1 /* 2 * VMAC: Message Authentication Code using Universal Hashing 3 * 4 * Reference: https://tools.ietf.org/html/draft-krovetz-vmac-01 5 * 6 * Copyright (c) 2009, Intel Corporation. 7 * Copyright (c) 2018, Google Inc. 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms and conditions of the GNU General Public License, 11 * version 2, as published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope it will be useful, but WITHOUT 14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 16 * more details. 17 * 18 * You should have received a copy of the GNU General Public License along with 19 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple 20 * Place - Suite 330, Boston, MA 02111-1307 USA. 21 */ 22 23 /* 24 * Derived from: 25 * VMAC and VHASH Implementation by Ted Krovetz (tdk@acm.org) and Wei Dai. 26 * This implementation is herby placed in the public domain. 27 * The authors offers no warranty. Use at your own risk. 28 * Last modified: 17 APR 08, 1700 PDT 29 */ 30 31 #include <asm/unaligned.h> 32 #include <linux/init.h> 33 #include <linux/types.h> 34 #include <linux/crypto.h> 35 #include <linux/module.h> 36 #include <linux/scatterlist.h> 37 #include <asm/byteorder.h> 38 #include <crypto/scatterwalk.h> 39 #include <crypto/internal/hash.h> 40 41 /* 42 * User definable settings. 43 */ 44 #define VMAC_TAG_LEN 64 45 #define VMAC_KEY_SIZE 128/* Must be 128, 192 or 256 */ 46 #define VMAC_KEY_LEN (VMAC_KEY_SIZE/8) 47 #define VMAC_NHBYTES 128/* Must 2^i for any 3 < i < 13 Standard = 128*/ 48 #define VMAC_NONCEBYTES 16 49 50 /* per-transform (per-key) context */ 51 struct vmac_tfm_ctx { 52 struct crypto_cipher *cipher; 53 u64 nhkey[(VMAC_NHBYTES/8)+2*(VMAC_TAG_LEN/64-1)]; 54 u64 polykey[2*VMAC_TAG_LEN/64]; 55 u64 l3key[2*VMAC_TAG_LEN/64]; 56 }; 57 58 /* per-request context */ 59 struct vmac_desc_ctx { 60 union { 61 u8 partial[VMAC_NHBYTES]; /* partial block */ 62 __le64 partial_words[VMAC_NHBYTES / 8]; 63 }; 64 unsigned int partial_size; /* size of the partial block */ 65 bool first_block_processed; 66 u64 polytmp[2*VMAC_TAG_LEN/64]; /* running total of L2-hash */ 67 union { 68 u8 bytes[VMAC_NONCEBYTES]; 69 __be64 pads[VMAC_NONCEBYTES / 8]; 70 } nonce; 71 unsigned int nonce_size; /* nonce bytes filled so far */ 72 }; 73 74 /* 75 * Constants and masks 76 */ 77 #define UINT64_C(x) x##ULL 78 static const u64 p64 = UINT64_C(0xfffffffffffffeff); /* 2^64 - 257 prime */ 79 static const u64 m62 = UINT64_C(0x3fffffffffffffff); /* 62-bit mask */ 80 static const u64 m63 = UINT64_C(0x7fffffffffffffff); /* 63-bit mask */ 81 static const u64 m64 = UINT64_C(0xffffffffffffffff); /* 64-bit mask */ 82 static const u64 mpoly = UINT64_C(0x1fffffff1fffffff); /* Poly key mask */ 83 84 #define pe64_to_cpup le64_to_cpup /* Prefer little endian */ 85 86 #ifdef __LITTLE_ENDIAN 87 #define INDEX_HIGH 1 88 #define INDEX_LOW 0 89 #else 90 #define INDEX_HIGH 0 91 #define INDEX_LOW 1 92 #endif 93 94 /* 95 * The following routines are used in this implementation. They are 96 * written via macros to simulate zero-overhead call-by-reference. 97 * 98 * MUL64: 64x64->128-bit multiplication 99 * PMUL64: assumes top bits cleared on inputs 100 * ADD128: 128x128->128-bit addition 101 */ 102 103 #define ADD128(rh, rl, ih, il) \ 104 do { \ 105 u64 _il = (il); \ 106 (rl) += (_il); \ 107 if ((rl) < (_il)) \ 108 (rh)++; \ 109 (rh) += (ih); \ 110 } while (0) 111 112 #define MUL32(i1, i2) ((u64)(u32)(i1)*(u32)(i2)) 113 114 #define PMUL64(rh, rl, i1, i2) /* Assumes m doesn't overflow */ \ 115 do { \ 116 u64 _i1 = (i1), _i2 = (i2); \ 117 u64 m = MUL32(_i1, _i2>>32) + MUL32(_i1>>32, _i2); \ 118 rh = MUL32(_i1>>32, _i2>>32); \ 119 rl = MUL32(_i1, _i2); \ 120 ADD128(rh, rl, (m >> 32), (m << 32)); \ 121 } while (0) 122 123 #define MUL64(rh, rl, i1, i2) \ 124 do { \ 125 u64 _i1 = (i1), _i2 = (i2); \ 126 u64 m1 = MUL32(_i1, _i2>>32); \ 127 u64 m2 = MUL32(_i1>>32, _i2); \ 128 rh = MUL32(_i1>>32, _i2>>32); \ 129 rl = MUL32(_i1, _i2); \ 130 ADD128(rh, rl, (m1 >> 32), (m1 << 32)); \ 131 ADD128(rh, rl, (m2 >> 32), (m2 << 32)); \ 132 } while (0) 133 134 /* 135 * For highest performance the L1 NH and L2 polynomial hashes should be 136 * carefully implemented to take advantage of one's target architecture. 137 * Here these two hash functions are defined multiple time; once for 138 * 64-bit architectures, once for 32-bit SSE2 architectures, and once 139 * for the rest (32-bit) architectures. 140 * For each, nh_16 *must* be defined (works on multiples of 16 bytes). 141 * Optionally, nh_vmac_nhbytes can be defined (for multiples of 142 * VMAC_NHBYTES), and nh_16_2 and nh_vmac_nhbytes_2 (versions that do two 143 * NH computations at once). 144 */ 145 146 #ifdef CONFIG_64BIT 147 148 #define nh_16(mp, kp, nw, rh, rl) \ 149 do { \ 150 int i; u64 th, tl; \ 151 rh = rl = 0; \ 152 for (i = 0; i < nw; i += 2) { \ 153 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \ 154 pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \ 155 ADD128(rh, rl, th, tl); \ 156 } \ 157 } while (0) 158 159 #define nh_16_2(mp, kp, nw, rh, rl, rh1, rl1) \ 160 do { \ 161 int i; u64 th, tl; \ 162 rh1 = rl1 = rh = rl = 0; \ 163 for (i = 0; i < nw; i += 2) { \ 164 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \ 165 pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \ 166 ADD128(rh, rl, th, tl); \ 167 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2], \ 168 pe64_to_cpup((mp)+i+1)+(kp)[i+3]); \ 169 ADD128(rh1, rl1, th, tl); \ 170 } \ 171 } while (0) 172 173 #if (VMAC_NHBYTES >= 64) /* These versions do 64-bytes of message at a time */ 174 #define nh_vmac_nhbytes(mp, kp, nw, rh, rl) \ 175 do { \ 176 int i; u64 th, tl; \ 177 rh = rl = 0; \ 178 for (i = 0; i < nw; i += 8) { \ 179 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \ 180 pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \ 181 ADD128(rh, rl, th, tl); \ 182 MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \ 183 pe64_to_cpup((mp)+i+3)+(kp)[i+3]); \ 184 ADD128(rh, rl, th, tl); \ 185 MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \ 186 pe64_to_cpup((mp)+i+5)+(kp)[i+5]); \ 187 ADD128(rh, rl, th, tl); \ 188 MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \ 189 pe64_to_cpup((mp)+i+7)+(kp)[i+7]); \ 190 ADD128(rh, rl, th, tl); \ 191 } \ 192 } while (0) 193 194 #define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh1, rl1) \ 195 do { \ 196 int i; u64 th, tl; \ 197 rh1 = rl1 = rh = rl = 0; \ 198 for (i = 0; i < nw; i += 8) { \ 199 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \ 200 pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \ 201 ADD128(rh, rl, th, tl); \ 202 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2], \ 203 pe64_to_cpup((mp)+i+1)+(kp)[i+3]); \ 204 ADD128(rh1, rl1, th, tl); \ 205 MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \ 206 pe64_to_cpup((mp)+i+3)+(kp)[i+3]); \ 207 ADD128(rh, rl, th, tl); \ 208 MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+4], \ 209 pe64_to_cpup((mp)+i+3)+(kp)[i+5]); \ 210 ADD128(rh1, rl1, th, tl); \ 211 MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \ 212 pe64_to_cpup((mp)+i+5)+(kp)[i+5]); \ 213 ADD128(rh, rl, th, tl); \ 214 MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+6], \ 215 pe64_to_cpup((mp)+i+5)+(kp)[i+7]); \ 216 ADD128(rh1, rl1, th, tl); \ 217 MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \ 218 pe64_to_cpup((mp)+i+7)+(kp)[i+7]); \ 219 ADD128(rh, rl, th, tl); \ 220 MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+8], \ 221 pe64_to_cpup((mp)+i+7)+(kp)[i+9]); \ 222 ADD128(rh1, rl1, th, tl); \ 223 } \ 224 } while (0) 225 #endif 226 227 #define poly_step(ah, al, kh, kl, mh, ml) \ 228 do { \ 229 u64 t1h, t1l, t2h, t2l, t3h, t3l, z = 0; \ 230 /* compute ab*cd, put bd into result registers */ \ 231 PMUL64(t3h, t3l, al, kh); \ 232 PMUL64(t2h, t2l, ah, kl); \ 233 PMUL64(t1h, t1l, ah, 2*kh); \ 234 PMUL64(ah, al, al, kl); \ 235 /* add 2 * ac to result */ \ 236 ADD128(ah, al, t1h, t1l); \ 237 /* add together ad + bc */ \ 238 ADD128(t2h, t2l, t3h, t3l); \ 239 /* now (ah,al), (t2l,2*t2h) need summing */ \ 240 /* first add the high registers, carrying into t2h */ \ 241 ADD128(t2h, ah, z, t2l); \ 242 /* double t2h and add top bit of ah */ \ 243 t2h = 2 * t2h + (ah >> 63); \ 244 ah &= m63; \ 245 /* now add the low registers */ \ 246 ADD128(ah, al, mh, ml); \ 247 ADD128(ah, al, z, t2h); \ 248 } while (0) 249 250 #else /* ! CONFIG_64BIT */ 251 252 #ifndef nh_16 253 #define nh_16(mp, kp, nw, rh, rl) \ 254 do { \ 255 u64 t1, t2, m1, m2, t; \ 256 int i; \ 257 rh = rl = t = 0; \ 258 for (i = 0; i < nw; i += 2) { \ 259 t1 = pe64_to_cpup(mp+i) + kp[i]; \ 260 t2 = pe64_to_cpup(mp+i+1) + kp[i+1]; \ 261 m2 = MUL32(t1 >> 32, t2); \ 262 m1 = MUL32(t1, t2 >> 32); \ 263 ADD128(rh, rl, MUL32(t1 >> 32, t2 >> 32), \ 264 MUL32(t1, t2)); \ 265 rh += (u64)(u32)(m1 >> 32) \ 266 + (u32)(m2 >> 32); \ 267 t += (u64)(u32)m1 + (u32)m2; \ 268 } \ 269 ADD128(rh, rl, (t >> 32), (t << 32)); \ 270 } while (0) 271 #endif 272 273 static void poly_step_func(u64 *ahi, u64 *alo, 274 const u64 *kh, const u64 *kl, 275 const u64 *mh, const u64 *ml) 276 { 277 #define a0 (*(((u32 *)alo)+INDEX_LOW)) 278 #define a1 (*(((u32 *)alo)+INDEX_HIGH)) 279 #define a2 (*(((u32 *)ahi)+INDEX_LOW)) 280 #define a3 (*(((u32 *)ahi)+INDEX_HIGH)) 281 #define k0 (*(((u32 *)kl)+INDEX_LOW)) 282 #define k1 (*(((u32 *)kl)+INDEX_HIGH)) 283 #define k2 (*(((u32 *)kh)+INDEX_LOW)) 284 #define k3 (*(((u32 *)kh)+INDEX_HIGH)) 285 286 u64 p, q, t; 287 u32 t2; 288 289 p = MUL32(a3, k3); 290 p += p; 291 p += *(u64 *)mh; 292 p += MUL32(a0, k2); 293 p += MUL32(a1, k1); 294 p += MUL32(a2, k0); 295 t = (u32)(p); 296 p >>= 32; 297 p += MUL32(a0, k3); 298 p += MUL32(a1, k2); 299 p += MUL32(a2, k1); 300 p += MUL32(a3, k0); 301 t |= ((u64)((u32)p & 0x7fffffff)) << 32; 302 p >>= 31; 303 p += (u64)(((u32 *)ml)[INDEX_LOW]); 304 p += MUL32(a0, k0); 305 q = MUL32(a1, k3); 306 q += MUL32(a2, k2); 307 q += MUL32(a3, k1); 308 q += q; 309 p += q; 310 t2 = (u32)(p); 311 p >>= 32; 312 p += (u64)(((u32 *)ml)[INDEX_HIGH]); 313 p += MUL32(a0, k1); 314 p += MUL32(a1, k0); 315 q = MUL32(a2, k3); 316 q += MUL32(a3, k2); 317 q += q; 318 p += q; 319 *(u64 *)(alo) = (p << 32) | t2; 320 p >>= 32; 321 *(u64 *)(ahi) = p + t; 322 323 #undef a0 324 #undef a1 325 #undef a2 326 #undef a3 327 #undef k0 328 #undef k1 329 #undef k2 330 #undef k3 331 } 332 333 #define poly_step(ah, al, kh, kl, mh, ml) \ 334 poly_step_func(&(ah), &(al), &(kh), &(kl), &(mh), &(ml)) 335 336 #endif /* end of specialized NH and poly definitions */ 337 338 /* At least nh_16 is defined. Defined others as needed here */ 339 #ifndef nh_16_2 340 #define nh_16_2(mp, kp, nw, rh, rl, rh2, rl2) \ 341 do { \ 342 nh_16(mp, kp, nw, rh, rl); \ 343 nh_16(mp, ((kp)+2), nw, rh2, rl2); \ 344 } while (0) 345 #endif 346 #ifndef nh_vmac_nhbytes 347 #define nh_vmac_nhbytes(mp, kp, nw, rh, rl) \ 348 nh_16(mp, kp, nw, rh, rl) 349 #endif 350 #ifndef nh_vmac_nhbytes_2 351 #define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh2, rl2) \ 352 do { \ 353 nh_vmac_nhbytes(mp, kp, nw, rh, rl); \ 354 nh_vmac_nhbytes(mp, ((kp)+2), nw, rh2, rl2); \ 355 } while (0) 356 #endif 357 358 static u64 l3hash(u64 p1, u64 p2, u64 k1, u64 k2, u64 len) 359 { 360 u64 rh, rl, t, z = 0; 361 362 /* fully reduce (p1,p2)+(len,0) mod p127 */ 363 t = p1 >> 63; 364 p1 &= m63; 365 ADD128(p1, p2, len, t); 366 /* At this point, (p1,p2) is at most 2^127+(len<<64) */ 367 t = (p1 > m63) + ((p1 == m63) && (p2 == m64)); 368 ADD128(p1, p2, z, t); 369 p1 &= m63; 370 371 /* compute (p1,p2)/(2^64-2^32) and (p1,p2)%(2^64-2^32) */ 372 t = p1 + (p2 >> 32); 373 t += (t >> 32); 374 t += (u32)t > 0xfffffffeu; 375 p1 += (t >> 32); 376 p2 += (p1 << 32); 377 378 /* compute (p1+k1)%p64 and (p2+k2)%p64 */ 379 p1 += k1; 380 p1 += (0 - (p1 < k1)) & 257; 381 p2 += k2; 382 p2 += (0 - (p2 < k2)) & 257; 383 384 /* compute (p1+k1)*(p2+k2)%p64 */ 385 MUL64(rh, rl, p1, p2); 386 t = rh >> 56; 387 ADD128(t, rl, z, rh); 388 rh <<= 8; 389 ADD128(t, rl, z, rh); 390 t += t << 8; 391 rl += t; 392 rl += (0 - (rl < t)) & 257; 393 rl += (0 - (rl > p64-1)) & 257; 394 return rl; 395 } 396 397 /* L1 and L2-hash one or more VMAC_NHBYTES-byte blocks */ 398 static void vhash_blocks(const struct vmac_tfm_ctx *tctx, 399 struct vmac_desc_ctx *dctx, 400 const __le64 *mptr, unsigned int blocks) 401 { 402 const u64 *kptr = tctx->nhkey; 403 const u64 pkh = tctx->polykey[0]; 404 const u64 pkl = tctx->polykey[1]; 405 u64 ch = dctx->polytmp[0]; 406 u64 cl = dctx->polytmp[1]; 407 u64 rh, rl; 408 409 if (!dctx->first_block_processed) { 410 dctx->first_block_processed = true; 411 nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl); 412 rh &= m62; 413 ADD128(ch, cl, rh, rl); 414 mptr += (VMAC_NHBYTES/sizeof(u64)); 415 blocks--; 416 } 417 418 while (blocks--) { 419 nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl); 420 rh &= m62; 421 poly_step(ch, cl, pkh, pkl, rh, rl); 422 mptr += (VMAC_NHBYTES/sizeof(u64)); 423 } 424 425 dctx->polytmp[0] = ch; 426 dctx->polytmp[1] = cl; 427 } 428 429 static int vmac_setkey(struct crypto_shash *tfm, 430 const u8 *key, unsigned int keylen) 431 { 432 struct vmac_tfm_ctx *tctx = crypto_shash_ctx(tfm); 433 __be64 out[2]; 434 u8 in[16] = { 0 }; 435 unsigned int i; 436 int err; 437 438 if (keylen != VMAC_KEY_LEN) { 439 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); 440 return -EINVAL; 441 } 442 443 err = crypto_cipher_setkey(tctx->cipher, key, keylen); 444 if (err) 445 return err; 446 447 /* Fill nh key */ 448 in[0] = 0x80; 449 for (i = 0; i < ARRAY_SIZE(tctx->nhkey); i += 2) { 450 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in); 451 tctx->nhkey[i] = be64_to_cpu(out[0]); 452 tctx->nhkey[i+1] = be64_to_cpu(out[1]); 453 in[15]++; 454 } 455 456 /* Fill poly key */ 457 in[0] = 0xC0; 458 in[15] = 0; 459 for (i = 0; i < ARRAY_SIZE(tctx->polykey); i += 2) { 460 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in); 461 tctx->polykey[i] = be64_to_cpu(out[0]) & mpoly; 462 tctx->polykey[i+1] = be64_to_cpu(out[1]) & mpoly; 463 in[15]++; 464 } 465 466 /* Fill ip key */ 467 in[0] = 0xE0; 468 in[15] = 0; 469 for (i = 0; i < ARRAY_SIZE(tctx->l3key); i += 2) { 470 do { 471 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in); 472 tctx->l3key[i] = be64_to_cpu(out[0]); 473 tctx->l3key[i+1] = be64_to_cpu(out[1]); 474 in[15]++; 475 } while (tctx->l3key[i] >= p64 || tctx->l3key[i+1] >= p64); 476 } 477 478 return 0; 479 } 480 481 static int vmac_init(struct shash_desc *desc) 482 { 483 const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm); 484 struct vmac_desc_ctx *dctx = shash_desc_ctx(desc); 485 486 dctx->partial_size = 0; 487 dctx->first_block_processed = false; 488 memcpy(dctx->polytmp, tctx->polykey, sizeof(dctx->polytmp)); 489 dctx->nonce_size = 0; 490 return 0; 491 } 492 493 static int vmac_update(struct shash_desc *desc, const u8 *p, unsigned int len) 494 { 495 const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm); 496 struct vmac_desc_ctx *dctx = shash_desc_ctx(desc); 497 unsigned int n; 498 499 /* Nonce is passed as first VMAC_NONCEBYTES bytes of data */ 500 if (dctx->nonce_size < VMAC_NONCEBYTES) { 501 n = min(len, VMAC_NONCEBYTES - dctx->nonce_size); 502 memcpy(&dctx->nonce.bytes[dctx->nonce_size], p, n); 503 dctx->nonce_size += n; 504 p += n; 505 len -= n; 506 } 507 508 if (dctx->partial_size) { 509 n = min(len, VMAC_NHBYTES - dctx->partial_size); 510 memcpy(&dctx->partial[dctx->partial_size], p, n); 511 dctx->partial_size += n; 512 p += n; 513 len -= n; 514 if (dctx->partial_size == VMAC_NHBYTES) { 515 vhash_blocks(tctx, dctx, dctx->partial_words, 1); 516 dctx->partial_size = 0; 517 } 518 } 519 520 if (len >= VMAC_NHBYTES) { 521 n = round_down(len, VMAC_NHBYTES); 522 /* TODO: 'p' may be misaligned here */ 523 vhash_blocks(tctx, dctx, (const __le64 *)p, n / VMAC_NHBYTES); 524 p += n; 525 len -= n; 526 } 527 528 if (len) { 529 memcpy(dctx->partial, p, len); 530 dctx->partial_size = len; 531 } 532 533 return 0; 534 } 535 536 static u64 vhash_final(const struct vmac_tfm_ctx *tctx, 537 struct vmac_desc_ctx *dctx) 538 { 539 unsigned int partial = dctx->partial_size; 540 u64 ch = dctx->polytmp[0]; 541 u64 cl = dctx->polytmp[1]; 542 543 /* L1 and L2-hash the final block if needed */ 544 if (partial) { 545 /* Zero-pad to next 128-bit boundary */ 546 unsigned int n = round_up(partial, 16); 547 u64 rh, rl; 548 549 memset(&dctx->partial[partial], 0, n - partial); 550 nh_16(dctx->partial_words, tctx->nhkey, n / 8, rh, rl); 551 rh &= m62; 552 if (dctx->first_block_processed) 553 poly_step(ch, cl, tctx->polykey[0], tctx->polykey[1], 554 rh, rl); 555 else 556 ADD128(ch, cl, rh, rl); 557 } 558 559 /* L3-hash the 128-bit output of L2-hash */ 560 return l3hash(ch, cl, tctx->l3key[0], tctx->l3key[1], partial * 8); 561 } 562 563 static int vmac_final(struct shash_desc *desc, u8 *out) 564 { 565 const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm); 566 struct vmac_desc_ctx *dctx = shash_desc_ctx(desc); 567 int index; 568 u64 hash, pad; 569 570 if (dctx->nonce_size != VMAC_NONCEBYTES) 571 return -EINVAL; 572 573 /* 574 * The VMAC specification requires a nonce at least 1 bit shorter than 575 * the block cipher's block length, so we actually only accept a 127-bit 576 * nonce. We define the unused bit to be the first one and require that 577 * it be 0, so the needed prepending of a 0 bit is implicit. 578 */ 579 if (dctx->nonce.bytes[0] & 0x80) 580 return -EINVAL; 581 582 /* Finish calculating the VHASH of the message */ 583 hash = vhash_final(tctx, dctx); 584 585 /* Generate pseudorandom pad by encrypting the nonce */ 586 BUILD_BUG_ON(VMAC_NONCEBYTES != 2 * (VMAC_TAG_LEN / 8)); 587 index = dctx->nonce.bytes[VMAC_NONCEBYTES - 1] & 1; 588 dctx->nonce.bytes[VMAC_NONCEBYTES - 1] &= ~1; 589 crypto_cipher_encrypt_one(tctx->cipher, dctx->nonce.bytes, 590 dctx->nonce.bytes); 591 pad = be64_to_cpu(dctx->nonce.pads[index]); 592 593 /* The VMAC is the sum of VHASH and the pseudorandom pad */ 594 put_unaligned_be64(hash + pad, out); 595 return 0; 596 } 597 598 static int vmac_init_tfm(struct crypto_tfm *tfm) 599 { 600 struct crypto_instance *inst = crypto_tfm_alg_instance(tfm); 601 struct crypto_spawn *spawn = crypto_instance_ctx(inst); 602 struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm); 603 struct crypto_cipher *cipher; 604 605 cipher = crypto_spawn_cipher(spawn); 606 if (IS_ERR(cipher)) 607 return PTR_ERR(cipher); 608 609 tctx->cipher = cipher; 610 return 0; 611 } 612 613 static void vmac_exit_tfm(struct crypto_tfm *tfm) 614 { 615 struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm); 616 617 crypto_free_cipher(tctx->cipher); 618 } 619 620 static int vmac_create(struct crypto_template *tmpl, struct rtattr **tb) 621 { 622 struct shash_instance *inst; 623 struct crypto_alg *alg; 624 int err; 625 626 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH); 627 if (err) 628 return err; 629 630 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, 631 CRYPTO_ALG_TYPE_MASK); 632 if (IS_ERR(alg)) 633 return PTR_ERR(alg); 634 635 err = -EINVAL; 636 if (alg->cra_blocksize != VMAC_NONCEBYTES) 637 goto out_put_alg; 638 639 inst = shash_alloc_instance(tmpl->name, alg); 640 err = PTR_ERR(inst); 641 if (IS_ERR(inst)) 642 goto out_put_alg; 643 644 err = crypto_init_spawn(shash_instance_ctx(inst), alg, 645 shash_crypto_instance(inst), 646 CRYPTO_ALG_TYPE_MASK); 647 if (err) 648 goto out_free_inst; 649 650 inst->alg.base.cra_priority = alg->cra_priority; 651 inst->alg.base.cra_blocksize = alg->cra_blocksize; 652 inst->alg.base.cra_alignmask = alg->cra_alignmask; 653 654 inst->alg.base.cra_ctxsize = sizeof(struct vmac_tfm_ctx); 655 inst->alg.base.cra_init = vmac_init_tfm; 656 inst->alg.base.cra_exit = vmac_exit_tfm; 657 658 inst->alg.descsize = sizeof(struct vmac_desc_ctx); 659 inst->alg.digestsize = VMAC_TAG_LEN / 8; 660 inst->alg.init = vmac_init; 661 inst->alg.update = vmac_update; 662 inst->alg.final = vmac_final; 663 inst->alg.setkey = vmac_setkey; 664 665 err = shash_register_instance(tmpl, inst); 666 if (err) { 667 out_free_inst: 668 shash_free_instance(shash_crypto_instance(inst)); 669 } 670 671 out_put_alg: 672 crypto_mod_put(alg); 673 return err; 674 } 675 676 static struct crypto_template vmac64_tmpl = { 677 .name = "vmac64", 678 .create = vmac_create, 679 .free = shash_free_instance, 680 .module = THIS_MODULE, 681 }; 682 683 static int __init vmac_module_init(void) 684 { 685 return crypto_register_template(&vmac64_tmpl); 686 } 687 688 static void __exit vmac_module_exit(void) 689 { 690 crypto_unregister_template(&vmac64_tmpl); 691 } 692 693 subsys_initcall(vmac_module_init); 694 module_exit(vmac_module_exit); 695 696 MODULE_LICENSE("GPL"); 697 MODULE_DESCRIPTION("VMAC hash algorithm"); 698 MODULE_ALIAS_CRYPTO("vmac64"); 699