2
1
mirror of https://github.com/qpdf/qpdf.git synced 2024-10-31 19:02:30 +00:00
qpdf/libqpdf/InsecureRandomDataProvider.cc
2022-04-16 11:39:14 -04:00

50 lines
1.1 KiB
C++

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