From 66a704c43cfec810fea67a6959f2d1c94f4d594f Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Mon, 26 Dec 2016 10:08:54 +0100 Subject: Work even with compilers which enable -fstack-protector by default [BZ #7065] With all the machinery we just added, we can easily arrange to work even when the compiler passes in -fstack-protector automatically: all the necessary bits of glibc are always compiled with -fno-stack-protector now. So tear out the check in configure, and add appropriate calls to -fno-stack-protector in tests that need them (largely those that use -nostdlib), since we don't yet have a __stack_chk_fail that those tests can rely upon. (GCC often provides one, but we cannot rely on this, especially not when bootstrapping.) When stack protection is disabled, explicitly pass -fno-stack-protector to everything, to stop a compiler hacked to enable it from inserting calls to __stack_chk_fail via the PLT in every object file. --- configure | 90 ++++++++++++++++++--------------------------------------------- 1 file changed, 25 insertions(+), 65 deletions(-) (limited to 'configure') diff --git a/configure b/configure index b300795..c88f6fe 100755 --- a/configure +++ b/configure @@ -4010,11 +4010,25 @@ elif test "$enable_stack_protector" = strong && test "$libc_cv_ssp_strong" = yes stack_protector="-fstack-protector-strong" $as_echo "#define STACK_PROTECTOR_LEVEL 3" >>confdefs.h +else + stack_protector="-fno-stack-protector" + $as_echo "#define STACK_PROTECTOR_LEVEL 0" >>confdefs.h + fi +if test -n "$stack_protector"; then + no_ssp=-fno-stack-protector +else + no_ssp= + + if test "$enable_stack_protector" != no; then + as_fn_error $? "--enable-stack-protector=$enable_stack_protector specified, but specified level of stack protection is not supported by the compiler." "$LINENO" 5 + fi +fi + # For the multi-arch option we need support in the assembler & linker. { $as_echo "$as_me:${as_lineno-$LINENO}: checking for assembler and linker STT_GNU_IFUNC support" >&5 $as_echo_n "checking for assembler and linker STT_GNU_IFUNC support... " >&6; } @@ -4037,7 +4051,7 @@ __start: EOF libc_cv_ld_gnu_indirect_function=no if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \ - -nostartfiles -nostdlib \ + -nostartfiles -nostdlib $no_ssp \ -o conftest conftest.S 1>&5 2>&5; then # Do a link to see if the backend supports IFUNC relocs. $READELF -r conftest 1>&5 @@ -5532,7 +5546,7 @@ extern int glibc_conftest_frobozz; void _start() { glibc_conftest_frobozz = 1; } EOF if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \ - -nostartfiles -nostdlib \ + -nostartfiles -nostdlib $no_ssp \ -o conftest conftest.s conftest1.c 1>&5 2>&5; then libc_cv_asm_set_directive=yes else @@ -5556,7 +5570,7 @@ else int bar __attribute__ ((visibility ("protected"))) = 1; EOF libc_cv_protected_data=no - if { ac_try='${CC-cc} -nostdlib -nostartfiles -fPIC -shared conftest.c -o conftest.so' + if { ac_try='${CC-cc} -nostdlib -nostartfiles $no_ssp -fPIC -shared conftest.c -o conftest.so' { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 (eval $ac_try) 2>&5 ac_status=$? @@ -5566,7 +5580,7 @@ EOF extern int bar; int main (void) { return bar; } EOF - if { ac_try='${CC-cc} -nostdlib -nostartfiles conftest.c -o conftest conftest.so' + if { ac_try='${CC-cc} -nostdlib -nostartfiles $no_ssp conftest.c -o conftest conftest.so' { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 (eval $ac_try) 2>&5 ac_status=$? @@ -5651,7 +5665,7 @@ __attribute__ ((constructor)) void ctor (void) { asm (""); } __attribute__ ((destructor)) void dtor (void) { asm (""); } EOF -if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -o conftest +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -o conftest conftest.c -static -nostartfiles -nostdlib 1>&5' { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 @@ -5764,7 +5778,7 @@ extern int mumble; int foo (void) { return bar (mumble); } EOF if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS - -fPIC -shared -o conftest.so conftest.c + -fPIC -shared $no_ssp -o conftest.so conftest.c -nostdlib -nostartfiles -Wl,-z,combreloc 1>&5' { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 @@ -5800,7 +5814,7 @@ if test x"$gnu_ld" = x"yes"; then cat > conftest.c <&5' @@ -5854,7 +5868,7 @@ else cat > conftest.c <&5' { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 @@ -5947,7 +5961,7 @@ int foo (void) { return mumble; } EOF if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -fPIC -shared -o conftest.so conftest.c - -nostdlib -nostartfiles + -nostdlib -nostartfiles $no_ssp 1>&5' { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 (eval $ac_try) 2>&5 @@ -5975,7 +5989,7 @@ if ${libc_cv_output_format+:} false; then : $as_echo_n "(cached) " >&6 else if libc_cv_output_format=` -${CC-cc} -nostartfiles -nostdlib -Wl,--print-output-format 2>&5` +${CC-cc} -nostartfiles -nostdlib $no_ssp -Wl,--print-output-format 2>&5` then : else @@ -6453,60 +6467,6 @@ if test $libc_cv_predef_fortify_source = yes; then fi -{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC implicitly enables -fstack-protector" >&5 -$as_echo_n "checking whether $CC implicitly enables -fstack-protector... " >&6; } -if ${libc_cv_predef_stack_protector+:} false; then : - $as_echo_n "(cached) " >&6 -else - -cat confdefs.h - <<_ACEOF >conftest.$ac_ext -/* end confdefs.h. */ -extern void foobar (char *); -int -main () -{ -char large_array[2048]; foobar (large_array); - ; - return 0; -} -_ACEOF -if ac_fn_c_try_compile "$LINENO"; then : - -libc_undefs=`$NM -u conftest.o | - LC_ALL=C $AWK '$1 == "U" { print $2 | "sort -u"; next } { exit(1) }' \ - 2>&5` || { - as_fn_error $? "confusing output from $NM -u" "$LINENO" 5 -} -echo >&5 "libc_undefs='$libc_undefs'" -# On some architectures, there are architecture-specific undefined -# symbols (resolved by the linker), so filter out unknown symbols. -# This will fail to produce the correct result if the compiler -# defaults to -fstack-protector but this produces an undefined symbol -# other than __stack_chk_fail or __stack_chk_fail_local. However, -# compilers like that have not been encountered in practice. -libc_undefs=`echo "$libc_undefs" | \ - egrep '^(foobar|__stack_chk_fail|__stack_chk_fail_local)$'` -case "$libc_undefs" in -foobar) libc_cv_predef_stack_protector=no ;; -'__stack_chk_fail -foobar'|'__stack_chk_fail_local -foobar') libc_cv_predef_stack_protector=yes ;; -*) as_fn_error $? "unexpected symbols in test: $libc_undefs" "$LINENO" 5 ;; -esac -else - as_fn_error $? "test compilation failed" "$LINENO" 5 -fi -rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext - -fi -{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_predef_stack_protector" >&5 -$as_echo "$libc_cv_predef_stack_protector" >&6; } -libc_extra_cflags= -if test $libc_cv_predef_stack_protector = yes; then - libc_extra_cflags="$libc_extra_cflags -fno-stack-protector" -fi -libc_extra_cppflags= - # Some linkers on some architectures support __ehdr_start but with # bugs. Make sure usage of it does not create relocations in the # output (as the linker should resolve them all for us). @@ -6520,7 +6480,7 @@ old_CFLAGS="$CFLAGS" old_LDFLAGS="$LDFLAGS" old_LIBS="$LIBS" CFLAGS="$CFLAGS -fPIC" -LDFLAGS="$LDFLAGS -nostdlib -nostartfiles -shared" +LDFLAGS="$LDFLAGS -nostdlib -nostartfiles -shared $no_ssp" LIBS= cat confdefs.h - <<_ACEOF >conftest.$ac_ext /* end confdefs.h. */ -- cgit v1.1