Migrate all sandbox and VM driver network policy enforcement from
iptables to nftables. nftables provides atomic ruleset loading, a
cleaner rule syntax, and is the standard netfilter interface in modern
kernels.
Sandbox bypass enforcement (openshell-sandbox):
- Replace iptables chain of individual rule insertions with a single
atomic nftables ruleset load via nft -f
- New nft_ruleset module with pure functions for ruleset generation
and unit tests
- Combine log and reject rules in one inet family table (handles both
IPv4 and IPv6 in a single ruleset)
- Fall back to reject-only ruleset when kernel lacks nft_log support
- Enable net.netfilter.nf_log_all_netns so log rules work from
non-init network namespaces
- Use temp file for nft ruleset loading instead of stdin for
compatibility with minimal VM guest environments
VM TAP networking (openshell-driver-vm):
- Replace iptables NAT/forwarding rules with nftables equivalents
- New nft_ruleset module for TAP network rule generation with unit
tests
- Atomic table-per-TAP-device lifecycle (create/destroy)
- Host-side rules provide NAT infrastructure and defense-in-depth
isolation (input chain restricts VM to gateway port only, forward
chain blocks unsolicited inbound); primary security enforcement
happens inside the VM guest via the sandbox supervisor's own rules
VM init script:
- Load nft kernel modules at sandbox init
- Enable nf_log_all_netns sysctl for bypass detection logging
OCSF / docs:
- Update firewall rule engine references from iptables to nftables
- Document host firewall interaction model and two-layer enforcement
architecture in VM driver README and compute drivers reference
Closes#1335
Signed-off-by: Russell Bryant <rbryant@redhat.com>
* refactor!(auth): drop SSH handshake secret in favor of mTLS
The OPENSHELL_SSH_HANDSHAKE_SECRET / x-sandbox-secret mechanism was
misnamed: it does not authenticate SSH (which flows over the
RelayStream gRPC RPC and is gated by mTLS plus supervisor Unix-socket
permissions). It only gated a small set of sandbox-to-gateway
control-plane RPCs, and production deployments already enforce mTLS
on that channel — so the shared secret was redundant.
Replace the secret check with an mTLS-presence marker. Sandbox-class
methods (ReportPolicyStatus, PushSandboxLogs,
GetSandboxProviderEnvironment, SubmitPolicyAnalysis, GetSandboxConfig,
GetInferenceBundle) accept callers without a Bearer token; the gRPC
mTLS handshake is the trust boundary. Dual-auth methods treat
Bearer-present as full-scope CLI access and Bearer-absent as
sandbox-restricted scope via validate_sandbox_caller_update.
Drops the secret from all drivers (K8s, Podman, VM), the sandbox gRPC
interceptor, the Helm chart (values + pre-install hook + StatefulSet
env), the RPM bootstrap script, the man pages, and the
debug-openshell-cluster skill. Also removes the never-read
ssh_handshake_skew_secs flag and config field.
BREAKING CHANGE: --ssh-handshake-secret / OPENSHELL_SSH_HANDSHAKE_SECRET
and --ssh-handshake-skew-secs / OPENSHELL_SSH_HANDSHAKE_SKEW_SECS are
removed from the gateway, sandbox, and all driver binaries. The
openshell-ssh-handshake K8s Secret is no longer managed by the chart;
operators may delete the orphan. Deployments using
--disable-gateway-auth must enforce caller authentication at the
fronting proxy, since the gateway no longer validates a per-request
secret on sandbox-class methods.
Refs OS-174.
* docs(auth): scrub residual SSH handshake secret references
Sweep across docs, e2e scripts, the Podman driver README/NETWORKING
notes, the RPM/Helm/setup guides, the gateway man page, and RFC 0003
to remove instructions and examples that still referenced
OPENSHELL_SSH_HANDSHAKE_SECRET / --ssh-handshake-secret /
ssh_handshake_skew_secs. The mechanism is gone; nothing should still
suggest setting it. Negative-assertion regression tests are kept so
the env var cannot silently be re-introduced.
* test(drivers): drop SSH handshake secret negative-assertion tests
The supporting code, env vars, CLI flags, and config plumbing are
gone — these tests asserted absence of strings that no longer have
any path to being set. Remove the guards from the Docker, Podman,
Kubernetes, and VM driver test modules.
Russell Bryant