@@ -302,6 +302,7 @@ audio_win_int=""
libs_qga=""
debug_info="yes"
stack_protector=""
+safe_stack=""
use_containers="yes"
gdb_bin=$(command -v "gdb-multiarch" || command -v "gdb")
@@ -1275,6 +1276,10 @@ for opt do
;;
--disable-stack-protector) stack_protector="no"
;;
+ --enable-safe-stack) safe_stack="yes"
+ ;;
+ --disable-safe-stack) safe_stack="no"
+ ;;
--disable-curses) curses="no"
;;
--enable-curses) curses="yes"
@@ -1804,6 +1809,8 @@ disabled with --disable-FEATURE, default is enabled if available:
debug-tcg TCG debugging (default is disabled)
debug-info debugging information
sparse sparse checker
+ safe-stack SafeStack Stack Smash Protection. Depends on
+ clang/llvm >= 3.7 and requires coroutine backend ucontext.
gnutls GNUTLS cryptography support
nettle nettle cryptography support
@@ -5517,6 +5524,67 @@ if test "$debug_stack_usage" = "yes"; then
fi
fi
+##################################################
+# SafeStack
+
+
+if test "$safe_stack" = "yes"; then
+cat > $TMPC << EOF
+int main(int argc, char *argv[])
+{
+#if ! __has_feature(safe_stack)
+#error SafeStack Disabled
+#endif
+ return 0;
+}
+EOF
+ flag="-fsanitize=safe-stack"
+ # Check that safe-stack is supported and enabled.
+ if compile_prog "-Werror $flag" "$flag"; then
+ # Flag needed both at compilation and at linking
+ QEMU_CFLAGS="$QEMU_CFLAGS $flag"
+ QEMU_LDFLAGS="$QEMU_LDFLAGS $flag"
+ else
+ error_exit "SafeStack not supported by your compiler"
+ fi
+ if test "$coroutine" != "ucontext"; then
+ error_exit "SafeStack is only supported by the coroutine backend ucontext"
+ fi
+else
+cat > $TMPC << EOF
+int main(int argc, char *argv[])
+{
+#if defined(__has_feature)
+#if __has_feature(safe_stack)
+#error SafeStack Enabled
+#endif
+#endif
+ return 0;
+}
+EOF
+if test "$safe_stack" = "no"; then
+ # Make sure that safe-stack is disabled
+ if ! compile_prog "-Werror" ""; then
+ # SafeStack was already enabled, try to explicitly remove the feature
+ flag="-fno-sanitize=safe-stack"
+ if ! compile_prog "-Werror $flag" "$flag"; then
+ error_exit "Configure cannot disable SafeStack"
+ fi
+ QEMU_CFLAGS="$QEMU_CFLAGS $flag"
+ QEMU_LDFLAGS="$QEMU_LDFLAGS $flag"
+ fi
+else # "$safe_stack" = ""
+ # Set safe_stack to yes or no based on pre-existing flags
+ if compile_prog "-Werror" ""; then
+ safe_stack="no"
+ else
+ safe_stack="yes"
+ if test "$coroutine" != "ucontext"; then
+ error_exit "SafeStack is only supported by the coroutine backend ucontext"
+ fi
+ fi
+fi
+fi
##########################################
# check if we have open_by_handle_at
@@ -6611,6 +6679,7 @@ echo "sparse enabled $sparse"
echo "strip binaries $strip_opt"
echo "profiler $profiler"
echo "static build $static"
+echo "safe stack $safe_stack"
if test "$darwin" = "yes" ; then
echo "Cocoa support $cocoa"
fi
@@ -8195,6 +8264,10 @@ if test "$ccache_cpp2" = "yes"; then
echo "export CCACHE_CPP2=y" >> $config_host_mak
fi
+if test "$safe_stack" = "yes"; then
+ echo "CONFIG_SAFESTACK=y" >> $config_host_mak
+fi
+
# If we're using a separate build tree, set it up now.
# DIRS are directories which we simply mkdir in the build tree;
# LINKS are things to symlink back into the source tree
This patch adds a flag to enable/disable the SafeStack instrumentation provided by LLVM. On enable, make sure that the compiler supports the flags, and that we are using the proper coroutine implementation (coroutine-ucontext). On disable, explicitly disable the option if it was enabled by default. While SafeStack is supported only on Linux, NetBSD, FreeBSD and macOS, we are not checking for the O.S. since this is already done by LLVM. Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com> --- configure | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+)