aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/src/crypto/chacha20.c
blob: c23928e79879141fd80a3ce4d954f8c25ff2030c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
/* SPDX-License-Identifier: GPL-2.0
 *
 * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 */

#include "chacha20.h"

#include <asm/unaligned.h>
#include <linux/kernel.h>
#include <crypto/algapi.h>

#if defined(CONFIG_X86_64)
#include <asm/fpu/api.h>
#include <asm/cpufeature.h>
#include <asm/processor.h>
#include <asm/intel-family.h>
#ifdef CONFIG_AS_SSSE3
asmlinkage void hchacha20_ssse3(u8 *derived_key, const u8 *nonce, const u8 *key);
asmlinkage void chacha20_ssse3(u8 *out, const u8 *in, const size_t len, const u32 key[8], const u32 counter[4]);
#endif
#ifdef CONFIG_AS_AVX2
asmlinkage void chacha20_avx2(u8 *out, const u8 *in, const size_t len, const u32 key[8], const u32 counter[4]);
#endif
#ifdef CONFIG_AS_AVX512
asmlinkage void chacha20_avx512(u8 *out, const u8 *in, const size_t len, const u32 key[8], const u32 counter[4]);
asmlinkage void chacha20_avx512vl(u8 *out, const u8 *in, const size_t len, const u32 key[8], const u32 counter[4]);
#endif

static bool chacha20_use_ssse3 __ro_after_init;
static bool chacha20_use_avx2 __ro_after_init;
static bool chacha20_use_avx512 __ro_after_init;
static bool chacha20_use_avx512vl __ro_after_init;

void __init chacha20_fpu_init(void)
{
#ifndef CONFIG_UML
	chacha20_use_ssse3 = boot_cpu_has(X86_FEATURE_SSSE3);
	chacha20_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_AVX2) &&
			    cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
#ifndef COMPAT_CANNOT_USE_AVX512
	chacha20_use_avx512 = boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_AVX2) && boot_cpu_has(X86_FEATURE_AVX512F) &&
			      cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM | XFEATURE_MASK_AVX512, NULL) &&
			      boot_cpu_data.x86_model != INTEL_FAM6_SKYLAKE_X;
	chacha20_use_avx512vl = boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_AVX2) && boot_cpu_has(X86_FEATURE_AVX512F) && boot_cpu_has(X86_FEATURE_AVX512VL) &&
				cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM | XFEATURE_MASK_AVX512, NULL);
#endif
#endif
}
#elif defined(CONFIG_ARM) || defined(CONFIG_ARM64)
asmlinkage void chacha20_arm(u8 *out, const u8 *in, const size_t len, const u32 key[8], const u32 counter[4]);
#if IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (!defined(__LINUX_ARM_ARCH__) || __LINUX_ARM_ARCH__ >= 7)
#define ARM_USE_NEON
#include <asm/hwcap.h>
#include <asm/neon.h>
asmlinkage void chacha20_neon(u8 *out, const u8 *in, const size_t len, const u32 key[8], const u32 counter[4]);
#endif
static bool chacha20_use_neon __ro_after_init;
void __init chacha20_fpu_init(void)
{
#if defined(CONFIG_ARM64)
	chacha20_use_neon = elf_hwcap & HWCAP_ASIMD;
#elif defined(CONFIG_ARM)
	chacha20_use_neon = elf_hwcap & HWCAP_NEON;
#endif
}
#elif defined(CONFIG_MIPS) && defined(CONFIG_CPU_MIPS32_R2)
asmlinkage void chacha20_mips(u8 *out, const u8 *in, const size_t len, const u32 key[8], const u32 counter[4]);
void __init chacha20_fpu_init(void) { }
#else
void __init chacha20_fpu_init(void) { }
#endif

#define EXPAND_32_BYTE_K 0x61707865U, 0x3320646eU, 0x79622d32U, 0x6b206574U

#define QUARTER_ROUND(x, a, b, c, d) ( \
	x[a] += x[b], \
	x[d] = rol32((x[d] ^ x[a]), 16), \
	x[c] += x[d], \
	x[b] = rol32((x[b] ^ x[c]), 12), \
	x[a] += x[b], \
	x[d] = rol32((x[d] ^ x[a]), 8), \
	x[c] += x[d], \
	x[b] = rol32((x[b] ^ x[c]), 7) \
)

#define C(i, j) (i * 4 + j)

#define DOUBLE_ROUND(x) ( \
	/* Column Round */ \
	QUARTER_ROUND(x, C(0, 0), C(1, 0), C(2, 0), C(3, 0)), \
	QUARTER_ROUND(x, C(0, 1), C(1, 1), C(2, 1), C(3, 1)), \
	QUARTER_ROUND(x, C(0, 2), C(1, 2), C(2, 2), C(3, 2)), \
	QUARTER_ROUND(x, C(0, 3), C(1, 3), C(2, 3), C(3, 3)), \
	/* Diagonal Round */ \
	QUARTER_ROUND(x, C(0, 0), C(1, 1), C(2, 2), C(3, 3)), \
	QUARTER_ROUND(x, C(0, 1), C(1, 2), C(2, 3), C(3, 0)), \
	QUARTER_ROUND(x, C(0, 2), C(1, 3), C(2, 0), C(3, 1)), \
	QUARTER_ROUND(x, C(0, 3), C(1, 0), C(2, 1), C(3, 2)) \
)

#define TWENTY_ROUNDS(x) ( \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x), \
	DOUBLE_ROUND(x) \
)

static void chacha20_block_generic(__le32 *stream, u32 *state)
{
	u32 x[CHACHA20_BLOCK_SIZE / sizeof(u32)];
	int i;

	for (i = 0; i < ARRAY_SIZE(x); ++i)
		x[i] = state[i];

	TWENTY_ROUNDS(x);

	for (i = 0; i < ARRAY_SIZE(x); ++i)
		stream[i] = cpu_to_le32(x[i] + state[i]);

	++state[12];
}

static void chacha20_generic(u8 *out, const u8 *in, u32 len, const u32 key[8], const u32 counter[4])
{
	__le32 buf[CHACHA20_BLOCK_SIZE / sizeof(__le32)];
	u32 x[] = {
		EXPAND_32_BYTE_K,
		key[0], key[1], key[2], key[3],
		key[4], key[5], key[6], key[7],
		counter[0], counter[1], counter[2], counter[3]
	};

	if (out != in)
		memmove(out, in, len);

	while (len >= CHACHA20_BLOCK_SIZE) {
		chacha20_block_generic(buf, x);
		crypto_xor(out, (u8 *)buf, CHACHA20_BLOCK_SIZE);
		len -= CHACHA20_BLOCK_SIZE;
		out += CHACHA20_BLOCK_SIZE;
	}
	if (len) {
		chacha20_block_generic(buf, x);
		crypto_xor(out, (u8 *)buf, len);
	}
}

void chacha20(struct chacha20_ctx *state, u8 *dst, const u8 *src, u32 len, simd_context_t simd_context)
{
	if (simd_context != HAVE_FULL_SIMD
#if defined(CONFIG_X86_64)
		|| !chacha20_use_ssse3

#elif defined(ARM_USE_NEON)
		|| !chacha20_use_neon
#endif
	)
		goto no_simd;

#if defined(CONFIG_X86_64)
#ifdef CONFIG_AS_AVX512
	if (chacha20_use_avx512) {
		chacha20_avx512(dst, src, len, state->key, state->counter);
		goto out;
	}
	if (chacha20_use_avx512vl) {
		chacha20_avx512vl(dst, src, len, state->key, state->counter);
		goto out;
	}
#endif
#ifdef CONFIG_AS_AVX2
	if (chacha20_use_avx2) {
		chacha20_avx2(dst, src, len, state->key, state->counter);
		goto out;
	}
#endif
#ifdef CONFIG_AS_SSSE3
	chacha20_ssse3(dst, src, len, state->key, state->counter);
	goto out;
#endif
#elif defined(ARM_USE_NEON)
	chacha20_neon(dst, src, len, state->key, state->counter);
	goto out;
#endif

no_simd:
#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
	chacha20_arm(dst, src, len, state->key, state->counter);
	goto out;
#elif defined(CONFIG_MIPS) && defined(CONFIG_CPU_MIPS32_R2)
	chacha20_mips(dst, src, len, state->key, state->counter);
	goto out;
#endif

	chacha20_generic(dst, src, len, state->key, state->counter);
	goto out;

out:
	state->counter[0] += (len + 63) / 64;
}

static void hchacha20_generic(u8 derived_key[CHACHA20_KEY_SIZE], const u8 nonce[HCHACHA20_NONCE_SIZE], const u8 key[HCHACHA20_KEY_SIZE])
{
	__le32 *out = (__force __le32 *)derived_key;
	u32 x[] = {
		EXPAND_32_BYTE_K,
		get_unaligned_le32(key + 0), get_unaligned_le32(key + 4), get_unaligned_le32(key + 8), get_unaligned_le32(key + 12),
		get_unaligned_le32(key + 16), get_unaligned_le32(key + 20), get_unaligned_le32(key + 24), get_unaligned_le32(key + 28),
		get_unaligned_le32(nonce + 0), get_unaligned_le32(nonce + 4), get_unaligned_le32(nonce +  8), get_unaligned_le32(nonce + 12)
	};

	TWENTY_ROUNDS(x);

	out[0] = cpu_to_le32(x[0]);
	out[1] = cpu_to_le32(x[1]);
	out[2] = cpu_to_le32(x[2]);
	out[3] = cpu_to_le32(x[3]);
	out[4] = cpu_to_le32(x[12]);
	out[5] = cpu_to_le32(x[13]);
	out[6] = cpu_to_le32(x[14]);
	out[7] = cpu_to_le32(x[15]);
}

void hchacha20(u8 derived_key[CHACHA20_KEY_SIZE], const u8 nonce[HCHACHA20_NONCE_SIZE], const u8 key[HCHACHA20_KEY_SIZE], simd_context_t simd_context)
{
#if defined(CONFIG_X86_64) && defined(CONFIG_AS_SSSE3)
	if (simd_context == HAVE_FULL_SIMD && chacha20_use_ssse3) {
		hchacha20_ssse3(derived_key, nonce, key);
		return;
	}
#endif
	hchacha20_generic(derived_key, nonce, key);
}