shred: use explicit_bzero

* NEWS: Document this.
* bootstrap.conf (gnulib_modules): Add explicit_bzero.
* gl/lib/randint.c (randint_free):
* gl/lib/randread.c (randread_free):
* src/blake2/blake2-impl.h (secure_zero_memory):
* src/shred.c (dopass, do_wipefd):
Prefer explicit_bzero to memset when erasing secrets.

2 files changed, 2 insertions, 2 deletions

diff --git a/gl/lib/randint.c b/gl/lib/randint.c
index 4561067e8..b15982f46 100644
--- a/gl/lib/randint.c
+++ b/gl/lib/randint.c
@@ -198,7 +198,7 @@ randint_genmax (struct randint_source *s, randint genmax)
 void
 randint_free (struct randint_source *s)
 {
-  memset (s, 0, sizeof *s);
+  explicit_bzero (s, sizeof *s);
   free (s);
 }
 
diff --git a/gl/lib/randread.c b/gl/lib/randread.c
index 9c70a1875..834f8446a 100644
--- a/gl/lib/randread.c
+++ b/gl/lib/randread.c
@@ -341,7 +341,7 @@ int
 randread_free (struct randread_source *s)
 {
   FILE *source = s->source;
-  memset (s, 0, sizeof *s);
+  explicit_bzero (s, sizeof *s);
   free (s);
   return (source ? fclose (source) : 0);
 }