mantle/qemu: neuter virtiofsd seccomp filtering #3636
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By default, `virtiofsd` uses seccomp to allow only some syscalls to be proxied from the guest. In the theme of `--sandbox=none`, let's also neuter seccomp filtering for our virtiofs usage; the workloads we run in the supermin/dev VMs are trusted. Incidentally, this avoids issues like coreos#3635, where some syscalls were accidentally missing from the allow list. In this case, new libostree code[[1]] running in the supermin VM when building the legacy oscontainer calls out to `fstatfs` over virtiofs, which maps to the blocked `fstatfs64` syscall on ppc64le. (I've opened an upstream patch[[2]] to fix this, but we don't strictly need it.) Closes: coreos#3635 [1]: ostreedev/ostree@ba9c9de [2]: https://gitlab.com/virtio-fs/virtiofsd/-/merge_requests/200
cgwalters
approved these changes
Sep 26, 2023
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By default,
virtiofsduses seccomp to allow only some syscalls to be proxied from the guest. In the theme of--sandbox=none, let's also neuter seccomp filtering for our virtiofs usage; the workloads we run in the supermin/dev VMs are trusted.Incidentally, this avoids issues like #3635, where some syscalls were accidentally missing from the allow list. In this case, new libostree code[1] running in the supermin VM when building the legacy oscontainer calls out to
fstatfsover virtiofs, which maps to the blockedfstatfs64syscall on ppc64le. (I've opened an upstream patch[2] to fix this, but we don't strictly need it.)Closes: #3635