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explicit_bzero(s, n) is the same as memset(s, 0, n), except that the compiler is not allowed to delete a call to explicit_bzero even if the memory pointed to by 's' is dead after the call. Right now, this effect is achieved externally by having explicit_bzero be a function whose semantics are unknown to the compiler, and internally, with a no-op asm statement that clobbers memory. This does mean that small explicit_bzero operations cannot be expanded inline as small memset operations can, but on the other hand, small memset operations do get deleted by the compiler. Hopefully full compiler support for explicit_bzero will happen relatively soon. There are two new tests: test-explicit_bzero.c verifies the visible semantics in the same way as the existing test-bzero.c, and tst-xbzero-opt.c verifies the not-being-optimized-out property. The latter is conceptually based on a test written by Matthew Dempsky for the OpenBSD regression suite. The crypt() implementation has an immediate use for this new feature. We avoid having to add a GLIBC_PRIVATE alias for explicit_bzero by running all of libcrypt's calls through the fortified variant, __explicit_bzero_chk, which is in the impl namespace anyway. Currently I'm not aware of anything in libc proper that needs this, but the glue is all in place if it does become necessary. The legacy DES implementation wasn't bothering to clear its buffers, so I added that, mostly for consistency's sake. * string/explicit_bzero.c: New routine. * string/test-explicit_bzero.c, string/tst-xbzero-opt.c: New tests. * string/Makefile (routines, strop-tests, tests): Add them. * string/test-memset.c: Add ifdeffage for testing explicit_bzero. * string/string.h [__USE_MISC]: Declare explicit_bzero. * debug/explicit_bzero_chk.c: New routine. * debug/Makefile (routines): Add it. * debug/tst-chk1.c: Test fortification of explicit_bzero. * string/bits/string3.h: Fortify explicit_bzero. * manual/string.texi: Document explicit_bzero. * NEWS: Mention addition of explicit_bzero. * crypt/crypt-entry.c (__crypt_r): Clear key-dependent intermediate data before returning, using explicit_bzero. * crypt/md5-crypt.c (__md5_crypt_r): Likewise. * crypt/sha256-crypt.c (__sha256_crypt_r): Likewise. * crypt/sha512-crypt.c (__sha512_crypt_r): Likewise. * include/string.h: Redirect internal uses of explicit_bzero to __explicit_bzero_chk[_internal]. * string/Versions [GLIBC_2.25]: Add explicit_bzero. * debug/Versions [GLIBC_2.25]: Add __explicit_bzero_chk. * sysdeps/arm/nacl/libc.abilist * sysdeps/unix/sysv/linux/aarch64/libc.abilist * sysdeps/unix/sysv/linux/alpha/libc.abilist * sysdeps/unix/sysv/linux/arm/libc.abilist * sysdeps/unix/sysv/linux/hppa/libc.abilist * sysdeps/unix/sysv/linux/i386/libc.abilist * sysdeps/unix/sysv/linux/ia64/libc.abilist * sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist * sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist * sysdeps/unix/sysv/linux/microblaze/libc.abilist * sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist * sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist * sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist * sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist * sysdeps/unix/sysv/linux/nios2/libc.abilist * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist * sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist * sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist * sysdeps/unix/sysv/linux/sh/libc.abilist * sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist * sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist * sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist * sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist * sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist * sysdeps/unix/sysv/linux/x86_64/64/libc.abilist * sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Add entries for explicit_bzero and __explicit_bzero_chk.
93 lines
3.3 KiB
Makefile
93 lines
3.3 KiB
Makefile
# Copyright (C) 1991-2016 Free Software Foundation, Inc.
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# This file is part of the GNU C Library.
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# The GNU C Library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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# The GNU C Library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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# You should have received a copy of the GNU Lesser General Public
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# License along with the GNU C Library; if not, see
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# <http://www.gnu.org/licenses/>.
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#
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# Sub-makefile for string portion of library.
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#
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subdir := string
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include ../Makeconfig
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headers := string.h strings.h memory.h endian.h bits/endian.h \
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argz.h envz.h byteswap.h bits/byteswap.h bits/byteswap-16.h \
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bits/string.h bits/string2.h bits/string3.h
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routines := strcat strchr strcmp strcoll strcpy strcspn \
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strverscmp strdup strndup \
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strerror _strerror strlen strnlen \
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strncat strncmp strncpy \
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strrchr strpbrk strsignal strspn strstr strtok \
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strtok_r strxfrm memchr memcmp memmove memset \
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mempcpy bcopy bzero ffs ffsll stpcpy stpncpy \
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strcasecmp strncase strcasecmp_l strncase_l \
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memccpy memcpy wordcopy strsep strcasestr \
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swab strfry memfrob memmem rawmemchr strchrnul \
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$(addprefix argz-,append count create ctsep next \
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delete extract insert stringify \
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addsep replace) \
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envz basename \
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strcoll_l strxfrm_l string-inlines memrchr \
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xpg-strerror strerror_l explicit_bzero
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strop-tests := memchr memcmp memcpy memmove mempcpy memset memccpy \
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stpcpy stpncpy strcat strchr strcmp strcpy strcspn \
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strlen strncmp strncpy strpbrk strrchr strspn memmem \
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strstr strcasestr strnlen strcasecmp strncasecmp \
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strncat rawmemchr strchrnul bcopy bzero memrchr \
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explicit_bzero
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tests := tester inl-tester noinl-tester testcopy test-ffs \
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tst-strlen stratcliff tst-svc tst-inlcall \
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bug-strncat1 bug-strspn1 bug-strpbrk1 tst-bswap \
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tst-strtok tst-strxfrm bug-strcoll1 tst-strfry \
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bug-strtok1 $(addprefix test-,$(strop-tests)) \
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bug-envz1 tst-strxfrm2 tst-endian tst-svc2 \
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tst-strtok_r bug-strcoll2 tst-cmp tst-xbzero-opt
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xtests = tst-strcoll-overflow
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ifeq ($(run-built-tests),yes)
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tests-special += $(objpfx)tst-svc-cmp.out
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endif
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include ../Rules
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CFLAGS-inl-tester.c = -fno-builtin
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CFLAGS-noinl-tester.c = -fno-builtin
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CFLAGS-tst-strlen.c = -fno-builtin
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CFLAGS-stratcliff.c = -fno-builtin
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CFLAGS-test-ffs.c = -fno-builtin
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CFLAGS-tst-inlcall.c = -fno-builtin
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ifeq ($(run-built-tests),yes)
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$(objpfx)tst-svc-cmp.out: tst-svc.expect $(objpfx)tst-svc.out
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cmp $^ > $@; \
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$(evaluate-test)
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LOCALES := de_DE.UTF-8 en_US.ISO-8859-1 en_US.UTF-8 \
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tr_TR.ISO-8859-9 tr_TR.UTF-8 cs_CZ.UTF-8 \
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da_DK.ISO-8859-1
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include ../gen-locales.mk
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$(objpfx)test-strcasecmp.out: $(gen-locales)
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$(objpfx)test-strncasecmp.out: $(gen-locales)
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$(objpfx)tst-strxfrm.out: $(gen-locales)
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$(objpfx)tst-strxfrm2.out: $(gen-locales)
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# bug-strcoll2 needs cs_CZ.UTF-8 and da_DK.ISO-8859-1.
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$(objpfx)bug-strcoll2.out: $(gen-locales)
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endif
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