chore(vm): refresh runtime defaults and hardening

Signed-off-by: Drew Newberry <anewberry@nvidia.com>

crates/openshell-driver-vm/README.md

@@ -47,6 +47,7 @@ First run takes a few minutes while `mise run vm:setup` stages libkrun/libkrunfw
 By default `mise run gateway:vm`:
 
 - Listens on plaintext HTTP at `127.0.0.1:18081`.
+- Uses `nvcr.io/nvidia/base/ubuntu:24.04` as the sandbox and bootstrap image.
 - Configures the gateway installation name as `vm-dev` and registers the same
   name with the CLI by writing
   `~/.config/openshell/gateways/vm-dev/metadata.json`. It does not modify the

crates/openshell-driver-vm/runtime/kernel/openshell.kconfig

@@ -35,3 +35,11 @@ CONFIG_SECURITY_LANDLOCK=y
 CONFIG_LSM="landlock,lockdown,yama,loadpin,safesetid,ipe,bpf"
 CONFIG_SECCOMP=y
 CONFIG_SECCOMP_FILTER=y
+
+# Kernel memory hardening. Keep init-on-free disabled because its runtime cost
+# is too high for sandbox workloads.
+CONFIG_HARDENED_USERCOPY=y
+CONFIG_INIT_STACK_ALL_ZERO=y
+CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
+# CONFIG_INIT_ON_FREE_DEFAULT_ON is not set
+CONFIG_SLAB_FREELIST_RANDOM=y

crates/openshell-driver-vm/runtime/pins.env

@@ -4,8 +4,7 @@
 # Pinned dependency versions for the openshell-driver-vm runtime.
 #
 # This file is sourced by VM runtime packaging scripts. It centralises version
-# pins and content-addressed digests so that builds are reproducible and
-# auditable.
+# pins so that builds are reproducible and auditable.
 #
 # Environment variables override these defaults — CI and local dev workflows
 # can still set the runtime dependency versions below.
@@ -15,30 +14,20 @@
 #   2. Run the relevant build script to verify.
 #   3. Commit pins.env alongside any script changes.
 
-# ── Base Docker image (digest-pinned) ──────────────────────────────────
-# Tag: nvcr.io/nvidia/base/ubuntu:noble-20251013
-VM_BASE_IMAGE="${VM_BASE_IMAGE:-nvcr.io/nvidia/base/ubuntu@sha256:43fa5063e80fbbc533892af3ccca190868ce48db5a8928b19d7815c40436af8e}"
-
-# ── Container images for rootfs pre-loading (digest-pinned) ────────────
-# Tag: registry.k8s.io/agent-sandbox/agent-sandbox-controller:v0.1.0
-AGENT_SANDBOX_IMAGE="${AGENT_SANDBOX_IMAGE:-registry.k8s.io/agent-sandbox/agent-sandbox-controller@sha256:ba71ea40ae0872791197badf2ab84f3f482df3902f1fce7ca9e076b1de9b57f6}"
-# Tag: ghcr.io/nvidia/openshell-community/sandboxes/base:latest
-COMMUNITY_SANDBOX_IMAGE="${COMMUNITY_SANDBOX_IMAGE:-ghcr.io/nvidia/openshell-community/sandboxes/base@sha256:d446c17105e7448e602238a8a5a4ddd0233c071082406522f81c31f8b1309525}"
-
 # SERVER_IMAGE is intentionally NOT pinned here — it changes frequently
 # during local development. Override via IMAGE_REPO_BASE and IMAGE_TAG
 # environment variables (defaults: openshell/gateway:dev).
 
-# ── umoci (guest OCI unpacker) ──────────────────────────────────────────
+# ── umoci (guest OCI unpacker) ───────────────────────────────────────
 # Repo: https://github.com/opencontainers/umoci
 UMOCI_VERSION="${UMOCI_VERSION:-v0.6.0}"
 
-# ── libkrunfw upstream (commit-pinned) ─────────────────────────────────
+# ── libkrunfw upstream (commit-pinned) ────────────────────────────────
 # Repo: https://github.com/libkrun/libkrunfw
-# Pinned: v5.6.1 (2026-09-16)
+# Pinned: v5.6.1 (Linux 6.12.109, 2026-09-16)
 LIBKRUNFW_REF="${LIBKRUNFW_REF:-617938cf2ae9a3a0e5696d23a5d6252cd7a1ef4f}"
 
-# ── libkrun upstream (commit-pinned) ──────────────────────────────────
+# ── libkrun upstream (commit-pinned) ─────────────────────────────────
 # Repo: https://github.com/libkrun/libkrun
 # Pinned: v1.19.4 (2026-09-16)
 LIBKRUN_REF="${LIBKRUN_REF:-728df8125077d0db44265f6e997c72b81b65c015}"

crates/openshell-gateway/src/vm.rs

@@ -58,6 +58,7 @@ use tower::service_fn;
 const DRIVER_BIN_NAME: &str = "openshell-driver-vm";
 const COMPUTE_DRIVER_SOCKET_RUN_DIR: &str = "run";
 const COMPUTE_DRIVER_SOCKET_NAME: &str = "compute-driver.sock";
+const DEFAULT_VM_SANDBOX_IMAGE: &str = "nvcr.io/nvidia/base/ubuntu:24.04";
 
 /// Configuration for launching and talking to the VM compute driver.
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
@@ -233,7 +234,7 @@ impl Default for VmComputeConfig {
         Self {
             state_dir: Self::default_state_dir(),
             driver_dir: None,
-            default_image: openshell_core::image::default_sandbox_image(),
+            default_image: DEFAULT_VM_SANDBOX_IMAGE.to_string(),
             grpc_endpoint: String::new(),
             bootstrap_image: String::new(),
             krun_log_level: Self::default_krun_log_level(),
@@ -759,7 +760,7 @@ async fn connect_compute_driver(socket_path: &Path) -> Result<Channel> {
 #[cfg(all(test, unix))]
 mod tests {
     use super::{
-        VmComputeConfig, append_otlp_args, append_vm_identity_args,
+        DEFAULT_VM_SANDBOX_IMAGE, VmComputeConfig, append_otlp_args, append_vm_identity_args,
         append_vm_proxy_and_spiffe_args, append_vm_rootfs_tar_args, compute_driver_guest_tls_paths,
         compute_driver_socket_path, current_euid, prepare_compute_driver_socket_path,
         prepare_vm_state_dir, resolve_compute_driver_bin, resolve_driver_search_dirs,
@@ -772,6 +773,14 @@ mod tests {
     use std::path::PathBuf;
     use tempfile::tempdir;
 
+    #[test]
+    fn vm_uses_nvidia_ubuntu_default_image() {
+        assert_eq!(
+            VmComputeConfig::default().default_image,
+            DEFAULT_VM_SANDBOX_IMAGE
+        );
+    }
+
     #[test]
     fn vm_driver_command_includes_gateway_otlp_configuration() {
         let mut command = tokio::process::Command::new("openshell-driver-vm");

docs/reference/gateway-config.mdx

@@ -911,12 +911,12 @@ guest_tls_key  = "/var/lib/openshell/guest-tls/client-key.pem"
 state_dir        = "/var/lib/openshell/vm"
 # Where the gateway looks for the openshell-driver-vm subprocess binary.
 driver_dir       = "/usr/local/libexec/openshell"
-default_image    = "ghcr.io/nvidia/openshell-community/sandboxes/base:latest"
+default_image    = "nvcr.io/nvidia/base/ubuntu:24.04"
 # Optional override. When omitted, the gateway derives
 # https://host.openshell.internal:<gateway-port> for the VM driver.
 grpc_endpoint    = "https://host.openshell.internal:17670"
 # Empty falls back to default_image.
-bootstrap_image  = "ghcr.io/nvidia/openshell-community/sandboxes/base:latest"
+bootstrap_image  = "nvcr.io/nvidia/base/ubuntu:24.04"
 krun_log_level   = 1
 vcpus            = 2
 mem_mib          = 2048

docs/reference/sandbox-compute-drivers.mdx

@@ -363,7 +363,7 @@ compute_driver = "vm"
 
 For a launch-time override, set `OPENSHELL_COMPUTE_DRIVER=vm` in the gateway environment and restart the service.
 
-Configure VM driver values such as `grpc_endpoint`, `driver_dir`, `state_dir`, `default_image`, `bootstrap_image`, `vcpus`, `mem_mib`, `overlay_disk_mib`, `krun_log_level`, and `guest_tls_*` in `[openshell.drivers.vm]`. The VM `state_dir` stores overlay disks, console logs, runtime state, image-rootfs cache, and the private `run/compute-driver.sock` socket. The VM socket path is managed by the gateway and is not configurable through remote endpoint settings.
+Configure VM driver values such as `grpc_endpoint`, `driver_dir`, `state_dir`, `default_image`, `bootstrap_image`, `vcpus`, `mem_mib`, `overlay_disk_mib`, `krun_log_level`, and `guest_tls_*` in `[openshell.drivers.vm]`. The default sandbox image is `nvcr.io/nvidia/base/ubuntu:24.04`. The VM `state_dir` stores overlay disks, console logs, runtime state, image-rootfs cache, and the private `run/compute-driver.sock` socket. The VM socket path is managed by the gateway and is not configurable through remote endpoint settings.
 
 The gateway starts `openshell-driver-vm` over a private Unix socket and passes its process ID so the driver can reject unexpected local clients. The driver's standalone TCP listener is disabled unless `--allow-unauthenticated-tcp` is set for local development.
 

e2e/rust/e2e-vm.sh

@@ -51,7 +51,7 @@ DRIVER_BIN="${OPENSHELL_VM_DRIVER_BIN:-${ROOT}/target/debug/openshell-driver-vm}
 CLI_BIN="${OPENSHELL_BIN:-${ROOT}/target/debug/openshell}"
 E2E_TEST_OVERRIDE="${OPENSHELL_E2E_VM_TEST:-}"
 E2E_FEATURES="${OPENSHELL_E2E_VM_FEATURES-e2e-vm}"
-SANDBOX_IMAGE="${OPENSHELL_SANDBOX_IMAGE:-${COMMUNITY_SANDBOX_IMAGE:-ghcr.io/nvidia/openshell-community/sandboxes/base:latest}}"
+SANDBOX_IMAGE="${OPENSHELL_SANDBOX_IMAGE:-nvcr.io/nvidia/base/ubuntu:24.04}"
 
 # The VM driver places `compute-driver.sock` under `[openshell.drivers.vm].state_dir`.
 # AF_UNIX SUN_LEN is 104 bytes on macOS (108 on Linux), so paths anchored

tasks/scripts/gateway-vm.sh

@@ -39,7 +39,7 @@ PORT="${OPENSHELL_SERVER_PORT:-18081}"
 GATEWAY_NAME="${OPENSHELL_VM_GATEWAY_NAME:-vm-dev}"
 STATE_DIR="${OPENSHELL_VM_GATEWAY_STATE_DIR:-${ROOT}/.cache/gateway-vm}"
 SANDBOX_NAMESPACE="${OPENSHELL_SANDBOX_NAMESPACE:-vm-dev}"
-SANDBOX_IMAGE="${OPENSHELL_SANDBOX_IMAGE:-${COMMUNITY_SANDBOX_IMAGE:-ghcr.io/nvidia/openshell-community/sandboxes/base:latest}}"
+SANDBOX_IMAGE="${OPENSHELL_SANDBOX_IMAGE:-nvcr.io/nvidia/base/ubuntu:24.04}"
 VM_BOOTSTRAP_IMAGE="${OPENSHELL_VM_BOOTSTRAP_IMAGE:-}"
 SANDBOX_IMAGE_PULL_POLICY="${OPENSHELL_SANDBOX_IMAGE_PULL_POLICY:-if_not_present}"
 # VM currently has no image-pull-policy setting in its driver configuration; unlike

tasks/scripts/vm/build-libkrun.sh

@@ -216,15 +216,25 @@ if [ -f openshell.kconfig ]; then
     CONFIG_SECURITY \
     CONFIG_SECURITY_LANDLOCK \
     CONFIG_SECCOMP \
-    CONFIG_SECCOMP_FILTER; do
-    val="$(grep "^${opt}=" "${KERNEL_SOURCES}/.config" 2>/dev/null || true)"
-    if [ -n "$val" ]; then
-      echo "    ${opt}: ${val#*=}"
+    CONFIG_SECCOMP_FILTER \
+    CONFIG_HARDENED_USERCOPY \
+    CONFIG_INIT_STACK_ALL_ZERO \
+    CONFIG_INIT_ON_ALLOC_DEFAULT_ON \
+    CONFIG_SLAB_FREELIST_RANDOM; do
+    val="$(grep -E "^(# )?${opt}(=| )" "${KERNEL_SOURCES}/.config" 2>/dev/null || true)"
+    if [ "$val" = "${opt}=y" ]; then
+      echo "    ${opt}: y"
     else
-      echo "    WARNING: ${opt} not set after merge!" >&2
+      echo "    WARNING: ${opt} is not enabled after merge: ${val:-unset}" >&2
       all_ok=false
     fi
   done
+  if grep -qx '# CONFIG_INIT_ON_FREE_DEFAULT_ON is not set' "${KERNEL_SOURCES}/.config"; then
+    echo "    CONFIG_INIT_ON_FREE_DEFAULT_ON: disabled"
+  else
+    echo "    WARNING: CONFIG_INIT_ON_FREE_DEFAULT_ON is not explicitly disabled after merge!" >&2
+    all_ok=false
+  fi
   lsm_order="$(grep '^CONFIG_LSM=' "${KERNEL_SOURCES}/.config" 2>/dev/null || true)"
   if [[ "$lsm_order" == *landlock* ]]; then
     echo "    CONFIG_LSM: ${lsm_order#*=}"