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