1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2 /* isotp.c - ISO 15765-2 CAN transport protocol for protocol family CAN
3 *
4 * This implementation does not provide ISO-TP specific return values to the
5 * userspace.
6 *
7 * - RX path timeout of data reception leads to -ETIMEDOUT
8 * - RX path SN mismatch leads to -EILSEQ
9 * - RX path data reception with wrong padding leads to -EBADMSG
10 * - TX path flowcontrol reception timeout leads to -ECOMM
11 * - TX path flowcontrol reception overflow leads to -EMSGSIZE
12 * - TX path flowcontrol reception with wrong layout/padding leads to -EBADMSG
13 * - when a transfer (tx) is on the run the next write() blocks until it's done
14 * - use CAN_ISOTP_WAIT_TX_DONE flag to block the caller until the PDU is sent
15 * - as we have static buffers the check whether the PDU fits into the buffer
16 * is done at FF reception time (no support for sending 'wait frames')
17 *
18 * Copyright (c) 2020 Volkswagen Group Electronic Research
19 * All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 * 3. Neither the name of Volkswagen nor the names of its contributors
30 * may be used to endorse or promote products derived from this software
31 * without specific prior written permission.
32 *
33 * Alternatively, provided that this notice is retained in full, this
34 * software may be distributed under the terms of the GNU General
35 * Public License ("GPL") version 2, in which case the provisions of the
36 * GPL apply INSTEAD OF those given above.
37 *
38 * The provided data structures and external interfaces from this code
39 * are not restricted to be used by modules with a GPL compatible license.
40 *
41 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
42 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
43 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
44 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
45 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
48 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
49 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
50 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
51 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
52 * DAMAGE.
53 */
54
55 #include <linux/module.h>
56 #include <linux/init.h>
57 #include <linux/interrupt.h>
58 #include <linux/spinlock.h>
59 #include <linux/hrtimer.h>
60 #include <linux/wait.h>
61 #include <linux/uio.h>
62 #include <linux/net.h>
63 #include <linux/netdevice.h>
64 #include <linux/socket.h>
65 #include <linux/if_arp.h>
66 #include <linux/skbuff.h>
67 #include <linux/can.h>
68 #include <linux/can/core.h>
69 #include <linux/can/skb.h>
70 #include <linux/can/isotp.h>
71 #include <linux/slab.h>
72 #include <net/can.h>
73 #include <net/sock.h>
74 #include <net/net_namespace.h>
75
76 MODULE_DESCRIPTION("PF_CAN ISO 15765-2 transport protocol");
77 MODULE_LICENSE("Dual BSD/GPL");
78 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
79 MODULE_ALIAS("can-proto-6");
80
81 #define ISOTP_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_addr.tp)
82
83 #define SINGLE_MASK(id) (((id) & CAN_EFF_FLAG) ? \
84 (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
85 (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
86
87 /* Since ISO 15765-2:2016 the CAN isotp protocol supports more than 4095
88 * byte per ISO PDU as the FF_DL can take full 32 bit values (4 Gbyte).
89 * We would need some good concept to handle this between user space and
90 * kernel space. For now set the static buffer to something about 8 kbyte
91 * to be able to test this new functionality.
92 */
93 #define DEFAULT_MAX_PDU_SIZE 8300
94
95 /* maximum PDU size before ISO 15765-2:2016 extension was 4095 */
96 #define MAX_12BIT_PDU_SIZE 4095
97
98 /* limit the isotp pdu size from the optional module parameter to 1MByte */
99 #define MAX_PDU_SIZE (1025 * 1024U)
100
101 static unsigned int max_pdu_size __read_mostly = DEFAULT_MAX_PDU_SIZE;
102 module_param(max_pdu_size, uint, 0444);
103 MODULE_PARM_DESC(max_pdu_size, "maximum isotp pdu size (default "
104 __stringify(DEFAULT_MAX_PDU_SIZE) ")");
105
106 /* N_PCI type values in bits 7-4 of N_PCI bytes */
107 #define N_PCI_SF 0x00 /* single frame */
108 #define N_PCI_FF 0x10 /* first frame */
109 #define N_PCI_CF 0x20 /* consecutive frame */
110 #define N_PCI_FC 0x30 /* flow control */
111
112 #define N_PCI_SZ 1 /* size of the PCI byte #1 */
113 #define SF_PCI_SZ4 1 /* size of SingleFrame PCI including 4 bit SF_DL */
114 #define SF_PCI_SZ8 2 /* size of SingleFrame PCI including 8 bit SF_DL */
115 #define FF_PCI_SZ12 2 /* size of FirstFrame PCI including 12 bit FF_DL */
116 #define FF_PCI_SZ32 6 /* size of FirstFrame PCI including 32 bit FF_DL */
117 #define FC_CONTENT_SZ 3 /* flow control content size in byte (FS/BS/STmin) */
118
119 #define ISOTP_CHECK_PADDING (CAN_ISOTP_CHK_PAD_LEN | CAN_ISOTP_CHK_PAD_DATA)
120 #define ISOTP_ALL_BC_FLAGS (CAN_ISOTP_SF_BROADCAST | CAN_ISOTP_CF_BROADCAST)
121
122 /* Flow Status given in FC frame */
123 #define ISOTP_FC_CTS 0 /* clear to send */
124 #define ISOTP_FC_WT 1 /* wait */
125 #define ISOTP_FC_OVFLW 2 /* overflow */
126
127 #define ISOTP_FC_TIMEOUT 1 /* 1 sec */
128 #define ISOTP_ECHO_TIMEOUT 2 /* 2 secs */
129
130 enum {
131 ISOTP_IDLE = 0,
132 ISOTP_WAIT_FIRST_FC,
133 ISOTP_WAIT_FC,
134 ISOTP_WAIT_DATA,
135 ISOTP_SENDING,
136 ISOTP_SHUTDOWN,
137 };
138
139 struct tpcon {
140 u8 *buf;
141 unsigned int buflen;
142 unsigned int len;
143 unsigned int idx;
144 u32 state;
145 u8 bs;
146 u8 sn;
147 u8 ll_dl;
148 u8 sbuf[DEFAULT_MAX_PDU_SIZE];
149 };
150
151 struct isotp_sock {
152 struct sock sk;
153 int bound;
154 int ifindex;
155 canid_t txid;
156 canid_t rxid;
157 ktime_t tx_gap;
158 ktime_t lastrxcf_tstamp;
159 struct hrtimer rxtimer, txtimer, txfrtimer;
160 struct can_isotp_options opt;
161 struct can_isotp_fc_options rxfc, txfc;
162 struct can_isotp_ll_options ll;
163 u32 frame_txtime;
164 u32 force_tx_stmin;
165 u32 force_rx_stmin;
166 u32 cfecho; /* consecutive frame echo tag */
167 struct tpcon rx, tx;
168 struct list_head notifier;
169 wait_queue_head_t wait;
170 spinlock_t rx_lock; /* protect single thread state machine */
171 };
172
173 static LIST_HEAD(isotp_notifier_list);
174 static DEFINE_SPINLOCK(isotp_notifier_lock);
175 static struct isotp_sock *isotp_busy_notifier;
176
isotp_sk(const struct sock * sk)177 static inline struct isotp_sock *isotp_sk(const struct sock *sk)
178 {
179 return (struct isotp_sock *)sk;
180 }
181
isotp_bc_flags(struct isotp_sock * so)182 static u32 isotp_bc_flags(struct isotp_sock *so)
183 {
184 return so->opt.flags & ISOTP_ALL_BC_FLAGS;
185 }
186
isotp_register_rxid(struct isotp_sock * so)187 static bool isotp_register_rxid(struct isotp_sock *so)
188 {
189 /* no broadcast modes => register rx_id for FC frame reception */
190 return (isotp_bc_flags(so) == 0);
191 }
192
isotp_rx_timer_handler(struct hrtimer * hrtimer)193 static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)
194 {
195 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
196 rxtimer);
197 struct sock *sk = &so->sk;
198
199 if (so->rx.state == ISOTP_WAIT_DATA) {
200 /* we did not get new data frames in time */
201
202 /* report 'connection timed out' */
203 sk->sk_err = ETIMEDOUT;
204 if (!sock_flag(sk, SOCK_DEAD))
205 sk_error_report(sk);
206
207 /* reset rx state */
208 so->rx.state = ISOTP_IDLE;
209 }
210
211 return HRTIMER_NORESTART;
212 }
213
isotp_send_fc(struct sock * sk,int ae,u8 flowstatus)214 static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
215 {
216 struct net_device *dev;
217 struct sk_buff *nskb;
218 struct can_skb_ext *csx;
219 struct canfd_frame *ncf;
220 struct isotp_sock *so = isotp_sk(sk);
221 int can_send_ret;
222
223 nskb = alloc_skb(so->ll.mtu, gfp_any());
224 if (!nskb)
225 return 1;
226
227 csx = can_skb_ext_add(nskb);
228 if (!csx) {
229 kfree_skb(nskb);
230 return 1;
231 }
232
233 dev = dev_get_by_index(sock_net(sk), so->ifindex);
234 if (!dev) {
235 kfree_skb(nskb);
236 return 1;
237 }
238
239 csx->can_iif = dev->ifindex;
240 nskb->dev = dev;
241 can_skb_set_owner(nskb, sk);
242 ncf = (struct canfd_frame *)nskb->data;
243 skb_put_zero(nskb, so->ll.mtu);
244
245 /* create & send flow control reply */
246 ncf->can_id = so->txid;
247
248 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
249 memset(ncf->data, so->opt.txpad_content, CAN_MAX_DLEN);
250 ncf->len = CAN_MAX_DLEN;
251 } else {
252 ncf->len = ae + FC_CONTENT_SZ;
253 }
254
255 ncf->data[ae] = N_PCI_FC | flowstatus;
256 ncf->data[ae + 1] = so->rxfc.bs;
257 ncf->data[ae + 2] = so->rxfc.stmin;
258
259 if (ae)
260 ncf->data[0] = so->opt.ext_address;
261
262 ncf->flags = so->ll.tx_flags;
263
264 can_send_ret = can_send(nskb, 1);
265 if (can_send_ret)
266 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
267 __func__, ERR_PTR(can_send_ret));
268
269 dev_put(dev);
270
271 /* reset blocksize counter */
272 so->rx.bs = 0;
273
274 /* reset last CF frame rx timestamp for rx stmin enforcement */
275 so->lastrxcf_tstamp = ktime_set(0, 0);
276
277 /* start rx timeout watchdog */
278 hrtimer_start(&so->rxtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
279 HRTIMER_MODE_REL_SOFT);
280 return 0;
281 }
282
isotp_rcv_skb(struct sk_buff * skb,struct sock * sk)283 static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
284 {
285 struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
286 enum skb_drop_reason reason;
287
288 BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
289
290 memset(addr, 0, sizeof(*addr));
291 addr->can_family = AF_CAN;
292 addr->can_ifindex = skb->dev->ifindex;
293
294 reason = sock_queue_rcv_skb_reason(sk, skb);
295 if (reason)
296 sk_skb_reason_drop(sk, skb, reason);
297 }
298
padlen(u8 datalen)299 static u8 padlen(u8 datalen)
300 {
301 static const u8 plen[] = {
302 8, 8, 8, 8, 8, 8, 8, 8, 8, /* 0 - 8 */
303 12, 12, 12, 12, /* 9 - 12 */
304 16, 16, 16, 16, /* 13 - 16 */
305 20, 20, 20, 20, /* 17 - 20 */
306 24, 24, 24, 24, /* 21 - 24 */
307 32, 32, 32, 32, 32, 32, 32, 32, /* 25 - 32 */
308 48, 48, 48, 48, 48, 48, 48, 48, /* 33 - 40 */
309 48, 48, 48, 48, 48, 48, 48, 48 /* 41 - 48 */
310 };
311
312 if (datalen > 48)
313 return 64;
314
315 return plen[datalen];
316 }
317
318 /* check for length optimization and return 1/true when the check fails */
check_optimized(struct canfd_frame * cf,int start_index)319 static int check_optimized(struct canfd_frame *cf, int start_index)
320 {
321 /* for CAN_DL <= 8 the start_index is equal to the CAN_DL as the
322 * padding would start at this point. E.g. if the padding would
323 * start at cf.data[7] cf->len has to be 7 to be optimal.
324 * Note: The data[] index starts with zero.
325 */
326 if (cf->len <= CAN_MAX_DLEN)
327 return (cf->len != start_index);
328
329 /* This relation is also valid in the non-linear DLC range, where
330 * we need to take care of the minimal next possible CAN_DL.
331 * The correct check would be (padlen(cf->len) != padlen(start_index)).
332 * But as cf->len can only take discrete values from 12, .., 64 at this
333 * point the padlen(cf->len) is always equal to cf->len.
334 */
335 return (cf->len != padlen(start_index));
336 }
337
338 /* check padding and return 1/true when the check fails */
check_pad(struct isotp_sock * so,struct canfd_frame * cf,int start_index,u8 content)339 static int check_pad(struct isotp_sock *so, struct canfd_frame *cf,
340 int start_index, u8 content)
341 {
342 int i;
343
344 /* no RX_PADDING value => check length of optimized frame length */
345 if (!(so->opt.flags & CAN_ISOTP_RX_PADDING)) {
346 if (so->opt.flags & CAN_ISOTP_CHK_PAD_LEN)
347 return check_optimized(cf, start_index);
348
349 /* no valid test against empty value => ignore frame */
350 return 1;
351 }
352
353 /* check datalength of correctly padded CAN frame */
354 if ((so->opt.flags & CAN_ISOTP_CHK_PAD_LEN) &&
355 cf->len != padlen(cf->len))
356 return 1;
357
358 /* check padding content */
359 if (so->opt.flags & CAN_ISOTP_CHK_PAD_DATA) {
360 for (i = start_index; i < cf->len; i++)
361 if (cf->data[i] != content)
362 return 1;
363 }
364 return 0;
365 }
366
367 static void isotp_send_cframe(struct isotp_sock *so);
368
isotp_rcv_fc(struct isotp_sock * so,struct canfd_frame * cf,int ae)369 static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
370 {
371 struct sock *sk = &so->sk;
372
373 if (so->tx.state != ISOTP_WAIT_FC &&
374 so->tx.state != ISOTP_WAIT_FIRST_FC)
375 return 0;
376
377 hrtimer_cancel(&so->txtimer);
378
379 if ((cf->len < ae + FC_CONTENT_SZ) ||
380 ((so->opt.flags & ISOTP_CHECK_PADDING) &&
381 check_pad(so, cf, ae + FC_CONTENT_SZ, so->opt.rxpad_content))) {
382 /* malformed PDU - report 'not a data message' */
383 sk->sk_err = EBADMSG;
384 if (!sock_flag(sk, SOCK_DEAD))
385 sk_error_report(sk);
386
387 so->tx.state = ISOTP_IDLE;
388 wake_up_interruptible(&so->wait);
389 return 1;
390 }
391
392 /* get static/dynamic communication params from first/every FC frame */
393 if (so->tx.state == ISOTP_WAIT_FIRST_FC ||
394 so->opt.flags & CAN_ISOTP_DYN_FC_PARMS) {
395 so->txfc.bs = cf->data[ae + 1];
396 so->txfc.stmin = cf->data[ae + 2];
397
398 /* fix wrong STmin values according spec */
399 if (so->txfc.stmin > 0x7F &&
400 (so->txfc.stmin < 0xF1 || so->txfc.stmin > 0xF9))
401 so->txfc.stmin = 0x7F;
402
403 so->tx_gap = ktime_set(0, 0);
404 /* add transmission time for CAN frame N_As */
405 so->tx_gap = ktime_add_ns(so->tx_gap, so->frame_txtime);
406 /* add waiting time for consecutive frames N_Cs */
407 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
408 so->tx_gap = ktime_add_ns(so->tx_gap,
409 so->force_tx_stmin);
410 else if (so->txfc.stmin < 0x80)
411 so->tx_gap = ktime_add_ns(so->tx_gap,
412 so->txfc.stmin * 1000000);
413 else
414 so->tx_gap = ktime_add_ns(so->tx_gap,
415 (so->txfc.stmin - 0xF0)
416 * 100000);
417 so->tx.state = ISOTP_WAIT_FC;
418 }
419
420 switch (cf->data[ae] & 0x0F) {
421 case ISOTP_FC_CTS:
422 so->tx.bs = 0;
423 so->tx.state = ISOTP_SENDING;
424 /* send CF frame and enable echo timeout handling */
425 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
426 HRTIMER_MODE_REL_SOFT);
427 isotp_send_cframe(so);
428 break;
429
430 case ISOTP_FC_WT:
431 /* start timer to wait for next FC frame */
432 hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
433 HRTIMER_MODE_REL_SOFT);
434 break;
435
436 case ISOTP_FC_OVFLW:
437 /* overflow on receiver side - report 'message too long' */
438 sk->sk_err = EMSGSIZE;
439 if (!sock_flag(sk, SOCK_DEAD))
440 sk_error_report(sk);
441 fallthrough;
442
443 default:
444 /* stop this tx job */
445 so->tx.state = ISOTP_IDLE;
446 wake_up_interruptible(&so->wait);
447 }
448 return 0;
449 }
450
isotp_rcv_sf(struct sock * sk,struct canfd_frame * cf,int pcilen,struct sk_buff * skb,int len)451 static int isotp_rcv_sf(struct sock *sk, struct canfd_frame *cf, int pcilen,
452 struct sk_buff *skb, int len)
453 {
454 struct isotp_sock *so = isotp_sk(sk);
455 struct sk_buff *nskb;
456
457 hrtimer_cancel(&so->rxtimer);
458 so->rx.state = ISOTP_IDLE;
459
460 if (!len || len > cf->len - pcilen)
461 return 1;
462
463 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
464 check_pad(so, cf, pcilen + len, so->opt.rxpad_content)) {
465 /* malformed PDU - report 'not a data message' */
466 sk->sk_err = EBADMSG;
467 if (!sock_flag(sk, SOCK_DEAD))
468 sk_error_report(sk);
469 return 1;
470 }
471
472 nskb = alloc_skb(len, gfp_any());
473 if (!nskb)
474 return 1;
475
476 memcpy(skb_put(nskb, len), &cf->data[pcilen], len);
477
478 nskb->tstamp = skb->tstamp;
479 nskb->dev = skb->dev;
480 isotp_rcv_skb(nskb, sk);
481 return 0;
482 }
483
isotp_rcv_ff(struct sock * sk,struct canfd_frame * cf,int ae)484 static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
485 {
486 struct isotp_sock *so = isotp_sk(sk);
487 int i;
488 int off;
489 int ff_pci_sz;
490
491 hrtimer_cancel(&so->rxtimer);
492 so->rx.state = ISOTP_IDLE;
493
494 /* get the used sender LL_DL from the (first) CAN frame data length */
495 so->rx.ll_dl = padlen(cf->len);
496
497 /* the first frame has to use the entire frame up to LL_DL length */
498 if (cf->len != so->rx.ll_dl)
499 return 1;
500
501 /* get the FF_DL */
502 so->rx.len = (cf->data[ae] & 0x0F) << 8;
503 so->rx.len += cf->data[ae + 1];
504
505 /* Check for FF_DL escape sequence supporting 32 bit PDU length */
506 if (so->rx.len) {
507 ff_pci_sz = FF_PCI_SZ12;
508 } else {
509 /* FF_DL = 0 => get real length from next 4 bytes */
510 so->rx.len = cf->data[ae + 2] << 24;
511 so->rx.len += cf->data[ae + 3] << 16;
512 so->rx.len += cf->data[ae + 4] << 8;
513 so->rx.len += cf->data[ae + 5];
514 ff_pci_sz = FF_PCI_SZ32;
515 }
516
517 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
518 off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
519
520 if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
521 return 1;
522
523 /* PDU size > default => try max_pdu_size */
524 if (so->rx.len > so->rx.buflen && so->rx.buflen < max_pdu_size) {
525 u8 *newbuf = kmalloc(max_pdu_size, GFP_ATOMIC);
526
527 if (newbuf) {
528 so->rx.buf = newbuf;
529 so->rx.buflen = max_pdu_size;
530 }
531 }
532
533 if (so->rx.len > so->rx.buflen) {
534 /* send FC frame with overflow status */
535 isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
536 return 1;
537 }
538
539 /* copy the first received data bytes */
540 so->rx.idx = 0;
541 for (i = ae + ff_pci_sz; i < so->rx.ll_dl; i++)
542 so->rx.buf[so->rx.idx++] = cf->data[i];
543
544 /* initial setup for this pdu reception */
545 so->rx.sn = 1;
546 so->rx.state = ISOTP_WAIT_DATA;
547
548 /* no creation of flow control frames */
549 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
550 return 0;
551
552 /* send our first FC frame */
553 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
554 return 0;
555 }
556
isotp_rcv_cf(struct sock * sk,struct canfd_frame * cf,int ae,struct sk_buff * skb)557 static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
558 struct sk_buff *skb)
559 {
560 struct isotp_sock *so = isotp_sk(sk);
561 struct sk_buff *nskb;
562 int i;
563
564 if (so->rx.state != ISOTP_WAIT_DATA)
565 return 0;
566
567 /* drop if timestamp gap is less than force_rx_stmin nano secs */
568 if (so->opt.flags & CAN_ISOTP_FORCE_RXSTMIN) {
569 if (ktime_to_ns(ktime_sub(skb->tstamp, so->lastrxcf_tstamp)) <
570 so->force_rx_stmin)
571 return 0;
572
573 so->lastrxcf_tstamp = skb->tstamp;
574 }
575
576 hrtimer_cancel(&so->rxtimer);
577
578 /* CFs are never longer than the FF */
579 if (cf->len > so->rx.ll_dl)
580 return 1;
581
582 /* CFs have usually the LL_DL length */
583 if (cf->len < so->rx.ll_dl) {
584 /* this is only allowed for the last CF */
585 if (so->rx.len - so->rx.idx > so->rx.ll_dl - ae - N_PCI_SZ)
586 return 1;
587 }
588
589 if ((cf->data[ae] & 0x0F) != so->rx.sn) {
590 /* wrong sn detected - report 'illegal byte sequence' */
591 sk->sk_err = EILSEQ;
592 if (!sock_flag(sk, SOCK_DEAD))
593 sk_error_report(sk);
594
595 /* reset rx state */
596 so->rx.state = ISOTP_IDLE;
597 return 1;
598 }
599 so->rx.sn++;
600 so->rx.sn %= 16;
601
602 for (i = ae + N_PCI_SZ; i < cf->len; i++) {
603 so->rx.buf[so->rx.idx++] = cf->data[i];
604 if (so->rx.idx >= so->rx.len)
605 break;
606 }
607
608 if (so->rx.idx >= so->rx.len) {
609 /* we are done */
610 so->rx.state = ISOTP_IDLE;
611
612 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
613 check_pad(so, cf, i + 1, so->opt.rxpad_content)) {
614 /* malformed PDU - report 'not a data message' */
615 sk->sk_err = EBADMSG;
616 if (!sock_flag(sk, SOCK_DEAD))
617 sk_error_report(sk);
618 return 1;
619 }
620
621 nskb = alloc_skb(so->rx.len, gfp_any());
622 if (!nskb)
623 return 1;
624
625 memcpy(skb_put(nskb, so->rx.len), so->rx.buf,
626 so->rx.len);
627
628 nskb->tstamp = skb->tstamp;
629 nskb->dev = skb->dev;
630 isotp_rcv_skb(nskb, sk);
631 return 0;
632 }
633
634 /* perform blocksize handling, if enabled */
635 if (!so->rxfc.bs || ++so->rx.bs < so->rxfc.bs) {
636 /* start rx timeout watchdog */
637 hrtimer_start(&so->rxtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
638 HRTIMER_MODE_REL_SOFT);
639 return 0;
640 }
641
642 /* no creation of flow control frames */
643 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
644 return 0;
645
646 /* we reached the specified blocksize so->rxfc.bs */
647 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
648 return 0;
649 }
650
isotp_rcv(struct sk_buff * skb,void * data)651 static void isotp_rcv(struct sk_buff *skb, void *data)
652 {
653 struct sock *sk = (struct sock *)data;
654 struct isotp_sock *so = isotp_sk(sk);
655 struct canfd_frame *cf;
656 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
657 u8 n_pci_type, sf_dl;
658
659 /* Strictly receive only frames with the configured MTU size
660 * => clear separation of CAN2.0 / CAN FD transport channels
661 */
662 if (skb->len != so->ll.mtu)
663 return;
664
665 cf = (struct canfd_frame *)skb->data;
666
667 /* if enabled: check reception of my configured extended address */
668 if (ae && cf->data[0] != so->opt.rx_ext_address)
669 return;
670
671 n_pci_type = cf->data[ae] & 0xF0;
672
673 /* Make sure the state changes and data structures stay consistent at
674 * CAN frame reception time. This locking is not needed in real world
675 * use cases but the inconsistency can be triggered with syzkaller.
676 */
677 spin_lock(&so->rx_lock);
678
679 if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
680 /* check rx/tx path half duplex expectations */
681 if ((so->tx.state != ISOTP_IDLE && n_pci_type != N_PCI_FC) ||
682 (so->rx.state != ISOTP_IDLE && n_pci_type == N_PCI_FC))
683 goto out_unlock;
684 }
685
686 switch (n_pci_type) {
687 case N_PCI_FC:
688 /* tx path: flow control frame containing the FC parameters */
689 isotp_rcv_fc(so, cf, ae);
690 break;
691
692 case N_PCI_SF:
693 /* rx path: single frame
694 *
695 * As we do not have a rx.ll_dl configuration, we can only test
696 * if the CAN frames payload length matches the LL_DL == 8
697 * requirements - no matter if it's CAN 2.0 or CAN FD
698 */
699
700 /* get the SF_DL from the N_PCI byte */
701 sf_dl = cf->data[ae] & 0x0F;
702
703 if (cf->len <= CAN_MAX_DLEN) {
704 isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
705 } else {
706 if (can_is_canfd_skb(skb)) {
707 /* We have a CAN FD frame and CAN_DL is greater than 8:
708 * Only frames with the SF_DL == 0 ESC value are valid.
709 *
710 * If so take care of the increased SF PCI size
711 * (SF_PCI_SZ8) to point to the message content behind
712 * the extended SF PCI info and get the real SF_DL
713 * length value from the formerly first data byte.
714 */
715 if (sf_dl == 0)
716 isotp_rcv_sf(sk, cf, SF_PCI_SZ8 + ae, skb,
717 cf->data[SF_PCI_SZ4 + ae]);
718 }
719 }
720 break;
721
722 case N_PCI_FF:
723 /* rx path: first frame */
724 isotp_rcv_ff(sk, cf, ae);
725 break;
726
727 case N_PCI_CF:
728 /* rx path: consecutive frame */
729 isotp_rcv_cf(sk, cf, ae, skb);
730 break;
731 }
732
733 out_unlock:
734 spin_unlock(&so->rx_lock);
735 }
736
isotp_fill_dataframe(struct canfd_frame * cf,struct isotp_sock * so,int ae,int off)737 static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
738 int ae, int off)
739 {
740 int pcilen = N_PCI_SZ + ae + off;
741 int space = so->tx.ll_dl - pcilen;
742 int num = min_t(int, so->tx.len - so->tx.idx, space);
743 int i;
744
745 cf->can_id = so->txid;
746 cf->len = num + pcilen;
747
748 if (num < space) {
749 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
750 /* user requested padding */
751 cf->len = padlen(cf->len);
752 memset(cf->data, so->opt.txpad_content, cf->len);
753 } else if (cf->len > CAN_MAX_DLEN) {
754 /* mandatory padding for CAN FD frames */
755 cf->len = padlen(cf->len);
756 memset(cf->data, CAN_ISOTP_DEFAULT_PAD_CONTENT,
757 cf->len);
758 }
759 }
760
761 for (i = 0; i < num; i++)
762 cf->data[pcilen + i] = so->tx.buf[so->tx.idx++];
763
764 if (ae)
765 cf->data[0] = so->opt.ext_address;
766 }
767
isotp_send_cframe(struct isotp_sock * so)768 static void isotp_send_cframe(struct isotp_sock *so)
769 {
770 struct sock *sk = &so->sk;
771 struct sk_buff *skb;
772 struct can_skb_ext *csx;
773 struct net_device *dev;
774 struct canfd_frame *cf;
775 int can_send_ret;
776 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
777
778 dev = dev_get_by_index(sock_net(sk), so->ifindex);
779 if (!dev)
780 return;
781
782 skb = alloc_skb(so->ll.mtu, GFP_ATOMIC);
783 if (!skb) {
784 dev_put(dev);
785 return;
786 }
787
788 csx = can_skb_ext_add(skb);
789 if (!csx) {
790 kfree_skb(skb);
791 netdev_put(dev, NULL);
792 return;
793 }
794
795 csx->can_iif = dev->ifindex;
796
797 cf = (struct canfd_frame *)skb->data;
798 skb_put_zero(skb, so->ll.mtu);
799
800 /* create consecutive frame */
801 isotp_fill_dataframe(cf, so, ae, 0);
802
803 /* place consecutive frame N_PCI in appropriate index */
804 cf->data[ae] = N_PCI_CF | so->tx.sn++;
805 so->tx.sn %= 16;
806 so->tx.bs++;
807
808 cf->flags = so->ll.tx_flags;
809
810 skb->dev = dev;
811 can_skb_set_owner(skb, sk);
812
813 /* cfecho should have been zero'ed by init/isotp_rcv_echo() */
814 if (so->cfecho)
815 pr_notice_once("can-isotp: cfecho is %08X != 0\n", so->cfecho);
816
817 /* set consecutive frame echo tag */
818 so->cfecho = *(u32 *)cf->data;
819
820 /* send frame with local echo enabled */
821 can_send_ret = can_send(skb, 1);
822 if (can_send_ret) {
823 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
824 __func__, ERR_PTR(can_send_ret));
825 if (can_send_ret == -ENOBUFS)
826 pr_notice_once("can-isotp: tx queue is full\n");
827 }
828 dev_put(dev);
829 }
830
isotp_create_fframe(struct canfd_frame * cf,struct isotp_sock * so,int ae)831 static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
832 int ae)
833 {
834 int i;
835 int ff_pci_sz;
836
837 cf->can_id = so->txid;
838 cf->len = so->tx.ll_dl;
839 if (ae)
840 cf->data[0] = so->opt.ext_address;
841
842 /* create N_PCI bytes with 12/32 bit FF_DL data length */
843 if (so->tx.len > MAX_12BIT_PDU_SIZE) {
844 /* use 32 bit FF_DL notation */
845 cf->data[ae] = N_PCI_FF;
846 cf->data[ae + 1] = 0;
847 cf->data[ae + 2] = (u8)(so->tx.len >> 24) & 0xFFU;
848 cf->data[ae + 3] = (u8)(so->tx.len >> 16) & 0xFFU;
849 cf->data[ae + 4] = (u8)(so->tx.len >> 8) & 0xFFU;
850 cf->data[ae + 5] = (u8)so->tx.len & 0xFFU;
851 ff_pci_sz = FF_PCI_SZ32;
852 } else {
853 /* use 12 bit FF_DL notation */
854 cf->data[ae] = (u8)(so->tx.len >> 8) | N_PCI_FF;
855 cf->data[ae + 1] = (u8)so->tx.len & 0xFFU;
856 ff_pci_sz = FF_PCI_SZ12;
857 }
858
859 /* add first data bytes depending on ae */
860 for (i = ae + ff_pci_sz; i < so->tx.ll_dl; i++)
861 cf->data[i] = so->tx.buf[so->tx.idx++];
862
863 so->tx.sn = 1;
864 }
865
isotp_rcv_echo(struct sk_buff * skb,void * data)866 static void isotp_rcv_echo(struct sk_buff *skb, void *data)
867 {
868 struct sock *sk = (struct sock *)data;
869 struct isotp_sock *so = isotp_sk(sk);
870 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
871
872 /* only handle my own local echo CF/SF skb's (no FF!) */
873 if (skb->sk != sk || so->cfecho != *(u32 *)cf->data)
874 return;
875
876 /* cancel local echo timeout */
877 hrtimer_cancel(&so->txtimer);
878
879 /* local echo skb with consecutive frame has been consumed */
880 so->cfecho = 0;
881
882 if (so->tx.idx >= so->tx.len) {
883 /* we are done */
884 so->tx.state = ISOTP_IDLE;
885 wake_up_interruptible(&so->wait);
886 return;
887 }
888
889 if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
890 /* stop and wait for FC with timeout */
891 so->tx.state = ISOTP_WAIT_FC;
892 hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
893 HRTIMER_MODE_REL_SOFT);
894 return;
895 }
896
897 /* no gap between data frames needed => use burst mode */
898 if (!so->tx_gap) {
899 /* enable echo timeout handling */
900 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
901 HRTIMER_MODE_REL_SOFT);
902 isotp_send_cframe(so);
903 return;
904 }
905
906 /* start timer to send next consecutive frame with correct delay */
907 hrtimer_start(&so->txfrtimer, so->tx_gap, HRTIMER_MODE_REL_SOFT);
908 }
909
isotp_tx_timer_handler(struct hrtimer * hrtimer)910 static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
911 {
912 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
913 txtimer);
914 struct sock *sk = &so->sk;
915
916 /* don't handle timeouts in IDLE or SHUTDOWN state */
917 if (so->tx.state == ISOTP_IDLE || so->tx.state == ISOTP_SHUTDOWN)
918 return HRTIMER_NORESTART;
919
920 /* we did not get any flow control or echo frame in time */
921
922 /* report 'communication error on send' */
923 sk->sk_err = ECOMM;
924 if (!sock_flag(sk, SOCK_DEAD))
925 sk_error_report(sk);
926
927 /* reset tx state */
928 so->tx.state = ISOTP_IDLE;
929 wake_up_interruptible(&so->wait);
930
931 return HRTIMER_NORESTART;
932 }
933
isotp_txfr_timer_handler(struct hrtimer * hrtimer)934 static enum hrtimer_restart isotp_txfr_timer_handler(struct hrtimer *hrtimer)
935 {
936 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
937 txfrtimer);
938
939 /* start echo timeout handling and cover below protocol error */
940 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
941 HRTIMER_MODE_REL_SOFT);
942
943 /* cfecho should be consumed by isotp_rcv_echo() here */
944 if (so->tx.state == ISOTP_SENDING && !so->cfecho)
945 isotp_send_cframe(so);
946
947 return HRTIMER_NORESTART;
948 }
949
isotp_sendmsg(struct socket * sock,struct msghdr * msg,size_t size)950 static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
951 {
952 struct sock *sk = sock->sk;
953 struct isotp_sock *so = isotp_sk(sk);
954 struct sk_buff *skb;
955 struct can_skb_ext *csx;
956 struct net_device *dev;
957 struct canfd_frame *cf;
958 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
959 int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
960 s64 hrtimer_sec = ISOTP_ECHO_TIMEOUT;
961 int off;
962 int err;
963
964 if (!so->bound || so->tx.state == ISOTP_SHUTDOWN)
965 return -EADDRNOTAVAIL;
966
967 while (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE) {
968 /* we do not support multiple buffers - for now */
969 if (msg->msg_flags & MSG_DONTWAIT)
970 return -EAGAIN;
971
972 if (so->tx.state == ISOTP_SHUTDOWN)
973 return -EADDRNOTAVAIL;
974
975 /* wait for complete transmission of current pdu */
976 err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
977 if (err)
978 goto err_event_drop;
979 }
980
981 /* PDU size > default => try max_pdu_size */
982 if (size > so->tx.buflen && so->tx.buflen < max_pdu_size) {
983 u8 *newbuf = kmalloc(max_pdu_size, GFP_KERNEL);
984
985 if (newbuf) {
986 so->tx.buf = newbuf;
987 so->tx.buflen = max_pdu_size;
988 }
989 }
990
991 if (!size || size > so->tx.buflen) {
992 err = -EINVAL;
993 goto err_out_drop;
994 }
995
996 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
997 off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
998
999 /* does the given data fit into a single frame for SF_BROADCAST? */
1000 if ((isotp_bc_flags(so) == CAN_ISOTP_SF_BROADCAST) &&
1001 (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {
1002 err = -EINVAL;
1003 goto err_out_drop;
1004 }
1005
1006 err = memcpy_from_msg(so->tx.buf, msg, size);
1007 if (err < 0)
1008 goto err_out_drop;
1009
1010 dev = dev_get_by_index(sock_net(sk), so->ifindex);
1011 if (!dev) {
1012 err = -ENXIO;
1013 goto err_out_drop;
1014 }
1015
1016 skb = sock_alloc_send_skb(sk, so->ll.mtu, msg->msg_flags & MSG_DONTWAIT,
1017 &err);
1018 if (!skb) {
1019 dev_put(dev);
1020 goto err_out_drop;
1021 }
1022
1023 csx = can_skb_ext_add(skb);
1024 if (!csx) {
1025 kfree_skb(skb);
1026 netdev_put(dev, NULL);
1027 err = -ENOMEM;
1028 goto err_out_drop;
1029 }
1030
1031 csx->can_iif = dev->ifindex;
1032
1033 so->tx.len = size;
1034 so->tx.idx = 0;
1035
1036 cf = (struct canfd_frame *)skb->data;
1037 skb_put_zero(skb, so->ll.mtu);
1038
1039 /* cfecho should have been zero'ed by init / former isotp_rcv_echo() */
1040 if (so->cfecho)
1041 pr_notice_once("can-isotp: uninit cfecho %08X\n", so->cfecho);
1042
1043 /* check for single frame transmission depending on TX_DL */
1044 if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
1045 /* The message size generally fits into a SingleFrame - good.
1046 *
1047 * SF_DL ESC offset optimization:
1048 *
1049 * When TX_DL is greater 8 but the message would still fit
1050 * into a 8 byte CAN frame, we can omit the offset.
1051 * This prevents a protocol caused length extension from
1052 * CAN_DL = 8 to CAN_DL = 12 due to the SF_SL ESC handling.
1053 */
1054 if (size <= CAN_MAX_DLEN - SF_PCI_SZ4 - ae)
1055 off = 0;
1056
1057 isotp_fill_dataframe(cf, so, ae, off);
1058
1059 /* place single frame N_PCI w/o length in appropriate index */
1060 cf->data[ae] = N_PCI_SF;
1061
1062 /* place SF_DL size value depending on the SF_DL ESC offset */
1063 if (off)
1064 cf->data[SF_PCI_SZ4 + ae] = size;
1065 else
1066 cf->data[ae] |= size;
1067
1068 /* set CF echo tag for isotp_rcv_echo() (SF-mode) */
1069 so->cfecho = *(u32 *)cf->data;
1070 } else {
1071 /* send first frame */
1072
1073 isotp_create_fframe(cf, so, ae);
1074
1075 if (isotp_bc_flags(so) == CAN_ISOTP_CF_BROADCAST) {
1076 /* set timer for FC-less operation (STmin = 0) */
1077 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
1078 so->tx_gap = ktime_set(0, so->force_tx_stmin);
1079 else
1080 so->tx_gap = ktime_set(0, so->frame_txtime);
1081
1082 /* disable wait for FCs due to activated block size */
1083 so->txfc.bs = 0;
1084
1085 /* set CF echo tag for isotp_rcv_echo() (CF-mode) */
1086 so->cfecho = *(u32 *)cf->data;
1087 } else {
1088 /* standard flow control check */
1089 so->tx.state = ISOTP_WAIT_FIRST_FC;
1090
1091 /* start timeout for FC */
1092 hrtimer_sec = ISOTP_FC_TIMEOUT;
1093
1094 /* no CF echo tag for isotp_rcv_echo() (FF-mode) */
1095 so->cfecho = 0;
1096 }
1097 }
1098
1099 hrtimer_start(&so->txtimer, ktime_set(hrtimer_sec, 0),
1100 HRTIMER_MODE_REL_SOFT);
1101
1102 /* send the first or only CAN frame */
1103 cf->flags = so->ll.tx_flags;
1104
1105 skb->dev = dev;
1106 skb->sk = sk;
1107 err = can_send(skb, 1);
1108 dev_put(dev);
1109 if (err) {
1110 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
1111 __func__, ERR_PTR(err));
1112
1113 /* no transmission -> no timeout monitoring */
1114 hrtimer_cancel(&so->txtimer);
1115
1116 /* reset consecutive frame echo tag */
1117 so->cfecho = 0;
1118
1119 goto err_out_drop;
1120 }
1121
1122 if (wait_tx_done) {
1123 /* wait for complete transmission of current pdu */
1124 err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
1125 if (err)
1126 goto err_event_drop;
1127
1128 err = sock_error(sk);
1129 if (err)
1130 return err;
1131 }
1132
1133 return size;
1134
1135 err_event_drop:
1136 /* got signal: force tx state machine to be idle */
1137 so->tx.state = ISOTP_IDLE;
1138 hrtimer_cancel(&so->txfrtimer);
1139 hrtimer_cancel(&so->txtimer);
1140 err_out_drop:
1141 /* drop this PDU and unlock a potential wait queue */
1142 so->tx.state = ISOTP_IDLE;
1143 wake_up_interruptible(&so->wait);
1144
1145 return err;
1146 }
1147
isotp_recvmsg(struct socket * sock,struct msghdr * msg,size_t size,int flags)1148 static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1149 int flags)
1150 {
1151 struct sock *sk = sock->sk;
1152 struct sk_buff *skb;
1153 struct isotp_sock *so = isotp_sk(sk);
1154 int ret = 0;
1155
1156 if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK | MSG_CMSG_COMPAT))
1157 return -EINVAL;
1158
1159 if (!so->bound)
1160 return -EADDRNOTAVAIL;
1161
1162 skb = skb_recv_datagram(sk, flags, &ret);
1163 if (!skb)
1164 return ret;
1165
1166 if (size < skb->len)
1167 msg->msg_flags |= MSG_TRUNC;
1168 else
1169 size = skb->len;
1170
1171 ret = memcpy_to_msg(msg, skb->data, size);
1172 if (ret < 0)
1173 goto out_err;
1174
1175 sock_recv_cmsgs(msg, sk, skb);
1176
1177 if (msg->msg_name) {
1178 __sockaddr_check_size(ISOTP_MIN_NAMELEN);
1179 msg->msg_namelen = ISOTP_MIN_NAMELEN;
1180 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1181 }
1182
1183 /* set length of return value */
1184 ret = (flags & MSG_TRUNC) ? skb->len : size;
1185
1186 out_err:
1187 skb_free_datagram(sk, skb);
1188
1189 return ret;
1190 }
1191
isotp_release(struct socket * sock)1192 static int isotp_release(struct socket *sock)
1193 {
1194 struct sock *sk = sock->sk;
1195 struct isotp_sock *so;
1196 struct net *net;
1197
1198 if (!sk)
1199 return 0;
1200
1201 so = isotp_sk(sk);
1202 net = sock_net(sk);
1203
1204 /* wait for complete transmission of current pdu */
1205 while (wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE) == 0 &&
1206 cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SHUTDOWN) != ISOTP_IDLE)
1207 ;
1208
1209 /* force state machines to be idle also when a signal occurred */
1210 so->tx.state = ISOTP_SHUTDOWN;
1211 so->rx.state = ISOTP_IDLE;
1212
1213 spin_lock(&isotp_notifier_lock);
1214 while (isotp_busy_notifier == so) {
1215 spin_unlock(&isotp_notifier_lock);
1216 schedule_timeout_uninterruptible(1);
1217 spin_lock(&isotp_notifier_lock);
1218 }
1219 list_del(&so->notifier);
1220 spin_unlock(&isotp_notifier_lock);
1221
1222 lock_sock(sk);
1223
1224 /* remove current filters & unregister */
1225 if (so->bound) {
1226 if (so->ifindex) {
1227 struct net_device *dev;
1228
1229 dev = dev_get_by_index(net, so->ifindex);
1230 if (dev) {
1231 if (isotp_register_rxid(so))
1232 can_rx_unregister(net, dev, so->rxid,
1233 SINGLE_MASK(so->rxid),
1234 isotp_rcv, sk);
1235
1236 can_rx_unregister(net, dev, so->txid,
1237 SINGLE_MASK(so->txid),
1238 isotp_rcv_echo, sk);
1239 dev_put(dev);
1240 synchronize_rcu();
1241 }
1242 }
1243 }
1244
1245 hrtimer_cancel(&so->txfrtimer);
1246 hrtimer_cancel(&so->txtimer);
1247 hrtimer_cancel(&so->rxtimer);
1248
1249 so->ifindex = 0;
1250 so->bound = 0;
1251
1252 sock_orphan(sk);
1253 sock->sk = NULL;
1254
1255 release_sock(sk);
1256 sock_prot_inuse_add(net, sk->sk_prot, -1);
1257 sock_put(sk);
1258
1259 return 0;
1260 }
1261
isotp_bind(struct socket * sock,struct sockaddr_unsized * uaddr,int len)1262 static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int len)
1263 {
1264 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1265 struct sock *sk = sock->sk;
1266 struct isotp_sock *so = isotp_sk(sk);
1267 struct net *net = sock_net(sk);
1268 int ifindex;
1269 struct net_device *dev;
1270 canid_t tx_id = addr->can_addr.tp.tx_id;
1271 canid_t rx_id = addr->can_addr.tp.rx_id;
1272 int err = 0;
1273 int notify_enetdown = 0;
1274
1275 if (len < ISOTP_MIN_NAMELEN)
1276 return -EINVAL;
1277
1278 if (addr->can_family != AF_CAN)
1279 return -EINVAL;
1280
1281 /* sanitize tx CAN identifier */
1282 if (tx_id & CAN_EFF_FLAG)
1283 tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1284 else
1285 tx_id &= CAN_SFF_MASK;
1286
1287 /* give feedback on wrong CAN-ID value */
1288 if (tx_id != addr->can_addr.tp.tx_id)
1289 return -EINVAL;
1290
1291 /* sanitize rx CAN identifier (if needed) */
1292 if (isotp_register_rxid(so)) {
1293 if (rx_id & CAN_EFF_FLAG)
1294 rx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1295 else
1296 rx_id &= CAN_SFF_MASK;
1297
1298 /* give feedback on wrong CAN-ID value */
1299 if (rx_id != addr->can_addr.tp.rx_id)
1300 return -EINVAL;
1301 }
1302
1303 if (!addr->can_ifindex)
1304 return -ENODEV;
1305
1306 lock_sock(sk);
1307
1308 if (so->bound) {
1309 err = -EINVAL;
1310 goto out;
1311 }
1312
1313 /* ensure different CAN IDs when the rx_id is to be registered */
1314 if (isotp_register_rxid(so) && rx_id == tx_id) {
1315 err = -EADDRNOTAVAIL;
1316 goto out;
1317 }
1318
1319 dev = dev_get_by_index(net, addr->can_ifindex);
1320 if (!dev) {
1321 err = -ENODEV;
1322 goto out;
1323 }
1324 if (dev->type != ARPHRD_CAN) {
1325 dev_put(dev);
1326 err = -ENODEV;
1327 goto out;
1328 }
1329 if (READ_ONCE(dev->mtu) < so->ll.mtu) {
1330 dev_put(dev);
1331 err = -EINVAL;
1332 goto out;
1333 }
1334 if (!(dev->flags & IFF_UP))
1335 notify_enetdown = 1;
1336
1337 ifindex = dev->ifindex;
1338
1339 if (isotp_register_rxid(so))
1340 can_rx_register(net, dev, rx_id, SINGLE_MASK(rx_id),
1341 isotp_rcv, sk, "isotp", sk);
1342
1343 /* no consecutive frame echo skb in flight */
1344 so->cfecho = 0;
1345
1346 /* register for echo skb's */
1347 can_rx_register(net, dev, tx_id, SINGLE_MASK(tx_id),
1348 isotp_rcv_echo, sk, "isotpe", sk);
1349
1350 dev_put(dev);
1351
1352 /* switch to new settings */
1353 so->ifindex = ifindex;
1354 so->rxid = rx_id;
1355 so->txid = tx_id;
1356 so->bound = 1;
1357
1358 out:
1359 release_sock(sk);
1360
1361 if (notify_enetdown) {
1362 sk->sk_err = ENETDOWN;
1363 if (!sock_flag(sk, SOCK_DEAD))
1364 sk_error_report(sk);
1365 }
1366
1367 return err;
1368 }
1369
isotp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)1370 static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1371 {
1372 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1373 struct sock *sk = sock->sk;
1374 struct isotp_sock *so = isotp_sk(sk);
1375
1376 if (peer)
1377 return -EOPNOTSUPP;
1378
1379 memset(addr, 0, ISOTP_MIN_NAMELEN);
1380 addr->can_family = AF_CAN;
1381 addr->can_ifindex = so->ifindex;
1382 addr->can_addr.tp.rx_id = so->rxid;
1383 addr->can_addr.tp.tx_id = so->txid;
1384
1385 return ISOTP_MIN_NAMELEN;
1386 }
1387
isotp_setsockopt_locked(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1388 static int isotp_setsockopt_locked(struct socket *sock, int level, int optname,
1389 sockptr_t optval, unsigned int optlen)
1390 {
1391 struct sock *sk = sock->sk;
1392 struct isotp_sock *so = isotp_sk(sk);
1393 int ret = 0;
1394
1395 if (so->bound)
1396 return -EISCONN;
1397
1398 switch (optname) {
1399 case CAN_ISOTP_OPTS:
1400 if (optlen != sizeof(struct can_isotp_options))
1401 return -EINVAL;
1402
1403 if (copy_from_sockptr(&so->opt, optval, optlen))
1404 return -EFAULT;
1405
1406 /* no separate rx_ext_address is given => use ext_address */
1407 if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))
1408 so->opt.rx_ext_address = so->opt.ext_address;
1409
1410 /* these broadcast flags are not allowed together */
1411 if (isotp_bc_flags(so) == ISOTP_ALL_BC_FLAGS) {
1412 /* CAN_ISOTP_SF_BROADCAST is prioritized */
1413 so->opt.flags &= ~CAN_ISOTP_CF_BROADCAST;
1414
1415 /* give user feedback on wrong config attempt */
1416 ret = -EINVAL;
1417 }
1418
1419 /* check for frame_txtime changes (0 => no changes) */
1420 if (so->opt.frame_txtime) {
1421 if (so->opt.frame_txtime == CAN_ISOTP_FRAME_TXTIME_ZERO)
1422 so->frame_txtime = 0;
1423 else
1424 so->frame_txtime = so->opt.frame_txtime;
1425 }
1426 break;
1427
1428 case CAN_ISOTP_RECV_FC:
1429 if (optlen != sizeof(struct can_isotp_fc_options))
1430 return -EINVAL;
1431
1432 if (copy_from_sockptr(&so->rxfc, optval, optlen))
1433 return -EFAULT;
1434 break;
1435
1436 case CAN_ISOTP_TX_STMIN:
1437 if (optlen != sizeof(u32))
1438 return -EINVAL;
1439
1440 if (copy_from_sockptr(&so->force_tx_stmin, optval, optlen))
1441 return -EFAULT;
1442 break;
1443
1444 case CAN_ISOTP_RX_STMIN:
1445 if (optlen != sizeof(u32))
1446 return -EINVAL;
1447
1448 if (copy_from_sockptr(&so->force_rx_stmin, optval, optlen))
1449 return -EFAULT;
1450 break;
1451
1452 case CAN_ISOTP_LL_OPTS:
1453 if (optlen == sizeof(struct can_isotp_ll_options)) {
1454 struct can_isotp_ll_options ll;
1455
1456 if (copy_from_sockptr(&ll, optval, optlen))
1457 return -EFAULT;
1458
1459 /* check for correct ISO 11898-1 DLC data length */
1460 if (ll.tx_dl != padlen(ll.tx_dl))
1461 return -EINVAL;
1462
1463 if (ll.mtu != CAN_MTU && ll.mtu != CANFD_MTU)
1464 return -EINVAL;
1465
1466 if (ll.mtu == CAN_MTU &&
1467 (ll.tx_dl > CAN_MAX_DLEN || ll.tx_flags != 0))
1468 return -EINVAL;
1469
1470 memcpy(&so->ll, &ll, sizeof(ll));
1471
1472 /* set ll_dl for tx path to similar place as for rx */
1473 so->tx.ll_dl = ll.tx_dl;
1474 } else {
1475 return -EINVAL;
1476 }
1477 break;
1478
1479 default:
1480 ret = -ENOPROTOOPT;
1481 }
1482
1483 return ret;
1484 }
1485
isotp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1486 static int isotp_setsockopt(struct socket *sock, int level, int optname,
1487 sockptr_t optval, unsigned int optlen)
1488
1489 {
1490 struct sock *sk = sock->sk;
1491 int ret;
1492
1493 if (level != SOL_CAN_ISOTP)
1494 return -EINVAL;
1495
1496 lock_sock(sk);
1497 ret = isotp_setsockopt_locked(sock, level, optname, optval, optlen);
1498 release_sock(sk);
1499 return ret;
1500 }
1501
isotp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1502 static int isotp_getsockopt(struct socket *sock, int level, int optname,
1503 char __user *optval, int __user *optlen)
1504 {
1505 struct sock *sk = sock->sk;
1506 struct isotp_sock *so = isotp_sk(sk);
1507 int len;
1508 void *val;
1509
1510 if (level != SOL_CAN_ISOTP)
1511 return -EINVAL;
1512 if (get_user(len, optlen))
1513 return -EFAULT;
1514 if (len < 0)
1515 return -EINVAL;
1516
1517 switch (optname) {
1518 case CAN_ISOTP_OPTS:
1519 len = min_t(int, len, sizeof(struct can_isotp_options));
1520 val = &so->opt;
1521 break;
1522
1523 case CAN_ISOTP_RECV_FC:
1524 len = min_t(int, len, sizeof(struct can_isotp_fc_options));
1525 val = &so->rxfc;
1526 break;
1527
1528 case CAN_ISOTP_TX_STMIN:
1529 len = min_t(int, len, sizeof(u32));
1530 val = &so->force_tx_stmin;
1531 break;
1532
1533 case CAN_ISOTP_RX_STMIN:
1534 len = min_t(int, len, sizeof(u32));
1535 val = &so->force_rx_stmin;
1536 break;
1537
1538 case CAN_ISOTP_LL_OPTS:
1539 len = min_t(int, len, sizeof(struct can_isotp_ll_options));
1540 val = &so->ll;
1541 break;
1542
1543 default:
1544 return -ENOPROTOOPT;
1545 }
1546
1547 if (put_user(len, optlen))
1548 return -EFAULT;
1549 if (copy_to_user(optval, val, len))
1550 return -EFAULT;
1551 return 0;
1552 }
1553
isotp_notify(struct isotp_sock * so,unsigned long msg,struct net_device * dev)1554 static void isotp_notify(struct isotp_sock *so, unsigned long msg,
1555 struct net_device *dev)
1556 {
1557 struct sock *sk = &so->sk;
1558
1559 if (!net_eq(dev_net(dev), sock_net(sk)))
1560 return;
1561
1562 if (so->ifindex != dev->ifindex)
1563 return;
1564
1565 switch (msg) {
1566 case NETDEV_UNREGISTER:
1567 lock_sock(sk);
1568 /* remove current filters & unregister */
1569 if (so->bound) {
1570 if (isotp_register_rxid(so))
1571 can_rx_unregister(dev_net(dev), dev, so->rxid,
1572 SINGLE_MASK(so->rxid),
1573 isotp_rcv, sk);
1574
1575 can_rx_unregister(dev_net(dev), dev, so->txid,
1576 SINGLE_MASK(so->txid),
1577 isotp_rcv_echo, sk);
1578 }
1579
1580 so->ifindex = 0;
1581 so->bound = 0;
1582 release_sock(sk);
1583
1584 sk->sk_err = ENODEV;
1585 if (!sock_flag(sk, SOCK_DEAD))
1586 sk_error_report(sk);
1587 break;
1588
1589 case NETDEV_DOWN:
1590 sk->sk_err = ENETDOWN;
1591 if (!sock_flag(sk, SOCK_DEAD))
1592 sk_error_report(sk);
1593 break;
1594 }
1595 }
1596
isotp_notifier(struct notifier_block * nb,unsigned long msg,void * ptr)1597 static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
1598 void *ptr)
1599 {
1600 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1601
1602 if (dev->type != ARPHRD_CAN)
1603 return NOTIFY_DONE;
1604 if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1605 return NOTIFY_DONE;
1606 if (unlikely(isotp_busy_notifier)) /* Check for reentrant bug. */
1607 return NOTIFY_DONE;
1608
1609 spin_lock(&isotp_notifier_lock);
1610 list_for_each_entry(isotp_busy_notifier, &isotp_notifier_list, notifier) {
1611 spin_unlock(&isotp_notifier_lock);
1612 isotp_notify(isotp_busy_notifier, msg, dev);
1613 spin_lock(&isotp_notifier_lock);
1614 }
1615 isotp_busy_notifier = NULL;
1616 spin_unlock(&isotp_notifier_lock);
1617 return NOTIFY_DONE;
1618 }
1619
isotp_sock_destruct(struct sock * sk)1620 static void isotp_sock_destruct(struct sock *sk)
1621 {
1622 struct isotp_sock *so = isotp_sk(sk);
1623
1624 /* do the standard CAN sock destruct work */
1625 can_sock_destruct(sk);
1626
1627 /* free potential extended PDU buffers */
1628 if (so->rx.buf != so->rx.sbuf)
1629 kfree(so->rx.buf);
1630
1631 if (so->tx.buf != so->tx.sbuf)
1632 kfree(so->tx.buf);
1633 }
1634
isotp_init(struct sock * sk)1635 static int isotp_init(struct sock *sk)
1636 {
1637 struct isotp_sock *so = isotp_sk(sk);
1638
1639 so->ifindex = 0;
1640 so->bound = 0;
1641
1642 so->opt.flags = CAN_ISOTP_DEFAULT_FLAGS;
1643 so->opt.ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1644 so->opt.rx_ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1645 so->opt.rxpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1646 so->opt.txpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1647 so->opt.frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1648 so->frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1649 so->rxfc.bs = CAN_ISOTP_DEFAULT_RECV_BS;
1650 so->rxfc.stmin = CAN_ISOTP_DEFAULT_RECV_STMIN;
1651 so->rxfc.wftmax = CAN_ISOTP_DEFAULT_RECV_WFTMAX;
1652 so->ll.mtu = CAN_ISOTP_DEFAULT_LL_MTU;
1653 so->ll.tx_dl = CAN_ISOTP_DEFAULT_LL_TX_DL;
1654 so->ll.tx_flags = CAN_ISOTP_DEFAULT_LL_TX_FLAGS;
1655
1656 /* set ll_dl for tx path to similar place as for rx */
1657 so->tx.ll_dl = so->ll.tx_dl;
1658
1659 so->rx.state = ISOTP_IDLE;
1660 so->tx.state = ISOTP_IDLE;
1661
1662 so->rx.buf = so->rx.sbuf;
1663 so->tx.buf = so->tx.sbuf;
1664 so->rx.buflen = ARRAY_SIZE(so->rx.sbuf);
1665 so->tx.buflen = ARRAY_SIZE(so->tx.sbuf);
1666
1667 hrtimer_setup(&so->rxtimer, isotp_rx_timer_handler, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1668 hrtimer_setup(&so->txtimer, isotp_tx_timer_handler, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1669 hrtimer_setup(&so->txfrtimer, isotp_txfr_timer_handler, CLOCK_MONOTONIC,
1670 HRTIMER_MODE_REL_SOFT);
1671
1672 init_waitqueue_head(&so->wait);
1673 spin_lock_init(&so->rx_lock);
1674
1675 spin_lock(&isotp_notifier_lock);
1676 list_add_tail(&so->notifier, &isotp_notifier_list);
1677 spin_unlock(&isotp_notifier_lock);
1678
1679 /* re-assign default can_sock_destruct() reference */
1680 sk->sk_destruct = isotp_sock_destruct;
1681
1682 return 0;
1683 }
1684
isotp_poll(struct file * file,struct socket * sock,poll_table * wait)1685 static __poll_t isotp_poll(struct file *file, struct socket *sock, poll_table *wait)
1686 {
1687 struct sock *sk = sock->sk;
1688 struct isotp_sock *so = isotp_sk(sk);
1689
1690 __poll_t mask = datagram_poll(file, sock, wait);
1691 poll_wait(file, &so->wait, wait);
1692
1693 /* Check for false positives due to TX state */
1694 if ((mask & EPOLLWRNORM) && (so->tx.state != ISOTP_IDLE))
1695 mask &= ~(EPOLLOUT | EPOLLWRNORM);
1696
1697 return mask;
1698 }
1699
isotp_sock_no_ioctlcmd(struct socket * sock,unsigned int cmd,unsigned long arg)1700 static int isotp_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
1701 unsigned long arg)
1702 {
1703 /* no ioctls for socket layer -> hand it down to NIC layer */
1704 return -ENOIOCTLCMD;
1705 }
1706
1707 static const struct proto_ops isotp_ops = {
1708 .family = PF_CAN,
1709 .release = isotp_release,
1710 .bind = isotp_bind,
1711 .connect = sock_no_connect,
1712 .socketpair = sock_no_socketpair,
1713 .accept = sock_no_accept,
1714 .getname = isotp_getname,
1715 .poll = isotp_poll,
1716 .ioctl = isotp_sock_no_ioctlcmd,
1717 .gettstamp = sock_gettstamp,
1718 .listen = sock_no_listen,
1719 .shutdown = sock_no_shutdown,
1720 .setsockopt = isotp_setsockopt,
1721 .getsockopt = isotp_getsockopt,
1722 .sendmsg = isotp_sendmsg,
1723 .recvmsg = isotp_recvmsg,
1724 .mmap = sock_no_mmap,
1725 };
1726
1727 static struct proto isotp_proto __read_mostly = {
1728 .name = "CAN_ISOTP",
1729 .owner = THIS_MODULE,
1730 .obj_size = sizeof(struct isotp_sock),
1731 .init = isotp_init,
1732 };
1733
1734 static const struct can_proto isotp_can_proto = {
1735 .type = SOCK_DGRAM,
1736 .protocol = CAN_ISOTP,
1737 .ops = &isotp_ops,
1738 .prot = &isotp_proto,
1739 };
1740
1741 static struct notifier_block canisotp_notifier = {
1742 .notifier_call = isotp_notifier
1743 };
1744
isotp_module_init(void)1745 static __init int isotp_module_init(void)
1746 {
1747 int err;
1748
1749 max_pdu_size = max_t(unsigned int, max_pdu_size, MAX_12BIT_PDU_SIZE);
1750 max_pdu_size = min_t(unsigned int, max_pdu_size, MAX_PDU_SIZE);
1751
1752 pr_info("can: isotp protocol (max_pdu_size %d)\n", max_pdu_size);
1753
1754 err = can_proto_register(&isotp_can_proto);
1755 if (err < 0)
1756 pr_err("can: registration of isotp protocol failed %pe\n", ERR_PTR(err));
1757 else
1758 register_netdevice_notifier(&canisotp_notifier);
1759
1760 return err;
1761 }
1762
isotp_module_exit(void)1763 static __exit void isotp_module_exit(void)
1764 {
1765 can_proto_unregister(&isotp_can_proto);
1766 unregister_netdevice_notifier(&canisotp_notifier);
1767 }
1768
1769 module_init(isotp_module_init);
1770 module_exit(isotp_module_exit);
1771