Bind production cold start to installed Lazaret authorities

crates/lazaret-host-coordinator/Cargo.toml

@@ -19,6 +19,7 @@ ed25519-dalek.workspace = true
 getrandom.workspace = true
 lazaret-core = { version = "=0.0.0", path = "../lazaret-core" }
 lazaret-linux = { version = "=0.0.0", path = "../lazaret-linux" }
+lazaret-prepared-lower = { version = "=0.0.0", path = "../lazaret-prepared-lower" }
 lazaret-runtime-supervisor = { version = "=0.0.0", path = "../lazaret-runtime-supervisor" }
 lazaret-state-anchor = { version = "=0.0.0", path = "../lazaret-state-anchor" }
 lazaret-storage-catalog = { version = "=0.0.0", path = "../lazaret-storage-catalog" }

crates/lazaret-host-coordinator/src/lib.rs

@@ -7,5 +7,7 @@ pub mod escalation;
 pub mod lifecycle;
 pub mod network;
 pub mod production;
+pub mod production_selector;
 pub mod runtime;
+pub mod sandbox_init;
 pub mod state_anchor;

crates/lazaret-host-coordinator/src/main.rs

@@ -1,5 +1,8 @@
 fn main() {
     let arguments = std::env::args_os().skip(1).collect::<Vec<_>>();
+    if lazaret_host_coordinator::sandbox_init::dispatch_private_sandbox_init(&arguments) {
+        return;
+    }
     if let Some(result) = lazaret_linux::process::dispatch_private_process_role(&arguments) {
         if let Err(error) = result {
             eprintln!("private process role failed: {error}");

crates/lazaret-host-coordinator/src/production.rs

@@ -66,6 +66,7 @@ pub struct ProductionColdStartInputs<'a> {
     pub container_id: ContainerId,
     pub invoking_uid: u32,
     pub escalation_client: &'a File,
+    pub sandbox_init: &'a File,
 }
 
 pub struct BootstrapOwnerGuard {
@@ -138,6 +139,7 @@ impl<'a> ProductionColdStart<'a> {
             inputs.configuration.runtime_domain_root(),
             inputs.container_id,
             inputs.escalation_client,
+            inputs.sandbox_init,
             inputs.invoking_uid,
         )
         .map_err(|error| failure(format!("runtime staging: {error}")))?;
@@ -293,6 +295,7 @@ impl RuntimeStaging {
         runtime_domain: &ConfinedPathPlan,
         container_id: ContainerId,
         escalation_client: &File,
+        sandbox_init: &File,
         invoking_uid: u32,
     ) -> Result<Self, ProductionColdStartError> {
         let root = runtime_domain.open_authority().map_err(failure)?;
@@ -325,11 +328,15 @@ impl RuntimeStaging {
             bundle_identity,
             control_identity,
         };
-        staging.populate_control(escalation_client)?;
+        staging.populate_control(escalation_client, sandbox_init)?;
         Ok(staging)
     }
 
-    fn populate_control(&self, escalation_client: &File) -> Result<(), ProductionColdStartError> {
+    fn populate_control(
+        &self,
+        escalation_client: &File,
+        sandbox_init: &File,
+    ) -> Result<(), ProductionColdStartError> {
         let invoking_uid = fstat(&self.control).map_err(failure)?.st_uid;
         drop(open_or_create_private_directory(
             &self.control,
@@ -352,15 +359,10 @@ impl RuntimeStaging {
             true,
         )?);
         let bin = open_or_create_private_directory(&self.control, "bin", invoking_uid, true)?;
-        let source = escalation_client
-            .metadata()
-            .map_err(|error| failure(format!("inspecting escalation client: {error}")))?;
-        if !source.file_type().is_file() || source.permissions().mode() & 0o111 == 0 {
-            return Err(ProductionColdStartError(
-                "escalation client is not an executable regular file".into(),
-            ));
-        }
+        require_executable_regular_file(escalation_client, "escalation client")?;
         copy_descriptor(escalation_client, &bin, "lazaret-escalate", invoking_uid)?;
+        require_executable_regular_file(sandbox_init, "sandbox init")?;
+        copy_descriptor(sandbox_init, &bin, "lazaret-sandbox-init", invoking_uid)?;
         Ok(())
     }
 
@@ -414,6 +416,21 @@ fn copy_descriptor(
     require_private_file(&destination, invoking_uid, 0o700)
 }
 
+fn require_executable_regular_file(
+    source: &File,
+    label: &str,
+) -> Result<(), ProductionColdStartError> {
+    let metadata = source
+        .metadata()
+        .map_err(|error| failure(format!("inspecting {label}: {error}")))?;
+    if !metadata.file_type().is_file() || metadata.permissions().mode() & 0o111 == 0 {
+        return Err(ProductionColdStartError(format!(
+            "{label} is not an executable regular file"
+        )));
+    }
+    Ok(())
+}
+
 #[derive(Clone, Copy)]
 struct FileIdentity {
     device: u64,

crates/lazaret-host-coordinator/src/production_selector.rs

@@ -0,0 +1,405 @@
+use std::collections::BTreeSet;
+use std::fmt;
+use std::fs::File;
+use std::os::unix::fs::PermissionsExt;
+use std::path::Path;
+use std::sync::Arc;
+
+use lazaret_core::configuration::ResolvedDomainConfiguration;
+use lazaret_core::identity::{
+    ConfigurationFingerprint, ContainerId, CoordinatorId, DomainId, GenerationId, NetworkSidecarId,
+    PrepareOperationId, SandboxId,
+};
+use lazaret_core::network::{DnsQueryExpectation, ReachabilityExpectation};
+use lazaret_core::records::{DurableDecision, Generation, IpAddress, PreparedArtifact};
+use lazaret_linux::filesystem::namespace_identity;
+use lazaret_prepared_lower::{
+    IdMap, IdMapRange, OciRegistryTransport, Platform, PreparedLowerStore, RegistryCredentials,
+};
+use lazaret_runtime_supervisor::network::{DnsProbeTarget, NetworkProbeRequest, TcpProbeTarget};
+use lazaret_runtime_supervisor::sandbox::{RootProcess, SANDBOX_INIT_DESTINATION};
+use lazaret_storage_catalog::{Catalog, CatalogError};
+use rustix::fs::{Mode, OFlags, ResolveFlags, openat2};
+
+use crate::domain_store::HostCoordinatorDomainStore;
+use crate::production::ProductionColdStartInputs;
+use crate::sandbox_init::PRIVATE_SANDBOX_INIT_ROLE;
+
+const NETWORK_NAMESPACE_PATH: &str = "/proc/self/ns/net";
+
+#[derive(Debug)]
+pub struct ProductionSelectionError(String);
+
+impl fmt::Display for ProductionSelectionError {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        formatter.write_str(&self.0)
+    }
+}
+
+impl std::error::Error for ProductionSelectionError {}
+
+fn failure(error: impl fmt::Display) -> ProductionSelectionError {
+    ProductionSelectionError(error.to_string())
+}
+
+pub struct InstalledProductPaths<'a> {
+    pub escalation_client: &'a Path,
+    pub sandbox_init: &'a Path,
+}
+
+pub struct ProductionSelection {
+    domain_id: DomainId,
+    configuration_fingerprint: ConfigurationFingerprint,
+    catalog: Catalog,
+    artifact: PreparedArtifact,
+    generation: Generation,
+    resolver_addresses: Vec<IpAddress>,
+    network_probe: NetworkProbeRequest,
+    reachability: ReachabilityExpectation,
+    container_id: ContainerId,
+    escalation_client: File,
+    sandbox_init: File,
+}
+
+impl ProductionSelection {
+    /// Borrows the selected resources as the existing production cold-start input.
+    ///
+    /// # Errors
+    /// Refuses a configuration other than the exact one used for selection.
+    pub fn cold_start_inputs<'a>(
+        &'a self,
+        store: Arc<HostCoordinatorDomainStore>,
+        configuration: &'a ResolvedDomainConfiguration,
+    ) -> Result<ProductionColdStartInputs<'a>, ProductionSelectionError> {
+        if configuration.domain_id() != self.domain_id
+            || configuration.configuration_fingerprint() != self.configuration_fingerprint
+        {
+            return Err(failure("selected cold start does not match configuration"));
+        }
+        Ok(ProductionColdStartInputs {
+            store,
+            catalog: &self.catalog,
+            configuration,
+            generation: self.generation.clone(),
+            prepared_artifact: &self.artifact,
+            root_process: RootProcess::new(
+                SANDBOX_INIT_DESTINATION,
+                [PRIVATE_SANDBOX_INIT_ROLE.to_owned()],
+            )
+            .map_err(failure)?,
+            resolver_addresses: self.resolver_addresses.clone(),
+            network_probe: self.network_probe.clone(),
+            reachability: self.reachability.clone(),
+            container_id: self.container_id,
+            invoking_uid: rustix::process::getuid().as_raw(),
+            escalation_client: &self.escalation_client,
+            sandbox_init: &self.sandbox_init,
+        })
+    }
+}
+
+/// Selects and prepares every Host Coordinator-owned cold-start input.
+///
+/// # Errors
+/// Refuses invalid installed paths, unsupported architectures, registry or image failures,
+/// changed Storage Root authority, exhausted identities, and configuration-policy mismatch.
+pub async fn select_production_cold_start(
+    configuration: &ResolvedDomainConfiguration,
+    store: &HostCoordinatorDomainStore,
+    product_paths: InstalledProductPaths<'_>,
+) -> Result<ProductionSelection, ProductionSelectionError> {
+    let escalation_client = open_installed_executable(product_paths.escalation_client)?;
+    let sandbox_init = open_installed_executable(product_paths.sandbox_init)?;
+    let catalog = Catalog::under_storage_root(configuration.storage_root()).map_err(failure)?;
+    match catalog.initialize() {
+        Ok(()) | Err(CatalogError::AlreadyInitialized) => {}
+        Err(error) => return Err(failure(error)),
+    }
+    let prepared =
+        PreparedLowerStore::under_storage_root(configuration.storage_root(), catalog.clone())
+            .map_err(failure)?;
+    let image = OciRegistryTransport
+        .pull_confined(
+            &configuration.fingerprint_record().image,
+            &RegistryCredentials::Anonymous,
+            &host_platform()?,
+            configuration.storage_root(),
+            random_id()?,
+        )
+        .await
+        .map_err(|error| failure(format!("pulling configured anonymous OCI image: {error}")))?;
+    let artifact = prepared
+        .prepare_transported(
+            PrepareOperationId::new(random_id()?),
+            &image,
+            rootless_id_map(),
+        )
+        .map_err(failure)?;
+    image.cleanup().map_err(failure)?;
+
+    let next_generation = store
+        .snapshot()
+        .map_err(failure)?
+        .generations
+        .iter()
+        .map(|generation| generation.generation_id.get())
+        .max()
+        .unwrap_or(0)
+        .checked_add(1)
+        .ok_or_else(|| failure("generation identity exhausted"))?;
+    let (coordinator_id, network_sidecar_id, sandbox_id) = distinct_generation_ids()?;
+    let generation = Generation {
+        domain_id: configuration.domain_id(),
+        generation_id: GenerationId::new(next_generation),
+        configuration_fingerprint: configuration.configuration_fingerprint(),
+        coordinator_id,
+        network_sidecar_id,
+        sandbox_id,
+        durable_decision: DurableDecision::None,
+    };
+    let namespace = namespace_identity(Path::new(NETWORK_NAMESPACE_PATH)).map_err(failure)?;
+    let (resolver_addresses, network_probe, reachability) =
+        select_network_readiness(configuration, &generation, namespace);
+    Ok(ProductionSelection {
+        domain_id: configuration.domain_id(),
+        configuration_fingerprint: configuration.configuration_fingerprint(),
+        catalog,
+        artifact,
+        generation,
+        resolver_addresses,
+        network_probe,
+        reachability,
+        container_id: ContainerId::new(random_id()?),
+        escalation_client,
+        sandbox_init,
+    })
+}
+
+fn select_network_readiness(
+    configuration: &ResolvedDomainConfiguration,
+    generation: &Generation,
+    enforcement_namespace: lazaret_core::identity::NamespaceIdentity,
+) -> (Vec<IpAddress>, NetworkProbeRequest, ReachabilityExpectation) {
+    let readiness = configuration.network_readiness();
+    let denied = readiness
+        .denied
+        .iter()
+        .map(|target| TcpProbeTarget {
+            address: IpAddress::V4(target.address),
+            port: target.port,
+        })
+        .collect::<Vec<_>>();
+    let permitted = readiness
+        .permitted
+        .iter()
+        .map(|target| TcpProbeTarget {
+            address: IpAddress::V4(target.address),
+            port: target.port,
+        })
+        .collect::<Vec<_>>();
+    let dns = readiness
+        .dns
+        .iter()
+        .map(|target| DnsProbeTarget {
+            resolver: IpAddress::V4(target.resolver),
+            query_name: target.query.clone(),
+        })
+        .collect::<Vec<_>>();
+    let reachability = ReachabilityExpectation {
+        denied_destinations: denied.iter().map(|target| target.address).collect(),
+        permitted_destinations: permitted.iter().map(|target| target.address).collect(),
+        dns_queries: dns
+            .iter()
+            .map(|target| DnsQueryExpectation {
+                resolver: target.resolver,
+                query_name: target.query_name.clone(),
+            })
+            .collect(),
+    };
+    let resolvers = dns
+        .iter()
+        .map(|target| target.resolver)
+        .collect::<BTreeSet<_>>()
+        .into_iter()
+        .collect();
+    (
+        resolvers,
+        NetworkProbeRequest {
+            domain_id: generation.domain_id,
+            generation_id: generation.generation_id,
+            enforcement_namespace,
+            denied,
+            permitted,
+            dns,
+        },
+        reachability,
+    )
+}
+
+fn open_installed_executable(path: &Path) -> Result<File, ProductionSelectionError> {
+    let descriptor = openat2(
+        rustix::fs::CWD,
+        path,
+        OFlags::RDONLY | OFlags::NOFOLLOW | OFlags::CLOEXEC,
+        Mode::empty(),
+        ResolveFlags::NO_MAGICLINKS | ResolveFlags::NO_SYMLINKS,
+    )
+    .map_err(failure)?;
+    let file = File::from(descriptor);
+    let metadata = file.metadata().map_err(failure)?;
+    if !metadata.is_file() || metadata.permissions().mode() & 0o111 == 0 {
+        return Err(failure(
+            "installed product path is not an executable regular file",
+        ));
+    }
+    Ok(file)
+}
+
+fn rootless_id_map() -> IdMap {
+    IdMap {
+        uid: vec![IdMapRange {
+            container_id: 0,
+            namespace_id: rustix::process::getuid().as_raw(),
+            size: 1,
+        }],
+        gid: vec![IdMapRange {
+            container_id: 0,
+            namespace_id: rustix::process::getgid().as_raw(),
+            size: 1,
+        }],
+    }
+}
+
+fn host_platform() -> Result<Platform, ProductionSelectionError> {
+    match std::env::consts::ARCH {
+        "x86_64" => Ok(Platform::linux("amd64")),
+        "aarch64" => Ok(Platform::linux("arm64")),
+        architecture => Err(failure(format!(
+            "host architecture {architecture} has no selected OCI platform mapping"
+        ))),
+    }
+}
+
+fn distinct_generation_ids()
+-> Result<(CoordinatorId, NetworkSidecarId, SandboxId), ProductionSelectionError> {
+    for _ in 0..8 {
+        let coordinator = CoordinatorId::new(random_id()?);
+        let network = NetworkSidecarId::new(random_id()?);
+        let sandbox = SandboxId::new(random_id()?);
+        if coordinator.as_bytes() != network.as_bytes()
+            && coordinator.as_bytes() != sandbox.as_bytes()
+            && network.as_bytes() != sandbox.as_bytes()
+        {
+            return Ok((coordinator, network, sandbox));
+        }
+    }
+    Err(failure(
+        "fresh generation role identities repeatedly collided",
+    ))
+}
+
+fn random_id() -> Result<[u8; 32], ProductionSelectionError> {
+    let mut bytes = [0; 32];
+    getrandom::fill(&mut bytes).map_err(failure)?;
+    Ok(bytes)
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::BTreeMap;
+    use std::fs;
+
+    use lazaret_core::configuration::{ConfigurationLoadRequest, load_trusted_configuration};
+    use lazaret_core::identity::{DeviceId, InodeId, NamespaceIdentity};
+    use lazaret_runtime_supervisor::sandbox::production_sandbox_layout;
+
+    use super::*;
+
+    #[test]
+    fn resolved_readiness_maps_exactly_and_rootless_id_map_matches_builder_policy() {
+        let tree = tempfile::tempdir().unwrap();
+        let configuration = configuration(tree.path());
+        let generation = Generation {
+            domain_id: configuration.domain_id(),
+            generation_id: GenerationId::new(9),
+            configuration_fingerprint: configuration.configuration_fingerprint(),
+            coordinator_id: CoordinatorId::new([1; 32]),
+            network_sidecar_id: NetworkSidecarId::new([2; 32]),
+            sandbox_id: SandboxId::new([3; 32]),
+            durable_decision: DurableDecision::None,
+        };
+        let namespace = NamespaceIdentity {
+            device: DeviceId::new(4),
+            inode: InodeId::new(5),
+        };
+        let (resolvers, request, expectation) =
+            select_network_readiness(&configuration, &generation, namespace);
+        assert_eq!(resolvers, [IpAddress::V4([198, 51, 100, 53])]);
+        assert_eq!(request.denied[0].port, 8443);
+        assert_eq!(request.permitted[0].port, 443);
+        assert_eq!(request.dns[0].query_name, "example.invalid");
+        assert_eq!(expectation.denied_destinations, [request.denied[0].address]);
+        assert_eq!(
+            expectation.permitted_destinations,
+            [request.permitted[0].address]
+        );
+        assert_eq!(expectation.dns_queries[0].resolver, request.dns[0].resolver);
+
+        let id_map = rootless_id_map();
+        assert_eq!(id_map.uid[0].container_id, 0);
+        assert_eq!(
+            id_map.uid[0].namespace_id,
+            rustix::process::getuid().as_raw()
+        );
+        assert_eq!(
+            id_map.gid[0].namespace_id,
+            rustix::process::getgid().as_raw()
+        );
+    }
+
+    #[test]
+    fn installed_product_selection_requires_exact_executable_and_fresh_roles() {
+        let tree = tempfile::tempdir().unwrap();
+        let executable = tree.path().join("product");
+        fs::copy("/bin/true", &executable).unwrap();
+        fs::set_permissions(&executable, fs::Permissions::from_mode(0o700)).unwrap();
+        assert!(open_installed_executable(&executable).is_ok());
+        fs::set_permissions(&executable, fs::Permissions::from_mode(0o600)).unwrap();
+        assert!(open_installed_executable(&executable).is_err());
+        let (coordinator, network, sandbox) = distinct_generation_ids().unwrap();
+        assert_ne!(coordinator.as_bytes(), network.as_bytes());
+        assert_ne!(coordinator.as_bytes(), sandbox.as_bytes());
+        assert_ne!(network.as_bytes(), sandbox.as_bytes());
+        assert!(host_platform().is_ok());
+    }
+
+    fn configuration(root: &Path) -> ResolvedDomainConfiguration {
+        let configuration_directory = root.join("configuration");
+        let workspace = root.join("workspace");
+        let runtime = root.join("runtime");
+        fs::create_dir(&configuration_directory).unwrap();
+        fs::create_dir(&workspace).unwrap();
+        fs::create_dir(&runtime).unwrap();
+        let configuration_path = configuration_directory.join("lazaret.toml");
+        fs::write(
+            &configuration_path,
+            format!(
+                "schema = \"lazaret-trusted-host-config-v1\"\n[storage]\ndata_root = \"{}\"\n[network]\ndefault_allow = [\"192.0.2.10/32\"]\n[profiles.default]\nimage = \"example.invalid/factory:v1\"\n[profiles.default.readiness]\ndenied = [{{ address = \"10.20.30.40\", port = 8443 }}]\npermitted = [{{ address = \"192.0.2.10\", port = 443 }}]\ndns = [{{ resolver = \"198.51.100.53\", query = \"Example.Invalid.\" }}]\n",
+                root.join("data").display()
+            ),
+        )
+        .unwrap();
+        load_trusted_configuration(ConfigurationLoadRequest {
+            explicit_configuration_path: Some(configuration_path),
+            selected_profile: "default".into(),
+            workspace,
+            home: root.join("home"),
+            xdg_config_home: None,
+            xdg_data_home: None,
+            xdg_runtime_dir: runtime,
+            environment: BTreeMap::new(),
+            sandbox_layout: production_sandbox_layout().unwrap(),
+        })
+        .unwrap()
+    }
+}

crates/lazaret-host-coordinator/src/sandbox_init.rs

@@ -0,0 +1,38 @@
+use std::ffi::{OsStr, OsString};
+
+pub const PRIVATE_SANDBOX_INIT_ROLE: &str = "--lazaret-private-sandbox-init-v1";
+
+#[must_use]
+pub fn is_private_sandbox_init_role(arguments: &[OsString]) -> bool {
+    arguments.len() == 1 && arguments[0] == OsStr::new(PRIVATE_SANDBOX_INIT_ROLE)
+}
+
+#[must_use]
+pub fn dispatch_private_sandbox_init(arguments: &[OsString]) -> bool {
+    if !is_private_sandbox_init_role(arguments) {
+        return false;
+    }
+    loop {
+        std::thread::park();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn private_role_dispatch_is_exact_and_closed() {
+        assert!(is_private_sandbox_init_role(&[OsString::from(
+            PRIVATE_SANDBOX_INIT_ROLE
+        )]));
+        assert!(!is_private_sandbox_init_role(&[]));
+        assert!(!is_private_sandbox_init_role(&[
+            OsString::from(PRIVATE_SANDBOX_INIT_ROLE),
+            OsString::from("extra"),
+        ]));
+        assert!(!is_private_sandbox_init_role(&[OsString::from(
+            "--private-sandbox-init"
+        )]));
+    }
+}

crates/lazaret-host-coordinator/src/state_anchor/tests.rs

@@ -577,7 +577,7 @@ fn configuration(tree: &TestTree) -> lazaret_core::configuration::ResolvedDomain
     fs::write(
         &configuration_path,
         format!(
-            "schema = \"lazaret-trusted-host-config-v1\"\n[storage]\ndata_root = \"{}\"\n[profiles.default]\nimage = \"example.invalid/fixture:v1\"\npersistent_dirs = [\"/usr\"]\n",
+            "schema = \"lazaret-trusted-host-config-v1\"\n[storage]\ndata_root = \"{}\"\n[network]\ndefault_allow = [\"192.0.2.10/32\"]\n[profiles.default]\nimage = \"example.invalid/fixture:v1\"\npersistent_dirs = [\"/usr\"]\n[profiles.default.readiness]\ndenied = [{{ address = \"10.20.30.40\", port = 443 }}]\npermitted = [{{ address = \"192.0.2.10\", port = 443 }}]\ndns = [{{ resolver = \"198.51.100.53\", query = \"example.invalid\" }}]\n",
             tree.path.join("data").display()
         ),
     )

crates/lazaret-host-coordinator/tests/production.rs

@@ -199,6 +199,7 @@ impl ProductionFixture {
             container_id: self.container_id,
             invoking_uid: getuid().as_raw(),
             escalation_client,
+            sandbox_init: escalation_client,
         }
     }
 
@@ -242,7 +243,7 @@ fn configuration(root: &Path) -> lazaret_core::configuration::ResolvedDomainConf
     fs::write(
         &configuration_path,
         format!(
-            "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[profiles.default]\nimage = \"example.invalid/factory:v1\"\npersistent_dirs = []\n",
+            "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[network]\ndefault_allow = [\"192.0.2.10/32\"]\n\n[profiles.default]\nimage = \"example.invalid/factory:v1\"\npersistent_dirs = []\n\n[profiles.default.readiness]\ndenied = [{{ address = \"10.20.30.40\", port = 443 }}]\npermitted = [{{ address = \"192.0.2.10\", port = 443 }}]\ndns = [{{ resolver = \"198.51.100.53\", query = \"example.invalid\" }}]\n",
             root.join("data").display()
         ),
     )

crates/lazaret-host-coordinator/tests/runtime-composition.rs

@@ -629,7 +629,7 @@ impl Fixture {
         fs::write(
             &configuration_path,
             format!(
-                "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[profiles.default]\nimage = \"example.invalid/runtime-fixture:v1\"\npersistent_dirs = [\"/tooling\", \"/fixtures\"]\nenv = {{ PATH = \"env:BENCHMARK_PATH\", CARGO_HOME = \"env:BENCHMARK_CARGO_HOME\", RUSTUP_HOME = \"env:BENCHMARK_RUSTUP_HOME\", CARGO_BUILD_JOBS = \"env:BENCHMARK_CARGO_BUILD_JOBS\" }}\nvolumes = [\n  {{ host = \"{}\", container = \"/tooling/usr\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/fixtures/host\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/fixtures/output\", kind = \"directory\", access = \"read-write\" }},\n  {{ host = \"{}\", container = \"/fixtures/repository\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/tooling/cargo\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/tooling/rustup\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/tooling/uv-bin\", kind = \"directory\", access = \"read-only\" }},\n]\n",
+                "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[network]\ndefault_allow = [\"192.0.2.10/32\"]\n\n[profiles.default]\nimage = \"example.invalid/runtime-fixture:v1\"\npersistent_dirs = [\"/tooling\", \"/fixtures\"]\nenv = {{ PATH = \"env:BENCHMARK_PATH\", CARGO_HOME = \"env:BENCHMARK_CARGO_HOME\", RUSTUP_HOME = \"env:BENCHMARK_RUSTUP_HOME\", CARGO_BUILD_JOBS = \"env:BENCHMARK_CARGO_BUILD_JOBS\" }}\nvolumes = [\n  {{ host = \"{}\", container = \"/tooling/usr\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/fixtures/host\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/fixtures/output\", kind = \"directory\", access = \"read-write\" }},\n  {{ host = \"{}\", container = \"/fixtures/repository\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/tooling/cargo\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/tooling/rustup\", kind = \"directory\", access = \"read-only\" }},\n  {{ host = \"{}\", container = \"/tooling/uv-bin\", kind = \"directory\", access = \"read-only\" }},\n]\n\n[profiles.default.readiness]\ndenied = [{{ address = \"10.20.30.40\", port = 443 }}]\npermitted = [{{ address = \"192.0.2.10\", port = 443 }}]\ndns = [{{ resolver = \"198.51.100.53\", query = \"example.invalid\" }}]\n",
                 root.join("data").display(),
                 Path::new("/usr").display(),
                 host_root.display(),
@@ -708,7 +708,7 @@ impl Fixture {
         fs::write(
             &configuration_path,
             format!(
-                "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[profiles.default]\nimage = \"example.invalid/runtime-fixture:v1\"\npersistent_dirs = []\n",
+                "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[network]\ndefault_allow = [\"192.0.2.10/32\"]\n\n[profiles.default]\nimage = \"example.invalid/runtime-fixture:v1\"\npersistent_dirs = []\n\n[profiles.default.readiness]\ndenied = [{{ address = \"10.20.30.40\", port = 443 }}]\npermitted = [{{ address = \"192.0.2.10\", port = 443 }}]\ndns = [{{ resolver = \"198.51.100.53\", query = \"example.invalid\" }}]\n",
                 root.join("data").display()
             ),
         )?;
@@ -1026,7 +1026,7 @@ fn network_configuration(
     fs::write(
         &configuration_path,
         format!(
-            "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[profiles.default]\nimage = \"example.invalid/network-fixture:v1\"\npersistent_dirs = []\n",
+            "schema = \"lazaret-trusted-host-config-v1\"\n\n[storage]\ndata_root = \"{}\"\n\n[network]\ndefault_allow = [\"192.0.2.10/32\"]\n\n[profiles.default]\nimage = \"example.invalid/network-fixture:v1\"\npersistent_dirs = []\n\n[profiles.default.readiness]\ndenied = [{{ address = \"10.20.30.40\", port = 443 }}]\npermitted = [{{ address = \"192.0.2.10\", port = 443 }}]\ndns = [{{ resolver = \"198.51.100.53\", query = \"example.invalid\" }}]\n",
             root.join("data").display()
         ),
     )?;