1 files changed, 78 insertions, 0 deletions
diff --git a/lib/libc/gen/getentropy.c b/lib/libc/gen/getentropy.c
new file mode 100644
index 000000000000..6b8ad697b7e0
--- /dev/null
+++ b/lib/libc/gen/getentropy.c
@@ -0,0 +1,78 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org>
+ * 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 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 AUTHOR 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.
+ */
+
+#include <sys/param.h>
+#include <sys/random.h>
+
+#include <errno.h>
+#include <limits.h>
+#include <signal.h>
+#include <unistd.h>
+#include <ssp/ssp.h>
+
+#include "libc_private.h"
+
+static inline void
+_getentropy_fail(void)
+{
+	raise(SIGKILL);
+}
+
+int
+__ssp_real(getentropy)(void *buf, size_t buflen)
+{
+	ssize_t rd;
+
+	if (buflen > GETENTROPY_MAX) {
+		errno = EINVAL;
+		return (-1);
+	}
+
+	while (buflen > 0) {
+		rd = getrandom(buf, buflen, 0);
+		if (rd == -1) {
+			switch (errno) {
+			case EINTR:
+				continue;
+			case EFAULT:
+				return (-1);
+			default:
+				_getentropy_fail();
+			}
+		}
+
+		/* This cannot happen. */
+		if (rd == 0)
+			_getentropy_fail();
+
+		buf = (char *)buf + rd;
+		buflen -= rd;
+	}
+
+	return (0);
+}