From 4e166987d7e7d37d1f5cc71c0eb7918dea4fe443 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <[email protected]>
Date: Thu, 4 May 2017 11:13:51 +0200
Subject: [PATCH libXdmcp 3/3] Add getentropy emulation through syscall

Signed-off-by: Benjamin Tissoires <[email protected]>
---
 Key.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git libXdmcp-1.1.3/Key.c libXdmcp-1.1.3/Key.c
index d61ad0e..4b0e9c0 100644
--- libXdmcp-1.1.3/Key.c
+++ libXdmcp-1.1.3/Key.c
@@ -76,6 +76,54 @@ insecure_getrandom_buf (unsigned char *auth, int len)
     getbits (highbits, auth + 4);
 }
 
+#ifndef HAVE_GETENTROPY
+#include <sys/syscall.h>
+#include <errno.h>
+
+/* code taken from libressl, license: */
+/*
+ * Copyright (c) 2014 Theo de Raadt <[email protected]>
+ * Copyright (c) 2014 Bob Beck <[email protected]>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Emulation of getentropy(2) as documented at:
+ * http://man.openbsd.org/getentropy.2
+ */
+#ifdef __NR_getrandom
+
+static int
+getentropy(void *buf, size_t len)
+{
+	int pre_errno = errno;
+	int ret;
+	if (len > 256)
+		return (-1);
+	do {
+		ret = syscall(__NR_getrandom, buf, len, 0);
+	} while (ret == -1 && errno == EINTR);
+
+	if (ret != len)
+		return (-1);
+	errno = pre_errno;
+
+	return (0);
+}
+#define HAVE_GETENTROPY 1
+#endif /* __NR_getrandom */
+
+#endif /* HAVE_GETENTROPY */
+
 static void
 arc4random_buf (void *auth, int len)
 {
-- 
2.9.3