1 #define pr_fmt(fmt) "IPsec: " fmt 2 3 #include <crypto/aead.h> 4 #include <crypto/authenc.h> 5 #include <linux/err.h> 6 #include <linux/module.h> 7 #include <net/ip.h> 8 #include <net/xfrm.h> 9 #include <net/esp.h> 10 #include <linux/scatterlist.h> 11 #include <linux/kernel.h> 12 #include <linux/pfkeyv2.h> 13 #include <linux/rtnetlink.h> 14 #include <linux/slab.h> 15 #include <linux/spinlock.h> 16 #include <linux/in6.h> 17 #include <net/icmp.h> 18 #include <net/protocol.h> 19 #include <net/udp.h> 20 21 #include <linux/highmem.h> 22 23 struct esp_skb_cb { 24 struct xfrm_skb_cb xfrm; 25 void *tmp; 26 }; 27 28 struct esp_output_extra { 29 __be32 seqhi; 30 u32 esphoff; 31 }; 32 33 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 34 35 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu); 36 37 /* 38 * Allocate an AEAD request structure with extra space for SG and IV. 39 * 40 * For alignment considerations the IV is placed at the front, followed 41 * by the request and finally the SG list. 42 * 43 * TODO: Use spare space in skb for this where possible. 44 */ 45 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen) 46 { 47 unsigned int len; 48 49 len = extralen; 50 51 len += crypto_aead_ivsize(aead); 52 53 if (len) { 54 len += crypto_aead_alignmask(aead) & 55 ~(crypto_tfm_ctx_alignment() - 1); 56 len = ALIGN(len, crypto_tfm_ctx_alignment()); 57 } 58 59 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 60 len = ALIGN(len, __alignof__(struct scatterlist)); 61 62 len += sizeof(struct scatterlist) * nfrags; 63 64 return kmalloc(len, GFP_ATOMIC); 65 } 66 67 static inline void *esp_tmp_extra(void *tmp) 68 { 69 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 70 } 71 72 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen) 73 { 74 return crypto_aead_ivsize(aead) ? 75 PTR_ALIGN((u8 *)tmp + extralen, 76 crypto_aead_alignmask(aead) + 1) : tmp + extralen; 77 } 78 79 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 80 { 81 struct aead_request *req; 82 83 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 84 crypto_tfm_ctx_alignment()); 85 aead_request_set_tfm(req, aead); 86 return req; 87 } 88 89 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 90 struct aead_request *req) 91 { 92 return (void *)ALIGN((unsigned long)(req + 1) + 93 crypto_aead_reqsize(aead), 94 __alignof__(struct scatterlist)); 95 } 96 97 static void esp_ssg_unref(struct xfrm_state *x, void *tmp) 98 { 99 struct esp_output_extra *extra = esp_tmp_extra(tmp); 100 struct crypto_aead *aead = x->data; 101 int extralen = 0; 102 u8 *iv; 103 struct aead_request *req; 104 struct scatterlist *sg; 105 106 if (x->props.flags & XFRM_STATE_ESN) 107 extralen += sizeof(*extra); 108 109 extra = esp_tmp_extra(tmp); 110 iv = esp_tmp_iv(aead, tmp, extralen); 111 req = esp_tmp_req(aead, iv); 112 113 /* Unref skb_frag_pages in the src scatterlist if necessary. 114 * Skip the first sg which comes from skb->data. 115 */ 116 if (req->src != req->dst) 117 for (sg = sg_next(req->src); sg; sg = sg_next(sg)) 118 put_page(sg_page(sg)); 119 } 120 121 static void esp_output_done(struct crypto_async_request *base, int err) 122 { 123 struct sk_buff *skb = base->data; 124 void *tmp; 125 struct dst_entry *dst = skb_dst(skb); 126 struct xfrm_state *x = dst->xfrm; 127 128 tmp = ESP_SKB_CB(skb)->tmp; 129 esp_ssg_unref(x, tmp); 130 kfree(tmp); 131 xfrm_output_resume(skb, err); 132 } 133 134 /* Move ESP header back into place. */ 135 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 136 { 137 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 138 void *tmp = ESP_SKB_CB(skb)->tmp; 139 __be32 *seqhi = esp_tmp_extra(tmp); 140 141 esph->seq_no = esph->spi; 142 esph->spi = *seqhi; 143 } 144 145 static void esp_output_restore_header(struct sk_buff *skb) 146 { 147 void *tmp = ESP_SKB_CB(skb)->tmp; 148 struct esp_output_extra *extra = esp_tmp_extra(tmp); 149 150 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 151 sizeof(__be32)); 152 } 153 154 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 155 struct xfrm_state *x, 156 struct ip_esp_hdr *esph, 157 struct esp_output_extra *extra) 158 { 159 /* For ESN we move the header forward by 4 bytes to 160 * accomodate the high bits. We will move it back after 161 * encryption. 162 */ 163 if ((x->props.flags & XFRM_STATE_ESN)) { 164 __u32 seqhi; 165 struct xfrm_offload *xo = xfrm_offload(skb); 166 167 if (xo) 168 seqhi = xo->seq.hi; 169 else 170 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 171 172 extra->esphoff = (unsigned char *)esph - 173 skb_transport_header(skb); 174 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 175 extra->seqhi = esph->spi; 176 esph->seq_no = htonl(seqhi); 177 } 178 179 esph->spi = x->id.spi; 180 181 return esph; 182 } 183 184 static void esp_output_done_esn(struct crypto_async_request *base, int err) 185 { 186 struct sk_buff *skb = base->data; 187 188 esp_output_restore_header(skb); 189 esp_output_done(base, err); 190 } 191 192 static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto) 193 { 194 /* Fill padding... */ 195 if (tfclen) { 196 memset(tail, 0, tfclen); 197 tail += tfclen; 198 } 199 do { 200 int i; 201 for (i = 0; i < plen - 2; i++) 202 tail[i] = i + 1; 203 } while (0); 204 tail[plen - 2] = plen - 2; 205 tail[plen - 1] = proto; 206 } 207 208 static void esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 209 { 210 int encap_type; 211 struct udphdr *uh; 212 __be32 *udpdata32; 213 __be16 sport, dport; 214 struct xfrm_encap_tmpl *encap = x->encap; 215 struct ip_esp_hdr *esph = esp->esph; 216 217 spin_lock_bh(&x->lock); 218 sport = encap->encap_sport; 219 dport = encap->encap_dport; 220 encap_type = encap->encap_type; 221 spin_unlock_bh(&x->lock); 222 223 uh = (struct udphdr *)esph; 224 uh->source = sport; 225 uh->dest = dport; 226 uh->len = htons(skb->len + esp->tailen 227 - skb_transport_offset(skb)); 228 uh->check = 0; 229 230 switch (encap_type) { 231 default: 232 case UDP_ENCAP_ESPINUDP: 233 esph = (struct ip_esp_hdr *)(uh + 1); 234 break; 235 case UDP_ENCAP_ESPINUDP_NON_IKE: 236 udpdata32 = (__be32 *)(uh + 1); 237 udpdata32[0] = udpdata32[1] = 0; 238 esph = (struct ip_esp_hdr *)(udpdata32 + 2); 239 break; 240 } 241 242 *skb_mac_header(skb) = IPPROTO_UDP; 243 esp->esph = esph; 244 } 245 246 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 247 { 248 u8 *tail; 249 u8 *vaddr; 250 int nfrags; 251 struct page *page; 252 struct sk_buff *trailer; 253 int tailen = esp->tailen; 254 255 /* this is non-NULL only with UDP Encapsulation */ 256 if (x->encap) 257 esp_output_udp_encap(x, skb, esp); 258 259 if (!skb_cloned(skb)) { 260 if (tailen <= skb_availroom(skb)) { 261 nfrags = 1; 262 trailer = skb; 263 tail = skb_tail_pointer(trailer); 264 265 goto skip_cow; 266 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 267 && !skb_has_frag_list(skb)) { 268 int allocsize; 269 struct sock *sk = skb->sk; 270 struct page_frag *pfrag = &x->xfrag; 271 272 esp->inplace = false; 273 274 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 275 276 spin_lock_bh(&x->lock); 277 278 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 279 spin_unlock_bh(&x->lock); 280 goto cow; 281 } 282 283 page = pfrag->page; 284 get_page(page); 285 286 vaddr = kmap_atomic(page); 287 288 tail = vaddr + pfrag->offset; 289 290 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 291 292 kunmap_atomic(vaddr); 293 294 spin_unlock_bh(&x->lock); 295 296 nfrags = skb_shinfo(skb)->nr_frags; 297 298 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 299 tailen); 300 skb_shinfo(skb)->nr_frags = ++nfrags; 301 302 pfrag->offset = pfrag->offset + allocsize; 303 nfrags++; 304 305 skb->len += tailen; 306 skb->data_len += tailen; 307 skb->truesize += tailen; 308 if (sk) 309 atomic_add(tailen, &sk->sk_wmem_alloc); 310 311 goto out; 312 } 313 } 314 315 cow: 316 nfrags = skb_cow_data(skb, tailen, &trailer); 317 if (nfrags < 0) 318 goto out; 319 tail = skb_tail_pointer(trailer); 320 esp->esph = ip_esp_hdr(skb); 321 322 skip_cow: 323 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 324 pskb_put(skb, trailer, tailen); 325 326 out: 327 return nfrags; 328 } 329 EXPORT_SYMBOL_GPL(esp_output_head); 330 331 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 332 { 333 u8 *iv; 334 int alen; 335 void *tmp; 336 int ivlen; 337 int assoclen; 338 int extralen; 339 struct page *page; 340 struct ip_esp_hdr *esph; 341 struct crypto_aead *aead; 342 struct aead_request *req; 343 struct scatterlist *sg, *dsg; 344 struct esp_output_extra *extra; 345 int err = -ENOMEM; 346 347 assoclen = sizeof(struct ip_esp_hdr); 348 extralen = 0; 349 350 if (x->props.flags & XFRM_STATE_ESN) { 351 extralen += sizeof(*extra); 352 assoclen += sizeof(__be32); 353 } 354 355 aead = x->data; 356 alen = crypto_aead_authsize(aead); 357 ivlen = crypto_aead_ivsize(aead); 358 359 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 360 if (!tmp) 361 goto error; 362 363 extra = esp_tmp_extra(tmp); 364 iv = esp_tmp_iv(aead, tmp, extralen); 365 req = esp_tmp_req(aead, iv); 366 sg = esp_req_sg(aead, req); 367 368 if (esp->inplace) 369 dsg = sg; 370 else 371 dsg = &sg[esp->nfrags]; 372 373 esph = esp_output_set_extra(skb, x, esp->esph, extra); 374 esp->esph = esph; 375 376 sg_init_table(sg, esp->nfrags); 377 skb_to_sgvec(skb, sg, 378 (unsigned char *)esph - skb->data, 379 assoclen + ivlen + esp->clen + alen); 380 381 if (!esp->inplace) { 382 int allocsize; 383 struct page_frag *pfrag = &x->xfrag; 384 385 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 386 387 spin_lock_bh(&x->lock); 388 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 389 spin_unlock_bh(&x->lock); 390 goto error; 391 } 392 393 skb_shinfo(skb)->nr_frags = 1; 394 395 page = pfrag->page; 396 get_page(page); 397 /* replace page frags in skb with new page */ 398 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 399 pfrag->offset = pfrag->offset + allocsize; 400 spin_unlock_bh(&x->lock); 401 402 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 403 skb_to_sgvec(skb, dsg, 404 (unsigned char *)esph - skb->data, 405 assoclen + ivlen + esp->clen + alen); 406 } 407 408 if ((x->props.flags & XFRM_STATE_ESN)) 409 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 410 else 411 aead_request_set_callback(req, 0, esp_output_done, skb); 412 413 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 414 aead_request_set_ad(req, assoclen); 415 416 memset(iv, 0, ivlen); 417 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 418 min(ivlen, 8)); 419 420 ESP_SKB_CB(skb)->tmp = tmp; 421 err = crypto_aead_encrypt(req); 422 423 switch (err) { 424 case -EINPROGRESS: 425 goto error; 426 427 case -EBUSY: 428 err = NET_XMIT_DROP; 429 break; 430 431 case 0: 432 if ((x->props.flags & XFRM_STATE_ESN)) 433 esp_output_restore_header(skb); 434 } 435 436 if (sg != dsg) 437 esp_ssg_unref(x, tmp); 438 kfree(tmp); 439 440 error: 441 return err; 442 } 443 EXPORT_SYMBOL_GPL(esp_output_tail); 444 445 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 446 { 447 int alen; 448 int blksize; 449 struct ip_esp_hdr *esph; 450 struct crypto_aead *aead; 451 struct esp_info esp; 452 453 esp.inplace = true; 454 455 esp.proto = *skb_mac_header(skb); 456 *skb_mac_header(skb) = IPPROTO_ESP; 457 458 /* skb is pure payload to encrypt */ 459 460 aead = x->data; 461 alen = crypto_aead_authsize(aead); 462 463 esp.tfclen = 0; 464 if (x->tfcpad) { 465 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 466 u32 padto; 467 468 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached)); 469 if (skb->len < padto) 470 esp.tfclen = padto - skb->len; 471 } 472 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 473 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 474 esp.plen = esp.clen - skb->len - esp.tfclen; 475 esp.tailen = esp.tfclen + esp.plen + alen; 476 477 esp.esph = ip_esp_hdr(skb); 478 479 esp.nfrags = esp_output_head(x, skb, &esp); 480 if (esp.nfrags < 0) 481 return esp.nfrags; 482 483 esph = esp.esph; 484 esph->spi = x->id.spi; 485 486 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 487 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 488 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 489 490 skb_push(skb, -skb_network_offset(skb)); 491 492 return esp_output_tail(x, skb, &esp); 493 } 494 495 int esp_input_done2(struct sk_buff *skb, int err) 496 { 497 const struct iphdr *iph; 498 struct xfrm_state *x = xfrm_input_state(skb); 499 struct xfrm_offload *xo = xfrm_offload(skb); 500 struct crypto_aead *aead = x->data; 501 int alen = crypto_aead_authsize(aead); 502 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 503 int elen = skb->len - hlen; 504 int ihl; 505 u8 nexthdr[2]; 506 int padlen; 507 508 if (!xo || (xo && !(xo->flags & CRYPTO_DONE))) 509 kfree(ESP_SKB_CB(skb)->tmp); 510 511 if (unlikely(err)) 512 goto out; 513 514 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) 515 BUG(); 516 517 err = -EINVAL; 518 padlen = nexthdr[0]; 519 if (padlen + 2 + alen >= elen) 520 goto out; 521 522 /* ... check padding bits here. Silly. :-) */ 523 524 iph = ip_hdr(skb); 525 ihl = iph->ihl * 4; 526 527 if (x->encap) { 528 struct xfrm_encap_tmpl *encap = x->encap; 529 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 530 531 /* 532 * 1) if the NAT-T peer's IP or port changed then 533 * advertize the change to the keying daemon. 534 * This is an inbound SA, so just compare 535 * SRC ports. 536 */ 537 if (iph->saddr != x->props.saddr.a4 || 538 uh->source != encap->encap_sport) { 539 xfrm_address_t ipaddr; 540 541 ipaddr.a4 = iph->saddr; 542 km_new_mapping(x, &ipaddr, uh->source); 543 544 /* XXX: perhaps add an extra 545 * policy check here, to see 546 * if we should allow or 547 * reject a packet from a 548 * different source 549 * address/port. 550 */ 551 } 552 553 /* 554 * 2) ignore UDP/TCP checksums in case 555 * of NAT-T in Transport Mode, or 556 * perform other post-processing fixes 557 * as per draft-ietf-ipsec-udp-encaps-06, 558 * section 3.1.2 559 */ 560 if (x->props.mode == XFRM_MODE_TRANSPORT) 561 skb->ip_summed = CHECKSUM_UNNECESSARY; 562 } 563 564 pskb_trim(skb, skb->len - alen - padlen - 2); 565 __skb_pull(skb, hlen); 566 if (x->props.mode == XFRM_MODE_TUNNEL) 567 skb_reset_transport_header(skb); 568 else 569 skb_set_transport_header(skb, -ihl); 570 571 err = nexthdr[1]; 572 573 /* RFC4303: Drop dummy packets without any error */ 574 if (err == IPPROTO_NONE) 575 err = -EINVAL; 576 577 out: 578 return err; 579 } 580 EXPORT_SYMBOL_GPL(esp_input_done2); 581 582 static void esp_input_done(struct crypto_async_request *base, int err) 583 { 584 struct sk_buff *skb = base->data; 585 586 xfrm_input_resume(skb, esp_input_done2(skb, err)); 587 } 588 589 static void esp_input_restore_header(struct sk_buff *skb) 590 { 591 esp_restore_header(skb, 0); 592 __skb_pull(skb, 4); 593 } 594 595 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 596 { 597 struct xfrm_state *x = xfrm_input_state(skb); 598 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)skb->data; 599 600 /* For ESN we move the header forward by 4 bytes to 601 * accomodate the high bits. We will move it back after 602 * decryption. 603 */ 604 if ((x->props.flags & XFRM_STATE_ESN)) { 605 esph = (void *)skb_push(skb, 4); 606 *seqhi = esph->spi; 607 esph->spi = esph->seq_no; 608 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 609 } 610 } 611 612 static void esp_input_done_esn(struct crypto_async_request *base, int err) 613 { 614 struct sk_buff *skb = base->data; 615 616 esp_input_restore_header(skb); 617 esp_input_done(base, err); 618 } 619 620 /* 621 * Note: detecting truncated vs. non-truncated authentication data is very 622 * expensive, so we only support truncated data, which is the recommended 623 * and common case. 624 */ 625 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 626 { 627 struct ip_esp_hdr *esph; 628 struct crypto_aead *aead = x->data; 629 struct aead_request *req; 630 struct sk_buff *trailer; 631 int ivlen = crypto_aead_ivsize(aead); 632 int elen = skb->len - sizeof(*esph) - ivlen; 633 int nfrags; 634 int assoclen; 635 int seqhilen; 636 __be32 *seqhi; 637 void *tmp; 638 u8 *iv; 639 struct scatterlist *sg; 640 int err = -EINVAL; 641 642 if (!pskb_may_pull(skb, sizeof(*esph) + ivlen)) 643 goto out; 644 645 if (elen <= 0) 646 goto out; 647 648 assoclen = sizeof(*esph); 649 seqhilen = 0; 650 651 if (x->props.flags & XFRM_STATE_ESN) { 652 seqhilen += sizeof(__be32); 653 assoclen += seqhilen; 654 } 655 656 if (!skb_cloned(skb)) { 657 if (!skb_is_nonlinear(skb)) { 658 nfrags = 1; 659 660 goto skip_cow; 661 } else if (!skb_has_frag_list(skb)) { 662 nfrags = skb_shinfo(skb)->nr_frags; 663 nfrags++; 664 665 goto skip_cow; 666 } 667 } 668 669 err = skb_cow_data(skb, 0, &trailer); 670 if (err < 0) 671 goto out; 672 673 nfrags = err; 674 675 skip_cow: 676 err = -ENOMEM; 677 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 678 if (!tmp) 679 goto out; 680 681 ESP_SKB_CB(skb)->tmp = tmp; 682 seqhi = esp_tmp_extra(tmp); 683 iv = esp_tmp_iv(aead, tmp, seqhilen); 684 req = esp_tmp_req(aead, iv); 685 sg = esp_req_sg(aead, req); 686 687 esp_input_set_header(skb, seqhi); 688 689 sg_init_table(sg, nfrags); 690 skb_to_sgvec(skb, sg, 0, skb->len); 691 692 skb->ip_summed = CHECKSUM_NONE; 693 694 if ((x->props.flags & XFRM_STATE_ESN)) 695 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 696 else 697 aead_request_set_callback(req, 0, esp_input_done, skb); 698 699 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 700 aead_request_set_ad(req, assoclen); 701 702 err = crypto_aead_decrypt(req); 703 if (err == -EINPROGRESS) 704 goto out; 705 706 if ((x->props.flags & XFRM_STATE_ESN)) 707 esp_input_restore_header(skb); 708 709 err = esp_input_done2(skb, err); 710 711 out: 712 return err; 713 } 714 715 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu) 716 { 717 struct crypto_aead *aead = x->data; 718 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 719 unsigned int net_adj; 720 721 switch (x->props.mode) { 722 case XFRM_MODE_TRANSPORT: 723 case XFRM_MODE_BEET: 724 net_adj = sizeof(struct iphdr); 725 break; 726 case XFRM_MODE_TUNNEL: 727 net_adj = 0; 728 break; 729 default: 730 BUG(); 731 } 732 733 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) - 734 net_adj) & ~(blksize - 1)) + net_adj - 2; 735 } 736 737 static int esp4_err(struct sk_buff *skb, u32 info) 738 { 739 struct net *net = dev_net(skb->dev); 740 const struct iphdr *iph = (const struct iphdr *)skb->data; 741 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 742 struct xfrm_state *x; 743 744 switch (icmp_hdr(skb)->type) { 745 case ICMP_DEST_UNREACH: 746 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 747 return 0; 748 case ICMP_REDIRECT: 749 break; 750 default: 751 return 0; 752 } 753 754 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 755 esph->spi, IPPROTO_ESP, AF_INET); 756 if (!x) 757 return 0; 758 759 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 760 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0); 761 else 762 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0); 763 xfrm_state_put(x); 764 765 return 0; 766 } 767 768 static void esp_destroy(struct xfrm_state *x) 769 { 770 struct crypto_aead *aead = x->data; 771 772 if (!aead) 773 return; 774 775 crypto_free_aead(aead); 776 } 777 778 static int esp_init_aead(struct xfrm_state *x) 779 { 780 char aead_name[CRYPTO_MAX_ALG_NAME]; 781 struct crypto_aead *aead; 782 int err; 783 u32 mask = 0; 784 785 err = -ENAMETOOLONG; 786 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 787 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 788 goto error; 789 790 if (x->xso.offload_handle) 791 mask |= CRYPTO_ALG_ASYNC; 792 793 aead = crypto_alloc_aead(aead_name, 0, mask); 794 err = PTR_ERR(aead); 795 if (IS_ERR(aead)) 796 goto error; 797 798 x->data = aead; 799 800 err = crypto_aead_setkey(aead, x->aead->alg_key, 801 (x->aead->alg_key_len + 7) / 8); 802 if (err) 803 goto error; 804 805 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 806 if (err) 807 goto error; 808 809 error: 810 return err; 811 } 812 813 static int esp_init_authenc(struct xfrm_state *x) 814 { 815 struct crypto_aead *aead; 816 struct crypto_authenc_key_param *param; 817 struct rtattr *rta; 818 char *key; 819 char *p; 820 char authenc_name[CRYPTO_MAX_ALG_NAME]; 821 unsigned int keylen; 822 int err; 823 u32 mask = 0; 824 825 err = -EINVAL; 826 if (!x->ealg) 827 goto error; 828 829 err = -ENAMETOOLONG; 830 831 if ((x->props.flags & XFRM_STATE_ESN)) { 832 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 833 "%s%sauthencesn(%s,%s)%s", 834 x->geniv ?: "", x->geniv ? "(" : "", 835 x->aalg ? x->aalg->alg_name : "digest_null", 836 x->ealg->alg_name, 837 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 838 goto error; 839 } else { 840 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 841 "%s%sauthenc(%s,%s)%s", 842 x->geniv ?: "", x->geniv ? "(" : "", 843 x->aalg ? x->aalg->alg_name : "digest_null", 844 x->ealg->alg_name, 845 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 846 goto error; 847 } 848 849 if (x->xso.offload_handle) 850 mask |= CRYPTO_ALG_ASYNC; 851 852 aead = crypto_alloc_aead(authenc_name, 0, mask); 853 err = PTR_ERR(aead); 854 if (IS_ERR(aead)) 855 goto error; 856 857 x->data = aead; 858 859 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 860 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 861 err = -ENOMEM; 862 key = kmalloc(keylen, GFP_KERNEL); 863 if (!key) 864 goto error; 865 866 p = key; 867 rta = (void *)p; 868 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 869 rta->rta_len = RTA_LENGTH(sizeof(*param)); 870 param = RTA_DATA(rta); 871 p += RTA_SPACE(sizeof(*param)); 872 873 if (x->aalg) { 874 struct xfrm_algo_desc *aalg_desc; 875 876 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 877 p += (x->aalg->alg_key_len + 7) / 8; 878 879 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 880 BUG_ON(!aalg_desc); 881 882 err = -EINVAL; 883 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 884 crypto_aead_authsize(aead)) { 885 pr_info("ESP: %s digestsize %u != %hu\n", 886 x->aalg->alg_name, 887 crypto_aead_authsize(aead), 888 aalg_desc->uinfo.auth.icv_fullbits / 8); 889 goto free_key; 890 } 891 892 err = crypto_aead_setauthsize( 893 aead, x->aalg->alg_trunc_len / 8); 894 if (err) 895 goto free_key; 896 } 897 898 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 899 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 900 901 err = crypto_aead_setkey(aead, key, keylen); 902 903 free_key: 904 kfree(key); 905 906 error: 907 return err; 908 } 909 910 static int esp_init_state(struct xfrm_state *x) 911 { 912 struct crypto_aead *aead; 913 u32 align; 914 int err; 915 916 x->data = NULL; 917 918 if (x->aead) 919 err = esp_init_aead(x); 920 else 921 err = esp_init_authenc(x); 922 923 if (err) 924 goto error; 925 926 aead = x->data; 927 928 x->props.header_len = sizeof(struct ip_esp_hdr) + 929 crypto_aead_ivsize(aead); 930 if (x->props.mode == XFRM_MODE_TUNNEL) 931 x->props.header_len += sizeof(struct iphdr); 932 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 933 x->props.header_len += IPV4_BEET_PHMAXLEN; 934 if (x->encap) { 935 struct xfrm_encap_tmpl *encap = x->encap; 936 937 switch (encap->encap_type) { 938 default: 939 goto error; 940 case UDP_ENCAP_ESPINUDP: 941 x->props.header_len += sizeof(struct udphdr); 942 break; 943 case UDP_ENCAP_ESPINUDP_NON_IKE: 944 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 945 break; 946 } 947 } 948 949 align = ALIGN(crypto_aead_blocksize(aead), 4); 950 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 951 952 error: 953 return err; 954 } 955 956 static int esp4_rcv_cb(struct sk_buff *skb, int err) 957 { 958 return 0; 959 } 960 961 static const struct xfrm_type esp_type = 962 { 963 .description = "ESP4", 964 .owner = THIS_MODULE, 965 .proto = IPPROTO_ESP, 966 .flags = XFRM_TYPE_REPLAY_PROT, 967 .init_state = esp_init_state, 968 .destructor = esp_destroy, 969 .get_mtu = esp4_get_mtu, 970 .input = esp_input, 971 .output = esp_output, 972 }; 973 974 static struct xfrm4_protocol esp4_protocol = { 975 .handler = xfrm4_rcv, 976 .input_handler = xfrm_input, 977 .cb_handler = esp4_rcv_cb, 978 .err_handler = esp4_err, 979 .priority = 0, 980 }; 981 982 static int __init esp4_init(void) 983 { 984 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 985 pr_info("%s: can't add xfrm type\n", __func__); 986 return -EAGAIN; 987 } 988 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 989 pr_info("%s: can't add protocol\n", __func__); 990 xfrm_unregister_type(&esp_type, AF_INET); 991 return -EAGAIN; 992 } 993 return 0; 994 } 995 996 static void __exit esp4_fini(void) 997 { 998 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 999 pr_info("%s: can't remove protocol\n", __func__); 1000 if (xfrm_unregister_type(&esp_type, AF_INET) < 0) 1001 pr_info("%s: can't remove xfrm type\n", __func__); 1002 } 1003 1004 module_init(esp4_init); 1005 module_exit(esp4_fini); 1006 MODULE_LICENSE("GPL"); 1007 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1008