Re: [PATCH net-next] modules: allow modprobe load regular elf binaries
From: Alexei Starovoitov <hidden>
Date: 2018-03-09 01:25:37
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lkml, netdev
On Fri, Mar 09, 2018 at 01:04:39AM +0000, Andy Lutomirski wrote:
On Fri, Mar 9, 2018 at 12:57 AM, Alexei Starovoitov [off-list ref] wrote:quoted
On 3/8/18 4:24 PM, Kees Cook wrote:quoted
As Andy asked earlier, why not DYN too to catch PIE executables? Seems like forcing the userspace helper to be non-PIE would defeat some of the userspace defenses in use in most distros.because we don't add features without concrete users.I disagree here. If you're going to add a magic trick that triggers an execve(), then I think you should either support *both* standard, widely-used types of ELF programs or you should give a compelling use case that works for ET_EXEC but not for ET_DYN. Keep in mind that many distros have a very strong preference for ET_DYN.
misunderstanding here is that this bpfiler.ko is part of _kernel build_. Kernel decides how it's build. Nothing to do with distros. Current Makefile is very dumb and it's built with HOSTCC: https://git.kernel.org/pub/scm/linux/kernel/git/ast/bpf.git/tree/net/bpfilter/Makefile?h=ipt_bpf but it will be standalone with CC before final to make sure crosscompiling works.