From 1251607b046a2900bb6c1857d7d690f44b96926a Mon Sep 17 00:00:00 2001
From: David Garske <david@wolfssl.com>
Date: Fri, 17 Mar 2017 13:44:53 -0700
Subject: [PATCH] Retain existing HAVE_HASHDRBG functionality and only disable
 if ./configure --disable-hashdrbg or WC_NO_HASHDRBG defined. Fix use of
 warning with VS. Fix to only use rng seed as source if no DRBG.

---
 configure.ac               |  4 +++-
 wolfcrypt/src/random.c     | 10 +++++-----
 wolfssl/wolfcrypt/random.h | 13 +++++++++++--
 3 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/configure.ac b/configure.ac
index 77bf2fbe5..93c766194 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1690,11 +1690,13 @@ if test "x$ENABLED_HASHDRBG" = "xyes"
 then
     AM_CFLAGS="$AM_CFLAGS -DHAVE_HASHDRBG"
 else
-    # turn on Hash DRBG if FIPS is on or ARC4 is off
+    # turn on Hash DRBG if FIPS is on
     if test "x$ENABLED_FIPS" = "xyes"
     then
         AM_CFLAGS="$AM_CFLAGS -DHAVE_HASHDRBG"
         ENABLED_HASHDRBG=yes
+    else
+        AM_CFLAGS="$AM_CFLAGS -DWC_NO_HASHDRBG"
     fi
 fi
 
diff --git a/wolfcrypt/src/random.c b/wolfcrypt/src/random.c
index a783141e8..1c45f0872 100644
--- a/wolfcrypt/src/random.c
+++ b/wolfcrypt/src/random.c
@@ -634,8 +634,7 @@ int wc_RNG_GenerateBlock(WC_RNG* rng, byte* output, word32 sz)
         ret = RNG_FAILURE_E;
         rng->status = DRBG_FAILED;
     }
-    return ret;
-#endif /* HAVE_HASHDRBG */
+#else
 
     /* try using the generate seed direectly */
     ret = wc_GenerateSeed(&rng->seed, output, sz);
@@ -643,9 +642,10 @@ int wc_RNG_GenerateBlock(WC_RNG* rng, byte* output, word32 sz)
         return 0;
 
     /* if we get here then there is an RNG configuration error */
-    (void)ret;
-    (void)sz;
-    return RNG_FAILURE_E;
+    ret = RNG_FAILURE_E;
+#endif /* HAVE_HASHDRBG */
+
+    return ret;
 }
 
 
diff --git a/wolfssl/wolfcrypt/random.h b/wolfssl/wolfcrypt/random.h
index a44ff8103..7ab7c7d06 100644
--- a/wolfssl/wolfcrypt/random.h
+++ b/wolfssl/wolfcrypt/random.h
@@ -45,10 +45,15 @@
     #define CUSTOM_RAND_TYPE    byte
 #endif
 
+/* make sure Hash DRBG is enabled, unless WC_NO_HASHDRBG is defined */
+#ifndef WC_NO_HASHDRBG
+    #undef  HAVE_HASHDRBG
+    #define HAVE_HASHDRBG
+#endif
+
 
 #ifndef HAVE_FIPS /* avoid redefining structs and macros */
 
-
 /* RNG supports the following sources (in order):
  * 1. CUSTOM_RAND_GENERATE_BLOCK: Defines name of function as RNG source and
  *     bypasses the options below.
@@ -77,7 +82,11 @@
 #elif defined(HAVE_INTEL_RDRAND)
 #elif defined(HAVE_WNR)
 #else
-     #warning No RNG source defined. Using wc_GenerateSeed directly
+    #ifndef _MSC_VER
+        #warning "No RNG source defined. Using wc_GenerateSeed directly"
+    #else
+        #pragma message("Warning: No RNG source defined. Using wc_GenerateSeed directly")
+    #endif
 #endif
 
 #ifdef HAVE_WNR