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 __FBSDID("$FreeBSD$"); 46 47 #include <sys/param.h> 48 #include <sys/types.h> 49 #include <sys/systm.h> 50 #include <sys/libkern.h> 51 #include <sys/endian.h> 52 53 #include <crypto/siphash/siphash.h> 54 55 static void SipRounds(SIPHASH_CTX *ctx, int final); 56 57 void 58 SipHash_InitX(SIPHASH_CTX *ctx, int rc, int rf) 59 { 60 61 ctx->v[0] = 0x736f6d6570736575ull; 62 ctx->v[1] = 0x646f72616e646f6dull; 63 ctx->v[2] = 0x6c7967656e657261ull; 64 ctx->v[3] = 0x7465646279746573ull; 65 ctx->buf.b64 = 0; 66 ctx->bytes = 0; 67 ctx->buflen = 0; 68 ctx->rounds_compr = rc; 69 ctx->rounds_final = rf; 70 ctx->initialized = 1; 71 } 72 73 void 74 SipHash_SetKey(SIPHASH_CTX *ctx, const uint8_t key[static SIPHASH_KEY_LENGTH]) 75 { 76 uint64_t k[2]; 77 78 KASSERT(ctx->v[0] == 0x736f6d6570736575ull && 79 ctx->initialized == 1, 80 ("%s: context %p not properly initialized", __func__, ctx)); 81 82 k[0] = le64dec(&key[0]); 83 k[1] = le64dec(&key[8]); 84 85 ctx->v[0] ^= k[0]; 86 ctx->v[1] ^= k[1]; 87 ctx->v[2] ^= k[0]; 88 ctx->v[3] ^= k[1]; 89 90 ctx->initialized = 2; 91 } 92 93 static size_t 94 SipBuf(SIPHASH_CTX *ctx, const uint8_t **src, size_t len, int final) 95 { 96 size_t x = 0; 97 98 KASSERT((!final && len > 0) || (final && len == 0), 99 ("%s: invalid parameters", __func__)); 100 101 if (!final) { 102 x = MIN(len, sizeof(ctx->buf.b64) - ctx->buflen); 103 bcopy(*src, &ctx->buf.b8[ctx->buflen], x); 104 ctx->buflen += x; 105 *src += x; 106 } else 107 ctx->buf.b8[7] = (uint8_t)ctx->bytes; 108 109 if (ctx->buflen == 8 || final) { 110 ctx->v[3] ^= le64toh(ctx->buf.b64); 111 SipRounds(ctx, 0); 112 ctx->v[0] ^= le64toh(ctx->buf.b64); 113 ctx->buf.b64 = 0; 114 ctx->buflen = 0; 115 } 116 return (x); 117 } 118 119 void 120 SipHash_Update(SIPHASH_CTX *ctx, const void *src, size_t len) 121 { 122 uint64_t m; 123 const uint64_t *p; 124 const uint8_t *s; 125 size_t rem; 126 127 KASSERT(ctx->initialized == 2, 128 ("%s: context %p not properly initialized", __func__, ctx)); 129 130 s = src; 131 ctx->bytes += len; 132 133 /* 134 * Push length smaller than block size into buffer or 135 * fill up the buffer if there is already something 136 * in it. 137 */ 138 if (ctx->buflen > 0 || len < 8) 139 len -= SipBuf(ctx, &s, len, 0); 140 if (len == 0) 141 return; 142 143 rem = len & 0x7; 144 len >>= 3; 145 146 /* Optimze for 64bit aligned/unaligned access. */ 147 if (((uintptr_t)s & 0x7) == 0) { 148 for (p = (const uint64_t *)s; len > 0; len--, p++) { 149 m = le64toh(*p); 150 ctx->v[3] ^= m; 151 SipRounds(ctx, 0); 152 ctx->v[0] ^= m; 153 } 154 s = (const uint8_t *)p; 155 } else { 156 for (; len > 0; len--, s += 8) { 157 m = le64dec(s); 158 ctx->v[3] ^= m; 159 SipRounds(ctx, 0); 160 ctx->v[0] ^= m; 161 } 162 } 163 164 /* Push remainder into buffer. */ 165 if (rem > 0) 166 (void)SipBuf(ctx, &s, rem, 0); 167 } 168 169 void 170 SipHash_Final(uint8_t dst[static SIPHASH_DIGEST_LENGTH], SIPHASH_CTX *ctx) 171 { 172 uint64_t r; 173 174 KASSERT(ctx->initialized == 2, 175 ("%s: context %p not properly initialized", __func__, ctx)); 176 177 r = SipHash_End(ctx); 178 le64enc(dst, r); 179 } 180 181 uint64_t 182 SipHash_End(SIPHASH_CTX *ctx) 183 { 184 uint64_t r; 185 186 KASSERT(ctx->initialized == 2, 187 ("%s: context %p not properly initialized", __func__, ctx)); 188 189 SipBuf(ctx, NULL, 0, 1); 190 ctx->v[2] ^= 0xff; 191 SipRounds(ctx, 1); 192 r = (ctx->v[0] ^ ctx->v[1]) ^ (ctx->v[2] ^ ctx->v[3]); 193 194 bzero(ctx, sizeof(*ctx)); 195 return (r); 196 } 197 198 uint64_t 199 SipHashX(SIPHASH_CTX *ctx, int rc, int rf, 200 const uint8_t key[static SIPHASH_KEY_LENGTH], const void *src, size_t len) 201 { 202 203 SipHash_InitX(ctx, rc, rf); 204 SipHash_SetKey(ctx, key); 205 SipHash_Update(ctx, src, len); 206 207 return (SipHash_End(ctx)); 208 } 209 210 #define SIP_ROTL(x, b) (uint64_t)(((x) << (b)) | ( (x) >> (64 - (b)))) 211 212 static void 213 SipRounds(SIPHASH_CTX *ctx, int final) 214 { 215 int rounds; 216 217 if (!final) 218 rounds = ctx->rounds_compr; 219 else 220 rounds = ctx->rounds_final; 221 222 while (rounds--) { 223 ctx->v[0] += ctx->v[1]; 224 ctx->v[2] += ctx->v[3]; 225 ctx->v[1] = SIP_ROTL(ctx->v[1], 13); 226 ctx->v[3] = SIP_ROTL(ctx->v[3], 16); 227 228 ctx->v[1] ^= ctx->v[0]; 229 ctx->v[3] ^= ctx->v[2]; 230 ctx->v[0] = SIP_ROTL(ctx->v[0], 32); 231 232 ctx->v[2] += ctx->v[1]; 233 ctx->v[0] += ctx->v[3]; 234 ctx->v[1] = SIP_ROTL(ctx->v[1], 17); 235 ctx->v[3] = SIP_ROTL(ctx->v[3], 21); 236 237 ctx->v[1] ^= ctx->v[2]; 238 ctx->v[3] ^= ctx->v[0]; 239 ctx->v[2] = SIP_ROTL(ctx->v[2], 32); 240 } 241 } 242 243