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source: vbox/trunk/src/libs/openssl-3.1.4/providers/implementations/rands/seeding/rand_unix.c@ 102863

Last change on this file since 102863 was 102863, checked in by vboxsync, 15 months ago

openssl-3.1.4: Applied and adjusted our OpenSSL changes to 3.1.3. bugref:10577
File size: 24.3 KB
Line 
1/*
2 * Copyright 1995-2022 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (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 "internal/e_os.h"
14#include <stdio.h>
15#include "internal/cryptlib.h"
16#include <openssl/rand.h>
17#include <openssl/crypto.h>
18#include "crypto/rand_pool.h"
19#include "crypto/rand.h"
20#include "internal/dso.h"
21#include "internal/nelem.h"
22#include "prov/seeding.h"
23
24#ifdef __linux
25# include <sys/syscall.h>
26# ifdef DEVRANDOM_WAIT
27# include <sys/shm.h>
28# include <sys/utsname.h>
29# endif
30#endif
31#if (defined(__FreeBSD__) || defined(__NetBSD__)) && !defined(OPENSSL_SYS_UEFI)
32# include <sys/types.h>
33# include <sys/sysctl.h>
34# include <sys/param.h>
35#endif
36#if defined(__OpenBSD__)
37# include <sys/param.h>
38#endif
39#if defined(__DragonFly__)
40# include <sys/param.h>
41# include <sys/random.h>
42#endif
43
44#if (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS)) \
45 || defined(__DJGPP__)
46# include <sys/types.h>
47# include <sys/stat.h>
48# include <fcntl.h>
49# include <unistd.h>
50# include <sys/time.h>
51
52static uint64_t get_time_stamp(void);
53
54/* Macro to convert two thirty two bit values into a sixty four bit one */
55# define TWO32TO64(a, b) ((((uint64_t)(a)) << 32) + (b))
56
57/*
58 * Check for the existence and support of POSIX timers. The standard
59 * says that the _POSIX_TIMERS macro will have a positive value if they
60 * are available.
61 *
62 * However, we want an additional constraint: that the timer support does
63 * not require an extra library dependency. Early versions of glibc
64 * require -lrt to be specified on the link line to access the timers,
65 * so this needs to be checked for.
66 *
67 * It is worse because some libraries define __GLIBC__ but don't
68 * support the version testing macro (e.g. uClibc). This means
69 * an extra check is needed.
70 *
71 * The final condition is:
72 * "have posix timers and either not glibc or glibc without -lrt"
73 *
74 * The nested #if sequences are required to avoid using a parameterised
75 * macro that might be undefined.
76 */
77# undef OSSL_POSIX_TIMER_OKAY
78/* On some systems, _POSIX_TIMERS is defined but empty.
79 * Subtracting by 0 when comparing avoids an error in this case. */
80# if defined(_POSIX_TIMERS) && _POSIX_TIMERS -0 > 0
81# if defined(__GLIBC__)
82# if defined(__GLIBC_PREREQ)
83# if __GLIBC_PREREQ(2, 17)
84# define OSSL_POSIX_TIMER_OKAY
85# endif
86# endif
87# else
88# define OSSL_POSIX_TIMER_OKAY
89# endif
90# endif
91#endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS))
92 || defined(__DJGPP__) */
93
94#if defined(OPENSSL_RAND_SEED_NONE)
95/* none means none. this simplifies the following logic */
96# undef OPENSSL_RAND_SEED_OS
97# undef OPENSSL_RAND_SEED_GETRANDOM
98# undef OPENSSL_RAND_SEED_LIBRANDOM
99# undef OPENSSL_RAND_SEED_DEVRANDOM
100# undef OPENSSL_RAND_SEED_RDTSC
101# undef OPENSSL_RAND_SEED_RDCPU
102# undef OPENSSL_RAND_SEED_EGD
103#endif
104
105#if defined(OPENSSL_SYS_UEFI) && !defined(OPENSSL_RAND_SEED_NONE)
106# error "UEFI only supports seeding NONE"
107#endif
108
109#if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) \
110 || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) \
111 || defined(OPENSSL_SYS_UEFI))
112
113# if defined(OPENSSL_SYS_VOS)
114
115# ifndef OPENSSL_RAND_SEED_OS
116# error "Unsupported seeding method configured; must be os"
117# endif
118
119# if defined(OPENSSL_SYS_VOS_HPPA) && defined(OPENSSL_SYS_VOS_IA32)
120# error "Unsupported HP-PA and IA32 at the same time."
121# endif
122# if !defined(OPENSSL_SYS_VOS_HPPA) && !defined(OPENSSL_SYS_VOS_IA32)
123# error "Must have one of HP-PA or IA32"
124# endif
125
126/*
127 * The following algorithm repeatedly samples the real-time clock (RTC) to
128 * generate a sequence of unpredictable data. The algorithm relies upon the
129 * uneven execution speed of the code (due to factors such as cache misses,
130 * interrupts, bus activity, and scheduling) and upon the rather large
131 * relative difference between the speed of the clock and the rate at which
132 * it can be read. If it is ported to an environment where execution speed
133 * is more constant or where the RTC ticks at a much slower rate, or the
134 * clock can be read with fewer instructions, it is likely that the results
135 * would be far more predictable. This should only be used for legacy
136 * platforms.
137 *
138 * As a precaution, we assume only 2 bits of entropy per byte.
139 */
140size_t ossl_pool_acquire_entropy(RAND_POOL *pool)
141{
142 short int code;
143 int i, k;
144 size_t bytes_needed;
145 struct timespec ts;
146 unsigned char v;
147# ifdef OPENSSL_SYS_VOS_HPPA
148 long duration;
149 extern void s$sleep(long *_duration, short int *_code);
150# else
151 long long duration;
152 extern void s$sleep2(long long *_duration, short int *_code);
153# endif
154
155 bytes_needed = ossl_rand_pool_bytes_needed(pool, 4 /*entropy_factor*/);
156
157 for (i = 0; i < bytes_needed; i++) {
158 /*
159 * burn some cpu; hope for interrupts, cache collisions, bus
160 * interference, etc.
161 */
162 for (k = 0; k < 99; k++)
163 ts.tv_nsec = random();
164
165# ifdef OPENSSL_SYS_VOS_HPPA
166 /* sleep for 1/1024 of a second (976 us). */
167 duration = 1;
168 s$sleep(&duration, &code);
169# else
170 /* sleep for 1/65536 of a second (15 us). */
171 duration = 1;
172 s$sleep2(&duration, &code);
173# endif
174
175 /* Get wall clock time, take 8 bits. */
176 clock_gettime(CLOCK_REALTIME, &ts);
177 v = (unsigned char)(ts.tv_nsec & 0xFF);
178 ossl_rand_pool_add(pool, arg, &v, sizeof(v) , 2);
179 }
180 return ossl_rand_pool_entropy_available(pool);
181}
182
183void ossl_rand_pool_cleanup(void)
184{
185}
186
187void ossl_rand_pool_keep_random_devices_open(int keep)
188{
189}
190
191# else
192
193# if defined(OPENSSL_RAND_SEED_EGD) && \
194 (defined(OPENSSL_NO_EGD) || !defined(DEVRANDOM_EGD))
195# error "Seeding uses EGD but EGD is turned off or no device given"
196# endif
197
198# if defined(OPENSSL_RAND_SEED_DEVRANDOM) && !defined(DEVRANDOM)
199# error "Seeding uses urandom but DEVRANDOM is not configured"
200# endif
201
202# if defined(OPENSSL_RAND_SEED_OS)
203# if !defined(DEVRANDOM)
204# error "OS seeding requires DEVRANDOM to be configured"
205# endif
206# define OPENSSL_RAND_SEED_GETRANDOM
207# define OPENSSL_RAND_SEED_DEVRANDOM
208# endif
209
210# if defined(OPENSSL_RAND_SEED_LIBRANDOM)
211# error "librandom not (yet) supported"
212# endif
213
214# if (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
215/*
216 * sysctl_random(): Use sysctl() to read a random number from the kernel
217 * Returns the number of bytes returned in buf on success, -1 on failure.
218 */
219static ssize_t sysctl_random(char *buf, size_t buflen)
220{
221 int mib[2];
222 size_t done = 0;
223 size_t len;
224
225 /*
226 * Note: sign conversion between size_t and ssize_t is safe even
227 * without a range check, see comment in syscall_random()
228 */
229
230 /*
231 * On FreeBSD old implementations returned longs, newer versions support
232 * variable sizes up to 256 byte. The code below would not work properly
233 * when the sysctl returns long and we want to request something not a
234 * multiple of longs, which should never be the case.
235 */
236#if defined(__FreeBSD__)
237 if (!ossl_assert(buflen % sizeof(long) == 0)) {
238 errno = EINVAL;
239 return -1;
240 }
241#endif
242
243 /*
244 * On NetBSD before 4.0 KERN_ARND was an alias for KERN_URND, and only
245 * filled in an int, leaving the rest uninitialized. Since NetBSD 4.0
246 * it returns a variable number of bytes with the current version supporting
247 * up to 256 bytes.
248 * Just return an error on older NetBSD versions.
249 */
250#if defined(__NetBSD__) && __NetBSD_Version__ < 400000000
251 errno = ENOSYS;
252 return -1;
253#endif
254
255 mib[0] = CTL_KERN;
256 mib[1] = KERN_ARND;
257
258 do {
259 len = buflen > 256 ? 256 : buflen;
260 if (sysctl(mib, 2, buf, &len, NULL, 0) == -1)
261 return done > 0 ? done : -1;
262 done += len;
263 buf += len;
264 buflen -= len;
265 } while (buflen > 0);
266
267 return done;
268}
269# endif
270
271# if defined(OPENSSL_RAND_SEED_GETRANDOM)
272
273# if defined(__linux) && !defined(__NR_getrandom)
274# if defined(__arm__)
275# define __NR_getrandom (__NR_SYSCALL_BASE+384)
276# elif defined(__i386__)
277# define __NR_getrandom 355
278# elif defined(__x86_64__)
279# if defined(__ILP32__)
280# define __NR_getrandom (__X32_SYSCALL_BIT + 318)
281# else
282# define __NR_getrandom 318
283# endif
284# elif defined(__xtensa__)
285# define __NR_getrandom 338
286# elif defined(__s390__) || defined(__s390x__)
287# define __NR_getrandom 349
288# elif defined(__bfin__)
289# define __NR_getrandom 389
290# elif defined(__powerpc__)
291# define __NR_getrandom 359
292# elif defined(__mips__) || defined(__mips64)
293# if _MIPS_SIM == _MIPS_SIM_ABI32
294# define __NR_getrandom (__NR_Linux + 353)
295# elif _MIPS_SIM == _MIPS_SIM_ABI64
296# define __NR_getrandom (__NR_Linux + 313)
297# elif _MIPS_SIM == _MIPS_SIM_NABI32
298# define __NR_getrandom (__NR_Linux + 317)
299# endif
300# elif defined(__hppa__)
301# define __NR_getrandom (__NR_Linux + 339)
302# elif defined(__sparc__)
303# define __NR_getrandom 347
304# elif defined(__ia64__)
305# define __NR_getrandom 1339
306# elif defined(__alpha__)
307# define __NR_getrandom 511
308# elif defined(__sh__)
309# if defined(__SH5__)
310# define __NR_getrandom 373
311# else
312# define __NR_getrandom 384
313# endif
314# elif defined(__avr32__)
315# define __NR_getrandom 317
316# elif defined(__microblaze__)
317# define __NR_getrandom 385
318# elif defined(__m68k__)
319# define __NR_getrandom 352
320# elif defined(__cris__)
321# define __NR_getrandom 356
322# elif defined(__aarch64__)
323# define __NR_getrandom 278
324# else /* generic */
325# define __NR_getrandom 278
326# endif
327# endif
328
329/*
330 * syscall_random(): Try to get random data using a system call
331 * returns the number of bytes returned in buf, or < 0 on error.
332 */
333static ssize_t syscall_random(void *buf, size_t buflen)
334{
335 /*
336 * Note: 'buflen' equals the size of the buffer which is used by the
337 * get_entropy() callback of the RAND_DRBG. It is roughly bounded by
338 *
339 * 2 * RAND_POOL_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^14
340 *
341 * which is way below the OSSL_SSIZE_MAX limit. Therefore sign conversion
342 * between size_t and ssize_t is safe even without a range check.
343 */
344
345 /*
346 * Do runtime detection to find getentropy().
347 *
348 * Known OSs that should support this:
349 * - Darwin since 16 (OSX 10.12, IOS 10.0).
350 * - Solaris since 11.3
351 * - OpenBSD since 5.6
352 * - Linux since 3.17 with glibc 2.25
353 * - FreeBSD since 12.0 (1200061)
354 *
355 * Note: Sometimes getentropy() can be provided but not implemented
356 * internally. So we need to check errno for ENOSYS
357 */
358# if !defined(__DragonFly__) && !defined(__NetBSD__)
359# if defined(__GNUC__) && __GNUC__>=2 && defined(__ELF__) && !defined(__hpux)
360 extern int getentropy(void *buffer, size_t length) __attribute__((weak));
361
362 if (getentropy != NULL) {
363 if (getentropy(buf, buflen) == 0)
364 return (ssize_t)buflen;
365 if (errno != ENOSYS)
366 return -1;
367 }
368# elif defined(OPENSSL_APPLE_CRYPTO_RANDOM)
369
370 if (CCRandomGenerateBytes(buf, buflen) == kCCSuccess)
371 return (ssize_t)buflen;
372
373 return -1;
374# else
375 union {
376 void *p;
377 int (*f)(void *buffer, size_t length);
378 } p_getentropy;
379
380 /*
381 * We could cache the result of the lookup, but we normally don't
382 * call this function often.
383 */
384 ERR_set_mark();
385 p_getentropy.p = DSO_global_lookup("getentropy");
386 ERR_pop_to_mark();
387 if (p_getentropy.p != NULL)
388 return p_getentropy.f(buf, buflen) == 0 ? (ssize_t)buflen : -1;
389# endif
390# endif /* !__DragonFly__ */
391
392 /* Linux supports this since version 3.17 */
393# if defined(__linux) && defined(__NR_getrandom)
394 return syscall(__NR_getrandom, buf, buflen, 0);
395# elif (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
396 return sysctl_random(buf, buflen);
397# elif (defined(__DragonFly__) && __DragonFly_version >= 500700) \
398 || (defined(__NetBSD__) && __NetBSD_Version >= 1000000000)
399 return getrandom(buf, buflen, 0);
400# else
401 errno = ENOSYS;
402 return -1;
403# endif
404}
405# endif /* defined(OPENSSL_RAND_SEED_GETRANDOM) */
406
407# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
408static const char *random_device_paths[] = { DEVRANDOM };
409static struct random_device {
410 int fd;
411 dev_t dev;
412 ino_t ino;
413 mode_t mode;
414 dev_t rdev;
415} random_devices[OSSL_NELEM(random_device_paths)];
416static int keep_random_devices_open = 1;
417
418# if defined(__linux) && defined(DEVRANDOM_WAIT) \
419 && defined(OPENSSL_RAND_SEED_GETRANDOM)
420static void *shm_addr;
421
422static void cleanup_shm(void)
423{
424 shmdt(shm_addr);
425}
426
427/*
428 * Ensure that the system randomness source has been adequately seeded.
429 * This is done by having the first start of libcrypto, wait until the device
430 * /dev/random becomes able to supply a byte of entropy. Subsequent starts
431 * of the library and later reseedings do not need to do this.
432 */
433static int wait_random_seeded(void)
434{
435 static int seeded = OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID < 0;
436 static const int kernel_version[] = { DEVRANDOM_SAFE_KERNEL };
437 int kernel[2];
438 int shm_id, fd, r;
439 char c, *p;
440 struct utsname un;
441 fd_set fds;
442
443 if (!seeded) {
444 /* See if anything has created the global seeded indication */
445 if ((shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1, 0)) == -1) {
446 /*
447 * Check the kernel's version and fail if it is too recent.
448 *
449 * Linux kernels from 4.8 onwards do not guarantee that
450 * /dev/urandom is properly seeded when /dev/random becomes
451 * readable. However, such kernels support the getentropy(2)
452 * system call and this should always succeed which renders
453 * this alternative but essentially identical source moot.
454 */
455 if (uname(&un) == 0) {
456 kernel[0] = atoi(un.release);
457 p = strchr(un.release, '.');
458 kernel[1] = p == NULL ? 0 : atoi(p + 1);
459 if (kernel[0] > kernel_version[0]
460 || (kernel[0] == kernel_version[0]
461 && kernel[1] >= kernel_version[1])) {
462 return 0;
463 }
464 }
465 /* Open /dev/random and wait for it to be readable */
466 if ((fd = open(DEVRANDOM_WAIT, O_RDONLY)) != -1) {
467 if (DEVRANDM_WAIT_USE_SELECT && fd < FD_SETSIZE) {
468 FD_ZERO(&fds);
469 FD_SET(fd, &fds);
470 while ((r = select(fd + 1, &fds, NULL, NULL, NULL)) < 0
471 && errno == EINTR);
472 } else {
473 while ((r = read(fd, &c, 1)) < 0 && errno == EINTR);
474 }
475 close(fd);
476 if (r == 1) {
477 seeded = 1;
478 /* Create the shared memory indicator */
479 shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1,
480 IPC_CREAT | S_IRUSR | S_IRGRP | S_IROTH);
481 }
482 }
483 }
484 if (shm_id != -1) {
485 seeded = 1;
486 /*
487 * Map the shared memory to prevent its premature destruction.
488 * If this call fails, it isn't a big problem.
489 */
490 shm_addr = shmat(shm_id, NULL, SHM_RDONLY);
491 if (shm_addr != (void *)-1)
492 OPENSSL_atexit(&cleanup_shm);
493 }
494 }
495 return seeded;
496}
497# else /* defined __linux && DEVRANDOM_WAIT && OPENSSL_RAND_SEED_GETRANDOM */
498static int wait_random_seeded(void)
499{
500 return 1;
501}
502# endif
503
504/*
505 * Verify that the file descriptor associated with the random source is
506 * still valid. The rationale for doing this is the fact that it is not
507 * uncommon for daemons to close all open file handles when daemonizing.
508 * So the handle might have been closed or even reused for opening
509 * another file.
510 */
511static int check_random_device(struct random_device * rd)
512{
513 struct stat st;
514
515 return rd->fd != -1
516 && fstat(rd->fd, &st) != -1
517 && rd->dev == st.st_dev
518 && rd->ino == st.st_ino
519 && ((rd->mode ^ st.st_mode) & ~(S_IRWXU | S_IRWXG | S_IRWXO)) == 0
520 && rd->rdev == st.st_rdev;
521}
522
523/*
524 * Open a random device if required and return its file descriptor or -1 on error
525 */
526static int get_random_device(size_t n)
527{
528 struct stat st;
529 struct random_device * rd = &random_devices[n];
530
531 /* reuse existing file descriptor if it is (still) valid */
532 if (check_random_device(rd))
533 return rd->fd;
534
535 /* open the random device ... */
536 if ((rd->fd = open(random_device_paths[n], O_RDONLY)) == -1)
537 return rd->fd;
538
539 /* ... and cache its relevant stat(2) data */
540 if (fstat(rd->fd, &st) != -1) {
541 rd->dev = st.st_dev;
542 rd->ino = st.st_ino;
543 rd->mode = st.st_mode;
544 rd->rdev = st.st_rdev;
545 } else {
546 close(rd->fd);
547 rd->fd = -1;
548 }
549
550 return rd->fd;
551}
552
553/*
554 * Close a random device making sure it is a random device
555 */
556static void close_random_device(size_t n)
557{
558 struct random_device * rd = &random_devices[n];
559
560 if (check_random_device(rd))
561 close(rd->fd);
562 rd->fd = -1;
563}
564
565int ossl_rand_pool_init(void)
566{
567 size_t i;
568
569 for (i = 0; i < OSSL_NELEM(random_devices); i++)
570 random_devices[i].fd = -1;
571
572 return 1;
573}
574
575void ossl_rand_pool_cleanup(void)
576{
577 size_t i;
578
579 for (i = 0; i < OSSL_NELEM(random_devices); i++)
580 close_random_device(i);
581}
582
583void ossl_rand_pool_keep_random_devices_open(int keep)
584{
585 if (!keep)
586 ossl_rand_pool_cleanup();
587
588 keep_random_devices_open = keep;
589}
590
591# else /* !defined(OPENSSL_RAND_SEED_DEVRANDOM) */
592
593int ossl_rand_pool_init(void)
594{
595 return 1;
596}
597
598void ossl_rand_pool_cleanup(void)
599{
600}
601
602void ossl_rand_pool_keep_random_devices_open(int keep)
603{
604}
605
606# endif /* defined(OPENSSL_RAND_SEED_DEVRANDOM) */
607
608/*
609 * Try the various seeding methods in turn, exit when successful.
610 *
611 * If more than one entropy source is available, is it
612 * preferable to stop as soon as enough entropy has been collected
613 * (as favored by @rsalz) or should one rather be defensive and add
614 * more entropy than requested and/or from different sources?
615 *
616 * Currently, the user can select multiple entropy sources in the
617 * configure step, yet in practice only the first available source
618 * will be used. A more flexible solution has been requested, but
619 * currently it is not clear how this can be achieved without
620 * overengineering the problem. There are many parameters which
621 * could be taken into account when selecting the order and amount
622 * of input from the different entropy sources (trust, quality,
623 * possibility of blocking).
624 */
625size_t ossl_pool_acquire_entropy(RAND_POOL *pool)
626{
627# if defined(OPENSSL_RAND_SEED_NONE)
628 return ossl_rand_pool_entropy_available(pool);
629# else
630 size_t entropy_available = 0;
631
632 (void)entropy_available; /* avoid compiler warning */
633
634# if defined(OPENSSL_RAND_SEED_GETRANDOM)
635 {
636 size_t bytes_needed;
637 unsigned char *buffer;
638 ssize_t bytes;
639 /* Maximum allowed number of consecutive unsuccessful attempts */
640 int attempts = 3;
641
642 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
643 while (bytes_needed != 0 && attempts-- > 0) {
644 buffer = ossl_rand_pool_add_begin(pool, bytes_needed);
645 bytes = syscall_random(buffer, bytes_needed);
646 if (bytes > 0) {
647 ossl_rand_pool_add_end(pool, bytes, 8 * bytes);
648 bytes_needed -= bytes;
649 attempts = 3; /* reset counter after successful attempt */
650 } else if (bytes < 0 && errno != EINTR) {
651 break;
652 }
653 }
654 }
655 entropy_available = ossl_rand_pool_entropy_available(pool);
656 if (entropy_available > 0)
657 return entropy_available;
658# endif
659
660# if defined(OPENSSL_RAND_SEED_LIBRANDOM)
661 {
662 /* Not yet implemented. */
663 }
664# endif
665
666# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
667 if (wait_random_seeded()) {
668 size_t bytes_needed;
669 unsigned char *buffer;
670 size_t i;
671
672 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
673 for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths);
674 i++) {
675 ssize_t bytes = 0;
676 /* Maximum number of consecutive unsuccessful attempts */
677 int attempts = 3;
678 const int fd = get_random_device(i);
679
680 if (fd == -1)
681 continue;
682
683 while (bytes_needed != 0 && attempts-- > 0) {
684 buffer = ossl_rand_pool_add_begin(pool, bytes_needed);
685 bytes = read(fd, buffer, bytes_needed);
686
687 if (bytes > 0) {
688 ossl_rand_pool_add_end(pool, bytes, 8 * bytes);
689 bytes_needed -= bytes;
690 attempts = 3; /* reset counter on successful attempt */
691 } else if (bytes < 0 && errno != EINTR) {
692 break;
693 }
694 }
695 if (bytes < 0 || !keep_random_devices_open)
696 close_random_device(i);
697
698 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1);
699 }
700 entropy_available = ossl_rand_pool_entropy_available(pool);
701 if (entropy_available > 0)
702 return entropy_available;
703 }
704# endif
705
706# if defined(OPENSSL_RAND_SEED_RDTSC)
707 entropy_available = ossl_prov_acquire_entropy_from_tsc(pool);
708 if (entropy_available > 0)
709 return entropy_available;
710# endif
711
712# if defined(OPENSSL_RAND_SEED_RDCPU)
713 entropy_available = ossl_prov_acquire_entropy_from_cpu(pool);
714 if (entropy_available > 0)
715 return entropy_available;
716# endif
717
718# if defined(OPENSSL_RAND_SEED_EGD)
719 {
720 static const char *paths[] = { DEVRANDOM_EGD, NULL };
721 size_t bytes_needed;
722 unsigned char *buffer;
723 int i;
724
725 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
726 for (i = 0; bytes_needed > 0 && paths[i] != NULL; i++) {
727 size_t bytes = 0;
728 int num;
729
730 buffer = ossl_rand_pool_add_begin(pool, bytes_needed);
731 num = RAND_query_egd_bytes(paths[i],
732 buffer, (int)bytes_needed);
733 if (num == (int)bytes_needed)
734 bytes = bytes_needed;
735
736 ossl_rand_pool_add_end(pool, bytes, 8 * bytes);
737 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1);
738 }
739 entropy_available = ossl_rand_pool_entropy_available(pool);
740 if (entropy_available > 0)
741 return entropy_available;
742 }
743# endif
744
745 return ossl_rand_pool_entropy_available(pool);
746# endif
747}
748# endif
749#endif
750
751#if (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS)) \
752 || defined(__DJGPP__)
753int ossl_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;
760
761 /* Erase the entire structure including any padding */
762 memset(&data, 0, sizeof(data));
763
764 /*
765 * Add process id, thread id, and a high resolution timestamp to
766 * ensure that the nonce is unique with high probability for
767 * different process instances.
768 */
769 data.pid = getpid();
770 data.tid = CRYPTO_THREAD_get_current_id();
771 data.time = get_time_stamp();
772
773 return ossl_rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
774}
775
776/*
777 * Get the current time with the highest possible resolution
778 *
779 * The time stamp is added to the nonce, so it is optimized for not repeating.
780 * The current time is ideal for this purpose, provided the computer's clock
781 * is synchronized.
782 */
783static uint64_t get_time_stamp(void)
784{
785# if defined(OSSL_POSIX_TIMER_OKAY)
786 {
787 struct timespec ts;
788
789 if (clock_gettime(CLOCK_REALTIME, &ts) == 0)
790 return TWO32TO64(ts.tv_sec, ts.tv_nsec);
791 }
792# endif
793# if defined(__unix__) \
794 || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
795 {
796 struct timeval tv;
797
798 if (gettimeofday(&tv, NULL) == 0)
799 return TWO32TO64(tv.tv_sec, tv.tv_usec);
800 }
801# endif
802 return time(NULL);
803}
804
805#endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS))
806 || defined(__DJGPP__) */
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