1
2
3
4
5
6
7
8
9
10
11
12#define pr_fmt(fmt) "IPv4: " fmt
13
14#include <linux/capability.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/types.h>
18#include <asm/uaccess.h>
19#include <asm/unaligned.h>
20#include <linux/skbuff.h>
21#include <linux/ip.h>
22#include <linux/icmp.h>
23#include <linux/netdevice.h>
24#include <linux/rtnetlink.h>
25#include <net/sock.h>
26#include <net/ip.h>
27#include <net/icmp.h>
28#include <net/route.h>
29#include <net/cipso_ipv4.h>
30#include <net/ip_fib.h>
31
32
33
34
35
36
37
38
39
40
41
42
43void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
44 __be32 daddr, struct rtable *rt, int is_frag)
45{
46 unsigned char *iph = skb_network_header(skb);
47
48 memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
49 memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
50 opt = &(IPCB(skb)->opt);
51
52 if (opt->srr)
53 memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
54
55 if (!is_frag) {
56 if (opt->rr_needaddr)
57 ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, skb, rt);
58 if (opt->ts_needaddr)
59 ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt);
60 if (opt->ts_needtime) {
61 struct timespec tv;
62 __be32 midtime;
63 getnstimeofday(&tv);
64 midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC);
65 memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
66 }
67 return;
68 }
69 if (opt->rr) {
70 memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
71 opt->rr = 0;
72 opt->rr_needaddr = 0;
73 }
74 if (opt->ts) {
75 memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
76 opt->ts = 0;
77 opt->ts_needaddr = opt->ts_needtime = 0;
78 }
79}
80
81
82
83
84
85
86
87
88
89
90int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb)
91{
92 const struct ip_options *sopt;
93 unsigned char *sptr, *dptr;
94 int soffset, doffset;
95 int optlen;
96
97 memset(dopt, 0, sizeof(struct ip_options));
98
99 sopt = &(IPCB(skb)->opt);
100
101 if (sopt->optlen == 0)
102 return 0;
103
104 sptr = skb_network_header(skb);
105 dptr = dopt->__data;
106
107 if (sopt->rr) {
108 optlen = sptr[sopt->rr+1];
109 soffset = sptr[sopt->rr+2];
110 dopt->rr = dopt->optlen + sizeof(struct iphdr);
111 memcpy(dptr, sptr+sopt->rr, optlen);
112 if (sopt->rr_needaddr && soffset <= optlen) {
113 if (soffset + 3 > optlen)
114 return -EINVAL;
115 dptr[2] = soffset + 4;
116 dopt->rr_needaddr = 1;
117 }
118 dptr += optlen;
119 dopt->optlen += optlen;
120 }
121 if (sopt->ts) {
122 optlen = sptr[sopt->ts+1];
123 soffset = sptr[sopt->ts+2];
124 dopt->ts = dopt->optlen + sizeof(struct iphdr);
125 memcpy(dptr, sptr+sopt->ts, optlen);
126 if (soffset <= optlen) {
127 if (sopt->ts_needaddr) {
128 if (soffset + 3 > optlen)
129 return -EINVAL;
130 dopt->ts_needaddr = 1;
131 soffset += 4;
132 }
133 if (sopt->ts_needtime) {
134 if (soffset + 3 > optlen)
135 return -EINVAL;
136 if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
137 dopt->ts_needtime = 1;
138 soffset += 4;
139 } else {
140 dopt->ts_needtime = 0;
141
142 if (soffset + 7 <= optlen) {
143 __be32 addr;
144
145 memcpy(&addr, dptr+soffset-1, 4);
146 if (inet_addr_type(dev_net(skb_dst(skb)->dev), addr) != RTN_UNICAST) {
147 dopt->ts_needtime = 1;
148 soffset += 8;
149 }
150 }
151 }
152 }
153 dptr[2] = soffset;
154 }
155 dptr += optlen;
156 dopt->optlen += optlen;
157 }
158 if (sopt->srr) {
159 unsigned char *start = sptr+sopt->srr;
160 __be32 faddr;
161
162 optlen = start[1];
163 soffset = start[2];
164 doffset = 0;
165 if (soffset > optlen)
166 soffset = optlen + 1;
167 soffset -= 4;
168 if (soffset > 3) {
169 memcpy(&faddr, &start[soffset-1], 4);
170 for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4)
171 memcpy(&dptr[doffset-1], &start[soffset-1], 4);
172
173
174
175 if (memcmp(&ip_hdr(skb)->saddr,
176 &start[soffset + 3], 4) == 0)
177 doffset -= 4;
178 }
179 if (doffset > 3) {
180 __be32 daddr = fib_compute_spec_dst(skb);
181
182 memcpy(&start[doffset-1], &daddr, 4);
183 dopt->faddr = faddr;
184 dptr[0] = start[0];
185 dptr[1] = doffset+3;
186 dptr[2] = 4;
187 dptr += doffset+3;
188 dopt->srr = dopt->optlen + sizeof(struct iphdr);
189 dopt->optlen += doffset+3;
190 dopt->is_strictroute = sopt->is_strictroute;
191 }
192 }
193 if (sopt->cipso) {
194 optlen = sptr[sopt->cipso+1];
195 dopt->cipso = dopt->optlen+sizeof(struct iphdr);
196 memcpy(dptr, sptr+sopt->cipso, optlen);
197 dptr += optlen;
198 dopt->optlen += optlen;
199 }
200 while (dopt->optlen & 3) {
201 *dptr++ = IPOPT_END;
202 dopt->optlen++;
203 }
204 return 0;
205}
206
207
208
209
210
211
212
213void ip_options_fragment(struct sk_buff *skb)
214{
215 unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr);
216 struct ip_options *opt = &(IPCB(skb)->opt);
217 int l = opt->optlen;
218 int optlen;
219
220 while (l > 0) {
221 switch (*optptr) {
222 case IPOPT_END:
223 return;
224 case IPOPT_NOOP:
225 l--;
226 optptr++;
227 continue;
228 }
229 optlen = optptr[1];
230 if (optlen<2 || optlen>l)
231 return;
232 if (!IPOPT_COPIED(*optptr))
233 memset(optptr, IPOPT_NOOP, optlen);
234 l -= optlen;
235 optptr += optlen;
236 }
237 opt->ts = 0;
238 opt->rr = 0;
239 opt->rr_needaddr = 0;
240 opt->ts_needaddr = 0;
241 opt->ts_needtime = 0;
242}
243
244
245
246
247static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb)
248{
249 if (*spec_dst == htonl(INADDR_ANY))
250 *spec_dst = fib_compute_spec_dst(skb);
251}
252
253
254
255
256
257
258
259int ip_options_compile(struct net *net,
260 struct ip_options *opt, struct sk_buff *skb)
261{
262 __be32 spec_dst = htonl(INADDR_ANY);
263 unsigned char *pp_ptr = NULL;
264 struct rtable *rt = NULL;
265 unsigned char *optptr;
266 unsigned char *iph;
267 int optlen, l;
268
269 if (skb != NULL) {
270 rt = skb_rtable(skb);
271 optptr = (unsigned char *)&(ip_hdr(skb)[1]);
272 } else
273 optptr = opt->__data;
274 iph = optptr - sizeof(struct iphdr);
275
276 for (l = opt->optlen; l > 0; ) {
277 switch (*optptr) {
278 case IPOPT_END:
279 for (optptr++, l--; l>0; optptr++, l--) {
280 if (*optptr != IPOPT_END) {
281 *optptr = IPOPT_END;
282 opt->is_changed = 1;
283 }
284 }
285 goto eol;
286 case IPOPT_NOOP:
287 l--;
288 optptr++;
289 continue;
290 }
291 optlen = optptr[1];
292 if (optlen<2 || optlen>l) {
293 pp_ptr = optptr;
294 goto error;
295 }
296 switch (*optptr) {
297 case IPOPT_SSRR:
298 case IPOPT_LSRR:
299 if (optlen < 3) {
300 pp_ptr = optptr + 1;
301 goto error;
302 }
303 if (optptr[2] < 4) {
304 pp_ptr = optptr + 2;
305 goto error;
306 }
307
308 if (opt->srr) {
309 pp_ptr = optptr;
310 goto error;
311 }
312 if (!skb) {
313 if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
314 pp_ptr = optptr + 1;
315 goto error;
316 }
317 memcpy(&opt->faddr, &optptr[3], 4);
318 if (optlen > 7)
319 memmove(&optptr[3], &optptr[7], optlen-7);
320 }
321 opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
322 opt->srr = optptr - iph;
323 break;
324 case IPOPT_RR:
325 if (opt->rr) {
326 pp_ptr = optptr;
327 goto error;
328 }
329 if (optlen < 3) {
330 pp_ptr = optptr + 1;
331 goto error;
332 }
333 if (optptr[2] < 4) {
334 pp_ptr = optptr + 2;
335 goto error;
336 }
337 if (optptr[2] <= optlen) {
338 if (optptr[2]+3 > optlen) {
339 pp_ptr = optptr + 2;
340 goto error;
341 }
342 if (rt) {
343 spec_dst_fill(&spec_dst, skb);
344 memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
345 opt->is_changed = 1;
346 }
347 optptr[2] += 4;
348 opt->rr_needaddr = 1;
349 }
350 opt->rr = optptr - iph;
351 break;
352 case IPOPT_TIMESTAMP:
353 if (opt->ts) {
354 pp_ptr = optptr;
355 goto error;
356 }
357 if (optlen < 4) {
358 pp_ptr = optptr + 1;
359 goto error;
360 }
361 if (optptr[2] < 5) {
362 pp_ptr = optptr + 2;
363 goto error;
364 }
365 if (optptr[2] <= optlen) {
366 unsigned char *timeptr = NULL;
367 if (optptr[2]+3 > optptr[1]) {
368 pp_ptr = optptr + 2;
369 goto error;
370 }
371 switch (optptr[3]&0xF) {
372 case IPOPT_TS_TSONLY:
373 if (skb)
374 timeptr = &optptr[optptr[2]-1];
375 opt->ts_needtime = 1;
376 optptr[2] += 4;
377 break;
378 case IPOPT_TS_TSANDADDR:
379 if (optptr[2]+7 > optptr[1]) {
380 pp_ptr = optptr + 2;
381 goto error;
382 }
383 if (rt) {
384 spec_dst_fill(&spec_dst, skb);
385 memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
386 timeptr = &optptr[optptr[2]+3];
387 }
388 opt->ts_needaddr = 1;
389 opt->ts_needtime = 1;
390 optptr[2] += 8;
391 break;
392 case IPOPT_TS_PRESPEC:
393 if (optptr[2]+7 > optptr[1]) {
394 pp_ptr = optptr + 2;
395 goto error;
396 }
397 {
398 __be32 addr;
399 memcpy(&addr, &optptr[optptr[2]-1], 4);
400 if (inet_addr_type(net, addr) == RTN_UNICAST)
401 break;
402 if (skb)
403 timeptr = &optptr[optptr[2]+3];
404 }
405 opt->ts_needtime = 1;
406 optptr[2] += 8;
407 break;
408 default:
409 if (!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) {
410 pp_ptr = optptr + 3;
411 goto error;
412 }
413 break;
414 }
415 if (timeptr) {
416 struct timespec tv;
417 u32 midtime;
418 getnstimeofday(&tv);
419 midtime = (tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC;
420 put_unaligned_be32(midtime, timeptr);
421 opt->is_changed = 1;
422 }
423 } else if ((optptr[3]&0xF) != IPOPT_TS_PRESPEC) {
424 unsigned int overflow = optptr[3]>>4;
425 if (overflow == 15) {
426 pp_ptr = optptr + 3;
427 goto error;
428 }
429 if (skb) {
430 optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
431 opt->is_changed = 1;
432 }
433 }
434 opt->ts = optptr - iph;
435 break;
436 case IPOPT_RA:
437 if (optlen < 4) {
438 pp_ptr = optptr + 1;
439 goto error;
440 }
441 if (optptr[2] == 0 && optptr[3] == 0)
442 opt->router_alert = optptr - iph;
443 break;
444 case IPOPT_CIPSO:
445 if ((!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) || opt->cipso) {
446 pp_ptr = optptr;
447 goto error;
448 }
449 opt->cipso = optptr - iph;
450 if (cipso_v4_validate(skb, &optptr)) {
451 pp_ptr = optptr;
452 goto error;
453 }
454 break;
455 case IPOPT_SEC:
456 case IPOPT_SID:
457 default:
458 if (!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) {
459 pp_ptr = optptr;
460 goto error;
461 }
462 break;
463 }
464 l -= optlen;
465 optptr += optlen;
466 }
467
468eol:
469 if (!pp_ptr)
470 return 0;
471
472error:
473 if (skb) {
474 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
475 }
476 return -EINVAL;
477}
478EXPORT_SYMBOL(ip_options_compile);
479
480
481
482
483
484void ip_options_undo(struct ip_options *opt)
485{
486 if (opt->srr) {
487 unsigned char *optptr = opt->__data+opt->srr-sizeof(struct iphdr);
488 memmove(optptr+7, optptr+3, optptr[1]-7);
489 memcpy(optptr+3, &opt->faddr, 4);
490 }
491 if (opt->rr_needaddr) {
492 unsigned char *optptr = opt->__data+opt->rr-sizeof(struct iphdr);
493 optptr[2] -= 4;
494 memset(&optptr[optptr[2]-1], 0, 4);
495 }
496 if (opt->ts) {
497 unsigned char *optptr = opt->__data+opt->ts-sizeof(struct iphdr);
498 if (opt->ts_needtime) {
499 optptr[2] -= 4;
500 memset(&optptr[optptr[2]-1], 0, 4);
501 if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
502 optptr[2] -= 4;
503 }
504 if (opt->ts_needaddr) {
505 optptr[2] -= 4;
506 memset(&optptr[optptr[2]-1], 0, 4);
507 }
508 }
509}
510
511static struct ip_options_rcu *ip_options_get_alloc(const int optlen)
512{
513 return kzalloc(sizeof(struct ip_options_rcu) + ((optlen + 3) & ~3),
514 GFP_KERNEL);
515}
516
517static int ip_options_get_finish(struct net *net, struct ip_options_rcu **optp,
518 struct ip_options_rcu *opt, int optlen)
519{
520 while (optlen & 3)
521 opt->opt.__data[optlen++] = IPOPT_END;
522 opt->opt.optlen = optlen;
523 if (optlen && ip_options_compile(net, &opt->opt, NULL)) {
524 kfree(opt);
525 return -EINVAL;
526 }
527 kfree(*optp);
528 *optp = opt;
529 return 0;
530}
531
532int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
533 unsigned char __user *data, int optlen)
534{
535 struct ip_options_rcu *opt = ip_options_get_alloc(optlen);
536
537 if (!opt)
538 return -ENOMEM;
539 if (optlen && copy_from_user(opt->opt.__data, data, optlen)) {
540 kfree(opt);
541 return -EFAULT;
542 }
543 return ip_options_get_finish(net, optp, opt, optlen);
544}
545
546int ip_options_get(struct net *net, struct ip_options_rcu **optp,
547 unsigned char *data, int optlen)
548{
549 struct ip_options_rcu *opt = ip_options_get_alloc(optlen);
550
551 if (!opt)
552 return -ENOMEM;
553 if (optlen)
554 memcpy(opt->opt.__data, data, optlen);
555 return ip_options_get_finish(net, optp, opt, optlen);
556}
557
558void ip_forward_options(struct sk_buff *skb)
559{
560 struct ip_options *opt = &(IPCB(skb)->opt);
561 unsigned char *optptr;
562 struct rtable *rt = skb_rtable(skb);
563 unsigned char *raw = skb_network_header(skb);
564
565 if (opt->rr_needaddr) {
566 optptr = (unsigned char *)raw + opt->rr;
567 ip_rt_get_source(&optptr[optptr[2]-5], skb, rt);
568 opt->is_changed = 1;
569 }
570 if (opt->srr_is_hit) {
571 int srrptr, srrspace;
572
573 optptr = raw + opt->srr;
574
575 for ( srrptr=optptr[2], srrspace = optptr[1];
576 srrptr <= srrspace;
577 srrptr += 4
578 ) {
579 if (srrptr + 3 > srrspace)
580 break;
581 if (memcmp(&opt->nexthop, &optptr[srrptr-1], 4) == 0)
582 break;
583 }
584 if (srrptr + 3 <= srrspace) {
585 opt->is_changed = 1;
586 ip_hdr(skb)->daddr = opt->nexthop;
587 ip_rt_get_source(&optptr[srrptr-1], skb, rt);
588 optptr[2] = srrptr+4;
589 } else {
590 net_crit_ratelimited("%s(): Argh! Destination lost!\n",
591 __func__);
592 }
593 if (opt->ts_needaddr) {
594 optptr = raw + opt->ts;
595 ip_rt_get_source(&optptr[optptr[2]-9], skb, rt);
596 opt->is_changed = 1;
597 }
598 }
599 if (opt->is_changed) {
600 opt->is_changed = 0;
601 ip_send_check(ip_hdr(skb));
602 }
603}
604
605int ip_options_rcv_srr(struct sk_buff *skb)
606{
607 struct ip_options *opt = &(IPCB(skb)->opt);
608 int srrspace, srrptr;
609 __be32 nexthop;
610 struct iphdr *iph = ip_hdr(skb);
611 unsigned char *optptr = skb_network_header(skb) + opt->srr;
612 struct rtable *rt = skb_rtable(skb);
613 struct rtable *rt2;
614 unsigned long orefdst;
615 int err;
616
617 if (!rt)
618 return 0;
619
620 if (skb->pkt_type != PACKET_HOST)
621 return -EINVAL;
622 if (rt->rt_type == RTN_UNICAST) {
623 if (!opt->is_strictroute)
624 return 0;
625 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
626 return -EINVAL;
627 }
628 if (rt->rt_type != RTN_LOCAL)
629 return -EINVAL;
630
631 for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
632 if (srrptr + 3 > srrspace) {
633 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
634 return -EINVAL;
635 }
636 memcpy(&nexthop, &optptr[srrptr-1], 4);
637
638 orefdst = skb->_skb_refdst;
639 skb_dst_set(skb, NULL);
640 err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
641 rt2 = skb_rtable(skb);
642 if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
643 skb_dst_drop(skb);
644 skb->_skb_refdst = orefdst;
645 return -EINVAL;
646 }
647 refdst_drop(orefdst);
648 if (rt2->rt_type != RTN_LOCAL)
649 break;
650
651 iph->daddr = nexthop;
652 opt->is_changed = 1;
653 }
654 if (srrptr <= srrspace) {
655 opt->srr_is_hit = 1;
656 opt->nexthop = nexthop;
657 opt->is_changed = 1;
658 }
659 return 0;
660}
661EXPORT_SYMBOL(ip_options_rcv_srr);
662
