net/xfrm/xfrm_input.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * xfrm_input.c
   4  *
   5  * Changes:
   6  *      YOSHIFUJI Hideaki @USAGI
   7  *              Split up af-specific portion
   8  *
   9  */
  10
  11 #include <linux/bottom_half.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/slab.h>
  14 #include <linux/module.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/percpu.h>
  17 #include <net/dst.h>
  18 #include <net/ip.h>
  19 #include <net/xfrm.h>
  20 #include <net/ip_tunnels.h>
  21 #include <net/ip6_tunnel.h>
  22
  23 struct xfrm_trans_tasklet {
  24         struct tasklet_struct tasklet;
  25         struct sk_buff_head queue;
  26 };
  27
  28 struct xfrm_trans_cb {
  29         union {
  30                 struct inet_skb_parm    h4;
  31 #if IS_ENABLED(CONFIG_IPV6)
  32                 struct inet6_skb_parm   h6;
  33 #endif
  34         } header;
  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
  40 static struct kmem_cache *secpath_cachep __read_mostly;
  41
  42 static DEFINE_SPINLOCK(xfrm_input_afinfo_lock);
  43 static struct xfrm_input_afinfo const __rcu *xfrm_input_afinfo[AF_INET6 + 1];
  44
  45 static struct gro_cells gro_cells;
  46 static struct net_device xfrm_napi_dev;
  47
  48 static DEFINE_PER_CPU(struct xfrm_trans_tasklet, xfrm_trans_tasklet);
  49
  50 int xfrm_input_register_afinfo(const struct xfrm_input_afinfo *afinfo)
  51 {
  52         int err = 0;
  53
  54         if (WARN_ON(afinfo->family >= ARRAY_SIZE(xfrm_input_afinfo)))
  55                 return -EAFNOSUPPORT;
  56
  57         spin_lock_bh(&xfrm_input_afinfo_lock);
  58         if (unlikely(xfrm_input_afinfo[afinfo->family] != NULL))
  59                 err = -EEXIST;
  60         else
  61                 rcu_assign_pointer(xfrm_input_afinfo[afinfo->family], afinfo);
  62         spin_unlock_bh(&xfrm_input_afinfo_lock);
  63         return err;
  64 }
  65 EXPORT_SYMBOL(xfrm_input_register_afinfo);
  66
  67 int xfrm_input_unregister_afinfo(const struct xfrm_input_afinfo *afinfo)
  68 {
  69         int err = 0;
  70
  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 }
  82 EXPORT_SYMBOL(xfrm_input_unregister_afinfo);
  83
  84 static const struct xfrm_input_afinfo *xfrm_input_get_afinfo(unsigned int family)
  85 {
  86         const struct xfrm_input_afinfo *afinfo;
  87
  88         if (WARN_ON_ONCE(family >= ARRAY_SIZE(xfrm_input_afinfo)))
  89                 return NULL;
  90
  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
  98 static int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family, u8 protocol,
  99                        int err)
 100 {
 101         int ret;
 102         const struct xfrm_input_afinfo *afinfo = xfrm_input_get_afinfo(family);
 103
 104         if (!afinfo)
 105                 return -EAFNOSUPPORT;
 106
 107         ret = afinfo->callback(skb, protocol, err);
 108         rcu_read_unlock();
 109
 110         return ret;
 111 }
 112
 113 void __secpath_destroy(struct sec_path *sp)
 114 {
 115         int i;
 116         for (i = 0; i < sp->len; i++)
 117                 xfrm_state_put(sp->xvec[i]);
 118         kmem_cache_free(secpath_cachep, sp);
 119 }
 120 EXPORT_SYMBOL(__secpath_destroy);
 121
 122 struct sec_path *secpath_dup(struct sec_path *src)
 123 {
 124         struct sec_path *sp;
 125
 126         sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);
 127         if (!sp)
 128                 return NULL;
 129
 130         sp->len = 0;
 131         sp->olen = 0;
 132
 133         memset(sp->ovec, 0, sizeof(sp->ovec));
 134
 135         if (src) {
 136                 int i;
 137
 138                 memcpy(sp, src, sizeof(*sp));
 139                 for (i = 0; i < sp->len; i++)
 140                         xfrm_state_hold(sp->xvec[i]);
 141         }
 142         refcount_set(&sp->refcnt, 1);
 143         return sp;
 144 }
 145 EXPORT_SYMBOL(secpath_dup);
 146
 147 int secpath_set(struct sk_buff *skb)
 148 {
 149         struct sec_path *sp;
 150
 151         /* Allocate new secpath or COW existing one. */
 152         if (!skb->sp || refcount_read(&skb->sp->refcnt) != 1) {
 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 }
 163 EXPORT_SYMBOL(secpath_set);
 164
 165 /* Fetch spi and seq from ipsec header */
 166
 167 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
 168 {
 169         int offset, offset_seq;
 170         int hlen;
 171
 172         switch (nexthdr) {
 173         case IPPROTO_AH:
 174                 hlen = sizeof(struct ip_auth_hdr);
 175                 offset = offsetof(struct ip_auth_hdr, spi);
 176                 offset_seq = offsetof(struct ip_auth_hdr, seq_no);
 177                 break;
 178         case IPPROTO_ESP:
 179                 hlen = sizeof(struct ip_esp_hdr);
 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;
 186                 *spi = htonl(ntohs(*(__be16 *)(skb_transport_header(skb) + 2)));
 187                 *seq = 0;
 188                 return 0;
 189         default:
 190                 return 1;
 191         }
 192
 193         if (!pskb_may_pull(skb, hlen))
 194                 return -EINVAL;
 195
 196         *spi = *(__be32 *)(skb_transport_header(skb) + offset);
 197         *seq = *(__be32 *)(skb_transport_header(skb) + offset_seq);
 198         return 0;
 199 }
 200 EXPORT_SYMBOL(xfrm_parse_spi);
 201
 202 int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
 203 {
 204         struct xfrm_mode *inner_mode = x->inner_mode;
 205         int err;
 206
 207         err = x->outer_mode->afinfo->extract_input(x, skb);
 208         if (err)
 209                 return err;
 210
 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);
 219 }
 220 EXPORT_SYMBOL(xfrm_prepare_input);
 221
 222 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 223 {
 224         struct net *net = dev_net(skb->dev);
 225         int err;
 226         __be32 seq;
 227         __be32 seq_hi;
 228         struct xfrm_state *x = NULL;
 229         xfrm_address_t *daddr;
 230         struct xfrm_mode *inner_mode;
 231         u32 mark = skb->mark;
 232         unsigned int family = AF_UNSPEC;
 233         int decaps = 0;
 234         int async = 0;
 235         bool xfrm_gro = false;
 236         bool crypto_done = false;
 237         struct xfrm_offload *xo = xfrm_offload(skb);
 238
 239         if (encap_type < 0) {
 240                 x = xfrm_input_state(skb);
 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
 249                         if (encap_type == -1)
 250                                 dev_put(skb->dev);
 251                         goto drop;
 252                 }
 253
 254                 family = x->outer_mode->afinfo->family;
 255
 256                 /* An encap_type of -1 indicates async resumption. */
 257                 if (encap_type == -1) {
 258                         async = 1;
 259                         seq = XFRM_SKB_CB(skb)->seq.input.low;
 260                         goto resume;
 261                 }
 262
 263                 /* encap_type < -1 indicates a GRO call. */
 264                 encap_type = 0;
 265                 seq = XFRM_SPI_SKB_CB(skb)->seq;
 266
 267                 if (xo && (xo->flags & CRYPTO_DONE)) {
 268                         crypto_done = true;
 269                         x = xfrm_input_state(skb);
 270                         family = XFRM_SPI_SKB_CB(skb)->family;
 271
 272                         if (!(xo->status & CRYPTO_SUCCESS)) {
 273                                 if (xo->status &
 274                                     (CRYPTO_TRANSPORT_AH_AUTH_FAILED |
 275                                      CRYPTO_TRANSPORT_ESP_AUTH_FAILED |
 276                                      CRYPTO_TUNNEL_AH_AUTH_FAILED |
 277                                      CRYPTO_TUNNEL_ESP_AUTH_FAILED)) {
 278
 279                                         xfrm_audit_state_icvfail(x, skb,
 280                                                                  x->type->proto);
 281                                         x->stats.integrity_failed++;
 282                                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 283                                         goto drop;
 284                                 }
 285
 286                                 if (xo->status & CRYPTO_INVALID_PROTOCOL) {
 287                                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 288                                         goto drop;
 289                                 }
 290
 291                                 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
 292                                 goto drop;
 293                         }
 294
 295                         if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
 296                                 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 297                                 goto drop;
 298                         }
 299                 }
 300
 301                 goto lock;
 302         }
 303
 304         family = XFRM_SPI_SKB_CB(skb)->family;
 305
 306         /* if tunnel is present override skb->mark value with tunnel i_key */
 307         switch (family) {
 308         case AF_INET:
 309                 if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4)
 310                         mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4->parms.i_key);
 311                 break;
 312         case AF_INET6:
 313                 if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6)
 314                         mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6->parms.i_key);
 315                 break;
 316         }
 317
 318         err = secpath_set(skb);
 319         if (err) {
 320                 XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
 321                 goto drop;
 322         }
 323
 324         seq = 0;
 325         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
 326                 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 327                 goto drop;
 328         }
 329
 330         daddr = (xfrm_address_t *)(skb_network_header(skb) +
 331                                    XFRM_SPI_SKB_CB(skb)->daddroff);
 332         do {
 333                 if (skb->sp->len == XFRM_MAX_DEPTH) {
 334                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
 335                         goto drop;
 336                 }
 337
 338                 x = xfrm_state_lookup(net, mark, daddr, spi, nexthdr, family);
 339                 if (x == NULL) {
 340                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
 341                         xfrm_audit_state_notfound(skb, family, spi, seq);
 342                         goto drop;
 343                 }
 344
 345                 skb->sp->xvec[skb->sp->len++] = x;
 346
 347                 skb_dst_force(skb);
 348                 if (!skb_dst(skb)) {
 349                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
 350                         goto drop;
 351                 }
 352
 353 lock:
 354                 spin_lock(&x->lock);
 355
 356                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 357                         if (x->km.state == XFRM_STATE_ACQ)
 358                                 XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
 359                         else
 360                                 XFRM_INC_STATS(net,
 361                                                LINUX_MIB_XFRMINSTATEINVALID);
 362                         goto drop_unlock;
 363                 }
 364
 365                 if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
 366                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
 367                         goto drop_unlock;
 368                 }
 369
 370                 if (x->repl->check(x, skb, seq)) {
 371                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 372                         goto drop_unlock;
 373                 }
 374
 375                 if (xfrm_state_check_expire(x)) {
 376                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
 377                         goto drop_unlock;
 378                 }
 379
 380                 spin_unlock(&x->lock);
 381
 382                 if (xfrm_tunnel_check(skb, x, family)) {
 383                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 384                         goto drop;
 385                 }
 386
 387                 seq_hi = htonl(xfrm_replay_seqhi(x, seq));
 388
 389                 XFRM_SKB_CB(skb)->seq.input.low = seq;
 390                 XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;
 391
 392                 dev_hold(skb->dev);
 393
 394                 if (crypto_done)
 395                         nexthdr = x->type_offload->input_tail(x, skb);
 396                 else
 397                         nexthdr = x->type->input(x, skb);
 398
 399                 if (nexthdr == -EINPROGRESS)
 400                         return 0;
 401 resume:
 402                 dev_put(skb->dev);
 403
 404                 spin_lock(&x->lock);
 405                 if (nexthdr < 0) {
 406                         if (nexthdr == -EBADMSG) {
 407                                 xfrm_audit_state_icvfail(x, skb,
 408                                                          x->type->proto);
 409                                 x->stats.integrity_failed++;
 410                         }
 411                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 412                         goto drop_unlock;
 413                 }
 414
 415                 /* only the first xfrm gets the encap type */
 416                 encap_type = 0;
 417
 418                 if (x->repl->recheck(x, skb, seq)) {
 419                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 420                         goto drop_unlock;
 421                 }
 422
 423                 x->repl->advance(x, seq);
 424
 425                 x->curlft.bytes += skb->len;
 426                 x->curlft.packets++;
 427
 428                 spin_unlock(&x->lock);
 429
 430                 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
 431
 432                 inner_mode = x->inner_mode;
 433
 434                 if (x->sel.family == AF_UNSPEC) {
 435                         inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 436                         if (inner_mode == NULL) {
 437                                 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 438                                 goto drop;
 439                         }
 440                 }
 441
 442                 if (inner_mode->input(x, skb)) {
 443                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 444                         goto drop;
 445                 }
 446
 447                 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 448                         decaps = 1;
 449                         break;
 450                 }
 451
 452                 /*
 453                  * We need the inner address.  However, we only get here for
 454                  * transport mode so the outer address is identical.
 455                  */
 456                 daddr = &x->id.daddr;
 457                 family = x->outer_mode->afinfo->family;
 458
 459                 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
 460                 if (err < 0) {
 461                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 462                         goto drop;
 463                 }
 464                 crypto_done = false;
 465         } while (!err);
 466
 467         err = xfrm_rcv_cb(skb, family, x->type->proto, 0);
 468         if (err)
 469                 goto drop;
 470
 471         nf_reset(skb);
 472
 473         if (decaps) {
 474                 if (skb->sp)
 475                         skb->sp->olen = 0;
 476                 skb_dst_drop(skb);
 477                 gro_cells_receive(&gro_cells, skb);
 478                 return 0;
 479         } else {
 480                 xo = xfrm_offload(skb);
 481                 if (xo)
 482                         xfrm_gro = xo->flags & XFRM_GRO;
 483
 484                 err = x->inner_mode->afinfo->transport_finish(skb, xfrm_gro || async);
 485                 if (xfrm_gro) {
 486                         if (skb->sp)
 487                                 skb->sp->olen = 0;
 488                         skb_dst_drop(skb);
 489                         gro_cells_receive(&gro_cells, skb);
 490                         return err;
 491                 }
 492
 493                 return err;
 494         }
 495
 496 drop_unlock:
 497         spin_unlock(&x->lock);
 498 drop:
 499         xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1);
 500         kfree_skb(skb);
 501         return 0;
 502 }
 503 EXPORT_SYMBOL(xfrm_input);
 504
 505 int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
 506 {
 507         return xfrm_input(skb, nexthdr, 0, -1);
 508 }
 509 EXPORT_SYMBOL(xfrm_input_resume);
 510
 511 static void xfrm_trans_reinject(unsigned long data)
 512 {
 513         struct xfrm_trans_tasklet *trans = (void *)data;
 514         struct sk_buff_head queue;
 515         struct sk_buff *skb;
 516
 517         __skb_queue_head_init(&queue);
 518         skb_queue_splice_init(&trans->queue, &queue);
 519
 520         while ((skb = __skb_dequeue(&queue)))
 521                 XFRM_TRANS_SKB_CB(skb)->finish(dev_net(skb->dev), NULL, skb);
 522 }
 523
 524 int xfrm_trans_queue(struct sk_buff *skb,
 525                      int (*finish)(struct net *, struct sock *,
 526                                    struct sk_buff *))
 527 {
 528         struct xfrm_trans_tasklet *trans;
 529
 530         trans = this_cpu_ptr(&xfrm_trans_tasklet);
 531
 532         if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
 533                 return -ENOBUFS;
 534
 535         XFRM_TRANS_SKB_CB(skb)->finish = finish;
 536         __skb_queue_tail(&trans->queue, skb);
 537         tasklet_schedule(&trans->tasklet);
 538         return 0;
 539 }
 540 EXPORT_SYMBOL(xfrm_trans_queue);
 541
 542 void __init xfrm_input_init(void)
 543 {
 544         int err;
 545         int i;
 546
 547         init_dummy_netdev(&xfrm_napi_dev);
 548         err = gro_cells_init(&gro_cells, &xfrm_napi_dev);
 549         if (err)
 550                 gro_cells.cells = NULL;
 551
 552         secpath_cachep = kmem_cache_create("secpath_cache",
 553                                            sizeof(struct sec_path),
 554                                            0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
 555                                            NULL);
 556
 557         for_each_possible_cpu(i) {
 558                 struct xfrm_trans_tasklet *trans;
 559
 560                 trans = &per_cpu(xfrm_trans_tasklet, i);
 561                 __skb_queue_head_init(&trans->queue);
 562                 tasklet_init(&trans->tasklet, xfrm_trans_reinject,
 563                              (unsigned long)trans);
 564         }
 565 }