Fixed bug 4308 - Prebuilt SDL.dll files not compiled with ASLR support (DYNAMICBASE)
Cameron Gutman
The current SDL 2.0.8 and the prerelease SDL 2.0.9 are compiled without the DYNAMICBASE flag to indicate that ASLR may relocate the DLL at load-time. https://docs.microsoft.com/en-us/cpp/build/reference/dynamicbase-use-address-space-layout-randomization?view=vs-2017
When I build SDL.dll myself using the VS2010 project, the DLL has the DYNAMICBASE flag set (as is the default). Similarly, MinGW-w64 also enables ASLR by default on all binaries for a couple years now (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=836365)
diff --git a/configure b/configure
index aee0cb6..db15105 100755
--- a/configure
+++ b/configure
@@ -16063,6 +16063,108 @@
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $have_no_undefined" >&5
$as_echo "$have_no_undefined" >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker option --dynamicbase" >&5
+$as_echo_n "checking for linker option --dynamicbase... " >&6; }
+have_dynamicbase=no
+case "$host" in
+ *)
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$LDFLAGS -Wl,--dynamicbase"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+
+int
+main ()
+{
+
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+ have_dynamicbase=yes
+ EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,--dynamicbase"
+
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ LDFLAGS="$save_LDFLAGS"
+ ;;
+esac
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $have_dynamicbase" >&5
+$as_echo "$have_dynamicbase" >&6; }
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker option --nxcompat" >&5
+$as_echo_n "checking for linker option --nxcompat... " >&6; }
+have_nxcompat=no
+case "$host" in
+ *)
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$LDFLAGS -Wl,--nxcompat"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+
+int
+main ()
+{
+
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+ have_nxcompat=yes
+ EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,--nxcompat"
+
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ LDFLAGS="$save_LDFLAGS"
+ ;;
+esac
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $have_nxcompat" >&5
+$as_echo "$have_nxcompat" >&6; }
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker option --high-entropy-va" >&5
+$as_echo_n "checking for linker option --high-entropy-va... " >&6; }
+have_high_entropy_va=no
+case "$host" in
+ *)
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$LDFLAGS -Wl,--high-entropy-va"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+
+int
+main ()
+{
+
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+ have_high_entropy_va=yes
+ EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,--high-entropy-va"
+
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ LDFLAGS="$save_LDFLAGS"
+ ;;
+esac
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $have_high_entropy_va" >&5
+$as_echo "$have_high_entropy_va" >&6; }
+
# Check whether --enable-libc was given.
if test "${enable_libc+set}" = set; then :
enableval=$enable_libc;
diff --git a/configure.in b/configure.in
index ae866ff..91b45d3 100644
--- a/configure.in
+++ b/configure.in
@@ -232,6 +232,57 @@
esac
AC_MSG_RESULT($have_no_undefined)
+AC_MSG_CHECKING(for linker option --dynamicbase)
+have_dynamicbase=no
+case "$host" in
+ *)
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$LDFLAGS -Wl,--dynamicbase"
+ AC_TRY_LINK([
+ ],[
+ ],[
+ have_dynamicbase=yes
+ EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,--dynamicbase"
+ ])
+ LDFLAGS="$save_LDFLAGS"
+ ;;
+esac
+AC_MSG_RESULT($have_dynamicbase)
+
+AC_MSG_CHECKING(for linker option --nxcompat)
+have_nxcompat=no
+case "$host" in
+ *)
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$LDFLAGS -Wl,--nxcompat"
+ AC_TRY_LINK([
+ ],[
+ ],[
+ have_nxcompat=yes
+ EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,--nxcompat"
+ ])
+ LDFLAGS="$save_LDFLAGS"
+ ;;
+esac
+AC_MSG_RESULT($have_nxcompat)
+
+AC_MSG_CHECKING(for linker option --high-entropy-va)
+have_high_entropy_va=no
+case "$host" in
+ *)
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$LDFLAGS -Wl,--high-entropy-va"
+ AC_TRY_LINK([
+ ],[
+ ],[
+ have_high_entropy_va=yes
+ EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,--high-entropy-va"
+ ])
+ LDFLAGS="$save_LDFLAGS"
+ ;;
+esac
+AC_MSG_RESULT($have_high_entropy_va)
+
dnl See whether we are allowed to use the system C library
AC_ARG_ENABLE(libc,
AC_HELP_STRING([--enable-libc], [Use the system C library [[default=yes]]]),
