mirror of https://github.com/qpdf/qpdf.git
134 lines
3.4 KiB
C++
134 lines
3.4 KiB
C++
#include <qpdf/SecureRandomDataProvider.hh>
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#include <qpdf/qpdf-config.h>
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#include <qpdf/QUtil.hh>
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#ifdef _WIN32
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# include <windows.h>
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# include <direct.h>
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# include <io.h>
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# ifndef SKIP_OS_SECURE_RANDOM
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# include <wincrypt.h>
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# endif
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#endif
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SecureRandomDataProvider::SecureRandomDataProvider()
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{
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}
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SecureRandomDataProvider::~SecureRandomDataProvider()
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{
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}
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#ifdef SKIP_OS_SECURE_RANDOM
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void
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SecureRandomDataProvider::provideRandomData(unsigned char* data, size_t len)
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{
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throw std::logic_error("SecureRandomDataProvider::provideRandomData called when support was not compiled in");
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}
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RandomDataProvider*
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SecureRandomDataProvider::getInstance()
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{
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return 0;
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}
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#else
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#ifdef _WIN32
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class WindowsCryptProvider
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{
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public:
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WindowsCryptProvider()
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{
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if (!CryptAcquireContext(&crypt_prov,
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"Container",
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NULL,
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PROV_RSA_FULL,
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0))
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{
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#if ((defined(__GNUC__) && ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406) || \
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defined(__clang__))
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# pragma GCC diagnostic push
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# pragma GCC diagnostic ignored "-Wold-style-cast"
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# pragma GCC diagnostic ignored "-Wsign-compare"
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#endif
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if (GetLastError() == NTE_BAD_KEYSET)
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#if ((defined(__GNUC__) && ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406) || \
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defined(__clang__))
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# pragma GCC diagnostic pop
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#endif
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{
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if (! CryptAcquireContext(&crypt_prov,
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"Container",
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NULL,
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PROV_RSA_FULL,
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CRYPT_NEWKEYSET))
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{
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throw std::runtime_error(
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"unable to acquire crypt context with new keyset");
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}
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}
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else
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{
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throw std::runtime_error("unable to acquire crypt context");
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}
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}
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}
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~WindowsCryptProvider()
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{
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// Ignore error
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CryptReleaseContext(crypt_prov, 0);
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}
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HCRYPTPROV crypt_prov;
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};
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#endif
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void
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SecureRandomDataProvider::provideRandomData(unsigned char* data, size_t len)
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{
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#if defined(_WIN32)
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// Optimization: make the WindowsCryptProvider static as long as
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// it can be done in a thread-safe fashion.
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WindowsCryptProvider c;
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if (! CryptGenRandom(c.crypt_prov, len, reinterpret_cast<BYTE*>(data)))
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{
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throw std::runtime_error("unable to generate secure random data");
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}
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#elif defined(RANDOM_DEVICE)
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// Optimization: wrap the file open and close in a class so that
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// the file is closed in a destructor, then make this static to
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// keep the file handle open. Only do this if it can be done in a
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// thread-safe fashion.
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FILE* f = QUtil::safe_fopen(RANDOM_DEVICE, "rb");
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size_t fr = fread(data, 1, len, f);
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fclose(f);
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if (fr != len)
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{
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throw std::runtime_error(
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"unable to read " +
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QUtil::int_to_string(len) +
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" bytes from " + std::string(RANDOM_DEVICE));
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}
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#else
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# error "Don't know how to generate secure random numbers on this platform. See random number generation in the top-level README.md"
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#endif
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}
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RandomDataProvider*
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SecureRandomDataProvider::getInstance()
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{
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static SecureRandomDataProvider instance;
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return &instance;
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}
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#endif
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