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openssl/crypto/rand/rand_unix.c

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v1.1.1t
2023-05-09 22:08:48 +00:00
/*
* Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#ifndef _GNU_SOURCE
# define _GNU_SOURCE
#endif
#include "e_os.h"
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/rand.h>
#include <openssl/crypto.h>
#include "rand_local.h"
#include "crypto/rand.h"
#include <stdio.h>
#include "internal/dso.h"
#ifdef __linux
# include <sys/syscall.h>
# ifdef DEVRANDOM_WAIT
# include <sys/shm.h>
# include <sys/utsname.h>
# endif
#endif
#if (defined(__FreeBSD__) || defined(__NetBSD__)) && !defined(OPENSSL_SYS_UEFI)
# include <sys/types.h>
# include <sys/sysctl.h>
# include <sys/param.h>
#endif
#if defined(__OpenBSD__)
# include <sys/param.h>
#endif
#if defined(OPENSSL_SYS_UNIX) || defined(__DJGPP__)
# include <sys/types.h>
# include <sys/stat.h>
# include <fcntl.h>
# include <unistd.h>
# include <sys/time.h>
static uint64_t get_time_stamp(void);
static uint64_t get_timer_bits(void);
/* Macro to convert two thirty two bit values into a sixty four bit one */
# define TWO32TO64(a, b) ((((uint64_t)(a)) << 32) + (b))
/*
* Check for the existence and support of POSIX timers. The standard
* says that the _POSIX_TIMERS macro will have a positive value if they
* are available.
*
* However, we want an additional constraint: that the timer support does
* not require an extra library dependency. Early versions of glibc
* require -lrt to be specified on the link line to access the timers,
* so this needs to be checked for.
*
* It is worse because some libraries define __GLIBC__ but don't
* support the version testing macro (e.g. uClibc). This means
* an extra check is needed.
*
* The final condition is:
* "have posix timers and either not glibc or glibc without -lrt"
*
* The nested #if sequences are required to avoid using a parameterised
* macro that might be undefined.
*/
# undef OSSL_POSIX_TIMER_OKAY
# if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
# if defined(__GLIBC__)
# if defined(__GLIBC_PREREQ)
# if __GLIBC_PREREQ(2, 17)
# define OSSL_POSIX_TIMER_OKAY
# endif
# endif
# else
# define OSSL_POSIX_TIMER_OKAY
# endif
# endif
#endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS))
|| defined(__DJGPP__) */
#if defined(OPENSSL_RAND_SEED_NONE)
/* none means none. this simplifies the following logic */
# undef OPENSSL_RAND_SEED_OS
# undef OPENSSL_RAND_SEED_GETRANDOM
# undef OPENSSL_RAND_SEED_LIBRANDOM
# undef OPENSSL_RAND_SEED_DEVRANDOM
# undef OPENSSL_RAND_SEED_RDTSC
# undef OPENSSL_RAND_SEED_RDCPU
# undef OPENSSL_RAND_SEED_EGD
#endif
#if (defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI)) && \
!defined(OPENSSL_RAND_SEED_NONE)
# error "UEFI and VXWorks only support seeding NONE"
#endif
#if defined(OPENSSL_SYS_VXWORKS)
/* empty implementation */
int rand_pool_init(void)
{
return 1;
}
void rand_pool_cleanup(void)
{
}
void rand_pool_keep_random_devices_open(int keep)
{
}
size_t rand_pool_acquire_entropy(RAND_POOL *pool)
{
return rand_pool_entropy_available(pool);
}
#endif
#if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) \
|| defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) \
|| defined(OPENSSL_SYS_UEFI))
# if defined(OPENSSL_SYS_VOS)
# ifndef OPENSSL_RAND_SEED_OS
# error "Unsupported seeding method configured; must be os"
# endif
# if defined(OPENSSL_SYS_VOS_HPPA) && defined(OPENSSL_SYS_VOS_IA32)
# error "Unsupported HP-PA and IA32 at the same time."
# endif
# if !defined(OPENSSL_SYS_VOS_HPPA) && !defined(OPENSSL_SYS_VOS_IA32)
# error "Must have one of HP-PA or IA32"
# endif
/*
* The following algorithm repeatedly samples the real-time clock (RTC) to
* generate a sequence of unpredictable data. The algorithm relies upon the
* uneven execution speed of the code (due to factors such as cache misses,
* interrupts, bus activity, and scheduling) and upon the rather large
* relative difference between the speed of the clock and the rate at which
* it can be read. If it is ported to an environment where execution speed
* is more constant or where the RTC ticks at a much slower rate, or the
* clock can be read with fewer instructions, it is likely that the results
* would be far more predictable. This should only be used for legacy
* platforms.
*
* As a precaution, we assume only 2 bits of entropy per byte.
*/
size_t rand_pool_acquire_entropy(RAND_POOL *pool)
{
short int code;
int i, k;
size_t bytes_needed;
struct timespec ts;
unsigned char v;
# ifdef OPENSSL_SYS_VOS_HPPA
long duration;
extern void s$sleep(long *_duration, short int *_code);
# else
long long duration;
extern void s$sleep2(long long *_duration, short int *_code);
# endif
bytes_needed = rand_pool_bytes_needed(pool, 4 /*entropy_factor*/);
for (i = 0; i < bytes_needed; i++) {
/*
* burn some cpu; hope for interrupts, cache collisions, bus
* interference, etc.
*/
for (k = 0; k < 99; k++)
ts.tv_nsec = random();
# ifdef OPENSSL_SYS_VOS_HPPA
/* sleep for 1/1024 of a second (976 us). */
duration = 1;
s$sleep(&duration, &code);
# else
/* sleep for 1/65536 of a second (15 us). */
duration = 1;
s$sleep2(&duration, &code);
# endif
/* Get wall clock time, take 8 bits. */
clock_gettime(CLOCK_REALTIME, &ts);
v = (unsigned char)(ts.tv_nsec & 0xFF);
rand_pool_add(pool, arg, &v, sizeof(v) , 2);
}
return rand_pool_entropy_available(pool);
}
void rand_pool_cleanup(void)
{
}
void rand_pool_keep_random_devices_open(int keep)
{
}
# else
# if defined(OPENSSL_RAND_SEED_EGD) && \
(defined(OPENSSL_NO_EGD) || !defined(DEVRANDOM_EGD))
# error "Seeding uses EGD but EGD is turned off or no device given"
# endif
# if defined(OPENSSL_RAND_SEED_DEVRANDOM) && !defined(DEVRANDOM)
# error "Seeding uses urandom but DEVRANDOM is not configured"
# endif
# if defined(OPENSSL_RAND_SEED_OS)
# if !defined(DEVRANDOM)
# error "OS seeding requires DEVRANDOM to be configured"
# endif
# define OPENSSL_RAND_SEED_GETRANDOM
# define OPENSSL_RAND_SEED_DEVRANDOM
# endif
# if defined(OPENSSL_RAND_SEED_LIBRANDOM)
# error "librandom not (yet) supported"
# endif
# if (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
/*
* sysctl_random(): Use sysctl() to read a random number from the kernel
* Returns the number of bytes returned in buf on success, -1 on failure.
*/
static ssize_t sysctl_random(char *buf, size_t buflen)
{
int mib[2];
size_t done = 0;
size_t len;
/*
* Note: sign conversion between size_t and ssize_t is safe even
* without a range check, see comment in syscall_random()
*/
/*
* On FreeBSD old implementations returned longs, newer versions support
* variable sizes up to 256 byte. The code below would not work properly
* when the sysctl returns long and we want to request something not a
* multiple of longs, which should never be the case.
*/
#if defined(__FreeBSD__)
if (!ossl_assert(buflen % sizeof(long) == 0)) {
errno = EINVAL;
return -1;
}
#endif
/*
* On NetBSD before 4.0 KERN_ARND was an alias for KERN_URND, and only
* filled in an int, leaving the rest uninitialized. Since NetBSD 4.0
* it returns a variable number of bytes with the current version supporting
* up to 256 bytes.
* Just return an error on older NetBSD versions.
*/
#if defined(__NetBSD__) && __NetBSD_Version__ < 400000000
errno = ENOSYS;
return -1;
#endif
mib[0] = CTL_KERN;
mib[1] = KERN_ARND;
do {
len = buflen > 256 ? 256 : buflen;
if (sysctl(mib, 2, buf, &len, NULL, 0) == -1)
return done > 0 ? done : -1;
done += len;
buf += len;
buflen -= len;
} while (buflen > 0);
return done;
}
# endif
# if defined(OPENSSL_RAND_SEED_GETRANDOM)
# if defined(__linux) && !defined(__NR_getrandom)
# if defined(__arm__)
# define __NR_getrandom (__NR_SYSCALL_BASE+384)
# elif defined(__i386__)
# define __NR_getrandom 355
# elif defined(__x86_64__)
# if defined(__ILP32__)
# define __NR_getrandom (__X32_SYSCALL_BIT + 318)
# else
# define __NR_getrandom 318
# endif
# elif defined(__xtensa__)
# define __NR_getrandom 338
# elif defined(__s390__) || defined(__s390x__)
# define __NR_getrandom 349
# elif defined(__bfin__)
# define __NR_getrandom 389
# elif defined(__powerpc__)
# define __NR_getrandom 359
# elif defined(__mips__) || defined(__mips64)
# if _MIPS_SIM == _MIPS_SIM_ABI32
# define __NR_getrandom (__NR_Linux + 353)
# elif _MIPS_SIM == _MIPS_SIM_ABI64
# define __NR_getrandom (__NR_Linux + 313)
# elif _MIPS_SIM == _MIPS_SIM_NABI32
# define __NR_getrandom (__NR_Linux + 317)
# endif
# elif defined(__hppa__)
# define __NR_getrandom (__NR_Linux + 339)
# elif defined(__sparc__)
# define __NR_getrandom 347
# elif defined(__ia64__)
# define __NR_getrandom 1339
# elif defined(__alpha__)
# define __NR_getrandom 511
# elif defined(__sh__)
# if defined(__SH5__)
# define __NR_getrandom 373
# else
# define __NR_getrandom 384
# endif
# elif defined(__avr32__)
# define __NR_getrandom 317
# elif defined(__microblaze__)
# define __NR_getrandom 385
# elif defined(__m68k__)
# define __NR_getrandom 352
# elif defined(__cris__)
# define __NR_getrandom 356
# elif defined(__aarch64__)
# define __NR_getrandom 278
# else /* generic */
# define __NR_getrandom 278
# endif
# endif
/*
* syscall_random(): Try to get random data using a system call
* returns the number of bytes returned in buf, or < 0 on error.
*/
static ssize_t syscall_random(void *buf, size_t buflen)
{
/*
* Note: 'buflen' equals the size of the buffer which is used by the
* get_entropy() callback of the RAND_DRBG. It is roughly bounded by
*
* 2 * RAND_POOL_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^14
*
* which is way below the OSSL_SSIZE_MAX limit. Therefore sign conversion
* between size_t and ssize_t is safe even without a range check.
*/
/*
* Do runtime detection to find getentropy().
*
* Known OSs that should support this:
* - Darwin since 16 (OSX 10.12, IOS 10.0).
* - Solaris since 11.3
* - OpenBSD since 5.6
* - Linux since 3.17 with glibc 2.25
* - FreeBSD since 12.0 (1200061)
*
* Note: Sometimes getentropy() can be provided but not implemented
* internally. So we need to check errno for ENOSYS
*/
# if defined(__GNUC__) && __GNUC__>=2 && defined(__ELF__) && !defined(__hpux)
extern int getentropy(void *buffer, size_t length) __attribute__((weak));
if (getentropy != NULL) {
if (getentropy(buf, buflen) == 0)
return (ssize_t)buflen;
if (errno != ENOSYS)
return -1;
}
# elif defined(OPENSSL_APPLE_CRYPTO_RANDOM)
if (CCRandomGenerateBytes(buf, buflen) == kCCSuccess)
return (ssize_t)buflen;
return -1;
# else
union {
void *p;
int (*f)(void *buffer, size_t length);
} p_getentropy;
/*
* We could cache the result of the lookup, but we normally don't
* call this function often.
*/
ERR_set_mark();
p_getentropy.p = DSO_global_lookup("getentropy");
ERR_pop_to_mark();
if (p_getentropy.p != NULL)
return p_getentropy.f(buf, buflen) == 0 ? (ssize_t)buflen : -1;
# endif
/* Linux supports this since version 3.17 */
# if defined(__linux) && defined(__NR_getrandom)
return syscall(__NR_getrandom, buf, buflen, 0);
# elif (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
return sysctl_random(buf, buflen);
# else
errno = ENOSYS;
return -1;
# endif
}
# endif /* defined(OPENSSL_RAND_SEED_GETRANDOM) */
# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
static const char *random_device_paths[] = { DEVRANDOM };
static struct random_device {
int fd;
dev_t dev;
ino_t ino;
mode_t mode;
dev_t rdev;
} random_devices[OSSL_NELEM(random_device_paths)];
static int keep_random_devices_open = 1;
# if defined(__linux) && defined(DEVRANDOM_WAIT) \
&& defined(OPENSSL_RAND_SEED_GETRANDOM)
static void *shm_addr;
static void cleanup_shm(void)
{
shmdt(shm_addr);
}
/*
* Ensure that the system randomness source has been adequately seeded.
* This is done by having the first start of libcrypto, wait until the device
* /dev/random becomes able to supply a byte of entropy. Subsequent starts
* of the library and later reseedings do not need to do this.
*/
static int wait_random_seeded(void)
{
static int seeded = OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID < 0;
static const int kernel_version[] = { DEVRANDOM_SAFE_KERNEL };
int kernel[2];
int shm_id, fd, r;
char c, *p;
struct utsname un;
fd_set fds;
if (!seeded) {
/* See if anything has created the global seeded indication */
if ((shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1, 0)) == -1) {
/*
* Check the kernel's version and fail if it is too recent.
*
* Linux kernels from 4.8 onwards do not guarantee that
* /dev/urandom is properly seeded when /dev/random becomes
* readable. However, such kernels support the getentropy(2)
* system call and this should always succeed which renders
* this alternative but essentially identical source moot.
*/
if (uname(&un) == 0) {
kernel[0] = atoi(un.release);
p = strchr(un.release, '.');
kernel[1] = p == NULL ? 0 : atoi(p + 1);
if (kernel[0] > kernel_version[0]
|| (kernel[0] == kernel_version[0]
&& kernel[1] >= kernel_version[1])) {
return 0;
}
}
/* Open /dev/random and wait for it to be readable */
if ((fd = open(DEVRANDOM_WAIT, O_RDONLY)) != -1) {
if (DEVRANDM_WAIT_USE_SELECT && fd < FD_SETSIZE) {
FD_ZERO(&fds);
FD_SET(fd, &fds);
while ((r = select(fd + 1, &fds, NULL, NULL, NULL)) < 0
&& errno == EINTR);
} else {
while ((r = read(fd, &c, 1)) < 0 && errno == EINTR);
}
close(fd);
if (r == 1) {
seeded = 1;
/* Create the shared memory indicator */
shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1,
IPC_CREAT | S_IRUSR | S_IRGRP | S_IROTH);
}
}
}
if (shm_id != -1) {
seeded = 1;
/*
* Map the shared memory to prevent its premature destruction.
* If this call fails, it isn't a big problem.
*/
shm_addr = shmat(shm_id, NULL, SHM_RDONLY);
if (shm_addr != (void *)-1)
OPENSSL_atexit(&cleanup_shm);
}
}
return seeded;
}
# else /* defined __linux && DEVRANDOM_WAIT && OPENSSL_RAND_SEED_GETRANDOM */
static int wait_random_seeded(void)
{
return 1;
}
# endif
/*
* Verify that the file descriptor associated with the random source is
* still valid. The rationale for doing this is the fact that it is not
* uncommon for daemons to close all open file handles when daemonizing.
* So the handle might have been closed or even reused for opening
* another file.
*/
static int check_random_device(struct random_device * rd)
{
struct stat st;
return rd->fd != -1
&& fstat(rd->fd, &st) != -1
&& rd->dev == st.st_dev
&& rd->ino == st.st_ino
&& ((rd->mode ^ st.st_mode) & ~(S_IRWXU | S_IRWXG | S_IRWXO)) == 0
&& rd->rdev == st.st_rdev;
}
/*
* Open a random device if required and return its file descriptor or -1 on error
*/
static int get_random_device(size_t n)
{
struct stat st;
struct random_device * rd = &random_devices[n];
/* reuse existing file descriptor if it is (still) valid */
if (check_random_device(rd))
return rd->fd;
/* open the random device ... */
if ((rd->fd = open(random_device_paths[n], O_RDONLY)) == -1)
return rd->fd;
/* ... and cache its relevant stat(2) data */
if (fstat(rd->fd, &st) != -1) {
rd->dev = st.st_dev;
rd->ino = st.st_ino;
rd->mode = st.st_mode;
rd->rdev = st.st_rdev;
} else {
close(rd->fd);
rd->fd = -1;
}
return rd->fd;
}
/*
* Close a random device making sure it is a random device
*/
static void close_random_device(size_t n)
{
struct random_device * rd = &random_devices[n];
if (check_random_device(rd))
close(rd->fd);
rd->fd = -1;
}
int rand_pool_init(void)
{
size_t i;
for (i = 0; i < OSSL_NELEM(random_devices); i++)
random_devices[i].fd = -1;
return 1;
}
void rand_pool_cleanup(void)
{
size_t i;
for (i = 0; i < OSSL_NELEM(random_devices); i++)
close_random_device(i);
}
void rand_pool_keep_random_devices_open(int keep)
{
if (!keep)
rand_pool_cleanup();
keep_random_devices_open = keep;
}
# else /* !defined(OPENSSL_RAND_SEED_DEVRANDOM) */
int rand_pool_init(void)
{
return 1;
}
void rand_pool_cleanup(void)
{
}
void rand_pool_keep_random_devices_open(int keep)
{
}
# endif /* defined(OPENSSL_RAND_SEED_DEVRANDOM) */
/*
* Try the various seeding methods in turn, exit when successful.
*
* TODO(DRBG): If more than one entropy source is available, is it
* preferable to stop as soon as enough entropy has been collected
* (as favored by @rsalz) or should one rather be defensive and add
* more entropy than requested and/or from different sources?
*
* Currently, the user can select multiple entropy sources in the
* configure step, yet in practice only the first available source
* will be used. A more flexible solution has been requested, but
* currently it is not clear how this can be achieved without
* overengineering the problem. There are many parameters which
* could be taken into account when selecting the order and amount
* of input from the different entropy sources (trust, quality,
* possibility of blocking).
*/
size_t rand_pool_acquire_entropy(RAND_POOL *pool)
{
# if defined(OPENSSL_RAND_SEED_NONE)
return rand_pool_entropy_available(pool);
# else
size_t entropy_available;
# if defined(OPENSSL_RAND_SEED_GETRANDOM)
{
size_t bytes_needed;
unsigned char *buffer;
ssize_t bytes;
/* Maximum allowed number of consecutive unsuccessful attempts */
int attempts = 3;
bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
while (bytes_needed != 0 && attempts-- > 0) {
buffer = rand_pool_add_begin(pool, bytes_needed);
bytes = syscall_random(buffer, bytes_needed);
if (bytes > 0) {
rand_pool_add_end(pool, bytes, 8 * bytes);
bytes_needed -= bytes;
attempts = 3; /* reset counter after successful attempt */
} else if (bytes < 0 && errno != EINTR) {
break;
}
}
}
entropy_available = rand_pool_entropy_available(pool);
if (entropy_available > 0)
return entropy_available;
# endif
# if defined(OPENSSL_RAND_SEED_LIBRANDOM)
{
/* Not yet implemented. */
}
# endif
# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
if (wait_random_seeded()) {
size_t bytes_needed;
unsigned char *buffer;
size_t i;
bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths);
i++) {
ssize_t bytes = 0;
/* Maximum number of consecutive unsuccessful attempts */
int attempts = 3;
const int fd = get_random_device(i);
if (fd == -1)
continue;
while (bytes_needed != 0 && attempts-- > 0) {
buffer = rand_pool_add_begin(pool, bytes_needed);
bytes = read(fd, buffer, bytes_needed);
if (bytes > 0) {
rand_pool_add_end(pool, bytes, 8 * bytes);
bytes_needed -= bytes;
attempts = 3; /* reset counter on successful attempt */
} else if (bytes < 0 && errno != EINTR) {
break;
}
}
if (bytes < 0 || !keep_random_devices_open)
close_random_device(i);
bytes_needed = rand_pool_bytes_needed(pool, 1);
}
entropy_available = rand_pool_entropy_available(pool);
if (entropy_available > 0)
return entropy_available;
}
# endif
# if defined(OPENSSL_RAND_SEED_RDTSC)
entropy_available = rand_acquire_entropy_from_tsc(pool);
if (entropy_available > 0)
return entropy_available;
# endif
# if defined(OPENSSL_RAND_SEED_RDCPU)
entropy_available = rand_acquire_entropy_from_cpu(pool);
if (entropy_available > 0)
return entropy_available;
# endif
# if defined(OPENSSL_RAND_SEED_EGD)
{
static const char *paths[] = { DEVRANDOM_EGD, NULL };
size_t bytes_needed;
unsigned char *buffer;
int i;
bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
for (i = 0; bytes_needed > 0 && paths[i] != NULL; i++) {
size_t bytes = 0;
int num;
buffer = rand_pool_add_begin(pool, bytes_needed);
num = RAND_query_egd_bytes(paths[i],
buffer, (int)bytes_needed);
if (num == (int)bytes_needed)
bytes = bytes_needed;
rand_pool_add_end(pool, bytes, 8 * bytes);
bytes_needed = rand_pool_bytes_needed(pool, 1);
}
entropy_available = rand_pool_entropy_available(pool);
if (entropy_available > 0)
return entropy_available;
}
# endif
return rand_pool_entropy_available(pool);
# endif
}
# endif
#endif
#if defined(OPENSSL_SYS_UNIX) || defined(__DJGPP__)
int rand_pool_add_nonce_data(RAND_POOL *pool)
{
struct {
pid_t pid;
CRYPTO_THREAD_ID tid;
uint64_t time;
} data = { 0 };
/*
* Add process id, thread id, and a high resolution timestamp to
* ensure that the nonce is unique with high probability for
* different process instances.
*/
data.pid = getpid();
data.tid = CRYPTO_THREAD_get_current_id();
data.time = get_time_stamp();
return rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
}
int rand_pool_add_additional_data(RAND_POOL *pool)
{
struct {
int fork_id;
CRYPTO_THREAD_ID tid;
uint64_t time;
} data = { 0 };
/*
* Add some noise from the thread id and a high resolution timer.
* The fork_id adds some extra fork-safety.
* The thread id adds a little randomness if the drbg is accessed
* concurrently (which is the case for the <master> drbg).
*/
data.fork_id = openssl_get_fork_id();
data.tid = CRYPTO_THREAD_get_current_id();
data.time = get_timer_bits();
return rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
}
/*
* Get the current time with the highest possible resolution
*
* The time stamp is added to the nonce, so it is optimized for not repeating.
* The current time is ideal for this purpose, provided the computer's clock
* is synchronized.
*/
static uint64_t get_time_stamp(void)
{
# if defined(OSSL_POSIX_TIMER_OKAY)
{
struct timespec ts;
if (clock_gettime(CLOCK_REALTIME, &ts) == 0)
return TWO32TO64(ts.tv_sec, ts.tv_nsec);
}
# endif
# if defined(__unix__) \
|| (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
{
struct timeval tv;
if (gettimeofday(&tv, NULL) == 0)
return TWO32TO64(tv.tv_sec, tv.tv_usec);
}
# endif
return time(NULL);
}
/*
* Get an arbitrary timer value of the highest possible resolution
*
* The timer value is added as random noise to the additional data,
* which is not considered a trusted entropy sourec, so any result
* is acceptable.
*/
static uint64_t get_timer_bits(void)
{
uint64_t res = OPENSSL_rdtsc();
if (res != 0)
return res;
# if defined(__sun) || defined(__hpux)
return gethrtime();
# elif defined(_AIX)
{
timebasestruct_t t;
read_wall_time(&t, TIMEBASE_SZ);
return TWO32TO64(t.tb_high, t.tb_low);
}
# elif defined(OSSL_POSIX_TIMER_OKAY)
{
struct timespec ts;
# ifdef CLOCK_BOOTTIME
# define CLOCK_TYPE CLOCK_BOOTTIME
# elif defined(_POSIX_MONOTONIC_CLOCK)
# define CLOCK_TYPE CLOCK_MONOTONIC
# else
# define CLOCK_TYPE CLOCK_REALTIME
# endif
if (clock_gettime(CLOCK_TYPE, &ts) == 0)
return TWO32TO64(ts.tv_sec, ts.tv_nsec);
}
# endif
# if defined(__unix__) \
|| (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
{
struct timeval tv;
if (gettimeofday(&tv, NULL) == 0)
return TWO32TO64(tv.tv_sec, tv.tv_usec);
}
# endif
return time(NULL);
}
#endif /* (defined(OPENSSL_SYS_UNIX) && !defined(OPENSSL_SYS_VXWORKS))
|| defined(__DJGPP__) */