From: Sean Christopherson <seanjc@google.com>
To: redacherkaoui <redacherkaoui67@gmail.com>
Cc: pbonzini@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org,
redahack12-glitch <redahack12@gmail.com>
Subject: Re: [PATCH] KVM: coalesced_mmio: Fix out-of-bounds write in coalesced_mmio_write()
Date: Mon, 1 Dec 2025 11:03:17 -0800 [thread overview]
Message-ID: <aS3mdTKmTFIpc3ye@google.com> (raw)
In-Reply-To: <20251127001132.13704-1-redacherkaoui67@gmail.com>
On Thu, Nov 27, 2025, redacherkaoui wrote:
> From: redahack12-glitch <redahack12@gmail.com>
>
> The coalesced MMIO ring stores each entry's MMIO payload in an 8-byte
> fixed-size buffer (data[8]). However, coalesced_mmio_write() copies
> the payload using memcpy(..., len) without verifying that 'len' does not
> exceed the buffer size.
>
> A malicious
KVM controls all callers.
> or buggy caller could therefore trigger a write past the end of the data[]
> array and corrupt adjacent kernel memory inside the ring page.
True, but if a caller is buggy, KVM likely has bigger problems because KVM relies
on MMIO (and PIO) accesses being no larger than 8 in a number of locations. If
we want to harden KVM, kvm_iodevice_{read,write}() would be a better place for a
sanity check.
prev parent reply other threads:[~2025-12-01 19:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-27 0:11 [PATCH] KVM: coalesced_mmio: Fix out-of-bounds write in coalesced_mmio_write() redacherkaoui
2025-12-01 19:03 ` Sean Christopherson [this message]
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