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[79.177.145.168]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-493eb6f373csm375363835e9.14.2026.07.11.08.52.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 11 Jul 2026 08:52:17 -0700 (PDT) Date: Sat, 11 Jul 2026 11:52:13 -0400 From: "Michael S. Tsirkin" To: Michael Bommarito Cc: Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Andrew Lunn , Jakub Kicinski , Paolo Abeni , virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] virtio_net: validate device stats reply records before use Message-ID: <20260711114248-mutt-send-email-mst@kernel.org> References: <20260711150754.2918392-1-michael.bommarito@gmail.com> <20260711111503-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Sat, Jul 11, 2026 at 11:29:56AM -0400, Michael Bommarito wrote: > On Sat, Jul 11, 2026 at 11:20 AM Michael S. Tsirkin wrote: > > Why does it "matter most", or at all, there? > > Host can always deny guest service. In fact, this is how cloud vendors > > charge their clients, by denying service to whoever did not pay them. > ... > > I'm all for making things easier to debug even when the device is buggy. > > But I'm not inclined to add tons of hard to maintain code to > > that end, and I would be worried broken hosts will come to > > rely on drivers working around them. > > I am always confused by the CoCo threat model to be honest, Confidential computing? It's vague at points, given the term covers a lot of different hardware. But one thing is clear - it's about confidentiality. DoS by host is empathically outside the threat model. On any virtualization platform I know without exception, host can just exit the VM, done, service denied. > since it > seems like some people care a lot about maximalist reliance on the > contract and other people are more practical about how many other > vectors exist anyway. I don't really know what "vectors" or "the contract" are here. Making a guest recover from a misbehaving device has as much a chance to reduce security as increase it. So the only benefit is robustness for users/developers, not security. And that has to be weighted against the maintainance cost of the change. This one is too costly, I judge. > No hard feelings if you want to NACK, but at > least it's documented publicly now for people to consider. > > Thanks, > Mike