From: Michael Ellerman <mpe@ellerman.id.au>
To: Jordan Niethe <jniethe5@gmail.com>, linuxppc-dev@lists.ozlabs.org
Cc: ajd@linux.ibm.com, Kees Cook <keescook@chromium.org>,
Jordan Niethe <jniethe5@gmail.com>,
cmr@codefail.de, npiggin@gmail.com, naveen.n.rao@linux.ibm.com,
dja@axtens.net
Subject: Re: [PATCH v10 06/10] powerpc/mm/ptdump: debugfs handler for W+X checks at runtime
Date: Wed, 31 Mar 2021 22:24:40 +1100 [thread overview]
Message-ID: <87im577eh3.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20210330045132.722243-7-jniethe5@gmail.com>
Jordan Niethe <jniethe5@gmail.com> writes:
> From: Russell Currey <ruscur@russell.cc>
>
> Optionally run W+X checks when dumping pagetable information to
> debugfs' kernel_page_tables.
>
> To use:
> $ echo 1 > /sys/kernel/debug/check_wx_pages
> $ cat /sys/kernel/debug/kernel_page_tables
>
> and check the kernel log. Useful for testing strict module RWX.
>
> To disable W+X checks:
> $ echo 0 > /sys/kernel/debug/check_wx_pages
>
> Update the Kconfig entry to reflect this.
>
> Also fix a typo.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Russell Currey <ruscur@russell.cc>
> [jpn: Change check_wx_pages to act as mode bit affecting
> kernel_page_tables instead of triggering action on its own]
> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
> ---
> v10: check_wx_pages now affects kernel_page_tables rather then triggers
> its own action.
Hmm. I liked the old version better :)
I think you changed it based on Christophe's comment:
Why not just perform the test everytime someone dumps kernel_page_tables ?
But I think he meant *always* do the check when someone dumps
kernel_page_tables, not have another file to enable checking and then
require someone to dump kernel_page_tables to do the actual check.
Still I like the previous version where you can do the checks
separately, without having to dump the page tables, because dumping can
sometimes take quite a while.
What would be even better is if ptdump_check_wx() returned an error when
wx pages were found, and that was plumbed out to the debugs file. That
way you can script around it.
cheers
next prev parent reply other threads:[~2021-03-31 11:25 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-30 4:51 [PATCH v10 00/10] powerpc: Further Strict RWX support Jordan Niethe
2021-03-30 4:51 ` [PATCH v10 01/10] powerpc/mm: Implement set_memory() routines Jordan Niethe
2021-03-30 5:16 ` Christophe Leroy
2021-04-21 2:51 ` Jordan Niethe
2021-03-31 11:16 ` Michael Ellerman
2021-03-31 12:03 ` Christophe Leroy
2021-04-21 5:03 ` Jordan Niethe
2021-04-01 4:37 ` Aneesh Kumar K.V
2021-04-21 5:19 ` Jordan Niethe
2021-03-30 4:51 ` [PATCH v10 02/10] powerpc/lib/code-patching: Set up Strict RWX patching earlier Jordan Niethe
2021-03-30 4:51 ` [PATCH v10 03/10] powerpc: Always define MODULES_{VADDR,END} Jordan Niethe
2021-03-30 5:00 ` Christophe Leroy
2021-04-01 13:36 ` Christophe Leroy
2021-04-21 2:46 ` Jordan Niethe
2021-04-21 5:14 ` Christophe Leroy
2021-04-21 5:22 ` Jordan Niethe
2021-03-30 4:51 ` [PATCH v10 04/10] powerpc/kprobes: Mark newly allocated probes as ROX Jordan Niethe
2021-03-30 5:05 ` Christophe Leroy
2021-04-21 2:39 ` Jordan Niethe
2021-03-30 4:51 ` [PATCH v10 05/10] powerpc/bpf: Write protect JIT code Jordan Niethe
2021-03-31 10:37 ` Michael Ellerman
2021-03-31 10:39 ` Christophe Leroy
2021-04-21 2:35 ` Jordan Niethe
2021-04-21 6:51 ` Michael Ellerman
2021-03-30 4:51 ` [PATCH v10 06/10] powerpc/mm/ptdump: debugfs handler for W+X checks at runtime Jordan Niethe
2021-03-31 11:24 ` Michael Ellerman [this message]
2021-04-21 2:23 ` Jordan Niethe
2021-04-21 5:16 ` Christophe Leroy
2021-03-30 4:51 ` [PATCH v10 07/10] powerpc: Set ARCH_HAS_STRICT_MODULE_RWX Jordan Niethe
2021-03-30 4:51 ` [PATCH v10 08/10] powerpc/configs: Enable STRICT_MODULE_RWX in skiroot_defconfig Jordan Niethe
2021-03-30 5:27 ` Christophe Leroy
2021-04-21 2:37 ` Jordan Niethe
2021-03-30 4:51 ` [PATCH v10 09/10] powerpc/mm: implement set_memory_attr() Jordan Niethe
2021-03-30 4:51 ` [PATCH v10 10/10] powerpc/32: use set_memory_attr() Jordan Niethe
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