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/cdefs.h> 45 #include <sys/param.h> 46 #include <sys/types.h> 47 #include <sys/systm.h> 48 #include <sys/libkern.h> 49 #include <sys/endian.h> 50 51 #include <crypto/siphash/siphash.h> 52 53 static void SipRounds(SIPHASH_CTX *ctx, int final); 54 55 void 56 SipHash_InitX(SIPHASH_CTX *ctx, int rc, int rf) 57 { 58 59 ctx->v[0] = 0x736f6d6570736575ull; 60 ctx->v[1] = 0x646f72616e646f6dull; 61 ctx->v[2] = 0x6c7967656e657261ull; 62 ctx->v[3] = 0x7465646279746573ull; 63 ctx->buf.b64 = 0; 64 ctx->bytes = 0; 65 ctx->buflen = 0; 66 ctx->rounds_compr = rc; 67 ctx->rounds_final = rf; 68 ctx->initialized = 1; 69 } 70 71 void 72 SipHash_SetKey(SIPHASH_CTX *ctx, const uint8_t key[static SIPHASH_KEY_LENGTH]) 73 { 74 uint64_t k[2]; 75 76 KASSERT(ctx->v[0] == 0x736f6d6570736575ull && 77 ctx->initialized == 1, 78 ("%s: context %p not properly initialized", __func__, ctx)); 79 80 k[0] = le64dec(&key[0]); 81 k[1] = le64dec(&key[8]); 82 83 ctx->v[0] ^= k[0]; 84 ctx->v[1] ^= k[1]; 85 ctx->v[2] ^= k[0]; 86 ctx->v[3] ^= k[1]; 87 88 ctx->initialized = 2; 89 } 90 91 static size_t 92 SipBuf(SIPHASH_CTX *ctx, const uint8_t **src, size_t len, int final) 93 { 94 size_t x = 0; 95 96 KASSERT((!final && len > 0) || (final && len == 0), 97 ("%s: invalid parameters", __func__)); 98 99 if (!final) { 100 x = MIN(len, sizeof(ctx->buf.b64) - ctx->buflen); 101 bcopy(*src, &ctx->buf.b8[ctx->buflen], x); 102 ctx->buflen += x; 103 *src += x; 104 } else 105 ctx->buf.b8[7] = (uint8_t)ctx->bytes; 106 107 if (ctx->buflen == 8 || final) { 108 ctx->v[3] ^= le64toh(ctx->buf.b64); 109 SipRounds(ctx, 0); 110 ctx->v[0] ^= le64toh(ctx->buf.b64); 111 ctx->buf.b64 = 0; 112 ctx->buflen = 0; 113 } 114 return (x); 115 } 116 117 void 118 SipHash_Update(SIPHASH_CTX *ctx, const void *src, size_t len) 119 { 120 uint64_t m; 121 const uint64_t *p; 122 const uint8_t *s; 123 size_t rem; 124 125 KASSERT(ctx->initialized == 2, 126 ("%s: context %p not properly initialized", __func__, ctx)); 127 128 s = src; 129 ctx->bytes += len; 130 131 /* 132 * Push length smaller than block size into buffer or 133 * fill up the buffer if there is already something 134 * in it. 135 */ 136 if (ctx->buflen > 0 || len < 8) 137 len -= SipBuf(ctx, &s, len, 0); 138 if (len == 0) 139 return; 140 141 rem = len & 0x7; 142 len >>= 3; 143 144 /* Optimze for 64bit aligned/unaligned access. */ 145 if (((uintptr_t)s & 0x7) == 0) { 146 for (p = (const uint64_t *)s; len > 0; len--, p++) { 147 m = le64toh(*p); 148 ctx->v[3] ^= m; 149 SipRounds(ctx, 0); 150 ctx->v[0] ^= m; 151 } 152 s = (const uint8_t *)p; 153 } else { 154 for (; len > 0; len--, s += 8) { 155 m = le64dec(s); 156 ctx->v[3] ^= m; 157 SipRounds(ctx, 0); 158 ctx->v[0] ^= m; 159 } 160 } 161 162 /* Push remainder into buffer. */ 163 if (rem > 0) 164 (void)SipBuf(ctx, &s, rem, 0); 165 } 166 167 void 168 SipHash_Final(uint8_t dst[static SIPHASH_DIGEST_LENGTH], SIPHASH_CTX *ctx) 169 { 170 uint64_t r; 171 172 KASSERT(ctx->initialized == 2, 173 ("%s: context %p not properly initialized", __func__, ctx)); 174 175 r = SipHash_End(ctx); 176 le64enc(dst, r); 177 } 178 179 uint64_t 180 SipHash_End(SIPHASH_CTX *ctx) 181 { 182 uint64_t r; 183 184 KASSERT(ctx->initialized == 2, 185 ("%s: context %p not properly initialized", __func__, ctx)); 186 187 SipBuf(ctx, NULL, 0, 1); 188 ctx->v[2] ^= 0xff; 189 SipRounds(ctx, 1); 190 r = (ctx->v[0] ^ ctx->v[1]) ^ (ctx->v[2] ^ ctx->v[3]); 191 192 bzero(ctx, sizeof(*ctx)); 193 return (r); 194 } 195 196 uint64_t 197 SipHashX(SIPHASH_CTX *ctx, int rc, int rf, 198 const uint8_t key[static SIPHASH_KEY_LENGTH], const void *src, size_t len) 199 { 200 201 SipHash_InitX(ctx, rc, rf); 202 SipHash_SetKey(ctx, key); 203 SipHash_Update(ctx, src, len); 204 205 return (SipHash_End(ctx)); 206 } 207 208 #define SIP_ROTL(x, b) (uint64_t)(((x) << (b)) | ( (x) >> (64 - (b)))) 209 210 static void 211 SipRounds(SIPHASH_CTX *ctx, int final) 212 { 213 int rounds; 214 215 if (!final) 216 rounds = ctx->rounds_compr; 217 else 218 rounds = ctx->rounds_final; 219 220 while (rounds--) { 221 ctx->v[0] += ctx->v[1]; 222 ctx->v[2] += ctx->v[3]; 223 ctx->v[1] = SIP_ROTL(ctx->v[1], 13); 224 ctx->v[3] = SIP_ROTL(ctx->v[3], 16); 225 226 ctx->v[1] ^= ctx->v[0]; 227 ctx->v[3] ^= ctx->v[2]; 228 ctx->v[0] = SIP_ROTL(ctx->v[0], 32); 229 230 ctx->v[2] += ctx->v[1]; 231 ctx->v[0] += ctx->v[3]; 232 ctx->v[1] = SIP_ROTL(ctx->v[1], 17); 233 ctx->v[3] = SIP_ROTL(ctx->v[3], 21); 234 235 ctx->v[1] ^= ctx->v[2]; 236 ctx->v[3] ^= ctx->v[0]; 237 ctx->v[2] = SIP_ROTL(ctx->v[2], 32); 238 } 239 } 240 241