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 */
rand_pool_init(void)104 int rand_pool_init(void)
105 {
106 return 1;
107 }
108
rand_pool_cleanup(void)109 void rand_pool_cleanup(void)
110 {
111 }
112
rand_pool_keep_random_devices_open(int keep)113 void rand_pool_keep_random_devices_open(int keep)
114 {
115 }
116
rand_pool_acquire_entropy(RAND_POOL * pool)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 */
rand_pool_acquire_entropy(RAND_POOL * pool)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
rand_pool_cleanup(void)197 void rand_pool_cleanup(void)
198 {
199 }
200
rand_pool_keep_random_devices_open(int keep)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 */
sysctl_random(char * buf,size_t buflen)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 */
syscall_random(void * buf,size_t buflen)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
cleanup_shm(void)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 */
wait_random_seeded(void)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 */
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
rand_pool_init(void)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
rand_pool_cleanup(void)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
rand_pool_keep_random_devices_open(int keep)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
rand_pool_init(void)596 int rand_pool_init(void)
597 {
598 return 1;
599 }
600
rand_pool_cleanup(void)601 void rand_pool_cleanup(void)
602 {
603 }
604
rand_pool_keep_random_devices_open(int keep)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 */
rand_pool_acquire_entropy(RAND_POOL * pool)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__)
rand_pool_add_nonce_data(RAND_POOL * pool)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
rand_pool_add_additional_data(RAND_POOL * pool)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 */
get_time_stamp(void)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 */
get_timer_bits(void)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__) */
876