As promised in the --enable-host-pie patch, this patch adds another
configure option, --enable-host-bind-now, which adds -z now when linking
the compiler executables in order to extend hardening. BIND_NOW with RELRO
allows the GOT to be marked RO; this prevents GOT modification attacks.
This option does not affect linking of target libraries; you can use
LDFLAGS_FOR_TARGET=-Wl,-z,relro,-z,now to enable RELRO/BIND_NOW.
Bootstrapped/regtested on x86_64-pc-linux-gnu (with the option enabled vs
not enabled). I suppose this is GCC 13 material, but maybe I'll get some
comments anyway.
c++tools/ChangeLog:
* configure.ac (--enable-host-bind-now): New check.
* configure: Regenerate.
gcc/ChangeLog:
* configure.ac (--enable-host-bind-now): New check. Add
-Wl,-z,now to LD_PICFLAG if --enable-host-bind-now.
* configure: Regenerate.
* doc/install.texi: Document --enable-host-bind-now.
lto-plugin/ChangeLog:
* configure.ac (--enable-host-bind-now): New check. Link with
-z,now.
* configure: Regenerate.
---
c++tools/configure | 11 +++++++++++
c++tools/configure.ac | 7 +++++++
gcc/configure | 20 ++++++++++++++++++--
gcc/configure.ac | 13 ++++++++++++-
gcc/doc/install.texi | 6 ++++++
lto-plugin/configure | 20 ++++++++++++++++++--
lto-plugin/configure.ac | 11 +++++++++++
7 files changed, 83 insertions(+), 5 deletions(-)
base-commit: bf799d3409cb9a189114a6c9ff5b7cd123915764
@@ -628,6 +628,7 @@ EGREP
GREP
CXXCPP
LD_PICFLAG
+enable_host_bind_now
PICFLAG
MAINTAINER
CXX_AUX_TOOLS
@@ -702,6 +703,7 @@ enable_maintainer_mode
enable_checking
enable_default_pie
enable_host_pie
+enable_host_bind_now
with_gcc_major_version_only
'
ac_precious_vars='build_alias
@@ -1336,6 +1338,7 @@ Optional Features:
yes,no,all,none,release.
--enable-default-pie enable Position Independent Executable as default
--enable-host-pie build host code as PIE
+ --enable-host-bind-now link host code as BIND_NOW
Optional Packages:
--with-PACKAGE[=ARG] use PACKAGE [ARG=yes]
@@ -3007,6 +3010,14 @@ fi
+# Enable --enable-host-bind-now
+# Check whether --enable-host-bind-now was given.
+if test "${enable_host_bind_now+set}" = set; then :
+ enableval=$enable_host_bind_now; LD_PICFLAG="$LD_PICFLAG -Wl,-z,now"
+fi
+
+
+
# Check if O_CLOEXEC is defined by fcntl
@@ -110,6 +110,13 @@ AC_ARG_ENABLE(host-pie,
[build host code as PIE])],
[PICFLAG=-fPIE; LD_PICFLAG=-pie], [])
AC_SUBST(PICFLAG)
+
+# Enable --enable-host-bind-now
+AC_ARG_ENABLE(host-bind-now,
+[AS_HELP_STRING([--enable-host-bind-now],
+ [link host code as BIND_NOW])],
+[LD_PICFLAG="$LD_PICFLAG -Wl,-z,now"], [])
+AC_SUBST(enable_host_bind_now)
AC_SUBST(LD_PICFLAG)
# Check if O_CLOEXEC is defined by fcntl
@@ -635,6 +635,7 @@ CET_HOST_FLAGS
LD_PICFLAG
PICFLAG
enable_default_pie
+enable_host_bind_now
enable_host_pie
enable_host_shared
enable_plugin
@@ -1026,6 +1027,7 @@ enable_version_specific_runtime_libs
enable_plugin
enable_host_shared
enable_host_pie
+enable_host_bind_now
enable_libquadmath_support
with_linker_hash_style
with_diagnostics_color
@@ -1789,6 +1791,7 @@ Optional Features:
--enable-plugin enable plugin support
--enable-host-shared build host code as shared libraries
--enable-host-pie build host code as PIE
+ --enable-host-bind-now link host code as BIND_NOW
--disable-libquadmath-support
disable libquadmath support for Fortran
--enable-default-pie enable Position Independent Executable as default
@@ -19661,7 +19664,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 19676 "configure"
+#line 19679 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -19767,7 +19770,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 19782 "configure"
+#line 19785 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -32236,6 +32239,14 @@ fi
+# Enable --enable-host-bind-now
+# Check whether --enable-host-bind-now was given.
+if test "${enable_host_bind_now+set}" = set; then :
+ enableval=$enable_host_bind_now;
+fi
+
+
+
# Check whether --enable-libquadmath-support was given.
if test "${enable_libquadmath_support+set}" = set; then :
enableval=$enable_libquadmath_support; ENABLE_LIBQUADMATH_SUPPORT=$enableval
@@ -32422,6 +32433,8 @@ else
PICFLAG=
fi
+
+
if test x$enable_host_pie = xyes; then
LD_PICFLAG=-pie
elif test x$gcc_cv_no_pie = xyes; then
@@ -32430,6 +32443,9 @@ else
LD_PICFLAG=
fi
+if test x$enable_host_bind_now = xyes; then
+ LD_PICFLAG="$LD_PICFLAG -Wl,-z,now"
+fi
@@ -7497,6 +7497,12 @@ AC_ARG_ENABLE(host-pie,
[build host code as PIE])])
AC_SUBST(enable_host_pie)
+# Enable --enable-host-bind-now
+AC_ARG_ENABLE(host-bind-now,
+[AS_HELP_STRING([--enable-host-bind-now],
+ [link host code as BIND_NOW])])
+AC_SUBST(enable_host_bind_now)
+
AC_ARG_ENABLE(libquadmath-support,
[AS_HELP_STRING([--disable-libquadmath-support],
[disable libquadmath support for Fortran])],
@@ -7638,6 +7644,8 @@ else
PICFLAG=
fi
+AC_SUBST([PICFLAG])
+
if test x$enable_host_pie = xyes; then
LD_PICFLAG=-pie
elif test x$gcc_cv_no_pie = xyes; then
@@ -7646,7 +7654,10 @@ else
LD_PICFLAG=
fi
-AC_SUBST([PICFLAG])
+if test x$enable_host_bind_now = xyes; then
+ LD_PICFLAG="$LD_PICFLAG -Wl,-z,now"
+fi
+
AC_SUBST([LD_PICFLAG])
# Enable Intel CET on Intel CET enabled host if jit is enabled.
@@ -1041,6 +1041,12 @@ protection against Return Oriented Programming (ROP) attacks.
in which case @option{-fPIC} is used when compiling, and @option{-pie} when
linking.
+@item --enable-host-bind-now
+Specify that the @emph{host} executables should be linked with the option
+@option{-Wl,-z,now}, which means that the dynamic linker will resolve all
+symbols when the executables are started, and that in turn allows RELRO to
+mark the GOT read-only, resulting in better security.
+
@item @anchor{with-gnu-as}--with-gnu-as
Specify that the compiler should assume that the
assembler it finds is the GNU assembler. However, this does not modify
@@ -656,6 +656,7 @@ accel_dir_suffix
gcc_build_dir
CET_HOST_FLAGS
ac_lto_plugin_ldflags
+enable_host_bind_now
ac_lto_plugin_warn_cflags
EGREP
GREP
@@ -771,6 +772,7 @@ enable_maintainer_mode
with_libiberty
enable_dependency_tracking
enable_largefile
+enable_host_bind_now
enable_cet
with_gcc_major_version_only
enable_shared
@@ -1418,6 +1420,7 @@ Optional Features:
--disable-dependency-tracking
speeds up one-time build
--disable-largefile omit support for large files
+ --enable-host-bind-now link host code as BIND_NOW
--enable-cet enable Intel CET in host libraries [default=auto]
--enable-shared[=PKGS] build shared libraries [default=yes]
--enable-static[=PKGS] build static libraries [default=yes]
@@ -5662,6 +5665,19 @@ if test "x$have_static_libgcc" = xyes; then
ac_lto_plugin_ldflags="-Wc,-static-libgcc"
fi
+# Enable --enable-host-bind-now
+# Check whether --enable-host-bind-now was given.
+if test "${enable_host_bind_now+set}" = set; then :
+ enableval=$enable_host_bind_now;
+fi
+
+
+
+if test x$enable_host_bind_now = xyes; then
+ ac_lto_plugin_ldflags="$ac_lto_plugin_ldflags -Wl,-z,now"
+fi
+
+
# Check whether --enable-cet was given.
if test "${enable_cet+set}" = set; then :
@@ -11981,7 +11997,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 11984 "configure"
+#line 12012 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -12087,7 +12103,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 12090 "configure"
+#line 12118 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -25,6 +25,17 @@ LDFLAGS="$saved_LDFLAGS"
if test "x$have_static_libgcc" = xyes; then
ac_lto_plugin_ldflags="-Wc,-static-libgcc"
fi
+
+# Enable --enable-host-bind-now
+AC_ARG_ENABLE(host-bind-now,
+[AS_HELP_STRING([--enable-host-bind-now],
+ [link host code as BIND_NOW])])
+AC_SUBST(enable_host_bind_now)
+
+if test x$enable_host_bind_now = xyes; then
+ ac_lto_plugin_ldflags="$ac_lto_plugin_ldflags -Wl,-z,now"
+fi
+
AC_SUBST(ac_lto_plugin_ldflags)
GCC_CET_HOST_FLAGS(CET_HOST_FLAGS)