Add a rdrand plugin stub detecting availability of RDRAND instructions

configure.in

@@ -112,6 +112,7 @@ ARG_DISBL_SET([sha1],           [disable SHA1 software implementation plugin.])
 ARG_DISBL_SET([sha2],           [disable SHA256/SHA384/SHA512 software implementation plugin.])
 ARG_DISBL_SET([fips-prf],       [disable FIPS PRF software implementation plugin.])
 ARG_DISBL_SET([gmp],            [disable GNU MP (libgmp) based crypto implementation plugin.])
+ARG_ENABL_SET([rdrand],         [enable Intel RDRAND random generator plugin.])
 ARG_DISBL_SET([random],         [disable RNG implementation on top of /dev/(u)random.])
 ARG_DISBL_SET([nonce],          [disable nonce generation plugin.])
 ARG_DISBL_SET([x509],           [disable X509 certificate implementation plugin.])
@@ -890,6 +891,7 @@ ADD_PLUGIN([sha1],                 [s charon openac scepclient pki scripts medsr
 ADD_PLUGIN([sha2],                 [s charon openac scepclient pki scripts medsrv attest nm])
 ADD_PLUGIN([md4],                  [s charon openac manager scepclient pki nm])
 ADD_PLUGIN([md5],                  [s charon openac scepclient pki scripts attest nm])
+ADD_PLUGIN([rdrand],               [s charon openac scepclient pki scripts medsrv attest nm])
 ADD_PLUGIN([random],               [s charon openac scepclient pki scripts medsrv attest nm])
 ADD_PLUGIN([nonce],                [s charon nm])
 ADD_PLUGIN([x509],                 [s charon openac scepclient pki scripts attest nm])
@@ -1015,6 +1017,7 @@ AM_CONDITIONAL(USE_SHA1, test x$sha1 = xtrue)
 AM_CONDITIONAL(USE_SHA2, test x$sha2 = xtrue)
 AM_CONDITIONAL(USE_FIPS_PRF, test x$fips_prf = xtrue)
 AM_CONDITIONAL(USE_GMP, test x$gmp = xtrue)
+AM_CONDITIONAL(USE_RDRAND, test x$rdrand = xtrue)
 AM_CONDITIONAL(USE_RANDOM, test x$random = xtrue)
 AM_CONDITIONAL(USE_NONCE, test x$nonce = xtrue)
 AM_CONDITIONAL(USE_X509, test x$x509 = xtrue)
@@ -1198,6 +1201,7 @@ AC_OUTPUT(
 	src/libstrongswan/plugins/sha2/Makefile
 	src/libstrongswan/plugins/fips_prf/Makefile
 	src/libstrongswan/plugins/gmp/Makefile
+	src/libstrongswan/plugins/rdrand/Makefile
 	src/libstrongswan/plugins/random/Makefile
 	src/libstrongswan/plugins/nonce/Makefile
 	src/libstrongswan/plugins/hmac/Makefile

src/libstrongswan/Makefile.am

@@ -204,6 +204,13 @@ if MONOLITHIC
 endif
 endif
 
+if USE_RDRAND
+  SUBDIRS += plugins/rdrand
+if MONOLITHIC
+  libstrongswan_la_LIBADD += plugins/rdrand/libstrongswan-rdrand.la
+endif
+endif
+
 if USE_RANDOM
   SUBDIRS += plugins/random
 if MONOLITHIC

src/libstrongswan/plugins/rdrand/Makefile.am

@@ -0,0 +1,15 @@
+
+INCLUDES = -I$(top_srcdir)/src/libstrongswan
+
+AM_CFLAGS = -rdynamic
+
+if MONOLITHIC
+noinst_LTLIBRARIES = libstrongswan-rdrand.la
+else
+plugin_LTLIBRARIES = libstrongswan-rdrand.la
+endif
+
+libstrongswan_rdrand_la_SOURCES = \
+	rdrand_plugin.h rdrand_plugin.c
+
+libstrongswan_rdrand_la_LDFLAGS = -module -avoid-version

src/libstrongswan/plugins/rdrand/rdrand_plugin.c

@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2012 Martin Willi
+ * Copyright (C) 2012 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "rdrand_plugin.h"
+
+#include <stdio.h>
+
+#include <library.h>
+#include <utils/debug.h>
+
+typedef struct private_rdrand_plugin_t private_rdrand_plugin_t;
+typedef enum cpuid_feature_t cpuid_feature_t;
+
+/**
+ * private data of rdrand_plugin
+ */
+struct private_rdrand_plugin_t {
+
+	/**
+	 * public functions
+	 */
+	rdrand_plugin_t public;
+};
+
+/**
+ * CPU feature flags, returned via cpuid(1)
+ */
+enum cpuid_feature_t {
+	CPUID_RDRAND =		(1<<30),
+};
+
+/**
+ * Get cpuid for info, return eax, ebx, ecx and edx.
+ * -fPIC requires to save ebx on IA-32.
+ */
+static void cpuid(u_int op, u_int *a, u_int *b, u_int *c, u_int *d)
+{
+#ifdef __x86_64__
+	asm("cpuid" : "=a" (*a), "=b" (*b), "=c" (*c), "=d" (*d) : "a" (op));
+#else /* __i386__ */
+	asm("pushl %%ebx;"
+		"cpuid;"
+		"movl %%ebx, %1;"
+		"popl %%ebx;"
+		: "=a" (*a), "=r" (*b), "=c" (*c), "=d" (*d) : "a" (op));
+#endif /* __x86_64__ / __i386__*/
+}
+
+/**
+ * Check if we have RDRAND instruction
+ */
+static bool have_rdrand()
+{
+	char vendor[3 * sizeof(u_int32_t) + 1];
+	u_int a, b, c, d;
+
+	cpuid(0, &a, &b, &c, &d);
+	/* VendorID string is in b-d-c (yes, in this order) */
+	snprintf(vendor, sizeof(vendor), "%.4s%.4s%.4s", &b, &d, &c);
+
+	/* check if we have an Intel CPU */
+	if (streq(vendor, "GenuineIntel"))
+	{
+		cpuid(1, &a, &b, &c, &d);
+		if (c & CPUID_RDRAND)
+		{
+			DBG1(DBG_LIB, "detected RDRAND support on %s CPU", vendor);
+			return TRUE;
+		}
+	}
+	DBG1(DBG_LIB, "no RDRAND support on %s CPU, disabled", vendor);
+	return FALSE;
+}
+
+METHOD(plugin_t, get_name, char*,
+	private_rdrand_plugin_t *this)
+{
+	return "rdrand";
+}
+
+METHOD(plugin_t, destroy, void,
+	private_rdrand_plugin_t *this)
+{
+	free(this);
+}
+
+/*
+ * see header file
+ */
+plugin_t *rdrand_plugin_create()
+{
+	private_rdrand_plugin_t *this;
+
+	INIT(this,
+		.public = {
+			.plugin = {
+				.get_name = _get_name,
+				.reload = (void*)return_false,
+				.destroy = _destroy,
+			},
+		},
+	);
+
+	have_rdrand();
+
+	return &this->public.plugin;
+}

src/libstrongswan/plugins/rdrand/rdrand_plugin.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2012 Martin Willi
+ * Copyright (C) 2012 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup rdrand_p rdrand
+ * @ingroup plugins
+ *
+ * @defgroup rdrand_plugin rdrand_plugin
+ * @{ @ingroup rdrand_p
+ */
+
+#ifndef RDRAND_PLUGIN_H_
+#define RDRAND_PLUGIN_H_
+
+#include <plugins/plugin.h>
+
+typedef struct rdrand_plugin_t rdrand_plugin_t;
+
+/**
+ * Plugin providing random generators based on Intels RDRAND instruction.
+ */
+struct rdrand_plugin_t {
+
+	/**
+	 * implements plugin interface
+	 */
+	plugin_t plugin;
+};
+
+#endif /** RDRAND_PLUGIN_H_ @}*/