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drm/tests: hdmi: Fix memory leaks in drm_display_mode_from_cea_vic()
[drm/drm-misc.git] / net / core / lwt_bpf.c
blob1a14f915b7a448cfacaea15bdeb886695ad10921
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
3 */
4
5 #include <linux/filter.h>
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/skbuff.h>
9 #include <linux/types.h>
10 #include <linux/bpf.h>
11 #include <net/lwtunnel.h>
12 #include <net/gre.h>
13 #include <net/ip6_route.h>
14 #include <net/ipv6_stubs.h>
15 #include <net/inet_dscp.h>
16
17 struct bpf_lwt_prog {
18 struct bpf_prog *prog;
19 char *name;
20 };
21
22 struct bpf_lwt {
23 struct bpf_lwt_prog in;
24 struct bpf_lwt_prog out;
25 struct bpf_lwt_prog xmit;
26 int family;
27 };
28
29 #define MAX_PROG_NAME 256
30
31 static inline struct bpf_lwt *bpf_lwt_lwtunnel(struct lwtunnel_state *lwt)
32 {
33 return (struct bpf_lwt *)lwt->data;
34 }
35
36 #define NO_REDIRECT false
37 #define CAN_REDIRECT true
38
39 static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
40 struct dst_entry *dst, bool can_redirect)
41 {
42 struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
43 int ret;
44
45 /* Disabling BH is needed to protect per-CPU bpf_redirect_info between
46 * BPF prog and skb_do_redirect().
47 */
48 local_bh_disable();
49 bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
50 bpf_compute_data_pointers(skb);
51 ret = bpf_prog_run_save_cb(lwt->prog, skb);
52
53 switch (ret) {
54 case BPF_OK:
55 case BPF_LWT_REROUTE:
56 break;
57
58 case BPF_REDIRECT:
59 if (unlikely(!can_redirect)) {
60 pr_warn_once("Illegal redirect return code in prog %s\n",
61 lwt->name ? : "<unknown>");
62 ret = BPF_OK;
63 } else {
64 skb_reset_mac_header(skb);
65 skb_do_redirect(skb);
66 ret = BPF_REDIRECT;
67 }
68 break;
69
70 case BPF_DROP:
71 kfree_skb(skb);
72 ret = -EPERM;
73 break;
74
75 default:
76 pr_warn_once("bpf-lwt: Illegal return value %u, expect packet loss\n", ret);
77 kfree_skb(skb);
78 ret = -EINVAL;
79 break;
80 }
81
82 bpf_net_ctx_clear(bpf_net_ctx);
83 local_bh_enable();
84
85 return ret;
86 }
87
88 static int bpf_lwt_input_reroute(struct sk_buff *skb)
89 {
90 int err = -EINVAL;
91
92 if (skb->protocol == htons(ETH_P_IP)) {
93 struct net_device *dev = skb_dst(skb)->dev;
94 struct iphdr *iph = ip_hdr(skb);
95
96 dev_hold(dev);
97 skb_dst_drop(skb);
98 err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
99 iph->tos, dev);
100 dev_put(dev);
101 } else if (skb->protocol == htons(ETH_P_IPV6)) {
102 skb_dst_drop(skb);
103 err = ipv6_stub->ipv6_route_input(skb);
104 } else {
105 err = -EAFNOSUPPORT;
106 }
107
108 if (err)
109 goto err;
110 return dst_input(skb);
111
112 err:
113 kfree_skb(skb);
114 return err;
115 }
116
117 static int bpf_input(struct sk_buff *skb)
118 {
119 struct dst_entry *dst = skb_dst(skb);
120 struct bpf_lwt *bpf;
121 int ret;
122
123 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
124 if (bpf->in.prog) {
125 ret = run_lwt_bpf(skb, &bpf->in, dst, NO_REDIRECT);
126 if (ret < 0)
127 return ret;
128 if (ret == BPF_LWT_REROUTE)
129 return bpf_lwt_input_reroute(skb);
130 }
131
132 if (unlikely(!dst->lwtstate->orig_input)) {
133 kfree_skb(skb);
134 return -EINVAL;
135 }
136
137 return dst->lwtstate->orig_input(skb);
138 }
139
140 static int bpf_output(struct net *net, struct sock *sk, struct sk_buff *skb)
141 {
142 struct dst_entry *dst = skb_dst(skb);
143 struct bpf_lwt *bpf;
144 int ret;
145
146 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
147 if (bpf->out.prog) {
148 ret = run_lwt_bpf(skb, &bpf->out, dst, NO_REDIRECT);
149 if (ret < 0)
150 return ret;
151 }
152
153 if (unlikely(!dst->lwtstate->orig_output)) {
154 pr_warn_once("orig_output not set on dst for prog %s\n",
155 bpf->out.name);
156 kfree_skb(skb);
157 return -EINVAL;
158 }
159
160 return dst->lwtstate->orig_output(net, sk, skb);
161 }
162
163 static int xmit_check_hhlen(struct sk_buff *skb, int hh_len)
164 {
165 if (skb_headroom(skb) < hh_len) {
166 int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
167
168 if (pskb_expand_head(skb, nhead, 0, GFP_ATOMIC))
169 return -ENOMEM;
170 }
171
172 return 0;
173 }
174
175 static int bpf_lwt_xmit_reroute(struct sk_buff *skb)
176 {
177 struct net_device *l3mdev = l3mdev_master_dev_rcu(skb_dst(skb)->dev);
178 int oif = l3mdev ? l3mdev->ifindex : 0;
179 struct dst_entry *dst = NULL;
180 int err = -EAFNOSUPPORT;
181 struct sock *sk;
182 struct net *net;
183 bool ipv4;
184
185 if (skb->protocol == htons(ETH_P_IP))
186 ipv4 = true;
187 else if (skb->protocol == htons(ETH_P_IPV6))
188 ipv4 = false;
189 else
190 goto err;
191
192 sk = sk_to_full_sk(skb->sk);
193 if (sk) {
194 if (sk->sk_bound_dev_if)
195 oif = sk->sk_bound_dev_if;
196 net = sock_net(sk);
197 } else {
198 net = dev_net(skb_dst(skb)->dev);
199 }
200
201 if (ipv4) {
202 struct iphdr *iph = ip_hdr(skb);
203 struct flowi4 fl4 = {};
204 struct rtable *rt;
205
206 fl4.flowi4_oif = oif;
207 fl4.flowi4_mark = skb->mark;
208 fl4.flowi4_uid = sock_net_uid(net, sk);
209 fl4.flowi4_tos = iph->tos & INET_DSCP_MASK;
210 fl4.flowi4_flags = FLOWI_FLAG_ANYSRC;
211 fl4.flowi4_proto = iph->protocol;
212 fl4.daddr = iph->daddr;
213 fl4.saddr = iph->saddr;
214
215 rt = ip_route_output_key(net, &fl4);
216 if (IS_ERR(rt)) {
217 err = PTR_ERR(rt);
218 goto err;
219 }
220 dst = &rt->dst;
221 } else {
222 struct ipv6hdr *iph6 = ipv6_hdr(skb);
223 struct flowi6 fl6 = {};
224
225 fl6.flowi6_oif = oif;
226 fl6.flowi6_mark = skb->mark;
227 fl6.flowi6_uid = sock_net_uid(net, sk);
228 fl6.flowlabel = ip6_flowinfo(iph6);
229 fl6.flowi6_proto = iph6->nexthdr;
230 fl6.daddr = iph6->daddr;
231 fl6.saddr = iph6->saddr;
232
233 dst = ipv6_stub->ipv6_dst_lookup_flow(net, skb->sk, &fl6, NULL);
234 if (IS_ERR(dst)) {
235 err = PTR_ERR(dst);
236 goto err;
237 }
238 }
239 if (unlikely(dst->error)) {
240 err = dst->error;
241 dst_release(dst);
242 goto err;
243 }
244
245 /* Although skb header was reserved in bpf_lwt_push_ip_encap(), it
246 * was done for the previous dst, so we are doing it here again, in
247 * case the new dst needs much more space. The call below is a noop
248 * if there is enough header space in skb.
249 */
250 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
251 if (unlikely(err))
252 goto err;
253
254 skb_dst_drop(skb);
255 skb_dst_set(skb, dst);
256
257 err = dst_output(dev_net(skb_dst(skb)->dev), skb->sk, skb);
258 if (unlikely(err))
259 return net_xmit_errno(err);
260
261 /* ip[6]_finish_output2 understand LWTUNNEL_XMIT_DONE */
262 return LWTUNNEL_XMIT_DONE;
263
264 err:
265 kfree_skb(skb);
266 return err;
267 }
268
269 static int bpf_xmit(struct sk_buff *skb)
270 {
271 struct dst_entry *dst = skb_dst(skb);
272 struct bpf_lwt *bpf;
273
274 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
275 if (bpf->xmit.prog) {
276 int hh_len = dst->dev->hard_header_len;
277 __be16 proto = skb->protocol;
278 int ret;
279
280 ret = run_lwt_bpf(skb, &bpf->xmit, dst, CAN_REDIRECT);
281 switch (ret) {
282 case BPF_OK:
283 /* If the header changed, e.g. via bpf_lwt_push_encap,
284 * BPF_LWT_REROUTE below should have been used if the
285 * protocol was also changed.
286 */
287 if (skb->protocol != proto) {
288 kfree_skb(skb);
289 return -EINVAL;
290 }
291 /* If the header was expanded, headroom might be too
292 * small for L2 header to come, expand as needed.
293 */
294 ret = xmit_check_hhlen(skb, hh_len);
295 if (unlikely(ret))
296 return ret;
297
298 return LWTUNNEL_XMIT_CONTINUE;
299 case BPF_REDIRECT:
300 return LWTUNNEL_XMIT_DONE;
301 case BPF_LWT_REROUTE:
302 return bpf_lwt_xmit_reroute(skb);
303 default:
304 return ret;
305 }
306 }
307
308 return LWTUNNEL_XMIT_CONTINUE;
309 }
310
311 static void bpf_lwt_prog_destroy(struct bpf_lwt_prog *prog)
312 {
313 if (prog->prog)
314 bpf_prog_put(prog->prog);
315
316 kfree(prog->name);
317 }
318
319 static void bpf_destroy_state(struct lwtunnel_state *lwt)
320 {
321 struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt);
322
323 bpf_lwt_prog_destroy(&bpf->in);
324 bpf_lwt_prog_destroy(&bpf->out);
325 bpf_lwt_prog_destroy(&bpf->xmit);
326 }
327
328 static const struct nla_policy bpf_prog_policy[LWT_BPF_PROG_MAX + 1] = {
329 [LWT_BPF_PROG_FD] = { .type = NLA_U32, },
330 [LWT_BPF_PROG_NAME] = { .type = NLA_NUL_STRING,
331 .len = MAX_PROG_NAME },
332 };
333
334 static int bpf_parse_prog(struct nlattr *attr, struct bpf_lwt_prog *prog,
335 enum bpf_prog_type type)
336 {
337 struct nlattr *tb[LWT_BPF_PROG_MAX + 1];
338 struct bpf_prog *p;
339 int ret;
340 u32 fd;
341
342 ret = nla_parse_nested_deprecated(tb, LWT_BPF_PROG_MAX, attr,
343 bpf_prog_policy, NULL);
344 if (ret < 0)
345 return ret;
346
347 if (!tb[LWT_BPF_PROG_FD] || !tb[LWT_BPF_PROG_NAME])
348 return -EINVAL;
349
350 prog->name = nla_memdup(tb[LWT_BPF_PROG_NAME], GFP_ATOMIC);
351 if (!prog->name)
352 return -ENOMEM;
353
354 fd = nla_get_u32(tb[LWT_BPF_PROG_FD]);
355 p = bpf_prog_get_type(fd, type);
356 if (IS_ERR(p))
357 return PTR_ERR(p);
358
359 prog->prog = p;
360
361 return 0;
362 }
363
364 static const struct nla_policy bpf_nl_policy[LWT_BPF_MAX + 1] = {
365 [LWT_BPF_IN] = { .type = NLA_NESTED, },
366 [LWT_BPF_OUT] = { .type = NLA_NESTED, },
367 [LWT_BPF_XMIT] = { .type = NLA_NESTED, },
368 [LWT_BPF_XMIT_HEADROOM] = { .type = NLA_U32 },
369 };
370
371 static int bpf_build_state(struct net *net, struct nlattr *nla,
372 unsigned int family, const void *cfg,
373 struct lwtunnel_state **ts,
374 struct netlink_ext_ack *extack)
375 {
376 struct nlattr *tb[LWT_BPF_MAX + 1];
377 struct lwtunnel_state *newts;
378 struct bpf_lwt *bpf;
379 int ret;
380
381 if (family != AF_INET && family != AF_INET6)
382 return -EAFNOSUPPORT;
383
384 ret = nla_parse_nested_deprecated(tb, LWT_BPF_MAX, nla, bpf_nl_policy,
385 extack);
386 if (ret < 0)
387 return ret;
388
389 if (!tb[LWT_BPF_IN] && !tb[LWT_BPF_OUT] && !tb[LWT_BPF_XMIT])
390 return -EINVAL;
391
392 newts = lwtunnel_state_alloc(sizeof(*bpf));
393 if (!newts)
394 return -ENOMEM;
395
396 newts->type = LWTUNNEL_ENCAP_BPF;
397 bpf = bpf_lwt_lwtunnel(newts);
398
399 if (tb[LWT_BPF_IN]) {
400 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
401 ret = bpf_parse_prog(tb[LWT_BPF_IN], &bpf->in,
402 BPF_PROG_TYPE_LWT_IN);
403 if (ret < 0)
404 goto errout;
405 }
406
407 if (tb[LWT_BPF_OUT]) {
408 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
409 ret = bpf_parse_prog(tb[LWT_BPF_OUT], &bpf->out,
410 BPF_PROG_TYPE_LWT_OUT);
411 if (ret < 0)
412 goto errout;
413 }
414
415 if (tb[LWT_BPF_XMIT]) {
416 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
417 ret = bpf_parse_prog(tb[LWT_BPF_XMIT], &bpf->xmit,
418 BPF_PROG_TYPE_LWT_XMIT);
419 if (ret < 0)
420 goto errout;
421 }
422
423 if (tb[LWT_BPF_XMIT_HEADROOM]) {
424 u32 headroom = nla_get_u32(tb[LWT_BPF_XMIT_HEADROOM]);
425
426 if (headroom > LWT_BPF_MAX_HEADROOM) {
427 ret = -ERANGE;
428 goto errout;
429 }
430
431 newts->headroom = headroom;
432 }
433
434 bpf->family = family;
435 *ts = newts;
436
437 return 0;
438
439 errout:
440 bpf_destroy_state(newts);
441 kfree(newts);
442 return ret;
443 }
444
445 static int bpf_fill_lwt_prog(struct sk_buff *skb, int attr,
446 struct bpf_lwt_prog *prog)
447 {
448 struct nlattr *nest;
449
450 if (!prog->prog)
451 return 0;
452
453 nest = nla_nest_start_noflag(skb, attr);
454 if (!nest)
455 return -EMSGSIZE;
456
457 if (prog->name &&
458 nla_put_string(skb, LWT_BPF_PROG_NAME, prog->name))
459 return -EMSGSIZE;
460
461 return nla_nest_end(skb, nest);
462 }
463
464 static int bpf_fill_encap_info(struct sk_buff *skb, struct lwtunnel_state *lwt)
465 {
466 struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt);
467
468 if (bpf_fill_lwt_prog(skb, LWT_BPF_IN, &bpf->in) < 0 ||
469 bpf_fill_lwt_prog(skb, LWT_BPF_OUT, &bpf->out) < 0 ||
470 bpf_fill_lwt_prog(skb, LWT_BPF_XMIT, &bpf->xmit) < 0)
471 return -EMSGSIZE;
472
473 return 0;
474 }
475
476 static int bpf_encap_nlsize(struct lwtunnel_state *lwtstate)
477 {
478 int nest_len = nla_total_size(sizeof(struct nlattr)) +
479 nla_total_size(MAX_PROG_NAME) + /* LWT_BPF_PROG_NAME */
480 0;
481
482 return nest_len + /* LWT_BPF_IN */
483 nest_len + /* LWT_BPF_OUT */
484 nest_len + /* LWT_BPF_XMIT */
485 0;
486 }
487
488 static int bpf_lwt_prog_cmp(struct bpf_lwt_prog *a, struct bpf_lwt_prog *b)
489 {
490 /* FIXME:
491 * The LWT state is currently rebuilt for delete requests which
492 * results in a new bpf_prog instance. Comparing names for now.
493 */
494 if (!a->name && !b->name)
495 return 0;
496
497 if (!a->name || !b->name)
498 return 1;
499
500 return strcmp(a->name, b->name);
501 }
502
503 static int bpf_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
504 {
505 struct bpf_lwt *a_bpf = bpf_lwt_lwtunnel(a);
506 struct bpf_lwt *b_bpf = bpf_lwt_lwtunnel(b);
507
508 return bpf_lwt_prog_cmp(&a_bpf->in, &b_bpf->in) ||
509 bpf_lwt_prog_cmp(&a_bpf->out, &b_bpf->out) ||
510 bpf_lwt_prog_cmp(&a_bpf->xmit, &b_bpf->xmit);
511 }
512
513 static const struct lwtunnel_encap_ops bpf_encap_ops = {
514 .build_state = bpf_build_state,
515 .destroy_state = bpf_destroy_state,
516 .input = bpf_input,
517 .output = bpf_output,
518 .xmit = bpf_xmit,
519 .fill_encap = bpf_fill_encap_info,
520 .get_encap_size = bpf_encap_nlsize,
521 .cmp_encap = bpf_encap_cmp,
522 .owner = THIS_MODULE,
523 };
524
525 static int handle_gso_type(struct sk_buff *skb, unsigned int gso_type,
526 int encap_len)
527 {
528 struct skb_shared_info *shinfo = skb_shinfo(skb);
529
530 gso_type |= SKB_GSO_DODGY;
531 shinfo->gso_type |= gso_type;
532 skb_decrease_gso_size(shinfo, encap_len);
533 shinfo->gso_segs = 0;
534 return 0;
535 }
536
537 static int handle_gso_encap(struct sk_buff *skb, bool ipv4, int encap_len)
538 {
539 int next_hdr_offset;
540 void *next_hdr;
541 __u8 protocol;
542
543 /* SCTP and UDP_L4 gso need more nuanced handling than what
544 * handle_gso_type() does above: skb_decrease_gso_size() is not enough.
545 * So at the moment only TCP GSO packets are let through.
546 */
547 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
548 return -ENOTSUPP;
549
550 if (ipv4) {
551 protocol = ip_hdr(skb)->protocol;
552 next_hdr_offset = sizeof(struct iphdr);
553 next_hdr = skb_network_header(skb) + next_hdr_offset;
554 } else {
555 protocol = ipv6_hdr(skb)->nexthdr;
556 next_hdr_offset = sizeof(struct ipv6hdr);
557 next_hdr = skb_network_header(skb) + next_hdr_offset;
558 }
559
560 switch (protocol) {
561 case IPPROTO_GRE:
562 next_hdr_offset += sizeof(struct gre_base_hdr);
563 if (next_hdr_offset > encap_len)
564 return -EINVAL;
565
566 if (((struct gre_base_hdr *)next_hdr)->flags & GRE_CSUM)
567 return handle_gso_type(skb, SKB_GSO_GRE_CSUM,
568 encap_len);
569 return handle_gso_type(skb, SKB_GSO_GRE, encap_len);
570
571 case IPPROTO_UDP:
572 next_hdr_offset += sizeof(struct udphdr);
573 if (next_hdr_offset > encap_len)
574 return -EINVAL;
575
576 if (((struct udphdr *)next_hdr)->check)
577 return handle_gso_type(skb, SKB_GSO_UDP_TUNNEL_CSUM,
578 encap_len);
579 return handle_gso_type(skb, SKB_GSO_UDP_TUNNEL, encap_len);
580
581 case IPPROTO_IP:
582 case IPPROTO_IPV6:
583 if (ipv4)
584 return handle_gso_type(skb, SKB_GSO_IPXIP4, encap_len);
585 else
586 return handle_gso_type(skb, SKB_GSO_IPXIP6, encap_len);
587
588 default:
589 return -EPROTONOSUPPORT;
590 }
591 }
592
593 int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len, bool ingress)
594 {
595 struct iphdr *iph;
596 bool ipv4;
597 int err;
598
599 if (unlikely(len < sizeof(struct iphdr) || len > LWT_BPF_MAX_HEADROOM))
600 return -EINVAL;
601
602 /* validate protocol and length */
603 iph = (struct iphdr *)hdr;
604 if (iph->version == 4) {
605 ipv4 = true;
606 if (unlikely(len < iph->ihl * 4))
607 return -EINVAL;
608 } else if (iph->version == 6) {
609 ipv4 = false;
610 if (unlikely(len < sizeof(struct ipv6hdr)))
611 return -EINVAL;
612 } else {
613 return -EINVAL;
614 }
615
616 if (ingress)
617 err = skb_cow_head(skb, len + skb->mac_len);
618 else
619 err = skb_cow_head(skb,
620 len + LL_RESERVED_SPACE(skb_dst(skb)->dev));
621 if (unlikely(err))
622 return err;
623
624 /* push the encap headers and fix pointers */
625 skb_reset_inner_headers(skb);
626 skb_reset_inner_mac_header(skb); /* mac header is not yet set */
627 skb_set_inner_protocol(skb, skb->protocol);
628 skb->encapsulation = 1;
629 skb_push(skb, len);
630 if (ingress)
631 skb_postpush_rcsum(skb, iph, len);
632 skb_reset_network_header(skb);
633 memcpy(skb_network_header(skb), hdr, len);
634 bpf_compute_data_pointers(skb);
635 skb_clear_hash(skb);
636
637 if (ipv4) {
638 skb->protocol = htons(ETH_P_IP);
639 iph = ip_hdr(skb);
640
641 if (!iph->check)
642 iph->check = ip_fast_csum((unsigned char *)iph,
643 iph->ihl);
644 } else {
645 skb->protocol = htons(ETH_P_IPV6);
646 }
647
648 if (skb_is_gso(skb))
649 return handle_gso_encap(skb, ipv4, len);
650
651 return 0;
652 }
653
654 static int __init bpf_lwt_init(void)
655 {
656 return lwtunnel_encap_add_ops(&bpf_encap_ops, LWTUNNEL_ENCAP_BPF);
657 }
658
659 subsys_initcall(bpf_lwt_init)
Kernel DRM miscellaneous fixes and cross-tree changes