1 files changed, 109 insertions, 0 deletions
diff --git a/entropy.c b/entropy.c
new file mode 100644
index 0000000..842c66f
--- /dev/null
+++ b/entropy.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2001 Damien Miller.  All rights reserved.
+ *
+ * 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 AUTHOR ``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 AUTHOR 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.
+ */
+
+#include "includes.h"
+
+#define RANDOM_SEED_SIZE 48
+
+#ifdef WITH_OPENSSL
+
+#include <sys/types.h>
+
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <openssl/rand.h>
+#include <openssl/crypto.h>
+#include <openssl/err.h>
+
+#include "openbsd-compat/openssl-compat.h"
+
+#include "ssh.h"
+#include "misc.h"
+#include "xmalloc.h"
+#include "atomicio.h"
+#include "pathnames.h"
+#include "log.h"
+#include "sshbuf.h"
+#include "ssherr.h"
+
+/*
+ * Portable OpenSSH PRNG seeding:
+ * If OpenSSL has not "internally seeded" itself (e.g. pulled data from
+ * /dev/random), then collect RANDOM_SEED_SIZE bytes of randomness from
+ * PRNGd.
+ */
+
+void
+seed_rng(void)
+{
+	unsigned char buf[RANDOM_SEED_SIZE];
+
+	/* Initialise libcrypto */
+	ssh_libcrypto_init();
+
+	if (!ssh_compatible_openssl(OPENSSL_VERSION_NUMBER,
+	    OpenSSL_version_num()))
+		fatal("OpenSSL version mismatch. Built against %lx, you "
+		    "have %lx", (u_long)OPENSSL_VERSION_NUMBER,
+		    OpenSSL_version_num());
+
+#ifndef OPENSSL_PRNG_ONLY
+	if (RAND_status() == 1)
+		debug3("RNG is ready, skipping seeding");
+	else {
+		if (seed_from_prngd(buf, sizeof(buf)) == -1)
+			fatal("Could not obtain seed from PRNGd");
+		RAND_add(buf, sizeof(buf), sizeof(buf));
+	}
+#endif /* OPENSSL_PRNG_ONLY */
+
+	if (RAND_status() != 1)
+		fatal("PRNG is not seeded");
+
+	/* Ensure arc4random() is primed */
+	arc4random_buf(buf, sizeof(buf));
+	explicit_bzero(buf, sizeof(buf));
+}
+
+#else /* WITH_OPENSSL */
+
+#include <stdlib.h>
+#include <string.h>
+
+/* Actual initialisation is handled in arc4random() */
+void
+seed_rng(void)
+{
+	unsigned char buf[RANDOM_SEED_SIZE];
+
+	/* Ensure arc4random() is primed */
+	arc4random_buf(buf, sizeof(buf));
+	explicit_bzero(buf, sizeof(buf));
+}
+
+#endif /* WITH_OPENSSL */