Untested support for using CryptGenRandom in System_RNG

1 files changed, 32 insertions, 0 deletions

diff --git a/src/lib/rng/system_rng/system_rng.cpp b/src/lib/rng/system_rng/system_rng.cpp
index afffb69cc..cdf85ef29 100644
--- a/src/lib/rng/system_rng/system_rng.cpp
+++ b/src/lib/rng/system_rng/system_rng.cpp
@@ -7,6 +7,15 @@
 
 #include <botan/system_rng.h>
 
+#if defined(BOTAN_TARGET_OS_IS_WINDOWS)
+
+#include <windows.h>
+#include <wincrypt.h>
+#undef min
+#undef max
+
+#else
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -14,6 +23,8 @@
 #include <string.h>
 #include <errno.h>
 
+#endif
+
 namespace Botan {
 
 namespace {
@@ -33,23 +44,43 @@ class System_RNG : public RandomNumberGenerator
       void reseed(size_t) {}
       void add_entropy(const byte[], size_t) {}
    private:
+
+#if defined(BOTAN_TARGET_OS_IS_WINDOWS)
+      HCRYPTPROV m_prov;
+#else
       int m_fd;
+#endif
    };
 
 System_RNG::System_RNG()
    {
+#if defined(BOTAN_TARGET_OS_IS_WINDOWS)
+
+   if(!CryptAcquireContext(&m_prov, 0, 0, RSA_FULL, CRYPT_VERIFYCONTEXT))
+      throw std::runtime_error("System_RNG failed to acquire crypto provider");
+
+#else
+
    m_fd = ::open("/dev/urandom", O_RDONLY);
    if(m_fd < 0)
       throw std::runtime_error("System_RNG failed to open /dev/urandom");
+#endif
    }
 
 System_RNG::~System_RNG()
    {
+#if defined(BOTAN_TARGET_OS_IS_WINDOWS)
+   ::CryptReleaseContext(m_prov, 0);
+#else
    ::close(m_fd);
+#endif
    }
 
 void System_RNG::randomize(byte buf[], size_t len)
    {
+#if defined(BOTAN_TARGET_OS_IS_WINDOWS)
+   ::CryptGenRandom(m_prov, static_cast<DWORD>(len), buf))
+#else
    while(len)
       {
       ssize_t got = ::read(m_fd, buf, len);
@@ -66,6 +97,7 @@ void System_RNG::randomize(byte buf[], size_t len)
       buf += got;
       len -= got;
       }
+#endif
    }
 
 }