From: Kees Cook <keescook@chromium.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
stable@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Nathan Chancellor <nathan@kernel.org>
Subject: Re: [PATCH] lkdtm: Fix content of section containing lkdtm_rodata_do_nothing()
Date: Fri, 8 Oct 2021 14:16:19 -0700 [thread overview]
Message-ID: <202110081415.E36B67FA@keescook> (raw)
In-Reply-To: <CAKwvOdnWbKdBuSGtmu2DURy5dtVGUYWJ_mwxSL6N5OfbmjU3EA@mail.gmail.com>
On Fri, Oct 08, 2021 at 11:09:47AM -0700, Nick Desaulniers wrote:
> On Fri, Oct 8, 2021 at 9:59 AM Christophe Leroy
> <christophe.leroy@csgroup.eu> wrote:
> >
> > On a kernel without CONFIG_STRICT_KERNEL_RWX, running EXEC_RODATA
> > test leads to "Illegal instruction" failure.
> >
> > Looking at the content of rodata_objcopy.o, we see that the
> > function content zeroes only:
> >
> > Disassembly of section .rodata:
> >
> > 0000000000000000 <.lkdtm_rodata_do_nothing>:
> > 0: 00 00 00 00 .long 0x0
> >
> > Add the contents flag in order to keep the content of the section
> > while renaming it.
> >
> > Disassembly of section .rodata:
> >
> > 0000000000000000 <.lkdtm_rodata_do_nothing>:
> > 0: 4e 80 00 20 blr
> >
> > Fixes: e9e08a07385e ("lkdtm: support llvm-objcopy")
>
> Thanks for the patch; sorry I broke this.
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Hah! Whoops; sorry I don't have an inverted version of this test! I
should have caught this when it broke. :|
-Kees
--
Kees Cook
next prev parent reply other threads:[~2021-10-08 21:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-08 16:58 [PATCH] lkdtm: Fix content of section containing lkdtm_rodata_do_nothing() Christophe Leroy
2021-10-08 18:09 ` Nick Desaulniers
2021-10-08 21:16 ` Kees Cook [this message]
2021-10-08 21:17 ` Kees Cook
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