core: New function gpgrt_wipememory.

* src/init.c (_gpgrt_wipememory): New.
* src/visibility.c (gpgrt_wipememory): New.
* src/visibility.h: Add it.
* src/gpg-error.def.in: Ditto.
* src/gpg-error.vers: Ditto.
--

GnuPG-bug-id: 6954

1 files changed, 19 insertions, 0 deletions

diff --git a/src/init.c b/src/init.c
index 493e3ba..c4b7e56 100644
--- a/src/init.c
+++ b/src/init.c
@@ -413,6 +413,25 @@ _gpgrt_free (void *a)
 
 
 void
+_gpgrt_wipememory (void *ptr, size_t len)
+{
+  if (ptr && len)
+    {
+#if defined(HAVE_W32_SYSTEM) && defined(SecureZeroMemory)
+      SecureZeroMemory (ptr, len);
+#elif defined(HAVE_EXPLICIT_BZERO)
+      explicit_bzero (ptr, len);
+#else
+      /* Prevent compiler from optimizing away the call to memset by
+       * accessing memset through volatile pointer. */
+      static void *(*volatile memset_ptr)(void *, int, size_t) = (void *)memset;
+      memset_ptr (ptr, 0, len);
+#endif
+    }
+}
+
+
+void
 _gpg_err_set_errno (int err)
 {
   errno = err;