From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:53357) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RQEqL-0005z4-1V for qemu-devel@nongnu.org; Tue, 15 Nov 2011 03:58:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RQEqJ-0003bg-K6 for qemu-devel@nongnu.org; Tue, 15 Nov 2011 03:58:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:4695) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RQEqJ-0003bY-7X for qemu-devel@nongnu.org; Tue, 15 Nov 2011 03:58:11 -0500 From: Avi Kivity Date: Tue, 15 Nov 2011 10:57:56 +0200 Message-Id: <1321347476-6546-1-git-send-email-avi@redhat.com> Subject: [Qemu-devel] [PATCH v6 1.0] configure: build position independent executables on x86 hosts List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori , qemu-devel@nongnu.org, Blue Swirl Cc: Paul Moore , Peter Maydell Change the default on x86 hosts to building PIE (position independent executables); instead of restricting the option to user-only targets, apply it to all targets. In addition, set the relocation sections to read-only (relro) when available; this reduces the attack surface by disallowing changes to relocation tables at runtime. While PIE reduces performance and relro increases load time, it greatly improves security, with the potential to reduce a code execution vulnerability to a self denial of service. Non-x86 are not changed, as they require TCG changes. Signed-off-by: Avi Kivity --- v6: fix subject line. sigh. v5: fix typos; only default enable for x86; mutually exclusive with -static v4: say it's v4 and for 1.0 v3: detect toolchain support for PIE at configure time v2: improve description to include relro configure | 55 +++++++++++++++++++++++++++++++++++++------------------ 1 files changed, 37 insertions(+), 18 deletions(-) diff --git a/configure b/configure index 6c77fbb..024e603 100755 --- a/configure +++ b/configure @@ -172,7 +172,7 @@ aix="no" blobs="yes" pkgversion="" check_utests="" -user_pie="no" +pie="" zero_malloc="" trace_backend="nop" trace_file="trace" @@ -701,9 +701,9 @@ for opt do ;; --disable-guest-base) guest_base="no" ;; - --enable-user-pie) user_pie="yes" + --enable-pie) pie="yes" ;; - --disable-user-pie) user_pie="no" + --disable-pie) pie="no" ;; --enable-uname-release=*) uname_release="$optarg" ;; @@ -1031,8 +1031,8 @@ echo " --disable-bsd-user disable all BSD usermode emulation targets" echo " --enable-guest-base enable GUEST_BASE support for usermode" echo " emulation targets" echo " --disable-guest-base disable GUEST_BASE support" -echo " --enable-user-pie build usermode emulation targets as PIE" -echo " --disable-user-pie do not build usermode emulation targets as PIE" +echo " --enable-pie build Position Independent Executables" +echo " --disable-pie do not build Position Independent Executables" echo " --fmod-lib path to FMOD library" echo " --fmod-inc path to FMOD includes" echo " --oss-lib path to OSS library" @@ -1099,6 +1099,37 @@ for flag in $gcc_flags; do fi done +if test "$pie" = "yes" -a "$static" = "yes" ; then + echo "static and pie are mutually incompatible" + exit 1 +fi + +if test "$pie" != "no" -a "$static" != "yes" ; then + case "$cpu" in + i386|x86_64) + pie="yes" + ;; + *) + ;; + esac +fi + +if test "$pie" = "yes" ; then + cat > $TMPC << EOF +int main(void) { return 0; } +EOF + if compile_prog "-fPIE -DPIE" "-Wl,-pie"; then + QEMU_CFLAGS="-fPIE -DPIE $QEMU_CFLAGS" + LDFLAGS="-Wl,-pie $LDFLAGS" + if compile_prog "-fPIE -DPIE" "-Wl,-pie -Wl,-z,relro -Wl,-z,now"; then + LDFLAGS="-Wl,-z,relro -Wl,-z,now $LDFLAGS" + fi + else + echo "Disabling PIE due to missing toolchain support" + pie="no" + fi +fi + # # Solaris specific configure tool chain decisions # @@ -2765,7 +2796,7 @@ echo "Documentation $docs" echo "uname -r $uname_release" echo "NPTL support $nptl" echo "GUEST_BASE $guest_base" -echo "PIE user targets $user_pie" +echo "PIE $pie" echo "vde support $vde" echo "Linux AIO support $linux_aio" echo "ATTR/XATTR support $attr" @@ -3225,9 +3256,6 @@ for d in libdis libdis-user; do symlink $source_path/Makefile.dis $d/Makefile echo > $d/config.mak done -if test "$static" = "no" -a "$user_pie" = "yes" ; then - echo "QEMU_CFLAGS+=-fpie" > libdis-user/config.mak -fi for target in $target_list; do target_dir="$target" @@ -3646,12 +3674,6 @@ if test "$target_softmmu" = "yes" ; then esac fi -if test "$target_user_only" = "yes" -a "$static" = "no" -a \ - "$user_pie" = "yes" ; then - cflags="-fpie $cflags" - ldflags="-pie $ldflags" -fi - if test "$target_softmmu" = "yes" -a \( \ "$TARGET_ARCH" = "microblaze" -o \ "$TARGET_ARCH" = "cris" \) ; then @@ -3775,9 +3797,6 @@ d=libuser mkdir -p $d mkdir -p $d/trace symlink $source_path/Makefile.user $d/Makefile -if test "$static" = "no" -a "$user_pie" = "yes" ; then - echo "QEMU_CFLAGS+=-fpie" > $d/config.mak -fi if test "$docs" = "yes" ; then mkdir -p QMP -- 1.7.7.1