From: Breno Leitao <leitao@debian.org>
To: sashiko-reviews@lists.linux.dev
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Michal Hocko <mhocko@suse.com>,
Naoya Horiguchi <nao.horiguchi@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
kas@kernel.org, Vlastimil Babka <vbabka@kernel.org>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
David Hildenbrand <david@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
Brendan Jackman <brendan.jackman@linux.dev>,
Johannes Weiner <hannes@cmpxchg.org>,
Borislav Petkov <bp@alien8.de>,
Suren Baghdasaryan <surenb@google.com>,
Ard Biesheuvel <ardb@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Miaohe Lin <linmiaohe@huawei.com>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Zi Yan <ziy@nvidia.com>, Thomas Gleixner <tglx@kernel.org>,
kernel-team@meta.com, rmikey@meta.com, harry@kernel.org,
linux-efi@vger.kernel.org, riel@surriel.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kexec@lists.infradead.org
Subject: Re: [PATCH v4 3/5] mm/memory-failure: efi: record hardware-poisoned frames into the poisoned-memory table
Date: Wed, 9 Sep 2026 07:05:57 -0700 [thread overview]
Message-ID: <aqFm1ep0mIlJpA-d@gmail.com> (raw)
In-Reply-To: <20260909132128.AD4D01F00A3A@smtp.kernel.org>
On Wed, Sep 09, 2026 at 01:21:28PM +0000, sashiko-bot@kernel.org wrote:
> > --- /dev/null
> > +++ b/drivers/firmware/efi/poison.c
> >
> > + /* Whole words, and a bit count that can be taken without wrapping. */
> > + if (!pm->size || !IS_ALIGNED(pm->size, sizeof(unsigned long)) ||
> > + check_mul_overflow(pm->size, (u64)BITS_PER_BYTE, &nbits))
> > + return false;
>
> [Severity: High]
> Does this validation fully protect against an excessively large pm->size?
I was clamping the table before, but we decided to drop it in the last
revision. See the discusion in here:
https://lore.kernel.org/all/apGWUWi5-RbhFHpe@thinkstation/
> > + start = PAGE_ALIGN_DOWN(efi.poisoned_memory);
> > + end = PAGE_ALIGN(efi.poisoned_memory + sizeof(*pm) + pm->size);
>
> [Severity: High]
> Can this computation wrap around if pm->size is maliciously large?
Yes, but that means that someone was able to write to EFI memory to
update size?
I can definitely BUG_ON() on "large" pm->size, but, I don't think this
is what we want here.
next prev parent reply other threads:[~2026-09-09 14:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-09 13:05 [PATCH v4 0/5] mm/memory-failure: keep hardware-poisoned pages out of the next kexec Breno Leitao
2026-09-09 13:05 ` [PATCH v4 1/5] mm/memory-failure: efi: add the LINUX_EFI_POISONED_MEMORY configuration table Breno Leitao
2026-09-09 13:13 ` sashiko-bot
2026-09-09 13:05 ` [PATCH v4 2/5] mm/memory-failure: libstub: install the poisoned-memory EFI table Breno Leitao
2026-09-09 13:19 ` sashiko-bot
2026-09-09 14:00 ` Breno Leitao
2026-09-09 14:47 ` Ard Biesheuvel
2026-09-10 13:11 ` Breno Leitao
2026-09-09 13:05 ` [PATCH v4 3/5] mm/memory-failure: efi: record hardware-poisoned frames into the poisoned-memory table Breno Leitao
2026-09-09 13:21 ` sashiko-bot
2026-09-09 14:05 ` Breno Leitao [this message]
2026-09-09 13:05 ` [PATCH v4 4/5] mm/memory-failure: efi: answer whether a range is poisoned Breno Leitao
2026-09-09 13:17 ` sashiko-bot
2026-09-09 13:05 ` [PATCH v4 5/5] mm/memory-failure: keep inherited poisoned frames out of the buddy allocator Breno Leitao
2026-09-09 13:24 ` sashiko-bot
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