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_ct_cbcenc_init(br_aes_ct_cbcenc_keys * ctx,const void * key,size_t len)29 br_aes_ct_cbcenc_init(br_aes_ct_cbcenc_keys *ctx,
30 	const void *key, size_t len)
31 {
32 	ctx->vtable = &br_aes_ct_cbcenc_vtable;
33 	ctx->num_rounds = br_aes_ct_keysched(ctx->skey, key, len);
34 }
35 
36 /* see bearssl_block.h */
37 void
br_aes_ct_cbcenc_run(const br_aes_ct_cbcenc_keys * ctx,void * iv,void * data,size_t len)38 br_aes_ct_cbcenc_run(const br_aes_ct_cbcenc_keys *ctx,
39 	void *iv, void *data, size_t len)
40 {
41 	unsigned char *buf, *ivbuf;
42 	uint32_t q[8];
43 	uint32_t iv0, iv1, iv2, iv3;
44 	uint32_t sk_exp[120];
45 
46 	q[1] = 0;
47 	q[3] = 0;
48 	q[5] = 0;
49 	q[7] = 0;
50 	br_aes_ct_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
51 	ivbuf = iv;
52 	iv0 = br_dec32le(ivbuf);
53 	iv1 = br_dec32le(ivbuf + 4);
54 	iv2 = br_dec32le(ivbuf + 8);
55 	iv3 = br_dec32le(ivbuf + 12);
56 	buf = data;
57 	while (len > 0) {
58 		q[0] = iv0 ^ br_dec32le(buf);
59 		q[2] = iv1 ^ br_dec32le(buf + 4);
60 		q[4] = iv2 ^ br_dec32le(buf + 8);
61 		q[6] = iv3 ^ br_dec32le(buf + 12);
62 		br_aes_ct_ortho(q);
63 		br_aes_ct_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
64 		br_aes_ct_ortho(q);
65 		iv0 = q[0];
66 		iv1 = q[2];
67 		iv2 = q[4];
68 		iv3 = q[6];
69 		br_enc32le(buf, iv0);
70 		br_enc32le(buf + 4, iv1);
71 		br_enc32le(buf + 8, iv2);
72 		br_enc32le(buf + 12, iv3);
73 		buf += 16;
74 		len -= 16;
75 	}
76 	br_enc32le(ivbuf, iv0);
77 	br_enc32le(ivbuf + 4, iv1);
78 	br_enc32le(ivbuf + 8, iv2);
79 	br_enc32le(ivbuf + 12, iv3);
80 }
81 
82 /* see bearssl_block.h */
83 const br_block_cbcenc_class br_aes_ct_cbcenc_vtable = {
84 	sizeof(br_aes_ct_cbcenc_keys),
85 	16,
86 	4,
87 	(void (*)(const br_block_cbcenc_class **, const void *, size_t))
88 		&br_aes_ct_cbcenc_init,
89 	(void (*)(const br_block_cbcenc_class *const *, void *, void *, size_t))
90 		&br_aes_ct_cbcenc_run
91 };
92