1 files changed, 83 insertions, 0 deletions
diff --git a/src/random.c b/src/random.c
new file mode 100644
index 0000000..9688d35
--- /dev/null
+++ b/src/random.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2018 Yubico AB. All rights reserved.
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file.
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#ifdef HAVE_SYS_RANDOM_H
+#include <sys/random.h>
+#endif
+
+#include <fcntl.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include "fido.h"
+
+#if defined(_WIN32)
+#include <windows.h>
+
+#include <winternl.h>
+#include <winerror.h>
+#include <stdio.h>
+#include <bcrypt.h>
+#include <sal.h>
+
+int
+fido_get_random(void *buf, size_t len)
+{
+	NTSTATUS status;
+
+	status = BCryptGenRandom(NULL, buf, (ULONG)len,
+	    BCRYPT_USE_SYSTEM_PREFERRED_RNG);
+
+	if (!NT_SUCCESS(status))
+		return (-1);
+
+	return (0);
+}
+#elif defined(HAVE_ARC4RANDOM_BUF)
+int
+fido_get_random(void *buf, size_t len)
+{
+	arc4random_buf(buf, len);
+	return (0);
+}
+#elif defined(HAVE_GETRANDOM)
+int
+fido_get_random(void *buf, size_t len)
+{
+	ssize_t	r;
+
+	if ((r = getrandom(buf, len, 0)) < 0 || (size_t)r != len)
+		return (-1);
+
+	return (0);
+}
+#elif defined(HAVE_DEV_URANDOM)
+int
+fido_get_random(void *buf, size_t len)
+{
+	int	fd = -1;
+	int	ok = -1;
+	ssize_t	r;
+
+	if ((fd = open(FIDO_RANDOM_DEV, O_RDONLY)) < 0)
+		goto fail;
+	if ((r = read(fd, buf, len)) < 0 || (size_t)r != len)
+		goto fail;
+
+	ok = 0;
+fail:
+	if (fd != -1)
+		close(fd);
+
+	return (ok);
+}
+#else
+#error "please provide an implementation of fido_get_random() for your platform"
+#endif /* _WIN32 */