1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* connection-level event handling
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/module.h>
11 #include <linux/net.h>
12 #include <linux/skbuff.h>
13 #include <linux/errqueue.h>
14 #include <net/sock.h>
15 #include <net/af_rxrpc.h>
16 #include <net/ip.h>
17 #include "ar-internal.h"
18
19 /*
20 * Set the completion state on an aborted connection.
21 */
rxrpc_set_conn_aborted(struct rxrpc_connection * conn,s32 abort_code,int err,enum rxrpc_call_completion compl)22 static bool rxrpc_set_conn_aborted(struct rxrpc_connection *conn,
23 s32 abort_code, int err,
24 enum rxrpc_call_completion compl)
25 {
26 bool aborted = false;
27
28 if (conn->state != RXRPC_CONN_ABORTED) {
29 spin_lock_irq(&conn->state_lock);
30 if (conn->state != RXRPC_CONN_ABORTED) {
31 conn->abort_code = abort_code;
32 conn->error = err;
33 conn->completion = compl;
34 /* Order the abort info before the state change. */
35 smp_store_release(&conn->state, RXRPC_CONN_ABORTED);
36 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
37 set_bit(RXRPC_CONN_EV_ABORT_CALLS, &conn->events);
38 aborted = true;
39 }
40 spin_unlock_irq(&conn->state_lock);
41 }
42
43 return aborted;
44 }
45
46 /*
47 * Mark a socket buffer to indicate that the connection it's on should be aborted.
48 */
rxrpc_abort_conn(struct rxrpc_connection * conn,struct sk_buff * skb,s32 abort_code,int err,enum rxrpc_abort_reason why)49 int rxrpc_abort_conn(struct rxrpc_connection *conn, struct sk_buff *skb,
50 s32 abort_code, int err, enum rxrpc_abort_reason why)
51 {
52
53 u32 cid = conn->proto.cid, call = 0, seq = 0;
54
55 if (skb) {
56 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
57
58 cid = sp->hdr.cid;
59 call = sp->hdr.callNumber;
60 seq = sp->hdr.seq;
61 }
62
63 if (rxrpc_set_conn_aborted(conn, abort_code, err,
64 RXRPC_CALL_LOCALLY_ABORTED)) {
65 trace_rxrpc_abort(0, why, cid, call, seq, abort_code, err);
66 rxrpc_poke_conn(conn, rxrpc_conn_get_poke_abort);
67 }
68 return -EPROTO;
69 }
70
71 /*
72 * Mark a connection as being remotely aborted.
73 */
rxrpc_input_conn_abort(struct rxrpc_connection * conn,struct sk_buff * skb)74 static void rxrpc_input_conn_abort(struct rxrpc_connection *conn,
75 struct sk_buff *skb)
76 {
77 trace_rxrpc_rx_conn_abort(conn, skb);
78 rxrpc_set_conn_aborted(conn, skb->priority, -ECONNABORTED,
79 RXRPC_CALL_REMOTELY_ABORTED);
80 }
81
82 /*
83 * Retransmit terminal ACK or ABORT of the previous call.
84 */
rxrpc_conn_retransmit_call(struct rxrpc_connection * conn,struct sk_buff * skb,unsigned int channel)85 void rxrpc_conn_retransmit_call(struct rxrpc_connection *conn,
86 struct sk_buff *skb,
87 unsigned int channel)
88 {
89 struct rxrpc_skb_priv *sp = skb ? rxrpc_skb(skb) : NULL;
90 struct rxrpc_channel *chan;
91 struct msghdr msg;
92 struct kvec iov[3];
93 struct {
94 struct rxrpc_wire_header whdr;
95 union {
96 __be32 abort_code;
97 struct rxrpc_ackpacket ack;
98 };
99 } __attribute__((packed)) pkt;
100 struct rxrpc_acktrailer trailer;
101 size_t len;
102 int ret, ioc;
103 u32 serial, max_mtu, if_mtu, call_id, padding;
104
105 _enter("%d", conn->debug_id);
106
107 if (sp && sp->hdr.type == RXRPC_PACKET_TYPE_ACK) {
108 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
109 &pkt.ack, sizeof(pkt.ack)) < 0)
110 return;
111 if (pkt.ack.reason == RXRPC_ACK_PING_RESPONSE)
112 return;
113 }
114
115 chan = &conn->channels[channel];
116
117 /* If the last call got moved on whilst we were waiting to run, just
118 * ignore this packet.
119 */
120 call_id = chan->last_call;
121 if (skb && call_id != sp->hdr.callNumber)
122 return;
123
124 msg.msg_name = &conn->peer->srx.transport;
125 msg.msg_namelen = conn->peer->srx.transport_len;
126 msg.msg_control = NULL;
127 msg.msg_controllen = 0;
128 msg.msg_flags = 0;
129
130 iov[0].iov_base = &pkt;
131 iov[0].iov_len = sizeof(pkt.whdr);
132 iov[1].iov_base = &padding;
133 iov[1].iov_len = 3;
134 iov[2].iov_base = &trailer;
135 iov[2].iov_len = sizeof(trailer);
136
137 serial = rxrpc_get_next_serial(conn);
138
139 pkt.whdr.epoch = htonl(conn->proto.epoch);
140 pkt.whdr.cid = htonl(conn->proto.cid | channel);
141 pkt.whdr.callNumber = htonl(call_id);
142 pkt.whdr.serial = htonl(serial);
143 pkt.whdr.seq = 0;
144 pkt.whdr.type = chan->last_type;
145 pkt.whdr.flags = conn->out_clientflag;
146 pkt.whdr.userStatus = 0;
147 pkt.whdr.securityIndex = conn->security_ix;
148 pkt.whdr._rsvd = 0;
149 pkt.whdr.serviceId = htons(conn->service_id);
150
151 len = sizeof(pkt.whdr);
152 switch (chan->last_type) {
153 case RXRPC_PACKET_TYPE_ABORT:
154 pkt.abort_code = htonl(chan->last_abort);
155 iov[0].iov_len += sizeof(pkt.abort_code);
156 len += sizeof(pkt.abort_code);
157 ioc = 1;
158 break;
159
160 case RXRPC_PACKET_TYPE_ACK:
161 if_mtu = conn->peer->if_mtu - conn->peer->hdrsize;
162 if (conn->peer->ackr_adv_pmtud) {
163 max_mtu = umax(conn->peer->max_data, rxrpc_rx_mtu);
164 } else {
165 if_mtu = umin(1444, if_mtu);
166 max_mtu = if_mtu;
167 }
168 pkt.ack.bufferSpace = 0;
169 pkt.ack.maxSkew = htons(skb ? skb->priority : 0);
170 pkt.ack.firstPacket = htonl(chan->last_seq + 1);
171 pkt.ack.previousPacket = htonl(chan->last_seq);
172 pkt.ack.serial = htonl(skb ? sp->hdr.serial : 0);
173 pkt.ack.reason = skb ? RXRPC_ACK_DUPLICATE : RXRPC_ACK_IDLE;
174 pkt.ack.nAcks = 0;
175 trailer.maxMTU = htonl(max_mtu);
176 trailer.ifMTU = htonl(if_mtu);
177 trailer.rwind = htonl(rxrpc_rx_window_size);
178 trailer.jumbo_max = 0;
179 pkt.whdr.flags |= RXRPC_SLOW_START_OK;
180 padding = 0;
181 iov[0].iov_len += sizeof(pkt.ack);
182 len += sizeof(pkt.ack) + 3 + sizeof(trailer);
183 ioc = 3;
184
185 trace_rxrpc_tx_ack(chan->call_debug_id, serial,
186 ntohl(pkt.ack.firstPacket),
187 ntohl(pkt.ack.serial),
188 pkt.ack.reason, 0, rxrpc_rx_window_size,
189 rxrpc_propose_ack_retransmit);
190 break;
191
192 default:
193 return;
194 }
195
196 ret = kernel_sendmsg(conn->local->socket, &msg, iov, ioc, len);
197 rxrpc_peer_mark_tx(conn->peer);
198 if (ret < 0)
199 trace_rxrpc_tx_fail(chan->call_debug_id, serial, ret,
200 rxrpc_tx_point_call_final_resend);
201 else
202 trace_rxrpc_tx_packet(chan->call_debug_id, &pkt.whdr,
203 rxrpc_tx_point_call_final_resend);
204
205 _leave("");
206 }
207
208 /*
209 * pass a connection-level abort onto all calls on that connection
210 */
rxrpc_abort_calls(struct rxrpc_connection * conn)211 static void rxrpc_abort_calls(struct rxrpc_connection *conn)
212 {
213 struct rxrpc_call *call;
214 int i;
215
216 _enter("{%d},%x", conn->debug_id, conn->abort_code);
217
218 for (i = 0; i < RXRPC_MAXCALLS; i++) {
219 call = conn->channels[i].call;
220 if (call) {
221 rxrpc_see_call(call, rxrpc_call_see_conn_abort);
222 rxrpc_set_call_completion(call,
223 conn->completion,
224 conn->abort_code,
225 conn->error);
226 rxrpc_poke_call(call, rxrpc_call_poke_conn_abort);
227 }
228 }
229
230 _leave("");
231 }
232
233 /*
234 * mark a call as being on a now-secured channel
235 * - must be called with BH's disabled.
236 */
rxrpc_call_is_secure(struct rxrpc_call * call)237 static void rxrpc_call_is_secure(struct rxrpc_call *call)
238 {
239 if (call && __test_and_clear_bit(RXRPC_CALL_CONN_CHALLENGING, &call->flags))
240 rxrpc_notify_socket(call);
241 }
242
rxrpc_verify_response(struct rxrpc_connection * conn,struct sk_buff * skb)243 static int rxrpc_verify_response(struct rxrpc_connection *conn,
244 struct sk_buff *skb)
245 {
246 unsigned int len = skb->len - sizeof(struct rxrpc_wire_header);
247 void *buffer;
248 int ret;
249
250 buffer = kmalloc(len, GFP_NOFS);
251 if (!buffer)
252 return -ENOMEM;
253
254 ret = skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), buffer, len);
255 if (ret < 0)
256 goto out;
257
258 ret = conn->security->verify_response(conn, skb, buffer, len);
259
260 out:
261 kfree(buffer);
262 return ret;
263 }
264
265 /*
266 * connection-level Rx packet processor
267 */
rxrpc_process_event(struct rxrpc_connection * conn,struct sk_buff * skb)268 static int rxrpc_process_event(struct rxrpc_connection *conn,
269 struct sk_buff *skb)
270 {
271 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
272 bool secured = false;
273 int ret;
274
275 if (conn->state == RXRPC_CONN_ABORTED)
276 return -ECONNABORTED;
277
278 _enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
279
280 switch (sp->hdr.type) {
281 case RXRPC_PACKET_TYPE_CHALLENGE:
282 ret = conn->security->respond_to_challenge(conn, skb);
283 sp->chall.conn = NULL;
284 rxrpc_put_connection(conn, rxrpc_conn_put_challenge_input);
285 return ret;
286
287 case RXRPC_PACKET_TYPE_RESPONSE:
288 spin_lock_irq(&conn->state_lock);
289 if (conn->state != RXRPC_CONN_SERVICE_CHALLENGING) {
290 spin_unlock_irq(&conn->state_lock);
291 return 0;
292 }
293 spin_unlock_irq(&conn->state_lock);
294
295 ret = rxrpc_verify_response(conn, skb);
296 if (ret < 0)
297 return ret;
298
299 ret = conn->security->init_connection_security(
300 conn, conn->key->payload.data[0]);
301 if (ret < 0)
302 return ret;
303
304 spin_lock_irq(&conn->state_lock);
305 if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
306 conn->state = RXRPC_CONN_SERVICE;
307 secured = true;
308 }
309 spin_unlock_irq(&conn->state_lock);
310
311 if (secured) {
312 /* Offload call state flipping to the I/O thread. As
313 * we've already received the packet, put it on the
314 * front of the queue.
315 */
316 sp->poke_conn = rxrpc_get_connection(
317 conn, rxrpc_conn_get_poke_secured);
318 skb->mark = RXRPC_SKB_MARK_SERVICE_CONN_SECURED;
319 rxrpc_get_skb(skb, rxrpc_skb_get_conn_secured);
320 skb_queue_head(&conn->local->rx_queue, skb);
321 rxrpc_wake_up_io_thread(conn->local);
322 }
323 return 0;
324
325 default:
326 WARN_ON_ONCE(1);
327 return -EPROTO;
328 }
329 }
330
331 /*
332 * set up security and issue a challenge
333 */
rxrpc_secure_connection(struct rxrpc_connection * conn)334 static void rxrpc_secure_connection(struct rxrpc_connection *conn)
335 {
336 if (conn->security->issue_challenge(conn) < 0)
337 rxrpc_abort_conn(conn, NULL, RX_CALL_DEAD, -ENOMEM,
338 rxrpc_abort_nomem);
339 }
340
341 /*
342 * Process delayed final ACKs that we haven't subsumed into a subsequent call.
343 */
rxrpc_process_delayed_final_acks(struct rxrpc_connection * conn,bool force)344 void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn, bool force)
345 {
346 unsigned long j = jiffies, next_j;
347 unsigned int channel;
348 bool set;
349
350 again:
351 next_j = j + LONG_MAX;
352 set = false;
353 for (channel = 0; channel < RXRPC_MAXCALLS; channel++) {
354 struct rxrpc_channel *chan = &conn->channels[channel];
355 unsigned long ack_at;
356
357 if (!test_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags))
358 continue;
359
360 ack_at = chan->final_ack_at;
361 if (time_before(j, ack_at) && !force) {
362 if (time_before(ack_at, next_j)) {
363 next_j = ack_at;
364 set = true;
365 }
366 continue;
367 }
368
369 if (test_and_clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel,
370 &conn->flags))
371 rxrpc_conn_retransmit_call(conn, NULL, channel);
372 }
373
374 j = jiffies;
375 if (time_before_eq(next_j, j))
376 goto again;
377 if (set)
378 rxrpc_reduce_conn_timer(conn, next_j);
379 }
380
381 /*
382 * connection-level event processor
383 */
rxrpc_do_process_connection(struct rxrpc_connection * conn)384 static void rxrpc_do_process_connection(struct rxrpc_connection *conn)
385 {
386 struct sk_buff *skb;
387
388 if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
389 rxrpc_secure_connection(conn);
390
391 /* go through the conn-level event packets, releasing the ref on this
392 * connection that each one has when we've finished with it */
393 while ((skb = skb_dequeue(&conn->rx_queue))) {
394 rxrpc_see_skb(skb, rxrpc_skb_see_conn_work);
395 rxrpc_process_event(conn, skb);
396 rxrpc_free_skb(skb, rxrpc_skb_put_conn_work);
397 }
398 }
399
rxrpc_process_connection(struct work_struct * work)400 void rxrpc_process_connection(struct work_struct *work)
401 {
402 struct rxrpc_connection *conn =
403 container_of(work, struct rxrpc_connection, processor);
404
405 rxrpc_see_connection(conn, rxrpc_conn_see_work);
406
407 if (__rxrpc_use_local(conn->local, rxrpc_local_use_conn_work)) {
408 rxrpc_do_process_connection(conn);
409 rxrpc_unuse_local(conn->local, rxrpc_local_unuse_conn_work);
410 }
411 }
412
413 /*
414 * post connection-level events to the connection
415 * - this includes challenges, responses, some aborts and call terminal packet
416 * retransmission.
417 */
rxrpc_post_packet_to_conn(struct rxrpc_connection * conn,struct sk_buff * skb)418 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
419 struct sk_buff *skb)
420 {
421 _enter("%p,%p", conn, skb);
422
423 rxrpc_get_skb(skb, rxrpc_skb_get_conn_work);
424 skb_queue_tail(&conn->rx_queue, skb);
425 rxrpc_queue_conn(conn, rxrpc_conn_queue_rx_work);
426 }
427
428 /*
429 * Post a CHALLENGE packet to the socket of one of a connection's calls so that
430 * it can get application data to include in the packet, possibly querying
431 * userspace.
432 */
rxrpc_post_challenge(struct rxrpc_connection * conn,struct sk_buff * skb)433 static bool rxrpc_post_challenge(struct rxrpc_connection *conn,
434 struct sk_buff *skb)
435 {
436 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
437 struct rxrpc_call *call = NULL;
438 struct rxrpc_sock *rx;
439 bool respond = false;
440
441 sp->chall.conn =
442 rxrpc_get_connection(conn, rxrpc_conn_get_challenge_input);
443
444 if (!conn->security->challenge_to_recvmsg) {
445 rxrpc_post_packet_to_conn(conn, skb);
446 return true;
447 }
448
449 rcu_read_lock();
450
451 for (int i = 0; i < ARRAY_SIZE(conn->channels); i++) {
452 if (conn->channels[i].call) {
453 call = conn->channels[i].call;
454 rx = rcu_dereference(call->socket);
455 if (!rx) {
456 call = NULL;
457 continue;
458 }
459
460 respond = true;
461 if (test_bit(RXRPC_SOCK_MANAGE_RESPONSE, &rx->flags))
462 break;
463 call = NULL;
464 }
465 }
466
467 if (!respond) {
468 rcu_read_unlock();
469 rxrpc_put_connection(conn, rxrpc_conn_put_challenge_input);
470 sp->chall.conn = NULL;
471 return false;
472 }
473
474 if (call)
475 rxrpc_notify_socket_oob(call, skb);
476 rcu_read_unlock();
477
478 if (!call)
479 rxrpc_post_packet_to_conn(conn, skb);
480 return true;
481 }
482
483 /*
484 * Input a connection-level packet.
485 */
rxrpc_input_conn_packet(struct rxrpc_connection * conn,struct sk_buff * skb)486 bool rxrpc_input_conn_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
487 {
488 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
489
490 switch (sp->hdr.type) {
491 case RXRPC_PACKET_TYPE_BUSY:
492 /* Just ignore BUSY packets for now. */
493 return true;
494
495 case RXRPC_PACKET_TYPE_ABORT:
496 if (rxrpc_is_conn_aborted(conn))
497 return true;
498 rxrpc_input_conn_abort(conn, skb);
499 rxrpc_abort_calls(conn);
500 return true;
501
502 case RXRPC_PACKET_TYPE_CHALLENGE:
503 rxrpc_see_skb(skb, rxrpc_skb_see_oob_challenge);
504 if (rxrpc_is_conn_aborted(conn)) {
505 if (conn->completion == RXRPC_CALL_LOCALLY_ABORTED)
506 rxrpc_send_conn_abort(conn);
507 return true;
508 }
509 if (!conn->security->validate_challenge(conn, skb))
510 return false;
511 return rxrpc_post_challenge(conn, skb);
512
513 case RXRPC_PACKET_TYPE_RESPONSE:
514 if (rxrpc_is_conn_aborted(conn)) {
515 if (conn->completion == RXRPC_CALL_LOCALLY_ABORTED)
516 rxrpc_send_conn_abort(conn);
517 return true;
518 }
519 rxrpc_post_packet_to_conn(conn, skb);
520 return true;
521
522 default:
523 WARN_ON_ONCE(1);
524 return true;
525 }
526 }
527
528 /*
529 * Input a connection event.
530 */
rxrpc_input_conn_event(struct rxrpc_connection * conn,struct sk_buff * skb)531 void rxrpc_input_conn_event(struct rxrpc_connection *conn, struct sk_buff *skb)
532 {
533 unsigned int loop;
534
535 if (test_and_clear_bit(RXRPC_CONN_EV_ABORT_CALLS, &conn->events))
536 rxrpc_abort_calls(conn);
537
538 if (conn->tx_response) {
539 struct sk_buff *skb;
540
541 spin_lock_irq(&conn->local->lock);
542 skb = conn->tx_response;
543 conn->tx_response = NULL;
544 spin_unlock_irq(&conn->local->lock);
545
546 if (conn->state != RXRPC_CONN_ABORTED)
547 rxrpc_send_response(conn, skb);
548 rxrpc_free_skb(skb, rxrpc_skb_put_response);
549 }
550
551 if (skb) {
552 switch (skb->mark) {
553 case RXRPC_SKB_MARK_SERVICE_CONN_SECURED:
554 if (conn->state != RXRPC_CONN_SERVICE)
555 break;
556
557 for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
558 rxrpc_call_is_secure(conn->channels[loop].call);
559 break;
560 }
561 }
562
563 /* Process delayed ACKs whose time has come. */
564 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
565 rxrpc_process_delayed_final_acks(conn, false);
566 }
567
568 /*
569 * Post a RESPONSE message to the I/O thread for transmission.
570 */
rxrpc_post_response(struct rxrpc_connection * conn,struct sk_buff * skb)571 void rxrpc_post_response(struct rxrpc_connection *conn, struct sk_buff *skb)
572 {
573 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
574 struct rxrpc_local *local = conn->local;
575 struct sk_buff *old;
576
577 _enter("%x", sp->resp.challenge_serial);
578
579 spin_lock_irq(&local->lock);
580 old = conn->tx_response;
581 if (old) {
582 struct rxrpc_skb_priv *osp = rxrpc_skb(old);
583
584 /* Always go with the response to the most recent challenge. */
585 if (after(sp->resp.challenge_serial, osp->resp.challenge_serial))
586 conn->tx_response = skb;
587 else
588 old = skb;
589 } else {
590 conn->tx_response = skb;
591 }
592 spin_unlock_irq(&local->lock);
593 rxrpc_poke_conn(conn, rxrpc_conn_get_poke_response);
594 rxrpc_free_skb(old, rxrpc_skb_put_old_response);
595 }
596