From: Kees Cook <keescook@chromium.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org,
Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH v3 00/30] arm64: support WXN and entry with MMU enabled
Date: Tue, 12 Apr 2022 09:59:20 -0700 [thread overview]
Message-ID: <202204120956.B0ECA2FC@keescook> (raw)
In-Reply-To: <20220411094824.4176877-1-ardb@kernel.org>
On Mon, Apr 11, 2022 at 11:47:54AM +0200, Ard Biesheuvel wrote:
> - allow WXN to be enabled (with an opt-out) so writable mappings are
> never executable;
Besides all the rest of this series's awesomeness; this really stands
out to me. I didn't even know this was a feature in aarch64. Nice! I
really like the idea of having this enabled -- anything executing out of
a writable mapping should already be considered a mistake (and tons of
work over the last 2 decades has already gone into making stuff this
doesn't happen in both the kernel and userspace). We could even make a
new LKDTM test for this. (Right now stuff like EXEC_DATA just verifies
that the .data segment doesn't have the X bit... but adding something
like EXEC_WXN where a memory region is made explicitly W+X, and it
_still_ can't be executed would be great.)
Cool!
-Kees
--
Kees Cook
prev parent reply other threads:[~2022-04-12 16:59 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-11 9:47 [PATCH v3 00/30] arm64: support WXN and entry with MMU enabled Ard Biesheuvel
2022-04-11 9:47 ` [PATCH v3 01/30] arm64: head: move kimage_vaddr variable into C file Ard Biesheuvel
2022-04-11 9:47 ` [PATCH v3 02/30] arm64: mm: make vabits_actual a build time constant if possible Ard Biesheuvel
2022-04-11 9:47 ` [PATCH v3 03/30] arm64: head: move assignment of idmap_t0sz to C code Ard Biesheuvel
2022-04-11 9:47 ` [PATCH v3 04/30] arm64: head: drop idmap_ptrs_per_pgd Ard Biesheuvel
2022-04-11 9:47 ` [PATCH v3 05/30] arm64: head: simplify page table mapping macros (slightly) Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 06/30] arm64: head: switch to map_memory macro for the extended ID map Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 07/30] arm64: head: split off idmap creation code Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 08/30] arm64: kernel: drop unnecessary PoC cache clean+invalidate Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 09/30] arm64: head: pass ID map root table address to __enable_mmu() Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 10/30] arm64: mm: provide idmap pointer to cpu_replace_ttbr1() Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 11/30] arm64: head: add helper function to remap regions in early page tables Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 12/30] arm64: head: cover entire kernel image in initial ID map Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 13/30] arm64: head: use relative references to the RELA and RELR tables Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 14/30] arm64: head: create a temporary FDT mapping in the initial ID map Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 15/30] arm64: idreg-override: use early FDT mapping in " Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 16/30] arm64: head: factor out TTBR1 assignment into a macro Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 17/30] arm64: head: populate kernel page tables with MMU and caches on Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 18/30] arm64: head: record CPU boot mode after enabling the MMU Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 19/30] arm64: kaslr: deal with init called with VA randomization enabled Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 20/30] arm64: head: relocate kernel only a single time if KASLR is enabled Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 21/30] arm64: head: remap the kernel text/inittext region read-only Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 22/30] arm64: setup: drop early FDT pointer helpers Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 23/30] arm64: mm: move ro_after_init section into the data segment Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 24/30] arm64: mm: add support for WXN memory translation attribute Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 25/30] arm64: head: record the MMU state at primary entry Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 26/30] arm64: head: avoid cache invalidation when entering with the MMU on Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 27/30] arm64: head: clean the ID map page to the PoC Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 28/30] efi: libstub: pass image handle to handle_kernel_image() Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 29/30] efi/arm64: libstub: run image in place if randomized by the loader Ard Biesheuvel
2022-04-11 9:48 ` [PATCH v3 30/30] arm64: efi/libstub: enter with the MMU on if executing in place Ard Biesheuvel
2022-04-12 16:59 ` Kees Cook [this message]
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