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source: vbox/trunk/src/libs/openssl-1.1.1l/crypto/rand/rand_unix.c@ 91772

Last change on this file since 91772 was 91772, checked in by vboxsync, 3 years ago

openssl-1.1.1l: Applied and adjusted our OpenSSL changes to 1.1.1l. bugref:10126
File size: 25.6 KB
Line 
1/*
2 * Copyright 1995-2021 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#if defined(__APPLE__)
38# include <CommonCrypto/CommonRandom.h>
39#endif
40
41#if defined(OPENSSL_SYS_UNIX) || defined(__DJGPP__)
42# include <sys/types.h>
43# include <sys/stat.h>
44# include <fcntl.h>
45# include <unistd.h>
46# include <sys/time.h>
47
48static uint64_t get_time_stamp(void);
49static uint64_t get_timer_bits(void);
50
51/* Macro to convert two thirty two bit values into a sixty four bit one */
52# define TWO32TO64(a, b) ((((uint64_t)(a)) << 32) + (b))
53
54/*
55 * Check for the existence and support of POSIX timers. The standard
56 * says that the _POSIX_TIMERS macro will have a positive value if they
57 * are available.
58 *
59 * However, we want an additional constraint: that the timer support does
60 * not require an extra library dependency. Early versions of glibc
61 * require -lrt to be specified on the link line to access the timers,
62 * so this needs to be checked for.
63 *
64 * It is worse because some libraries define __GLIBC__ but don't
65 * support the version testing macro (e.g. uClibc). This means
66 * an extra check is needed.
67 *
68 * The final condition is:
69 * "have posix timers and either not glibc or glibc without -lrt"
70 *
71 * The nested #if sequences are required to avoid using a parameterised
72 * macro that might be undefined.
73 */
74# undef OSSL_POSIX_TIMER_OKAY
75# if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
76# if defined(__GLIBC__)
77# if defined(__GLIBC_PREREQ)
78# if __GLIBC_PREREQ(2, 17)
79# define OSSL_POSIX_TIMER_OKAY
80# endif
81# endif
82# else
83# define OSSL_POSIX_TIMER_OKAY
84# endif
85# endif
86#endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS))
87 || defined(__DJGPP__) */
88
89#if defined(OPENSSL_RAND_SEED_NONE)
90/* none means none. this simplifies the following logic */
91# undef OPENSSL_RAND_SEED_OS
92# undef OPENSSL_RAND_SEED_GETRANDOM
93# undef OPENSSL_RAND_SEED_LIBRANDOM
94# undef OPENSSL_RAND_SEED_DEVRANDOM
95# undef OPENSSL_RAND_SEED_RDTSC
96# undef OPENSSL_RAND_SEED_RDCPU
97# undef OPENSSL_RAND_SEED_EGD
98#endif
99
100#if (defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI)) && \
101 !defined(OPENSSL_RAND_SEED_NONE)
102# error "UEFI and VXWorks only support seeding NONE"
103#endif
104
105#if defined(OPENSSL_SYS_VXWORKS)
106/* empty implementation */
107int rand_pool_init(void)
108{
109 return 1;
110}
111
112void rand_pool_cleanup(void)
113{
114}
115
116void rand_pool_keep_random_devices_open(int keep)
117{
118}
119
120size_t rand_pool_acquire_entropy(RAND_POOL *pool)
121{
122 return rand_pool_entropy_available(pool);
123}
124#endif
125
126#if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) \
127 || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) \
128 || defined(OPENSSL_SYS_UEFI))
129
130# if defined(OPENSSL_SYS_VOS)
131
132# ifndef OPENSSL_RAND_SEED_OS
133# error "Unsupported seeding method configured; must be os"
134# endif
135
136# if defined(OPENSSL_SYS_VOS_HPPA) && defined(OPENSSL_SYS_VOS_IA32)
137# error "Unsupported HP-PA and IA32 at the same time."
138# endif
139# if !defined(OPENSSL_SYS_VOS_HPPA) && !defined(OPENSSL_SYS_VOS_IA32)
140# error "Must have one of HP-PA or IA32"
141# endif
142
143/*
144 * The following algorithm repeatedly samples the real-time clock (RTC) to
145 * generate a sequence of unpredictable data. The algorithm relies upon the
146 * uneven execution speed of the code (due to factors such as cache misses,
147 * interrupts, bus activity, and scheduling) and upon the rather large
148 * relative difference between the speed of the clock and the rate at which
149 * it can be read. If it is ported to an environment where execution speed
150 * is more constant or where the RTC ticks at a much slower rate, or the
151 * clock can be read with fewer instructions, it is likely that the results
152 * would be far more predictable. This should only be used for legacy
153 * platforms.
154 *
155 * As a precaution, we assume only 2 bits of entropy per byte.
156 */
157size_t rand_pool_acquire_entropy(RAND_POOL *pool)
158{
159 short int code;
160 int i, k;
161 size_t bytes_needed;
162 struct timespec ts;
163 unsigned char v;
164# ifdef OPENSSL_SYS_VOS_HPPA
165 long duration;
166 extern void s$sleep(long *_duration, short int *_code);
167# else
168 long long duration;
169 extern void s$sleep2(long long *_duration, short int *_code);
170# endif
171
172 bytes_needed = rand_pool_bytes_needed(pool, 4 /*entropy_factor*/);
173
174 for (i = 0; i < bytes_needed; i++) {
175 /*
176 * burn some cpu; hope for interrupts, cache collisions, bus
177 * interference, etc.
178 */
179 for (k = 0; k < 99; k++)
180 ts.tv_nsec = random();
181
182# ifdef OPENSSL_SYS_VOS_HPPA
183 /* sleep for 1/1024 of a second (976 us). */
184 duration = 1;
185 s$sleep(&duration, &code);
186# else
187 /* sleep for 1/65536 of a second (15 us). */
188 duration = 1;
189 s$sleep2(&duration, &code);
190# endif
191
192 /* Get wall clock time, take 8 bits. */
193 clock_gettime(CLOCK_REALTIME, &ts);
194 v = (unsigned char)(ts.tv_nsec & 0xFF);
195 rand_pool_add(pool, arg, &v, sizeof(v) , 2);
196 }
197 return rand_pool_entropy_available(pool);
198}
199
200void rand_pool_cleanup(void)
201{
202}
203
204void rand_pool_keep_random_devices_open(int keep)
205{
206}
207
208# else
209
210# if defined(OPENSSL_RAND_SEED_EGD) && \
211 (defined(OPENSSL_NO_EGD) || !defined(DEVRANDOM_EGD))
212# error "Seeding uses EGD but EGD is turned off or no device given"
213# endif
214
215# if defined(OPENSSL_RAND_SEED_DEVRANDOM) && !defined(DEVRANDOM)
216# error "Seeding uses urandom but DEVRANDOM is not configured"
217# endif
218
219# if defined(OPENSSL_RAND_SEED_OS)
220# if !defined(DEVRANDOM)
221# error "OS seeding requires DEVRANDOM to be configured"
222# endif
223# define OPENSSL_RAND_SEED_GETRANDOM
224# define OPENSSL_RAND_SEED_DEVRANDOM
225# endif
226
227# if defined(OPENSSL_RAND_SEED_LIBRANDOM)
228# error "librandom not (yet) supported"
229# endif
230
231# if (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
232/*
233 * sysctl_random(): Use sysctl() to read a random number from the kernel
234 * Returns the number of bytes returned in buf on success, -1 on failure.
235 */
236static ssize_t sysctl_random(char *buf, size_t buflen)
237{
238 int mib[2];
239 size_t done = 0;
240 size_t len;
241
242 /*
243 * Note: sign conversion between size_t and ssize_t is safe even
244 * without a range check, see comment in syscall_random()
245 */
246
247 /*
248 * On FreeBSD old implementations returned longs, newer versions support
249 * variable sizes up to 256 byte. The code below would not work properly
250 * when the sysctl returns long and we want to request something not a
251 * multiple of longs, which should never be the case.
252 */
253#if defined(__FreeBSD__)
254 if (!ossl_assert(buflen % sizeof(long) == 0)) {
255 errno = EINVAL;
256 return -1;
257 }
258#endif
259
260 /*
261 * On NetBSD before 4.0 KERN_ARND was an alias for KERN_URND, and only
262 * filled in an int, leaving the rest uninitialized. Since NetBSD 4.0
263 * it returns a variable number of bytes with the current version supporting
264 * up to 256 bytes.
265 * Just return an error on older NetBSD versions.
266 */
267#if defined(__NetBSD__) && __NetBSD_Version__ < 400000000
268 errno = ENOSYS;
269 return -1;
270#endif
271
272 mib[0] = CTL_KERN;
273 mib[1] = KERN_ARND;
274
275 do {
276 len = buflen > 256 ? 256 : buflen;
277 if (sysctl(mib, 2, buf, &len, NULL, 0) == -1)
278 return done > 0 ? done : -1;
279 done += len;
280 buf += len;
281 buflen -= len;
282 } while (buflen > 0);
283
284 return done;
285}
286# endif
287
288# if defined(OPENSSL_RAND_SEED_GETRANDOM)
289
290# if defined(__linux) && !defined(__NR_getrandom)
291# if defined(__arm__)
292# define __NR_getrandom (__NR_SYSCALL_BASE+384)
293# elif defined(__i386__)
294# define __NR_getrandom 355
295# elif defined(__x86_64__)
296# if defined(__ILP32__)
297# define __NR_getrandom (__X32_SYSCALL_BIT + 318)
298# else
299# define __NR_getrandom 318
300# endif
301# elif defined(__xtensa__)
302# define __NR_getrandom 338
303# elif defined(__s390__) || defined(__s390x__)
304# define __NR_getrandom 349
305# elif defined(__bfin__)
306# define __NR_getrandom 389
307# elif defined(__powerpc__)
308# define __NR_getrandom 359
309# elif defined(__mips__) || defined(__mips64)
310# if _MIPS_SIM == _MIPS_SIM_ABI32
311# define __NR_getrandom (__NR_Linux + 353)
312# elif _MIPS_SIM == _MIPS_SIM_ABI64
313# define __NR_getrandom (__NR_Linux + 313)
314# elif _MIPS_SIM == _MIPS_SIM_NABI32
315# define __NR_getrandom (__NR_Linux + 317)
316# endif
317# elif defined(__hppa__)
318# define __NR_getrandom (__NR_Linux + 339)
319# elif defined(__sparc__)
320# define __NR_getrandom 347
321# elif defined(__ia64__)
322# define __NR_getrandom 1339
323# elif defined(__alpha__)
324# define __NR_getrandom 511
325# elif defined(__sh__)
326# if defined(__SH5__)
327# define __NR_getrandom 373
328# else
329# define __NR_getrandom 384
330# endif
331# elif defined(__avr32__)
332# define __NR_getrandom 317
333# elif defined(__microblaze__)
334# define __NR_getrandom 385
335# elif defined(__m68k__)
336# define __NR_getrandom 352
337# elif defined(__cris__)
338# define __NR_getrandom 356
339# elif defined(__aarch64__)
340# define __NR_getrandom 278
341# else /* generic */
342# define __NR_getrandom 278
343# endif
344# endif
345
346/*
347 * syscall_random(): Try to get random data using a system call
348 * returns the number of bytes returned in buf, or < 0 on error.
349 */
350static ssize_t syscall_random(void *buf, size_t buflen)
351{
352 /*
353 * Note: 'buflen' equals the size of the buffer which is used by the
354 * get_entropy() callback of the RAND_DRBG. It is roughly bounded by
355 *
356 * 2 * RAND_POOL_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^14
357 *
358 * which is way below the OSSL_SSIZE_MAX limit. Therefore sign conversion
359 * between size_t and ssize_t is safe even without a range check.
360 */
361
362 /*
363 * Do runtime detection to find getentropy().
364 *
365 * Known OSs that should support this:
366 * - Darwin since 16 (OSX 10.12, IOS 10.0).
367 * - Solaris since 11.3
368 * - OpenBSD since 5.6
369 * - Linux since 3.17 with glibc 2.25
370 * - FreeBSD since 12.0 (1200061)
371 *
372 * Note: Sometimes getentropy() can be provided but not implemented
373 * internally. So we need to check errno for ENOSYS
374 */
375# if defined(__GNUC__) && __GNUC__>=2 && defined(__ELF__) && !defined(__hpux)
376 extern int getentropy(void *buffer, size_t length) __attribute__((weak));
377
378 if (getentropy != NULL) {
379 if (getentropy(buf, buflen) == 0)
380 return (ssize_t)buflen;
381 if (errno != ENOSYS)
382 return -1;
383 }
384# elif defined(__APPLE__)
385 if (CCRandomGenerateBytes(buf, buflen) == kCCSuccess)
386 return (ssize_t)buflen;
387
388 return -1;
389# else
390 union {
391 void *p;
392 int (*f)(void *buffer, size_t length);
393 } p_getentropy;
394
395 /*
396 * We could cache the result of the lookup, but we normally don't
397 * call this function often.
398 */
399 ERR_set_mark();
400 p_getentropy.p = DSO_global_lookup("getentropy");
401 ERR_pop_to_mark();
402 if (p_getentropy.p != NULL)
403 return p_getentropy.f(buf, buflen) == 0 ? (ssize_t)buflen : -1;
404# endif
405
406 /* Linux supports this since version 3.17 */
407# if defined(__linux) && defined(__NR_getrandom)
408 return syscall(__NR_getrandom, buf, buflen, 0);
409# elif (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
410 return sysctl_random(buf, buflen);
411# else
412 errno = ENOSYS;
413 return -1;
414# endif
415}
416# endif /* defined(OPENSSL_RAND_SEED_GETRANDOM) */
417
418# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
419static const char *random_device_paths[] = { DEVRANDOM };
420static struct random_device {
421 int fd;
422 dev_t dev;
423 ino_t ino;
424 mode_t mode;
425 dev_t rdev;
426} random_devices[OSSL_NELEM(random_device_paths)];
427static int keep_random_devices_open = 1;
428
429# if defined(__linux) && defined(DEVRANDOM_WAIT) \
430 && defined(OPENSSL_RAND_SEED_GETRANDOM)
431static void *shm_addr;
432
433static void cleanup_shm(void)
434{
435 shmdt(shm_addr);
436}
437
438/*
439 * Ensure that the system randomness source has been adequately seeded.
440 * This is done by having the first start of libcrypto, wait until the device
441 * /dev/random becomes able to supply a byte of entropy. Subsequent starts
442 * of the library and later reseedings do not need to do this.
443 */
444static int wait_random_seeded(void)
445{
446 static int seeded = OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID < 0;
447 static const int kernel_version[] = { DEVRANDOM_SAFE_KERNEL };
448 int kernel[2];
449 int shm_id, fd, r;
450 char c, *p;
451 struct utsname un;
452 fd_set fds;
453
454 if (!seeded) {
455 /* See if anything has created the global seeded indication */
456 if ((shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1, 0)) == -1) {
457 /*
458 * Check the kernel's version and fail if it is too recent.
459 *
460 * Linux kernels from 4.8 onwards do not guarantee that
461 * /dev/urandom is properly seeded when /dev/random becomes
462 * readable. However, such kernels support the getentropy(2)
463 * system call and this should always succeed which renders
464 * this alternative but essentially identical source moot.
465 */
466 if (uname(&un) == 0) {
467 kernel[0] = atoi(un.release);
468 p = strchr(un.release, '.');
469 kernel[1] = p == NULL ? 0 : atoi(p + 1);
470 if (kernel[0] > kernel_version[0]
471 || (kernel[0] == kernel_version[0]
472 && kernel[1] >= kernel_version[1])) {
473 return 0;
474 }
475 }
476 /* Open /dev/random and wait for it to be readable */
477 if ((fd = open(DEVRANDOM_WAIT, O_RDONLY)) != -1) {
478 if (DEVRANDM_WAIT_USE_SELECT && fd < FD_SETSIZE) {
479 FD_ZERO(&fds);
480 FD_SET(fd, &fds);
481 while ((r = select(fd + 1, &fds, NULL, NULL, NULL)) < 0
482 && errno == EINTR);
483 } else {
484 while ((r = read(fd, &c, 1)) < 0 && errno == EINTR);
485 }
486 close(fd);
487 if (r == 1) {
488 seeded = 1;
489 /* Create the shared memory indicator */
490 shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1,
491 IPC_CREAT | S_IRUSR | S_IRGRP | S_IROTH);
492 }
493 }
494 }
495 if (shm_id != -1) {
496 seeded = 1;
497 /*
498 * Map the shared memory to prevent its premature destruction.
499 * If this call fails, it isn't a big problem.
500 */
501 shm_addr = shmat(shm_id, NULL, SHM_RDONLY);
502 if (shm_addr != (void *)-1)
503 OPENSSL_atexit(&cleanup_shm);
504 }
505 }
506 return seeded;
507}
508# else /* defined __linux && DEVRANDOM_WAIT && OPENSSL_RAND_SEED_GETRANDOM */
509static int wait_random_seeded(void)
510{
511 return 1;
512}
513# endif
514
515/*
516 * Verify that the file descriptor associated with the random source is
517 * still valid. The rationale for doing this is the fact that it is not
518 * uncommon for daemons to close all open file handles when daemonizing.
519 * So the handle might have been closed or even reused for opening
520 * another file.
521 */
522static int check_random_device(struct random_device * rd)
523{
524 struct stat st;
525
526 return rd->fd != -1
527 && fstat(rd->fd, &st) != -1
528 && rd->dev == st.st_dev
529 && rd->ino == st.st_ino
530 && ((rd->mode ^ st.st_mode) & ~(S_IRWXU | S_IRWXG | S_IRWXO)) == 0
531 && rd->rdev == st.st_rdev;
532}
533
534/*
535 * Open a random device if required and return its file descriptor or -1 on error
536 */
537static int get_random_device(size_t n)
538{
539 struct stat st;
540 struct random_device * rd = &random_devices[n];
541
542 /* reuse existing file descriptor if it is (still) valid */
543 if (check_random_device(rd))
544 return rd->fd;
545
546 /* open the random device ... */
547 if ((rd->fd = open(random_device_paths[n], O_RDONLY)) == -1)
548 return rd->fd;
549
550 /* ... and cache its relevant stat(2) data */
551 if (fstat(rd->fd, &st) != -1) {
552 rd->dev = st.st_dev;
553 rd->ino = st.st_ino;
554 rd->mode = st.st_mode;
555 rd->rdev = st.st_rdev;
556 } else {
557 close(rd->fd);
558 rd->fd = -1;
559 }
560
561 return rd->fd;
562}
563
564/*
565 * Close a random device making sure it is a random device
566 */
567static void close_random_device(size_t n)
568{
569 struct random_device * rd = &random_devices[n];
570
571 if (check_random_device(rd))
572 close(rd->fd);
573 rd->fd = -1;
574}
575
576int rand_pool_init(void)
577{
578 size_t i;
579
580 for (i = 0; i < OSSL_NELEM(random_devices); i++)
581 random_devices[i].fd = -1;
582
583 return 1;
584}
585
586void rand_pool_cleanup(void)
587{
588 size_t i;
589
590 for (i = 0; i < OSSL_NELEM(random_devices); i++)
591 close_random_device(i);
592}
593
594void rand_pool_keep_random_devices_open(int keep)
595{
596 if (!keep)
597 rand_pool_cleanup();
598
599 keep_random_devices_open = keep;
600}
601
602# else /* !defined(OPENSSL_RAND_SEED_DEVRANDOM) */
603
604int rand_pool_init(void)
605{
606 return 1;
607}
608
609void rand_pool_cleanup(void)
610{
611}
612
613void rand_pool_keep_random_devices_open(int keep)
614{
615}
616
617# endif /* defined(OPENSSL_RAND_SEED_DEVRANDOM) */
618
619/*
620 * Try the various seeding methods in turn, exit when successful.
621 *
622 * TODO(DRBG): If more than one entropy source is available, is it
623 * preferable to stop as soon as enough entropy has been collected
624 * (as favored by @rsalz) or should one rather be defensive and add
625 * more entropy than requested and/or from different sources?
626 *
627 * Currently, the user can select multiple entropy sources in the
628 * configure step, yet in practice only the first available source
629 * will be used. A more flexible solution has been requested, but
630 * currently it is not clear how this can be achieved without
631 * overengineering the problem. There are many parameters which
632 * could be taken into account when selecting the order and amount
633 * of input from the different entropy sources (trust, quality,
634 * possibility of blocking).
635 */
636size_t rand_pool_acquire_entropy(RAND_POOL *pool)
637{
638# if defined(OPENSSL_RAND_SEED_NONE)
639 return rand_pool_entropy_available(pool);
640# else
641 size_t entropy_available;
642
643# if defined(OPENSSL_RAND_SEED_GETRANDOM)
644 {
645 size_t bytes_needed;
646 unsigned char *buffer;
647 ssize_t bytes;
648 /* Maximum allowed number of consecutive unsuccessful attempts */
649 int attempts = 3;
650
651 bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
652 while (bytes_needed != 0 && attempts-- > 0) {
653 buffer = rand_pool_add_begin(pool, bytes_needed);
654 bytes = syscall_random(buffer, bytes_needed);
655 if (bytes > 0) {
656 rand_pool_add_end(pool, bytes, 8 * bytes);
657 bytes_needed -= bytes;
658 attempts = 3; /* reset counter after successful attempt */
659 } else if (bytes < 0 && errno != EINTR) {
660 break;
661 }
662 }
663 }
664 entropy_available = rand_pool_entropy_available(pool);
665 if (entropy_available > 0)
666 return entropy_available;
667# endif
668
669# if defined(OPENSSL_RAND_SEED_LIBRANDOM)
670 {
671 /* Not yet implemented. */
672 }
673# endif
674
675# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
676 if (wait_random_seeded()) {
677 size_t bytes_needed;
678 unsigned char *buffer;
679 size_t i;
680
681 bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
682 for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths);
683 i++) {
684 ssize_t bytes = 0;
685 /* Maximum number of consecutive unsuccessful attempts */
686 int attempts = 3;
687 const int fd = get_random_device(i);
688
689 if (fd == -1)
690 continue;
691
692 while (bytes_needed != 0 && attempts-- > 0) {
693 buffer = rand_pool_add_begin(pool, bytes_needed);
694 bytes = read(fd, buffer, bytes_needed);
695
696 if (bytes > 0) {
697 rand_pool_add_end(pool, bytes, 8 * bytes);
698 bytes_needed -= bytes;
699 attempts = 3; /* reset counter on successful attempt */
700 } else if (bytes < 0 && errno != EINTR) {
701 break;
702 }
703 }
704 if (bytes < 0 || !keep_random_devices_open)
705 close_random_device(i);
706
707 bytes_needed = rand_pool_bytes_needed(pool, 1);
708 }
709 entropy_available = rand_pool_entropy_available(pool);
710 if (entropy_available > 0)
711 return entropy_available;
712 }
713# endif
714
715# if defined(OPENSSL_RAND_SEED_RDTSC)
716 entropy_available = rand_acquire_entropy_from_tsc(pool);
717 if (entropy_available > 0)
718 return entropy_available;
719# endif
720
721# if defined(OPENSSL_RAND_SEED_RDCPU)
722 entropy_available = rand_acquire_entropy_from_cpu(pool);
723 if (entropy_available > 0)
724 return entropy_available;
725# endif
726
727# if defined(OPENSSL_RAND_SEED_EGD)
728 {
729 static const char *paths[] = { DEVRANDOM_EGD, NULL };
730 size_t bytes_needed;
731 unsigned char *buffer;
732 int i;
733
734 bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
735 for (i = 0; bytes_needed > 0 && paths[i] != NULL; i++) {
736 size_t bytes = 0;
737 int num;
738
739 buffer = rand_pool_add_begin(pool, bytes_needed);
740 num = RAND_query_egd_bytes(paths[i],
741 buffer, (int)bytes_needed);
742 if (num == (int)bytes_needed)
743 bytes = bytes_needed;
744
745 rand_pool_add_end(pool, bytes, 8 * bytes);
746 bytes_needed = rand_pool_bytes_needed(pool, 1);
747 }
748 entropy_available = rand_pool_entropy_available(pool);
749 if (entropy_available > 0)
750 return entropy_available;
751 }
752# endif
753
754 return rand_pool_entropy_available(pool);
755# endif
756}
757# endif
758#endif
759
760#if defined(OPENSSL_SYS_UNIX) || defined(__DJGPP__)
761int rand_pool_add_nonce_data(RAND_POOL *pool)
762{
763 struct {
764 pid_t pid;
765 CRYPTO_THREAD_ID tid;
766 uint64_t time;
767 } data = { 0 };
768
769 /*
770 * Add process id, thread id, and a high resolution timestamp to
771 * ensure that the nonce is unique with high probability for
772 * different process instances.
773 */
774 data.pid = getpid();
775 data.tid = CRYPTO_THREAD_get_current_id();
776 data.time = get_time_stamp();
777
778 return rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
779}
780
781int rand_pool_add_additional_data(RAND_POOL *pool)
782{
783 struct {
784 int fork_id;
785 CRYPTO_THREAD_ID tid;
786 uint64_t time;
787 } data = { 0 };
788
789 /*
790 * Add some noise from the thread id and a high resolution timer.
791 * The fork_id adds some extra fork-safety.
792 * The thread id adds a little randomness if the drbg is accessed
793 * concurrently (which is the case for the <master> drbg).
794 */
795 data.fork_id = openssl_get_fork_id();
796 data.tid = CRYPTO_THREAD_get_current_id();
797 data.time = get_timer_bits();
798
799 return rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
800}
801
802
803/*
804 * Get the current time with the highest possible resolution
805 *
806 * The time stamp is added to the nonce, so it is optimized for not repeating.
807 * The current time is ideal for this purpose, provided the computer's clock
808 * is synchronized.
809 */
810static uint64_t get_time_stamp(void)
811{
812# if defined(OSSL_POSIX_TIMER_OKAY)
813 {
814 struct timespec ts;
815
816 if (clock_gettime(CLOCK_REALTIME, &ts) == 0)
817 return TWO32TO64(ts.tv_sec, ts.tv_nsec);
818 }
819# endif
820# if defined(__unix__) \
821 || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
822 {
823 struct timeval tv;
824
825 if (gettimeofday(&tv, NULL) == 0)
826 return TWO32TO64(tv.tv_sec, tv.tv_usec);
827 }
828# endif
829 return time(NULL);
830}
831
832/*
833 * Get an arbitrary timer value of the highest possible resolution
834 *
835 * The timer value is added as random noise to the additional data,
836 * which is not considered a trusted entropy sourec, so any result
837 * is acceptable.
838 */
839static uint64_t get_timer_bits(void)
840{
841 uint64_t res = OPENSSL_rdtsc();
842
843 if (res != 0)
844 return res;
845
846# if defined(__sun) || defined(__hpux)
847 return gethrtime();
848# elif defined(_AIX)
849 {
850 timebasestruct_t t;
851
852 read_wall_time(&t, TIMEBASE_SZ);
853 return TWO32TO64(t.tb_high, t.tb_low);
854 }
855# elif defined(OSSL_POSIX_TIMER_OKAY)
856 {
857 struct timespec ts;
858
859# ifdef CLOCK_BOOTTIME
860# define CLOCK_TYPE CLOCK_BOOTTIME
861# elif defined(_POSIX_MONOTONIC_CLOCK)
862# define CLOCK_TYPE CLOCK_MONOTONIC
863# else
864# define CLOCK_TYPE CLOCK_REALTIME
865# endif
866
867 if (clock_gettime(CLOCK_TYPE, &ts) == 0)
868 return TWO32TO64(ts.tv_sec, ts.tv_nsec);
869 }
870# endif
871# if defined(__unix__) \
872 || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
873 {
874 struct timeval tv;
875
876 if (gettimeofday(&tv, NULL) == 0)
877 return TWO32TO64(tv.tv_sec, tv.tv_usec);
878 }
879# endif
880 return time(NULL);
881}
882#endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS))
883 || defined(__DJGPP__) */
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