Add code to use Cryptech TRNG in place of Cryptlib's default entropy

sources.  This may need further attention, particularly once we start
working with buses other than the current I2C kludge.

1 files changed, 123 insertions, 0 deletions

diff --git a/src/cryptech_random.c b/src/cryptech_random.c
new file mode 100644
index 0000000..d8f711b
--- /dev/null
+++ b/src/cryptech_random.c
@@ -0,0 +1,123 @@
+/* 
+ * cryptech_random.c
+ * -----------------
+ *
+ * This is a shim to connect the Cryptech TRNG to Cryptlib's CSPRNG.
+ *
+ * Prototype HAL code for the Cryptech environment already provides
+ * the RNG code required by the HAL, but it doesn't look like Cryptlib
+ * itself ever calls that, it only seems to use the system device's
+ * random function.  So this shim just uses the code we already wrote
+ * to meet the HAL API requirement to feed Cryptlib's CSPRNG.
+ *
+ * Whether it makes sense to use what we hope is already a good TRNG
+ * just to provide entropy for a CSPRNG is a question for another day.
+ *
+ * Author: Rob Austein
+ * Copyright (c) 2014, SUNET
+ * 
+ * Redistribution and use in source and binary forms, with or 
+ * without modification, are permitted provided that the following 
+ * conditions are met: 
+ * 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in 
+ *    the documentation and/or other materials provided with the 
+ *    distribution. 
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#if defined( INC_ALL )
+  #include "crypt.h"
+  #include "context.h"
+  #include "hardware.h"
+  #include "random.h"
+#else
+  #include "crypt.h"
+  #include "context/context.h"
+  #include "device/hardware.h"
+  #include "random/random.h"
+#endif
+
+#define FAST_BUFSIZE    bitsToBytes(64)
+#define SLOW_BUFSIZE    (5 * FAST_BUFSIZE)
+
+void fastPoll(void)
+{
+  MESSAGE_DATA msgData;
+  unsigned char buffer[FAST_BUFSIZE];
+
+  if (hwGetRandom(buffer, sizeof(buffer)) == CRYPT_OK) {
+	setMessageData(&msgData, buffer, sizeof(buffer));
+    krnlSendMessage(SYSTEM_OBJECT_HANDLE, IMESSAGE_SETATTRIBUTE_S, &msgData, CRYPT_IATTRIBUTE_ENTROPY);
+    zeroise(buffer, sizeof(buffer));
+  }
+}
+
+void slowPoll(void)
+{
+  MESSAGE_DATA msgData;
+  unsigned char buffer[SLOW_BUFSIZE];
+  int quality = 100;
+
+  if (hwGetRandom(buffer, sizeof(buffer)) == CRYPT_OK) {
+	setMessageData(&msgData, buffer, sizeof(buffer));
+    krnlSendMessage(SYSTEM_OBJECT_HANDLE, IMESSAGE_SETATTRIBUTE_S, &msgData, CRYPT_IATTRIBUTE_ENTROPY);
+    zeroise(buffer, sizeof(buffer));
+    krnlSendMessage(SYSTEM_OBJECT_HANDLE, IMESSAGE_SETATTRIBUTE, &quality, CRYPT_IATTRIBUTE_ENTROPY_QUALITY);
+  }
+}
+
+/*
+ * Might patch these out in random/random.h eventually, but no-op
+ * stubs will do for testing.
+ */
+
+void initRandomPolling(void)
+{
+  return;
+}
+
+void endRandomPolling(void)
+{
+  return;
+}
+
+CHECK_RETVAL \
+int waitforRandomCompletion(const BOOLEAN force)
+{
+  return CRYPT_OK;
+}
+
+CHECK_RETVAL_BOOL \
+BOOLEAN checkForked(void)
+{
+  return FALSE;
+}
+
+/*
+ * "Any programmer who fails to comply with the standard naming, formatting,
+ *  or commenting conventions should be shot.  If it so happens that it is
+ *  inconvenient to shoot him, then he is to be politely requested to recode
+ *  his program in adherence to the above standard."
+ *                      -- Michael Spier, Digital Equipment Corporation
+ *
+ * Local variables:
+ * indent-tabs-mode: nil
+ * End:
+ */