From patchwork Sat Feb 20 10:23:35 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nix X-Patchwork-Id: 10956 Received: (qmail 12314 invoked by alias); 20 Feb 2016 10:23:58 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 12155 invoked by uid 89); 20 Feb 2016 10:23:57 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.7 required=5.0 tests=AWL, BAYES_00, KAM_LAZY_DOMAIN_SECURITY, RP_MATCHES_RCVD autolearn=no version=3.3.2 spammy=differentiate, configureac, UD:ac, configure.ac X-HELO: mail.esperi.org.uk From: Nix To: libc-alpha@sourceware.org Cc: carlos@redhat.com Subject: [PATCH 01/12] Configury support for --enable-stack-protector. Date: Sat, 20 Feb 2016 10:23:35 +0000 Message-Id: <1455963826-21885-2-git-send-email-nix@esperi.org.uk> In-Reply-To: <1455963826-21885-1-git-send-email-nix@esperi.org.uk> References: <1455963826-21885-1-git-send-email-nix@esperi.org.uk> From: Nick Alcock This adds =all and =strong, with obvious semantics, and with a rather arbitrarily-chosen default off, which we might well want to change to something stronger once this patch has been tested by people other than me. We don't validate the value of the option yet: that's in a later patch. Nor do we use it for anything at this stage. We differentiate between 'the compiler understands -fstack-protector' and 'the user wanted -fstack-protector' so that we can pass -fno-stack-protector in appropriate places even if the user didn't want to turn on -fstack-protector for other parts. (This helps us overcome another existing limitation, that glibc doesn't work with GCC's hacked to pass in -fstack-protector by default.) We might want to add another configuration option to turn on -fstack-protector for nscd and other network-facing operations by default, but for now I've stuck with one option to control everything. --- configure.ac | 61 ++++++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 41 insertions(+), 20 deletions(-) diff --git a/configure.ac b/configure.ac index 3c766b7..804fac7 100644 --- a/configure.ac +++ b/configure.ac @@ -232,6 +232,18 @@ AC_ARG_ENABLE([bind-now], [bindnow=no]) AC_SUBST(bindnow) +dnl Build glibc with -fstack-protector, -fstack-protector-all, or +dnl -fstack-protector-strong. +AC_ARG_ENABLE([stack-protector], + AC_HELP_STRING([--enable-stack-protector=@<:@yes|no|all|strong@:>@], + [Detect stack overflows in glibc functions with large string buffers, or in all glibc functions]), + [enable_stack_protector=$enableval], + [enable_stack_protector=no]) +case x"$enable_stack_protector" in + xall|xyes|xno|xstrong) ;; + *) AC_MSG_ERROR([Not a valid argument for --enable-stack-protector]);; +esac + dnl On some platforms we cannot use dynamic loading. We must provide dnl static NSS modules. AC_ARG_ENABLE([static-nss], @@ -602,6 +614,35 @@ fi test -n "$base_machine" || base_machine=$machine AC_SUBST(base_machine) +AC_CACHE_CHECK(for -fstack-protector, libc_cv_ssp, [dnl +LIBC_TRY_CC_OPTION([$CFLAGS $CPPFLAGS -Werror -fstack-protector], + [libc_cv_ssp=yes], + [libc_cv_ssp=no]) +]) + +AC_CACHE_CHECK(for -fstack-protector-strong, libc_cv_ssp_strong, [dnl +LIBC_TRY_CC_OPTION([$CFLAGS $CPPFLAGS -Werror -fstack-protector-strong], + [libc_cv_ssp_strong=yes], + [libc_cv_ssp_strong=no]) +]) + +AC_CACHE_CHECK(for -fstack-protector-all, libc_cv_ssp_all, [dnl +LIBC_TRY_CC_OPTION([$CFLAGS $CPPFLAGS -Werror -fstack-protector-all], + [libc_cv_ssp_all=yes], + [libc_cv_ssp_all=no]) +]) + +stack_protector= +if test x$enable_stack_protector = xyes && test $libc_cv_ssp = yes; then + stack_protector=-fstack-protector +elif test x$enable_stack_protector = xall && test $libc_cv_ssp_all = yes; then + stack_protector=-fstack-protector-all +elif test x$enable_stack_protector = xstrong && test $libc_cv_ssp_strong = yes; then + stack_protector=-fstack-protector-strong +fi +AC_SUBST(libc_cv_ssp) +AC_SUBST(stack_protector) + # For the multi-arch option we need support in the assembler & linker. AC_CACHE_CHECK([for assembler and linker STT_GNU_IFUNC support], libc_cv_ld_gnu_indirect_function, [dnl @@ -1389,26 +1430,6 @@ else fi AC_SUBST(fno_unit_at_a_time) -AC_CACHE_CHECK(for -fstack-protector, libc_cv_ssp, [dnl -LIBC_TRY_CC_OPTION([$CFLAGS $CPPFLAGS -Werror -fstack-protector], - [libc_cv_ssp=yes], - [libc_cv_ssp=no]) -]) - -AC_CACHE_CHECK(for -fstack-protector-strong, libc_cv_ssp_strong, [dnl -LIBC_TRY_CC_OPTION([$CFLAGS $CPPFLAGS -Werror -fstack-protector-strong], - [libc_cv_ssp_strong=yes], - [libc_cv_ssp_strong=no]) -]) - -stack_protector= -if test "$libc_cv_ssp_strong" = "yes"; then - stack_protector="-fstack-protector-strong" -elif test "$libc_cv_ssp" = "yes"; then - stack_protector="-fstack-protector" -fi -AC_SUBST(stack_protector) - AC_CACHE_CHECK(whether cc puts quotes around section names, libc_cv_have_section_quotes, [cat > conftest.c <