scanner: avoid executable stack

Before this patch:
$ scanelf -lpqe ./wayland-scanner
RWX --- ---  ./wayland-scanner

That indicates the stack is executable, which is a bad thing for
security. Wayland-scanner does not actually need an executable stack, it
is just an oversight from using an .S file in the sources.

Add a special incantation in dtddata.S to make it not cause the stack to
become executable.

Reported-by: Mart Raudsepp <leio@gentoo.org>
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Tested-by: Mart Raudsepp <leio@gentoo.org>

diff --git a/src/dtddata.S b/src/dtddata.S
index 68e3435..ce51133 100644 (file)
--- a/src/dtddata.S
+++ b/src/dtddata.S
@@ -20,6 +20,14 @@
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+/*
+ * Avoid executable stack.
+ * from: https://wiki.gentoo.org/wiki/Hardened/GNU_stack_quickstart
+ */
+#if defined(__linux__) && defined(__ELF__)
+.section .note.GNU-stack,"",%progbits
+#endif
+
 /* from: http://www.linuxjournal.com/content/embedding-file-executable-aka-hello-world-version-5967#comment-348129 */
 
 .macro binfile name file