aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/src/crypto/zinc/poly1305/poly1305.c
blob: dd2e1a39054f05983b5b05f15920c4c873f26c9e (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
// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 *
 * Implementation of the Poly1305 message authenticator.
 *
 * Information: https://cr.yp.to/mac.html
 */

#include <zinc/poly1305.h>
#include "../selftest/run.h"

#include <asm/unaligned.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/init.h>

#if defined(CONFIG_ZINC_ARCH_ARM) || defined(CONFIG_ZINC_ARCH_ARM64) || defined(CONFIG_ZINC_ARCH_PPC32) || defined(CONFIG_ZINC_ARCH_PPC64)
#if defined(CONFIG_ZINC_ARCH_ARM64) || defined(CONFIG_ZINC_ARCH_PPC64)
struct poly1305_arch_internal {
	union {
		u32 h[5];
		struct {
			u64 h0, h1, h2;
		};
	};
	u64 is_base2_26;
	u64 r[2];
};
#elif defined(CONFIG_ZINC_ARCH_ARM) || defined(CONFIG_ZINC_ARCH_PPC32)
struct poly1305_arch_internal {
	union {
		u32 h[5];
		struct {
			u64 h0, h1;
			u32 h2;
		} __packed;
	};
	u32 r[4];
	u32 is_base2_26;
};
#endif
/* The NEON and AVX code uses base 2^26, while the scalar code uses base 2^64 on 64-bit
 * and base 2^32 on 32-bit. If we hit the unfortunate situation of using NEON or AVX
 * and then having to go back to scalar -- because the user is silly and has
 * called the update function from two separate contexts -- then we need to
 * convert back to the original base before proceeding. The below function is
 * written for 64-bit integers, and so we have to swap words at the end on
 * big-endian 32-bit. It is possible to reason that the initial reduction below
 * is sufficient given the implementation invariants. However, for an avoidance
 * of doubt and because this is not performance critical, we do the full
 * reduction anyway.
 */
static void convert_to_base2_64(void *ctx)
{
	struct poly1305_arch_internal *state = ctx;
	u32 cy;

	if (!(IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || IS_ENABLED(CONFIG_AVX)) || !state->is_base2_26)
		return;

	cy = state->h[0] >> 26; state->h[0] &= 0x3ffffff; state->h[1] += cy;
	cy = state->h[1] >> 26; state->h[1] &= 0x3ffffff; state->h[2] += cy;
	cy = state->h[2] >> 26; state->h[2] &= 0x3ffffff; state->h[3] += cy;
	cy = state->h[3] >> 26; state->h[3] &= 0x3ffffff; state->h[4] += cy;
	state->h0 = ((u64)state->h[2] << 52) | ((u64)state->h[1] << 26) | state->h[0];
	state->h1 = ((u64)state->h[4] << 40) | ((u64)state->h[3] << 14) | (state->h[2] >> 12);
	state->h2 = state->h[4] >> 24;
	if ((IS_ENABLED(CONFIG_ZINC_ARCH_ARM) || IS_ENABLED(CONFIG_ZINC_ARCH_PPC32)) &&
	    IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) {
		state->h0 = rol64(state->h0, 32);
		state->h1 = rol64(state->h1, 32);
	}
#define ULT(a, b) ((a ^ ((a ^ b) | ((a - b) ^ b))) >> (sizeof(a) * 8 - 1))
	cy = (state->h2 >> 2) + (state->h2 & ~3ULL);
	state->h2 &= 3;
	state->h0 += cy;
	state->h1 += (cy = ULT(state->h0, cy));
	state->h2 += ULT(state->h1, cy);
#undef ULT
	state->is_base2_26 = 0;
}
#endif

#if defined(CONFIG_ZINC_ARCH_X86_64)
#include "poly1305-x86_64-glue.c"
#elif defined(CONFIG_ZINC_ARCH_ARM) || defined(CONFIG_ZINC_ARCH_ARM64)
#include "poly1305-arm-glue.c"
#elif defined(CONFIG_ZINC_ARCH_MIPS) || defined(CONFIG_ZINC_ARCH_MIPS64)
#include "poly1305-mips-glue.c"
#elif defined(CONFIG_ZINC_ARCH_PPC32) || defined(CONFIG_ZINC_ARCH_PPC64)
#include "poly1305-ppc-glue.c"
#else
static inline bool poly1305_init_arch(void *ctx,
				      const u8 key[POLY1305_KEY_SIZE])
{
	return false;
}
static inline bool poly1305_blocks_arch(void *ctx, const u8 *input,
					size_t len, const u32 padbit,
					simd_context_t *simd_context)
{
	return false;
}
static inline bool poly1305_emit_arch(void *ctx, u8 mac[POLY1305_MAC_SIZE],
				      const u32 nonce[4],
				      simd_context_t *simd_context)
{
	return false;
}
static bool *const poly1305_nobs[] __initconst = { };
static void __init poly1305_fpu_init(void)
{
}
#endif

#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
#include "poly1305-donna64.c"
#else
#include "poly1305-donna32.c"
#endif

void poly1305_init(struct poly1305_ctx *ctx, const u8 key[POLY1305_KEY_SIZE])
{
	ctx->nonce[0] = get_unaligned_le32(&key[16]);
	ctx->nonce[1] = get_unaligned_le32(&key[20]);
	ctx->nonce[2] = get_unaligned_le32(&key[24]);
	ctx->nonce[3] = get_unaligned_le32(&key[28]);

	if (!poly1305_init_arch(ctx->opaque, key))
		poly1305_init_generic(ctx->opaque, key);

	ctx->num = 0;
}
EXPORT_SYMBOL(poly1305_init);

static inline void poly1305_blocks(void *ctx, const u8 *input, const size_t len,
				   const u32 padbit,
				   simd_context_t *simd_context)
{
	if (!poly1305_blocks_arch(ctx, input, len, padbit, simd_context))
		poly1305_blocks_generic(ctx, input, len, padbit);
}

static inline void poly1305_emit(void *ctx, u8 mac[POLY1305_KEY_SIZE],
				 const u32 nonce[4],
				 simd_context_t *simd_context)
{
	if (!poly1305_emit_arch(ctx, mac, nonce, simd_context))
		poly1305_emit_generic(ctx, mac, nonce);
}

void poly1305_update(struct poly1305_ctx *ctx, const u8 *input, size_t len,
		     simd_context_t *simd_context)
{
	const size_t num = ctx->num;
	size_t rem;

	if (num) {
		rem = POLY1305_BLOCK_SIZE - num;
		if (len < rem) {
			memcpy(ctx->data + num, input, len);
			ctx->num = num + len;
			return;
		}
		memcpy(ctx->data + num, input, rem);
		poly1305_blocks(ctx->opaque, ctx->data, POLY1305_BLOCK_SIZE, 1,
				simd_context);
		input += rem;
		len -= rem;
	}

	rem = len % POLY1305_BLOCK_SIZE;
	len -= rem;

	if (len >= POLY1305_BLOCK_SIZE) {
		poly1305_blocks(ctx->opaque, input, len, 1, simd_context);
		input += len;
	}

	if (rem)
		memcpy(ctx->data, input, rem);

	ctx->num = rem;
}
EXPORT_SYMBOL(poly1305_update);

void poly1305_final(struct poly1305_ctx *ctx, u8 mac[POLY1305_MAC_SIZE],
		    simd_context_t *simd_context)
{
	size_t num = ctx->num;

	if (num) {
		ctx->data[num++] = 1;
		while (num < POLY1305_BLOCK_SIZE)
			ctx->data[num++] = 0;
		poly1305_blocks(ctx->opaque, ctx->data, POLY1305_BLOCK_SIZE, 0,
				simd_context);
	}

	poly1305_emit(ctx->opaque, mac, ctx->nonce, simd_context);

	memzero_explicit(ctx, sizeof(*ctx));
}
EXPORT_SYMBOL(poly1305_final);

#include "../selftest/poly1305.c"

static bool nosimd __initdata = false;

#ifndef COMPAT_ZINC_IS_A_MODULE
int __init poly1305_mod_init(void)
#else
static int __init mod_init(void)
#endif
{
	if (!nosimd)
		poly1305_fpu_init();
	if (!selftest_run("poly1305", poly1305_selftest, poly1305_nobs,
			  ARRAY_SIZE(poly1305_nobs)))
		return -ENOTRECOVERABLE;
	return 0;
}

#ifdef COMPAT_ZINC_IS_A_MODULE
static void __exit mod_exit(void)
{
}

module_param(nosimd, bool, 0);
module_init(mod_init);
module_exit(mod_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Poly1305 one-time authenticator");
MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
#endif