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xfrm_user: prevent leaking 2 bytes of kernel memory
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b2441318 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT
2/*
3 * xfrm_input.c
4 *
5 * Changes:
6 * YOSHIFUJI Hideaki @USAGI
7 * Split up af-specific portion
a716c119 8 *
1da177e4
LT
9 */
10
acf568ee
HX
11#include <linux/bottom_half.h>
12#include <linux/interrupt.h>
1da177e4
LT
13#include <linux/slab.h>
14#include <linux/module.h>
716062fd 15#include <linux/netdevice.h>
acf568ee 16#include <linux/percpu.h>
716062fd 17#include <net/dst.h>
1da177e4
LT
18#include <net/ip.h>
19#include <net/xfrm.h>
049f8e2e
AD
20#include <net/ip_tunnels.h>
21#include <net/ip6_tunnel.h>
1da177e4 22
acf568ee
HX
23struct xfrm_trans_tasklet {
24 struct tasklet_struct tasklet;
25 struct sk_buff_head queue;
26};
27
28struct xfrm_trans_cb {
f14494ef
SK
29 union {
30 struct inet_skb_parm h4;
31#if IS_ENABLED(CONFIG_IPV6)
32 struct inet6_skb_parm h6;
33#endif
34 } header;
acf568ee
HX
35 int (*finish)(struct net *net, struct sock *sk, struct sk_buff *skb);
36};
37
38#define XFRM_TRANS_SKB_CB(__skb) ((struct xfrm_trans_cb *)&((__skb)->cb[0]))
39
e18b890b 40static struct kmem_cache *secpath_cachep __read_mostly;
1da177e4 41
2f32b51b 42static DEFINE_SPINLOCK(xfrm_input_afinfo_lock);
960fdfde 43static struct xfrm_input_afinfo const __rcu *xfrm_input_afinfo[AF_INET6 + 1];
2f32b51b 44
1995876a
SK
45static struct gro_cells gro_cells;
46static struct net_device xfrm_napi_dev;
47
acf568ee
HX
48static DEFINE_PER_CPU(struct xfrm_trans_tasklet, xfrm_trans_tasklet);
49
960fdfde 50int xfrm_input_register_afinfo(const struct xfrm_input_afinfo *afinfo)
2f32b51b
SK
51{
52 int err = 0;
53
960fdfde 54 if (WARN_ON(afinfo->family >= ARRAY_SIZE(xfrm_input_afinfo)))
2f32b51b 55 return -EAFNOSUPPORT;
960fdfde 56
2f32b51b
SK
57 spin_lock_bh(&xfrm_input_afinfo_lock);
58 if (unlikely(xfrm_input_afinfo[afinfo->family] != NULL))
f31e8d4f 59 err = -EEXIST;
2f32b51b
SK
60 else
61 rcu_assign_pointer(xfrm_input_afinfo[afinfo->family], afinfo);
62 spin_unlock_bh(&xfrm_input_afinfo_lock);
63 return err;
64}
65EXPORT_SYMBOL(xfrm_input_register_afinfo);
66
960fdfde 67int xfrm_input_unregister_afinfo(const struct xfrm_input_afinfo *afinfo)
2f32b51b
SK
68{
69 int err = 0;
70
2f32b51b
SK
71 spin_lock_bh(&xfrm_input_afinfo_lock);
72 if (likely(xfrm_input_afinfo[afinfo->family] != NULL)) {
73 if (unlikely(xfrm_input_afinfo[afinfo->family] != afinfo))
74 err = -EINVAL;
75 else
76 RCU_INIT_POINTER(xfrm_input_afinfo[afinfo->family], NULL);
77 }
78 spin_unlock_bh(&xfrm_input_afinfo_lock);
79 synchronize_rcu();
80 return err;
81}
82EXPORT_SYMBOL(xfrm_input_unregister_afinfo);
83
960fdfde 84static const struct xfrm_input_afinfo *xfrm_input_get_afinfo(unsigned int family)
2f32b51b 85{
960fdfde 86 const struct xfrm_input_afinfo *afinfo;
2f32b51b 87
960fdfde 88 if (WARN_ON_ONCE(family >= ARRAY_SIZE(xfrm_input_afinfo)))
2f32b51b 89 return NULL;
960fdfde 90
2f32b51b
SK
91 rcu_read_lock();
92 afinfo = rcu_dereference(xfrm_input_afinfo[family]);
93 if (unlikely(!afinfo))
94 rcu_read_unlock();
95 return afinfo;
96}
97
2f32b51b
SK
98static int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family, u8 protocol,
99 int err)
100{
101 int ret;
960fdfde 102 const struct xfrm_input_afinfo *afinfo = xfrm_input_get_afinfo(family);
2f32b51b
SK
103
104 if (!afinfo)
105 return -EAFNOSUPPORT;
106
107 ret = afinfo->callback(skb, protocol, err);
960fdfde 108 rcu_read_unlock();
2f32b51b
SK
109
110 return ret;
111}
112
1da177e4
LT
113void __secpath_destroy(struct sec_path *sp)
114{
115 int i;
116 for (i = 0; i < sp->len; i++)
dbe5b4aa 117 xfrm_state_put(sp->xvec[i]);
1da177e4
LT
118 kmem_cache_free(secpath_cachep, sp);
119}
120EXPORT_SYMBOL(__secpath_destroy);
121
122struct sec_path *secpath_dup(struct sec_path *src)
123{
124 struct sec_path *sp;
125
54e6ecb2 126 sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);
1da177e4
LT
127 if (!sp)
128 return NULL;
129
130 sp->len = 0;
54ef207a
SK
131 sp->olen = 0;
132
d77e38e6
SK
133 memset(sp->ovec, 0, sizeof(sp->ovec[XFRM_MAX_OFFLOAD_DEPTH]));
134
1da177e4
LT
135 if (src) {
136 int i;
137
138 memcpy(sp, src, sizeof(*sp));
139 for (i = 0; i < sp->len; i++)
dbe5b4aa 140 xfrm_state_hold(sp->xvec[i]);
1da177e4 141 }
55eabed6 142 refcount_set(&sp->refcnt, 1);
1da177e4
LT
143 return sp;
144}
145EXPORT_SYMBOL(secpath_dup);
146
b0fcee82
SK
147int secpath_set(struct sk_buff *skb)
148{
149 struct sec_path *sp;
150
151 /* Allocate new secpath or COW existing one. */
55eabed6 152 if (!skb->sp || refcount_read(&skb->sp->refcnt) != 1) {
b0fcee82
SK
153 sp = secpath_dup(skb->sp);
154 if (!sp)
155 return -ENOMEM;
156
157 if (skb->sp)
158 secpath_put(skb->sp);
159 skb->sp = sp;
160 }
161 return 0;
162}
163EXPORT_SYMBOL(secpath_set);
164
1da177e4
LT
165/* Fetch spi and seq from ipsec header */
166
6067b2ba 167int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
1da177e4
LT
168{
169 int offset, offset_seq;
44072500 170 int hlen;
1da177e4
LT
171
172 switch (nexthdr) {
173 case IPPROTO_AH:
44072500 174 hlen = sizeof(struct ip_auth_hdr);
1da177e4
LT
175 offset = offsetof(struct ip_auth_hdr, spi);
176 offset_seq = offsetof(struct ip_auth_hdr, seq_no);
177 break;
178 case IPPROTO_ESP:
44072500 179 hlen = sizeof(struct ip_esp_hdr);
1da177e4
LT
180 offset = offsetof(struct ip_esp_hdr, spi);
181 offset_seq = offsetof(struct ip_esp_hdr, seq_no);
182 break;
183 case IPPROTO_COMP:
184 if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
185 return -EINVAL;
3e94c2dc 186 *spi = htonl(ntohs(*(__be16 *)(skb_transport_header(skb) + 2)));
1da177e4
LT
187 *seq = 0;
188 return 0;
189 default:
190 return 1;
191 }
192
44072500 193 if (!pskb_may_pull(skb, hlen))
1da177e4
LT
194 return -EINVAL;
195
3e94c2dc
WC
196 *spi = *(__be32 *)(skb_transport_header(skb) + offset);
197 *seq = *(__be32 *)(skb_transport_header(skb) + offset_seq);
1da177e4
LT
198 return 0;
199}
1e295370 200EXPORT_SYMBOL(xfrm_parse_spi);
1da177e4 201
227620e2
HX
202int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
203{
df9dcb45 204 struct xfrm_mode *inner_mode = x->inner_mode;
227620e2
HX
205 int err;
206
207 err = x->outer_mode->afinfo->extract_input(x, skb);
208 if (err)
209 return err;
210
df9dcb45
KM
211 if (x->sel.family == AF_UNSPEC) {
212 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
213 if (inner_mode == NULL)
214 return -EAFNOSUPPORT;
215 }
216
217 skb->protocol = inner_mode->afinfo->eth_proto;
218 return inner_mode->input2(x, skb);
227620e2
HX
219}
220EXPORT_SYMBOL(xfrm_prepare_input);
221
716062fd
HX
222int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
223{
bd235e3c 224 struct net *net = dev_net(skb->dev);
716062fd
HX
225 int err;
226 __be32 seq;
2cd08467 227 __be32 seq_hi;
3328715e 228 struct xfrm_state *x = NULL;
1bf06cd2 229 xfrm_address_t *daddr;
df9dcb45 230 struct xfrm_mode *inner_mode;
049f8e2e 231 u32 mark = skb->mark;
4ce3dbe3 232 unsigned int family = AF_UNSPEC;
716062fd 233 int decaps = 0;
1bf06cd2 234 int async = 0;
7785bba2 235 bool xfrm_gro = false;
d77e38e6
SK
236 bool crypto_done = false;
237 struct xfrm_offload *xo = xfrm_offload(skb);
1bf06cd2 238
1bf06cd2 239 if (encap_type < 0) {
00501121 240 x = xfrm_input_state(skb);
4ce3dbe3
AH
241
242 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
243 if (x->km.state == XFRM_STATE_ACQ)
244 XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
245 else
246 XFRM_INC_STATS(net,
247 LINUX_MIB_XFRMINSTATEINVALID);
248 goto drop;
249 }
250
3328715e 251 family = x->outer_mode->afinfo->family;
7785bba2
SK
252
253 /* An encap_type of -1 indicates async resumption. */
254 if (encap_type == -1) {
255 async = 1;
256 seq = XFRM_SKB_CB(skb)->seq.input.low;
257 goto resume;
258 }
bcd1f8a4 259
7785bba2
SK
260 /* encap_type < -1 indicates a GRO call. */
261 encap_type = 0;
262 seq = XFRM_SPI_SKB_CB(skb)->seq;
716062fd 263
bcd1f8a4
SK
264 if (xo && (xo->flags & CRYPTO_DONE)) {
265 crypto_done = true;
266 x = xfrm_input_state(skb);
267 family = XFRM_SPI_SKB_CB(skb)->family;
268
269 if (!(xo->status & CRYPTO_SUCCESS)) {
270 if (xo->status &
271 (CRYPTO_TRANSPORT_AH_AUTH_FAILED |
272 CRYPTO_TRANSPORT_ESP_AUTH_FAILED |
273 CRYPTO_TUNNEL_AH_AUTH_FAILED |
274 CRYPTO_TUNNEL_ESP_AUTH_FAILED)) {
275
276 xfrm_audit_state_icvfail(x, skb,
277 x->type->proto);
278 x->stats.integrity_failed++;
279 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
280 goto drop;
281 }
282
47ebcc0b
YK
283 if (xo->status & CRYPTO_INVALID_PROTOCOL) {
284 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
285 goto drop;
286 }
287
bcd1f8a4 288 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
d77e38e6
SK
289 goto drop;
290 }
291
bcd1f8a4
SK
292 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
293 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
294 goto drop;
295 }
d77e38e6
SK
296 }
297
7785bba2 298 goto lock;
1bf06cd2 299 }
716062fd 300
3328715e
SK
301 family = XFRM_SPI_SKB_CB(skb)->family;
302
049f8e2e 303 /* if tunnel is present override skb->mark value with tunnel i_key */
1625f452
AK
304 switch (family) {
305 case AF_INET:
306 if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4)
049f8e2e 307 mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4->parms.i_key);
1625f452
AK
308 break;
309 case AF_INET6:
310 if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6)
049f8e2e 311 mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6->parms.i_key);
1625f452 312 break;
049f8e2e
AD
313 }
314
b0fcee82
SK
315 err = secpath_set(skb);
316 if (err) {
317 XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
318 goto drop;
b2aa5e9d
HX
319 }
320
716062fd 321 seq = 0;
0aa64774 322 if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
59c9940e 323 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
716062fd 324 goto drop;
0aa64774 325 }
716062fd 326
cb79a180
FW
327 daddr = (xfrm_address_t *)(skb_network_header(skb) +
328 XFRM_SPI_SKB_CB(skb)->daddroff);
716062fd 329 do {
0aa64774 330 if (skb->sp->len == XFRM_MAX_DEPTH) {
59c9940e 331 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
716062fd 332 goto drop;
0aa64774 333 }
716062fd 334
049f8e2e 335 x = xfrm_state_lookup(net, mark, daddr, spi, nexthdr, family);
0aa64774 336 if (x == NULL) {
59c9940e 337 XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
afeb14b4 338 xfrm_audit_state_notfound(skb, family, spi, seq);
716062fd 339 goto drop;
0aa64774 340 }
716062fd 341
b2aa5e9d
HX
342 skb->sp->xvec[skb->sp->len++] = x;
343
7785bba2 344lock:
716062fd 345 spin_lock(&x->lock);
4c4d41f2 346
0aa64774 347 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
dc0565ce
LR
348 if (x->km.state == XFRM_STATE_ACQ)
349 XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
350 else
351 XFRM_INC_STATS(net,
352 LINUX_MIB_XFRMINSTATEINVALID);
716062fd 353 goto drop_unlock;
0aa64774 354 }
716062fd 355
3de77cf2
DM
356 if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
357 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
358 goto drop_unlock;
359 }
360
36ae0148 361 if (x->repl->check(x, skb, seq)) {
59c9940e 362 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
716062fd 363 goto drop_unlock;
0aa64774 364 }
716062fd 365
0aa64774 366 if (xfrm_state_check_expire(x)) {
59c9940e 367 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
716062fd 368 goto drop_unlock;
0aa64774 369 }
716062fd 370
0ebea8ef
HX
371 spin_unlock(&x->lock);
372
68c11e98
AD
373 if (xfrm_tunnel_check(skb, x, family)) {
374 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
375 goto drop;
376 }
377
2cd08467
SK
378 seq_hi = htonl(xfrm_replay_seqhi(x, seq));
379
1ce3644a 380 XFRM_SKB_CB(skb)->seq.input.low = seq;
2cd08467 381 XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;
1bf06cd2 382
3bc07321 383 skb_dst_force(skb);
071d36bf 384 dev_hold(skb->dev);
3bc07321 385
d77e38e6
SK
386 if (crypto_done)
387 nexthdr = x->type_offload->input_tail(x, skb);
388 else
389 nexthdr = x->type->input(x, skb);
0ebea8ef 390
1bf06cd2
HX
391 if (nexthdr == -EINPROGRESS)
392 return 0;
1bf06cd2 393resume:
071d36bf
SAK
394 dev_put(skb->dev);
395
0ebea8ef 396 spin_lock(&x->lock);
668dc8af 397 if (nexthdr <= 0) {
9dd3245a
HX
398 if (nexthdr == -EBADMSG) {
399 xfrm_audit_state_icvfail(x, skb,
400 x->type->proto);
668dc8af 401 x->stats.integrity_failed++;
9dd3245a 402 }
59c9940e 403 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
716062fd 404 goto drop_unlock;
668dc8af 405 }
716062fd 406
716062fd
HX
407 /* only the first xfrm gets the encap type */
408 encap_type = 0;
409
3b59df46 410 if (async && x->repl->recheck(x, skb, seq)) {
bcf66bf5
SK
411 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
412 goto drop_unlock;
413 }
414
9fdc4883 415 x->repl->advance(x, seq);
716062fd
HX
416
417 x->curlft.bytes += skb->len;
418 x->curlft.packets++;
419
420 spin_unlock(&x->lock);
421
60d5fcfb
HX
422 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
423
df9dcb45
KM
424 inner_mode = x->inner_mode;
425
426 if (x->sel.family == AF_UNSPEC) {
427 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
cb866e32
SK
428 if (inner_mode == NULL) {
429 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
df9dcb45 430 goto drop;
cb866e32 431 }
df9dcb45
KM
432 }
433
434 if (inner_mode->input(x, skb)) {
59c9940e 435 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
716062fd 436 goto drop;
0aa64774 437 }
716062fd
HX
438
439 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
440 decaps = 1;
441 break;
442 }
443
1bf06cd2
HX
444 /*
445 * We need the inner address. However, we only get here for
446 * transport mode so the outer address is identical.
447 */
448 daddr = &x->id.daddr;
2fcb45b6 449 family = x->outer_mode->afinfo->family;
1bf06cd2 450
716062fd 451 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
0aa64774 452 if (err < 0) {
59c9940e 453 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
716062fd 454 goto drop;
0aa64774 455 }
716062fd
HX
456 } while (!err);
457
3328715e
SK
458 err = xfrm_rcv_cb(skb, family, x->type->proto, 0);
459 if (err)
460 goto drop;
461
716062fd
HX
462 nf_reset(skb);
463
464 if (decaps) {
23e9fcfe
AK
465 if (skb->sp)
466 skb->sp->olen = 0;
adf30907 467 skb_dst_drop(skb);
1995876a 468 gro_cells_receive(&gro_cells, skb);
716062fd
HX
469 return 0;
470 } else {
7785bba2
SK
471 xo = xfrm_offload(skb);
472 if (xo)
473 xfrm_gro = xo->flags & XFRM_GRO;
474
cfcf99f9 475 err = x->inner_mode->afinfo->transport_finish(skb, xfrm_gro || async);
7785bba2 476 if (xfrm_gro) {
23e9fcfe
AK
477 if (skb->sp)
478 skb->sp->olen = 0;
7785bba2
SK
479 skb_dst_drop(skb);
480 gro_cells_receive(&gro_cells, skb);
481 return err;
482 }
483
484 return err;
716062fd
HX
485 }
486
487drop_unlock:
488 spin_unlock(&x->lock);
716062fd 489drop:
3328715e 490 xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1);
716062fd
HX
491 kfree_skb(skb);
492 return 0;
493}
494EXPORT_SYMBOL(xfrm_input);
495
1bf06cd2
HX
496int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
497{
498 return xfrm_input(skb, nexthdr, 0, -1);
499}
500EXPORT_SYMBOL(xfrm_input_resume);
501
acf568ee
HX
502static void xfrm_trans_reinject(unsigned long data)
503{
504 struct xfrm_trans_tasklet *trans = (void *)data;
505 struct sk_buff_head queue;
506 struct sk_buff *skb;
507
508 __skb_queue_head_init(&queue);
509 skb_queue_splice_init(&trans->queue, &queue);
510
511 while ((skb = __skb_dequeue(&queue)))
512 XFRM_TRANS_SKB_CB(skb)->finish(dev_net(skb->dev), NULL, skb);
513}
514
515int xfrm_trans_queue(struct sk_buff *skb,
516 int (*finish)(struct net *, struct sock *,
517 struct sk_buff *))
518{
519 struct xfrm_trans_tasklet *trans;
520
521 trans = this_cpu_ptr(&xfrm_trans_tasklet);
522
523 if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
524 return -ENOBUFS;
525
526 XFRM_TRANS_SKB_CB(skb)->finish = finish;
d16b46e4 527 __skb_queue_tail(&trans->queue, skb);
acf568ee
HX
528 tasklet_schedule(&trans->tasklet);
529 return 0;
530}
531EXPORT_SYMBOL(xfrm_trans_queue);
532
1da177e4
LT
533void __init xfrm_input_init(void)
534{
1995876a 535 int err;
acf568ee 536 int i;
1995876a
SK
537
538 init_dummy_netdev(&xfrm_napi_dev);
539 err = gro_cells_init(&gro_cells, &xfrm_napi_dev);
540 if (err)
541 gro_cells.cells = NULL;
542
1da177e4
LT
543 secpath_cachep = kmem_cache_create("secpath_cache",
544 sizeof(struct sec_path),
e5d679f3 545 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
20c2df83 546 NULL);
acf568ee
HX
547
548 for_each_possible_cpu(i) {
549 struct xfrm_trans_tasklet *trans;
550
551 trans = &per_cpu(xfrm_trans_tasklet, i);
552 __skb_queue_head_init(&trans->queue);
553 tasklet_init(&trans->tasklet, xfrm_trans_reinject,
554 (unsigned long)trans);
555 }
1da177e4 556}