Commit ae5f2fb1 authored by Committed by David S. Miller
openvswitch: Zero flows on allocation.
When support for megaflows was introduced, OVS needed to start installing flows with a mask applied to them. Since masking is an expensive operation, OVS also had an optimization that would only take the parts of the flow keys that were covered by a non-zero mask. The values stored in the remaining pieces should not matter because they are masked out. While this works fine for the purposes of matching (which must always look at the mask), serialization to netlink can be problematic. Since the flow and the mask are serialized separately, the uninitialized portions of the flow can be encoded with whatever values happen to be present. In terms of functionality, this has little effect since these fields will be masked out by definition. However, it leaks kernel memory to userspace, which is a potential security vulnerability. It is also possible that other code paths could look at the masked key and get uninitialized data, although this does not currently appear to be an issue in practice. This removes the mask optimization for flows that are being installed. This was always intended to be the case as the mask optimizations were really targetting per-packet flow operations. Fixes: 03f0d916 ("openvswitch: Mega flow implementation") Signed-off-by: Jesse Gross <email@example.com> Acked-by: Pravin B Shelar <firstname.lastname@example.org> Signed-off-by: David S. Miller <email@example.com>
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