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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libc/crypt/arc4random.c	Lines:	65	68	95.6 %
Date:	2017-11-07	Branches:	30	38	78.9 %


/*	$OpenBSD: arc4random.c,v 1.54 2015/09/13 08:31:47 guenther Exp $	*/

/*
 * Copyright (c) 1996, David Mazieres <dm@uun.org>
 * Copyright (c) 2008, Damien Miller <djm@openbsd.org>
 * Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
 * Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org>
 *
 * Permission to use, copy, modify, and 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.
 */

/*
 * ChaCha based random number generator for OpenBSD.
 */

#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>

#define KEYSTREAM_ONLY
#include "chacha_private.h"

#define minimum(a, b) ((a) < (b) ? (a) : (b))

#if defined(__GNUC__) || defined(_MSC_VER)
#define inline __inline
#else				/* __GNUC__ || _MSC_VER */
#define inline
#endif				/* !__GNUC__ && !_MSC_VER */

#define KEYSZ	32
#define IVSZ	8
#define BLOCKSZ	64
#define RSBUFSZ	(16*BLOCKSZ)

/* Marked MAP_INHERIT_ZERO, so zero'd out in fork children. */
static struct _rs {
	size_t		rs_have;	/* valid bytes at end of rs_buf */
	size_t		rs_count;	/* bytes till reseed */
} *rs;

/* Maybe be preserved in fork children, if _rs_allocate() decides. */
static struct _rsx {
	chacha_ctx	rs_chacha;	/* chacha context for random keystream */
	u_char		rs_buf[RSBUFSZ];	/* keystream blocks */
} *rsx;

static inline int _rs_allocate(struct _rs **, struct _rsx **);
static inline void _rs_forkdetect(void);
#include "arc4random.h"

static inline void _rs_rekey(u_char *dat, size_t datlen);

static inline void
_rs_init(u_char *buf, size_t n)
{
	if (n < KEYSZ + IVSZ)
		return;

	if (rs == NULL) {
		if (_rs_allocate(&rs, &rsx) == -1)
			abort();
	}

	chacha_keysetup(&rsx->rs_chacha, buf, KEYSZ * 8, 0);
	chacha_ivsetup(&rsx->rs_chacha, buf + KEYSZ);
}

static void
_rs_stir(void)
{
	u_char rnd[KEYSZ + IVSZ];

	if (getentropy(rnd, sizeof rnd) == -1)
		_getentropy_fail();

	if (!rs)
		_rs_init(rnd, sizeof(rnd));
	else
		_rs_rekey(rnd, sizeof(rnd));
	explicit_bzero(rnd, sizeof(rnd));	/* discard source seed */

	/* invalidate rs_buf */
	rs->rs_have = 0;
	memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));

	rs->rs_count = 1600000;
}

static inline void
_rs_stir_if_needed(size_t len)
{
	_rs_forkdetect();
	if (!rs || rs->rs_count <= len)
		_rs_stir();
	if (rs->rs_count <= len)
		rs->rs_count = 0;
	else
		rs->rs_count -= len;
}

static inline void
_rs_rekey(u_char *dat, size_t datlen)
{
#ifndef KEYSTREAM_ONLY
	memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
#endif
	/* fill rs_buf with the keystream */
	chacha_encrypt_bytes(&rsx->rs_chacha, rsx->rs_buf,
	    rsx->rs_buf, sizeof(rsx->rs_buf));
	/* mix in optional user provided data */
	if (dat) {
		size_t i, m;

		m = minimum(datlen, KEYSZ + IVSZ);
		for (i = 0; i < m; i++)
			rsx->rs_buf[i] ^= dat[i];
	}
	/* immediately reinit for backtracking resistance */
	_rs_init(rsx->rs_buf, KEYSZ + IVSZ);
	memset(rsx->rs_buf, 0, KEYSZ + IVSZ);
	rs->rs_have = sizeof(rsx->rs_buf) - KEYSZ - IVSZ;
}

static inline void
_rs_random_buf(void *_buf, size_t n)
{
	u_char *buf = (u_char *)_buf;
	u_char *keystream;
	size_t m;

	_rs_stir_if_needed(n);
	while (n > 0) {
		if (rs->rs_have > 0) {
			m = minimum(n, rs->rs_have);
			keystream = rsx->rs_buf + sizeof(rsx->rs_buf)
			    - rs->rs_have;
			memcpy(buf, keystream, m);
			memset(keystream, 0, m);
			buf += m;
			n -= m;
			rs->rs_have -= m;
		}
		if (rs->rs_have == 0)
			_rs_rekey(NULL, 0);
	}
}

static inline void
_rs_random_u32(uint32_t *val)
{
	u_char *keystream;

	_rs_stir_if_needed(sizeof(*val));
	if (rs->rs_have < sizeof(*val))
		_rs_rekey(NULL, 0);
	keystream = rsx->rs_buf + sizeof(rsx->rs_buf) - rs->rs_have;
	memcpy(val, keystream, sizeof(*val));
	memset(keystream, 0, sizeof(*val));
	rs->rs_have -= sizeof(*val);
}

uint32_t
arc4random(void)
{
	uint32_t val;

	_ARC4_LOCK();
	_rs_random_u32(&val);
	_ARC4_UNLOCK();
	return val;
}
DEF_WEAK(arc4random);

void
arc4random_buf(void *buf, size_t n)
{
	_ARC4_LOCK();
	_rs_random_buf(buf, n);
	_ARC4_UNLOCK();
}
DEF_WEAK(arc4random_buf);


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: arc4random.c,v 1.54 2015/09/13 08:31:47 guenther Exp $ */
2
3			/*
4			* Copyright (c) 1996, David Mazieres <dm@uun.org>
5			* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
6			* Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
7			* Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org>
8			*
9			* Permission to use, copy, modify, and distribute this software for any
10			* purpose with or without fee is hereby granted, provided that the above
11			* copyright notice and this permission notice appear in all copies.
12			*
13			* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
14			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
15			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
16			* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
17			* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
18			* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
19			* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
20			*/
21
22			/*
23			* ChaCha based random number generator for OpenBSD.
24			*/
25
26			#include <fcntl.h>
27			#include <limits.h>
28			#include <signal.h>
29			#include <stdint.h>
30			#include <stdlib.h>
31			#include <string.h>
32			#include <unistd.h>
33			#include <sys/types.h>
34			#include <sys/time.h>
35
36			#define KEYSTREAM_ONLY
37			#include "chacha_private.h"
38
39			#define minimum(a, b) ((a) < (b) ? (a) : (b))
40
41			#if defined(__GNUC__) \|\| defined(_MSC_VER)
42			#define inline __inline
43			#else /* __GNUC__ \|\| _MSC_VER */
44			#define inline
45			#endif /* !__GNUC__ && !_MSC_VER */
46
47			#define KEYSZ 32
48			#define IVSZ 8
49			#define BLOCKSZ 64
50			#define RSBUFSZ (16*BLOCKSZ)
51
52			/* Marked MAP_INHERIT_ZERO, so zero'd out in fork children. */
53			static struct _rs {
54			size_t rs_have; /* valid bytes at end of rs_buf */
55			size_t rs_count; /* bytes till reseed */
56			} *rs;
57
58			/* Maybe be preserved in fork children, if _rs_allocate() decides. */
59			static struct _rsx {
60			chacha_ctx rs_chacha; /* chacha context for random keystream */
61			u_char rs_buf[RSBUFSZ]; /* keystream blocks */
62			} *rsx;
63
64			static inline int _rs_allocate(struct _rs , struct _rsx );
65			static inline void _rs_forkdetect(void);
66			#include "arc4random.h"
67
68			static inline void _rs_rekey(u_char *dat, size_t datlen);
69
70			static inline void
71			_rs_init(u_char *buf, size_t n)
72			{
73	✓✗	1395048	if (n < KEYSZ + IVSZ)
74			return;
75
76	✓✓	697524	if (rs == NULL) {
77	✗✓	74681	if (_rs_allocate(&rs, &rsx) == -1)
78			abort();
79			}
80
81		697524	chacha_keysetup(&rsx->rs_chacha, buf, KEYSZ * 8, 0);
82		697524	chacha_ivsetup(&rsx->rs_chacha, buf + KEYSZ);
83		1395048	}
84
85			static void
86			_rs_stir(void)
87			{
88		191978	u_char rnd[KEYSZ + IVSZ];
89
90	✗✓	95989	if (getentropy(rnd, sizeof rnd) == -1)
91			_getentropy_fail();
92
93	✓✓	95989	if (!rs)
94		74681	_rs_init(rnd, sizeof(rnd));
95			else
96		21308	_rs_rekey(rnd, sizeof(rnd));
97		95989	explicit_bzero(rnd, sizeof(rnd)); /* discard source seed */
98
99			/* invalidate rs_buf */
100		95989	rs->rs_have = 0;
101		95989	memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
102
103		95989	rs->rs_count = 1600000;
104		95989	}
105
106			static inline void
107			_rs_stir_if_needed(size_t len)
108			{
109		37385864	_rs_forkdetect();
110	✓✓✓✓	37311183	if (!rs \|\| rs->rs_count <= len)
111		95989	_rs_stir();
112	✗✓	18692932	if (rs->rs_count <= len)
113			rs->rs_count = 0;
114			else
115		18692932	rs->rs_count -= len;
116		18692932	}
117
118			static inline void
119			_rs_rekey(u_char *dat, size_t datlen)
120			{
121			#ifndef KEYSTREAM_ONLY
122			memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
123			#endif
124			/* fill rs_buf with the keystream */
125		1244388	chacha_encrypt_bytes(&rsx->rs_chacha, rsx->rs_buf,
126			rsx->rs_buf, sizeof(rsx->rs_buf));
127			/* mix in optional user provided data */
128	✓✓	622194	if (dat) {
129			size_t i, m;
130
131		21308	m = minimum(datlen, KEYSZ + IVSZ);
132	✓✓	1747256	for (i = 0; i < m; i++)
133		852320	rsx->rs_buf[i] ^= dat[i];
134		21308	}
135			/* immediately reinit for backtracking resistance */
136		622194	_rs_init(rsx->rs_buf, KEYSZ + IVSZ);
137		622194	memset(rsx->rs_buf, 0, KEYSZ + IVSZ);
138		622194	rs->rs_have = sizeof(rsx->rs_buf) - KEYSZ - IVSZ;
139		622194	}
140
141			static inline void
142			_rs_random_buf(void *_buf, size_t n)
143			{
144			u_char buf = (u_char )_buf;
145			u_char *keystream;
146			size_t m;
147
148		33779978	_rs_stir_if_needed(n);
149	✓✓	51125053	while (n > 0) {
150	✓✓	17345075	if (rs->rs_have > 0) {
151	✓✓	51962517	m = minimum(n, rs->rs_have);
152		17320839	keystream = rsx->rs_buf + sizeof(rsx->rs_buf)
153		17320839	- rs->rs_have;
154		17320839	memcpy(buf, keystream, m);
155		17320839	memset(keystream, 0, m);
156		17320839	buf += m;
157		17320839	n -= m;
158		17320839	rs->rs_have -= m;
159		17320839	}
160	✓✓	17345075	if (rs->rs_have == 0)
161		521476	_rs_rekey(NULL, 0);
162			}
163		16889989	}
164
165			static inline void
166			_rs_random_u32(uint32_t *val)
167			{
168			u_char *keystream;
169
170		3585098	_rs_stir_if_needed(sizeof(*val));
171	✓✓	1792549	if (rs->rs_have < sizeof(*val))
172		79082	_rs_rekey(NULL, 0);
173		1792549	keystream = rsx->rs_buf + sizeof(rsx->rs_buf) - rs->rs_have;
174		1792549	memcpy(val, keystream, sizeof(*val));
175		1792549	memset(keystream, 0, sizeof(*val));
176		1792549	rs->rs_have -= sizeof(*val);
177		1792549	}
178
179			uint32_t
180			arc4random(void)
181			{
182		3585098	uint32_t val;
183
184	✗✓	1792549	_ARC4_LOCK();
185		1792549	_rs_random_u32(&val);
186	✗✓	1792549	_ARC4_UNLOCK();
187		3585098	return val;
188		1792549	}
189			DEF_WEAK(arc4random);
190
191			void
192			arc4random_buf(void *buf, size_t n)
193			{
194	✗✓	33758972	_ARC4_LOCK();
195		16879486	_rs_random_buf(buf, n);
196	✗✓	16879486	_ARC4_UNLOCK();
197		16879486	}
198			DEF_WEAK(arc4random_buf);