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1 /* Copyright (c) 2014, Google Inc.
2  *
3  * Permission to use, copy, modify, and/or distribute this software for any
4  * purpose with or without fee is hereby granted, provided that the above
5  * copyright notice and this permission notice appear in all copies.
6  *
7  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14 
15 // This implementation was taken from the public domain, neon2 version in
16 // SUPERCOP by D. J. Bernstein and Peter Schwabe.
17 
18 #include <openssl/poly1305.h>
19 
20 #include <string.h>
21 
22 #include "../internal.h"
23 #include "internal.h"
24 
25 
26 #if defined(OPENSSL_POLY1305_NEON)
27 
28 typedef struct {
29   uint32_t v[12];  // for alignment; only using 10
30 } fe1305x2;
31 
32 #define addmulmod openssl_poly1305_neon2_addmulmod
33 #define blocks openssl_poly1305_neon2_blocks
34 
35 extern void addmulmod(fe1305x2 *r, const fe1305x2 *x, const fe1305x2 *y,
36                       const fe1305x2 *c);
37 
38 extern int blocks(fe1305x2 *h, const fe1305x2 *precomp, const uint8_t *in,
39                   unsigned int inlen);
40 
freeze(fe1305x2 * r)41 static void freeze(fe1305x2 *r) {
42   int i;
43 
44   uint32_t x0 = r->v[0];
45   uint32_t x1 = r->v[2];
46   uint32_t x2 = r->v[4];
47   uint32_t x3 = r->v[6];
48   uint32_t x4 = r->v[8];
49   uint32_t y0;
50   uint32_t y1;
51   uint32_t y2;
52   uint32_t y3;
53   uint32_t y4;
54   uint32_t swap;
55 
56   for (i = 0; i < 3; ++i) {
57     x1 += x0 >> 26;
58     x0 &= 0x3ffffff;
59     x2 += x1 >> 26;
60     x1 &= 0x3ffffff;
61     x3 += x2 >> 26;
62     x2 &= 0x3ffffff;
63     x4 += x3 >> 26;
64     x3 &= 0x3ffffff;
65     x0 += 5 * (x4 >> 26);
66     x4 &= 0x3ffffff;
67   }
68 
69   y0 = x0 + 5;
70   y1 = x1 + (y0 >> 26);
71   y0 &= 0x3ffffff;
72   y2 = x2 + (y1 >> 26);
73   y1 &= 0x3ffffff;
74   y3 = x3 + (y2 >> 26);
75   y2 &= 0x3ffffff;
76   y4 = x4 + (y3 >> 26);
77   y3 &= 0x3ffffff;
78   swap = -(y4 >> 26);
79   y4 &= 0x3ffffff;
80 
81   y0 ^= x0;
82   y1 ^= x1;
83   y2 ^= x2;
84   y3 ^= x3;
85   y4 ^= x4;
86 
87   y0 &= swap;
88   y1 &= swap;
89   y2 &= swap;
90   y3 &= swap;
91   y4 &= swap;
92 
93   y0 ^= x0;
94   y1 ^= x1;
95   y2 ^= x2;
96   y3 ^= x3;
97   y4 ^= x4;
98 
99   r->v[0] = y0;
100   r->v[2] = y1;
101   r->v[4] = y2;
102   r->v[6] = y3;
103   r->v[8] = y4;
104 }
105 
fe1305x2_tobytearray(uint8_t * r,fe1305x2 * x)106 static void fe1305x2_tobytearray(uint8_t *r, fe1305x2 *x) {
107   uint32_t x0 = x->v[0];
108   uint32_t x1 = x->v[2];
109   uint32_t x2 = x->v[4];
110   uint32_t x3 = x->v[6];
111   uint32_t x4 = x->v[8];
112 
113   x1 += x0 >> 26;
114   x0 &= 0x3ffffff;
115   x2 += x1 >> 26;
116   x1 &= 0x3ffffff;
117   x3 += x2 >> 26;
118   x2 &= 0x3ffffff;
119   x4 += x3 >> 26;
120   x3 &= 0x3ffffff;
121 
122   *(uint32_t *)r = x0 + (x1 << 26);
123   *(uint32_t *)(r + 4) = (x1 >> 6) + (x2 << 20);
124   *(uint32_t *)(r + 8) = (x2 >> 12) + (x3 << 14);
125   *(uint32_t *)(r + 12) = (x3 >> 18) + (x4 << 8);
126 }
127 
128 // load32 exists to avoid breaking strict aliasing rules in
129 // fe1305x2_frombytearray.
load32(uint8_t * t)130 static uint32_t load32(uint8_t *t) {
131   uint32_t tmp;
132   OPENSSL_memcpy(&tmp, t, sizeof(tmp));
133   return tmp;
134 }
135 
fe1305x2_frombytearray(fe1305x2 * r,const uint8_t * x,unsigned long long xlen)136 static void fe1305x2_frombytearray(fe1305x2 *r, const uint8_t *x,
137                                    unsigned long long xlen) {
138   unsigned i;
139   uint8_t t[17];
140 
141   for (i = 0; (i < 16) && (i < xlen); i++) {
142     t[i] = x[i];
143   }
144   xlen -= i;
145   x += i;
146   t[i++] = 1;
147   for (; i < 17; i++) {
148     t[i] = 0;
149   }
150 
151   r->v[0] = 0x3ffffff & load32(t);
152   r->v[2] = 0x3ffffff & (load32(t + 3) >> 2);
153   r->v[4] = 0x3ffffff & (load32(t + 6) >> 4);
154   r->v[6] = 0x3ffffff & (load32(t + 9) >> 6);
155   r->v[8] = load32(t + 13);
156 
157   if (xlen) {
158     for (i = 0; (i < 16) && (i < xlen); i++) {
159       t[i] = x[i];
160     }
161     t[i++] = 1;
162     for (; i < 17; i++) {
163       t[i] = 0;
164     }
165 
166     r->v[1] = 0x3ffffff & load32(t);
167     r->v[3] = 0x3ffffff & (load32(t + 3) >> 2);
168     r->v[5] = 0x3ffffff & (load32(t + 6) >> 4);
169     r->v[7] = 0x3ffffff & (load32(t + 9) >> 6);
170     r->v[9] = load32(t + 13);
171   } else {
172     r->v[1] = r->v[3] = r->v[5] = r->v[7] = r->v[9] = 0;
173   }
174 }
175 
176 static const alignas(16) fe1305x2 zero;
177 
178 struct poly1305_state_st {
179   uint8_t data[sizeof(fe1305x2[5]) + 128];
180   uint8_t buf[32];
181   unsigned int buf_used;
182   uint8_t key[16];
183 };
184 
CRYPTO_poly1305_init_neon(poly1305_state * state,const uint8_t key[32])185 void CRYPTO_poly1305_init_neon(poly1305_state *state, const uint8_t key[32]) {
186   struct poly1305_state_st *st = (struct poly1305_state_st *)(state);
187   fe1305x2 *const r = (fe1305x2 *)(st->data + (15 & (-(int)st->data)));
188   fe1305x2 *const h = r + 1;
189   fe1305x2 *const c = h + 1;
190   fe1305x2 *const precomp = c + 1;
191   unsigned int j;
192 
193   r->v[1] = r->v[0] = 0x3ffffff & *(uint32_t *)key;
194   r->v[3] = r->v[2] = 0x3ffff03 & ((*(uint32_t *)(key + 3)) >> 2);
195   r->v[5] = r->v[4] = 0x3ffc0ff & ((*(uint32_t *)(key + 6)) >> 4);
196   r->v[7] = r->v[6] = 0x3f03fff & ((*(uint32_t *)(key + 9)) >> 6);
197   r->v[9] = r->v[8] = 0x00fffff & ((*(uint32_t *)(key + 12)) >> 8);
198 
199   for (j = 0; j < 10; j++) {
200     h->v[j] = 0;  // XXX: should fast-forward a bit
201   }
202 
203   addmulmod(precomp, r, r, &zero);                  // precompute r^2
204   addmulmod(precomp + 1, precomp, precomp, &zero);  // precompute r^4
205 
206   OPENSSL_memcpy(st->key, key + 16, 16);
207   st->buf_used = 0;
208 }
209 
CRYPTO_poly1305_update_neon(poly1305_state * state,const uint8_t * in,size_t in_len)210 void CRYPTO_poly1305_update_neon(poly1305_state *state, const uint8_t *in,
211                                  size_t in_len) {
212   struct poly1305_state_st *st = (struct poly1305_state_st *)(state);
213   fe1305x2 *const r = (fe1305x2 *)(st->data + (15 & (-(int)st->data)));
214   fe1305x2 *const h = r + 1;
215   fe1305x2 *const c = h + 1;
216   fe1305x2 *const precomp = c + 1;
217   unsigned int i;
218 
219   if (st->buf_used) {
220     unsigned int todo = 32 - st->buf_used;
221     if (todo > in_len) {
222       todo = in_len;
223     }
224     for (i = 0; i < todo; i++) {
225       st->buf[st->buf_used + i] = in[i];
226     }
227     st->buf_used += todo;
228     in_len -= todo;
229     in += todo;
230 
231     if (st->buf_used == sizeof(st->buf) && in_len) {
232       addmulmod(h, h, precomp, &zero);
233       fe1305x2_frombytearray(c, st->buf, sizeof(st->buf));
234       for (i = 0; i < 10; i++) {
235         h->v[i] += c->v[i];
236       }
237       st->buf_used = 0;
238     }
239   }
240 
241   while (in_len > 32) {
242     unsigned int tlen = 1048576;
243     if (in_len < tlen) {
244       tlen = in_len;
245     }
246     tlen -= blocks(h, precomp, in, tlen);
247     in_len -= tlen;
248     in += tlen;
249   }
250 
251   if (in_len) {
252     for (i = 0; i < in_len; i++) {
253       st->buf[i] = in[i];
254     }
255     st->buf_used = in_len;
256   }
257 }
258 
CRYPTO_poly1305_finish_neon(poly1305_state * state,uint8_t mac[16])259 void CRYPTO_poly1305_finish_neon(poly1305_state *state, uint8_t mac[16]) {
260   struct poly1305_state_st *st = (struct poly1305_state_st *)(state);
261   fe1305x2 *const r = (fe1305x2 *)(st->data + (15 & (-(int)st->data)));
262   fe1305x2 *const h = r + 1;
263   fe1305x2 *const c = h + 1;
264   fe1305x2 *const precomp = c + 1;
265 
266   addmulmod(h, h, precomp, &zero);
267 
268   if (st->buf_used > 16) {
269     fe1305x2_frombytearray(c, st->buf, st->buf_used);
270     precomp->v[1] = r->v[1];
271     precomp->v[3] = r->v[3];
272     precomp->v[5] = r->v[5];
273     precomp->v[7] = r->v[7];
274     precomp->v[9] = r->v[9];
275     addmulmod(h, h, precomp, c);
276   } else if (st->buf_used > 0) {
277     fe1305x2_frombytearray(c, st->buf, st->buf_used);
278     r->v[1] = 1;
279     r->v[3] = 0;
280     r->v[5] = 0;
281     r->v[7] = 0;
282     r->v[9] = 0;
283     addmulmod(h, h, r, c);
284   }
285 
286   h->v[0] += h->v[1];
287   h->v[2] += h->v[3];
288   h->v[4] += h->v[5];
289   h->v[6] += h->v[7];
290   h->v[8] += h->v[9];
291   freeze(h);
292 
293   fe1305x2_frombytearray(c, st->key, 16);
294   c->v[8] ^= (1 << 24);
295 
296   h->v[0] += c->v[0];
297   h->v[2] += c->v[2];
298   h->v[4] += c->v[4];
299   h->v[6] += c->v[6];
300   h->v[8] += c->v[8];
301   fe1305x2_tobytearray(mac, h);
302 }
303 
304 #endif  // OPENSSL_POLY1305_NEON
305