linux-kernel - Re: [PATCH 1/2] arm64/pageattr: Propagate return value from __change_memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aR4GhuhEISNSSbUf@arm.com>
Date: Wed, 19 Nov 2025 18:03:50 +0000
From: Catalin Marinas <catalin.marinas@....com>
To: Dev Jain <dev.jain@....com>
Cc: will@...nel.org, ryan.roberts@....com, rppt@...nel.org,
	shijie@...amperecomputing.com, yang@...amperecomputing.com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] arm64/pageattr: Propagate return value from
 __change_memory_common

On Wed, Nov 12, 2025 at 11:57:15AM +0530, Dev Jain wrote:
> The rodata=on security measure requires that any code path which does
> vmalloc -> set_memory_ro/set_memory_rox must protect the linear map alias
> too. Therefore, if such a call fails, we must abort set_memory_* and caller
> must take appropriate action; currently we are suppressing the error, and
> there is a real chance of such an error arising post commit a166563e7ec3
> ("arm64: mm: support large block mapping when rodata=full"). Therefore,
> propagate any error to the caller.
> 
> Fixes: a166563e7ec3 ("arm64: mm: support large block mapping when rodata=full")
> Signed-off-by: Dev Jain <dev.jain@....com>
> ---
> v1 of this patch: https://lore.kernel.org/all/20251103061306.82034-1-dev.jain@arm.com/
> I have dropped stable since no real chance of failure was there.

I couldn't figure out from the comments on v1 whether Will's concern was
addressed:

https://lore.kernel.org/all/aQn4EwKar66UZ7rz@willie-the-truck/

IOW, is the patch necessary? What are the failure scenarios and what
does the caller do? It's good to propagate an error to the caller but
patch also changes the current behaviour by bailing out earlier.

-- 
Catalin