diff options
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | lib/explicit_bzero.c | 69 | ||||
| -rw-r--r-- | m4/explicit_bzero.m4 | 6 | ||||
| -rw-r--r-- | modules/explicit_bzero | 4 |
4 files changed, 19 insertions, 67 deletions
@@ -1,5 +1,12 @@ 2022-11-27 Paul Eggert <eggert@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): Remove. + All uses removed. + * modules/explicit_bzero (Depends-on): Add memset_explicit. + 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..6c0d4c2336 100644 --- a/m4/explicit_bzero.m4 +++ b/m4/explicit_bzero.m4 @@ -15,9 +15,3 @@ AC_DEFUN([gl_FUNC_EXPLICIT_BZERO], HAVE_EXPLICIT_BZERO=0 fi ]) - -AC_DEFUN([gl_PREREQ_EXPLICIT_BZERO], -[ - AC_CHECK_FUNCS([explicit_memset]) - AC_CHECK_FUNCS_ONCE([memset_s]) -]) 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: |