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