1 /*
2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #include "inner.h"
26
27 /* see bearssl_block.h */
28 void
br_aes_ct64_ctr_init(br_aes_ct64_ctr_keys * ctx,const void * key,size_t len)29 br_aes_ct64_ctr_init(br_aes_ct64_ctr_keys *ctx,
30 const void *key, size_t len)
31 {
32 ctx->vtable = &br_aes_ct64_ctr_vtable;
33 ctx->num_rounds = br_aes_ct64_keysched(ctx->skey, key, len);
34 }
35
36 static void
xorbuf(void * dst,const void * src,size_t len)37 xorbuf(void *dst, const void *src, size_t len)
38 {
39 unsigned char *d;
40 const unsigned char *s;
41
42 d = dst;
43 s = src;
44 while (len -- > 0) {
45 *d ++ ^= *s ++;
46 }
47 }
48
49 /* see bearssl_block.h */
50 uint32_t
br_aes_ct64_ctr_run(const br_aes_ct64_ctr_keys * ctx,const void * iv,uint32_t cc,void * data,size_t len)51 br_aes_ct64_ctr_run(const br_aes_ct64_ctr_keys *ctx,
52 const void *iv, uint32_t cc, void *data, size_t len)
53 {
54 unsigned char *buf;
55 uint32_t ivw[16];
56 uint64_t sk_exp[120];
57
58 br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
59 br_range_dec32le(ivw, 3, iv);
60 memcpy(ivw + 4, ivw, 3 * sizeof(uint32_t));
61 memcpy(ivw + 8, ivw, 3 * sizeof(uint32_t));
62 memcpy(ivw + 12, ivw, 3 * sizeof(uint32_t));
63 buf = data;
64 while (len > 0) {
65 uint64_t q[8];
66 uint32_t w[16];
67 unsigned char tmp[64];
68 int i;
69
70 /*
71 * TODO: see if we can save on the first br_aes_ct64_ortho()
72 * call, since iv0/iv1/iv2 are constant for the whole run.
73 */
74 memcpy(w, ivw, sizeof ivw);
75 w[3] = br_swap32(cc);
76 w[7] = br_swap32(cc + 1);
77 w[11] = br_swap32(cc + 2);
78 w[15] = br_swap32(cc + 3);
79 for (i = 0; i < 4; i ++) {
80 br_aes_ct64_interleave_in(
81 &q[i], &q[i + 4], w + (i << 2));
82 }
83 br_aes_ct64_ortho(q);
84 br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
85 br_aes_ct64_ortho(q);
86 for (i = 0; i < 4; i ++) {
87 br_aes_ct64_interleave_out(
88 w + (i << 2), q[i], q[i + 4]);
89 }
90 br_range_enc32le(tmp, w, 16);
91 if (len <= 64) {
92 xorbuf(buf, tmp, len);
93 cc += (uint32_t)len >> 4;
94 break;
95 }
96 xorbuf(buf, tmp, 64);
97 buf += 64;
98 len -= 64;
99 cc += 4;
100 }
101 return cc;
102 }
103
104 /* see bearssl_block.h */
105 const br_block_ctr_class br_aes_ct64_ctr_vtable = {
106 sizeof(br_aes_ct64_ctr_keys),
107 16,
108 4,
109 (void (*)(const br_block_ctr_class **, const void *, size_t))
110 &br_aes_ct64_ctr_init,
111 (uint32_t (*)(const br_block_ctr_class *const *,
112 const void *, uint32_t, void *, size_t))
113 &br_aes_ct64_ctr_run
114 };
115