1 /*- 2 * Copyright (c) 2013 Andre Oppermann <andre@FreeBSD.org> 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 * 3. The name of the author may not be used to endorse or promote 14 * products derived from this software without specific prior written 15 * permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 /* 31 * SipHash is a family of PRFs SipHash-c-d where the integer parameters c and d 32 * are the number of compression rounds and the number of finalization rounds. 33 * A compression round is identical to a finalization round and this round 34 * function is called SipRound. Given a 128-bit key k and a (possibly empty) 35 * byte string m, SipHash-c-d returns a 64-bit value SipHash-c-d(k; m). 36 * 37 * Implemented from the paper "SipHash: a fast short-input PRF", 2012.09.18, 38 * by Jean-Philippe Aumasson and Daniel J. Bernstein, 39 * Permanent Document ID b9a943a805fbfc6fde808af9fc0ecdfa 40 * https://131002.net/siphash/siphash.pdf 41 * https://131002.net/siphash/ 42 */ 43 44 #include <sys/param.h> 45 #include <sys/types.h> 46 #include <sys/systm.h> 47 #include <sys/libkern.h> 48 #include <sys/endian.h> 49 50 #include <crypto/siphash/siphash.h> 51 52 static void SipRounds(SIPHASH_CTX *ctx, int final); 53 54 void 55 SipHash_InitX(SIPHASH_CTX *ctx, int rc, int rf) 56 { 57 58 ctx->v[0] = 0x736f6d6570736575ull; 59 ctx->v[1] = 0x646f72616e646f6dull; 60 ctx->v[2] = 0x6c7967656e657261ull; 61 ctx->v[3] = 0x7465646279746573ull; 62 ctx->buf.b64 = 0; 63 ctx->bytes = 0; 64 ctx->buflen = 0; 65 ctx->rounds_compr = rc; 66 ctx->rounds_final = rf; 67 ctx->initialized = 1; 68 } 69 70 void 71 SipHash_SetKey(SIPHASH_CTX *ctx, const uint8_t key[static SIPHASH_KEY_LENGTH]) 72 { 73 uint64_t k[2]; 74 75 KASSERT(ctx->v[0] == 0x736f6d6570736575ull && 76 ctx->initialized == 1, 77 ("%s: context %p not properly initialized", __func__, ctx)); 78 79 k[0] = le64dec(&key[0]); 80 k[1] = le64dec(&key[8]); 81 82 ctx->v[0] ^= k[0]; 83 ctx->v[1] ^= k[1]; 84 ctx->v[2] ^= k[0]; 85 ctx->v[3] ^= k[1]; 86 87 ctx->initialized = 2; 88 } 89 90 static size_t 91 SipBuf(SIPHASH_CTX *ctx, const uint8_t **src, size_t len, int final) 92 { 93 size_t x = 0; 94 95 /* handle hashing 0 length buffer - needed for test vectors */ 96 if (len == 0 && final == 0) 97 return (0); 98 99 if (final) { 100 KASSERT(len == 0, ("%s: invalid len param", __func__)); 101 ctx->buf.b8[7] = (uint8_t)ctx->bytes; 102 } else { 103 KASSERT((len > 0) && src && *src, 104 ("%s: invalid parameters", __func__)); 105 x = MIN(len, sizeof(ctx->buf.b64) - ctx->buflen); 106 bcopy(*src, &ctx->buf.b8[ctx->buflen], x); 107 ctx->buflen += x; 108 *src += x; 109 } 110 111 if (ctx->buflen == 8 || final) { 112 ctx->v[3] ^= le64toh(ctx->buf.b64); 113 SipRounds(ctx, 0); 114 ctx->v[0] ^= le64toh(ctx->buf.b64); 115 ctx->buf.b64 = 0; 116 ctx->buflen = 0; 117 } 118 return (x); 119 } 120 121 void 122 SipHash_Update(SIPHASH_CTX *ctx, const void *src, size_t len) 123 { 124 uint64_t m; 125 const uint64_t *p; 126 const uint8_t *s; 127 size_t rem; 128 129 KASSERT(ctx->initialized == 2, 130 ("%s: context %p not properly initialized", __func__, ctx)); 131 132 s = src; 133 ctx->bytes += len; 134 135 /* 136 * Push length smaller than block size into buffer or 137 * fill up the buffer if there is already something 138 * in it. 139 */ 140 if (ctx->buflen > 0 || len < 8) 141 len -= SipBuf(ctx, &s, len, 0); 142 if (len == 0) 143 return; 144 145 rem = len & 0x7; 146 len >>= 3; 147 148 /* Optimze for 64bit aligned/unaligned access. */ 149 if (((uintptr_t)s & 0x7) == 0) { 150 for (p = (const uint64_t *)s; len > 0; len--, p++) { 151 m = le64toh(*p); 152 ctx->v[3] ^= m; 153 SipRounds(ctx, 0); 154 ctx->v[0] ^= m; 155 } 156 s = (const uint8_t *)p; 157 } else { 158 for (; len > 0; len--, s += 8) { 159 m = le64dec(s); 160 ctx->v[3] ^= m; 161 SipRounds(ctx, 0); 162 ctx->v[0] ^= m; 163 } 164 } 165 166 /* Push remainder into buffer. */ 167 if (rem > 0) 168 (void)SipBuf(ctx, &s, rem, 0); 169 } 170 171 void 172 SipHash_Final(uint8_t dst[static SIPHASH_DIGEST_LENGTH], SIPHASH_CTX *ctx) 173 { 174 uint64_t r; 175 176 KASSERT(ctx->initialized == 2, 177 ("%s: context %p not properly initialized", __func__, ctx)); 178 179 r = SipHash_End(ctx); 180 le64enc(dst, r); 181 } 182 183 uint64_t 184 SipHash_End(SIPHASH_CTX *ctx) 185 { 186 uint64_t r; 187 188 KASSERT(ctx->initialized == 2, 189 ("%s: context %p not properly initialized", __func__, ctx)); 190 191 SipBuf(ctx, NULL, 0, 1); 192 ctx->v[2] ^= 0xff; 193 SipRounds(ctx, 1); 194 r = (ctx->v[0] ^ ctx->v[1]) ^ (ctx->v[2] ^ ctx->v[3]); 195 196 bzero(ctx, sizeof(*ctx)); 197 return (r); 198 } 199 200 uint64_t 201 SipHashX(SIPHASH_CTX *ctx, int rc, int rf, 202 const uint8_t key[static SIPHASH_KEY_LENGTH], const void *src, size_t len) 203 { 204 205 SipHash_InitX(ctx, rc, rf); 206 SipHash_SetKey(ctx, key); 207 SipHash_Update(ctx, src, len); 208 209 return (SipHash_End(ctx)); 210 } 211 212 #define SIP_ROTL(x, b) (uint64_t)(((x) << (b)) | ( (x) >> (64 - (b)))) 213 214 static void 215 SipRounds(SIPHASH_CTX *ctx, int final) 216 { 217 int rounds; 218 219 if (!final) 220 rounds = ctx->rounds_compr; 221 else 222 rounds = ctx->rounds_final; 223 224 while (rounds--) { 225 ctx->v[0] += ctx->v[1]; 226 ctx->v[2] += ctx->v[3]; 227 ctx->v[1] = SIP_ROTL(ctx->v[1], 13); 228 ctx->v[3] = SIP_ROTL(ctx->v[3], 16); 229 230 ctx->v[1] ^= ctx->v[0]; 231 ctx->v[3] ^= ctx->v[2]; 232 ctx->v[0] = SIP_ROTL(ctx->v[0], 32); 233 234 ctx->v[2] += ctx->v[1]; 235 ctx->v[0] += ctx->v[3]; 236 ctx->v[1] = SIP_ROTL(ctx->v[1], 17); 237 ctx->v[3] = SIP_ROTL(ctx->v[3], 21); 238 239 ctx->v[1] ^= ctx->v[2]; 240 ctx->v[3] ^= ctx->v[0]; 241 ctx->v[2] = SIP_ROTL(ctx->v[2], 32); 242 } 243 } 244 245