On 08/04/22 04:52, Yuan Yu wrote: > Currently networking can only be enabled/disabled at compile time. This > patch series will add support to disable VirtIo net at runtime even if > the functionality is built into binary at compile time. > > This will enable VMM to reduce attack surface without recompilation. > > The changes can be seen at: > https://github.com/yyu/edk2/tree/network_cfg_lib_v1 > > Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org> > Cc: Jordan Justen <jordan.l.jus...@intel.com> > Cc: Laszlo Ersek <ler...@redhat.com> > Cc: Anthony Perard <anthony.per...@citrix.com> > Cc: Julien Grall <jul...@xen.org> > > Yuan Yu (2): > OvmfPkg: Introduce NetworkCfgLib > OvmfPkg: Use PcdNetworkSupport to enable/disable VirtIo net > > OvmfPkg/OvmfPkg.dec | 3 ++ > OvmfPkg/OvmfPkgX64.dsc | 7 ++++- > OvmfPkg/Library/NetworkCfgLib/NetworkCfgLib.inf | 29 ++++++++++++++++++ > OvmfPkg/VirtioNetDxe/VirtioNet.inf | 3 ++ > OvmfPkg/Library/NetworkCfgLib/NetworkCfgLib.c | 32 ++++++++++++++++++++ > OvmfPkg/VirtioNetDxe/EntryPoint.c | 10 ++++++ > 6 files changed, 83 insertions(+), 1 deletion(-) > create mode 100644 OvmfPkg/Library/NetworkCfgLib/NetworkCfgLib.inf > create mode 100644 OvmfPkg/Library/NetworkCfgLib/NetworkCfgLib.c >
Well I've not been reviewing upstream edk2 patches for a while, but the virtio-net driver is still very close to my heart, so this patch kind of hits a nerve. I think I disagree with the idea and the implementation both. Minimally, the idea needs a much better elaboration -- what is the threat model? Do you want to protect the host from the guest, or the guest from the host? Or something else? How does controlling a single SNP driver via fw_cfg (which is also dictated by the host) help? Regarding the implementation: there is much more to networking in edk2 than VirtioNetDxe. UEFI driver binaries (SNP drivers) built from iPXE can be passed in via the NICs' option ROMs. SNP drivers can be loaded from the UEFI system partition (for example, Intel's binary-only driver for QEMU's e1000* cards). If you can control this fw_cfg switch from the VMM side, you can also control the VMM enough to simply *not give* a virtio-net device to the guest. Then the driver (it being a UEFI driver following the UEFI driver model) will simply not have anything to bind. Sorry I find this approach very wrong. If you really need it for your particular VMM, I kind of suggest not upstreaming this patch. I see it as a step backwards for the upstream project. Anyway: I emphasize I'm no longer a reviewer for OvmfPkg, and it's quite exceptional that I'm reacting at all to being CC'd on this. Laszlo -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#92102): https://edk2.groups.io/g/devel/message/92102 Mute This Topic: https://groups.io/mt/92808627/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
