lib/sha256.c

   1 /*-
   2  * Copyright 2005,2007,2009 Colin Percival
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <zebra.h>
  28 #include "sha256.h"
  29
  30 #if !HAVE_DECL_BE32DEC
  31 static inline uint32_t be32dec(const void *pp)
  32 {
  33         const uint8_t *p = (uint8_t const *)pp;
  34
  35         return ((uint32_t)(p[3]) + ((uint32_t)(p[2]) << 8)
  36                 + ((uint32_t)(p[1]) << 16) + ((uint32_t)(p[0]) << 24));
  37 }
  38 #else
  39 #include <sys/endian.h>
  40 #endif
  41
  42 #if !HAVE_DECL_BE32ENC
  43 static inline void be32enc(void *pp, uint32_t x)
  44 {
  45         uint8_t *p = (uint8_t *)pp;
  46
  47         p[3] = x & 0xff;
  48         p[2] = (x >> 8) & 0xff;
  49         p[1] = (x >> 16) & 0xff;
  50         p[0] = (x >> 24) & 0xff;
  51 }
  52 #else
  53 #include <sys/endian.h>
  54 #endif
  55
  56 /*
  57  * Encode a length len/4 vector of (uint32_t) into a length len vector of
  58  * (unsigned char) in big-endian form.  Assumes len is a multiple of 4.
  59  */
  60 static void be32enc_vect(unsigned char *dst, const uint32_t *src, size_t len)
  61 {
  62         size_t i;
  63
  64         for (i = 0; i < len / 4; i++)
  65                 be32enc(dst + i * 4, src[i]);
  66 }
  67
  68 /*
  69  * Decode a big-endian length len vector of (unsigned char) into a length
  70  * len/4 vector of (uint32_t).  Assumes len is a multiple of 4.
  71  */
  72 static void be32dec_vect(uint32_t *dst, const unsigned char *src, size_t len)
  73 {
  74         size_t i;
  75
  76         for (i = 0; i < len / 4; i++)
  77                 dst[i] = be32dec(src + i * 4);
  78 }
  79
  80 /* Elementary functions used by SHA256 */
  81 #define Ch(x, y, z)     ((x & (y ^ z)) ^ z)
  82 #define Maj(x, y, z)    ((x & (y | z)) | (y & z))
  83 #define SHR(x, n)       (x >> n)
  84 #define ROTR(x, n)      ((x >> n) | (x << (32 - n)))
  85 #define S0(x)           (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
  86 #define S1(x)           (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
  87 #define s0(x)           (ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3))
  88 #define s1(x)           (ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10))
  89
  90 /* SHA256 round function */
  91 #define RND(a, b, c, d, e, f, g, h, k)                                         \
  92         t0 = h + S1(e) + Ch(e, f, g) + k;                                      \
  93         t1 = S0(a) + Maj(a, b, c);                                             \
  94         d += t0;                                                               \
  95         h = t0 + t1;
  96
  97 /* Adjusted round function for rotating state */
  98 #define RNDr(S, W, i, k)                                                       \
  99         RND(S[(64 - i) % 8], S[(65 - i) % 8], S[(66 - i) % 8],                 \
 100             S[(67 - i) % 8], S[(68 - i) % 8], S[(69 - i) % 8],                 \
 101             S[(70 - i) % 8], S[(71 - i) % 8], W[i] + k)
 102
 103 /*
 104  * SHA256 block compression function.  The 256-bit state is transformed via
 105  * the 512-bit input block to produce a new state.
 106  */
 107 static void SHA256_Transform(uint32_t *state, const unsigned char block[64])
 108 {
 109         uint32_t W[64];
 110         uint32_t S[8];
 111         uint32_t t0, t1;
 112         int i;
 113
 114         /* 1. Prepare message schedule W. */
 115         be32dec_vect(W, block, 64);
 116         for (i = 16; i < 64; i++)
 117                 W[i] = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16];
 118
 119         /* 2. Initialize working variables. */
 120         memcpy(S, state, 32);
 121
 122         /* 3. Mix. */
 123         RNDr(S, W, 0, 0x428a2f98);
 124         RNDr(S, W, 1, 0x71374491);
 125         RNDr(S, W, 2, 0xb5c0fbcf);
 126         RNDr(S, W, 3, 0xe9b5dba5);
 127         RNDr(S, W, 4, 0x3956c25b);
 128         RNDr(S, W, 5, 0x59f111f1);
 129         RNDr(S, W, 6, 0x923f82a4);
 130         RNDr(S, W, 7, 0xab1c5ed5);
 131         RNDr(S, W, 8, 0xd807aa98);
 132         RNDr(S, W, 9, 0x12835b01);
 133         RNDr(S, W, 10, 0x243185be);
 134         RNDr(S, W, 11, 0x550c7dc3);
 135         RNDr(S, W, 12, 0x72be5d74);
 136         RNDr(S, W, 13, 0x80deb1fe);
 137         RNDr(S, W, 14, 0x9bdc06a7);
 138         RNDr(S, W, 15, 0xc19bf174);
 139         RNDr(S, W, 16, 0xe49b69c1);
 140         RNDr(S, W, 17, 0xefbe4786);
 141         RNDr(S, W, 18, 0x0fc19dc6);
 142         RNDr(S, W, 19, 0x240ca1cc);
 143         RNDr(S, W, 20, 0x2de92c6f);
 144         RNDr(S, W, 21, 0x4a7484aa);
 145         RNDr(S, W, 22, 0x5cb0a9dc);
 146         RNDr(S, W, 23, 0x76f988da);
 147         RNDr(S, W, 24, 0x983e5152);
 148         RNDr(S, W, 25, 0xa831c66d);
 149         RNDr(S, W, 26, 0xb00327c8);
 150         RNDr(S, W, 27, 0xbf597fc7);
 151         RNDr(S, W, 28, 0xc6e00bf3);
 152         RNDr(S, W, 29, 0xd5a79147);
 153         RNDr(S, W, 30, 0x06ca6351);
 154         RNDr(S, W, 31, 0x14292967);
 155         RNDr(S, W, 32, 0x27b70a85);
 156         RNDr(S, W, 33, 0x2e1b2138);
 157         RNDr(S, W, 34, 0x4d2c6dfc);
 158         RNDr(S, W, 35, 0x53380d13);
 159         RNDr(S, W, 36, 0x650a7354);
 160         RNDr(S, W, 37, 0x766a0abb);
 161         RNDr(S, W, 38, 0x81c2c92e);
 162         RNDr(S, W, 39, 0x92722c85);
 163         RNDr(S, W, 40, 0xa2bfe8a1);
 164         RNDr(S, W, 41, 0xa81a664b);
 165         RNDr(S, W, 42, 0xc24b8b70);
 166         RNDr(S, W, 43, 0xc76c51a3);
 167         RNDr(S, W, 44, 0xd192e819);
 168         RNDr(S, W, 45, 0xd6990624);
 169         RNDr(S, W, 46, 0xf40e3585);
 170         RNDr(S, W, 47, 0x106aa070);
 171         RNDr(S, W, 48, 0x19a4c116);
 172         RNDr(S, W, 49, 0x1e376c08);
 173         RNDr(S, W, 50, 0x2748774c);
 174         RNDr(S, W, 51, 0x34b0bcb5);
 175         RNDr(S, W, 52, 0x391c0cb3);
 176         RNDr(S, W, 53, 0x4ed8aa4a);
 177         RNDr(S, W, 54, 0x5b9cca4f);
 178         RNDr(S, W, 55, 0x682e6ff3);
 179         RNDr(S, W, 56, 0x748f82ee);
 180         RNDr(S, W, 57, 0x78a5636f);
 181         RNDr(S, W, 58, 0x84c87814);
 182         RNDr(S, W, 59, 0x8cc70208);
 183         RNDr(S, W, 60, 0x90befffa);
 184         RNDr(S, W, 61, 0xa4506ceb);
 185         RNDr(S, W, 62, 0xbef9a3f7);
 186         RNDr(S, W, 63, 0xc67178f2);
 187
 188         /* 4. Mix local working variables into global state */
 189         for (i = 0; i < 8; i++)
 190                 state[i] += S[i];
 191
 192         /* Clean the stack. */
 193         memset(W, 0, 256);
 194         memset(S, 0, 32);
 195         t0 = t1 = 0;
 196 }
 197
 198 static unsigned char PAD[64] = {
 199         0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 200         0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 201         0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 202
 203 /* Add padding and terminating bit-count. */
 204 static void SHA256_Pad(SHA256_CTX *ctx)
 205 {
 206         unsigned char len[8];
 207         uint32_t r, plen;
 208
 209         /*
 210          * Convert length to a vector of bytes -- we do this now rather
 211          * than later because the length will change after we pad.
 212          */
 213         be32enc_vect(len, ctx->count, 8);
 214
 215         /* Add 1--64 bytes so that the resulting length is 56 mod 64 */
 216         r = (ctx->count[1] >> 3) & 0x3f;
 217         plen = (r < 56) ? (56 - r) : (120 - r);
 218         SHA256_Update(ctx, PAD, (size_t)plen);
 219
 220         /* Add the terminating bit-count */
 221         SHA256_Update(ctx, len, 8);
 222 }
 223
 224 /* SHA-256 initialization.  Begins a SHA-256 operation. */
 225 void SHA256_Init(SHA256_CTX *ctx)
 226 {
 227
 228         /* Zero bits processed so far */
 229         ctx->count[0] = ctx->count[1] = 0;
 230
 231         /* Magic initialization constants */
 232         ctx->state[0] = 0x6A09E667;
 233         ctx->state[1] = 0xBB67AE85;
 234         ctx->state[2] = 0x3C6EF372;
 235         ctx->state[3] = 0xA54FF53A;
 236         ctx->state[4] = 0x510E527F;
 237         ctx->state[5] = 0x9B05688C;
 238         ctx->state[6] = 0x1F83D9AB;
 239         ctx->state[7] = 0x5BE0CD19;
 240 }
 241
 242 /* Add bytes into the hash */
 243 void SHA256_Update(SHA256_CTX *ctx, const void *in, size_t len)
 244 {
 245         uint32_t bitlen[2];
 246         uint32_t r;
 247         const unsigned char *src = in;
 248
 249         /* Number of bytes left in the buffer from previous updates */
 250         r = (ctx->count[1] >> 3) & 0x3f;
 251
 252         /* Convert the length into a number of bits */
 253         bitlen[1] = ((uint32_t)len) << 3;
 254         bitlen[0] = (uint32_t)(len >> 29);
 255
 256         /* Update number of bits */
 257         if ((ctx->count[1] += bitlen[1]) < bitlen[1])
 258                 ctx->count[0]++;
 259         ctx->count[0] += bitlen[0];
 260
 261         /* Handle the case where we don't need to perform any transforms */
 262         if (len < 64 - r) {
 263                 memcpy(&ctx->buf[r], src, len);
 264                 return;
 265         }
 266
 267         /* Finish the current block */
 268         memcpy(&ctx->buf[r], src, 64 - r);
 269         SHA256_Transform(ctx->state, ctx->buf);
 270         src += 64 - r;
 271         len -= 64 - r;
 272
 273         /* Perform complete blocks */
 274         while (len >= 64) {
 275                 SHA256_Transform(ctx->state, src);
 276                 src += 64;
 277                 len -= 64;
 278         }
 279
 280         /* Copy left over data into buffer */
 281         memcpy(ctx->buf, src, len);
 282 }
 283
 284 /*
 285  * SHA-256 finalization.  Pads the input data, exports the hash value,
 286  * and clears the context state.
 287  */
 288 void SHA256_Final(unsigned char digest[32], SHA256_CTX *ctx)
 289 {
 290
 291         /* Add padding */
 292         SHA256_Pad(ctx);
 293
 294         /* Write the hash */
 295         be32enc_vect(digest, ctx->state, 32);
 296
 297         /* Clear the context state */
 298         memset((void *)ctx, 0, sizeof(*ctx));
 299 }
 300
 301 /* Initialize an HMAC-SHA256 operation with the given key. */
 302 void HMAC__SHA256_Init(HMAC_SHA256_CTX *ctx, const void *_K, size_t Klen)
 303 {
 304         unsigned char pad[64];
 305         unsigned char khash[32];
 306         const unsigned char *K = _K;
 307         size_t i;
 308
 309         /* If Klen > 64, the key is really SHA256(K). */
 310         if (Klen > 64) {
 311                 SHA256_Init(&ctx->ictx);
 312                 SHA256_Update(&ctx->ictx, K, Klen);
 313                 SHA256_Final(khash, &ctx->ictx);
 314                 K = khash;
 315                 Klen = 32;
 316         }
 317
 318         /* Inner SHA256 operation is SHA256(K xor [block of 0x36] || data). */
 319         SHA256_Init(&ctx->ictx);
 320         memset(pad, 0x36, 64);
 321         for (i = 0; i < Klen; i++)
 322                 pad[i] ^= K[i];
 323         SHA256_Update(&ctx->ictx, pad, 64);
 324
 325         /* Outer SHA256 operation is SHA256(K xor [block of 0x5c] || hash). */
 326         SHA256_Init(&ctx->octx);
 327         memset(pad, 0x5c, 64);
 328         for (i = 0; i < Klen; i++)
 329                 pad[i] ^= K[i];
 330         SHA256_Update(&ctx->octx, pad, 64);
 331
 332         /* Clean the stack. */
 333         memset(khash, 0, 32);
 334 }
 335
 336 /* Add bytes to the HMAC-SHA256 operation. */
 337 void HMAC__SHA256_Update(HMAC_SHA256_CTX *ctx, const void *in, size_t len)
 338 {
 339
 340         /* Feed data to the inner SHA256 operation. */
 341         SHA256_Update(&ctx->ictx, in, len);
 342 }
 343
 344 /* Finish an HMAC-SHA256 operation. */
 345 void HMAC__SHA256_Final(unsigned char digest[32], HMAC_SHA256_CTX *ctx)
 346 {
 347         unsigned char ihash[32];
 348
 349         /* Finish the inner SHA256 operation. */
 350         SHA256_Final(ihash, &ctx->ictx);
 351
 352         /* Feed the inner hash to the outer SHA256 operation. */
 353         SHA256_Update(&ctx->octx, ihash, 32);
 354
 355         /* Finish the outer SHA256 operation. */
 356         SHA256_Final(digest, &ctx->octx);
 357
 358         /* Clean the stack. */
 359         memset(ihash, 0, 32);
 360 }
 361
 362 /**
 363  * PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, c, buf, dkLen):
 364  * Compute PBKDF2(passwd, salt, c, dkLen) using HMAC-SHA256 as the PRF, and
 365  * write the output to buf.  The value dkLen must be at most 32 * (2^32 - 1).
 366  */
 367 void PBKDF2_SHA256(const uint8_t *passwd, size_t passwdlen, const uint8_t *salt,
 368                    size_t saltlen, uint64_t c, uint8_t *buf, size_t dkLen)
 369 {
 370         HMAC_SHA256_CTX PShctx, hctx;
 371         size_t i;
 372         uint8_t ivec[4];
 373         uint8_t U[32];
 374         uint8_t T[32];
 375         uint64_t j;
 376         int k;
 377         size_t clen;
 378
 379         /* Compute HMAC state after processing P and S. */
 380         HMAC__SHA256_Init(&PShctx, passwd, passwdlen);
 381         HMAC__SHA256_Update(&PShctx, salt, saltlen);
 382
 383         /* Iterate through the blocks. */
 384         for (i = 0; i * 32 < dkLen; i++) {
 385                 /* Generate INT(i + 1). */
 386                 be32enc(ivec, (uint32_t)(i + 1));
 387
 388                 /* Compute U_1 = PRF(P, S || INT(i)). */
 389                 memcpy(&hctx, &PShctx, sizeof(HMAC_SHA256_CTX));
 390                 HMAC__SHA256_Update(&hctx, ivec, 4);
 391                 HMAC__SHA256_Final(U, &hctx);
 392
 393                 /* T_i = U_1 ... */
 394                 memcpy(T, U, 32);
 395
 396                 for (j = 2; j <= c; j++) {
 397                         /* Compute U_j. */
 398                         HMAC__SHA256_Init(&hctx, passwd, passwdlen);
 399                         HMAC__SHA256_Update(&hctx, U, 32);
 400                         HMAC__SHA256_Final(U, &hctx);
 401
 402                         /* ... xor U_j ... */
 403                         for (k = 0; k < 32; k++)
 404                                 T[k] ^= U[k];
 405                 }
 406
 407                 /* Copy as many bytes as necessary into buf. */
 408                 clen = dkLen - i * 32;
 409                 if (clen > 32)
 410                         clen = 32;
 411                 memcpy(&buf[i * 32], T, clen);
 412         }
 413
 414         /* Clean PShctx, since we never called _Final on it. */
 415         memset(&PShctx, 0, sizeof(HMAC_SHA256_CTX));
 416 }