add freezero(3) replacement

ok dtucker@

configure.ac

@@ -1696,6 +1696,7 @@ AC_CHECK_FUNCS([ \
 	fchmod \
 	fchown \
 	freeaddrinfo \
+	freezero \
 	fstatfs \
 	fstatvfs \
 	futimes \

openbsd-compat/Makefile.in

@@ -16,7 +16,7 @@ RANLIB=@RANLIB@
 INSTALL=@INSTALL@
 LDFLAGS=-L. @LDFLAGS@
 
-OPENBSD=base64.o basename.o bcrypt_pbkdf.o bindresvport.o blowfish.o daemon.o dirname.o fmt_scaled.o getcwd.o getgrouplist.o getopt_long.o getrrsetbyname.o glob.o inet_aton.o inet_ntoa.o inet_ntop.o mktemp.o pwcache.o readpassphrase.o reallocarray.o realpath.o recallocarray.o rresvport.o setenv.o setproctitle.o sha1.o sha2.o rmd160.o md5.o sigact.o strcasestr.o strlcat.o strlcpy.o strmode.o strnlen.o strptime.o strsep.o strtonum.o strtoll.o strtoul.o strtoull.o timingsafe_bcmp.o vis.o blowfish.o bcrypt_pbkdf.o explicit_bzero.o
+OPENBSD=base64.o basename.o bcrypt_pbkdf.o bindresvport.o blowfish.o daemon.o dirname.o fmt_scaled.o getcwd.o getgrouplist.o getopt_long.o getrrsetbyname.o glob.o inet_aton.o inet_ntoa.o inet_ntop.o mktemp.o pwcache.o readpassphrase.o reallocarray.o realpath.o recallocarray.o rresvport.o setenv.o setproctitle.o sha1.o sha2.o rmd160.o md5.o sigact.o strcasestr.o strlcat.o strlcpy.o strmode.o strnlen.o strptime.o strsep.o strtonum.o strtoll.o strtoul.o strtoull.o timingsafe_bcmp.o vis.o blowfish.o bcrypt_pbkdf.o explicit_bzero.o freezero.o
 
 COMPAT=arc4random.o bsd-asprintf.o bsd-closefrom.o bsd-cray.o bsd-cygwin_util.o bsd-getpeereid.o getrrsetbyname-ldns.o bsd-err.o bsd-getpagesize.o bsd-misc.o bsd-nextstep.o bsd-openpty.o bsd-poll.o bsd-setres_id.o bsd-snprintf.o bsd-statvfs.o bsd-waitpid.o fake-rfc2553.o openssl-compat.o xcrypt.o kludge-fd_set.o
 

openbsd-compat/freezero.c

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net>
+ *
+ * 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.
+ */
+
+#include "includes.h"
+
+#ifndef HAVE_FREEZERO
+
+void
+freezero(void *ptr, size_t sz)
+{
+	explicit_bzero(ptr, sz);
+	free(ptr);
+}
+
+#endif /* HAVE_FREEZERO */
+

openbsd-compat/openbsd-compat.h

@@ -304,6 +304,10 @@ int	bcrypt_pbkdf(const char *, size_t, const u_int8_t *, size_t,
 void explicit_bzero(void *p, size_t n);
 #endif
 
+#ifndef HAVE_FREEZERO
+void freezero(void *, size_t);
+#endif
+
 char *xcrypt(const char *password, const char *salt);
 char *shadow_pw(struct passwd *pw);