Expose RDRAND RNG through FFI

6 files changed, 86 insertions, 46 deletions

diff --git a/src/lib/entropy/rdrand/rdrand.cpp b/src/lib/entropy/rdrand/rdrand.cpp
index 6a5b0f7c4..b8a74ce2f 100644
--- a/src/lib/entropy/rdrand/rdrand.cpp
+++ b/src/lib/entropy/rdrand/rdrand.cpp
@@ -8,12 +8,12 @@
 
 #include <botan/internal/rdrand.h>
 #include <botan/rdrand_rng.h>
-#include <botan/cpuid.h>
 
 namespace Botan {
 
-size_t Intel_Rdrand::poll(RandomNumberGenerator& rng) {
-   if(CPUID::has_rdrand() && BOTAN_ENTROPY_INTEL_RNG_POLLS > 0)
+size_t Intel_Rdrand::poll(RandomNumberGenerator& rng)
+   {
+   if(BOTAN_ENTROPY_INTEL_RNG_POLLS > 0 && RDRAND_RNG::available())
       {
       RDRAND_RNG rdrand_rng;
       secure_vector<uint8_t> buf(4 * BOTAN_ENTROPY_INTEL_RNG_POLLS);
diff --git a/src/lib/entropy/rdseed/rdseed.cpp b/src/lib/entropy/rdseed/rdseed.cpp
index fbb8f921e..fccc53f6a 100644
--- a/src/lib/entropy/rdseed/rdseed.cpp
+++ b/src/lib/entropy/rdseed/rdseed.cpp
@@ -15,7 +15,8 @@
 namespace Botan {
 
 BOTAN_FUNC_ISA("rdseed")
-size_t Intel_Rdseed::poll(RandomNumberGenerator& rng) {
+size_t Intel_Rdseed::poll(RandomNumberGenerator& rng)
+   {
    if(CPUID::has_rdseed())
       {
       for(size_t p = 0; p != BOTAN_ENTROPY_INTEL_RNG_POLLS; ++p)
diff --git a/src/lib/ffi/ffi_rng.cpp b/src/lib/ffi/ffi_rng.cpp
index 7e185f75d..e193d4123 100644
--- a/src/lib/ffi/ffi_rng.cpp
+++ b/src/lib/ffi/ffi_rng.cpp
@@ -10,6 +10,10 @@
 #include <botan/system_rng.h>
 #include <botan/auto_rng.h>
 
+#if defined(BOTAN_HAS_RDRAND_RNG)
+   #include <botan/rdrand_rng.h>
+#endif
+
 extern "C" {
 
 using namespace Botan_FFI;
@@ -36,15 +40,22 @@ int botan_rng_init(botan_rng_t* rng_out, const char* rng_type)
          {
          rng.reset(new Botan::Null_RNG);
          }
+#if defined(BOTAN_HAS_RDRAND_RNG)
+      else if(rng_type_s == "rdrand" && Botan::RDRAND_RNG::available())
+         {
+         rng.reset(new Botan::RDRAND_RNG);
+         }
+#endif
 #if defined(BOTAN_TARGET_OS_HAS_THREADS)
       else if(rng_type_s == "user-threadsafe")
          {
          rng.reset(new Botan::Serialized_RNG(new Botan::AutoSeeded_RNG));
          }
 #endif
-      else
+
+      if(!rng)
          {
-         return BOTAN_FFI_ERROR_BAD_PARAMETER;
+         return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
          }
 
       *rng_out = new botan_rng_struct(rng.release());
diff --git a/src/lib/rng/rdrand_rng/rdrand_rng.cpp b/src/lib/rng/rdrand_rng/rdrand_rng.cpp
index c365a5f76..a3ea25921 100644
--- a/src/lib/rng/rdrand_rng/rdrand_rng.cpp
+++ b/src/lib/rng/rdrand_rng/rdrand_rng.cpp
@@ -17,11 +17,17 @@ namespace Botan {
 
 RDRAND_RNG::RDRAND_RNG()
    {
-   if(!CPUID::has_rdrand())
+   if(!RDRAND_RNG::available())
       throw Exception("Current CPU does not support RDRAND instruction");
    }
 
 //static
+bool RDRAND_RNG::available()
+   {
+   return CPUID::has_rdrand();
+   }
+
+//static
 uint32_t RDRAND_RNG::rdrand()
    {
    for(;;)
diff --git a/src/lib/rng/rdrand_rng/rdrand_rng.h b/src/lib/rng/rdrand_rng/rdrand_rng.h
index 377de419f..3f6a33b64 100644
--- a/src/lib/rng/rdrand_rng/rdrand_rng.h
+++ b/src/lib/rng/rdrand_rng/rdrand_rng.h
@@ -30,6 +30,11 @@ class BOTAN_PUBLIC_API(2,0) RDRAND_RNG final : public Hardware_RNG
       static uint32_t rdrand();
 
       /**
+      * Return true if RDRAND is available on the current processor
+      */
+      static bool available();
+
+      /**
       * Constructor will throw if CPU does not have RDRAND bit set
       */
       RDRAND_RNG();
diff --git a/src/tests/test_ffi.cpp b/src/tests/test_ffi.cpp
index d6824afd1..ee16267a1 100644
--- a/src/tests/test_ffi.cpp
+++ b/src/tests/test_ffi.cpp
@@ -38,51 +38,14 @@ class FFI_Unit_Tests final : public Test
          {
          Test::Result result("FFI");
 
-         // RNG test and initialization
          botan_rng_t rng;
-
-         TEST_FFI_FAIL("invalid rng type", botan_rng_init, (&rng, "invalid_type"));
-
-         std::vector<uint8_t> outbuf(512);
-
-         if(TEST_FFI_OK(botan_rng_init, (&rng, "user-threadsafe")))
-            {
-            TEST_FFI_OK(botan_rng_get, (rng, outbuf.data(), outbuf.size()));
-            TEST_FFI_OK(botan_rng_reseed, (rng, 256));
-
-            botan_rng_t null_rng;
-            TEST_FFI_OK(botan_rng_init, (&null_rng, "null"));
-            TEST_FFI_RC(-20, botan_rng_reseed_from_rng, (rng, null_rng, 256));
-            TEST_FFI_RC(-20, botan_rng_get, (null_rng, outbuf.data(), outbuf.size()));
-            TEST_FFI_OK(botan_rng_destroy, (null_rng));
-
-            TEST_FFI_OK(botan_rng_destroy, (rng));
-            }
-
-         if(TEST_FFI_OK(botan_rng_init, (&rng, "user")))
+         if(!TEST_FFI_OK(botan_rng_init, (&rng, "user")))
             {
-            TEST_FFI_OK(botan_rng_get, (rng, outbuf.data(), outbuf.size()));
-            TEST_FFI_OK(botan_rng_reseed, (rng, 256));
-
-            botan_rng_t system_rng;
-            if(TEST_FFI_OK(botan_rng_init, (&system_rng, "system")))
-               {
-               TEST_FFI_OK(botan_rng_reseed_from_rng, (rng, system_rng, 256));
-               TEST_FFI_OK(botan_rng_destroy, (system_rng));
-               }
-
-            uint8_t not_really_entropy[32] = { 0 };
-            TEST_FFI_OK(botan_rng_add_entropy, (rng, not_really_entropy, 32));
-
-            // used for the rest of this function and destroyed at the end
-            }
-         else
-            {
-            result.test_note("Existing early due to missing FFI RNG");
             return {result};
             }
 
          std::vector<Test::Result> results;
+         results.push_back(ffi_test_rng());
          results.push_back(ffi_test_utils());
          results.push_back(ffi_test_errors());
          results.push_back(ffi_test_base64());
@@ -209,6 +172,60 @@ class FFI_Unit_Tests final : public Test
          return result;
          }
 
+      Test::Result ffi_test_rng()
+         {
+         Test::Result result("FFI RNG");
+
+         // RNG test and initialization
+         botan_rng_t rng;
+         botan_rng_t system_rng;
+         botan_rng_t rdrand_rng = nullptr;
+         botan_rng_t null_rng;
+
+         TEST_FFI_FAIL("invalid rng type", botan_rng_init, (&rng, "invalid_type"));
+
+         REQUIRE_FFI_OK(botan_rng_init, (&system_rng, "system"));
+         REQUIRE_FFI_OK(botan_rng_init, (&null_rng, "null"));
+
+         int rc = botan_rng_init(&rdrand_rng, "rdrand");
+         result.confirm("Either success or not implemented", rc == 0 || rc == BOTAN_FFI_ERROR_NOT_IMPLEMENTED);
+
+         std::vector<uint8_t> outbuf(512);
+
+         if(TEST_FFI_OK(botan_rng_init, (&rng, "user-threadsafe")))
+            {
+            TEST_FFI_OK(botan_rng_get, (rng, outbuf.data(), outbuf.size()));
+            TEST_FFI_OK(botan_rng_reseed, (rng, 256));
+
+            TEST_FFI_RC(-20, botan_rng_reseed_from_rng, (rng, null_rng, 256));
+            if(rdrand_rng)
+               {
+               TEST_FFI_OK(botan_rng_reseed_from_rng, (rng, rdrand_rng, 256));
+               }
+            TEST_FFI_RC(-20, botan_rng_get, (null_rng, outbuf.data(), outbuf.size()));
+
+            TEST_FFI_OK(botan_rng_destroy, (rng));
+            }
+
+         if(TEST_FFI_OK(botan_rng_init, (&rng, "user")))
+            {
+            TEST_FFI_OK(botan_rng_get, (rng, outbuf.data(), outbuf.size()));
+            TEST_FFI_OK(botan_rng_reseed, (rng, 256));
+
+            TEST_FFI_OK(botan_rng_reseed_from_rng, (rng, system_rng, 256));
+
+            uint8_t not_really_entropy[32] = { 0 };
+            TEST_FFI_OK(botan_rng_add_entropy, (rng, not_really_entropy, 32));
+            }
+
+         TEST_FFI_OK(botan_rng_destroy, (rng));
+         TEST_FFI_OK(botan_rng_destroy, (null_rng));
+         TEST_FFI_OK(botan_rng_destroy, (system_rng));
+         TEST_FFI_OK(botan_rng_destroy, (rdrand_rng));
+
+         return result;
+         }
+
       Test::Result ffi_test_rsa_cert()
          {
          Test::Result result("FFI RSA cert");