File Coverage

src/symcipher/aes_ct_cbcdec.c

Criterion	Covered	Total	%
statement	0	55	0.0
branch	0	6	0.0
condition			n/a
subroutine			n/a
pod			n/a
total	0	61	0.0

line	stmt	bran	code
1			/*
2			* Copyright (c) 2016 Thomas Pornin
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
29	0		br_aes_ct_cbcdec_init(br_aes_ct_cbcdec_keys *ctx,
30			const void *key, size_t len)
31			{
32	0		ctx->vtable = &br_aes_ct_cbcdec_vtable;
33	0		ctx->num_rounds = br_aes_ct_keysched(ctx->skey, key, len);
34	0		}
35
36			/* see bearssl_block.h */
37			void
38	0		br_aes_ct_cbcdec_run(const br_aes_ct_cbcdec_keys *ctx,
39			void iv, void data, size_t len)
40			{
41			unsigned char buf, ivbuf;
42			uint32_t iv0, iv1, iv2, iv3;
43			uint32_t sk_exp[120];
44
45	0		br_aes_ct_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
46	0		ivbuf = iv;
47	0		iv0 = br_dec32le(ivbuf);
48	0		iv1 = br_dec32le(ivbuf + 4);
49	0		iv2 = br_dec32le(ivbuf + 8);
50	0		iv3 = br_dec32le(ivbuf + 12);
51	0		buf = data;
52	0	0	while (len > 0) {
53			uint32_t q[8], sq[8];
54
55	0		q[0] = br_dec32le(buf);
56	0		q[2] = br_dec32le(buf + 4);
57	0		q[4] = br_dec32le(buf + 8);
58	0		q[6] = br_dec32le(buf + 12);
59	0	0	if (len >= 32) {
60	0		q[1] = br_dec32le(buf + 16);
61	0		q[3] = br_dec32le(buf + 20);
62	0		q[5] = br_dec32le(buf + 24);
63	0		q[7] = br_dec32le(buf + 28);
64			} else {
65	0		q[1] = 0;
66	0		q[3] = 0;
67	0		q[5] = 0;
68	0		q[7] = 0;
69			}
70	0		memcpy(sq, q, sizeof q);
71	0		br_aes_ct_ortho(q);
72	0		br_aes_ct_bitslice_decrypt(ctx->num_rounds, sk_exp, q);
73	0		br_aes_ct_ortho(q);
74	0		br_enc32le(buf, q[0] ^ iv0);
75	0		br_enc32le(buf + 4, q[2] ^ iv1);
76	0		br_enc32le(buf + 8, q[4] ^ iv2);
77	0		br_enc32le(buf + 12, q[6] ^ iv3);
78	0	0	if (len < 32) {
79	0		iv0 = sq[0];
80	0		iv1 = sq[2];
81	0		iv2 = sq[4];
82	0		iv3 = sq[6];
83	0		break;
84			}
85	0		br_enc32le(buf + 16, q[1] ^ sq[0]);
86	0		br_enc32le(buf + 20, q[3] ^ sq[2]);
87	0		br_enc32le(buf + 24, q[5] ^ sq[4]);
88	0		br_enc32le(buf + 28, q[7] ^ sq[6]);
89	0		iv0 = sq[1];
90	0		iv1 = sq[3];
91	0		iv2 = sq[5];
92	0		iv3 = sq[7];
93	0		buf += 32;
94	0		len -= 32;
95			}
96	0		br_enc32le(ivbuf, iv0);
97	0		br_enc32le(ivbuf + 4, iv1);
98	0		br_enc32le(ivbuf + 8, iv2);
99	0		br_enc32le(ivbuf + 12, iv3);
100	0		}
101
102			/* see bearssl_block.h */
103			const br_block_cbcdec_class br_aes_ct_cbcdec_vtable = {
104			sizeof(br_aes_ct_cbcdec_keys),
105			16,
106			4,
107			(void ()(const br_block_cbcdec_class , const void , size_t))
108			&br_aes_ct_cbcdec_init,
109			(void ()(const br_block_cbcdec_class const , void , void *, size_t))
110			&br_aes_ct_cbcdec_run
111			};