From: Dimitri Sivanich <sivanich@hpe.com>
To: Abdifatah Suruur <suruurism@gmail.com>
Cc: linux-kernel@vger.kernel.org, Dimitri Sivanich <sivanich@hpe.com>
Subject: Re: [PATCH] char: uv_mmtimer: prevent read-only mmtimer mapping from becoming writable
Date: Thu, 20 Aug 2026 08:19:37 -0500 [thread overview]
Message-ID: <aob-6VUKRzJCYDro@hpe.com> (raw)
In-Reply-To: <20260819084224.1594-1-suruurism@gmail.com>
On Wed, Aug 19, 2026 at 11:42:24AM +0300, Abdifatah Suruur wrote:
> uv_mmtimer_mmap() rejects writable mappings of the system-wide mmtimer
> register page, but leaves VM_MAYWRITE set. Userspace can map the page
> read-only and then upgrade the mapping to writable with mprotect(),
> after which it can write to the shared RTC registers.
>
> Clear VM_MAYWRITE on the read-only path, as i915 does for its read-only
> objects and as fixed in drm/vc4 (CVE-2026-68445) and drm/panthor
> (CVE-2024-53071) and ptp: vmclock (commit
> a5edadbae57e2298a56cf7a4e774a027905a331f).
>
> Fixes: fbd8ae106850b ("char: add SGI UV mmtimer driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Abdifatah Suruur <suruurism@gmail.com>
>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
prev parent reply other threads:[~2026-08-20 14:08 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-19 8:42 Abdifatah Suruur
2026-08-20 13:19 ` Dimitri Sivanich [this message]
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