From a7afade1701a809f6a33b53525d59dd29b38d381 Mon Sep 17 00:00:00 2001
From: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Sun, 31 Jul 2016 13:43:00 +0200
Subject: clear passwords with explicit_bzero

Make sure to explicitly clear memory that is used for password input. memset
is often optimized out by the compiler.

Brought to attention by the OpenBSD community, see:
https://marc.info/?t=146989502600003&r=1&w=2
Thread subject: x11/slock: clear passwords with explicit_bzero

Changes:

- explicit_bzero.c import from libressl-portable.
- Makefile: add COMPATSRC for compatibility src.
- config.mk: add separate *BSD section in config.mk to simply uncomment it on
  these platforms.
---
 explicit_bzero.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 explicit_bzero.c

(limited to 'explicit_bzero.c')

diff --git a/explicit_bzero.c b/explicit_bzero.c
new file mode 100644
index 0000000..3e33ca8
--- /dev/null
+++ b/explicit_bzero.c
@@ -0,0 +1,19 @@
+/*	$OpenBSD: explicit_bzero.c,v 1.3 2014/06/21 02:34:26 matthew Exp $ */
+/*
+ * Public domain.
+ * Written by Matthew Dempsky.
+ */
+
+#include <string.h>
+
+__attribute__((weak)) void
+__explicit_bzero_hook(void *buf, size_t len)
+{
+}
+
+void
+explicit_bzero(void *buf, size_t len)
+{
+	memset(buf, 0, len);
+	__explicit_bzero_hook(buf, len);
+}
-- 
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