rand_unix.c@ 91108

Last change on this file since 91108 was 90293, checked in by vboxsync, 4 years ago
openssl-1.1.1k: Applied and adjusted our OpenSSL changes to 1.1.1k. bugref:10072
File size: 25.4 KB

Line
1	/*
2	* Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
3	*
4	* Licensed under the OpenSSL license (the "License"). You may not use
5	* this file except in compliance with the License. You can obtain a copy
6	* in the file LICENSE in the source distribution or at
7	* https://www.openssl.org/source/license.html
8	*/
9
10	#ifndef _GNU_SOURCE
11	# define _GNU_SOURCE
12	#endif
13	#include "e_os.h"
14	#include <stdio.h>
15	#include "internal/cryptlib.h"
16	#include <openssl/rand.h>
17	#include <openssl/crypto.h>
18	#include "rand_local.h"
19	#include "crypto/rand.h"
20	#include <stdio.h>
21	#include "internal/dso.h"
22	#ifdef __linux
23	# include <sys/syscall.h>
24	# ifdef DEVRANDOM_WAIT
25	# include <sys/shm.h>
26	# include <sys/utsname.h>
27	# endif
28	#endif
29	#if (defined(__FreeBSD__) \|\| defined(__NetBSD__)) && !defined(OPENSSL_SYS_UEFI)
30	# include <sys/types.h>
31	# include <sys/sysctl.h>
32	# include <sys/param.h>
33	#endif
34	#if defined(__OpenBSD__)
35	# include <sys/param.h>
36	#endif
37
38	#if defined(OPENSSL_SYS_UNIX) \|\| defined(__DJGPP__)
39	# include <sys/types.h>
40	# include <sys/stat.h>
41	# include <fcntl.h>
42	# include <unistd.h>
43	# include <sys/time.h>
44
45	static uint64_t get_time_stamp(void);
46	static uint64_t get_timer_bits(void);
47
48	/* Macro to convert two thirty two bit values into a sixty four bit one */
49	# define TWO32TO64(a, b) ((((uint64_t)(a)) << 32) + (b))
50
51	/*
52	* Check for the existence and support of POSIX timers. The standard
53	* says that the _POSIX_TIMERS macro will have a positive value if they
54	* are available.
55	*
56	* However, we want an additional constraint: that the timer support does
57	* not require an extra library dependency. Early versions of glibc
58	* require -lrt to be specified on the link line to access the timers,
59	* so this needs to be checked for.
60	*
61	* It is worse because some libraries define __GLIBC__ but don't
62	* support the version testing macro (e.g. uClibc). This means
63	* an extra check is needed.
64	*
65	* The final condition is:
66	* "have posix timers and either not glibc or glibc without -lrt"
67	*
68	* The nested #if sequences are required to avoid using a parameterised
69	* macro that might be undefined.
70	*/
71	# undef OSSL_POSIX_TIMER_OKAY
72	# if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
73	# if defined(__GLIBC__)
74	# if defined(__GLIBC_PREREQ)
75	# if __GLIBC_PREREQ(2, 17)
76	# define OSSL_POSIX_TIMER_OKAY
77	# endif
78	# endif
79	# else
80	# define OSSL_POSIX_TIMER_OKAY
81	# endif
82	# endif
83	#endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS))
84	\|\| defined(__DJGPP__) */
85
86	#if defined(OPENSSL_RAND_SEED_NONE)
87	/* none means none. this simplifies the following logic */
88	# undef OPENSSL_RAND_SEED_OS
89	# undef OPENSSL_RAND_SEED_GETRANDOM
90	# undef OPENSSL_RAND_SEED_LIBRANDOM
91	# undef OPENSSL_RAND_SEED_DEVRANDOM
92	# undef OPENSSL_RAND_SEED_RDTSC
93	# undef OPENSSL_RAND_SEED_RDCPU
94	# undef OPENSSL_RAND_SEED_EGD
95	#endif
96
97	#if (defined(OPENSSL_SYS_VXWORKS) \|\| defined(OPENSSL_SYS_UEFI)) && \
98	!defined(OPENSSL_RAND_SEED_NONE)
99	# error "UEFI and VXWorks only support seeding NONE"
100	#endif
101
102	#if defined(OPENSSL_SYS_VXWORKS)
103	/* empty implementation */
104	int rand_pool_init(void)
105	{
106	return 1;
107	}
108
109	void rand_pool_cleanup(void)
110	{
111	}
112
113	void rand_pool_keep_random_devices_open(int keep)
114	{
115	}
116
117	size_t rand_pool_acquire_entropy(RAND_POOL *pool)
118	{
119	return rand_pool_entropy_available(pool);
120	}
121	#endif
122
123	#if !(defined(OPENSSL_SYS_WINDOWS) \|\| defined(OPENSSL_SYS_WIN32) \
124	\|\| defined(OPENSSL_SYS_VMS) \|\| defined(OPENSSL_SYS_VXWORKS) \
125	\|\| defined(OPENSSL_SYS_UEFI))
126
127	# if defined(OPENSSL_SYS_VOS)
128
129	# ifndef OPENSSL_RAND_SEED_OS
130	# error "Unsupported seeding method configured; must be os"
131	# endif
132
133	# if defined(OPENSSL_SYS_VOS_HPPA) && defined(OPENSSL_SYS_VOS_IA32)
134	# error "Unsupported HP-PA and IA32 at the same time."
135	# endif
136	# if !defined(OPENSSL_SYS_VOS_HPPA) && !defined(OPENSSL_SYS_VOS_IA32)
137	# error "Must have one of HP-PA or IA32"
138	# endif
139
140	/*
141	* The following algorithm repeatedly samples the real-time clock (RTC) to
142	* generate a sequence of unpredictable data. The algorithm relies upon the
143	* uneven execution speed of the code (due to factors such as cache misses,
144	* interrupts, bus activity, and scheduling) and upon the rather large
145	* relative difference between the speed of the clock and the rate at which
146	* it can be read. If it is ported to an environment where execution speed
147	* is more constant or where the RTC ticks at a much slower rate, or the
148	* clock can be read with fewer instructions, it is likely that the results
149	* would be far more predictable. This should only be used for legacy
150	* platforms.
151	*
152	* As a precaution, we assume only 2 bits of entropy per byte.
153	*/
154	size_t rand_pool_acquire_entropy(RAND_POOL *pool)
155	{
156	short int code;
157	int i, k;
158	size_t bytes_needed;
159	struct timespec ts;
160	unsigned char v;
161	# ifdef OPENSSL_SYS_VOS_HPPA
162	long duration;
163	extern void s$sleep(long _duration, short int _code);
164	# else
165	long long duration;
166	extern void s$sleep2(long long _duration, short int _code);
167	# endif
168
169	bytes_needed = rand_pool_bytes_needed(pool, 4 /entropy_factor/);
170
171	for (i = 0; i < bytes_needed; i++) {
172	/*
173	* burn some cpu; hope for interrupts, cache collisions, bus
174	* interference, etc.
175	*/
176	for (k = 0; k < 99; k++)
177	ts.tv_nsec = random();
178
179	# ifdef OPENSSL_SYS_VOS_HPPA
180	/* sleep for 1/1024 of a second (976 us). */
181	duration = 1;
182	s$sleep(&duration, &code);
183	# else
184	/* sleep for 1/65536 of a second (15 us). */
185	duration = 1;
186	s$sleep2(&duration, &code);
187	# endif
188
189	/* Get wall clock time, take 8 bits. */
190	clock_gettime(CLOCK_REALTIME, &ts);
191	v = (unsigned char)(ts.tv_nsec & 0xFF);
192	rand_pool_add(pool, arg, &v, sizeof(v) , 2);
193	}
194	return rand_pool_entropy_available(pool);
195	}
196
197	void rand_pool_cleanup(void)
198	{
199	}
200
201	void rand_pool_keep_random_devices_open(int keep)
202	{
203	}
204
205	# else
206
207	# if defined(OPENSSL_RAND_SEED_EGD) && \
208	(defined(OPENSSL_NO_EGD) \|\| !defined(DEVRANDOM_EGD))
209	# error "Seeding uses EGD but EGD is turned off or no device given"
210	# endif
211
212	# if defined(OPENSSL_RAND_SEED_DEVRANDOM) && !defined(DEVRANDOM)
213	# error "Seeding uses urandom but DEVRANDOM is not configured"
214	# endif
215
216	# if defined(OPENSSL_RAND_SEED_OS)
217	# if !defined(DEVRANDOM)
218	# error "OS seeding requires DEVRANDOM to be configured"
219	# endif
220	# define OPENSSL_RAND_SEED_GETRANDOM
221	# define OPENSSL_RAND_SEED_DEVRANDOM
222	# endif
223
224	# if defined(OPENSSL_RAND_SEED_LIBRANDOM)
225	# error "librandom not (yet) supported"
226	# endif
227
228	# if (defined(__FreeBSD__) \|\| defined(__NetBSD__)) && defined(KERN_ARND)
229	/*
230	* sysctl_random(): Use sysctl() to read a random number from the kernel
231	* Returns the number of bytes returned in buf on success, -1 on failure.
232	*/
233	static ssize_t sysctl_random(char *buf, size_t buflen)
234	{
235	int mib[2];
236	size_t done = 0;
237	size_t len;
238
239	/*
240	* Note: sign conversion between size_t and ssize_t is safe even
241	* without a range check, see comment in syscall_random()
242	*/
243
244	/*
245	* On FreeBSD old implementations returned longs, newer versions support
246	* variable sizes up to 256 byte. The code below would not work properly
247	* when the sysctl returns long and we want to request something not a
248	* multiple of longs, which should never be the case.
249	*/
250	#if defined(__FreeBSD__)
251	if (!ossl_assert(buflen % sizeof(long) == 0)) {
252	errno = EINVAL;
253	return -1;
254	}
255	#endif
256
257	/*
258	* On NetBSD before 4.0 KERN_ARND was an alias for KERN_URND, and only
259	* filled in an int, leaving the rest uninitialized. Since NetBSD 4.0
260	* it returns a variable number of bytes with the current version supporting
261	* up to 256 bytes.
262	* Just return an error on older NetBSD versions.
263	*/
264	#if defined(__NetBSD__) && __NetBSD_Version__ < 400000000
265	errno = ENOSYS;
266	return -1;
267	#endif
268
269	mib[0] = CTL_KERN;
270	mib[1] = KERN_ARND;
271
272	do {
273	len = buflen > 256 ? 256 : buflen;
274	if (sysctl(mib, 2, buf, &len, NULL, 0) == -1)
275	return done > 0 ? done : -1;
276	done += len;
277	buf += len;
278	buflen -= len;
279	} while (buflen > 0);
280
281	return done;
282	}
283	# endif
284
285	# if defined(OPENSSL_RAND_SEED_GETRANDOM)
286
287	# if defined(__linux) && !defined(__NR_getrandom)
288	# if defined(__arm__)
289	# define __NR_getrandom (__NR_SYSCALL_BASE+384)
290	# elif defined(__i386__)
291	# define __NR_getrandom 355
292	# elif defined(__x86_64__)
293	# if defined(__ILP32__)
294	# define __NR_getrandom (__X32_SYSCALL_BIT + 318)
295	# else
296	# define __NR_getrandom 318
297	# endif
298	# elif defined(__xtensa__)
299	# define __NR_getrandom 338
300	# elif defined(__s390__) \|\| defined(__s390x__)
301	# define __NR_getrandom 349
302	# elif defined(__bfin__)
303	# define __NR_getrandom 389
304	# elif defined(__powerpc__)
305	# define __NR_getrandom 359
306	# elif defined(__mips__) \|\| defined(__mips64)
307	# if _MIPS_SIM == _MIPS_SIM_ABI32
308	# define __NR_getrandom (__NR_Linux + 353)
309	# elif _MIPS_SIM == _MIPS_SIM_ABI64
310	# define __NR_getrandom (__NR_Linux + 313)
311	# elif _MIPS_SIM == _MIPS_SIM_NABI32
312	# define __NR_getrandom (__NR_Linux + 317)
313	# endif
314	# elif defined(__hppa__)
315	# define __NR_getrandom (__NR_Linux + 339)
316	# elif defined(__sparc__)
317	# define __NR_getrandom 347
318	# elif defined(__ia64__)
319	# define __NR_getrandom 1339
320	# elif defined(__alpha__)
321	# define __NR_getrandom 511
322	# elif defined(__sh__)
323	# if defined(__SH5__)
324	# define __NR_getrandom 373
325	# else
326	# define __NR_getrandom 384
327	# endif
328	# elif defined(__avr32__)
329	# define __NR_getrandom 317
330	# elif defined(__microblaze__)
331	# define __NR_getrandom 385
332	# elif defined(__m68k__)
333	# define __NR_getrandom 352
334	# elif defined(__cris__)
335	# define __NR_getrandom 356
336	# elif defined(__aarch64__)
337	# define __NR_getrandom 278
338	# else /* generic */
339	# define __NR_getrandom 278
340	# endif
341	# endif
342
343	/*
344	* syscall_random(): Try to get random data using a system call
345	* returns the number of bytes returned in buf, or < 0 on error.
346	*/
347	static ssize_t syscall_random(void *buf, size_t buflen)
348	{
349	/*
350	* Note: 'buflen' equals the size of the buffer which is used by the
351	* get_entropy() callback of the RAND_DRBG. It is roughly bounded by
352	*
353	* 2 * RAND_POOL_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^14
354	*
355	* which is way below the OSSL_SSIZE_MAX limit. Therefore sign conversion
356	* between size_t and ssize_t is safe even without a range check.
357	*/
358
359	/*
360	* Do runtime detection to find getentropy().
361	*
362	* Known OSs that should support this:
363	* - Darwin since 16 (OSX 10.12, IOS 10.0).
364	* - Solaris since 11.3
365	* - OpenBSD since 5.6
366	* - Linux since 3.17 with glibc 2.25
367	* - FreeBSD since 12.0 (1200061)
368	*
369	* Note: Sometimes getentropy() can be provided but not implemented
370	* internally. So we need to check errno for ENOSYS
371	*/
372	# if defined(__GNUC__) && __GNUC__>=2 && defined(__ELF__) && !defined(__hpux)
373	extern int getentropy(void *buffer, size_t length) __attribute__((weak));
374
375	if (getentropy != NULL) {
376	if (getentropy(buf, buflen) == 0)
377	return (ssize_t)buflen;
378	if (errno != ENOSYS)
379	return -1;
380	}
381	# else
382	union {
383	void *p;
384	int (f)(void buffer, size_t length);
385	} p_getentropy;
386
387	/*
388	* We could cache the result of the lookup, but we normally don't
389	* call this function often.
390	*/
391	ERR_set_mark();
392	p_getentropy.p = DSO_global_lookup("getentropy");
393	ERR_pop_to_mark();
394	if (p_getentropy.p != NULL)
395	return p_getentropy.f(buf, buflen) == 0 ? (ssize_t)buflen : -1;
396	# endif
397
398	/* Linux supports this since version 3.17 */
399	# if defined(__linux) && defined(__NR_getrandom)
400	return syscall(__NR_getrandom, buf, buflen, 0);
401	# elif (defined(__FreeBSD__) \|\| defined(__NetBSD__)) && defined(KERN_ARND)
402	return sysctl_random(buf, buflen);
403	# else
404	errno = ENOSYS;
405	return -1;
406	# endif
407	}
408	# endif /* defined(OPENSSL_RAND_SEED_GETRANDOM) */
409
410	# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
411	static const char *random_device_paths[] = { DEVRANDOM };
412	static struct random_device {
413	int fd;
414	dev_t dev;
415	ino_t ino;
416	mode_t mode;
417	dev_t rdev;
418	} random_devices[OSSL_NELEM(random_device_paths)];
419	static int keep_random_devices_open = 1;
420
421	# if defined(__linux) && defined(DEVRANDOM_WAIT) \
422	&& defined(OPENSSL_RAND_SEED_GETRANDOM)
423	static void *shm_addr;
424
425	static void cleanup_shm(void)
426	{
427	shmdt(shm_addr);
428	}
429
430	/*
431	* Ensure that the system randomness source has been adequately seeded.
432	* This is done by having the first start of libcrypto, wait until the device
433	* /dev/random becomes able to supply a byte of entropy. Subsequent starts
434	* of the library and later reseedings do not need to do this.
435	*/
436	static int wait_random_seeded(void)
437	{
438	static int seeded = OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID < 0;
439	static const int kernel_version[] = { DEVRANDOM_SAFE_KERNEL };
440	int kernel[2];
441	int shm_id, fd, r;
442	char c, *p;
443	struct utsname un;
444	fd_set fds;
445
446	if (!seeded) {
447	/* See if anything has created the global seeded indication */
448	if ((shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1, 0)) == -1) {
449	/*
450	* Check the kernel's version and fail if it is too recent.
451	*
452	* Linux kernels from 4.8 onwards do not guarantee that
453	* /dev/urandom is properly seeded when /dev/random becomes
454	* readable. However, such kernels support the getentropy(2)
455	* system call and this should always succeed which renders
456	* this alternative but essentially identical source moot.
457	*/
458	if (uname(&un) == 0) {
459	kernel[0] = atoi(un.release);
460	p = strchr(un.release, '.');
461	kernel[1] = p == NULL ? 0 : atoi(p + 1);
462	if (kernel[0] > kernel_version[0]
463	\|\| (kernel[0] == kernel_version[0]
464	&& kernel[1] >= kernel_version[1])) {
465	return 0;
466	}
467	}
468	/* Open /dev/random and wait for it to be readable */
469	if ((fd = open(DEVRANDOM_WAIT, O_RDONLY)) != -1) {
470	if (DEVRANDM_WAIT_USE_SELECT && fd < FD_SETSIZE) {
471	FD_ZERO(&fds);
472	FD_SET(fd, &fds);
473	while ((r = select(fd + 1, &fds, NULL, NULL, NULL)) < 0
474	&& errno == EINTR);
475	} else {
476	while ((r = read(fd, &c, 1)) < 0 && errno == EINTR);
477	}
478	close(fd);
479	if (r == 1) {
480	seeded = 1;
481	/* Create the shared memory indicator */
482	shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1,
483	IPC_CREAT \| S_IRUSR \| S_IRGRP \| S_IROTH);
484	}
485	}
486	}
487	if (shm_id != -1) {
488	seeded = 1;
489	/*
490	* Map the shared memory to prevent its premature destruction.
491	* If this call fails, it isn't a big problem.
492	*/
493	shm_addr = shmat(shm_id, NULL, SHM_RDONLY);
494	if (shm_addr != (void *)-1)
495	OPENSSL_atexit(&cleanup_shm);
496	}
497	}
498	return seeded;
499	}
500	# else /* defined __linux && DEVRANDOM_WAIT && OPENSSL_RAND_SEED_GETRANDOM */
501	static int wait_random_seeded(void)
502	{
503	return 1;
504	}
505	# endif
506
507	/*
508	* Verify that the file descriptor associated with the random source is
509	* still valid. The rationale for doing this is the fact that it is not
510	* uncommon for daemons to close all open file handles when daemonizing.
511	* So the handle might have been closed or even reused for opening
512	* another file.
513	*/
514	static int check_random_device(struct random_device * rd)
515	{
516	struct stat st;
517
518	return rd->fd != -1
519	&& fstat(rd->fd, &st) != -1
520	&& rd->dev == st.st_dev
521	&& rd->ino == st.st_ino
522	&& ((rd->mode ^ st.st_mode) & ~(S_IRWXU \| S_IRWXG \| S_IRWXO)) == 0
523	&& rd->rdev == st.st_rdev;
524	}
525
526	/*
527	* Open a random device if required and return its file descriptor or -1 on error
528	*/
529	static int get_random_device(size_t n)
530	{
531	struct stat st;
532	struct random_device * rd = &random_devices[n];
533
534	/* reuse existing file descriptor if it is (still) valid */
535	if (check_random_device(rd))
536	return rd->fd;
537
538	/* open the random device ... */
539	if ((rd->fd = open(random_device_paths[n], O_RDONLY)) == -1)
540	return rd->fd;
541
542	/* ... and cache its relevant stat(2) data */
543	if (fstat(rd->fd, &st) != -1) {
544	rd->dev = st.st_dev;
545	rd->ino = st.st_ino;
546	rd->mode = st.st_mode;
547	rd->rdev = st.st_rdev;
548	} else {
549	close(rd->fd);
550	rd->fd = -1;
551	}
552
553	return rd->fd;
554	}
555
556	/*
557	* Close a random device making sure it is a random device
558	*/
559	static void close_random_device(size_t n)
560	{
561	struct random_device * rd = &random_devices[n];
562
563	if (check_random_device(rd))
564	close(rd->fd);
565	rd->fd = -1;
566	}
567
568	int rand_pool_init(void)
569	{
570	size_t i;
571
572	for (i = 0; i < OSSL_NELEM(random_devices); i++)
573	random_devices[i].fd = -1;
574
575	return 1;
576	}
577
578	void rand_pool_cleanup(void)
579	{
580	size_t i;
581
582	for (i = 0; i < OSSL_NELEM(random_devices); i++)
583	close_random_device(i);
584	}
585
586	void rand_pool_keep_random_devices_open(int keep)
587	{
588	if (!keep)
589	rand_pool_cleanup();
590
591	keep_random_devices_open = keep;
592	}
593
594	# else /* !defined(OPENSSL_RAND_SEED_DEVRANDOM) */
595
596	int rand_pool_init(void)
597	{
598	return 1;
599	}
600
601	void rand_pool_cleanup(void)
602	{
603	}
604
605	void rand_pool_keep_random_devices_open(int keep)
606	{
607	}
608
609	# endif /* defined(OPENSSL_RAND_SEED_DEVRANDOM) */
610
611	/*
612	* Try the various seeding methods in turn, exit when successful.
613	*
614	* TODO(DRBG): If more than one entropy source is available, is it
615	* preferable to stop as soon as enough entropy has been collected
616	* (as favored by @rsalz) or should one rather be defensive and add
617	* more entropy than requested and/or from different sources?
618	*
619	* Currently, the user can select multiple entropy sources in the
620	* configure step, yet in practice only the first available source
621	* will be used. A more flexible solution has been requested, but
622	* currently it is not clear how this can be achieved without
623	* overengineering the problem. There are many parameters which
624	* could be taken into account when selecting the order and amount
625	* of input from the different entropy sources (trust, quality,
626	* possibility of blocking).
627	*/
628	size_t rand_pool_acquire_entropy(RAND_POOL *pool)
629	{
630	# if defined(OPENSSL_RAND_SEED_NONE)
631	return rand_pool_entropy_available(pool);
632	# else
633	size_t entropy_available;
634
635	# if defined(OPENSSL_RAND_SEED_GETRANDOM)
636	{
637	size_t bytes_needed;
638	unsigned char *buffer;
639	ssize_t bytes;
640	/* Maximum allowed number of consecutive unsuccessful attempts */
641	int attempts = 3;
642
643	bytes_needed = rand_pool_bytes_needed(pool, 1 /entropy_factor/);
644	while (bytes_needed != 0 && attempts-- > 0) {
645	buffer = rand_pool_add_begin(pool, bytes_needed);
646	bytes = syscall_random(buffer, bytes_needed);
647	if (bytes > 0) {
648	rand_pool_add_end(pool, bytes, 8 * bytes);
649	bytes_needed -= bytes;
650	attempts = 3; /* reset counter after successful attempt */
651	} else if (bytes < 0 && errno != EINTR) {
652	break;
653	}
654	}
655	}
656	entropy_available = rand_pool_entropy_available(pool);
657	if (entropy_available > 0)
658	return entropy_available;
659	# endif
660
661	# if defined(OPENSSL_RAND_SEED_LIBRANDOM)
662	{
663	/* Not yet implemented. */
664	}
665	# endif
666
667	# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
668	if (wait_random_seeded()) {
669	size_t bytes_needed;
670	unsigned char *buffer;
671	size_t i;
672
673	bytes_needed = rand_pool_bytes_needed(pool, 1 /entropy_factor/);
674	for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths);
675	i++) {
676	ssize_t bytes = 0;
677	/* Maximum number of consecutive unsuccessful attempts */
678	int attempts = 3;
679	const int fd = get_random_device(i);
680
681	if (fd == -1)
682	continue;
683
684	while (bytes_needed != 0 && attempts-- > 0) {
685	buffer = rand_pool_add_begin(pool, bytes_needed);
686	bytes = read(fd, buffer, bytes_needed);
687
688	if (bytes > 0) {
689	rand_pool_add_end(pool, bytes, 8 * bytes);
690	bytes_needed -= bytes;
691	attempts = 3; /* reset counter on successful attempt */
692	} else if (bytes < 0 && errno != EINTR) {
693	break;
694	}
695	}
696	if (bytes < 0 \|\| !keep_random_devices_open)
697	close_random_device(i);
698
699	bytes_needed = rand_pool_bytes_needed(pool, 1);
700	}
701	entropy_available = rand_pool_entropy_available(pool);
702	if (entropy_available > 0)
703	return entropy_available;
704	}
705	# endif
706
707	# if defined(OPENSSL_RAND_SEED_RDTSC)
708	entropy_available = rand_acquire_entropy_from_tsc(pool);
709	if (entropy_available > 0)
710	return entropy_available;
711	# endif
712
713	# if defined(OPENSSL_RAND_SEED_RDCPU)
714	entropy_available = rand_acquire_entropy_from_cpu(pool);
715	if (entropy_available > 0)
716	return entropy_available;
717	# endif
718
719	# if defined(OPENSSL_RAND_SEED_EGD)
720	{
721	static const char *paths[] = { DEVRANDOM_EGD, NULL };
722	size_t bytes_needed;
723	unsigned char *buffer;
724	int i;
725
726	bytes_needed = rand_pool_bytes_needed(pool, 1 /entropy_factor/);
727	for (i = 0; bytes_needed > 0 && paths[i] != NULL; i++) {
728	size_t bytes = 0;
729	int num;
730
731	buffer = rand_pool_add_begin(pool, bytes_needed);
732	num = RAND_query_egd_bytes(paths[i],
733	buffer, (int)bytes_needed);
734	if (num == (int)bytes_needed)
735	bytes = bytes_needed;
736
737	rand_pool_add_end(pool, bytes, 8 * bytes);
738	bytes_needed = rand_pool_bytes_needed(pool, 1);
739	}
740	entropy_available = rand_pool_entropy_available(pool);
741	if (entropy_available > 0)
742	return entropy_available;
743	}
744	# endif
745
746	return rand_pool_entropy_available(pool);
747	# endif
748	}
749	# endif
750	#endif
751
752	#if defined(OPENSSL_SYS_UNIX) \|\| defined(__DJGPP__)
753	int rand_pool_add_nonce_data(RAND_POOL *pool)
754	{
755	struct {
756	pid_t pid;
757	CRYPTO_THREAD_ID tid;
758	uint64_t time;
759	} data = { 0 };
760
761	/*
762	* Add process id, thread id, and a high resolution timestamp to
763	* ensure that the nonce is unique with high probability for
764	* different process instances.
765	*/
766	data.pid = getpid();
767	data.tid = CRYPTO_THREAD_get_current_id();
768	data.time = get_time_stamp();
769
770	return rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
771	}
772
773	int rand_pool_add_additional_data(RAND_POOL *pool)
774	{
775	struct {
776	int fork_id;
777	CRYPTO_THREAD_ID tid;
778	uint64_t time;
779	} data = { 0 };
780
781	/*
782	* Add some noise from the thread id and a high resolution timer.
783	* The fork_id adds some extra fork-safety.
784	* The thread id adds a little randomness if the drbg is accessed
785	* concurrently (which is the case for the <master> drbg).
786	*/
787	data.fork_id = openssl_get_fork_id();
788	data.tid = CRYPTO_THREAD_get_current_id();
789	data.time = get_timer_bits();
790
791	return rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
792	}
793
794
795	/*
796	* Get the current time with the highest possible resolution
797	*
798	* The time stamp is added to the nonce, so it is optimized for not repeating.
799	* The current time is ideal for this purpose, provided the computer's clock
800	* is synchronized.
801	*/
802	static uint64_t get_time_stamp(void)
803	{
804	# if defined(OSSL_POSIX_TIMER_OKAY)
805	{
806	struct timespec ts;
807
808	if (clock_gettime(CLOCK_REALTIME, &ts) == 0)
809	return TWO32TO64(ts.tv_sec, ts.tv_nsec);
810	}
811	# endif
812	# if defined(__unix__) \
813	\|\| (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
814	{
815	struct timeval tv;
816
817	if (gettimeofday(&tv, NULL) == 0)
818	return TWO32TO64(tv.tv_sec, tv.tv_usec);
819	}
820	# endif
821	return time(NULL);
822	}
823
824	/*
825	* Get an arbitrary timer value of the highest possible resolution
826	*
827	* The timer value is added as random noise to the additional data,
828	* which is not considered a trusted entropy sourec, so any result
829	* is acceptable.
830	*/
831	static uint64_t get_timer_bits(void)
832	{
833	uint64_t res = OPENSSL_rdtsc();
834
835	if (res != 0)
836	return res;
837
838	# if defined(__sun) \|\| defined(__hpux)
839	return gethrtime();
840	# elif defined(_AIX)
841	{
842	timebasestruct_t t;
843
844	read_wall_time(&t, TIMEBASE_SZ);
845	return TWO32TO64(t.tb_high, t.tb_low);
846	}
847	# elif defined(OSSL_POSIX_TIMER_OKAY)
848	{
849	struct timespec ts;
850
851	# ifdef CLOCK_BOOTTIME
852	# define CLOCK_TYPE CLOCK_BOOTTIME
853	# elif defined(_POSIX_MONOTONIC_CLOCK)
854	# define CLOCK_TYPE CLOCK_MONOTONIC
855	# else
856	# define CLOCK_TYPE CLOCK_REALTIME
857	# endif
858
859	if (clock_gettime(CLOCK_TYPE, &ts) == 0)
860	return TWO32TO64(ts.tv_sec, ts.tv_nsec);
861	}
862	# endif
863	# if defined(__unix__) \
864	\|\| (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
865	{
866	struct timeval tv;
867
868	if (gettimeofday(&tv, NULL) == 0)
869	return TWO32TO64(tv.tv_sec, tv.tv_usec);
870	}
871	# endif
872	return time(NULL);
873	}
874	#endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS))
875	\|\| defined(__DJGPP__) */

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source: vbox/trunk/src/libs/openssl-1.1.1k/crypto/rand/rand_unix.c@ 91108

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