Commit 2b66fd57 authored by Pauli's avatar Pauli
Browse files

Unify timer code 



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: default avatarRichard Levitte <levitte@openssl.org>
Reviewed-by: default avatarMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/5231)
parent 360fc9f4

crypto/rand/rand_lib.c

+71 −21
Original line number Diff line number Diff line
@@ -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? */