net/xfrm/xfrm_input.c

   1 /*
   2  * xfrm_input.c
   3  *
   4  * Changes:
   5  *      YOSHIFUJI Hideaki @USAGI
   6  *              Split up af-specific portion
   7  *
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/module.h>
  12 #include <linux/netdevice.h>
  13 #include <net/dst.h>
  14 #include <net/ip.h>
  15 #include <net/xfrm.h>
  16 #include <net/ip_tunnels.h>
  17 #include <net/ip6_tunnel.h>
  18
  19 static struct kmem_cache *secpath_cachep __read_mostly;
  20
  21 static DEFINE_SPINLOCK(xfrm_input_afinfo_lock);
  22 static struct xfrm_input_afinfo __rcu *xfrm_input_afinfo[NPROTO];
  23
  24 int xfrm_input_register_afinfo(struct xfrm_input_afinfo *afinfo)
  25 {
  26         int err = 0;
  27
  28         if (unlikely(afinfo == NULL))
  29                 return -EINVAL;
  30         if (unlikely(afinfo->family >= NPROTO))
  31                 return -EAFNOSUPPORT;
  32         spin_lock_bh(&xfrm_input_afinfo_lock);
  33         if (unlikely(xfrm_input_afinfo[afinfo->family] != NULL))
  34                 err = -EEXIST;
  35         else
  36                 rcu_assign_pointer(xfrm_input_afinfo[afinfo->family], afinfo);
  37         spin_unlock_bh(&xfrm_input_afinfo_lock);
  38         return err;
  39 }
  40 EXPORT_SYMBOL(xfrm_input_register_afinfo);
  41
  42 int xfrm_input_unregister_afinfo(struct xfrm_input_afinfo *afinfo)
  43 {
  44         int err = 0;
  45
  46         if (unlikely(afinfo == NULL))
  47                 return -EINVAL;
  48         if (unlikely(afinfo->family >= NPROTO))
  49                 return -EAFNOSUPPORT;
  50         spin_lock_bh(&xfrm_input_afinfo_lock);
  51         if (likely(xfrm_input_afinfo[afinfo->family] != NULL)) {
  52                 if (unlikely(xfrm_input_afinfo[afinfo->family] != afinfo))
  53                         err = -EINVAL;
  54                 else
  55                         RCU_INIT_POINTER(xfrm_input_afinfo[afinfo->family], NULL);
  56         }
  57         spin_unlock_bh(&xfrm_input_afinfo_lock);
  58         synchronize_rcu();
  59         return err;
  60 }
  61 EXPORT_SYMBOL(xfrm_input_unregister_afinfo);
  62
  63 static struct xfrm_input_afinfo *xfrm_input_get_afinfo(unsigned int family)
  64 {
  65         struct xfrm_input_afinfo *afinfo;
  66
  67         if (unlikely(family >= NPROTO))
  68                 return NULL;
  69         rcu_read_lock();
  70         afinfo = rcu_dereference(xfrm_input_afinfo[family]);
  71         if (unlikely(!afinfo))
  72                 rcu_read_unlock();
  73         return afinfo;
  74 }
  75
  76 static void xfrm_input_put_afinfo(struct xfrm_input_afinfo *afinfo)
  77 {
  78         rcu_read_unlock();
  79 }
  80
  81 static int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family, u8 protocol,
  82                        int err)
  83 {
  84         int ret;
  85         struct xfrm_input_afinfo *afinfo = xfrm_input_get_afinfo(family);
  86
  87         if (!afinfo)
  88                 return -EAFNOSUPPORT;
  89
  90         ret = afinfo->callback(skb, protocol, err);
  91         xfrm_input_put_afinfo(afinfo);
  92
  93         return ret;
  94 }
  95
  96 void __secpath_destroy(struct sec_path *sp)
  97 {
  98         int i;
  99         for (i = 0; i < sp->len; i++)
 100                 xfrm_state_put(sp->xvec[i]);
 101         kmem_cache_free(secpath_cachep, sp);
 102 }
 103 EXPORT_SYMBOL(__secpath_destroy);
 104
 105 struct sec_path *secpath_dup(struct sec_path *src)
 106 {
 107         struct sec_path *sp;
 108
 109         sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);
 110         if (!sp)
 111                 return NULL;
 112
 113         sp->len = 0;
 114         if (src) {
 115                 int i;
 116
 117                 memcpy(sp, src, sizeof(*sp));
 118                 for (i = 0; i < sp->len; i++)
 119                         xfrm_state_hold(sp->xvec[i]);
 120         }
 121         atomic_set(&sp->refcnt, 1);
 122         return sp;
 123 }
 124 EXPORT_SYMBOL(secpath_dup);
 125
 126 /* Fetch spi and seq from ipsec header */
 127
 128 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
 129 {
 130         int offset, offset_seq;
 131         int hlen;
 132
 133         switch (nexthdr) {
 134         case IPPROTO_AH:
 135                 hlen = sizeof(struct ip_auth_hdr);
 136                 offset = offsetof(struct ip_auth_hdr, spi);
 137                 offset_seq = offsetof(struct ip_auth_hdr, seq_no);
 138                 break;
 139         case IPPROTO_ESP:
 140                 hlen = sizeof(struct ip_esp_hdr);
 141                 offset = offsetof(struct ip_esp_hdr, spi);
 142                 offset_seq = offsetof(struct ip_esp_hdr, seq_no);
 143                 break;
 144         case IPPROTO_COMP:
 145                 if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
 146                         return -EINVAL;
 147                 *spi = htonl(ntohs(*(__be16 *)(skb_transport_header(skb) + 2)));
 148                 *seq = 0;
 149                 return 0;
 150         default:
 151                 return 1;
 152         }
 153
 154         if (!pskb_may_pull(skb, hlen))
 155                 return -EINVAL;
 156
 157         *spi = *(__be32 *)(skb_transport_header(skb) + offset);
 158         *seq = *(__be32 *)(skb_transport_header(skb) + offset_seq);
 159         return 0;
 160 }
 161
 162 int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
 163 {
 164         struct xfrm_mode *inner_mode = x->inner_mode;
 165         int err;
 166
 167         err = x->outer_mode->afinfo->extract_input(x, skb);
 168         if (err)
 169                 return err;
 170
 171         if (x->sel.family == AF_UNSPEC) {
 172                 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 173                 if (inner_mode == NULL)
 174                         return -EAFNOSUPPORT;
 175         }
 176
 177         skb->protocol = inner_mode->afinfo->eth_proto;
 178         return inner_mode->input2(x, skb);
 179 }
 180 EXPORT_SYMBOL(xfrm_prepare_input);
 181
 182 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 183 {
 184         struct net *net = dev_net(skb->dev);
 185         int err;
 186         __be32 seq;
 187         __be32 seq_hi;
 188         struct xfrm_state *x = NULL;
 189         xfrm_address_t *daddr;
 190         struct xfrm_mode *inner_mode;
 191         u32 mark = skb->mark;
 192         unsigned int family;
 193         int decaps = 0;
 194         int async = 0;
 195
 196         /* A negative encap_type indicates async resumption. */
 197         if (encap_type < 0) {
 198                 async = 1;
 199                 x = xfrm_input_state(skb);
 200                 seq = XFRM_SKB_CB(skb)->seq.input.low;
 201                 family = x->outer_mode->afinfo->family;
 202                 goto resume;
 203         }
 204
 205         daddr = (xfrm_address_t *)(skb_network_header(skb) +
 206                                    XFRM_SPI_SKB_CB(skb)->daddroff);
 207         family = XFRM_SPI_SKB_CB(skb)->family;
 208
 209         /* if tunnel is present override skb->mark value with tunnel i_key */
 210         if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4) {
 211                 switch (family) {
 212                 case AF_INET:
 213                         mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4->parms.i_key);
 214                         break;
 215                 case AF_INET6:
 216                         mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6->parms.i_key);
 217                         break;
 218                 }
 219         }
 220
 221         /* Allocate new secpath or COW existing one. */
 222         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 223                 struct sec_path *sp;
 224
 225                 sp = secpath_dup(skb->sp);
 226                 if (!sp) {
 227                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
 228                         goto drop;
 229                 }
 230                 if (skb->sp)
 231                         secpath_put(skb->sp);
 232                 skb->sp = sp;
 233         }
 234
 235         seq = 0;
 236         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
 237                 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 238                 goto drop;
 239         }
 240
 241         do {
 242                 if (skb->sp->len == XFRM_MAX_DEPTH) {
 243                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
 244                         goto drop;
 245                 }
 246
 247                 x = xfrm_state_lookup(net, mark, daddr, spi, nexthdr, family);
 248                 if (x == NULL) {
 249                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
 250                         xfrm_audit_state_notfound(skb, family, spi, seq);
 251                         goto drop;
 252                 }
 253
 254                 skb->sp->xvec[skb->sp->len++] = x;
 255
 256                 spin_lock(&x->lock);
 257
 258                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 259                         if (x->km.state == XFRM_STATE_ACQ)
 260                                 XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
 261                         else
 262                                 XFRM_INC_STATS(net,
 263                                                LINUX_MIB_XFRMINSTATEINVALID);
 264                         goto drop_unlock;
 265                 }
 266
 267                 if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
 268                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
 269                         goto drop_unlock;
 270                 }
 271
 272                 if (x->repl->check(x, skb, seq)) {
 273                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 274                         goto drop_unlock;
 275                 }
 276
 277                 if (xfrm_state_check_expire(x)) {
 278                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
 279                         goto drop_unlock;
 280                 }
 281
 282                 spin_unlock(&x->lock);
 283
 284                 if (xfrm_tunnel_check(skb, x, family)) {
 285                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 286                         goto drop;
 287                 }
 288
 289                 seq_hi = htonl(xfrm_replay_seqhi(x, seq));
 290
 291                 XFRM_SKB_CB(skb)->seq.input.low = seq;
 292                 XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;
 293
 294                 skb_dst_force(skb);
 295
 296                 nexthdr = x->type->input(x, skb);
 297
 298                 if (nexthdr == -EINPROGRESS)
 299                         return 0;
 300 resume:
 301                 spin_lock(&x->lock);
 302                 if (nexthdr <= 0) {
 303                         if (nexthdr == -EBADMSG) {
 304                                 xfrm_audit_state_icvfail(x, skb,
 305                                                          x->type->proto);
 306                                 x->stats.integrity_failed++;
 307                         }
 308                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 309                         goto drop_unlock;
 310                 }
 311
 312                 /* only the first xfrm gets the encap type */
 313                 encap_type = 0;
 314
 315                 if (async && x->repl->recheck(x, skb, seq)) {
 316                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 317                         goto drop_unlock;
 318                 }
 319
 320                 x->repl->advance(x, seq);
 321
 322                 x->curlft.bytes += skb->len;
 323                 x->curlft.packets++;
 324
 325                 spin_unlock(&x->lock);
 326
 327                 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
 328
 329                 inner_mode = x->inner_mode;
 330
 331                 if (x->sel.family == AF_UNSPEC) {
 332                         inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 333                         if (inner_mode == NULL)
 334                                 goto drop;
 335                 }
 336
 337                 if (inner_mode->input(x, skb)) {
 338                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 339                         goto drop;
 340                 }
 341
 342                 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 343                         decaps = 1;
 344                         break;
 345                 }
 346
 347                 /*
 348                  * We need the inner address.  However, we only get here for
 349                  * transport mode so the outer address is identical.
 350                  */
 351                 daddr = &x->id.daddr;
 352                 family = x->outer_mode->afinfo->family;
 353
 354                 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
 355                 if (err < 0) {
 356                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 357                         goto drop;
 358                 }
 359         } while (!err);
 360
 361         err = xfrm_rcv_cb(skb, family, x->type->proto, 0);
 362         if (err)
 363                 goto drop;
 364
 365         nf_reset(skb);
 366
 367         if (decaps) {
 368                 skb_dst_drop(skb);
 369                 netif_rx(skb);
 370                 return 0;
 371         } else {
 372                 return x->inner_mode->afinfo->transport_finish(skb, async);
 373         }
 374
 375 drop_unlock:
 376         spin_unlock(&x->lock);
 377 drop:
 378         xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1);
 379         kfree_skb(skb);
 380         return 0;
 381 }
 382 EXPORT_SYMBOL(xfrm_input);
 383
 384 int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
 385 {
 386         return xfrm_input(skb, nexthdr, 0, -1);
 387 }
 388 EXPORT_SYMBOL(xfrm_input_resume);
 389
 390 void __init xfrm_input_init(void)
 391 {
 392         secpath_cachep = kmem_cache_create("secpath_cache",
 393                                            sizeof(struct sec_path),
 394                                            0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
 395                                            NULL);
 396 }