thomasko wrote:If I only compile kernel with PT_PAX_FLAGS, all programs that haven't been built with patched binutils won't be protected by default?
correct.
And actually they can not be protected under such kernel at all?
not until they get a PT_PAX_FLAGS marking or you also enable the old EI_PAX marking support. for the former, your current option is to recreate the apps with the patched binutils but work is in progress to directly inject this new program header into an ELF file so you can more easily migrate your userland. in my opinion the best migration plan (when you want to switch to PT_PAX_FLAGS at all, that is) is to enable both marking support and use the patched binutils for future compilations (that is, when you're building your userland yourself, it's much easier when a distribution does the work for you, like Hardened Gentoo and maybe Adamantix in the future).
Is there any chance that upstream developers will accept binutils patch?
i never asked but my bet is that it's out of question, this marking is highly specific to PaX. what distributions do is another question of course, i know that Gentoo has incorporated it already.