xref: /freebsd/sys/dev/wg/wg_crypto.c (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
1 /* SPDX-License-Identifier: MIT
2  *
3  * Copyright (C) 2015-2021 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
4  * Copyright (c) 2022 The FreeBSD Foundation
5  */
6 
7 #include <sys/types.h>
8 #include <sys/systm.h>
9 #include <sys/endian.h>
10 #include <sys/mbuf.h>
11 #include <opencrypto/cryptodev.h>
12 
13 #include "crypto.h"
14 
15 static crypto_session_t chacha20_poly1305_sid;
16 
17 #ifdef COMPAT_NEED_BLAKE2S
18 #ifndef ARRAY_SIZE
19 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
20 #endif
21 #ifndef DIV_ROUND_UP
22 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
23 #endif
24 
25 #define le32_to_cpup(a) le32toh(*(a))
26 #define cpu_to_le32(a) htole32(a)
27 
28 static inline void cpu_to_le32_array(uint32_t *buf, unsigned int words)
29 {
30         while (words--) {
31 		*buf = cpu_to_le32(*buf);
32 		++buf;
33 	}
34 }
35 static inline void le32_to_cpu_array(uint32_t *buf, unsigned int words)
36 {
37         while (words--) {
38 		*buf = le32_to_cpup(buf);
39 		++buf;
40         }
41 }
42 static inline uint32_t ror32(uint32_t word, unsigned int shift)
43 {
44 	return (word >> (shift & 31)) | (word << ((-shift) & 31));
45 }
46 
47 static const uint32_t blake2s_iv[8] = {
48 	0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL,
49 	0x510E527FUL, 0x9B05688CUL, 0x1F83D9ABUL, 0x5BE0CD19UL
50 };
51 
52 static const uint8_t blake2s_sigma[10][16] = {
53 	{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
54 	{ 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 },
55 	{ 11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 },
56 	{ 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 },
57 	{ 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 },
58 	{ 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 },
59 	{ 12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11 },
60 	{ 13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10 },
61 	{ 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5 },
62 	{ 10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0 },
63 };
64 
65 static inline void blake2s_set_lastblock(struct blake2s_state *state)
66 {
67 	state->f[0] = -1;
68 }
69 
70 static inline void blake2s_increment_counter(struct blake2s_state *state,
71 					     const uint32_t inc)
72 {
73 	state->t[0] += inc;
74 	state->t[1] += (state->t[0] < inc);
75 }
76 
77 static inline void blake2s_init_param(struct blake2s_state *state,
78 				      const uint32_t param)
79 {
80 	int i;
81 
82 	memset(state, 0, sizeof(*state));
83 	for (i = 0; i < 8; ++i)
84 		state->h[i] = blake2s_iv[i];
85 	state->h[0] ^= param;
86 }
87 
88 void blake2s_init(struct blake2s_state *state, const size_t outlen)
89 {
90 	blake2s_init_param(state, 0x01010000 | outlen);
91 	state->outlen = outlen;
92 }
93 
94 void blake2s_init_key(struct blake2s_state *state, const size_t outlen,
95 		      const uint8_t *key, const size_t keylen)
96 {
97 	uint8_t block[BLAKE2S_BLOCK_SIZE] = { 0 };
98 
99 	blake2s_init_param(state, 0x01010000 | keylen << 8 | outlen);
100 	state->outlen = outlen;
101 	memcpy(block, key, keylen);
102 	blake2s_update(state, block, BLAKE2S_BLOCK_SIZE);
103 	explicit_bzero(block, BLAKE2S_BLOCK_SIZE);
104 }
105 
106 static inline void blake2s_compress(struct blake2s_state *state,
107 				    const uint8_t *block, size_t nblocks,
108 				    const uint32_t inc)
109 {
110 	uint32_t m[16];
111 	uint32_t v[16];
112 	int i;
113 
114 	while (nblocks > 0) {
115 		blake2s_increment_counter(state, inc);
116 		memcpy(m, block, BLAKE2S_BLOCK_SIZE);
117 		le32_to_cpu_array(m, ARRAY_SIZE(m));
118 		memcpy(v, state->h, 32);
119 		v[ 8] = blake2s_iv[0];
120 		v[ 9] = blake2s_iv[1];
121 		v[10] = blake2s_iv[2];
122 		v[11] = blake2s_iv[3];
123 		v[12] = blake2s_iv[4] ^ state->t[0];
124 		v[13] = blake2s_iv[5] ^ state->t[1];
125 		v[14] = blake2s_iv[6] ^ state->f[0];
126 		v[15] = blake2s_iv[7] ^ state->f[1];
127 
128 #define G(r, i, a, b, c, d) do { \
129 	a += b + m[blake2s_sigma[r][2 * i + 0]]; \
130 	d = ror32(d ^ a, 16); \
131 	c += d; \
132 	b = ror32(b ^ c, 12); \
133 	a += b + m[blake2s_sigma[r][2 * i + 1]]; \
134 	d = ror32(d ^ a, 8); \
135 	c += d; \
136 	b = ror32(b ^ c, 7); \
137 } while (0)
138 
139 #define ROUND(r) do { \
140 	G(r, 0, v[0], v[ 4], v[ 8], v[12]); \
141 	G(r, 1, v[1], v[ 5], v[ 9], v[13]); \
142 	G(r, 2, v[2], v[ 6], v[10], v[14]); \
143 	G(r, 3, v[3], v[ 7], v[11], v[15]); \
144 	G(r, 4, v[0], v[ 5], v[10], v[15]); \
145 	G(r, 5, v[1], v[ 6], v[11], v[12]); \
146 	G(r, 6, v[2], v[ 7], v[ 8], v[13]); \
147 	G(r, 7, v[3], v[ 4], v[ 9], v[14]); \
148 } while (0)
149 		ROUND(0);
150 		ROUND(1);
151 		ROUND(2);
152 		ROUND(3);
153 		ROUND(4);
154 		ROUND(5);
155 		ROUND(6);
156 		ROUND(7);
157 		ROUND(8);
158 		ROUND(9);
159 
160 #undef G
161 #undef ROUND
162 
163 		for (i = 0; i < 8; ++i)
164 			state->h[i] ^= v[i] ^ v[i + 8];
165 
166 		block += BLAKE2S_BLOCK_SIZE;
167 		--nblocks;
168 	}
169 }
170 
171 void blake2s_update(struct blake2s_state *state, const uint8_t *in, size_t inlen)
172 {
173 	const size_t fill = BLAKE2S_BLOCK_SIZE - state->buflen;
174 
175 	if (!inlen)
176 		return;
177 	if (inlen > fill) {
178 		memcpy(state->buf + state->buflen, in, fill);
179 		blake2s_compress(state, state->buf, 1, BLAKE2S_BLOCK_SIZE);
180 		state->buflen = 0;
181 		in += fill;
182 		inlen -= fill;
183 	}
184 	if (inlen > BLAKE2S_BLOCK_SIZE) {
185 		const size_t nblocks = DIV_ROUND_UP(inlen, BLAKE2S_BLOCK_SIZE);
186 		/* Hash one less (full) block than strictly possible */
187 		blake2s_compress(state, in, nblocks - 1, BLAKE2S_BLOCK_SIZE);
188 		in += BLAKE2S_BLOCK_SIZE * (nblocks - 1);
189 		inlen -= BLAKE2S_BLOCK_SIZE * (nblocks - 1);
190 	}
191 	memcpy(state->buf + state->buflen, in, inlen);
192 	state->buflen += inlen;
193 }
194 
195 void blake2s_final(struct blake2s_state *state, uint8_t *out)
196 {
197 	blake2s_set_lastblock(state);
198 	memset(state->buf + state->buflen, 0,
199 	       BLAKE2S_BLOCK_SIZE - state->buflen); /* Padding */
200 	blake2s_compress(state, state->buf, 1, state->buflen);
201 	cpu_to_le32_array(state->h, ARRAY_SIZE(state->h));
202 	memcpy(out, state->h, state->outlen);
203 	explicit_bzero(state, sizeof(*state));
204 }
205 #endif
206 
207 static int
208 crypto_callback(struct cryptop *crp)
209 {
210 	return (0);
211 }
212 
213 int
214 chacha20poly1305_encrypt_mbuf(struct mbuf *m, const uint64_t nonce,
215 			      const uint8_t key[CHACHA20POLY1305_KEY_SIZE])
216 {
217 	static const char blank_tag[POLY1305_HASH_LEN];
218 	struct cryptop crp;
219 	int ret;
220 
221 	if (!m_append(m, POLY1305_HASH_LEN, blank_tag))
222 		return (ENOMEM);
223 	crypto_initreq(&crp, chacha20_poly1305_sid);
224 	crp.crp_op = CRYPTO_OP_ENCRYPT | CRYPTO_OP_COMPUTE_DIGEST;
225 	crp.crp_flags = CRYPTO_F_IV_SEPARATE | CRYPTO_F_CBIMM;
226 	crypto_use_mbuf(&crp, m);
227 	crp.crp_payload_length = m->m_pkthdr.len - POLY1305_HASH_LEN;
228 	crp.crp_digest_start = crp.crp_payload_length;
229 	le64enc(crp.crp_iv, nonce);
230 	crp.crp_cipher_key = key;
231 	crp.crp_callback = crypto_callback;
232 	ret = crypto_dispatch(&crp);
233 	crypto_destroyreq(&crp);
234 	return (ret);
235 }
236 
237 int
238 chacha20poly1305_decrypt_mbuf(struct mbuf *m, const uint64_t nonce,
239 			      const uint8_t key[CHACHA20POLY1305_KEY_SIZE])
240 {
241 	struct cryptop crp;
242 	int ret;
243 
244 	if (m->m_pkthdr.len < POLY1305_HASH_LEN)
245 		return (EMSGSIZE);
246 	crypto_initreq(&crp, chacha20_poly1305_sid);
247 	crp.crp_op = CRYPTO_OP_DECRYPT | CRYPTO_OP_VERIFY_DIGEST;
248 	crp.crp_flags = CRYPTO_F_IV_SEPARATE | CRYPTO_F_CBIMM;
249 	crypto_use_mbuf(&crp, m);
250 	crp.crp_payload_length = m->m_pkthdr.len - POLY1305_HASH_LEN;
251 	crp.crp_digest_start = crp.crp_payload_length;
252 	le64enc(crp.crp_iv, nonce);
253 	crp.crp_cipher_key = key;
254 	crp.crp_callback = crypto_callback;
255 	ret = crypto_dispatch(&crp);
256 	crypto_destroyreq(&crp);
257 	if (ret)
258 		return (ret);
259 	m_adj(m, -POLY1305_HASH_LEN);
260 	return (0);
261 }
262 
263 int
264 crypto_init(void)
265 {
266 	struct crypto_session_params csp = {
267 		.csp_mode = CSP_MODE_AEAD,
268 		.csp_ivlen = sizeof(uint64_t),
269 		.csp_cipher_alg = CRYPTO_CHACHA20_POLY1305,
270 		.csp_cipher_klen = CHACHA20POLY1305_KEY_SIZE,
271 		.csp_flags = CSP_F_SEPARATE_AAD | CSP_F_SEPARATE_OUTPUT
272 	};
273 	int ret = crypto_newsession(&chacha20_poly1305_sid, &csp, CRYPTOCAP_F_SOFTWARE);
274 	if (ret != 0)
275 		return (ret);
276 	return (0);
277 }
278 
279 void
280 crypto_deinit(void)
281 {
282 	crypto_freesession(chacha20_poly1305_sid);
283 }
284