1 /*-
2 * Copyright (c) 2013 Andre Oppermann <[email protected]>
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
SipHash_InitX(SIPHASH_CTX * ctx,int rc,int rf)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
SipHash_SetKey(SIPHASH_CTX * ctx,const uint8_t key[static SIPHASH_KEY_LENGTH])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
SipBuf(SIPHASH_CTX * ctx,const uint8_t ** src,size_t len,int final)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
SipHash_Update(SIPHASH_CTX * ctx,const void * src,size_t len)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
SipHash_Final(uint8_t dst[static SIPHASH_DIGEST_LENGTH],SIPHASH_CTX * ctx)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
SipHash_End(SIPHASH_CTX * ctx)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
SipHashX(SIPHASH_CTX * ctx,int rc,int rf,const uint8_t key[static SIPHASH_KEY_LENGTH],const void * src,size_t len)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
SipRounds(SIPHASH_CTX * ctx,int final)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