1 /*
2 * Copyright 1995-2024 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 #ifndef OPENSSL_SYS_UEFI
25 #ifdef __linux
26 #include <sys/syscall.h>
27 #ifdef DEVRANDOM_WAIT
28 #include <sys/shm.h>
29 #include <sys/utsname.h>
30 #endif
31 #endif
32 #if defined(__FreeBSD__) || defined(__NetBSD__)
33 #include <sys/types.h>
34 #include <sys/sysctl.h>
35 #include <sys/param.h>
36 #endif
37 #if defined(__FreeBSD__) && __FreeBSD_version >= 1200061
38 #include <sys/random.h>
39 #endif
40 #if defined(__OpenBSD__)
41 #include <sys/param.h>
42 #endif
43 #if defined(__DragonFly__)
44 #include <sys/param.h>
45 #include <sys/random.h>
46 #endif
47 #endif
48
49 #if (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS)) \
50 || defined(__DJGPP__)
51 #include <sys/types.h>
52 #include <sys/stat.h>
53 #include <fcntl.h>
54 #include <unistd.h>
55 #include <sys/time.h>
56
57 static uint64_t get_time_stamp(void);
58
59 /* Macro to convert two thirty two bit values into a sixty four bit one */
60 #define TWO32TO64(a, b) ((((uint64_t)(a)) << 32) + (b))
61
62 /*
63 * Check for the existence and support of POSIX timers. The standard
64 * says that the _POSIX_TIMERS macro will have a positive value if they
65 * are available.
66 *
67 * However, we want an additional constraint: that the timer support does
68 * not require an extra library dependency. Early versions of glibc
69 * require -lrt to be specified on the link line to access the timers,
70 * so this needs to be checked for.
71 *
72 * It is worse because some libraries define __GLIBC__ but don't
73 * support the version testing macro (e.g. uClibc). This means
74 * an extra check is needed.
75 *
76 * The final condition is:
77 * "have posix timers and either not glibc or glibc without -lrt"
78 *
79 * The nested #if sequences are required to avoid using a parameterised
80 * macro that might be undefined.
81 */
82 #undef OSSL_POSIX_TIMER_OKAY
83 /* On some systems, _POSIX_TIMERS is defined but empty.
84 * Subtracting by 0 when comparing avoids an error in this case. */
85 #if defined(_POSIX_TIMERS) && _POSIX_TIMERS - 0 > 0
86 #if defined(__GLIBC__)
87 #if defined(__GLIBC_PREREQ)
88 #if __GLIBC_PREREQ(2, 17)
89 #define OSSL_POSIX_TIMER_OKAY
90 #endif
91 #endif
92 #else
93 #define OSSL_POSIX_TIMER_OKAY
94 #endif
95 #endif
96 #endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS)) \
97 || defined(__DJGPP__) */
98
99 #if defined(OPENSSL_RAND_SEED_NONE)
100 /* none means none. this simplifies the following logic */
101 #undef OPENSSL_RAND_SEED_OS
102 #undef OPENSSL_RAND_SEED_GETRANDOM
103 #undef OPENSSL_RAND_SEED_DEVRANDOM
104 #undef OPENSSL_RAND_SEED_RDTSC
105 #undef OPENSSL_RAND_SEED_RDCPU
106 #undef OPENSSL_RAND_SEED_EGD
107 #endif
108
109 #if defined(OPENSSL_SYS_UEFI) && !defined(OPENSSL_RAND_SEED_NONE)
110 #error "UEFI only supports seeding NONE"
111 #endif
112
113 #if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) \
114 || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) \
115 || defined(OPENSSL_SYS_UEFI))
116
117 #if defined(OPENSSL_SYS_VOS)
118
119 #ifndef OPENSSL_RAND_SEED_OS
120 #error "Unsupported seeding method configured; must be os"
121 #endif
122
123 #if defined(OPENSSL_SYS_VOS_HPPA) && defined(OPENSSL_SYS_VOS_IA32)
124 #error "Unsupported HP-PA and IA32 at the same time."
125 #endif
126 #if !defined(OPENSSL_SYS_VOS_HPPA) && !defined(OPENSSL_SYS_VOS_IA32)
127 #error "Must have one of HP-PA or IA32"
128 #endif
129
130 /*
131 * The following algorithm repeatedly samples the real-time clock (RTC) to
132 * generate a sequence of unpredictable data. The algorithm relies upon the
133 * uneven execution speed of the code (due to factors such as cache misses,
134 * interrupts, bus activity, and scheduling) and upon the rather large
135 * relative difference between the speed of the clock and the rate at which
136 * it can be read. If it is ported to an environment where execution speed
137 * is more constant or where the RTC ticks at a much slower rate, or the
138 * clock can be read with fewer instructions, it is likely that the results
139 * would be far more predictable. This should only be used for legacy
140 * platforms.
141 *
142 * As a precaution, we assume only 2 bits of entropy per byte.
143 */
ossl_pool_acquire_entropy(RAND_POOL * pool)144 size_t ossl_pool_acquire_entropy(RAND_POOL *pool)
145 {
146 short int code;
147 int i, k;
148 size_t bytes_needed;
149 struct timespec ts;
150 unsigned char v;
151 #ifdef OPENSSL_SYS_VOS_HPPA
152 long duration;
153 extern void s$sleep(long *_duration, short int *_code);
154 #else
155 long long duration;
156 extern void s$sleep2(long long *_duration, short int *_code);
157 #endif
158
159 bytes_needed = ossl_rand_pool_bytes_needed(pool, 4 /*entropy_factor*/);
160
161 for (i = 0; i < bytes_needed; i++) {
162 /*
163 * burn some cpu; hope for interrupts, cache collisions, bus
164 * interference, etc.
165 */
166 for (k = 0; k < 99; k++)
167 ts.tv_nsec = random();
168
169 #ifdef OPENSSL_SYS_VOS_HPPA
170 /* sleep for 1/1024 of a second (976 us). */
171 duration = 1;
172 s$sleep(&duration, &code);
173 #else
174 /* sleep for 1/65536 of a second (15 us). */
175 duration = 1;
176 s$sleep2(&duration, &code);
177 #endif
178
179 /* Get wall clock time, take 8 bits. */
180 clock_gettime(CLOCK_REALTIME, &ts);
181 v = (unsigned char)(ts.tv_nsec & 0xFF);
182 ossl_rand_pool_add(pool, arg, &v, sizeof(v), 2);
183 }
184 return ossl_rand_pool_entropy_available(pool);
185 }
186
ossl_rand_pool_cleanup(void)187 void ossl_rand_pool_cleanup(void)
188 {
189 }
190
ossl_rand_pool_keep_random_devices_open(int keep)191 void ossl_rand_pool_keep_random_devices_open(int keep)
192 {
193 }
194
195 #else
196
197 #if defined(OPENSSL_RAND_SEED_EGD) && (defined(OPENSSL_NO_EGD) || !defined(DEVRANDOM_EGD))
198 #error "Seeding uses EGD but EGD is turned off or no device given"
199 #endif
200
201 #if defined(OPENSSL_RAND_SEED_DEVRANDOM) && !defined(DEVRANDOM)
202 #error "Seeding uses urandom but DEVRANDOM is not configured"
203 #endif
204
205 #if defined(OPENSSL_RAND_SEED_OS)
206 #if !defined(DEVRANDOM)
207 #error "OS seeding requires DEVRANDOM to be configured"
208 #endif
209 #define OPENSSL_RAND_SEED_GETRANDOM
210 #define OPENSSL_RAND_SEED_DEVRANDOM
211 #endif
212
213 #if (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
214 /*
215 * sysctl_random(): Use sysctl() to read a random number from the kernel
216 * Returns the number of bytes returned in buf on success, -1 on failure.
217 */
sysctl_random(char * buf,size_t buflen)218 static ssize_t sysctl_random(char *buf, size_t buflen)
219 {
220 int mib[2];
221 size_t done = 0;
222 size_t len;
223
224 /*
225 * Note: sign conversion between size_t and ssize_t is safe even
226 * without a range check, see comment in syscall_random()
227 */
228
229 /*
230 * On FreeBSD old implementations returned longs, newer versions support
231 * variable sizes up to 256 byte. The code below would not work properly
232 * when the sysctl returns long and we want to request something not a
233 * multiple of longs, which should never be the case.
234 */
235 #if defined(__FreeBSD__)
236 if (!ossl_assert(buflen % sizeof(long) == 0)) {
237 errno = EINVAL;
238 return -1;
239 }
240 #endif
241
242 /*
243 * On NetBSD before 4.0 KERN_ARND was an alias for KERN_URND, and only
244 * filled in an int, leaving the rest uninitialized. Since NetBSD 4.0
245 * it returns a variable number of bytes with the current version supporting
246 * up to 256 bytes.
247 * Just return an error on older NetBSD versions.
248 */
249 #if defined(__NetBSD__) && __NetBSD_Version__ < 400000000
250 errno = ENOSYS;
251 return -1;
252 #endif
253
254 mib[0] = CTL_KERN;
255 mib[1] = KERN_ARND;
256
257 do {
258 len = buflen > 256 ? 256 : buflen;
259 if (sysctl(mib, 2, buf, &len, NULL, 0) == -1)
260 return done > 0 ? done : -1;
261 done += len;
262 buf += len;
263 buflen -= len;
264 } while (buflen > 0);
265
266 return done;
267 }
268 #endif
269
270 #if defined(OPENSSL_RAND_SEED_GETRANDOM)
271
272 #if defined(__linux) && !defined(__NR_getrandom)
273 #if defined(__arm__)
274 #define __NR_getrandom (__NR_SYSCALL_BASE + 384)
275 #elif defined(__i386__)
276 #define __NR_getrandom 355
277 #elif defined(__x86_64__)
278 #if defined(__ILP32__)
279 #define __NR_getrandom (__X32_SYSCALL_BIT + 318)
280 #else
281 #define __NR_getrandom 318
282 #endif
283 #elif defined(__xtensa__)
284 #define __NR_getrandom 338
285 #elif defined(__s390__) || defined(__s390x__)
286 #define __NR_getrandom 349
287 #elif defined(__bfin__)
288 #define __NR_getrandom 389
289 #elif defined(__powerpc__)
290 #define __NR_getrandom 359
291 #elif defined(__mips__) || defined(__mips64)
292 #if _MIPS_SIM == _MIPS_SIM_ABI32
293 #define __NR_getrandom (__NR_Linux + 353)
294 #elif _MIPS_SIM == _MIPS_SIM_ABI64
295 #define __NR_getrandom (__NR_Linux + 313)
296 #elif _MIPS_SIM == _MIPS_SIM_NABI32
297 #define __NR_getrandom (__NR_Linux + 317)
298 #endif
299 #elif defined(__hppa__)
300 #define __NR_getrandom (__NR_Linux + 339)
301 #elif defined(__sparc__)
302 #define __NR_getrandom 347
303 #elif defined(__ia64__)
304 #define __NR_getrandom 1339
305 #elif defined(__alpha__)
306 #define __NR_getrandom 511
307 #elif defined(__sh__)
308 #if defined(__SH5__)
309 #define __NR_getrandom 373
310 #else
311 #define __NR_getrandom 384
312 #endif
313 #elif defined(__avr32__)
314 #define __NR_getrandom 317
315 #elif defined(__microblaze__)
316 #define __NR_getrandom 385
317 #elif defined(__m68k__)
318 #define __NR_getrandom 352
319 #elif defined(__cris__)
320 #define __NR_getrandom 356
321 #else /* generic (f.e. aarch64, loongarch, loongarch64) */
322 #define __NR_getrandom 278
323 #endif
324 #endif
325
326 /*
327 * syscall_random(): Try to get random data using a system call
328 * returns the number of bytes returned in buf, or < 0 on error.
329 */
syscall_random(void * buf,size_t buflen)330 static ssize_t syscall_random(void *buf, size_t buflen)
331 {
332 /*
333 * Note: 'buflen' equals the size of the buffer which is used by the
334 * get_entropy() callback of the RAND_DRBG. It is roughly bounded by
335 *
336 * 2 * RAND_POOL_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^14
337 *
338 * which is way below the OSSL_SSIZE_MAX limit. Therefore sign conversion
339 * between size_t and ssize_t is safe even without a range check.
340 */
341
342 /*
343 * Do runtime detection to find getentropy().
344 *
345 * Known OSs that should support this:
346 * - Darwin since 16 (OSX 10.12, IOS 10.0).
347 * - Solaris since 11.3
348 * - OpenBSD since 5.6
349 * - Linux since 3.17 with glibc 2.25
350 *
351 * Note: Sometimes getentropy() can be provided but not implemented
352 * internally. So we need to check errno for ENOSYS
353 */
354 #if !defined(__DragonFly__) && !defined(__NetBSD__) && !defined(__FreeBSD__)
355 #if defined(__GNUC__) && __GNUC__ >= 2 && defined(__ELF__) && !defined(__hpux)
356 extern int getentropy(void *buffer, size_t length) __attribute__((weak));
357
358 if (getentropy != NULL) {
359 if (getentropy(buf, buflen) == 0)
360 return (ssize_t)buflen;
361 if (errno != ENOSYS)
362 return -1;
363 }
364 #elif defined(OPENSSL_APPLE_CRYPTO_RANDOM)
365
366 if (CCRandomGenerateBytes(buf, buflen) == kCCSuccess)
367 return (ssize_t)buflen;
368
369 return -1;
370 #else
371 union {
372 void *p;
373 int (*f)(void *buffer, size_t length);
374 } p_getentropy;
375
376 /*
377 * We could cache the result of the lookup, but we normally don't
378 * call this function often.
379 */
380 ERR_set_mark();
381 p_getentropy.p = DSO_global_lookup("getentropy");
382 ERR_pop_to_mark();
383 if (p_getentropy.p != NULL)
384 return p_getentropy.f(buf, buflen) == 0 ? (ssize_t)buflen : -1;
385 #endif
386 #endif /* !__DragonFly__ && !__NetBSD__ && !__FreeBSD__ */
387
388 /* Linux supports this since version 3.17 */
389 #if defined(__linux) && defined(__NR_getrandom)
390 return syscall(__NR_getrandom, buf, buflen, 0);
391 #elif (defined(__DragonFly__) && __DragonFly_version >= 500700) \
392 || (defined(__NetBSD__) && __NetBSD_Version >= 1000000000) \
393 || (defined(__FreeBSD__) && __FreeBSD_version >= 1200061)
394 return getrandom(buf, buflen, 0);
395 #elif (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
396 return sysctl_random(buf, buflen);
397 #elif defined(__wasi__)
398 if (getentropy(buf, buflen) == 0)
399 return (ssize_t)buflen;
400 return -1;
401 #else
402 errno = ENOSYS;
403 return -1;
404 #endif
405 }
406 #endif /* defined(OPENSSL_RAND_SEED_GETRANDOM) */
407
408 #if defined(OPENSSL_RAND_SEED_DEVRANDOM)
409 static const char *random_device_paths[] = { DEVRANDOM };
410 static struct random_device {
411 int fd;
412 dev_t dev;
413 ino_t ino;
414 mode_t mode;
415 dev_t rdev;
416 } random_devices[OSSL_NELEM(random_device_paths)];
417 static int keep_random_devices_open = 1;
418
419 #if defined(__linux) && defined(DEVRANDOM_WAIT) \
420 && defined(OPENSSL_RAND_SEED_GETRANDOM)
421 static void *shm_addr;
422
cleanup_shm(void)423 static void cleanup_shm(void)
424 {
425 shmdt(shm_addr);
426 }
427
428 /*
429 * Ensure that the system randomness source has been adequately seeded.
430 * This is done by having the first start of libcrypto, wait until the device
431 * /dev/random becomes able to supply a byte of entropy. Subsequent starts
432 * of the library and later reseedings do not need to do this.
433 */
wait_random_seeded(void)434 static int wait_random_seeded(void)
435 {
436 static int seeded = OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID < 0;
437 static const int kernel_version[] = { DEVRANDOM_SAFE_KERNEL };
438 int kernel[2];
439 int shm_id, fd, r;
440 char c, *p;
441 struct utsname un;
442 fd_set fds;
443
444 if (!seeded) {
445 /* See if anything has created the global seeded indication */
446 if ((shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1, 0)) == -1) {
447 /*
448 * Check the kernel's version and fail if it is too recent.
449 *
450 * Linux kernels from 4.8 onwards do not guarantee that
451 * /dev/urandom is properly seeded when /dev/random becomes
452 * readable. However, such kernels support the getentropy(2)
453 * system call and this should always succeed which renders
454 * this alternative but essentially identical source moot.
455 */
456 if (uname(&un) == 0) {
457 kernel[0] = atoi(un.release);
458 p = strchr(un.release, '.');
459 kernel[1] = p == NULL ? 0 : atoi(p + 1);
460 if (kernel[0] > kernel_version[0]
461 || (kernel[0] == kernel_version[0]
462 && kernel[1] >= kernel_version[1])) {
463 return 0;
464 }
465 }
466 /* Open /dev/random and wait for it to be readable */
467 if ((fd = open(DEVRANDOM_WAIT, O_RDONLY)) != -1) {
468 if (DEVRANDM_WAIT_USE_SELECT && fd < FD_SETSIZE) {
469 FD_ZERO(&fds);
470 FD_SET(fd, &fds);
471 while ((r = select(fd + 1, &fds, NULL, NULL, NULL)) < 0
472 && errno == EINTR)
473 ;
474 } else {
475 while ((r = read(fd, &c, 1)) < 0 && errno == EINTR)
476 ;
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 */
wait_random_seeded(void)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 */
check_random_device(struct random_device * rd)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 */
get_random_device(size_t n)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 */
close_random_device(size_t n)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
ossl_rand_pool_init(void)568 int ossl_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
ossl_rand_pool_cleanup(void)578 void ossl_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
ossl_rand_pool_keep_random_devices_open(int keep)586 void ossl_rand_pool_keep_random_devices_open(int keep)
587 {
588 if (!keep)
589 ossl_rand_pool_cleanup();
590
591 keep_random_devices_open = keep;
592 }
593
594 #else /* !defined(OPENSSL_RAND_SEED_DEVRANDOM) */
595
ossl_rand_pool_init(void)596 int ossl_rand_pool_init(void)
597 {
598 return 1;
599 }
600
ossl_rand_pool_cleanup(void)601 void ossl_rand_pool_cleanup(void)
602 {
603 }
604
ossl_rand_pool_keep_random_devices_open(int keep)605 void ossl_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 * 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 */
ossl_pool_acquire_entropy(RAND_POOL * pool)628 size_t ossl_pool_acquire_entropy(RAND_POOL *pool)
629 {
630 #if defined(OPENSSL_RAND_SEED_NONE)
631 return ossl_rand_pool_entropy_available(pool);
632 #else
633 size_t entropy_available = 0;
634
635 (void)entropy_available; /* avoid compiler warning */
636
637 #if defined(OPENSSL_RAND_SEED_GETRANDOM)
638 {
639 size_t bytes_needed;
640 unsigned char *buffer;
641 ssize_t bytes;
642 /* Maximum allowed number of consecutive unsuccessful attempts */
643 int attempts = 3;
644
645 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
646 while (bytes_needed != 0 && attempts-- > 0) {
647 buffer = ossl_rand_pool_add_begin(pool, bytes_needed);
648 bytes = syscall_random(buffer, bytes_needed);
649 if (bytes > 0) {
650 ossl_rand_pool_add_end(pool, bytes, 8 * bytes);
651 bytes_needed -= bytes;
652 attempts = 3; /* reset counter after successful attempt */
653 } else if (bytes < 0 && errno != EINTR) {
654 break;
655 }
656 }
657 }
658 entropy_available = ossl_rand_pool_entropy_available(pool);
659 if (entropy_available > 0)
660 return entropy_available;
661 #endif
662
663 #if defined(OPENSSL_RAND_SEED_DEVRANDOM)
664 if (wait_random_seeded()) {
665 size_t bytes_needed;
666 unsigned char *buffer;
667 size_t i;
668
669 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
670 for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths);
671 i++) {
672 ssize_t bytes = 0;
673 /* Maximum number of consecutive unsuccessful attempts */
674 int attempts = 3;
675 const int fd = get_random_device(i);
676
677 if (fd == -1)
678 continue;
679
680 while (bytes_needed != 0 && attempts-- > 0) {
681 buffer = ossl_rand_pool_add_begin(pool, bytes_needed);
682 bytes = read(fd, buffer, bytes_needed);
683
684 if (bytes > 0) {
685 ossl_rand_pool_add_end(pool, bytes, 8 * bytes);
686 bytes_needed -= bytes;
687 attempts = 3; /* reset counter on successful attempt */
688 } else if (bytes < 0 && errno != EINTR) {
689 break;
690 }
691 }
692 if (bytes < 0 || !keep_random_devices_open)
693 close_random_device(i);
694
695 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1);
696 }
697 entropy_available = ossl_rand_pool_entropy_available(pool);
698 if (entropy_available > 0)
699 return entropy_available;
700 }
701 #endif
702
703 #if defined(OPENSSL_RAND_SEED_RDTSC)
704 entropy_available = ossl_prov_acquire_entropy_from_tsc(pool);
705 if (entropy_available > 0)
706 return entropy_available;
707 #endif
708
709 #if defined(OPENSSL_RAND_SEED_RDCPU)
710 entropy_available = ossl_prov_acquire_entropy_from_cpu(pool);
711 if (entropy_available > 0)
712 return entropy_available;
713 #endif
714
715 #if defined(OPENSSL_RAND_SEED_EGD)
716 {
717 static const char *paths[] = { DEVRANDOM_EGD, NULL };
718 size_t bytes_needed;
719 unsigned char *buffer;
720 int i;
721
722 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
723 for (i = 0; bytes_needed > 0 && paths[i] != NULL; i++) {
724 size_t bytes = 0;
725 int num;
726
727 buffer = ossl_rand_pool_add_begin(pool, bytes_needed);
728 num = RAND_query_egd_bytes(paths[i],
729 buffer, (int)bytes_needed);
730 if (num == (int)bytes_needed)
731 bytes = bytes_needed;
732
733 ossl_rand_pool_add_end(pool, bytes, 8 * bytes);
734 bytes_needed = ossl_rand_pool_bytes_needed(pool, 1);
735 }
736 entropy_available = ossl_rand_pool_entropy_available(pool);
737 if (entropy_available > 0)
738 return entropy_available;
739 }
740 #endif
741
742 return ossl_rand_pool_entropy_available(pool);
743 #endif
744 }
745 #endif
746 #endif
747
748 #if (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS)) \
749 || defined(__DJGPP__)
ossl_pool_add_nonce_data(RAND_POOL * pool)750 int ossl_pool_add_nonce_data(RAND_POOL *pool)
751 {
752 struct {
753 pid_t pid;
754 CRYPTO_THREAD_ID tid;
755 uint64_t time;
756 } data;
757
758 /* Erase the entire structure including any padding */
759 memset(&data, 0, sizeof(data));
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 ossl_rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
771 }
772
773 /*
774 * Get the current time with the highest possible resolution
775 *
776 * The time stamp is added to the nonce, so it is optimized for not repeating.
777 * The current time is ideal for this purpose, provided the computer's clock
778 * is synchronized.
779 */
get_time_stamp(void)780 static uint64_t get_time_stamp(void)
781 {
782 #if defined(OSSL_POSIX_TIMER_OKAY)
783 {
784 struct timespec ts;
785
786 if (clock_gettime(CLOCK_REALTIME, &ts) == 0)
787 return TWO32TO64(ts.tv_sec, ts.tv_nsec);
788 }
789 #endif
790 #if defined(__unix__) \
791 || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
792 {
793 struct timeval tv;
794
795 if (gettimeofday(&tv, NULL) == 0)
796 return TWO32TO64(tv.tv_sec, tv.tv_usec);
797 }
798 #endif
799 return time(NULL);
800 }
801
802 #endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS)) \
803 || defined(__DJGPP__) */
804