1 /*
2  * Copyright (c) 2017 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 #define BR_ENABLE_INTRINSICS   1
26 #include "inner.h"
27 
28 /*
29  * This code contains the AES key schedule implementation using the
30  * AES-NI opcodes.
31  */
32 
33 #if BR_AES_X86NI
34 
35 /* see inner.h */
36 int
37 br_aes_x86ni_supported(void)
38 {
39 	/*
40 	 * Bit mask for features in ECX:
41 	 *   19   SSE4.1 (used for _mm_insert_epi32(), for AES-CTR)
42 	 *   25   AES-NI
43 	 */
44 	return br_cpuid(0, 0, 0x02080000, 0);
45 }
46 
47 BR_TARGETS_X86_UP
48 
49 BR_TARGET("sse2,aes")
50 static inline __m128i
51 expand_step128(__m128i k, __m128i k2)
52 {
53 	k = _mm_xor_si128(k, _mm_slli_si128(k, 4));
54 	k = _mm_xor_si128(k, _mm_slli_si128(k, 4));
55 	k = _mm_xor_si128(k, _mm_slli_si128(k, 4));
56 	k2 = _mm_shuffle_epi32(k2, 0xFF);
57 	return _mm_xor_si128(k, k2);
58 }
59 
60 BR_TARGET("sse2,aes")
61 static inline void
62 expand_step192(__m128i *t1, __m128i *t2, __m128i *t3)
63 {
64 	__m128i t4;
65 
66 	*t2 = _mm_shuffle_epi32(*t2, 0x55);
67 	t4 = _mm_slli_si128(*t1, 0x4);
68 	*t1 = _mm_xor_si128(*t1, t4);
69 	t4 = _mm_slli_si128(t4, 0x4);
70 	*t1 = _mm_xor_si128(*t1, t4);
71 	t4 = _mm_slli_si128(t4, 0x4);
72 	*t1 = _mm_xor_si128(*t1, t4);
73 	*t1 = _mm_xor_si128(*t1, *t2);
74 	*t2 = _mm_shuffle_epi32(*t1, 0xFF);
75 	t4 = _mm_slli_si128(*t3, 0x4);
76 	*t3 = _mm_xor_si128(*t3, t4);
77 	*t3 = _mm_xor_si128(*t3, *t2);
78 }
79 
80 BR_TARGET("sse2,aes")
81 static inline void
82 expand_step256_1(__m128i *t1, __m128i *t2)
83 {
84 	__m128i t4;
85 
86 	*t2 = _mm_shuffle_epi32(*t2, 0xFF);
87 	t4 = _mm_slli_si128(*t1, 0x4);
88 	*t1 = _mm_xor_si128(*t1, t4);
89 	t4 = _mm_slli_si128(t4, 0x4);
90 	*t1 = _mm_xor_si128(*t1, t4);
91 	t4 = _mm_slli_si128(t4, 0x4);
92 	*t1 = _mm_xor_si128(*t1, t4);
93 	*t1 = _mm_xor_si128(*t1, *t2);
94 }
95 
96 BR_TARGET("sse2,aes")
97 static inline void
98 expand_step256_2(__m128i *t1, __m128i *t3)
99 {
100 	__m128i t2, t4;
101 
102 	t4 = _mm_aeskeygenassist_si128(*t1, 0x0);
103 	t2 = _mm_shuffle_epi32(t4, 0xAA);
104 	t4 = _mm_slli_si128(*t3, 0x4);
105 	*t3 = _mm_xor_si128(*t3, t4);
106 	t4 = _mm_slli_si128(t4, 0x4);
107 	*t3 = _mm_xor_si128(*t3, t4);
108 	t4 = _mm_slli_si128(t4, 0x4);
109 	*t3 = _mm_xor_si128(*t3, t4);
110 	*t3 = _mm_xor_si128(*t3, t2);
111 }
112 
113 /*
114  * Perform key schedule for AES, encryption direction. Subkeys are written
115  * in sk[], and the number of rounds is returned. Key length MUST be 16,
116  * 24 or 32 bytes.
117  */
118 BR_TARGET("sse2,aes")
119 static unsigned
120 x86ni_keysched(__m128i *sk, const void *key, size_t len)
121 {
122 	const unsigned char *kb;
123 
124 #define KEXP128(k, i, rcon)   do { \
125 		k = expand_step128(k, _mm_aeskeygenassist_si128(k, rcon)); \
126 		sk[i] = k; \
127 	} while (0)
128 
129 #define KEXP192(i, rcon1, rcon2)   do { \
130 		sk[(i) + 0] = t1; \
131 		sk[(i) + 1] = t3; \
132 		t2 = _mm_aeskeygenassist_si128(t3, rcon1); \
133 		expand_step192(&t1, &t2, &t3); \
134 		sk[(i) + 1] = _mm_castpd_si128(_mm_shuffle_pd( \
135 			_mm_castsi128_pd(sk[(i) + 1]), \
136 			_mm_castsi128_pd(t1), 0)); \
137 		sk[(i) + 2] = _mm_castpd_si128(_mm_shuffle_pd( \
138 			_mm_castsi128_pd(t1), \
139 			_mm_castsi128_pd(t3), 1)); \
140 		t2 = _mm_aeskeygenassist_si128(t3, rcon2); \
141 		expand_step192(&t1, &t2, &t3); \
142 	} while (0)
143 
144 #define KEXP256(i, rcon)   do { \
145 		sk[(i) + 0] = t3; \
146 		t2 = _mm_aeskeygenassist_si128(t3, rcon); \
147 		expand_step256_1(&t1, &t2); \
148 		sk[(i) + 1] = t1; \
149 		expand_step256_2(&t1, &t3); \
150 	} while (0)
151 
152 	kb = key;
153 	switch (len) {
154 		__m128i t1, t2, t3;
155 
156 	case 16:
157 		t1 = _mm_loadu_si128((const void *)kb);
158 		sk[0] = t1;
159 		KEXP128(t1,  1, 0x01);
160 		KEXP128(t1,  2, 0x02);
161 		KEXP128(t1,  3, 0x04);
162 		KEXP128(t1,  4, 0x08);
163 		KEXP128(t1,  5, 0x10);
164 		KEXP128(t1,  6, 0x20);
165 		KEXP128(t1,  7, 0x40);
166 		KEXP128(t1,  8, 0x80);
167 		KEXP128(t1,  9, 0x1B);
168 		KEXP128(t1, 10, 0x36);
169 		return 10;
170 
171 	case 24:
172 		t1 = _mm_loadu_si128((const void *)kb);
173 		t3 = _mm_loadu_si128((const void *)(kb + 8));
174 		t3 = _mm_shuffle_epi32(t3, 0x4E);
175 		KEXP192(0, 0x01, 0x02);
176 		KEXP192(3, 0x04, 0x08);
177 		KEXP192(6, 0x10, 0x20);
178 		KEXP192(9, 0x40, 0x80);
179 		sk[12] = t1;
180 		return 12;
181 
182 	case 32:
183 		t1 = _mm_loadu_si128((const void *)kb);
184 		t3 = _mm_loadu_si128((const void *)(kb + 16));
185 		sk[0] = t1;
186 		KEXP256( 1, 0x01);
187 		KEXP256( 3, 0x02);
188 		KEXP256( 5, 0x04);
189 		KEXP256( 7, 0x08);
190 		KEXP256( 9, 0x10);
191 		KEXP256(11, 0x20);
192 		sk[13] = t3;
193 		t2 = _mm_aeskeygenassist_si128(t3, 0x40);
194 		expand_step256_1(&t1, &t2);
195 		sk[14] = t1;
196 		return 14;
197 
198 	default:
199 		return 0;
200 	}
201 
202 #undef KEXP128
203 #undef KEXP192
204 #undef KEXP256
205 }
206 
207 /* see inner.h */
208 BR_TARGET("sse2,aes")
209 unsigned
210 br_aes_x86ni_keysched_enc(unsigned char *skni, const void *key, size_t len)
211 {
212 	__m128i sk[15];
213 	unsigned num_rounds;
214 
215 	num_rounds = x86ni_keysched(sk, key, len);
216 	memcpy(skni, sk, (num_rounds + 1) << 4);
217 	return num_rounds;
218 }
219 
220 /* see inner.h */
221 BR_TARGET("sse2,aes")
222 unsigned
223 br_aes_x86ni_keysched_dec(unsigned char *skni, const void *key, size_t len)
224 {
225 	__m128i sk[15];
226 	unsigned u, num_rounds;
227 
228 	num_rounds = x86ni_keysched(sk, key, len);
229 	_mm_storeu_si128((void *)skni, sk[num_rounds]);
230 	for (u = 1; u < num_rounds; u ++) {
231 		_mm_storeu_si128((void *)(skni + (u << 4)),
232 			_mm_aesimc_si128(sk[num_rounds - u]));
233 	}
234 	_mm_storeu_si128((void *)(skni + (num_rounds << 4)), sk[0]);
235 	return num_rounds;
236 }
237 
238 BR_TARGETS_X86_DOWN
239 
240 #endif
241