* lib/explicit_bzero.c (explicit_bzero):
Simplify by just calling memset_explicit.
* m4/explicit_bzero.m4 (gl_PREREQ_EXPLICIT_BZERO):
Now a no-op.
* modules/explicit_bzero (Depends-on): Add memset_explicit.
(configure.ac): No need to worry about gl_PREREQ_EXPLICIT_BZERO.
---
ChangeLog | 8 +++++
lib/explicit_bzero.c | 69 +++++++-----------------------------------
m4/explicit_bzero.m4 | 7 ++---
modules/explicit_bzero | 4 +--
4 files changed, 22 insertions(+), 66 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index ea76fef399..26dfd4174c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
2022-11-27 Paul Eggert <egg...@cs.ucla.edu>
+ explicit_bzero: implement via memset_explicit
+ * lib/explicit_bzero.c (explicit_bzero):
+ Simplify by just calling memset_explicit.
+ * m4/explicit_bzero.m4 (gl_PREREQ_EXPLICIT_BZERO):
+ Now a no-op.
+ * modules/explicit_bzero (Depends-on): Add memset_explicit.
+ (configure.ac): No need to worry about gl_PREREQ_EXPLICIT_BZERO.
+
explicit_bzero: memset_explicit is standard
* doc/glibc-functions/explicit_bzero.texi:
Say that memset_explicit is preferred in new code.
diff --git a/lib/explicit_bzero.c b/lib/explicit_bzero.c
index 584f982924..fc309f81d6 100644
--- a/lib/explicit_bzero.c
+++ b/lib/explicit_bzero.c
@@ -1,74 +1,27 @@
/* Erasure of sensitive data, generic implementation.
Copyright (C) 2016-2022 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.
+ This file 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,
+ This file 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.
+ 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
- <https://www.gnu.org/licenses/>. */
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <https://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. */
-
-#if !_LIBC
-# include <config.h>
-#endif
-
-/* memset_s need this define */
-#if HAVE_MEMSET_S
-# define __STDC_WANT_LIB_EXT1__ 1
-#endif
+#include <config.h>
#include <string.h>
-#if defined _WIN32 && !defined __CYGWIN__
-# define WIN32_LEAN_AND_MEAN
-# include <windows.h>
-#endif
-
-#if _LIBC
-/* glibc-internal users use __explicit_bzero_chk, and explicit_bzero
- redirects to that. */
-# undef explicit_bzero
-#endif
-
/* 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)
{
-#if defined _WIN32 && !defined __CYGWIN__
- (void) SecureZeroMemory (s, len);
-#elif HAVE_EXPLICIT_MEMSET
- explicit_memset (s, '\0', len);
-#elif HAVE_MEMSET_S
- (void) memset_s (s, len, '\0', len);
-#elif defined __GNUC__ && !defined __clang__
- memset (s, '\0', len);
- /* Compiler barrier. */
- __asm__ volatile ("" ::: "memory");
-#elif defined __clang__
- memset (s, '\0', len);
- /* Compiler barrier. */
- /* With asm ("" ::: "memory") LLVM analyzes uses of 's' and finds that the
- whole thing is dead and eliminates it. Use 'g' to work around this
- problem. See <https://bugs.llvm.org/show_bug.cgi?id=15495#c11>. */
- __asm__ volatile ("" : : "g"(s) : "memory");
-#else
- /* Invoke memset through a volatile function pointer. This defeats compiler
- optimizations. */
- void * (* const volatile volatile_memset) (void *, int, size_t) = memset;
- (void) volatile_memset (s, '\0', len);
-#endif
+ memset_explicit (s, 0, len);
}
diff --git a/m4/explicit_bzero.m4 b/m4/explicit_bzero.m4
index 3b4ef8c3cc..6e6f2b4037 100644
--- a/m4/explicit_bzero.m4
+++ b/m4/explicit_bzero.m4
@@ -16,8 +16,5 @@ AC_DEFUN([gl_FUNC_EXPLICIT_BZERO],
fi
])
-AC_DEFUN([gl_PREREQ_EXPLICIT_BZERO],
-[
- AC_CHECK_FUNCS([explicit_memset])
- AC_CHECK_FUNCS_ONCE([memset_s])
-])
+dnl Defined for backward compatibility.
+AC_DEFUN([gl_PREREQ_EXPLICIT_BZERO], [:])
diff --git a/modules/explicit_bzero b/modules/explicit_bzero
index bb5f8a5310..8ba9a06ada 100644
--- a/modules/explicit_bzero
+++ b/modules/explicit_bzero
@@ -7,14 +7,12 @@ m4/explicit_bzero.m4
Depends-on:
extensions
+memset_explicit
string
configure.ac:
gl_FUNC_EXPLICIT_BZERO
gl_CONDITIONAL([GL_COND_OBJ_EXPLICIT_BZERO], [test $HAVE_EXPLICIT_BZERO = 0])
-AM_COND_IF([GL_COND_OBJ_EXPLICIT_BZERO], [
- gl_PREREQ_EXPLICIT_BZERO
-])
gl_STRING_MODULE_INDICATOR([explicit_bzero])
Makefile.am:
--
2.37.2
