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 49 /* per-transform (per-key) context */ 50 struct vmac_tfm_ctx { 51 struct crypto_cipher *cipher; 52 u64 nhkey[(VMAC_NHBYTES/8)+2*(VMAC_TAG_LEN/64-1)]; 53 u64 polykey[2*VMAC_TAG_LEN/64]; 54 u64 l3key[2*VMAC_TAG_LEN/64]; 55 }; 56 57 /* per-request context */ 58 struct vmac_desc_ctx { 59 union { 60 u8 partial[VMAC_NHBYTES]; /* partial block */ 61 __le64 partial_words[VMAC_NHBYTES / 8]; 62 }; 63 unsigned int partial_size; /* size of the partial block */ 64 bool first_block_processed; 65 u64 polytmp[2*VMAC_TAG_LEN/64]; /* running total of L2-hash */ 66 }; 67 68 /* 69 * Constants and masks 70 */ 71 #define UINT64_C(x) x##ULL 72 static const u64 p64 = UINT64_C(0xfffffffffffffeff); /* 2^64 - 257 prime */ 73 static const u64 m62 = UINT64_C(0x3fffffffffffffff); /* 62-bit mask */ 74 static const u64 m63 = UINT64_C(0x7fffffffffffffff); /* 63-bit mask */ 75 static const u64 m64 = UINT64_C(0xffffffffffffffff); /* 64-bit mask */ 76 static const u64 mpoly = UINT64_C(0x1fffffff1fffffff); /* Poly key mask */ 77 78 #define pe64_to_cpup le64_to_cpup /* Prefer little endian */ 79 80 #ifdef __LITTLE_ENDIAN 81 #define INDEX_HIGH 1 82 #define INDEX_LOW 0 83 #else 84 #define INDEX_HIGH 0 85 #define INDEX_LOW 1 86 #endif 87 88 /* 89 * The following routines are used in this implementation. They are 90 * written via macros to simulate zero-overhead call-by-reference. 91 * 92 * MUL64: 64x64->128-bit multiplication 93 * PMUL64: assumes top bits cleared on inputs 94 * ADD128: 128x128->128-bit addition 95 */ 96 97 #define ADD128(rh, rl, ih, il) \ 98 do { \ 99 u64 _il = (il); \ 100 (rl) += (_il); \ 101 if ((rl) < (_il)) \ 102 (rh)++; \ 103 (rh) += (ih); \ 104 } while (0) 105 106 #define MUL32(i1, i2) ((u64)(u32)(i1)*(u32)(i2)) 107 108 #define PMUL64(rh, rl, i1, i2) /* Assumes m doesn't overflow */ \ 109 do { \ 110 u64 _i1 = (i1), _i2 = (i2); \ 111 u64 m = MUL32(_i1, _i2>>32) + MUL32(_i1>>32, _i2); \ 112 rh = MUL32(_i1>>32, _i2>>32); \ 113 rl = MUL32(_i1, _i2); \ 114 ADD128(rh, rl, (m >> 32), (m << 32)); \ 115 } while (0) 116 117 #define MUL64(rh, rl, i1, i2) \ 118 do { \ 119 u64 _i1 = (i1), _i2 = (i2); \ 120 u64 m1 = MUL32(_i1, _i2>>32); \ 121 u64 m2 = MUL32(_i1>>32, _i2); \ 122 rh = MUL32(_i1>>32, _i2>>32); \ 123 rl = MUL32(_i1, _i2); \ 124 ADD128(rh, rl, (m1 >> 32), (m1 << 32)); \ 125 ADD128(rh, rl, (m2 >> 32), (m2 << 32)); \ 126 } while (0) 127 128 /* 129 * For highest performance the L1 NH and L2 polynomial hashes should be 130 * carefully implemented to take advantage of one's target architecture. 131 * Here these two hash functions are defined multiple time; once for 132 * 64-bit architectures, once for 32-bit SSE2 architectures, and once 133 * for the rest (32-bit) architectures. 134 * For each, nh_16 *must* be defined (works on multiples of 16 bytes). 135 * Optionally, nh_vmac_nhbytes can be defined (for multiples of 136 * VMAC_NHBYTES), and nh_16_2 and nh_vmac_nhbytes_2 (versions that do two 137 * NH computations at once). 138 */ 139 140 #ifdef CONFIG_64BIT 141 142 #define nh_16(mp, kp, nw, rh, rl) \ 143 do { \ 144 int i; u64 th, tl; \ 145 rh = rl = 0; \ 146 for (i = 0; i < nw; i += 2) { \ 147 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \ 148 pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \ 149 ADD128(rh, rl, th, tl); \ 150 } \ 151 } while (0) 152 153 #define nh_16_2(mp, kp, nw, rh, rl, rh1, rl1) \ 154 do { \ 155 int i; u64 th, tl; \ 156 rh1 = rl1 = rh = rl = 0; \ 157 for (i = 0; i < nw; i += 2) { \ 158 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \ 159 pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \ 160 ADD128(rh, rl, th, tl); \ 161 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2], \ 162 pe64_to_cpup((mp)+i+1)+(kp)[i+3]); \ 163 ADD128(rh1, rl1, th, tl); \ 164 } \ 165 } while (0) 166 167 #if (VMAC_NHBYTES >= 64) /* These versions do 64-bytes of message at a time */ 168 #define nh_vmac_nhbytes(mp, kp, nw, rh, rl) \ 169 do { \ 170 int i; u64 th, tl; \ 171 rh = rl = 0; \ 172 for (i = 0; i < nw; i += 8) { \ 173 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \ 174 pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \ 175 ADD128(rh, rl, th, tl); \ 176 MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \ 177 pe64_to_cpup((mp)+i+3)+(kp)[i+3]); \ 178 ADD128(rh, rl, th, tl); \ 179 MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \ 180 pe64_to_cpup((mp)+i+5)+(kp)[i+5]); \ 181 ADD128(rh, rl, th, tl); \ 182 MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \ 183 pe64_to_cpup((mp)+i+7)+(kp)[i+7]); \ 184 ADD128(rh, rl, th, tl); \ 185 } \ 186 } while (0) 187 188 #define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh1, rl1) \ 189 do { \ 190 int i; u64 th, tl; \ 191 rh1 = rl1 = rh = rl = 0; \ 192 for (i = 0; i < nw; i += 8) { \ 193 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \ 194 pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \ 195 ADD128(rh, rl, th, tl); \ 196 MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2], \ 197 pe64_to_cpup((mp)+i+1)+(kp)[i+3]); \ 198 ADD128(rh1, rl1, th, tl); \ 199 MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \ 200 pe64_to_cpup((mp)+i+3)+(kp)[i+3]); \ 201 ADD128(rh, rl, th, tl); \ 202 MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+4], \ 203 pe64_to_cpup((mp)+i+3)+(kp)[i+5]); \ 204 ADD128(rh1, rl1, th, tl); \ 205 MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \ 206 pe64_to_cpup((mp)+i+5)+(kp)[i+5]); \ 207 ADD128(rh, rl, th, tl); \ 208 MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+6], \ 209 pe64_to_cpup((mp)+i+5)+(kp)[i+7]); \ 210 ADD128(rh1, rl1, th, tl); \ 211 MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \ 212 pe64_to_cpup((mp)+i+7)+(kp)[i+7]); \ 213 ADD128(rh, rl, th, tl); \ 214 MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+8], \ 215 pe64_to_cpup((mp)+i+7)+(kp)[i+9]); \ 216 ADD128(rh1, rl1, th, tl); \ 217 } \ 218 } while (0) 219 #endif 220 221 #define poly_step(ah, al, kh, kl, mh, ml) \ 222 do { \ 223 u64 t1h, t1l, t2h, t2l, t3h, t3l, z = 0; \ 224 /* compute ab*cd, put bd into result registers */ \ 225 PMUL64(t3h, t3l, al, kh); \ 226 PMUL64(t2h, t2l, ah, kl); \ 227 PMUL64(t1h, t1l, ah, 2*kh); \ 228 PMUL64(ah, al, al, kl); \ 229 /* add 2 * ac to result */ \ 230 ADD128(ah, al, t1h, t1l); \ 231 /* add together ad + bc */ \ 232 ADD128(t2h, t2l, t3h, t3l); \ 233 /* now (ah,al), (t2l,2*t2h) need summing */ \ 234 /* first add the high registers, carrying into t2h */ \ 235 ADD128(t2h, ah, z, t2l); \ 236 /* double t2h and add top bit of ah */ \ 237 t2h = 2 * t2h + (ah >> 63); \ 238 ah &= m63; \ 239 /* now add the low registers */ \ 240 ADD128(ah, al, mh, ml); \ 241 ADD128(ah, al, z, t2h); \ 242 } while (0) 243 244 #else /* ! CONFIG_64BIT */ 245 246 #ifndef nh_16 247 #define nh_16(mp, kp, nw, rh, rl) \ 248 do { \ 249 u64 t1, t2, m1, m2, t; \ 250 int i; \ 251 rh = rl = t = 0; \ 252 for (i = 0; i < nw; i += 2) { \ 253 t1 = pe64_to_cpup(mp+i) + kp[i]; \ 254 t2 = pe64_to_cpup(mp+i+1) + kp[i+1]; \ 255 m2 = MUL32(t1 >> 32, t2); \ 256 m1 = MUL32(t1, t2 >> 32); \ 257 ADD128(rh, rl, MUL32(t1 >> 32, t2 >> 32), \ 258 MUL32(t1, t2)); \ 259 rh += (u64)(u32)(m1 >> 32) \ 260 + (u32)(m2 >> 32); \ 261 t += (u64)(u32)m1 + (u32)m2; \ 262 } \ 263 ADD128(rh, rl, (t >> 32), (t << 32)); \ 264 } while (0) 265 #endif 266 267 static void poly_step_func(u64 *ahi, u64 *alo, 268 const u64 *kh, const u64 *kl, 269 const u64 *mh, const u64 *ml) 270 { 271 #define a0 (*(((u32 *)alo)+INDEX_LOW)) 272 #define a1 (*(((u32 *)alo)+INDEX_HIGH)) 273 #define a2 (*(((u32 *)ahi)+INDEX_LOW)) 274 #define a3 (*(((u32 *)ahi)+INDEX_HIGH)) 275 #define k0 (*(((u32 *)kl)+INDEX_LOW)) 276 #define k1 (*(((u32 *)kl)+INDEX_HIGH)) 277 #define k2 (*(((u32 *)kh)+INDEX_LOW)) 278 #define k3 (*(((u32 *)kh)+INDEX_HIGH)) 279 280 u64 p, q, t; 281 u32 t2; 282 283 p = MUL32(a3, k3); 284 p += p; 285 p += *(u64 *)mh; 286 p += MUL32(a0, k2); 287 p += MUL32(a1, k1); 288 p += MUL32(a2, k0); 289 t = (u32)(p); 290 p >>= 32; 291 p += MUL32(a0, k3); 292 p += MUL32(a1, k2); 293 p += MUL32(a2, k1); 294 p += MUL32(a3, k0); 295 t |= ((u64)((u32)p & 0x7fffffff)) << 32; 296 p >>= 31; 297 p += (u64)(((u32 *)ml)[INDEX_LOW]); 298 p += MUL32(a0, k0); 299 q = MUL32(a1, k3); 300 q += MUL32(a2, k2); 301 q += MUL32(a3, k1); 302 q += q; 303 p += q; 304 t2 = (u32)(p); 305 p >>= 32; 306 p += (u64)(((u32 *)ml)[INDEX_HIGH]); 307 p += MUL32(a0, k1); 308 p += MUL32(a1, k0); 309 q = MUL32(a2, k3); 310 q += MUL32(a3, k2); 311 q += q; 312 p += q; 313 *(u64 *)(alo) = (p << 32) | t2; 314 p >>= 32; 315 *(u64 *)(ahi) = p + t; 316 317 #undef a0 318 #undef a1 319 #undef a2 320 #undef a3 321 #undef k0 322 #undef k1 323 #undef k2 324 #undef k3 325 } 326 327 #define poly_step(ah, al, kh, kl, mh, ml) \ 328 poly_step_func(&(ah), &(al), &(kh), &(kl), &(mh), &(ml)) 329 330 #endif /* end of specialized NH and poly definitions */ 331 332 /* At least nh_16 is defined. Defined others as needed here */ 333 #ifndef nh_16_2 334 #define nh_16_2(mp, kp, nw, rh, rl, rh2, rl2) \ 335 do { \ 336 nh_16(mp, kp, nw, rh, rl); \ 337 nh_16(mp, ((kp)+2), nw, rh2, rl2); \ 338 } while (0) 339 #endif 340 #ifndef nh_vmac_nhbytes 341 #define nh_vmac_nhbytes(mp, kp, nw, rh, rl) \ 342 nh_16(mp, kp, nw, rh, rl) 343 #endif 344 #ifndef nh_vmac_nhbytes_2 345 #define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh2, rl2) \ 346 do { \ 347 nh_vmac_nhbytes(mp, kp, nw, rh, rl); \ 348 nh_vmac_nhbytes(mp, ((kp)+2), nw, rh2, rl2); \ 349 } while (0) 350 #endif 351 352 static u64 l3hash(u64 p1, u64 p2, u64 k1, u64 k2, u64 len) 353 { 354 u64 rh, rl, t, z = 0; 355 356 /* fully reduce (p1,p2)+(len,0) mod p127 */ 357 t = p1 >> 63; 358 p1 &= m63; 359 ADD128(p1, p2, len, t); 360 /* At this point, (p1,p2) is at most 2^127+(len<<64) */ 361 t = (p1 > m63) + ((p1 == m63) && (p2 == m64)); 362 ADD128(p1, p2, z, t); 363 p1 &= m63; 364 365 /* compute (p1,p2)/(2^64-2^32) and (p1,p2)%(2^64-2^32) */ 366 t = p1 + (p2 >> 32); 367 t += (t >> 32); 368 t += (u32)t > 0xfffffffeu; 369 p1 += (t >> 32); 370 p2 += (p1 << 32); 371 372 /* compute (p1+k1)%p64 and (p2+k2)%p64 */ 373 p1 += k1; 374 p1 += (0 - (p1 < k1)) & 257; 375 p2 += k2; 376 p2 += (0 - (p2 < k2)) & 257; 377 378 /* compute (p1+k1)*(p2+k2)%p64 */ 379 MUL64(rh, rl, p1, p2); 380 t = rh >> 56; 381 ADD128(t, rl, z, rh); 382 rh <<= 8; 383 ADD128(t, rl, z, rh); 384 t += t << 8; 385 rl += t; 386 rl += (0 - (rl < t)) & 257; 387 rl += (0 - (rl > p64-1)) & 257; 388 return rl; 389 } 390 391 /* L1 and L2-hash one or more VMAC_NHBYTES-byte blocks */ 392 static void vhash_blocks(const struct vmac_tfm_ctx *tctx, 393 struct vmac_desc_ctx *dctx, 394 const __le64 *mptr, unsigned int blocks) 395 { 396 const u64 *kptr = tctx->nhkey; 397 const u64 pkh = tctx->polykey[0]; 398 const u64 pkl = tctx->polykey[1]; 399 u64 ch = dctx->polytmp[0]; 400 u64 cl = dctx->polytmp[1]; 401 u64 rh, rl; 402 403 if (!dctx->first_block_processed) { 404 dctx->first_block_processed = true; 405 nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl); 406 rh &= m62; 407 ADD128(ch, cl, rh, rl); 408 mptr += (VMAC_NHBYTES/sizeof(u64)); 409 blocks--; 410 } 411 412 while (blocks--) { 413 nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl); 414 rh &= m62; 415 poly_step(ch, cl, pkh, pkl, rh, rl); 416 mptr += (VMAC_NHBYTES/sizeof(u64)); 417 } 418 419 dctx->polytmp[0] = ch; 420 dctx->polytmp[1] = cl; 421 } 422 423 static int vmac_setkey(struct crypto_shash *tfm, 424 const u8 *key, unsigned int keylen) 425 { 426 struct vmac_tfm_ctx *tctx = crypto_shash_ctx(tfm); 427 __be64 out[2]; 428 u8 in[16] = { 0 }; 429 unsigned int i; 430 int err; 431 432 if (keylen != VMAC_KEY_LEN) { 433 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); 434 return -EINVAL; 435 } 436 437 err = crypto_cipher_setkey(tctx->cipher, key, keylen); 438 if (err) 439 return err; 440 441 /* Fill nh key */ 442 in[0] = 0x80; 443 for (i = 0; i < ARRAY_SIZE(tctx->nhkey); i += 2) { 444 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in); 445 tctx->nhkey[i] = be64_to_cpu(out[0]); 446 tctx->nhkey[i+1] = be64_to_cpu(out[1]); 447 in[15]++; 448 } 449 450 /* Fill poly key */ 451 in[0] = 0xC0; 452 in[15] = 0; 453 for (i = 0; i < ARRAY_SIZE(tctx->polykey); i += 2) { 454 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in); 455 tctx->polykey[i] = be64_to_cpu(out[0]) & mpoly; 456 tctx->polykey[i+1] = be64_to_cpu(out[1]) & mpoly; 457 in[15]++; 458 } 459 460 /* Fill ip key */ 461 in[0] = 0xE0; 462 in[15] = 0; 463 for (i = 0; i < ARRAY_SIZE(tctx->l3key); i += 2) { 464 do { 465 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in); 466 tctx->l3key[i] = be64_to_cpu(out[0]); 467 tctx->l3key[i+1] = be64_to_cpu(out[1]); 468 in[15]++; 469 } while (tctx->l3key[i] >= p64 || tctx->l3key[i+1] >= p64); 470 } 471 472 return 0; 473 } 474 475 static int vmac_init(struct shash_desc *desc) 476 { 477 const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm); 478 struct vmac_desc_ctx *dctx = shash_desc_ctx(desc); 479 480 dctx->partial_size = 0; 481 dctx->first_block_processed = false; 482 memcpy(dctx->polytmp, tctx->polykey, sizeof(dctx->polytmp)); 483 return 0; 484 } 485 486 static int vmac_update(struct shash_desc *desc, const u8 *p, unsigned int len) 487 { 488 const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm); 489 struct vmac_desc_ctx *dctx = shash_desc_ctx(desc); 490 unsigned int n; 491 492 if (dctx->partial_size) { 493 n = min(len, VMAC_NHBYTES - dctx->partial_size); 494 memcpy(&dctx->partial[dctx->partial_size], p, n); 495 dctx->partial_size += n; 496 p += n; 497 len -= n; 498 if (dctx->partial_size == VMAC_NHBYTES) { 499 vhash_blocks(tctx, dctx, dctx->partial_words, 1); 500 dctx->partial_size = 0; 501 } 502 } 503 504 if (len >= VMAC_NHBYTES) { 505 n = round_down(len, VMAC_NHBYTES); 506 /* TODO: 'p' may be misaligned here */ 507 vhash_blocks(tctx, dctx, (const __le64 *)p, n / VMAC_NHBYTES); 508 p += n; 509 len -= n; 510 } 511 512 if (len) { 513 memcpy(dctx->partial, p, len); 514 dctx->partial_size = len; 515 } 516 517 return 0; 518 } 519 520 static u64 vhash_final(const struct vmac_tfm_ctx *tctx, 521 struct vmac_desc_ctx *dctx) 522 { 523 unsigned int partial = dctx->partial_size; 524 u64 ch = dctx->polytmp[0]; 525 u64 cl = dctx->polytmp[1]; 526 527 /* L1 and L2-hash the final block if needed */ 528 if (partial) { 529 /* Zero-pad to next 128-bit boundary */ 530 unsigned int n = round_up(partial, 16); 531 u64 rh, rl; 532 533 memset(&dctx->partial[partial], 0, n - partial); 534 nh_16(dctx->partial_words, tctx->nhkey, n / 8, rh, rl); 535 rh &= m62; 536 if (dctx->first_block_processed) 537 poly_step(ch, cl, tctx->polykey[0], tctx->polykey[1], 538 rh, rl); 539 else 540 ADD128(ch, cl, rh, rl); 541 } 542 543 /* L3-hash the 128-bit output of L2-hash */ 544 return l3hash(ch, cl, tctx->l3key[0], tctx->l3key[1], partial * 8); 545 } 546 547 static int vmac_final(struct shash_desc *desc, u8 *out) 548 { 549 const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm); 550 struct vmac_desc_ctx *dctx = shash_desc_ctx(desc); 551 static const u8 nonce[16] = {}; /* TODO: this is insecure */ 552 union { 553 u8 bytes[16]; 554 __be64 pads[2]; 555 } block; 556 int index; 557 u64 hash, pad; 558 559 /* Finish calculating the VHASH of the message */ 560 hash = vhash_final(tctx, dctx); 561 562 /* Generate pseudorandom pad by encrypting the nonce */ 563 memcpy(&block, nonce, 16); 564 index = block.bytes[15] & 1; 565 block.bytes[15] &= ~1; 566 crypto_cipher_encrypt_one(tctx->cipher, block.bytes, block.bytes); 567 pad = be64_to_cpu(block.pads[index]); 568 569 /* The VMAC is the sum of VHASH and the pseudorandom pad */ 570 put_unaligned_le64(hash + pad, out); 571 return 0; 572 } 573 574 static int vmac_init_tfm(struct crypto_tfm *tfm) 575 { 576 struct crypto_instance *inst = crypto_tfm_alg_instance(tfm); 577 struct crypto_spawn *spawn = crypto_instance_ctx(inst); 578 struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm); 579 struct crypto_cipher *cipher; 580 581 cipher = crypto_spawn_cipher(spawn); 582 if (IS_ERR(cipher)) 583 return PTR_ERR(cipher); 584 585 tctx->cipher = cipher; 586 return 0; 587 } 588 589 static void vmac_exit_tfm(struct crypto_tfm *tfm) 590 { 591 struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm); 592 593 crypto_free_cipher(tctx->cipher); 594 } 595 596 static int vmac_create(struct crypto_template *tmpl, struct rtattr **tb) 597 { 598 struct shash_instance *inst; 599 struct crypto_alg *alg; 600 int err; 601 602 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH); 603 if (err) 604 return err; 605 606 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, 607 CRYPTO_ALG_TYPE_MASK); 608 if (IS_ERR(alg)) 609 return PTR_ERR(alg); 610 611 err = -EINVAL; 612 if (alg->cra_blocksize != 16) 613 goto out_put_alg; 614 615 inst = shash_alloc_instance("vmac", alg); 616 err = PTR_ERR(inst); 617 if (IS_ERR(inst)) 618 goto out_put_alg; 619 620 err = crypto_init_spawn(shash_instance_ctx(inst), alg, 621 shash_crypto_instance(inst), 622 CRYPTO_ALG_TYPE_MASK); 623 if (err) 624 goto out_free_inst; 625 626 inst->alg.base.cra_priority = alg->cra_priority; 627 inst->alg.base.cra_blocksize = alg->cra_blocksize; 628 inst->alg.base.cra_alignmask = alg->cra_alignmask; 629 630 inst->alg.base.cra_ctxsize = sizeof(struct vmac_tfm_ctx); 631 inst->alg.base.cra_init = vmac_init_tfm; 632 inst->alg.base.cra_exit = vmac_exit_tfm; 633 634 inst->alg.descsize = sizeof(struct vmac_desc_ctx); 635 inst->alg.digestsize = VMAC_TAG_LEN / 8; 636 inst->alg.init = vmac_init; 637 inst->alg.update = vmac_update; 638 inst->alg.final = vmac_final; 639 inst->alg.setkey = vmac_setkey; 640 641 err = shash_register_instance(tmpl, inst); 642 if (err) { 643 out_free_inst: 644 shash_free_instance(shash_crypto_instance(inst)); 645 } 646 647 out_put_alg: 648 crypto_mod_put(alg); 649 return err; 650 } 651 652 static struct crypto_template vmac_tmpl = { 653 .name = "vmac", 654 .create = vmac_create, 655 .free = shash_free_instance, 656 .module = THIS_MODULE, 657 }; 658 659 static int __init vmac_module_init(void) 660 { 661 return crypto_register_template(&vmac_tmpl); 662 } 663 664 static void __exit vmac_module_exit(void) 665 { 666 crypto_unregister_template(&vmac_tmpl); 667 } 668 669 module_init(vmac_module_init); 670 module_exit(vmac_module_exit); 671 672 MODULE_LICENSE("GPL"); 673 MODULE_DESCRIPTION("VMAC hash algorithm"); 674 MODULE_ALIAS_CRYPTO("vmac"); 675