net/xfrm/xfrm_algo.c

   1 /*
   2  * xfrm algorithm interface
   3  *
   4  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/pfkeyv2.h>
  16 #include <net/xfrm.h>
  17 #if defined(CONFIG_INET_AH) || defined(CONFIG_INET_AH_MODULE) || defined(CONFIG_INET6_AH) || defined(CONFIG_INET6_AH_MODULE)
  18 #include <net/ah.h>
  19 #endif
  20 #if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)
  21 #include <net/esp.h>
  22 #endif
  23 #include <asm/scatterlist.h>
  24
  25 /*
  26  * Algorithms supported by IPsec.  These entries contain properties which
  27  * are used in key negotiation and xfrm processing, and are used to verify
  28  * that instantiated crypto transforms have correct parameters for IPsec
  29  * purposes.
  30  */
  31 static struct xfrm_algo_desc aalg_list[] = {
  32 {
  33         .name = "digest_null",
  34
  35         .uinfo = {
  36                 .auth = {
  37                         .icv_truncbits = 0,
  38                         .icv_fullbits = 0,
  39                 }
  40         },
  41
  42         .desc = {
  43                 .sadb_alg_id = SADB_X_AALG_NULL,
  44                 .sadb_alg_ivlen = 0,
  45                 .sadb_alg_minbits = 0,
  46                 .sadb_alg_maxbits = 0
  47         }
  48 },
  49 {
  50         .name = "md5",
  51
  52         .uinfo = {
  53                 .auth = {
  54                         .icv_truncbits = 96,
  55                         .icv_fullbits = 128,
  56                 }
  57         },
  58
  59         .desc = {
  60                 .sadb_alg_id = SADB_AALG_MD5HMAC,
  61                 .sadb_alg_ivlen = 0,
  62                 .sadb_alg_minbits = 128,
  63                 .sadb_alg_maxbits = 128
  64         }
  65 },
  66 {
  67         .name = "sha1",
  68
  69         .uinfo = {
  70                 .auth = {
  71                         .icv_truncbits = 96,
  72                         .icv_fullbits = 160,
  73                 }
  74         },
  75
  76         .desc = {
  77                 .sadb_alg_id = SADB_AALG_SHA1HMAC,
  78                 .sadb_alg_ivlen = 0,
  79                 .sadb_alg_minbits = 160,
  80                 .sadb_alg_maxbits = 160
  81         }
  82 },
  83 {
  84         .name = "sha256",
  85
  86         .uinfo = {
  87                 .auth = {
  88                         .icv_truncbits = 96,
  89                         .icv_fullbits = 256,
  90                 }
  91         },
  92
  93         .desc = {
  94                 .sadb_alg_id = SADB_X_AALG_SHA2_256HMAC,
  95                 .sadb_alg_ivlen = 0,
  96                 .sadb_alg_minbits = 256,
  97                 .sadb_alg_maxbits = 256
  98         }
  99 },
 100 {
 101         .name = "ripemd160",
 102
 103         .uinfo = {
 104                 .auth = {
 105                         .icv_truncbits = 96,
 106                         .icv_fullbits = 160,
 107                 }
 108         },
 109
 110         .desc = {
 111                 .sadb_alg_id = SADB_X_AALG_RIPEMD160HMAC,
 112                 .sadb_alg_ivlen = 0,
 113                 .sadb_alg_minbits = 160,
 114                 .sadb_alg_maxbits = 160
 115         }
 116 },
 117 };
 118
 119 static struct xfrm_algo_desc ealg_list[] = {
 120 {
 121         .name = "cipher_null",
 122
 123         .uinfo = {
 124                 .encr = {
 125                         .blockbits = 8,
 126                         .defkeybits = 0,
 127                 }
 128         },
 129
 130         .desc = {
 131                 .sadb_alg_id =  SADB_EALG_NULL,
 132                 .sadb_alg_ivlen = 0,
 133                 .sadb_alg_minbits = 0,
 134                 .sadb_alg_maxbits = 0
 135         }
 136 },
 137 {
 138         .name = "des",
 139
 140         .uinfo = {
 141                 .encr = {
 142                         .blockbits = 64,
 143                         .defkeybits = 64,
 144                 }
 145         },
 146
 147         .desc = {
 148                 .sadb_alg_id = SADB_EALG_DESCBC,
 149                 .sadb_alg_ivlen = 8,
 150                 .sadb_alg_minbits = 64,
 151                 .sadb_alg_maxbits = 64
 152         }
 153 },
 154 {
 155         .name = "des3_ede",
 156
 157         .uinfo = {
 158                 .encr = {
 159                         .blockbits = 64,
 160                         .defkeybits = 192,
 161                 }
 162         },
 163
 164         .desc = {
 165                 .sadb_alg_id = SADB_EALG_3DESCBC,
 166                 .sadb_alg_ivlen = 8,
 167                 .sadb_alg_minbits = 192,
 168                 .sadb_alg_maxbits = 192
 169         }
 170 },
 171 {
 172         .name = "cast128",
 173
 174         .uinfo = {
 175                 .encr = {
 176                         .blockbits = 64,
 177                         .defkeybits = 128,
 178                 }
 179         },
 180
 181         .desc = {
 182                 .sadb_alg_id = SADB_X_EALG_CASTCBC,
 183                 .sadb_alg_ivlen = 8,
 184                 .sadb_alg_minbits = 40,
 185                 .sadb_alg_maxbits = 128
 186         }
 187 },
 188 {
 189         .name = "blowfish",
 190
 191         .uinfo = {
 192                 .encr = {
 193                         .blockbits = 64,
 194                         .defkeybits = 128,
 195                 }
 196         },
 197
 198         .desc = {
 199                 .sadb_alg_id = SADB_X_EALG_BLOWFISHCBC,
 200                 .sadb_alg_ivlen = 8,
 201                 .sadb_alg_minbits = 40,
 202                 .sadb_alg_maxbits = 448
 203         }
 204 },
 205 {
 206         .name = "aes",
 207
 208         .uinfo = {
 209                 .encr = {
 210                         .blockbits = 128,
 211                         .defkeybits = 128,
 212                 }
 213         },
 214
 215         .desc = {
 216                 .sadb_alg_id = SADB_X_EALG_AESCBC,
 217                 .sadb_alg_ivlen = 8,
 218                 .sadb_alg_minbits = 128,
 219                 .sadb_alg_maxbits = 256
 220         }
 221 },
 222 {
 223         .name = "serpent",
 224
 225         .uinfo = {
 226                 .encr = {
 227                         .blockbits = 128,
 228                         .defkeybits = 128,
 229                 }
 230         },
 231
 232         .desc = {
 233                 .sadb_alg_id = SADB_X_EALG_SERPENTCBC,
 234                 .sadb_alg_ivlen = 8,
 235                 .sadb_alg_minbits = 128,
 236                 .sadb_alg_maxbits = 256,
 237         }
 238 },
 239 {
 240         .name = "twofish",
 241
 242         .uinfo = {
 243                 .encr = {
 244                         .blockbits = 128,
 245                         .defkeybits = 128,
 246                 }
 247         },
 248
 249         .desc = {
 250                 .sadb_alg_id = SADB_X_EALG_TWOFISHCBC,
 251                 .sadb_alg_ivlen = 8,
 252                 .sadb_alg_minbits = 128,
 253                 .sadb_alg_maxbits = 256
 254         }
 255 },
 256 };
 257
 258 static struct xfrm_algo_desc calg_list[] = {
 259 {
 260         .name = "deflate",
 261         .uinfo = {
 262                 .comp = {
 263                         .threshold = 90,
 264                 }
 265         },
 266         .desc = { .sadb_alg_id = SADB_X_CALG_DEFLATE }
 267 },
 268 {
 269         .name = "lzs",
 270         .uinfo = {
 271                 .comp = {
 272                         .threshold = 90,
 273                 }
 274         },
 275         .desc = { .sadb_alg_id = SADB_X_CALG_LZS }
 276 },
 277 {
 278         .name = "lzjh",
 279         .uinfo = {
 280                 .comp = {
 281                         .threshold = 50,
 282                 }
 283         },
 284         .desc = { .sadb_alg_id = SADB_X_CALG_LZJH }
 285 },
 286 };
 287
 288 static inline int aalg_entries(void)
 289 {
 290         return ARRAY_SIZE(aalg_list);
 291 }
 292
 293 static inline int ealg_entries(void)
 294 {
 295         return ARRAY_SIZE(ealg_list);
 296 }
 297
 298 static inline int calg_entries(void)
 299 {
 300         return ARRAY_SIZE(calg_list);
 301 }
 302
 303 /* Todo: generic iterators */
 304 struct xfrm_algo_desc *xfrm_aalg_get_byid(int alg_id)
 305 {
 306         int i;
 307
 308         for (i = 0; i < aalg_entries(); i++) {
 309                 if (aalg_list[i].desc.sadb_alg_id == alg_id) {
 310                         if (aalg_list[i].available)
 311                                 return &aalg_list[i];
 312                         else
 313                                 break;
 314                 }
 315         }
 316         return NULL;
 317 }
 318
 319 struct xfrm_algo_desc *xfrm_ealg_get_byid(int alg_id)
 320 {
 321         int i;
 322
 323         for (i = 0; i < ealg_entries(); i++) {
 324                 if (ealg_list[i].desc.sadb_alg_id == alg_id) {
 325                         if (ealg_list[i].available)
 326                                 return &ealg_list[i];
 327                         else
 328                                 break;
 329                 }
 330         }
 331         return NULL;
 332 }
 333
 334 struct xfrm_algo_desc *xfrm_calg_get_byid(int alg_id)
 335 {
 336         int i;
 337
 338         for (i = 0; i < calg_entries(); i++) {
 339                 if (calg_list[i].desc.sadb_alg_id == alg_id) {
 340                         if (calg_list[i].available)
 341                                 return &calg_list[i];
 342                         else
 343                                 break;
 344                 }
 345         }
 346         return NULL;
 347 }
 348
 349 struct xfrm_algo_desc *xfrm_aalg_get_byname(char *name)
 350 {
 351         int i;
 352
 353         if (!name)
 354                 return NULL;
 355
 356         for (i=0; i < aalg_entries(); i++) {
 357                 if (strcmp(name, aalg_list[i].name) == 0) {
 358                         if (aalg_list[i].available)
 359                                 return &aalg_list[i];
 360                         else
 361                                 break;
 362                 }
 363         }
 364         return NULL;
 365 }
 366
 367 struct xfrm_algo_desc *xfrm_ealg_get_byname(char *name)
 368 {
 369         int i;
 370
 371         if (!name)
 372                 return NULL;
 373
 374         for (i=0; i < ealg_entries(); i++) {
 375                 if (strcmp(name, ealg_list[i].name) == 0) {
 376                         if (ealg_list[i].available)
 377                                 return &ealg_list[i];
 378                         else
 379                                 break;
 380                 }
 381         }
 382         return NULL;
 383 }
 384
 385 struct xfrm_algo_desc *xfrm_calg_get_byname(char *name)
 386 {
 387         int i;
 388
 389         if (!name)
 390                 return NULL;
 391
 392         for (i=0; i < calg_entries(); i++) {
 393                 if (strcmp(name, calg_list[i].name) == 0) {
 394                         if (calg_list[i].available)
 395                                 return &calg_list[i];
 396                         else
 397                                 break;
 398                 }
 399         }
 400         return NULL;
 401 }
 402
 403 struct xfrm_algo_desc *xfrm_aalg_get_byidx(unsigned int idx)
 404 {
 405         if (idx >= aalg_entries())
 406                 return NULL;
 407
 408         return &aalg_list[idx];
 409 }
 410
 411 struct xfrm_algo_desc *xfrm_ealg_get_byidx(unsigned int idx)
 412 {
 413         if (idx >= ealg_entries())
 414                 return NULL;
 415
 416         return &ealg_list[idx];
 417 }
 418
 419 struct xfrm_algo_desc *xfrm_calg_get_byidx(unsigned int idx)
 420 {
 421         if (idx >= calg_entries())
 422                 return NULL;
 423
 424         return &calg_list[idx];
 425 }
 426
 427 /*
 428  * Probe for the availability of crypto algorithms, and set the available
 429  * flag for any algorithms found on the system.  This is typically called by
 430  * pfkey during userspace SA add, update or register.
 431  */
 432 void xfrm_probe_algs(void)
 433 {
 434 #ifdef CONFIG_CRYPTO
 435         int i, status;
 436
 437         BUG_ON(in_softirq());
 438
 439         for (i = 0; i < aalg_entries(); i++) {
 440                 status = crypto_alg_available(aalg_list[i].name, 0);
 441                 if (aalg_list[i].available != status)
 442                         aalg_list[i].available = status;
 443         }
 444
 445         for (i = 0; i < ealg_entries(); i++) {
 446                 status = crypto_alg_available(ealg_list[i].name, 0);
 447                 if (ealg_list[i].available != status)
 448                         ealg_list[i].available = status;
 449         }
 450
 451         for (i = 0; i < calg_entries(); i++) {
 452                 status = crypto_alg_available(calg_list[i].name, 0);
 453                 if (calg_list[i].available != status)
 454                         calg_list[i].available = status;
 455         }
 456 #endif
 457 }
 458
 459 int xfrm_count_auth_supported(void)
 460 {
 461         int i, n;
 462
 463         for (i = 0, n = 0; i < aalg_entries(); i++)
 464                 if (aalg_list[i].available)
 465                         n++;
 466         return n;
 467 }
 468
 469 int xfrm_count_enc_supported(void)
 470 {
 471         int i, n;
 472
 473         for (i = 0, n = 0; i < ealg_entries(); i++)
 474                 if (ealg_list[i].available)
 475                         n++;
 476         return n;
 477 }
 478
 479 /* Move to common area: it is shared with AH. */
 480
 481 void skb_icv_walk(const struct sk_buff *skb, struct crypto_tfm *tfm,
 482                   int offset, int len, icv_update_fn_t icv_update)
 483 {
 484         int start = skb_headlen(skb);
 485         int i, copy = start - offset;
 486         struct scatterlist sg;
 487
 488         /* Checksum header. */
 489         if (copy > 0) {
 490                 if (copy > len)
 491                         copy = len;
 492
 493                 sg.page = virt_to_page(skb->data + offset);
 494                 sg.offset = (unsigned long)(skb->data + offset) % PAGE_SIZE;
 495                 sg.length = copy;
 496
 497                 icv_update(tfm, &sg, 1);
 498
 499                 if ((len -= copy) == 0)
 500                         return;
 501                 offset += copy;
 502         }
 503
 504         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 505                 int end;
 506
 507                 BUG_TRAP(start <= offset + len);
 508
 509                 end = start + skb_shinfo(skb)->frags[i].size;
 510                 if ((copy = end - offset) > 0) {
 511                         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 512
 513                         if (copy > len)
 514                                 copy = len;
 515
 516                         sg.page = frag->page;
 517                         sg.offset = frag->page_offset + offset-start;
 518                         sg.length = copy;
 519
 520                         icv_update(tfm, &sg, 1);
 521
 522                         if (!(len -= copy))
 523                                 return;
 524                         offset += copy;
 525                 }
 526                 start = end;
 527         }
 528
 529         if (skb_shinfo(skb)->frag_list) {
 530                 struct sk_buff *list = skb_shinfo(skb)->frag_list;
 531
 532                 for (; list; list = list->next) {
 533                         int end;
 534
 535                         BUG_TRAP(start <= offset + len);
 536
 537                         end = start + list->len;
 538                         if ((copy = end - offset) > 0) {
 539                                 if (copy > len)
 540                                         copy = len;
 541                                 skb_icv_walk(list, tfm, offset-start, copy, icv_update);
 542                                 if ((len -= copy) == 0)
 543                                         return;
 544                                 offset += copy;
 545                         }
 546                         start = end;
 547                 }
 548         }
 549         if (len)
 550                 BUG();
 551 }
 552
 553 #if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)
 554
 555 /* Looking generic it is not used in another places. */
 556
 557 int
 558 skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
 559 {
 560         int start = skb_headlen(skb);
 561         int i, copy = start - offset;
 562         int elt = 0;
 563
 564         if (copy > 0) {
 565                 if (copy > len)
 566                         copy = len;
 567                 sg[elt].page = virt_to_page(skb->data + offset);
 568                 sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE;
 569                 sg[elt].length = copy;
 570                 elt++;
 571                 if ((len -= copy) == 0)
 572                         return elt;
 573                 offset += copy;
 574         }
 575
 576         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 577                 int end;
 578
 579                 BUG_TRAP(start <= offset + len);
 580
 581                 end = start + skb_shinfo(skb)->frags[i].size;
 582                 if ((copy = end - offset) > 0) {
 583                         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 584
 585                         if (copy > len)
 586                                 copy = len;
 587                         sg[elt].page = frag->page;
 588                         sg[elt].offset = frag->page_offset+offset-start;
 589                         sg[elt].length = copy;
 590                         elt++;
 591                         if (!(len -= copy))
 592                                 return elt;
 593                         offset += copy;
 594                 }
 595                 start = end;
 596         }
 597
 598         if (skb_shinfo(skb)->frag_list) {
 599                 struct sk_buff *list = skb_shinfo(skb)->frag_list;
 600
 601                 for (; list; list = list->next) {
 602                         int end;
 603
 604                         BUG_TRAP(start <= offset + len);
 605
 606                         end = start + list->len;
 607                         if ((copy = end - offset) > 0) {
 608                                 if (copy > len)
 609                                         copy = len;
 610                                 elt += skb_to_sgvec(list, sg+elt, offset - start, copy);
 611                                 if ((len -= copy) == 0)
 612                                         return elt;
 613                                 offset += copy;
 614                         }
 615                         start = end;
 616                 }
 617         }
 618         if (len)
 619                 BUG();
 620         return elt;
 621 }
 622 EXPORT_SYMBOL_GPL(skb_to_sgvec);
 623
 624 /* Check that skb data bits are writable. If they are not, copy data
 625  * to newly created private area. If "tailbits" is given, make sure that
 626  * tailbits bytes beyond current end of skb are writable.
 627  *
 628  * Returns amount of elements of scatterlist to load for subsequent
 629  * transformations and pointer to writable trailer skb.
 630  */
 631
 632 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
 633 {
 634         int copyflag;
 635         int elt;
 636         struct sk_buff *skb1, **skb_p;
 637
 638         /* If skb is cloned or its head is paged, reallocate
 639          * head pulling out all the pages (pages are considered not writable
 640          * at the moment even if they are anonymous).
 641          */
 642         if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
 643             __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
 644                 return -ENOMEM;
 645
 646         /* Easy case. Most of packets will go this way. */
 647         if (!skb_shinfo(skb)->frag_list) {
 648                 /* A little of trouble, not enough of space for trailer.
 649                  * This should not happen, when stack is tuned to generate
 650                  * good frames. OK, on miss we reallocate and reserve even more
 651                  * space, 128 bytes is fair. */
 652
 653                 if (skb_tailroom(skb) < tailbits &&
 654                     pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
 655                         return -ENOMEM;
 656
 657                 /* Voila! */
 658                 *trailer = skb;
 659                 return 1;
 660         }
 661
 662         /* Misery. We are in troubles, going to mincer fragments... */
 663
 664         elt = 1;
 665         skb_p = &skb_shinfo(skb)->frag_list;
 666         copyflag = 0;
 667
 668         while ((skb1 = *skb_p) != NULL) {
 669                 int ntail = 0;
 670
 671                 /* The fragment is partially pulled by someone,
 672                  * this can happen on input. Copy it and everything
 673                  * after it. */
 674
 675                 if (skb_shared(skb1))
 676                         copyflag = 1;
 677
 678                 /* If the skb is the last, worry about trailer. */
 679
 680                 if (skb1->next == NULL && tailbits) {
 681                         if (skb_shinfo(skb1)->nr_frags ||
 682                             skb_shinfo(skb1)->frag_list ||
 683                             skb_tailroom(skb1) < tailbits)
 684                                 ntail = tailbits + 128;
 685                 }
 686
 687                 if (copyflag ||
 688                     skb_cloned(skb1) ||
 689                     ntail ||
 690                     skb_shinfo(skb1)->nr_frags ||
 691                     skb_shinfo(skb1)->frag_list) {
 692                         struct sk_buff *skb2;
 693
 694                         /* Fuck, we are miserable poor guys... */
 695                         if (ntail == 0)
 696                                 skb2 = skb_copy(skb1, GFP_ATOMIC);
 697                         else
 698                                 skb2 = skb_copy_expand(skb1,
 699                                                        skb_headroom(skb1),
 700                                                        ntail,
 701                                                        GFP_ATOMIC);
 702                         if (unlikely(skb2 == NULL))
 703                                 return -ENOMEM;
 704
 705                         if (skb1->sk)
 706                                 skb_set_owner_w(skb, skb1->sk);
 707
 708                         /* Looking around. Are we still alive?
 709                          * OK, link new skb, drop old one */
 710
 711                         skb2->next = skb1->next;
 712                         *skb_p = skb2;
 713                         kfree_skb(skb1);
 714                         skb1 = skb2;
 715                 }
 716                 elt++;
 717                 *trailer = skb1;
 718                 skb_p = &skb1->next;
 719         }
 720
 721         return elt;
 722 }
 723 EXPORT_SYMBOL_GPL(skb_cow_data);
 724
 725 void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
 726 {
 727         if (tail != skb) {
 728                 skb->data_len += len;
 729                 skb->len += len;
 730         }
 731         return skb_put(tail, len);
 732 }
 733 EXPORT_SYMBOL_GPL(pskb_put);
 734 #endif