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 int esph_offset; 252 struct page *page; 253 struct sk_buff *trailer; 254 int tailen = esp->tailen; 255 256 /* this is non-NULL only with UDP Encapsulation */ 257 if (x->encap) 258 esp_output_udp_encap(x, skb, esp); 259 260 if (!skb_cloned(skb)) { 261 if (tailen <= skb_availroom(skb)) { 262 nfrags = 1; 263 trailer = skb; 264 tail = skb_tail_pointer(trailer); 265 266 goto skip_cow; 267 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 268 && !skb_has_frag_list(skb)) { 269 int allocsize; 270 struct sock *sk = skb->sk; 271 struct page_frag *pfrag = &x->xfrag; 272 273 esp->inplace = false; 274 275 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 276 277 spin_lock_bh(&x->lock); 278 279 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 280 spin_unlock_bh(&x->lock); 281 goto cow; 282 } 283 284 page = pfrag->page; 285 get_page(page); 286 287 vaddr = kmap_atomic(page); 288 289 tail = vaddr + pfrag->offset; 290 291 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 292 293 kunmap_atomic(vaddr); 294 295 spin_unlock_bh(&x->lock); 296 297 nfrags = skb_shinfo(skb)->nr_frags; 298 299 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 300 tailen); 301 skb_shinfo(skb)->nr_frags = ++nfrags; 302 303 pfrag->offset = pfrag->offset + allocsize; 304 nfrags++; 305 306 skb->len += tailen; 307 skb->data_len += tailen; 308 skb->truesize += tailen; 309 if (sk) 310 atomic_add(tailen, &sk->sk_wmem_alloc); 311 312 goto out; 313 } 314 } 315 316 cow: 317 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 318 319 nfrags = skb_cow_data(skb, tailen, &trailer); 320 if (nfrags < 0) 321 goto out; 322 tail = skb_tail_pointer(trailer); 323 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 324 325 skip_cow: 326 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 327 pskb_put(skb, trailer, tailen); 328 329 out: 330 return nfrags; 331 } 332 EXPORT_SYMBOL_GPL(esp_output_head); 333 334 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 335 { 336 u8 *iv; 337 int alen; 338 void *tmp; 339 int ivlen; 340 int assoclen; 341 int extralen; 342 struct page *page; 343 struct ip_esp_hdr *esph; 344 struct crypto_aead *aead; 345 struct aead_request *req; 346 struct scatterlist *sg, *dsg; 347 struct esp_output_extra *extra; 348 int err = -ENOMEM; 349 350 assoclen = sizeof(struct ip_esp_hdr); 351 extralen = 0; 352 353 if (x->props.flags & XFRM_STATE_ESN) { 354 extralen += sizeof(*extra); 355 assoclen += sizeof(__be32); 356 } 357 358 aead = x->data; 359 alen = crypto_aead_authsize(aead); 360 ivlen = crypto_aead_ivsize(aead); 361 362 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 363 if (!tmp) 364 goto error; 365 366 extra = esp_tmp_extra(tmp); 367 iv = esp_tmp_iv(aead, tmp, extralen); 368 req = esp_tmp_req(aead, iv); 369 sg = esp_req_sg(aead, req); 370 371 if (esp->inplace) 372 dsg = sg; 373 else 374 dsg = &sg[esp->nfrags]; 375 376 esph = esp_output_set_extra(skb, x, esp->esph, extra); 377 esp->esph = esph; 378 379 sg_init_table(sg, esp->nfrags); 380 skb_to_sgvec(skb, sg, 381 (unsigned char *)esph - skb->data, 382 assoclen + ivlen + esp->clen + alen); 383 384 if (!esp->inplace) { 385 int allocsize; 386 struct page_frag *pfrag = &x->xfrag; 387 388 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 389 390 spin_lock_bh(&x->lock); 391 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 392 spin_unlock_bh(&x->lock); 393 goto error; 394 } 395 396 skb_shinfo(skb)->nr_frags = 1; 397 398 page = pfrag->page; 399 get_page(page); 400 /* replace page frags in skb with new page */ 401 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 402 pfrag->offset = pfrag->offset + allocsize; 403 spin_unlock_bh(&x->lock); 404 405 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 406 skb_to_sgvec(skb, dsg, 407 (unsigned char *)esph - skb->data, 408 assoclen + ivlen + esp->clen + alen); 409 } 410 411 if ((x->props.flags & XFRM_STATE_ESN)) 412 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 413 else 414 aead_request_set_callback(req, 0, esp_output_done, skb); 415 416 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 417 aead_request_set_ad(req, assoclen); 418 419 memset(iv, 0, ivlen); 420 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 421 min(ivlen, 8)); 422 423 ESP_SKB_CB(skb)->tmp = tmp; 424 err = crypto_aead_encrypt(req); 425 426 switch (err) { 427 case -EINPROGRESS: 428 goto error; 429 430 case -EBUSY: 431 err = NET_XMIT_DROP; 432 break; 433 434 case 0: 435 if ((x->props.flags & XFRM_STATE_ESN)) 436 esp_output_restore_header(skb); 437 } 438 439 if (sg != dsg) 440 esp_ssg_unref(x, tmp); 441 kfree(tmp); 442 443 error: 444 return err; 445 } 446 EXPORT_SYMBOL_GPL(esp_output_tail); 447 448 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 449 { 450 int alen; 451 int blksize; 452 struct ip_esp_hdr *esph; 453 struct crypto_aead *aead; 454 struct esp_info esp; 455 456 esp.inplace = true; 457 458 esp.proto = *skb_mac_header(skb); 459 *skb_mac_header(skb) = IPPROTO_ESP; 460 461 /* skb is pure payload to encrypt */ 462 463 aead = x->data; 464 alen = crypto_aead_authsize(aead); 465 466 esp.tfclen = 0; 467 if (x->tfcpad) { 468 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 469 u32 padto; 470 471 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached)); 472 if (skb->len < padto) 473 esp.tfclen = padto - skb->len; 474 } 475 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 476 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 477 esp.plen = esp.clen - skb->len - esp.tfclen; 478 esp.tailen = esp.tfclen + esp.plen + alen; 479 480 esp.esph = ip_esp_hdr(skb); 481 482 esp.nfrags = esp_output_head(x, skb, &esp); 483 if (esp.nfrags < 0) 484 return esp.nfrags; 485 486 esph = esp.esph; 487 esph->spi = x->id.spi; 488 489 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 490 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 491 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 492 493 skb_push(skb, -skb_network_offset(skb)); 494 495 return esp_output_tail(x, skb, &esp); 496 } 497 498 int esp_input_done2(struct sk_buff *skb, int err) 499 { 500 const struct iphdr *iph; 501 struct xfrm_state *x = xfrm_input_state(skb); 502 struct xfrm_offload *xo = xfrm_offload(skb); 503 struct crypto_aead *aead = x->data; 504 int alen = crypto_aead_authsize(aead); 505 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 506 int elen = skb->len - hlen; 507 int ihl; 508 u8 nexthdr[2]; 509 int padlen; 510 511 if (!xo || (xo && !(xo->flags & CRYPTO_DONE))) 512 kfree(ESP_SKB_CB(skb)->tmp); 513 514 if (unlikely(err)) 515 goto out; 516 517 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) 518 BUG(); 519 520 err = -EINVAL; 521 padlen = nexthdr[0]; 522 if (padlen + 2 + alen >= elen) 523 goto out; 524 525 /* ... check padding bits here. Silly. :-) */ 526 527 iph = ip_hdr(skb); 528 ihl = iph->ihl * 4; 529 530 if (x->encap) { 531 struct xfrm_encap_tmpl *encap = x->encap; 532 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 533 534 /* 535 * 1) if the NAT-T peer's IP or port changed then 536 * advertize the change to the keying daemon. 537 * This is an inbound SA, so just compare 538 * SRC ports. 539 */ 540 if (iph->saddr != x->props.saddr.a4 || 541 uh->source != encap->encap_sport) { 542 xfrm_address_t ipaddr; 543 544 ipaddr.a4 = iph->saddr; 545 km_new_mapping(x, &ipaddr, uh->source); 546 547 /* XXX: perhaps add an extra 548 * policy check here, to see 549 * if we should allow or 550 * reject a packet from a 551 * different source 552 * address/port. 553 */ 554 } 555 556 /* 557 * 2) ignore UDP/TCP checksums in case 558 * of NAT-T in Transport Mode, or 559 * perform other post-processing fixes 560 * as per draft-ietf-ipsec-udp-encaps-06, 561 * section 3.1.2 562 */ 563 if (x->props.mode == XFRM_MODE_TRANSPORT) 564 skb->ip_summed = CHECKSUM_UNNECESSARY; 565 } 566 567 pskb_trim(skb, skb->len - alen - padlen - 2); 568 __skb_pull(skb, hlen); 569 if (x->props.mode == XFRM_MODE_TUNNEL) 570 skb_reset_transport_header(skb); 571 else 572 skb_set_transport_header(skb, -ihl); 573 574 err = nexthdr[1]; 575 576 /* RFC4303: Drop dummy packets without any error */ 577 if (err == IPPROTO_NONE) 578 err = -EINVAL; 579 580 out: 581 return err; 582 } 583 EXPORT_SYMBOL_GPL(esp_input_done2); 584 585 static void esp_input_done(struct crypto_async_request *base, int err) 586 { 587 struct sk_buff *skb = base->data; 588 589 xfrm_input_resume(skb, esp_input_done2(skb, err)); 590 } 591 592 static void esp_input_restore_header(struct sk_buff *skb) 593 { 594 esp_restore_header(skb, 0); 595 __skb_pull(skb, 4); 596 } 597 598 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 599 { 600 struct xfrm_state *x = xfrm_input_state(skb); 601 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)skb->data; 602 603 /* For ESN we move the header forward by 4 bytes to 604 * accomodate the high bits. We will move it back after 605 * decryption. 606 */ 607 if ((x->props.flags & XFRM_STATE_ESN)) { 608 esph = (void *)skb_push(skb, 4); 609 *seqhi = esph->spi; 610 esph->spi = esph->seq_no; 611 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 612 } 613 } 614 615 static void esp_input_done_esn(struct crypto_async_request *base, int err) 616 { 617 struct sk_buff *skb = base->data; 618 619 esp_input_restore_header(skb); 620 esp_input_done(base, err); 621 } 622 623 /* 624 * Note: detecting truncated vs. non-truncated authentication data is very 625 * expensive, so we only support truncated data, which is the recommended 626 * and common case. 627 */ 628 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 629 { 630 struct ip_esp_hdr *esph; 631 struct crypto_aead *aead = x->data; 632 struct aead_request *req; 633 struct sk_buff *trailer; 634 int ivlen = crypto_aead_ivsize(aead); 635 int elen = skb->len - sizeof(*esph) - ivlen; 636 int nfrags; 637 int assoclen; 638 int seqhilen; 639 __be32 *seqhi; 640 void *tmp; 641 u8 *iv; 642 struct scatterlist *sg; 643 int err = -EINVAL; 644 645 if (!pskb_may_pull(skb, sizeof(*esph) + ivlen)) 646 goto out; 647 648 if (elen <= 0) 649 goto out; 650 651 assoclen = sizeof(*esph); 652 seqhilen = 0; 653 654 if (x->props.flags & XFRM_STATE_ESN) { 655 seqhilen += sizeof(__be32); 656 assoclen += seqhilen; 657 } 658 659 if (!skb_cloned(skb)) { 660 if (!skb_is_nonlinear(skb)) { 661 nfrags = 1; 662 663 goto skip_cow; 664 } else if (!skb_has_frag_list(skb)) { 665 nfrags = skb_shinfo(skb)->nr_frags; 666 nfrags++; 667 668 goto skip_cow; 669 } 670 } 671 672 err = skb_cow_data(skb, 0, &trailer); 673 if (err < 0) 674 goto out; 675 676 nfrags = err; 677 678 skip_cow: 679 err = -ENOMEM; 680 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 681 if (!tmp) 682 goto out; 683 684 ESP_SKB_CB(skb)->tmp = tmp; 685 seqhi = esp_tmp_extra(tmp); 686 iv = esp_tmp_iv(aead, tmp, seqhilen); 687 req = esp_tmp_req(aead, iv); 688 sg = esp_req_sg(aead, req); 689 690 esp_input_set_header(skb, seqhi); 691 692 sg_init_table(sg, nfrags); 693 skb_to_sgvec(skb, sg, 0, skb->len); 694 695 skb->ip_summed = CHECKSUM_NONE; 696 697 if ((x->props.flags & XFRM_STATE_ESN)) 698 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 699 else 700 aead_request_set_callback(req, 0, esp_input_done, skb); 701 702 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 703 aead_request_set_ad(req, assoclen); 704 705 err = crypto_aead_decrypt(req); 706 if (err == -EINPROGRESS) 707 goto out; 708 709 if ((x->props.flags & XFRM_STATE_ESN)) 710 esp_input_restore_header(skb); 711 712 err = esp_input_done2(skb, err); 713 714 out: 715 return err; 716 } 717 718 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu) 719 { 720 struct crypto_aead *aead = x->data; 721 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 722 unsigned int net_adj; 723 724 switch (x->props.mode) { 725 case XFRM_MODE_TRANSPORT: 726 case XFRM_MODE_BEET: 727 net_adj = sizeof(struct iphdr); 728 break; 729 case XFRM_MODE_TUNNEL: 730 net_adj = 0; 731 break; 732 default: 733 BUG(); 734 } 735 736 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) - 737 net_adj) & ~(blksize - 1)) + net_adj - 2; 738 } 739 740 static int esp4_err(struct sk_buff *skb, u32 info) 741 { 742 struct net *net = dev_net(skb->dev); 743 const struct iphdr *iph = (const struct iphdr *)skb->data; 744 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 745 struct xfrm_state *x; 746 747 switch (icmp_hdr(skb)->type) { 748 case ICMP_DEST_UNREACH: 749 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 750 return 0; 751 case ICMP_REDIRECT: 752 break; 753 default: 754 return 0; 755 } 756 757 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 758 esph->spi, IPPROTO_ESP, AF_INET); 759 if (!x) 760 return 0; 761 762 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 763 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0); 764 else 765 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0); 766 xfrm_state_put(x); 767 768 return 0; 769 } 770 771 static void esp_destroy(struct xfrm_state *x) 772 { 773 struct crypto_aead *aead = x->data; 774 775 if (!aead) 776 return; 777 778 crypto_free_aead(aead); 779 } 780 781 static int esp_init_aead(struct xfrm_state *x) 782 { 783 char aead_name[CRYPTO_MAX_ALG_NAME]; 784 struct crypto_aead *aead; 785 int err; 786 u32 mask = 0; 787 788 err = -ENAMETOOLONG; 789 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 790 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 791 goto error; 792 793 if (x->xso.offload_handle) 794 mask |= CRYPTO_ALG_ASYNC; 795 796 aead = crypto_alloc_aead(aead_name, 0, mask); 797 err = PTR_ERR(aead); 798 if (IS_ERR(aead)) 799 goto error; 800 801 x->data = aead; 802 803 err = crypto_aead_setkey(aead, x->aead->alg_key, 804 (x->aead->alg_key_len + 7) / 8); 805 if (err) 806 goto error; 807 808 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 809 if (err) 810 goto error; 811 812 error: 813 return err; 814 } 815 816 static int esp_init_authenc(struct xfrm_state *x) 817 { 818 struct crypto_aead *aead; 819 struct crypto_authenc_key_param *param; 820 struct rtattr *rta; 821 char *key; 822 char *p; 823 char authenc_name[CRYPTO_MAX_ALG_NAME]; 824 unsigned int keylen; 825 int err; 826 u32 mask = 0; 827 828 err = -EINVAL; 829 if (!x->ealg) 830 goto error; 831 832 err = -ENAMETOOLONG; 833 834 if ((x->props.flags & XFRM_STATE_ESN)) { 835 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 836 "%s%sauthencesn(%s,%s)%s", 837 x->geniv ?: "", x->geniv ? "(" : "", 838 x->aalg ? x->aalg->alg_name : "digest_null", 839 x->ealg->alg_name, 840 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 841 goto error; 842 } else { 843 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 844 "%s%sauthenc(%s,%s)%s", 845 x->geniv ?: "", x->geniv ? "(" : "", 846 x->aalg ? x->aalg->alg_name : "digest_null", 847 x->ealg->alg_name, 848 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 849 goto error; 850 } 851 852 if (x->xso.offload_handle) 853 mask |= CRYPTO_ALG_ASYNC; 854 855 aead = crypto_alloc_aead(authenc_name, 0, mask); 856 err = PTR_ERR(aead); 857 if (IS_ERR(aead)) 858 goto error; 859 860 x->data = aead; 861 862 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 863 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 864 err = -ENOMEM; 865 key = kmalloc(keylen, GFP_KERNEL); 866 if (!key) 867 goto error; 868 869 p = key; 870 rta = (void *)p; 871 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 872 rta->rta_len = RTA_LENGTH(sizeof(*param)); 873 param = RTA_DATA(rta); 874 p += RTA_SPACE(sizeof(*param)); 875 876 if (x->aalg) { 877 struct xfrm_algo_desc *aalg_desc; 878 879 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 880 p += (x->aalg->alg_key_len + 7) / 8; 881 882 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 883 BUG_ON(!aalg_desc); 884 885 err = -EINVAL; 886 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 887 crypto_aead_authsize(aead)) { 888 pr_info("ESP: %s digestsize %u != %hu\n", 889 x->aalg->alg_name, 890 crypto_aead_authsize(aead), 891 aalg_desc->uinfo.auth.icv_fullbits / 8); 892 goto free_key; 893 } 894 895 err = crypto_aead_setauthsize( 896 aead, x->aalg->alg_trunc_len / 8); 897 if (err) 898 goto free_key; 899 } 900 901 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 902 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 903 904 err = crypto_aead_setkey(aead, key, keylen); 905 906 free_key: 907 kfree(key); 908 909 error: 910 return err; 911 } 912 913 static int esp_init_state(struct xfrm_state *x) 914 { 915 struct crypto_aead *aead; 916 u32 align; 917 int err; 918 919 x->data = NULL; 920 921 if (x->aead) 922 err = esp_init_aead(x); 923 else 924 err = esp_init_authenc(x); 925 926 if (err) 927 goto error; 928 929 aead = x->data; 930 931 x->props.header_len = sizeof(struct ip_esp_hdr) + 932 crypto_aead_ivsize(aead); 933 if (x->props.mode == XFRM_MODE_TUNNEL) 934 x->props.header_len += sizeof(struct iphdr); 935 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 936 x->props.header_len += IPV4_BEET_PHMAXLEN; 937 if (x->encap) { 938 struct xfrm_encap_tmpl *encap = x->encap; 939 940 switch (encap->encap_type) { 941 default: 942 goto error; 943 case UDP_ENCAP_ESPINUDP: 944 x->props.header_len += sizeof(struct udphdr); 945 break; 946 case UDP_ENCAP_ESPINUDP_NON_IKE: 947 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 948 break; 949 } 950 } 951 952 align = ALIGN(crypto_aead_blocksize(aead), 4); 953 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 954 955 error: 956 return err; 957 } 958 959 static int esp4_rcv_cb(struct sk_buff *skb, int err) 960 { 961 return 0; 962 } 963 964 static const struct xfrm_type esp_type = 965 { 966 .description = "ESP4", 967 .owner = THIS_MODULE, 968 .proto = IPPROTO_ESP, 969 .flags = XFRM_TYPE_REPLAY_PROT, 970 .init_state = esp_init_state, 971 .destructor = esp_destroy, 972 .get_mtu = esp4_get_mtu, 973 .input = esp_input, 974 .output = esp_output, 975 }; 976 977 static struct xfrm4_protocol esp4_protocol = { 978 .handler = xfrm4_rcv, 979 .input_handler = xfrm_input, 980 .cb_handler = esp4_rcv_cb, 981 .err_handler = esp4_err, 982 .priority = 0, 983 }; 984 985 static int __init esp4_init(void) 986 { 987 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 988 pr_info("%s: can't add xfrm type\n", __func__); 989 return -EAGAIN; 990 } 991 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 992 pr_info("%s: can't add protocol\n", __func__); 993 xfrm_unregister_type(&esp_type, AF_INET); 994 return -EAGAIN; 995 } 996 return 0; 997 } 998 999 static void __exit esp4_fini(void) 1000 { 1001 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1002 pr_info("%s: can't remove protocol\n", __func__); 1003 if (xfrm_unregister_type(&esp_type, AF_INET) < 0) 1004 pr_info("%s: can't remove xfrm type\n", __func__); 1005 } 1006 1007 module_init(esp4_init); 1008 module_exit(esp4_fini); 1009 MODULE_LICENSE("GPL"); 1010 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1011