Re: [Qemu-devel] [PATCH] Add ability to provide ifname when using netdev bridge or tap helper

[Paolo Bonzini <pbonzini@redhat.com>]

On 17/01/2018 11:31, Daniel P. Berrange wrote:
> 
> eg consider the user asks for a tap device called  eth1. To the
> sysadmin the user's tap device now looks like a physical NIC.
> This can be even worse if the host does physical NIC hotplug,
> or uses SRIOV. eg consider the host as eth0 -> eth7 for SRIOV
> NICs, and eth3 is given to a guest. Now a user uses the setuid
> helper to ask for a TAP called eth3. When the SRIOV device is
> later released by the guest it will end up called eth8, as the
> TAP device occupies eth3. In bad cases this could even cause
> the host mgmt layer to configure bogus addresses on the eth3
> TAP device instead of the SRIOV device.
> 
> If we want to allow ifname to be set via the setuid helper, then IMHO,
> the config file for the helper *must* whitelist the various permitted
> naming patterns.

Indeed, a similar patch has been proposed several times, and always the
response was the same as Daniel's. :)

Paolo