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50 lines
1.1 KiB
C++
50 lines
1.1 KiB
C++
#include <qpdf/InsecureRandomDataProvider.hh>
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#include <qpdf/QUtil.hh>
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#include <qpdf/qpdf-config.h>
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#include <cstdlib>
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InsecureRandomDataProvider::InsecureRandomDataProvider() :
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seeded_random(false)
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{
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}
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void
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InsecureRandomDataProvider::provideRandomData(unsigned char* data, size_t len)
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{
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for (size_t i = 0; i < len; ++i) {
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data[i] = static_cast<unsigned char>((this->random() & 0xff0) >> 4);
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}
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}
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long
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InsecureRandomDataProvider::random()
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{
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if (!this->seeded_random) {
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// Seed the random number generator with something simple, but
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// just to be interesting, don't use the unmodified current
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// time. It would be better if this were a more secure seed.
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auto seed =
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static_cast<unsigned int>(QUtil::get_current_time() ^ 0xcccc);
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#ifdef HAVE_RANDOM
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::srandom(seed);
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#else
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srand(seed);
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#endif
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this->seeded_random = true;
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}
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#ifdef HAVE_RANDOM
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return ::random();
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#else
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return rand();
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#endif
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}
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RandomDataProvider*
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InsecureRandomDataProvider::getInstance()
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{
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static InsecureRandomDataProvider instance;
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return &instance;
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}
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