Date: Thu, 18 Feb 2016 13:46:38 +0100 From: Ard Biesheuvel <ard.biesheuvel@...aro.org> To: Arnd Bergmann <arnd@...db.de> Cc: PaX Team <pageexec@...email.hu>, Laura Abbott <labbott@...hat.com>, Kees Cook <keescook@...omium.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Mark Rutland <mark.rutland@....com>, Jeremy Linton <jeremy.linton@....com>, "kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] lkdtm: add test for executing .rodata On 18 February 2016 at 13:07, Arnd Bergmann <arnd@...db.de> wrote: > On Thursday 18 February 2016 12:34:50 Ard Biesheuvel wrote: >> >> We have __section() as an alias for __attribute__((__section__())), so >> we could use that instead. >> >> However, that does not fix the issue Kees is trying to solve, where a >> .rodata section is emitted with the "x" bit set, which causes the >> linker to complain: >> >> /tmp/cc50ffWw.s: Assembler messages: >> /tmp/cc50ffWw.s:2: Warning: setting incorrect section attributes for >> .rodata.text >> >> I wonder if we could get away with doing something like >> >> AFLAGS_lkdtm.o += -Wa,-W >> >> here? This just hides the warnings, but may result in the .rodata >> section in the vmlinux file to have X permissions as well. I don't >> think anyone uses an ELF loader to load their kernel, but who knows >> ... > > Don't we also get a warning when we link objects with conflicting > section attributes? > I didn't see one > Maybe a solution would be to define a separate section for this one > function, and then use a linker script to move it into .rodata? > Or maybe "objcopy --set-section-flags --rename-section"? > I think objcopy is the easiest.
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