1 files changed, 38 insertions, 0 deletions
diff --git a/string/explicit_bzero.c b/string/explicit_bzero.c
new file mode 100644
index 0000000000..6712cad5a6
--- /dev/null
+++ b/string/explicit_bzero.c
@@ -0,0 +1,38 @@
+/* Erasure of sensitive data, generic implementation.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* An assembler implementation of explicit_bzero can be created as an
+   assembler alias of an optimized bzero implementation.
+   Architecture-specific implementations also need to define
+   __explicit_bzero_chk.  */
+
+#include <string.h>
+
+/* glibc-internal users use __explicit_bzero_chk, and explicit_bzero
+   redirects to that.  */
+#undef explicit_bzero
+
+/* Set LEN bytes of S to 0.  The compiler will not delete a call to
+   this function, even if S is dead after the call.  */
+void
+explicit_bzero (void *s, size_t len)
+{
+  memset (s, '\0', len);
+  /* Compiler barrier.  */
+  asm volatile ("" ::: "memory");
+}