root/net/ipv4/esp4.c

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DEFINITIONS

This source file includes following definitions.
  1. esp_alloc_tmp
  2. esp_tmp_extra
  3. esp_tmp_iv
  4. esp_tmp_req
  5. esp_req_sg
  6. esp_ssg_unref
  7. esp_output_done
  8. esp_restore_header
  9. esp_output_restore_header
  10. esp_output_set_extra
  11. esp_output_done_esn
  12. esp_output_fill_trailer
  13. esp_output_udp_encap
  14. esp_output_head
  15. esp_output_tail
  16. esp_output
  17. esp_remove_trailer
  18. esp_input_done2
  19. esp_input_done
  20. esp_input_restore_header
  21. esp_input_set_header
  22. esp_input_done_esn
  23. esp_input
  24. esp4_err
  25. esp_destroy
  26. esp_init_aead
  27. esp_init_authenc
  28. esp_init_state
  29. esp4_rcv_cb
  30. esp4_init
  31. esp4_fini

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #define pr_fmt(fmt) "IPsec: " fmt
   3 
   4 #include <crypto/aead.h>
   5 #include <crypto/authenc.h>
   6 #include <linux/err.h>
   7 #include <linux/module.h>
   8 #include <net/ip.h>
   9 #include <net/xfrm.h>
  10 #include <net/esp.h>
  11 #include <linux/scatterlist.h>
  12 #include <linux/kernel.h>
  13 #include <linux/pfkeyv2.h>
  14 #include <linux/rtnetlink.h>
  15 #include <linux/slab.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/in6.h>
  18 #include <net/icmp.h>
  19 #include <net/protocol.h>
  20 #include <net/udp.h>
  21 
  22 #include <linux/highmem.h>
  23 
  24 struct esp_skb_cb {
  25         struct xfrm_skb_cb xfrm;
  26         void *tmp;
  27 };
  28 
  29 struct esp_output_extra {
  30         __be32 seqhi;
  31         u32 esphoff;
  32 };
  33 
  34 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
  35 
  36 /*
  37  * Allocate an AEAD request structure with extra space for SG and IV.
  38  *
  39  * For alignment considerations the IV is placed at the front, followed
  40  * by the request and finally the SG list.
  41  *
  42  * TODO: Use spare space in skb for this where possible.
  43  */
  44 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
  45 {
  46         unsigned int len;
  47 
  48         len = extralen;
  49 
  50         len += crypto_aead_ivsize(aead);
  51 
  52         if (len) {
  53                 len += crypto_aead_alignmask(aead) &
  54                        ~(crypto_tfm_ctx_alignment() - 1);
  55                 len = ALIGN(len, crypto_tfm_ctx_alignment());
  56         }
  57 
  58         len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
  59         len = ALIGN(len, __alignof__(struct scatterlist));
  60 
  61         len += sizeof(struct scatterlist) * nfrags;
  62 
  63         return kmalloc(len, GFP_ATOMIC);
  64 }
  65 
  66 static inline void *esp_tmp_extra(void *tmp)
  67 {
  68         return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
  69 }
  70 
  71 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
  72 {
  73         return crypto_aead_ivsize(aead) ?
  74                PTR_ALIGN((u8 *)tmp + extralen,
  75                          crypto_aead_alignmask(aead) + 1) : tmp + extralen;
  76 }
  77 
  78 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
  79 {
  80         struct aead_request *req;
  81 
  82         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
  83                                 crypto_tfm_ctx_alignment());
  84         aead_request_set_tfm(req, aead);
  85         return req;
  86 }
  87 
  88 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
  89                                              struct aead_request *req)
  90 {
  91         return (void *)ALIGN((unsigned long)(req + 1) +
  92                              crypto_aead_reqsize(aead),
  93                              __alignof__(struct scatterlist));
  94 }
  95 
  96 static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
  97 {
  98         struct esp_output_extra *extra = esp_tmp_extra(tmp);
  99         struct crypto_aead *aead = x->data;
 100         int extralen = 0;
 101         u8 *iv;
 102         struct aead_request *req;
 103         struct scatterlist *sg;
 104 
 105         if (x->props.flags & XFRM_STATE_ESN)
 106                 extralen += sizeof(*extra);
 107 
 108         extra = esp_tmp_extra(tmp);
 109         iv = esp_tmp_iv(aead, tmp, extralen);
 110         req = esp_tmp_req(aead, iv);
 111 
 112         /* Unref skb_frag_pages in the src scatterlist if necessary.
 113          * Skip the first sg which comes from skb->data.
 114          */
 115         if (req->src != req->dst)
 116                 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
 117                         put_page(sg_page(sg));
 118 }
 119 
 120 static void esp_output_done(struct crypto_async_request *base, int err)
 121 {
 122         struct sk_buff *skb = base->data;
 123         struct xfrm_offload *xo = xfrm_offload(skb);
 124         void *tmp;
 125         struct xfrm_state *x;
 126 
 127         if (xo && (xo->flags & XFRM_DEV_RESUME)) {
 128                 struct sec_path *sp = skb_sec_path(skb);
 129 
 130                 x = sp->xvec[sp->len - 1];
 131         } else {
 132                 x = skb_dst(skb)->xfrm;
 133         }
 134 
 135         tmp = ESP_SKB_CB(skb)->tmp;
 136         esp_ssg_unref(x, tmp);
 137         kfree(tmp);
 138 
 139         if (xo && (xo->flags & XFRM_DEV_RESUME)) {
 140                 if (err) {
 141                         XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
 142                         kfree_skb(skb);
 143                         return;
 144                 }
 145 
 146                 skb_push(skb, skb->data - skb_mac_header(skb));
 147                 secpath_reset(skb);
 148                 xfrm_dev_resume(skb);
 149         } else {
 150                 xfrm_output_resume(skb, err);
 151         }
 152 }
 153 
 154 /* Move ESP header back into place. */
 155 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
 156 {
 157         struct ip_esp_hdr *esph = (void *)(skb->data + offset);
 158         void *tmp = ESP_SKB_CB(skb)->tmp;
 159         __be32 *seqhi = esp_tmp_extra(tmp);
 160 
 161         esph->seq_no = esph->spi;
 162         esph->spi = *seqhi;
 163 }
 164 
 165 static void esp_output_restore_header(struct sk_buff *skb)
 166 {
 167         void *tmp = ESP_SKB_CB(skb)->tmp;
 168         struct esp_output_extra *extra = esp_tmp_extra(tmp);
 169 
 170         esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
 171                                 sizeof(__be32));
 172 }
 173 
 174 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
 175                                                struct xfrm_state *x,
 176                                                struct ip_esp_hdr *esph,
 177                                                struct esp_output_extra *extra)
 178 {
 179         /* For ESN we move the header forward by 4 bytes to
 180          * accomodate the high bits.  We will move it back after
 181          * encryption.
 182          */
 183         if ((x->props.flags & XFRM_STATE_ESN)) {
 184                 __u32 seqhi;
 185                 struct xfrm_offload *xo = xfrm_offload(skb);
 186 
 187                 if (xo)
 188                         seqhi = xo->seq.hi;
 189                 else
 190                         seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
 191 
 192                 extra->esphoff = (unsigned char *)esph -
 193                                  skb_transport_header(skb);
 194                 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
 195                 extra->seqhi = esph->spi;
 196                 esph->seq_no = htonl(seqhi);
 197         }
 198 
 199         esph->spi = x->id.spi;
 200 
 201         return esph;
 202 }
 203 
 204 static void esp_output_done_esn(struct crypto_async_request *base, int err)
 205 {
 206         struct sk_buff *skb = base->data;
 207 
 208         esp_output_restore_header(skb);
 209         esp_output_done(base, err);
 210 }
 211 
 212 static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
 213 {
 214         /* Fill padding... */
 215         if (tfclen) {
 216                 memset(tail, 0, tfclen);
 217                 tail += tfclen;
 218         }
 219         do {
 220                 int i;
 221                 for (i = 0; i < plen - 2; i++)
 222                         tail[i] = i + 1;
 223         } while (0);
 224         tail[plen - 2] = plen - 2;
 225         tail[plen - 1] = proto;
 226 }
 227 
 228 static int esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
 229 {
 230         int encap_type;
 231         struct udphdr *uh;
 232         __be32 *udpdata32;
 233         __be16 sport, dport;
 234         struct xfrm_encap_tmpl *encap = x->encap;
 235         struct ip_esp_hdr *esph = esp->esph;
 236         unsigned int len;
 237 
 238         spin_lock_bh(&x->lock);
 239         sport = encap->encap_sport;
 240         dport = encap->encap_dport;
 241         encap_type = encap->encap_type;
 242         spin_unlock_bh(&x->lock);
 243 
 244         len = skb->len + esp->tailen - skb_transport_offset(skb);
 245         if (len + sizeof(struct iphdr) >= IP_MAX_MTU)
 246                 return -EMSGSIZE;
 247 
 248         uh = (struct udphdr *)esph;
 249         uh->source = sport;
 250         uh->dest = dport;
 251         uh->len = htons(len);
 252         uh->check = 0;
 253 
 254         switch (encap_type) {
 255         default:
 256         case UDP_ENCAP_ESPINUDP:
 257                 esph = (struct ip_esp_hdr *)(uh + 1);
 258                 break;
 259         case UDP_ENCAP_ESPINUDP_NON_IKE:
 260                 udpdata32 = (__be32 *)(uh + 1);
 261                 udpdata32[0] = udpdata32[1] = 0;
 262                 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
 263                 break;
 264         }
 265 
 266         *skb_mac_header(skb) = IPPROTO_UDP;
 267         esp->esph = esph;
 268 
 269         return 0;
 270 }
 271 
 272 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
 273 {
 274         u8 *tail;
 275         u8 *vaddr;
 276         int nfrags;
 277         int esph_offset;
 278         struct page *page;
 279         struct sk_buff *trailer;
 280         int tailen = esp->tailen;
 281 
 282         /* this is non-NULL only with UDP Encapsulation */
 283         if (x->encap) {
 284                 int err = esp_output_udp_encap(x, skb, esp);
 285 
 286                 if (err < 0)
 287                         return err;
 288         }
 289 
 290         if (!skb_cloned(skb)) {
 291                 if (tailen <= skb_tailroom(skb)) {
 292                         nfrags = 1;
 293                         trailer = skb;
 294                         tail = skb_tail_pointer(trailer);
 295 
 296                         goto skip_cow;
 297                 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
 298                            && !skb_has_frag_list(skb)) {
 299                         int allocsize;
 300                         struct sock *sk = skb->sk;
 301                         struct page_frag *pfrag = &x->xfrag;
 302 
 303                         esp->inplace = false;
 304 
 305                         allocsize = ALIGN(tailen, L1_CACHE_BYTES);
 306 
 307                         spin_lock_bh(&x->lock);
 308 
 309                         if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
 310                                 spin_unlock_bh(&x->lock);
 311                                 goto cow;
 312                         }
 313 
 314                         page = pfrag->page;
 315                         get_page(page);
 316 
 317                         vaddr = kmap_atomic(page);
 318 
 319                         tail = vaddr + pfrag->offset;
 320 
 321                         esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
 322 
 323                         kunmap_atomic(vaddr);
 324 
 325                         nfrags = skb_shinfo(skb)->nr_frags;
 326 
 327                         __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
 328                                              tailen);
 329                         skb_shinfo(skb)->nr_frags = ++nfrags;
 330 
 331                         pfrag->offset = pfrag->offset + allocsize;
 332 
 333                         spin_unlock_bh(&x->lock);
 334 
 335                         nfrags++;
 336 
 337                         skb->len += tailen;
 338                         skb->data_len += tailen;
 339                         skb->truesize += tailen;
 340                         if (sk && sk_fullsock(sk))
 341                                 refcount_add(tailen, &sk->sk_wmem_alloc);
 342 
 343                         goto out;
 344                 }
 345         }
 346 
 347 cow:
 348         esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
 349 
 350         nfrags = skb_cow_data(skb, tailen, &trailer);
 351         if (nfrags < 0)
 352                 goto out;
 353         tail = skb_tail_pointer(trailer);
 354         esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
 355 
 356 skip_cow:
 357         esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
 358         pskb_put(skb, trailer, tailen);
 359 
 360 out:
 361         return nfrags;
 362 }
 363 EXPORT_SYMBOL_GPL(esp_output_head);
 364 
 365 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
 366 {
 367         u8 *iv;
 368         int alen;
 369         void *tmp;
 370         int ivlen;
 371         int assoclen;
 372         int extralen;
 373         struct page *page;
 374         struct ip_esp_hdr *esph;
 375         struct crypto_aead *aead;
 376         struct aead_request *req;
 377         struct scatterlist *sg, *dsg;
 378         struct esp_output_extra *extra;
 379         int err = -ENOMEM;
 380 
 381         assoclen = sizeof(struct ip_esp_hdr);
 382         extralen = 0;
 383 
 384         if (x->props.flags & XFRM_STATE_ESN) {
 385                 extralen += sizeof(*extra);
 386                 assoclen += sizeof(__be32);
 387         }
 388 
 389         aead = x->data;
 390         alen = crypto_aead_authsize(aead);
 391         ivlen = crypto_aead_ivsize(aead);
 392 
 393         tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
 394         if (!tmp)
 395                 goto error;
 396 
 397         extra = esp_tmp_extra(tmp);
 398         iv = esp_tmp_iv(aead, tmp, extralen);
 399         req = esp_tmp_req(aead, iv);
 400         sg = esp_req_sg(aead, req);
 401 
 402         if (esp->inplace)
 403                 dsg = sg;
 404         else
 405                 dsg = &sg[esp->nfrags];
 406 
 407         esph = esp_output_set_extra(skb, x, esp->esph, extra);
 408         esp->esph = esph;
 409 
 410         sg_init_table(sg, esp->nfrags);
 411         err = skb_to_sgvec(skb, sg,
 412                            (unsigned char *)esph - skb->data,
 413                            assoclen + ivlen + esp->clen + alen);
 414         if (unlikely(err < 0))
 415                 goto error_free;
 416 
 417         if (!esp->inplace) {
 418                 int allocsize;
 419                 struct page_frag *pfrag = &x->xfrag;
 420 
 421                 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
 422 
 423                 spin_lock_bh(&x->lock);
 424                 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
 425                         spin_unlock_bh(&x->lock);
 426                         goto error_free;
 427                 }
 428 
 429                 skb_shinfo(skb)->nr_frags = 1;
 430 
 431                 page = pfrag->page;
 432                 get_page(page);
 433                 /* replace page frags in skb with new page */
 434                 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
 435                 pfrag->offset = pfrag->offset + allocsize;
 436                 spin_unlock_bh(&x->lock);
 437 
 438                 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
 439                 err = skb_to_sgvec(skb, dsg,
 440                                    (unsigned char *)esph - skb->data,
 441                                    assoclen + ivlen + esp->clen + alen);
 442                 if (unlikely(err < 0))
 443                         goto error_free;
 444         }
 445 
 446         if ((x->props.flags & XFRM_STATE_ESN))
 447                 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
 448         else
 449                 aead_request_set_callback(req, 0, esp_output_done, skb);
 450 
 451         aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
 452         aead_request_set_ad(req, assoclen);
 453 
 454         memset(iv, 0, ivlen);
 455         memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
 456                min(ivlen, 8));
 457 
 458         ESP_SKB_CB(skb)->tmp = tmp;
 459         err = crypto_aead_encrypt(req);
 460 
 461         switch (err) {
 462         case -EINPROGRESS:
 463                 goto error;
 464 
 465         case -ENOSPC:
 466                 err = NET_XMIT_DROP;
 467                 break;
 468 
 469         case 0:
 470                 if ((x->props.flags & XFRM_STATE_ESN))
 471                         esp_output_restore_header(skb);
 472         }
 473 
 474         if (sg != dsg)
 475                 esp_ssg_unref(x, tmp);
 476 
 477 error_free:
 478         kfree(tmp);
 479 error:
 480         return err;
 481 }
 482 EXPORT_SYMBOL_GPL(esp_output_tail);
 483 
 484 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
 485 {
 486         int alen;
 487         int blksize;
 488         struct ip_esp_hdr *esph;
 489         struct crypto_aead *aead;
 490         struct esp_info esp;
 491 
 492         esp.inplace = true;
 493 
 494         esp.proto = *skb_mac_header(skb);
 495         *skb_mac_header(skb) = IPPROTO_ESP;
 496 
 497         /* skb is pure payload to encrypt */
 498 
 499         aead = x->data;
 500         alen = crypto_aead_authsize(aead);
 501 
 502         esp.tfclen = 0;
 503         if (x->tfcpad) {
 504                 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
 505                 u32 padto;
 506 
 507                 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
 508                 if (skb->len < padto)
 509                         esp.tfclen = padto - skb->len;
 510         }
 511         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 512         esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
 513         esp.plen = esp.clen - skb->len - esp.tfclen;
 514         esp.tailen = esp.tfclen + esp.plen + alen;
 515 
 516         esp.esph = ip_esp_hdr(skb);
 517 
 518         esp.nfrags = esp_output_head(x, skb, &esp);
 519         if (esp.nfrags < 0)
 520                 return esp.nfrags;
 521 
 522         esph = esp.esph;
 523         esph->spi = x->id.spi;
 524 
 525         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 526         esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
 527                                  ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
 528 
 529         skb_push(skb, -skb_network_offset(skb));
 530 
 531         return esp_output_tail(x, skb, &esp);
 532 }
 533 
 534 static inline int esp_remove_trailer(struct sk_buff *skb)
 535 {
 536         struct xfrm_state *x = xfrm_input_state(skb);
 537         struct xfrm_offload *xo = xfrm_offload(skb);
 538         struct crypto_aead *aead = x->data;
 539         int alen, hlen, elen;
 540         int padlen, trimlen;
 541         __wsum csumdiff;
 542         u8 nexthdr[2];
 543         int ret;
 544 
 545         alen = crypto_aead_authsize(aead);
 546         hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 547         elen = skb->len - hlen;
 548 
 549         if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
 550                 ret = xo->proto;
 551                 goto out;
 552         }
 553 
 554         if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
 555                 BUG();
 556 
 557         ret = -EINVAL;
 558         padlen = nexthdr[0];
 559         if (padlen + 2 + alen >= elen) {
 560                 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
 561                                     padlen + 2, elen - alen);
 562                 goto out;
 563         }
 564 
 565         trimlen = alen + padlen + 2;
 566         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 567                 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
 568                 skb->csum = csum_block_sub(skb->csum, csumdiff,
 569                                            skb->len - trimlen);
 570         }
 571         pskb_trim(skb, skb->len - trimlen);
 572 
 573         ret = nexthdr[1];
 574 
 575 out:
 576         return ret;
 577 }
 578 
 579 int esp_input_done2(struct sk_buff *skb, int err)
 580 {
 581         const struct iphdr *iph;
 582         struct xfrm_state *x = xfrm_input_state(skb);
 583         struct xfrm_offload *xo = xfrm_offload(skb);
 584         struct crypto_aead *aead = x->data;
 585         int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 586         int ihl;
 587 
 588         if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
 589                 kfree(ESP_SKB_CB(skb)->tmp);
 590 
 591         if (unlikely(err))
 592                 goto out;
 593 
 594         err = esp_remove_trailer(skb);
 595         if (unlikely(err < 0))
 596                 goto out;
 597 
 598         iph = ip_hdr(skb);
 599         ihl = iph->ihl * 4;
 600 
 601         if (x->encap) {
 602                 struct xfrm_encap_tmpl *encap = x->encap;
 603                 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
 604 
 605                 /*
 606                  * 1) if the NAT-T peer's IP or port changed then
 607                  *    advertize the change to the keying daemon.
 608                  *    This is an inbound SA, so just compare
 609                  *    SRC ports.
 610                  */
 611                 if (iph->saddr != x->props.saddr.a4 ||
 612                     uh->source != encap->encap_sport) {
 613                         xfrm_address_t ipaddr;
 614 
 615                         ipaddr.a4 = iph->saddr;
 616                         km_new_mapping(x, &ipaddr, uh->source);
 617 
 618                         /* XXX: perhaps add an extra
 619                          * policy check here, to see
 620                          * if we should allow or
 621                          * reject a packet from a
 622                          * different source
 623                          * address/port.
 624                          */
 625                 }
 626 
 627                 /*
 628                  * 2) ignore UDP/TCP checksums in case
 629                  *    of NAT-T in Transport Mode, or
 630                  *    perform other post-processing fixes
 631                  *    as per draft-ietf-ipsec-udp-encaps-06,
 632                  *    section 3.1.2
 633                  */
 634                 if (x->props.mode == XFRM_MODE_TRANSPORT)
 635                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 636         }
 637 
 638         skb_pull_rcsum(skb, hlen);
 639         if (x->props.mode == XFRM_MODE_TUNNEL)
 640                 skb_reset_transport_header(skb);
 641         else
 642                 skb_set_transport_header(skb, -ihl);
 643 
 644         /* RFC4303: Drop dummy packets without any error */
 645         if (err == IPPROTO_NONE)
 646                 err = -EINVAL;
 647 
 648 out:
 649         return err;
 650 }
 651 EXPORT_SYMBOL_GPL(esp_input_done2);
 652 
 653 static void esp_input_done(struct crypto_async_request *base, int err)
 654 {
 655         struct sk_buff *skb = base->data;
 656 
 657         xfrm_input_resume(skb, esp_input_done2(skb, err));
 658 }
 659 
 660 static void esp_input_restore_header(struct sk_buff *skb)
 661 {
 662         esp_restore_header(skb, 0);
 663         __skb_pull(skb, 4);
 664 }
 665 
 666 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
 667 {
 668         struct xfrm_state *x = xfrm_input_state(skb);
 669         struct ip_esp_hdr *esph;
 670 
 671         /* For ESN we move the header forward by 4 bytes to
 672          * accomodate the high bits.  We will move it back after
 673          * decryption.
 674          */
 675         if ((x->props.flags & XFRM_STATE_ESN)) {
 676                 esph = skb_push(skb, 4);
 677                 *seqhi = esph->spi;
 678                 esph->spi = esph->seq_no;
 679                 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
 680         }
 681 }
 682 
 683 static void esp_input_done_esn(struct crypto_async_request *base, int err)
 684 {
 685         struct sk_buff *skb = base->data;
 686 
 687         esp_input_restore_header(skb);
 688         esp_input_done(base, err);
 689 }
 690 
 691 /*
 692  * Note: detecting truncated vs. non-truncated authentication data is very
 693  * expensive, so we only support truncated data, which is the recommended
 694  * and common case.
 695  */
 696 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
 697 {
 698         struct crypto_aead *aead = x->data;
 699         struct aead_request *req;
 700         struct sk_buff *trailer;
 701         int ivlen = crypto_aead_ivsize(aead);
 702         int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
 703         int nfrags;
 704         int assoclen;
 705         int seqhilen;
 706         __be32 *seqhi;
 707         void *tmp;
 708         u8 *iv;
 709         struct scatterlist *sg;
 710         int err = -EINVAL;
 711 
 712         if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
 713                 goto out;
 714 
 715         if (elen <= 0)
 716                 goto out;
 717 
 718         assoclen = sizeof(struct ip_esp_hdr);
 719         seqhilen = 0;
 720 
 721         if (x->props.flags & XFRM_STATE_ESN) {
 722                 seqhilen += sizeof(__be32);
 723                 assoclen += seqhilen;
 724         }
 725 
 726         if (!skb_cloned(skb)) {
 727                 if (!skb_is_nonlinear(skb)) {
 728                         nfrags = 1;
 729 
 730                         goto skip_cow;
 731                 } else if (!skb_has_frag_list(skb)) {
 732                         nfrags = skb_shinfo(skb)->nr_frags;
 733                         nfrags++;
 734 
 735                         goto skip_cow;
 736                 }
 737         }
 738 
 739         err = skb_cow_data(skb, 0, &trailer);
 740         if (err < 0)
 741                 goto out;
 742 
 743         nfrags = err;
 744 
 745 skip_cow:
 746         err = -ENOMEM;
 747         tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
 748         if (!tmp)
 749                 goto out;
 750 
 751         ESP_SKB_CB(skb)->tmp = tmp;
 752         seqhi = esp_tmp_extra(tmp);
 753         iv = esp_tmp_iv(aead, tmp, seqhilen);
 754         req = esp_tmp_req(aead, iv);
 755         sg = esp_req_sg(aead, req);
 756 
 757         esp_input_set_header(skb, seqhi);
 758 
 759         sg_init_table(sg, nfrags);
 760         err = skb_to_sgvec(skb, sg, 0, skb->len);
 761         if (unlikely(err < 0)) {
 762                 kfree(tmp);
 763                 goto out;
 764         }
 765 
 766         skb->ip_summed = CHECKSUM_NONE;
 767 
 768         if ((x->props.flags & XFRM_STATE_ESN))
 769                 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
 770         else
 771                 aead_request_set_callback(req, 0, esp_input_done, skb);
 772 
 773         aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
 774         aead_request_set_ad(req, assoclen);
 775 
 776         err = crypto_aead_decrypt(req);
 777         if (err == -EINPROGRESS)
 778                 goto out;
 779 
 780         if ((x->props.flags & XFRM_STATE_ESN))
 781                 esp_input_restore_header(skb);
 782 
 783         err = esp_input_done2(skb, err);
 784 
 785 out:
 786         return err;
 787 }
 788 
 789 static int esp4_err(struct sk_buff *skb, u32 info)
 790 {
 791         struct net *net = dev_net(skb->dev);
 792         const struct iphdr *iph = (const struct iphdr *)skb->data;
 793         struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
 794         struct xfrm_state *x;
 795 
 796         switch (icmp_hdr(skb)->type) {
 797         case ICMP_DEST_UNREACH:
 798                 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
 799                         return 0;
 800         case ICMP_REDIRECT:
 801                 break;
 802         default:
 803                 return 0;
 804         }
 805 
 806         x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
 807                               esph->spi, IPPROTO_ESP, AF_INET);
 808         if (!x)
 809                 return 0;
 810 
 811         if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
 812                 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
 813         else
 814                 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
 815         xfrm_state_put(x);
 816 
 817         return 0;
 818 }
 819 
 820 static void esp_destroy(struct xfrm_state *x)
 821 {
 822         struct crypto_aead *aead = x->data;
 823 
 824         if (!aead)
 825                 return;
 826 
 827         crypto_free_aead(aead);
 828 }
 829 
 830 static int esp_init_aead(struct xfrm_state *x)
 831 {
 832         char aead_name[CRYPTO_MAX_ALG_NAME];
 833         struct crypto_aead *aead;
 834         int err;
 835 
 836         err = -ENAMETOOLONG;
 837         if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
 838                      x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
 839                 goto error;
 840 
 841         aead = crypto_alloc_aead(aead_name, 0, 0);
 842         err = PTR_ERR(aead);
 843         if (IS_ERR(aead))
 844                 goto error;
 845 
 846         x->data = aead;
 847 
 848         err = crypto_aead_setkey(aead, x->aead->alg_key,
 849                                  (x->aead->alg_key_len + 7) / 8);
 850         if (err)
 851                 goto error;
 852 
 853         err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
 854         if (err)
 855                 goto error;
 856 
 857 error:
 858         return err;
 859 }
 860 
 861 static int esp_init_authenc(struct xfrm_state *x)
 862 {
 863         struct crypto_aead *aead;
 864         struct crypto_authenc_key_param *param;
 865         struct rtattr *rta;
 866         char *key;
 867         char *p;
 868         char authenc_name[CRYPTO_MAX_ALG_NAME];
 869         unsigned int keylen;
 870         int err;
 871 
 872         err = -EINVAL;
 873         if (!x->ealg)
 874                 goto error;
 875 
 876         err = -ENAMETOOLONG;
 877 
 878         if ((x->props.flags & XFRM_STATE_ESN)) {
 879                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 880                              "%s%sauthencesn(%s,%s)%s",
 881                              x->geniv ?: "", x->geniv ? "(" : "",
 882                              x->aalg ? x->aalg->alg_name : "digest_null",
 883                              x->ealg->alg_name,
 884                              x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
 885                         goto error;
 886         } else {
 887                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 888                              "%s%sauthenc(%s,%s)%s",
 889                              x->geniv ?: "", x->geniv ? "(" : "",
 890                              x->aalg ? x->aalg->alg_name : "digest_null",
 891                              x->ealg->alg_name,
 892                              x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
 893                         goto error;
 894         }
 895 
 896         aead = crypto_alloc_aead(authenc_name, 0, 0);
 897         err = PTR_ERR(aead);
 898         if (IS_ERR(aead))
 899                 goto error;
 900 
 901         x->data = aead;
 902 
 903         keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
 904                  (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
 905         err = -ENOMEM;
 906         key = kmalloc(keylen, GFP_KERNEL);
 907         if (!key)
 908                 goto error;
 909 
 910         p = key;
 911         rta = (void *)p;
 912         rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
 913         rta->rta_len = RTA_LENGTH(sizeof(*param));
 914         param = RTA_DATA(rta);
 915         p += RTA_SPACE(sizeof(*param));
 916 
 917         if (x->aalg) {
 918                 struct xfrm_algo_desc *aalg_desc;
 919 
 920                 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
 921                 p += (x->aalg->alg_key_len + 7) / 8;
 922 
 923                 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
 924                 BUG_ON(!aalg_desc);
 925 
 926                 err = -EINVAL;
 927                 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
 928                     crypto_aead_authsize(aead)) {
 929                         pr_info("ESP: %s digestsize %u != %hu\n",
 930                                 x->aalg->alg_name,
 931                                 crypto_aead_authsize(aead),
 932                                 aalg_desc->uinfo.auth.icv_fullbits / 8);
 933                         goto free_key;
 934                 }
 935 
 936                 err = crypto_aead_setauthsize(
 937                         aead, x->aalg->alg_trunc_len / 8);
 938                 if (err)
 939                         goto free_key;
 940         }
 941 
 942         param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
 943         memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
 944 
 945         err = crypto_aead_setkey(aead, key, keylen);
 946 
 947 free_key:
 948         kfree(key);
 949 
 950 error:
 951         return err;
 952 }
 953 
 954 static int esp_init_state(struct xfrm_state *x)
 955 {
 956         struct crypto_aead *aead;
 957         u32 align;
 958         int err;
 959 
 960         x->data = NULL;
 961 
 962         if (x->aead)
 963                 err = esp_init_aead(x);
 964         else
 965                 err = esp_init_authenc(x);
 966 
 967         if (err)
 968                 goto error;
 969 
 970         aead = x->data;
 971 
 972         x->props.header_len = sizeof(struct ip_esp_hdr) +
 973                               crypto_aead_ivsize(aead);
 974         if (x->props.mode == XFRM_MODE_TUNNEL)
 975                 x->props.header_len += sizeof(struct iphdr);
 976         else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
 977                 x->props.header_len += IPV4_BEET_PHMAXLEN;
 978         if (x->encap) {
 979                 struct xfrm_encap_tmpl *encap = x->encap;
 980 
 981                 switch (encap->encap_type) {
 982                 default:
 983                         err = -EINVAL;
 984                         goto error;
 985                 case UDP_ENCAP_ESPINUDP:
 986                         x->props.header_len += sizeof(struct udphdr);
 987                         break;
 988                 case UDP_ENCAP_ESPINUDP_NON_IKE:
 989                         x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
 990                         break;
 991                 }
 992         }
 993 
 994         align = ALIGN(crypto_aead_blocksize(aead), 4);
 995         x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
 996 
 997 error:
 998         return err;
 999 }
1000 
1001 static int esp4_rcv_cb(struct sk_buff *skb, int err)
1002 {
1003         return 0;
1004 }
1005 
1006 static const struct xfrm_type esp_type =
1007 {
1008         .description    = "ESP4",
1009         .owner          = THIS_MODULE,
1010         .proto          = IPPROTO_ESP,
1011         .flags          = XFRM_TYPE_REPLAY_PROT,
1012         .init_state     = esp_init_state,
1013         .destructor     = esp_destroy,
1014         .input          = esp_input,
1015         .output         = esp_output,
1016 };
1017 
1018 static struct xfrm4_protocol esp4_protocol = {
1019         .handler        =       xfrm4_rcv,
1020         .input_handler  =       xfrm_input,
1021         .cb_handler     =       esp4_rcv_cb,
1022         .err_handler    =       esp4_err,
1023         .priority       =       0,
1024 };
1025 
1026 static int __init esp4_init(void)
1027 {
1028         if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1029                 pr_info("%s: can't add xfrm type\n", __func__);
1030                 return -EAGAIN;
1031         }
1032         if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1033                 pr_info("%s: can't add protocol\n", __func__);
1034                 xfrm_unregister_type(&esp_type, AF_INET);
1035                 return -EAGAIN;
1036         }
1037         return 0;
1038 }
1039 
1040 static void __exit esp4_fini(void)
1041 {
1042         if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1043                 pr_info("%s: can't remove protocol\n", __func__);
1044         xfrm_unregister_type(&esp_type, AF_INET);
1045 }
1046 
1047 module_init(esp4_init);
1048 module_exit(esp4_fini);
1049 MODULE_LICENSE("GPL");
1050 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);

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