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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libcrypto/evp/e_chacha20poly1305.c	Lines:	78	101	77.2 %
Date:	2017-11-13	Branches:	20	32	62.5 %


/* $OpenBSD: e_chacha20poly1305.c,v 1.18 2017/08/28 17:48:02 jsing Exp $ */

/*
 * Copyright (c) 2015 Reyk Floter <reyk@openbsd.org>
 * Copyright (c) 2014, Google Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdint.h>
#include <string.h>

#include <openssl/opensslconf.h>

#if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)

#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/chacha.h>
#include <openssl/poly1305.h>

#include "evp_locl.h"

#define POLY1305_TAG_LEN 16

#define CHACHA20_CONSTANT_LEN 4
#define CHACHA20_IV_LEN 8
#define CHACHA20_NONCE_LEN (CHACHA20_CONSTANT_LEN + CHACHA20_IV_LEN)

struct aead_chacha20_poly1305_ctx {
	unsigned char key[32];
	unsigned char tag_len;
};

static int
aead_chacha20_poly1305_init(EVP_AEAD_CTX *ctx, const unsigned char *key,
    size_t key_len, size_t tag_len)
{
	struct aead_chacha20_poly1305_ctx *c20_ctx;

	if (tag_len == 0)
		tag_len = POLY1305_TAG_LEN;

	if (tag_len > POLY1305_TAG_LEN) {
		EVPerror(EVP_R_TOO_LARGE);
		return 0;
	}

	/* Internal error - EVP_AEAD_CTX_init should catch this. */
	if (key_len != sizeof(c20_ctx->key))
		return 0;

	c20_ctx = malloc(sizeof(struct aead_chacha20_poly1305_ctx));
	if (c20_ctx == NULL)
		return 0;

	memcpy(&c20_ctx->key[0], key, key_len);
	c20_ctx->tag_len = tag_len;
	ctx->aead_state = c20_ctx;

	return 1;
}

static void
aead_chacha20_poly1305_cleanup(EVP_AEAD_CTX *ctx)
{
	struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;

	freezero(c20_ctx, sizeof(*c20_ctx));
}

static void
poly1305_update_with_length(poly1305_state *poly1305,
    const unsigned char *data, size_t data_len)
{
	size_t j = data_len;
	unsigned char length_bytes[8];
	unsigned i;

	for (i = 0; i < sizeof(length_bytes); i++) {
		length_bytes[i] = j;
		j >>= 8;
	}

	if (data != NULL)
		CRYPTO_poly1305_update(poly1305, data, data_len);
	CRYPTO_poly1305_update(poly1305, length_bytes, sizeof(length_bytes));
}

static void
poly1305_update_with_pad16(poly1305_state *poly1305,
    const unsigned char *data, size_t data_len)
{
	static const unsigned char zero_pad16[16];
	size_t pad_len;

	CRYPTO_poly1305_update(poly1305, data, data_len);

	/* pad16() is defined in RFC 7539 2.8.1. */
	if ((pad_len = data_len % 16) == 0)
		return;

	CRYPTO_poly1305_update(poly1305, zero_pad16, 16 - pad_len);
}

static int
aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, unsigned char *out,
    size_t *out_len, size_t max_out_len, const unsigned char *nonce,
    size_t nonce_len, const unsigned char *in, size_t in_len,
    const unsigned char *ad, size_t ad_len)
{
	const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
	unsigned char poly1305_key[32];
	poly1305_state poly1305;
	const unsigned char *iv;
	const uint64_t in_len_64 = in_len;
	uint64_t ctr;

	/* The underlying ChaCha implementation may not overflow the block
	 * counter into the second counter word. Therefore we disallow
	 * individual operations that work on more than 2TB at a time.
	 * in_len_64 is needed because, on 32-bit platforms, size_t is only
	 * 32-bits and this produces a warning because it's always false.
	 * Casting to uint64_t inside the conditional is not sufficient to stop
	 * the warning. */
	if (in_len_64 >= (1ULL << 32) * 64 - 64) {
		EVPerror(EVP_R_TOO_LARGE);
		return 0;
	}

	if (max_out_len < in_len + c20_ctx->tag_len) {
		EVPerror(EVP_R_BUFFER_TOO_SMALL);
		return 0;
	}

	if (nonce_len != ctx->aead->nonce_len) {
		EVPerror(EVP_R_IV_TOO_LARGE);
		return 0;
	}

	ctr = (uint64_t)(nonce[0] | nonce[1] << 8 |
	    nonce[2] << 16 | nonce[3] << 24) << 32;
	iv = nonce + CHACHA20_CONSTANT_LEN;

	memset(poly1305_key, 0, sizeof(poly1305_key));
	CRYPTO_chacha_20(poly1305_key, poly1305_key,
	    sizeof(poly1305_key), c20_ctx->key, iv, ctr);

	CRYPTO_poly1305_init(&poly1305, poly1305_key);
	poly1305_update_with_pad16(&poly1305, ad, ad_len);
	CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, iv, ctr + 1);
	poly1305_update_with_pad16(&poly1305, out, in_len);
	poly1305_update_with_length(&poly1305, NULL, ad_len);
	poly1305_update_with_length(&poly1305, NULL, in_len);

	if (c20_ctx->tag_len != POLY1305_TAG_LEN) {
		unsigned char tag[POLY1305_TAG_LEN];
		CRYPTO_poly1305_finish(&poly1305, tag);
		memcpy(out + in_len, tag, c20_ctx->tag_len);
		*out_len = in_len + c20_ctx->tag_len;
		return 1;
	}

	CRYPTO_poly1305_finish(&poly1305, out + in_len);
	*out_len = in_len + POLY1305_TAG_LEN;
	return 1;
}

static int
aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, unsigned char *out,
    size_t *out_len, size_t max_out_len, const unsigned char *nonce,
    size_t nonce_len, const unsigned char *in, size_t in_len,
    const unsigned char *ad, size_t ad_len)
{
	const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
	unsigned char mac[POLY1305_TAG_LEN];
	unsigned char poly1305_key[32];
	const unsigned char *iv = nonce;
	poly1305_state poly1305;
	const uint64_t in_len_64 = in_len;
	size_t plaintext_len;
	uint64_t ctr = 0;

	if (in_len < c20_ctx->tag_len) {
		EVPerror(EVP_R_BAD_DECRYPT);
		return 0;
	}

	/* The underlying ChaCha implementation may not overflow the block
	 * counter into the second counter word. Therefore we disallow
	 * individual operations that work on more than 2TB at a time.
	 * in_len_64 is needed because, on 32-bit platforms, size_t is only
	 * 32-bits and this produces a warning because it's always false.
	 * Casting to uint64_t inside the conditional is not sufficient to stop
	 * the warning. */
	if (in_len_64 >= (1ULL << 32) * 64 - 64) {
		EVPerror(EVP_R_TOO_LARGE);
		return 0;
	}

	if (nonce_len != ctx->aead->nonce_len) {
		EVPerror(EVP_R_IV_TOO_LARGE);
		return 0;
	}

	plaintext_len = in_len - c20_ctx->tag_len;

	if (max_out_len < plaintext_len) {
		EVPerror(EVP_R_BUFFER_TOO_SMALL);
		return 0;
	}

	ctr = (uint64_t)(nonce[0] | nonce[1] << 8 |
	    nonce[2] << 16 | nonce[3] << 24) << 32;
	iv = nonce + CHACHA20_CONSTANT_LEN;

	memset(poly1305_key, 0, sizeof(poly1305_key));
	CRYPTO_chacha_20(poly1305_key, poly1305_key,
	    sizeof(poly1305_key), c20_ctx->key, iv, ctr);

	CRYPTO_poly1305_init(&poly1305, poly1305_key);
	poly1305_update_with_pad16(&poly1305, ad, ad_len);
	poly1305_update_with_pad16(&poly1305, in, plaintext_len);
	poly1305_update_with_length(&poly1305, NULL, ad_len);
	poly1305_update_with_length(&poly1305, NULL, plaintext_len);

	CRYPTO_poly1305_finish(&poly1305, mac);

	if (timingsafe_memcmp(mac, in + plaintext_len, c20_ctx->tag_len) != 0) {
		EVPerror(EVP_R_BAD_DECRYPT);
		return 0;
	}

	CRYPTO_chacha_20(out, in, plaintext_len, c20_ctx->key, iv, ctr + 1);
	*out_len = plaintext_len;
	return 1;
}

/* RFC 7539 */
static const EVP_AEAD aead_chacha20_poly1305 = {
	.key_len = 32,
	.nonce_len = CHACHA20_NONCE_LEN,
	.overhead = POLY1305_TAG_LEN,
	.max_tag_len = POLY1305_TAG_LEN,

	.init = aead_chacha20_poly1305_init,
	.cleanup = aead_chacha20_poly1305_cleanup,
	.seal = aead_chacha20_poly1305_seal,
	.open = aead_chacha20_poly1305_open,
};

const EVP_AEAD *
EVP_aead_chacha20_poly1305()
{
	return &aead_chacha20_poly1305;
}

#endif  /* !OPENSSL_NO_CHACHA && !OPENSSL_NO_POLY1305 */


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: e_chacha20poly1305.c,v 1.18 2017/08/28 17:48:02 jsing Exp $ */
2
3			/*
4			* Copyright (c) 2015 Reyk Floter <reyk@openbsd.org>
5			* Copyright (c) 2014, Google Inc.
6			*
7			* Permission to use, copy, modify, and/or distribute this software for any
8			* purpose with or without fee is hereby granted, provided that the above
9			* copyright notice and this permission notice appear in all copies.
10			*
11			* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
14			* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15			* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
16			* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
17			* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18			*/
19
20			#include <stdint.h>
21			#include <string.h>
22
23			#include <openssl/opensslconf.h>
24
25			#if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)
26
27			#include <openssl/err.h>
28			#include <openssl/evp.h>
29			#include <openssl/chacha.h>
30			#include <openssl/poly1305.h>
31
32			#include "evp_locl.h"
33
34			#define POLY1305_TAG_LEN 16
35
36			#define CHACHA20_CONSTANT_LEN 4
37			#define CHACHA20_IV_LEN 8
38			#define CHACHA20_NONCE_LEN (CHACHA20_CONSTANT_LEN + CHACHA20_IV_LEN)
39
40			struct aead_chacha20_poly1305_ctx {
41			unsigned char key[32];
42			unsigned char tag_len;
43			};
44
45			static int
46			aead_chacha20_poly1305_init(EVP_AEAD_CTX ctx, const unsigned char key,
47			size_t key_len, size_t tag_len)
48			{
49			struct aead_chacha20_poly1305_ctx *c20_ctx;
50
51	✓✓	72	if (tag_len == 0)
52		24	tag_len = POLY1305_TAG_LEN;
53
54	✗✓	36	if (tag_len > POLY1305_TAG_LEN) {
55			EVPerror(EVP_R_TOO_LARGE);
56			return 0;
57			}
58
59			/* Internal error - EVP_AEAD_CTX_init should catch this. */
60	✗✓	36	if (key_len != sizeof(c20_ctx->key))
61			return 0;
62
63		36	c20_ctx = malloc(sizeof(struct aead_chacha20_poly1305_ctx));
64	✗✓	36	if (c20_ctx == NULL)
65			return 0;
66
67		36	memcpy(&c20_ctx->key[0], key, key_len);
68		36	c20_ctx->tag_len = tag_len;
69		36	ctx->aead_state = c20_ctx;
70
71		36	return 1;
72		36	}
73
74			static void
75			aead_chacha20_poly1305_cleanup(EVP_AEAD_CTX *ctx)
76			{
77		72	struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
78
79		36	freezero(c20_ctx, sizeof(*c20_ctx));
80		36	}
81
82			static void
83			poly1305_update_with_length(poly1305_state *poly1305,
84			const unsigned char *data, size_t data_len)
85			{
86			size_t j = data_len;
87		384	unsigned char length_bytes[8];
88			unsigned i;
89
90	✓✓	3456	for (i = 0; i < sizeof(length_bytes); i++) {
91		1536	length_bytes[i] = j;
92		1536	j >>= 8;
93			}
94
95	✗✓	192	if (data != NULL)
96			CRYPTO_poly1305_update(poly1305, data, data_len);
97		192	CRYPTO_poly1305_update(poly1305, length_bytes, sizeof(length_bytes));
98		192	}
99
100			static void
101			poly1305_update_with_pad16(poly1305_state *poly1305,
102			const unsigned char *data, size_t data_len)
103			{
104			static const unsigned char zero_pad16[16];
105			size_t pad_len;
106
107		384	CRYPTO_poly1305_update(poly1305, data, data_len);
108
109			/* pad16() is defined in RFC 7539 2.8.1. */
110	✓✓	192	if ((pad_len = data_len % 16) == 0)
111		57	return;
112
113		135	CRYPTO_poly1305_update(poly1305, zero_pad16, 16 - pad_len);
114		327	}
115
116			static int
117			aead_chacha20_poly1305_seal(const EVP_AEAD_CTX ctx, unsigned char out,
118			size_t out_len, size_t max_out_len, const unsigned char nonce,
119			size_t nonce_len, const unsigned char *in, size_t in_len,
120			const unsigned char *ad, size_t ad_len)
121			{
122		96	const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
123		48	unsigned char poly1305_key[32];
124		48	poly1305_state poly1305;
125			const unsigned char *iv;
126			const uint64_t in_len_64 = in_len;
127			uint64_t ctr;
128
129			/* The underlying ChaCha implementation may not overflow the block
130			* counter into the second counter word. Therefore we disallow
131			* individual operations that work on more than 2TB at a time.
132			* in_len_64 is needed because, on 32-bit platforms, size_t is only
133			* 32-bits and this produces a warning because it's always false.
134			* Casting to uint64_t inside the conditional is not sufficient to stop
135			* the warning. */
136	✗✓	48	if (in_len_64 >= (1ULL << 32) * 64 - 64) {
137			EVPerror(EVP_R_TOO_LARGE);
138			return 0;
139			}
140
141	✗✓	48	if (max_out_len < in_len + c20_ctx->tag_len) {
142			EVPerror(EVP_R_BUFFER_TOO_SMALL);
143			return 0;
144			}
145
146	✗✓	48	if (nonce_len != ctx->aead->nonce_len) {
147			EVPerror(EVP_R_IV_TOO_LARGE);
148			return 0;
149			}
150
151		144	ctr = (uint64_t)(nonce[0] \| nonce[1] << 8 \|
152		144	nonce[2] << 16 \| nonce[3] << 24) << 32;
153		48	iv = nonce + CHACHA20_CONSTANT_LEN;
154
155		48	memset(poly1305_key, 0, sizeof(poly1305_key));
156		48	CRYPTO_chacha_20(poly1305_key, poly1305_key,
157		48	sizeof(poly1305_key), c20_ctx->key, iv, ctr);
158
159		48	CRYPTO_poly1305_init(&poly1305, poly1305_key);
160		48	poly1305_update_with_pad16(&poly1305, ad, ad_len);
161		48	CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, iv, ctr + 1);
162		48	poly1305_update_with_pad16(&poly1305, out, in_len);
163		48	poly1305_update_with_length(&poly1305, NULL, ad_len);
164		48	poly1305_update_with_length(&poly1305, NULL, in_len);
165
166	✗✓	48	if (c20_ctx->tag_len != POLY1305_TAG_LEN) {
167			unsigned char tag[POLY1305_TAG_LEN];
168			CRYPTO_poly1305_finish(&poly1305, tag);
169			memcpy(out + in_len, tag, c20_ctx->tag_len);
170			*out_len = in_len + c20_ctx->tag_len;
171			return 1;
172			}
173
174		48	CRYPTO_poly1305_finish(&poly1305, out + in_len);
175		48	*out_len = in_len + POLY1305_TAG_LEN;
176		48	return 1;
177		48	}
178
179			static int
180			aead_chacha20_poly1305_open(const EVP_AEAD_CTX ctx, unsigned char out,
181			size_t out_len, size_t max_out_len, const unsigned char nonce,
182			size_t nonce_len, const unsigned char *in, size_t in_len,
183			const unsigned char *ad, size_t ad_len)
184			{
185		96	const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
186		48	unsigned char mac[POLY1305_TAG_LEN];
187		48	unsigned char poly1305_key[32];
188			const unsigned char *iv = nonce;
189		48	poly1305_state poly1305;
190			const uint64_t in_len_64 = in_len;
191			size_t plaintext_len;
192			uint64_t ctr = 0;
193
194	✗✓	48	if (in_len < c20_ctx->tag_len) {
195			EVPerror(EVP_R_BAD_DECRYPT);
196			return 0;
197			}
198
199			/* The underlying ChaCha implementation may not overflow the block
200			* counter into the second counter word. Therefore we disallow
201			* individual operations that work on more than 2TB at a time.
202			* in_len_64 is needed because, on 32-bit platforms, size_t is only
203			* 32-bits and this produces a warning because it's always false.
204			* Casting to uint64_t inside the conditional is not sufficient to stop
205			* the warning. */
206	✗✓	48	if (in_len_64 >= (1ULL << 32) * 64 - 64) {
207			EVPerror(EVP_R_TOO_LARGE);
208			return 0;
209			}
210
211	✗✓	48	if (nonce_len != ctx->aead->nonce_len) {
212			EVPerror(EVP_R_IV_TOO_LARGE);
213			return 0;
214			}
215
216		48	plaintext_len = in_len - c20_ctx->tag_len;
217
218	✗✓	48	if (max_out_len < plaintext_len) {
219			EVPerror(EVP_R_BUFFER_TOO_SMALL);
220			return 0;
221			}
222
223		144	ctr = (uint64_t)(nonce[0] \| nonce[1] << 8 \|
224		144	nonce[2] << 16 \| nonce[3] << 24) << 32;
225		48	iv = nonce + CHACHA20_CONSTANT_LEN;
226
227		48	memset(poly1305_key, 0, sizeof(poly1305_key));
228		48	CRYPTO_chacha_20(poly1305_key, poly1305_key,
229		48	sizeof(poly1305_key), c20_ctx->key, iv, ctr);
230
231		48	CRYPTO_poly1305_init(&poly1305, poly1305_key);
232		48	poly1305_update_with_pad16(&poly1305, ad, ad_len);
233		48	poly1305_update_with_pad16(&poly1305, in, plaintext_len);
234		48	poly1305_update_with_length(&poly1305, NULL, ad_len);
235		48	poly1305_update_with_length(&poly1305, NULL, plaintext_len);
236
237		48	CRYPTO_poly1305_finish(&poly1305, mac);
238
239	✓✓	48	if (timingsafe_memcmp(mac, in + plaintext_len, c20_ctx->tag_len) != 0) {
240		12	EVPerror(EVP_R_BAD_DECRYPT);
241		12	return 0;
242			}
243
244		36	CRYPTO_chacha_20(out, in, plaintext_len, c20_ctx->key, iv, ctr + 1);
245		36	*out_len = plaintext_len;
246		36	return 1;
247		48	}
248
249			/* RFC 7539 */
250			static const EVP_AEAD aead_chacha20_poly1305 = {
251			.key_len = 32,
252			.nonce_len = CHACHA20_NONCE_LEN,
253			.overhead = POLY1305_TAG_LEN,
254			.max_tag_len = POLY1305_TAG_LEN,
255
256			.init = aead_chacha20_poly1305_init,
257			.cleanup = aead_chacha20_poly1305_cleanup,
258			.seal = aead_chacha20_poly1305_seal,
259			.open = aead_chacha20_poly1305_open,
260			};
261
262			const EVP_AEAD *
263			EVP_aead_chacha20_poly1305()
264			{
265		48	return &aead_chacha20_poly1305;
266			}
267
268			#endif /* !OPENSSL_NO_CHACHA && !OPENSSL_NO_POLY1305 */