Hash :
a6c07234
Author :
Date :
2014-12-23T05:24:24
configure.ac: use executable hardening where available Where available, enable stack smashing protection, fortify source, no-strict-overflow, and read only relocations. Many Linux distributions automatically enable most of these options. They are no brainers. The difference introduced here is in asking for a few more aggressive options. An option to disable the more aggressive options is provided (--disable-hardening). When set, configure will fall back to the default CFLAGS on the system - in many cases that will still be hardened. There is no point in going further than that. Options enabled are: -fstack-protector-strong is a relatively new GCC-4.9 feature that is supposed to give a better balance between performance and protection. -all is considered too aggressive, but was used in Chromium and other security critical systems until -strong became available. Follow their lead and use -strong when possible. clang 6.0 supports -all but not -strong. _FORTIFY_SOURCE replaces certain unsafe C str* and mem* functions with more robust equivalents when the compiler can determine the length of the buffers involved. -fno-strict-overflow instructs GCC to not make optimizations based on the assumption that signed arithmetic will wrap around on overflow (e.g. (short)0x7FFF + 1 == 0). This prevents the optimizer from doing some unexpected things. Further improvements should trap signed overflows and reduce the use of signed to refer to naturally unsigned quantities. I did not set -fPIE (position independent executables). The critical function of Open/LibreSSL is as a library, not an executable. Tested on Ubuntu Linux 14.04.1 LTS, OS X 10.10.1 with "make check". Signed-off-by: Jim Barlow <jim@purplerock.ca>
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AC_INIT([libressl], m4_esyscmd([tr -d '\n' < VERSION]))
AC_SUBST([LIBCRYPTO_VERSION], m4_esyscmd([tr -d '\n' < crypto/VERSION]))
AC_SUBST([LIBSSL_VERSION], m4_esyscmd([tr -d '\n' < ssl/VERSION]))
AC_SUBST([LIBTLS_VERSION], m4_esyscmd([tr -d '\n' < tls/VERSION]))
AC_CANONICAL_HOST
AM_INIT_AUTOMAKE([subdir-objects])
AC_CONFIG_MACRO_DIR([m4])
m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
AC_SUBST([USER_CFLAGS], "-O2 $CFLAGS")
CFLAGS="$CFLAGS -Wall -std=gnu99 -g"
case $host_os in
*darwin*)
HOST_OS=darwin
HOST_ABI=macosx
;;
*freebsd*)
HOST_OS=freebsd
HOST_ABI=elf
AC_SUBST([PROG_LDADD], ['-lthr'])
;;
*linux*)
HOST_OS=linux
HOST_ABI=elf
CFLAGS="$CFLAGS -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_SOURCE -D_GNU_SOURCE"
;;
*openbsd*)
HOST_ABI=elf
AC_DEFINE([HAVE_ATTRIBUTE__BOUNDED__], [1], [OpenBSD gcc has bounded])
;;
*mingw*)
HOST_OS=win
CFLAGS="$CFLAGS -D_GNU_SOURCE -D_POSIX -D_POSIX_SOURCE -D_REENTRANT -D_POSIX_THREAD_SAFE_FUNCTIONS -DWIN32_LEAN_AND_MEAN -D_WIN32_WINNT=0x0600 -DOPENSSL_NO_SPEED -DNO_SYSLOG -D__USE_MINGW_ANSI_STDIO"
AC_SUBST([PLATFORM_LDADD], ['-lws2_32'])
;;
*solaris*)
HOST_OS=solaris
HOST_ABI=elf
CFLAGS="$CFLAGS -D__EXTENSIONS__ -D_XOPEN_SOURCE=600 -DBSD_COMP"
AC_SUBST([PLATFORM_LDADD], ['-lnsl -lsocket'])
;;
*) ;;
esac
AM_CONDITIONAL([HOST_DARWIN], [test x$HOST_OS = xdarwin])
AM_CONDITIONAL([HOST_FREEBSD], [test x$HOST_OS = xfreebsd])
AM_CONDITIONAL([HOST_LINUX], [test x$HOST_OS = xlinux])
AM_CONDITIONAL([HOST_SOLARIS], [test x$HOST_OS = xsolaris])
AM_CONDITIONAL([HOST_WIN], [test x$HOST_OS = xwin])
AC_CHECK_FUNC([clock_gettime],,
[AC_SEARCH_LIBS([clock_gettime],[rt posix4])])
AC_CHECK_FUNC([dl_iterate_phdr],,
[AC_SEARCH_LIBS([dl_iterate_phdr],[dl])])
AM_PROG_AS
AC_PROG_CC
AC_PROG_LIBTOOL
AC_PROG_CC_STDC
AM_PROG_CC_C_O
AC_MSG_CHECKING([if compiling with clang])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[
#ifndef __clang__
not clang
#endif
]])],
[CLANG=yes],
[CLANG=no]
)
AC_MSG_RESULT([CLANG])
# We want to check for compiler flag support, but there is no way to make
# clang's "argument unused" warning fatal. So we invoke the compiler through a
# wrapper script that greps for this message.
saved_CC="$CC"
saved_LD="$LD"
flag_wrap="$srcdir/scripts/wrap-compiler-for-flag-check"
CC="$flag_wrap $CC"
LD="$flag_wrap $LD"
AC_DEFUN([check_cflag],
[AX_CHECK_COMPILE_FLAG([$1], [$2], [$3], [-Werror $4])])
AC_DEFUN([check_ldflag],
[AX_CHECK_LINK_FLAG([$1], [$2], [$3], [-Werror $4])])
AC_ARG_ENABLE([hardening],
[AS_HELP_STRING([--disable-hardening], [Disable options to frustrate memory corruption exploits])],
[],
[enable_hardening=yes])
HARDEN_CFLAGS=""
HARDEN_LDFLAGS=""
AS_IF([test "x$enable_hardening" == "xyes"], [
# Tell GCC to NOT optimize based on signed arithmetic overflow
check_cflag([-fno-strict-overflow], [HARDEN_CFLAGS="$HARDEN_CFLAGS -fno-strict-overflow"])
# _FORTIFY_SOURCE replaces builtin functions with safer versions.
check_cflag([-D_FORTIFY_SOURCE=2],
[HARDEN_CFLAGS="$HARDEN_CFLAGS -D_FORTIFY_SOURCE=2"])
# Use stack-protector-strong if available; if not, fallback to stack-protector-all which
# is considered to be overkill
check_cflag([-fstack-protector-strong],
[STACK_PROTECT="-fstack-protector-strong"],
check_cflag([-fstack-protector-all],
[STACK_PROTECT="-fstack-protector-all"],
[AC_MSG_ERROR([compiler does not support stack protection - use --disable-hardening to override if you understand the risks])]
)
)
check_ldflag([$STACK_PROTECT],
[HARDEN_CFLAGS="$HARDEN_CFLAGS $STACK_PROTECT"
check_cflag([-Wstack-protector], [HARDEN_CFLAGS="$HARDEN_CFLAGS -Wstack-protector"],
[], [$STACK_PROTECT])
],
[AC_MSG_ERROR([compiler supports stack protection but linker does not])]
)
# Enable read only relocations
check_ldflag([-Wl,-z,relro],
[HARDEN_LDFLAGS="$HARDEN_LDFLAGS -Wl,-z,relro"
check_ldflag([-Wl,-z,now], [HARDEN_LDFLAGS="$HARDEN_LDFLAGS -Wl,-z,now"])])
])
# Restore CC, LD
CC="$saved_CC"
LD="$saved_LD"
CFLAGS="$CFLAGS $HARDEN_CFLAGS"
LDFLAGS="$LDFLAGS $HARDEN_LDFLAGS"
# Removing the dependency on -Wno-pointer-sign should be a goal
save_cflags="$CFLAGS"
CFLAGS=-Wno-pointer-sign
AC_MSG_CHECKING([whether CC supports -Wno-pointer-sign])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])],
[AC_MSG_RESULT([yes])]
[AM_CFLAGS=-Wno-pointer-sign],
[AC_MSG_RESULT([no])]
)
CFLAGS="$save_cflags $AM_CFLAGS"
# TODO: note CFLAGS=...CLANG_CFLAGS has no effect since the latter is undefined
# investigate its effect
AS_IF([test "x$CLANG" == "xyes"], [CLANG_FLAGS=-Qunused-arguments])
CFLAGS="$CFLAGS $CLANG_CFLAGS"
LDFLAGS="$LDFLAGS $CLANG_FLAGS"
AC_CHECK_FUNCS([arc4random_buf asprintf explicit_bzero funopen getauxval])
AC_CHECK_FUNCS([getentropy issetugid memmem poll reallocarray])
AC_CHECK_FUNCS([strlcat strlcpy strndup strnlen strtonum])
AC_CHECK_FUNCS([timingsafe_bcmp timingsafe_memcmp])
# Share test results with automake
AM_CONDITIONAL([HAVE_ARC4RANDOM_BUF], [test "x$ac_cv_func_arc4random_buf" = xyes])
AM_CONDITIONAL([HAVE_ASPRINTF], [test "x$ac_cv_func_asprintf" = xyes])
AM_CONDITIONAL([HAVE_EXPLICIT_BZERO], [test "x$ac_cv_func_explicit_bzero" = xyes])
AM_CONDITIONAL([HAVE_GETENTROPY], [test "x$ac_cv_func_getentropy" = xyes])
AM_CONDITIONAL([HAVE_ISSETUGID], [test "x$ac_cv_func_issetugid" = xyes])
AM_CONDITIONAL([HAVE_MEMMEM], [test "x$ac_cv_func_memmem" = xyes])
AM_CONDITIONAL([HAVE_POLL], [test "x$ac_cv_func_poll" = xyes])
AM_CONDITIONAL([HAVE_REALLOCARRAY], [test "x$ac_cv_func_reallocarray" = xyes])
AM_CONDITIONAL([HAVE_STRLCAT], [test "x$ac_cv_func_strlcat" = xyes])
AM_CONDITIONAL([HAVE_STRLCPY], [test "x$ac_cv_func_strlcpy" = xyes])
AM_CONDITIONAL([HAVE_STRNDUP], [test "x$ac_cv_func_strndup" = xyes])
AM_CONDITIONAL([HAVE_STRNLEN], [test "x$ac_cv_func_strnlen" = xyes])
AM_CONDITIONAL([HAVE_STRTONUM], [test "x$ac_cv_func_strtonum" = xyes])
AM_CONDITIONAL([HAVE_TIMINGSAFE_BCMP], [test "x$ac_cv_func_timingsafe_bcmp" = xyes])
AM_CONDITIONAL([HAVE_TIMINGSAFE_MEMCMP], [test "x$ac_cv_func_timingsafe_memcmp" = xyes])
# overrides for arc4random_buf implementations with known issues
AM_CONDITIONAL([HAVE_ARC4RANDOM_BUF],
[test "x$HOST_OS" != xdarwin -a "x$HOST_OS" != xfreebsd -a "x$ac_cv_func_arc4random_buf" = xyes])
AC_CACHE_CHECK([whether va_copy exists], ac_cv_have_va_copy, [
AC_LINK_IFELSE([AC_LANG_PROGRAM([[
#include <stdarg.h>
va_list x,y;
]], [[ va_copy(x,y); ]])],
[ ac_cv_have_va_copy="yes" ],
[ ac_cv_have_va_copy="no"
])
])
if test "x$ac_cv_have_va_copy" = "xyes" ; then
AC_DEFINE([HAVE_VA_COPY], [1], [Define if va_copy exists])
fi
AC_CACHE_CHECK([whether __va_copy exists], ac_cv_have___va_copy, [
AC_LINK_IFELSE([AC_LANG_PROGRAM([[
#include <stdarg.h>
va_list x,y;
]], [[ __va_copy(x,y); ]])],
[ ac_cv_have___va_copy="yes" ], [ ac_cv_have___va_copy="no"
])
])
if test "x$ac_cv_have___va_copy" = "xyes" ; then
AC_DEFINE([HAVE___VA_COPY], [1], [Define if __va_copy exists])
fi
AC_CHECK_HEADERS([sys/sysctl.h err.h])
AC_ARG_WITH([openssldir],
AS_HELP_STRING([--with-openssldir],
[Set the default openssl directory]),
AC_DEFINE_UNQUOTED(OPENSSLDIR, "$withval")
)
AC_ARG_WITH([enginesdir],
AS_HELP_STRING([--with-enginesdir],
[Set the default engines directory (use with openssldir)]),
AC_DEFINE_UNQUOTED(ENGINESDIR, "$withval")
)
AC_ARG_ENABLE([asm],
AS_HELP_STRING([--disable-asm], [Disable assembly]))
AM_CONDITIONAL([OPENSSL_NO_ASM], [test "x$enable_asm" = "xno"])
AM_CONDITIONAL([HOST_ASM_ELF_X86_64],
[test "x$HOST_ABI" = "xelf" -a "$host_cpu" = "x86_64" -a "x$enable_asm" != "xno"])
AM_CONDITIONAL([HOST_ASM_MACOSX_X86_64],
[test "x$HOST_ABI" = "xmacosx" -a "$host_cpu" = "x86_64" -a "x$enable_asm" != "xno"])
AC_ARG_ENABLE([libtls],
AS_HELP_STRING([--enable-libtls], [Enable building the libtls library]))
AM_CONDITIONAL([ENABLE_LIBTLS], [test "x$enable_libtls" = xyes])
AM_COND_IF([ENABLE_LIBTLS], [AC_CONFIG_FILES([libtls.pc])])
LT_INIT
AC_CONFIG_FILES([
Makefile
include/Makefile
include/openssl/Makefile
crypto/Makefile
ssl/Makefile
tls/Makefile
tests/Makefile
apps/Makefile
man/Makefile
libcrypto.pc
libssl.pc
openssl.pc
])
AC_OUTPUT