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Impropper initialization of RNG on Windows #8

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Impropper initialization of RNG on Windows #8

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7fa2d49
On Windows platform when using GNU ZRTP library in standalone, without
fedor-brunner Sep 16, 2013
544b771
The build in random number generator is not properly seeded on the
fedor-brunner Sep 20, 2013
23f823b
Merge branch 'compiler_error'
fedor-brunner Sep 20, 2013
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26 changes: 26 additions & 0 deletions cryptcommon/ZrtpRandom.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
*/

#include <fcntl.h>
#include <time.h>

#include <cryptcommon/ZrtpRandom.h>
#include <cryptcommon/aescpp.h>
Expand Down Expand Up @@ -128,6 +129,29 @@ void ZrtpRandom::initialize() {

sha512_begin(&mainCtx);
initialized = true;

// Use the processor time consumed by the program and the
// current time for additional entropy
clock_t clock1 = clock();
time_t time1 = time(NULL);
sha512_hash((unsigned char*)&clock1, sizeof(clock1), &mainCtx);
sha512_hash((unsigned char*)&time1, sizeof(time1), &mainCtx);
#if defined(_WIN32) || defined(_WIN64)
// On Windows the /dev/urandom is not used so additional
// entropy has to be gathered from timers. The run time
// of this loop should be not deterministic, because
// it depends on CPU frequency, cache status, context
// switching speed.
// It runs under 1 second.
clock_t clock2;
time_t time2;
do {
clock2 = clock();
time2 = time(NULL);
sha512_hash((unsigned char*)&clock2, sizeof(clock2), &mainCtx);
sha512_hash((unsigned char*)&time2, sizeof(time2), &mainCtx);
} while (clock1 == clock1 && time1 == time2);
#endif
}

/*
Expand All @@ -148,6 +172,8 @@ size_t ZrtpRandom::getSystemSeed(uint8_t *seed, size_t length)
}
else
return num;
#else
#error This random number generator can not be used on Windows platform without seeding!
#endif
return num;
}
Expand Down