #endif
46 xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP);
47 local_bh_enable();
48 rcu_read_unlock();
49 }
50
espintcp_rcv(struct strparser * strp,struct sk_buff * skb)51 static void espintcp_rcv(struct strparser *strp, struct sk_buff *skb)
52 {
53 struct espintcp_ctx *ctx = container_of(strp, struct espintcp_ctx,
54 strp);
55 struct strp_msg *rxm = strp_msg(skb);
56 int len = rxm->full_len - 2;
57 u32 nonesp_marker;
58 int err;
59
60 /* keepalive packet? */
61 if (unlikely(len == 1)) {
62 u8 data;
63
64 err = skb_copy_bits(skb, rxm->offset + 2, &data, 1);
65 if (err < 0) {
66 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
67 kfree_skb(skb);
68 return;
69 }
70
71 if (data == 0xff) {
72 kfree_skb(skb);
73 return;
74 }
75 }
76
77 /* drop other short messages */
78 if (unlikely(len <= sizeof(nonesp_marker))) {
79 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
80 kfree_skb(skb);
81 return;
82 }
83
84 err = skb_copy_bits(skb, rxm->offset + 2, &nonesp_marker,
85 sizeof(nonesp_marker));
86 if (err < 0) {
87 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
88 kfree_skb(skb);
89 return;
90 }
91
92 /* remove header, leave non-ESP marker/SPI */
93 if (!pskb_pull(skb, rxm->offset + 2)) {
94 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR);
95 kfree_skb(skb);
96 return;
97 }
98
99 if (pskb_trim(skb, rxm->full_len - 2) != 0) {
100 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR);
101 kfree_skb(skb);
102 return;
103 }
104
105 if (nonesp_marker == 0)
106 handle_nonesp(ctx, skb, strp->sk);
107 else
108 handle_esp(skb, strp->sk);
109 }
110
espintcp_parse(struct strparser * strp,struct sk_buff * skb)111 static int espintcp_parse(struct strparser *strp, struct sk_buff *skb)
112 {
113 struct strp_msg *rxm = strp_msg(skb);
114 __be16 blen;
115 u16 len;
116 int err;
117
118 if (skb->len < rxm->offset + 2)
119 return 0;
120
121 err = skb_copy_bits(skb, rxm->offset, &blen, sizeof(blen));
122 if (err < 0)
123 return err;
124
125 len = be16_to_cpu(blen);
126 if (len < 2)
127 return -EINVAL;
128
129 return len;
130 }
131
espintcp_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags)132 static int espintcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
133 int flags)
134 {
135 struct espintcp_ctx *ctx = espintcp_getctx(sk);
136 struct sk_buff *skb;
137 int err = 0;
138 int copied;
139 int off = 0;
140
141 skb = __skb_recv_datagram(sk, &ctx->ike_queue, flags, &off, &err);
142 if (!skb) {
143 if (err == -EAGAIN && sk->sk_shutdown & RCV_SHUTDOWN)
144 return 0;
145 return err;
146 }
147
148 copied = len;
149 if (copied > skb->len)
150 copied = skb->len;
151 else if (copied < skb->len)
152 msg->msg_flags |= MSG_TRUNC;
153
154 err = skb_copy_datagram_msg(skb, 0, msg, copied);
155 if (unlikely(err)) {
156 kfree_skb(skb);
157 return err;
158 }
159
160 if (flags & MSG_TRUNC)
161 copied = skb->len;
162 kfree_skb(skb);
163 return copied;
164 }
165
espintcp_queue_out(struct sock * sk,struct sk_buff * skb)166 int espintcp_queue_out(struct sock *sk, struct sk_buff *skb)
167 {
168 struct espintcp_ctx *ctx = espintcp_getctx(sk);
169
170 if (skb_queue_len(&ctx->out_queue) >=
171 READ_ONCE(net_hotdata.max_backlog)) {
172 kfree_skb(skb);
173 return -ENOBUFS;
174 }
175
176 __skb_queue_tail(&ctx->out_queue, skb);
177
178 return 0;
179 }
180 EXPORT_SYMBOL_GPL(espintcp_queue_out);
181
182 /* espintcp length field is 2B and length includes the length field's size */
183 #define MAX_ESPINTCP_MSG (((1 << 16) - 1) - 2)
184
espintcp_sendskb_locked(struct sock * sk,struct espintcp_msg * emsg,int flags)185 static int espintcp_sendskb_locked(struct sock *sk, struct espintcp_msg *emsg,
186 int flags)
187 {
188 do {
189 int ret;
190
191 ret = skb_send_sock_locked(sk, emsg->skb,
192 emsg->offset, emsg->len);
193 if (ret < 0)
194 return ret;
195
196 emsg->len -= ret;
197 emsg->offset += ret;
198 } while (emsg->len > 0);
199
200 kfree_skb(emsg->skb);
201 memset(emsg, 0, sizeof(*emsg));
202
203 return 0;
204 }
205
espintcp_sendskmsg_locked(struct sock * sk,struct espintcp_msg * emsg,int flags)206 static int espintcp_sendskmsg_locked(struct sock *sk,
207 struct espintcp_msg *emsg, int flags)
208 {
209 struct msghdr msghdr = {
210 .msg_flags = flags | MSG_SPLICE_PAGES | MSG_MORE,
211 };
212 struct sk_msg *skmsg = &emsg->skmsg;
213 bool more = flags & MSG_MORE;
214 struct scatterlist *sg;
215 int ret;
216
217 do {
218 struct bio_vec bvec;
219
220 sg = &skmsg->sg.data[skmsg->sg.start];
221 if (sg_is_last(sg) && !more)
222 msghdr.msg_flags &= ~MSG_MORE;
223
224 bvec_set_page(&bvec, sg_page(sg), sg->length, sg->offset);
225 iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, sg->length);
226 ret = tcp_sendmsg_locked(sk, &msghdr, sg->length);
227 if (ret < 0)
228 return ret;
229
230 sk_msg_free_partial(sk, skmsg, ret);
231 } while (skmsg->sg.size);
232
233 memset(emsg, 0, sizeof(*emsg));
234
235 return 0;
236 }
237
espintcp_push_msgs(struct sock * sk,int flags)238 static int espintcp_push_msgs(struct sock *sk, int flags)
239 {
240 struct espintcp_ctx *ctx = espintcp_getctx(sk);
241 struct espintcp_msg *emsg = &ctx->partial;
242 int err;
243
244 if (!emsg->len)
245 return 0;
246
247 if (ctx->tx_running)
248 return -EAGAIN;
249 ctx->tx_running = 1;
250
251 if (emsg->skb)
252 err = espintcp_sendskb_locked(sk, emsg, flags);
253 else
254 err = espintcp_sendskmsg_locked(sk, emsg, flags);
255 if (err == -EAGAIN) {
256 ctx->tx_running = 0;
257 return flags & MSG_DONTWAIT ? -EAGAIN : 0;
258 }
259 if (!err)
260 memset(emsg, 0, sizeof(*emsg));
261
262 ctx->tx_running = 0;
263
264 return err;
265 }
266
espintcp_push_skb(struct sock * sk,struct sk_buff * skb)267 int espintcp_push_skb(struct sock *sk, struct sk_buff *skb)
268 {
269 struct espintcp_ctx *ctx = espintcp_getctx(sk);
270 struct espintcp_msg *emsg = &ctx->partial;
271 unsigned int len;
272 int offset;
273
274 if (sk->sk_state != TCP_ESTABLISHED) {
275 kfree_skb(skb);
276 return -ECONNRESET;
277 }
278
279 offset = skb_transport_offset(skb);
280 len = skb->len - offset;
281
282 espintcp_push_msgs(sk, 0);
283
284 if (emsg->len) {
285 kfree_skb(skb);
286 return -ENOBUFS;
287 }
288
289 skb_set_owner_w(skb, sk);
290
291 emsg->offset = offset;
292 emsg->len = len;
293 emsg->skb = skb;
294
295 espintcp_push_msgs(sk, 0);
296
297 return 0;
298 }
299 EXPORT_SYMBOL_GPL(espintcp_push_skb);
300
espintcp_sendmsg(struct sock * sk,struct msghdr * msg,size_t size)301 static int espintcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
302 {
303 long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
304 struct espintcp_ctx *ctx = espintcp_getctx(sk);
305 struct espintcp_msg *emsg = &ctx->partial;
306 struct iov_iter pfx_iter;
307 struct kvec pfx_iov = {};
308 size_t msglen = size + 2;
309 char buf[2] = {0};
310 int err, end;
311
312 if (msg->msg_flags & ~MSG_DONTWAIT)
313 return -EOPNOTSUPP;
314
315 if (size > MAX_ESPINTCP_MSG)
316 return -EMSGSIZE;
317
318 if (msg->msg_controllen)
319 return -EOPNOTSUPP;
320
321 lock_sock(sk);
322
323 err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT);
324 if (err < 0) {
325 if (err != -EAGAIN || !(msg->msg_flags & MSG_DONTWAIT))
326 err = -ENOBUFS;
327 goto unlock;
328 }
329 if (emsg->len) {
330 err = -ENOBUFS;
331 goto unlock;
332 }
333
334 sk_msg_init(&emsg->skmsg);
335 while (1) {
336 /* only -ENOMEM is possible since we don't coalesce */
337 err = sk_msg_alloc(sk, &emsg->skmsg, msglen, 0);
338 if (!err)
339 break;
340
341 err = sk_stream_wait_memory(sk, &timeo);
342 if (err)
343 goto fail;
344 }
345
346 *((__be16 *)buf) = cpu_to_be16(msglen);
347 pfx_iov.iov_base = buf;
348 pfx_iov.iov_len = sizeof(buf);
349 iov_iter_kvec(&pfx_iter, ITER_SOURCE, &pfx_iov, 1, pfx_iov.iov_len);
350
351 err = sk_msg_memcopy_from_iter(sk, &pfx_iter, &emsg->skmsg,
352 pfx_iov.iov_len);
353 if (err < 0)
354 goto fail;
355
356 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, &emsg->skmsg, size);
357 if (err < 0)
358 goto fail;
359
360 end = emsg->skmsg.sg.end;
361 emsg->len = size;
362 sk_msg_iter_var_prev(end);
363 sg_mark_end(sk_msg_elem(&emsg->skmsg, end));
364
365 tcp_rate_check_app_limited(sk);
366
367 err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT);
368 /* this message could be partially sent, keep it */
369
370 release_sock(sk);
371
372 return size;
373
374 fail:
375 sk_msg_free(sk, &emsg->skmsg);
376 memset(emsg, 0, sizeof(*emsg));
377 unlock:
378 release_sock(sk);
379 return err;
380 }
381
382 static struct proto espintcp_prot __ro_after_init;
383 static struct proto_ops espintcp_ops __ro_after_init;
384 static struct proto espintcp6_prot;
385 static struct proto_ops espintcp6_ops;
386 static DEFINE_MUTEX(tcpv6_prot_mutex);
387
espintcp_data_ready(struct sock * sk)388 static void espintcp_data_ready(struct sock *sk)
389 {
390 struct espintcp_ctx *ctx = espintcp_getctx(sk);
391
392 trace_sk_data_ready(sk);
393
394 strp_data_ready(&ctx->strp);
395 }
396
espintcp_tx_work(struct work_struct * work)397 static void espintcp_tx_work(struct work_struct *work)
398 {
399 struct espintcp_ctx *ctx = container_of(work,
400 struct espintcp_ctx, work);
401 struct sock *sk = ctx->strp.sk;
402
403 lock_sock(sk);
404 if (!ctx->tx_running)
405 espintcp_push_msgs(sk, 0);
406 release_sock(sk);
407 }
408
espintcp_write_space(struct sock * sk)409 static void espintcp_write_space(struct sock *sk)
410 {
411 struct espintcp_ctx *ctx = espintcp_getctx(sk);
412
413 schedule_work(&ctx->work);
414 ctx->saved_write_space(sk);
415 }
416
espintcp_destruct(struct sock * sk)417 static void espintcp_destruct(struct sock *sk)
418 {
419 struct espintcp_ctx *ctx = espintcp_getctx(sk);
420
421 ctx->saved_destruct(sk);
422 kfree(ctx);
423 }
424
tcp_is_ulp_esp(struct sock * sk)425 bool tcp_is_ulp_esp(struct sock *sk)
426 {
427 return sk->sk_prot == &espintcp_prot || sk->sk_prot == &espintcp6_prot;
428 }
429 EXPORT_SYMBOL_GPL(tcp_is_ulp_esp);
430
431 static void build_protos(struct proto *espintcp_prot,
432 struct proto_ops *espintcp_ops,
433 const struct proto *orig_prot,
434 const struct proto_ops *orig_ops);
espintcp_init_sk(struct sock * sk)435 static int espintcp_init_sk(struct sock *sk)
436 {
437 struct inet_connection_sock *icsk = inet_csk(sk);
438 struct strp_callbacks cb = {
439 .rcv_msg = espintcp_rcv,
440 .parse_msg = espintcp_parse,
441 };
442 struct espintcp_ctx *ctx;
443 int err;
444
445 /* sockmap is not compatible with espintcp */
446 if (sk->sk_user_data)
447 return -EBUSY;
448
449 ctx = kzalloc_obj(*ctx);
450 if (!ctx)
451 return -ENOMEM;
452
453 err = strp_init(&ctx->strp, sk, &cb);
454 if (err)
455 goto free;
456
457 __sk_dst_reset(sk);
458
459 strp_check_rcv(&ctx->strp);
460 skb_queue_head_init(&ctx->ike_queue);
461 skb_queue_head_init(&ctx->out_queue);
462
463 if (sk->sk_family == AF_INET) {
464 sk->sk_prot = &espintcp_prot;
465 sk->sk_socket->ops = &espintcp_ops;
466 } else {
467 mutex_lock(&tcpv6_prot_mutex);
468 if (!espintcp6_prot.recvmsg)
469 build_protos(&espintcp6_prot, &espintcp6_ops, sk->sk_prot, sk->sk_socket->ops);
470 mutex_unlock(&tcpv6_prot_mutex);
471
472 sk->sk_prot = &espintcp6_prot;
473 sk->sk_socket->ops = &espintcp6_ops;
474 }
475 ctx->saved_data_ready = sk->sk_data_ready;
476 ctx->saved_write_space = sk->sk_write_space;
477 ctx->saved_destruct = sk->sk_destruct;
478 sk->sk_data_ready = espintcp_data_ready;
479 sk->sk_write_space = espintcp_write_space;
480 sk->sk_destruct = espintcp_destruct;
481 rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
482 INIT_WORK(&ctx->work, espintcp_tx_work);
483
484 /* avoid using task_frag */
485 sk->sk_allocation = GFP_ATOMIC;
486 sk->sk_use_task_frag = false;
487
488 return 0;
489
490 free:
491 kfree(ctx);
492 return err;
493 }
494
espintcp_release(struct sock * sk)495 static void espintcp_release(struct sock *sk)
496 {
497 struct espintcp_ctx *ctx = espintcp_getctx(sk);
498 struct sk_buff_head queue;
499 struct sk_buff *skb;
500
501 __skb_queue_head_init(&queue);
502 skb_queue_splice_init(&ctx->out_queue, &queue);
503
504 while ((skb = __skb_dequeue(&queue)))
505 espintcp_push_skb(sk, skb);
506
507 tcp_release_cb(sk);
508 }
509
espintcp_close(struct sock * sk,long timeout)510 static void espintcp_close(struct sock *sk, long timeout)
511 {
512 struct espintcp_ctx *ctx = espintcp_getctx(sk);
513 struct espintcp_msg *emsg = &ctx->partial;
514
515 strp_stop(&ctx->strp);
516
517 sk->sk_prot = &tcp_prot;
518 barrier();
519
520 disable_work_sync(&ctx->work);
521 strp_done(&ctx->strp);
522
523 skb_queue_purge(&ctx->out_queue);
524 skb_queue_purge(&ctx->ike_queue);
525
526 if (emsg->len) {
527 if (emsg->skb)
528 kfree_skb(emsg->skb);
529 else
530 sk_msg_free(sk, &emsg->skmsg);
531 }
532
533 tcp_close(sk, timeout);
534 }
535
espintcp_poll(struct file * file,struct socket * sock,poll_table * wait)536 static __poll_t espintcp_poll(struct file *file, struct socket *sock,
537 poll_table *wait)
538 {
539 struct sock *sk = sock->sk;
540 struct espintcp_ctx *ctx = espintcp_getctx(sk);
541
542 return datagram_poll_queue(file, sock, wait, &ctx->ike_queue);
543 }
544
build_protos(struct proto * espintcp_prot,struct proto_ops * espintcp_ops,const struct proto * orig_prot,const struct proto_ops * orig_ops)545 static void build_protos(struct proto *espintcp_prot,
546 struct proto_ops *espintcp_ops,
547 const struct proto *orig_prot,
548 const struct proto_ops *orig_ops)
549 {
550 memcpy(espintcp_prot, orig_prot, sizeof(struct proto));
551 memcpy(espintcp_ops, orig_ops, sizeof(struct proto_ops));
552 espintcp_prot->sendmsg = espintcp_sendmsg;
553 espintcp_prot->recvmsg = espintcp_recvmsg;
554 espintcp_prot->close = espintcp_close;
555 espintcp_prot->release_cb = espintcp_release;
556 espintcp_ops->poll = espintcp_poll;
557 }
558
559 static struct tcp_ulp_ops espintcp_ulp __read_mostly = {
560 .name = "espintcp",
561 .owner = THIS_MODULE,
562 .init = espintcp_init_sk,
563 };
564
espintcp_init(void)565 void __init espintcp_init(void)
566 {
567 build_protos(&espintcp_prot, &espintcp_ops, &tcp_prot, &inet_stream_ops);
568
569 tcp_register_ulp(&espintcp_ulp);
570 }
571