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