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Unify timer code

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Remove the timer and TSC additional input code and instead provide a single
routine that attempts to use the "best" timer/counter available on the
system.  It attempts to use TSC, then various OS dependent resources and
finally several tries to obtain the date.  If any of these timer/counters
is successful, the rest are skipped.

No randomness is credited for this.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/5231)
This commit is contained in:
Pauli 2018-02-06 07:17:31 +10:00
parent 360fc9f412
commit 2b66fd5720
1 changed files with 71 additions and 21 deletions
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92
crypto/rand/rand_lib.c
View file

@ -22,6 +22,9 @@
#endif
#include "e_os.h"
/* Macro to convert two thirty two bit values into a sixty four bit one */
#define TWO32TO64(a, b) ((((uint64_t)(a)) << 32) + (b))
#ifndef OPENSSL_NO_ENGINE
/* non-NULL if default_RAND_meth is ENGINE-provided */
static ENGINE *funct_ref;
@ -193,6 +196,71 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
return ret;
}
/*
* Find a suitable system time. Start with the highest resolution source
* and work down to the slower ones. This is added as additional data and
* isn't counted as randomness, so any result is acceptable.
*/
static uint64_t get_timer_bits(void)
{
uint64_t res = OPENSSL_rdtsc();
if (res != 0)
return res;
#if defined(_WIN32)
{
LARGE_INTEGER t;
FILETIME ft;
if (QueryPerformanceCounter(&t) != 0)
return t.QuadPart;
GetSystemTimeAsFileTime(&ft);
return TWO32TO64(ft.dwHighDateTime, ft.dwLowDateTime);
}
#elif 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);
}
#else
# if defined(_POSIX_C_SOURCE) \
&& defined(_POSIX_TIMERS) \
&& _POSIX_C_SOURCE >= 199309L \
&& (!defined(__GLIBC__) || __GLIBC_PREREQ(2, 17))
{
struct timespec ts;
clockid_t cid;
# ifdef CLOCK_BOOTTIME
cid = CLOCK_BOOTTIME;
# elif defined(_POSIX_MONOTONIC_CLOCK)
cid = CLOCK_MONOTONIC;
# else
cid = CLOCK_REALTIME;
# endif
if (clock_gettime(cid, &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
}
/*
* Generate additional data that can be used for the drbg. The data does
* not need to contain entropy, but it's useful if it contains at least
@ -210,15 +278,10 @@ size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len)
size_t len;
#ifdef OPENSSL_SYS_UNIX
pid_t pid;
struct timeval tv;
#elif defined(OPENSSL_SYS_WIN32)
DWORD pid;
FILETIME ft;
LARGE_INTEGER pc;
#endif
#ifdef OPENSSL_CPUID_OBJ
uint32_t tsc = 0;
#endif
uint64_t tbits;
pool = RAND_POOL_new(0, 0, max_len);
if (pool == NULL)
@ -236,21 +299,8 @@ size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len)
if (thread_id != 0)
RAND_POOL_add(pool, (unsigned char *)&thread_id, sizeof(thread_id), 0);
#ifdef OPENSSL_CPUID_OBJ
tsc = OPENSSL_rdtsc();
if (tsc != 0)
RAND_POOL_add(pool, (unsigned char *)&tsc, sizeof(tsc), 0);
#endif
#ifdef OPENSSL_SYS_UNIX
if (gettimeofday(&tv, NULL) == 0)
RAND_POOL_add(pool, (unsigned char *)&tv, sizeof(tv), 0);
#elif defined(OPENSSL_SYS_WIN32)
if (QueryPerformanceCounter(&pc) != 0)
RAND_POOL_add(pool, (unsigned char *)&pc, sizeof(pc), 0);
GetSystemTimeAsFileTime(&ft);
RAND_POOL_add(pool, (unsigned char *)&ft, sizeof(ft), 0);
#endif
tbits = get_timer_bits();
RAND_POOL_add(pool, (unsigned char *)&tbits, sizeof(tbits), 0);
/* TODO: Use RDSEED? */