From: Nadav Amit <nadav.amit@gmail.com>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
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Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 12/13] x86/jitalloc: prepare to allocate exectuatble memory as ROX
Date: Mon, 5 Jun 2023 14:11:26 -0700 [thread overview]
Message-ID: <B021EE82-9741-4B41-8FF7-91A9336EDD7C@gmail.com> (raw)
In-Reply-To: <88a62f834688ed77d08c778e1e427014cf7d3c1b.camel@intel.com>
> On Jun 5, 2023, at 9:10 AM, Edgecombe, Rick P <rick.p.edgecombe@intel.com> wrote:
>
> On Mon, 2023-06-05 at 11:11 +0300, Mike Rapoport wrote:
>> On Sun, Jun 04, 2023 at 10:52:44PM -0400, Steven Rostedt wrote:
>>> On Thu, 1 Jun 2023 16:54:36 -0700
>>> Nadav Amit <nadav.amit@gmail.com> wrote:
>>>
>>>>> The way text_poke() is used here, it is creating a new writable
>>>>> alias
>>>>> and flushing it for *each* write to the module (like for each
>>>>> write of
>>>>> an individual relocation, etc). I was just thinking it might
>>>>> warrant
>>>>> some batching or something.
>>
>>>> I am not advocating to do so, but if you want to have many
>>>> efficient
>>>> writes, perhaps you can just disable CR0.WP. Just saying that if
>>>> you
>>>> are about to write all over the memory, text_poke() does not
>>>> provide
>>>> too much security for the poking thread.
>>
>> Heh, this is definitely and easier hack to implement :)
>
> I don't know the details, but previously there was some strong dislike
> of CR0.WP toggling. And now there is also the problem of CET. Setting
> CR0.WP=0 will #GP if CR4.CET is 1 (as it currently is for kernel IBT).
> I guess you might get away with toggling them both in some controlled
> situation, but it might be a lot easier to hack up then to be made
> fully acceptable. It does sound much more efficient though.
Thanks for highlighting this issue. I understand the limitations of
CR0.WP. There is also always the concerns that without CET or other
control flow integrity mechanism, someone would abuse (using ROP/JOP)
functions that clear CR0.WP…
next prev parent reply other threads:[~2023-06-05 21:11 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-01 10:12 [PATCH 00/13] mm: jit/text allocator Mike Rapoport
2023-06-01 10:12 ` [PATCH 01/13] nios2: define virtual address space for modules Mike Rapoport
2023-06-13 22:16 ` Dinh Nguyen
2023-06-01 10:12 ` [PATCH 02/13] mm: introduce jit_text_alloc() and use it instead of module_alloc() Mike Rapoport
2023-06-01 10:12 ` [PATCH 03/13] mm/jitalloc, arch: convert simple overrides of module_alloc to jitalloc Mike Rapoport
2023-06-01 10:12 ` [PATCH 04/13] mm/jitalloc, arch: convert remaining " Mike Rapoport
2023-06-01 22:35 ` Song Liu
2023-06-01 10:12 ` [PATCH 05/13] module, jitalloc: drop module_alloc Mike Rapoport
2023-06-01 10:12 ` [PATCH 06/13] mm/jitalloc: introduce jit_data_alloc() Mike Rapoport
2023-06-01 10:12 ` [PATCH 07/13] x86/ftrace: enable dynamic ftrace without CONFIG_MODULES Mike Rapoport
2023-06-01 10:12 ` [PATCH 08/13] arch: make jitalloc setup available regardless of CONFIG_MODULES Mike Rapoport
2023-06-01 10:12 ` [PATCH 09/13] kprobes: remove dependcy on CONFIG_MODULES Mike Rapoport
2023-06-01 10:12 ` [PATCH 10/13] modules, jitalloc: prepare to allocate executable memory as ROX Mike Rapoport
2023-06-01 10:12 ` [PATCH 11/13] ftrace: Add swap_func to ftrace_process_locs() Mike Rapoport
2023-06-01 10:12 ` [PATCH 12/13] x86/jitalloc: prepare to allocate exectuatble memory as ROX Mike Rapoport
2023-06-01 10:30 ` Peter Zijlstra
2023-06-01 11:07 ` Mike Rapoport
2023-06-02 0:02 ` Song Liu
2023-06-01 17:52 ` Kent Overstreet
2023-06-01 16:54 ` Edgecombe, Rick P
2023-06-01 18:00 ` Kent Overstreet
2023-06-01 18:13 ` Edgecombe, Rick P
2023-06-01 18:38 ` Kent Overstreet
2023-06-01 20:50 ` Edgecombe, Rick P
2023-06-01 23:54 ` Nadav Amit
2023-06-05 2:52 ` Steven Rostedt
2023-06-05 8:11 ` Mike Rapoport
2023-06-05 16:10 ` Edgecombe, Rick P
2023-06-05 20:42 ` Mike Rapoport
2023-06-05 21:01 ` Edgecombe, Rick P
2023-06-05 21:11 ` Nadav Amit [this message]
2023-06-04 21:47 ` Kent Overstreet
2023-06-01 22:49 ` Song Liu
2023-06-01 10:12 ` [PATCH 13/13] x86/jitalloc: make memory allocated for code ROX Mike Rapoport
2023-06-01 16:12 ` [PATCH 00/13] mm: jit/text allocator Mark Rutland
2023-06-01 18:14 ` Kent Overstreet
2023-06-02 9:35 ` Mark Rutland
2023-06-02 18:20 ` Song Liu
2023-06-03 21:11 ` Puranjay Mohan
2023-06-04 18:02 ` Kent Overstreet
2023-06-04 21:22 ` Song Liu
2023-06-04 21:40 ` Kent Overstreet
2023-06-05 4:05 ` Song Liu
2023-06-05 9:20 ` Mike Rapoport
2023-06-05 10:09 ` Mark Rutland
2023-06-06 10:16 ` Mike Rapoport
2023-06-06 18:21 ` Song Liu
2023-06-08 18:41 ` Mike Rapoport
2023-06-09 17:02 ` Song Liu
2023-06-12 21:34 ` Mike Rapoport
2023-06-13 18:56 ` Kent Overstreet
2023-06-13 21:09 ` Mike Rapoport
2023-07-20 8:53 ` Mike Rapoport
2023-06-05 21:13 ` Kent Overstreet
2023-06-02 0:36 ` Song Liu
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