fix: complete durable workspace runtime config handoff

backend/src/tht/tht-runner.ts

@@ -322,29 +322,40 @@ export class ThtRunner {
       }
       let snapshotFd: number | undefined;
       let canonicalFd: number | undefined;
+      let manifestFd: number | undefined;
       let ch;
       try {
         snapshotFd = workspaceConfigPath && this.runtimeSnapshots.has(workspaceConfigPath)
           ? this.openTrustedRuntimeSnapshot(workspaceConfigPath) : undefined;
-        // Runtime lease publication is durable, but the child must consume the verified
-        // bytes rather than reopening a mutable pathname after spawn. Keep canonical -c
-        // for CLI compatibility and hand the same open file as fd 3.
-        canonicalFd = snapshotFd === undefined && workspaceConfigPath && this.runtimeLeases.has(workspaceConfigPath)
-          ? openSync(workspaceConfigPath, fsConstants.O_RDONLY | fsConstants.O_NOFOLLOW) : undefined;
+        const lease = workspaceConfigPath ? this.runtimeLeases.get(workspaceConfigPath) : undefined;
+        // Registry leases retain the verified config bytes in fd 3 and the separately
+        // published manifest in fd 4. The argv remains the canonical -c pathname for
+        // diagnostics/compatibility; the harness never trusts that pathname for bytes.
+        canonicalFd = snapshotFd === undefined && lease
+          ? openSync(lease.path, fsConstants.O_RDONLY | fsConstants.O_NOFOLLOW) : undefined;
+        manifestFd = lease
+          ? openSync(lease.manifestPath, fsConstants.O_RDONLY | fsConstants.O_NOFOLLOW) : undefined;
+        if (lease) {
+          env.THT_CONFIG_FD = "3";
+          env.THT_CONFIG_MANIFEST_FD = "4";
+          env.THT_CONFIG_MANIFEST_SHA256 = lease.manifestSha256;
+        }
         const handoffFd = snapshotFd ?? canonicalFd;
-        if (canonicalFd !== undefined) env.THT_CONFIG_FD = "3";
         ch = spawn(
           this.cfg.thtBin,
           snapshotFd === undefined ? this.buildArgv(args, workspaceConfigPath) : [...args, "-c", "/dev/fd/3"],
           {
             cwd: this.cfg.harnessDir,
             env,
-            ...(handoffFd === undefined ? {} : { stdio: ["ignore", "pipe", "pipe", handoffFd] }),
+            ...(handoffFd === undefined ? {} : {
+              stdio: ["ignore", "pipe", "pipe", handoffFd, ...(manifestFd === undefined ? [] : [manifestFd])],
+            }),
           },
         );
       } finally {
         if (snapshotFd !== undefined) closeSync(snapshotFd);
         if (canonicalFd !== undefined) closeSync(canonicalFd);
+        if (manifestFd !== undefined) closeSync(manifestFd);
       }
       let stdout = "";
       let stderr = "";

backend/src/workspaces/runtime-config-lease.ts

@@ -3,8 +3,7 @@ import { spawnSync } from "node:child_process";
 import { isIP } from "node:net";
 import { domainToASCII } from "node:url";
 import {
-  closeSync, constants as fsConstants, fstatSync, lstatSync,
-  existsSync, mkdirSync, openSync, readFileSync,
+  existsSync, lstatSync, readFileSync,
 } from "node:fs";
 import { dirname, isAbsolute, join, relative, resolve } from "node:path";
 import { parseAllDocuments } from "yaml";
@@ -20,6 +19,8 @@ import { parseWorkspaceYaml, validateOperationalWorkspace, type WorkspaceDescrip
 export interface RuntimeConfigLease {
   path: string;
   manifestPath: string;
+  /** SHA-256 of the exact durable manifest bytes handed to the child. */
+  manifestSha256: string;
   workspaceId: string;
   workspaceRevision: string;
   release(): void;
@@ -53,12 +54,13 @@ interface SnapshotIdentity {
 interface PublishedIdentity {
   path: string;
   manifestPath: string;
+  /** SHA-256 of the exact durable manifest bytes handed to the child. */
+  manifestSha256: string;
   workspaceId: string;
   workspaceRevision: string;
   digest: string;
   content: string;
   manifest: string;
-  refs: number;
 }
 
 
@@ -119,11 +121,12 @@ export class WorkspaceRuntimeConfigLeaseFactory {
   private readonly env: NodeJS.ProcessEnv;
   private readonly secretRoots: readonly string[];
   private readonly installation: RuntimeInstallationOverlay;
-  private readonly published = new Map<string, PublishedIdentity>();
 
   constructor(private readonly input: WorkspaceRuntimeConfigLeaseFactoryInput) {
     if (!isAbsolute(input.dataRoot) || !isAbsolute(input.runtimeSnapshotRoot)) throw new Error("workspace runtime roots must be absolute");
-    if (!existsSync(input.runtimeSnapshotRoot)) mkdirSync(input.runtimeSnapshotRoot, { recursive: true, mode: 0o700 });
+    // Registry snapshots are produced by WorkspaceRegistry. Never recursively
+    // create this security boundary from a pathname (an ancestor could be swapped).
+    if (!existsSync(input.runtimeSnapshotRoot)) throw new Error("runtime snapshot root is unavailable");
     this.assertDirectory(input.runtimeSnapshotRoot, "runtime snapshot root");
     this.env = { ...(input.env ?? process.env) };
     this.secretRoots = [...(input.secretRoots ?? [])];
@@ -149,7 +152,7 @@ export class WorkspaceRuntimeConfigLeaseFactory {
     const renderedDigest = digest(rendered);
     const base = {
       workspace_id: snapshot.workspaceId, workspace_revision: snapshot.workspaceRevision,
-      descriptor_git_blob: snapshot.descriptorBlob ?? "unknown",
+      descriptor_git_blob: snapshot.descriptorBlob!,
       descriptor_sha256: snapshot.digest,
       config_sha256: renderedDigest,
       config_dwh_binding: this.computeBinding(rendered),
@@ -158,9 +161,8 @@ export class WorkspaceRuntimeConfigLeaseFactory {
     const identity: PublishedIdentity = {
       path: result.path, manifestPath: result.manifestPath, workspaceId: snapshot.workspaceId,
       workspaceRevision: snapshot.workspaceRevision, digest: renderedDigest, content: rendered,
-      manifest: result.manifest, refs: 1,
+      manifest: result.manifest, manifestSha256: result.manifest_sha256,
     };
-    this.published.set(identity.path, identity);
     return this.lease(identity);
   }
 
@@ -194,14 +196,14 @@ export class WorkspaceRuntimeConfigLeaseFactory {
     return { workspace_id: "unknown", config_fingerprint: `sha256:${digest(content)}`, input_fingerprint: `sha256:${digest(content)}` };
   }
 
-  private publishSecure(workspaceId: string, revision: string, content: string, manifestBase: Record<string, unknown>): {path:string; manifestPath:string; manifest:string} {
+  private publishSecure(workspaceId: string, revision: string, content: string, manifestBase: Record<string, unknown>): {path:string; manifestPath:string; manifest:string; manifest_sha256:string} {
     return this.helper("publish", { data_root: this.input.dataRoot, workspace_id: workspaceId,
       workspace_revision: revision, config_hex: Buffer.from(content).toString("hex"), manifest_base: manifestBase });
   }
 
   private lease(identity: PublishedIdentity): RuntimeConfigLease {
     let released = false;
-    return { path: identity.path, manifestPath: identity.manifestPath, workspaceId: identity.workspaceId, workspaceRevision: identity.workspaceRevision,
+    return { path: identity.path, manifestPath: identity.manifestPath, manifestSha256: identity.manifestSha256, workspaceId: identity.workspaceId, workspaceRevision: identity.workspaceRevision,
       release: () => { if (released) return; released = true; /* Durable revision-owned state: release only drops our local handle/ref. */ }, };
   }
 
@@ -217,31 +219,30 @@ export class WorkspaceRuntimeConfigLeaseFactory {
 
   private readSnapshot(path: string): SnapshotIdentity {
     if (!isAbsolute(path)) throw new Error("workspace snapshot path must be absolute");
-    const rel = relative(this.input.runtimeSnapshotRoot, path);
+    const root = resolve(this.input.runtimeSnapshotRoot);
+    const rel = relative(root, path);
     const match = /^([0-9a-f]{40})\/([a-z][a-z0-9-]{2,62})\.yaml$/.exec(rel);
     if (!match || rel.startsWith("..") || isAbsolute(rel)) throw new Error("config path is not a trusted runtime snapshot");
-    this.assertDirectory(join(this.input.runtimeSnapshotRoot, match[1]), "workspace snapshot parent");
-    const fd = openSync(path, fsConstants.O_RDONLY | fsConstants.O_NOFOLLOW);
-    try {
-      const before = fstatSync(fd);
-      if (!before.isFile() || before.nlink !== 1 || (before.mode & 0o077) !== 0) throw new Error("workspace snapshot is not a trusted file");
-      const source = readFileSync(fd, "utf8");
-      const after = fstatSync(fd);
-      if (before.dev !== after.dev || before.ino !== after.ino || before.size !== after.size) throw new Error("workspace snapshot changed while reading");
-      const workspace = validateOperationalWorkspace(parseWorkspaceYaml(source));
-      if (workspace.workspace.id !== match[2]) throw new Error("workspace snapshot identity does not match its path");
-      let descriptorBlob: string | undefined;
-      const repositoryRoot = join(dirname(this.input.runtimeSnapshotRoot), "repo");
-      const verified = this.helper("verified-snapshot", { snapshots_root: this.input.runtimeSnapshotRoot, ...(existsSync(repositoryRoot) ? { repository_root: repositoryRoot } : {}), workspace_revision: match[1], workspace_id: match[2] });
-      if (!verified || verified.sha256 !== digest(source) || verified.source !== source) throw new Error("workspace snapshot integrity check failed");
-      const manifestPath = join(this.input.runtimeSnapshotRoot, match[1], "snapshot.json");
-      if (!existsSync(manifestPath)) throw new Error("workspace snapshot integrity check failed");
-      const manifest = JSON.parse(readFileSync(manifestPath, "utf8")) as any;
-      const record = Array.isArray(manifest.revisions) ? manifest.revisions.find((r: any) => r?.id === match[2]) : undefined;
-      const expectedFile = `${match[2]}.yaml`;
-      if (manifest.head !== match[1] || !record || record.commit !== match[1] || record.snapshotPath !== path || typeof record.blob !== "string" || manifest.files?.[expectedFile] !== digest(source)) throw new Error("workspace snapshot integrity check failed");
-      descriptorBlob = record.blob;
-      return { workspace, workspaceId: match[2], workspaceRevision: match[1], revisionContentRoot: dirname(path), digest: digest(source), descriptorBlob };
-    } finally { closeSync(fd); }
+    // The helper is the canonical registry capability boundary. It opens the exact
+    // production snapshot.json and descriptor component-by-component, and MUST prove
+    // the Git commit/blob identity; a pathname-shaped file is never sufficient.
+    const repositoryRoot = join(dirname(root), "repo");
+    const verified = this.helper("verified-snapshot", {
+      snapshots_root: root, repository_root: repositoryRoot,
+      workspace_revision: match[1], workspace_id: match[2],
+    });
+    if (!verified || typeof verified.source !== "string"
+      || verified.sha256 !== digest(verified.source) || verified.snapshot_path !== path) {
+      throw new Error("workspace snapshot integrity check failed");
+    }
+    const workspace = validateOperationalWorkspace(parseWorkspaceYaml(verified.source));
+    if (workspace.workspace.id !== match[2] || typeof verified.descriptor_git_blob !== "string") {
+      throw new Error("workspace snapshot integrity check failed");
+    }
+    return {
+      workspace, workspaceId: match[2], workspaceRevision: match[1],
+      revisionContentRoot: join(root, match[1]), digest: verified.sha256,
+      descriptorBlob: verified.descriptor_git_blob,
+    };
   }
 }

backend/test/workspace-runtime-config-lease.test.ts

@@ -1,10 +1,11 @@
 import { test, expect } from "vitest";
 import { chmodSync, existsSync, lstatSync, mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
-import { dirname, join } from "node:path";
+import { join } from "node:path";
+import { execFileSync } from "node:child_process";
+import { createHash } from "node:crypto";
 import { WorkspaceRuntimeConfigLeaseFactory } from "../src/workspaces/runtime-config-lease.js";
 
-const commit = "a".repeat(40);
 const workspace = "abc";
 const descriptor = `workspace:
   schema_version: 3
@@ -33,11 +34,27 @@ llm_policy:
 function fixture() {
   const root = mkdtempSync(join(tmpdir(), "runtime-config-lease-"));
   const snapshots = join(root, "snapshots");
-  const snapshotPath = join(snapshots, commit, `${workspace}.yaml`);
+  const repo = join(root, "repo");
+  mkdirSync(join(repo, "workspaces"), { recursive: true });
+  execFileSync("git", ["init", "--initial-branch=main"], { cwd: repo });
+  execFileSync("git", ["config", "user.name", "Fixture"], { cwd: repo });
+  execFileSync("git", ["config", "user.email", "fixture@example.invalid"], { cwd: repo });
+  writeFileSync(join(repo, "workspaces", `${workspace}.yaml`), descriptor);
+  execFileSync("git", ["add", "."], { cwd: repo });
+  execFileSync("git", ["commit", "-m", "fixture"], { cwd: repo });
+  const actualCommit = execFileSync("git", ["rev-parse", "HEAD"], { cwd: repo, encoding: "utf8" }).trim();
+  const blob = execFileSync("git", ["rev-parse", `HEAD:workspaces/${workspace}.yaml`], { cwd: repo, encoding: "utf8" }).trim();
+  const snapshotsDir = join(snapshots, actualCommit);
+  const snapshotPath = join(snapshotsDir, `${workspace}.yaml`);
   const dataRoot = join(root, "data");
   const harness = join(root, "harness");
-  mkdirSync(join(snapshots, commit), { recursive: true, mode: 0o700 });
+  mkdirSync(snapshotsDir, { recursive: true, mode: 0o700 });
   chmodSync(snapshots, 0o700);
+  writeFileSync(join(snapshotsDir, "snapshot.json"), JSON.stringify({
+    head: actualCommit,
+    revisions: [{ id: workspace, commit: actualCommit, blob, snapshotPath }],
+    files: { [`${workspace}.yaml`]: createHash("sha256").update(descriptor).digest("hex") },
+  }), { mode: 0o400 });
   mkdirSync(harness);
   writeFileSync(snapshotPath, descriptor, { mode: 0o400 });
   const secret = join(root, "password");
@@ -66,9 +83,9 @@ test("session and maintenance share deterministic bytes and path", () => {
     expect(session.path).toBe(maintenance.path);
     expect(readFileSync(session.path, "utf8")).toBe(readFileSync(maintenance.path, "utf8"));
     expect(lstatSync(session.path).mode & 0o777).toBe(0o400);
-    expect(existsSync(join(dirname(session.path), `${commit}.manifest.json`))).toBe(true);
+    expect(existsSync(maintenance.manifestPath)).toBe(true);
     session.release(); maintenance.release();
-    expect(existsSync(session.path)).toBe(false);
+    expect(existsSync(session.path)).toBe(true);
   } finally { rmSync(f.root, { recursive: true, force: true }); }
 });
 

backend/test/workspace-runtime-handoff.test.ts

@@ -101,7 +101,8 @@ async function fixture(workspaceSource = filesystemWorkspace) {
     writeFileSync(path, contents, { mode: 0o600 });
     chmodSync(path, 0o600);
   }
-  mkdirSync(dataRoot);
+  mkdirSync(dataRoot, { mode: 0o700 });
+  chmodSync(dataRoot, 0o700);
   const registryConfig: WorkspaceRegistryConfig = {
     root: registryRoot,
     remoteUrl: remote,
@@ -138,7 +139,7 @@ function runnerFor(f: Awaited<ReturnType<typeof fixture>>): ThtRunner {
     harnessDir,
     configPath: "config/tht.yaml",
     dataRoot: f.dataRoot,
-    runtimeSnapshotRoot: join(f.registryConfig.root, "snapshots", "runtime"),
+    runtimeSnapshotRoot: join(f.registryConfig.root, "snapshots"),
     secretRoots: f.registryConfig.secretRoots,
   } as any);
 }
@@ -162,7 +163,7 @@ test("real schema-v3 registry revision loads through ThtRunner and the harness c
   expect(existsSync(join(
     f.dataRoot, "sessions", "psd-clinical", "sessions", created.id, "session_manifest.yaml",
   ))).toBe(true);
-  expect(readdirSync(join(f.registryConfig.root, "snapshots", "runtime"))).toEqual([]);
+  expect(readdirSync(join(f.registryConfig.root, "snapshots"))).toContain(f.revision.commit);
 });
 
 test("separate runtime leases hand off byte-identical revision Evidence configs accepted by tht", async () => {
@@ -215,7 +216,7 @@ test("separate runtime leases hand off byte-identical revision Evidence configs
     expect(existsSync(first.path)).toBe(true);
     expect(existsSync(second.path)).toBe(true);
     second.release();
-    expect(existsSync(second.path)).toBe(false);
+    expect(existsSync(second.path)).toBe(true);
   } finally {
     first.release();
     second.release();

harness/tht/config.py

@@ -1,3 +1,4 @@
+import hashlib
 import json
 import os
 import re
@@ -572,25 +573,80 @@ def _validate_raw_config_shape(raw: dict[str, Any], path: Path) -> None:
                 )
 
 
+def _read_runtime_fd(fd: int, label: str, expected_mode: int = 0o400) -> tuple[bytes, os.stat_result]:
+    try:
+        info = os.fstat(fd)
+        if (not stat.S_ISREG(info.st_mode) or info.st_nlink != 1
+                or stat.S_IMODE(info.st_mode) != expected_mode
+                or info.st_uid != os.getuid()):
+            raise OSError("unsafe runtime descriptor")
+        os.lseek(fd, 0, os.SEEK_SET)
+        chunks: list[bytes] = []
+        total = 0
+        while chunk := os.read(fd, 1024 * 1024):
+            total += len(chunk)
+            if total > 16 * 1024 * 1024:
+                raise OSError("runtime descriptor too large")
+            chunks.append(chunk)
+        return b"".join(chunks), info
+    except OSError as exc:
+        raise ConfigError(f"File runtime {label} non attendibile") from exc
+
+
+def _strict_runtime_manifest(raw: object) -> dict[str, object]:
+    required = {
+        "version", "workspace_id", "workspace_revision", "descriptor_git_blob",
+        "descriptor_sha256", "config_sha256", "config_dwh_binding", "config_dev",
+        "config_ino", "config_size", "config_mode", "config_uid", "config_nlink",
+    }
+    if not isinstance(raw, dict) or set(raw) != required or raw.get("version") != 1:
+        raise ConfigError("Manifest runtime non valido")
+    if not isinstance(raw.get("config_dwh_binding"), dict):
+        raise ConfigError("Manifest runtime non valido")
+    binding = raw["config_dwh_binding"]
+    if set(binding) != {"workspace_id", "config_fingerprint", "input_fingerprint"} or any(not isinstance(v, str) for v in binding.values()):
+        raise ConfigError("Manifest runtime non valido")
+    for key in ("descriptor_sha256", "config_sha256"):
+        if not isinstance(raw[key], str) or not re.fullmatch(r"[0-9a-f]{64}", raw[key]):
+            raise ConfigError("Manifest runtime non valido")
+    for key in ("config_dev", "config_ino", "config_size", "config_uid", "config_nlink"):
+        if not isinstance(raw[key], str) or not raw[key].isdigit():
+            raise ConfigError("Manifest runtime non valido")
+    if raw["config_mode"] != "400":
+        raise ConfigError("Manifest runtime non valido")
+    return raw
+
+
 def load_config(path: Path) -> Config:
     # Backend runtime leases pass the verified canonical config as fd 3 while retaining
     # the ordinary absolute -c argument for diagnostics and source identity.  Never reopen
     # that pathname: an ancestor or leaf replacement after spawn must not alter bytes used
     # by the harness.
+    runtime_manifest: dict[str, object] | None = None
     runtime_fd = os.environ.get("THT_CONFIG_FD")
-    if runtime_fd is not None:
+    manifest_fd = os.environ.get("THT_CONFIG_MANIFEST_FD")
+    expected_manifest = os.environ.get("THT_CONFIG_MANIFEST_SHA256")
+    if runtime_fd is not None or manifest_fd is not None or expected_manifest is not None:
+        if runtime_fd is None or manifest_fd is None or expected_manifest is None or not re.fullmatch(r"[0-9a-f]{64}", expected_manifest):
+            raise ConfigError("Handoff runtime incompleto")
         try:
-            fd = int(runtime_fd)
-            info = os.fstat(fd)
-            if (not stat.S_ISREG(info.st_mode) or info.st_nlink != 1
-                    or stat.S_IMODE(info.st_mode) != 0o400
-                    or info.st_uid != os.getuid()):
-                raise OSError("unsafe runtime config descriptor")
-            chunks: list[bytes] = []
-            while chunk := os.read(fd, 1024 * 1024):
-                chunks.append(chunk)
-            source_text = b"".join(chunks).decode("utf-8")
-        except (OSError, UnicodeError, ValueError) as exc:
+            config_bytes, config_info = _read_runtime_fd(int(runtime_fd), "config")
+            manifest_bytes, manifest_info = _read_runtime_fd(int(manifest_fd), "manifest", 0o600)
+            if hashlib.sha256(manifest_bytes).hexdigest() != expected_manifest:
+                raise ConfigError("Manifest runtime modificato")
+            runtime_manifest = _strict_runtime_manifest(json.loads(manifest_bytes.decode("utf-8")))
+            if (runtime_manifest["config_sha256"] != hashlib.sha256(config_bytes).hexdigest()
+                    or int(runtime_manifest["config_dev"]) != config_info.st_dev
+                    or int(runtime_manifest["config_ino"]) != config_info.st_ino
+                    or int(runtime_manifest["config_size"]) != config_info.st_size
+                    or int(runtime_manifest["config_uid"]) != config_info.st_uid
+                    or int(runtime_manifest["config_nlink"]) != config_info.st_nlink
+                    or config_info.st_dev == manifest_info.st_dev and config_info.st_ino == manifest_info.st_ino):
+                raise ConfigError("Identità config runtime non valida")
+            source_text = config_bytes.decode("utf-8")
+        except (OSError, UnicodeError, ValueError, json.JSONDecodeError) as exc:
+            if isinstance(exc, ConfigError):
+                raise
             raise ConfigError("File di configurazione runtime non attendibile") from exc
     else:
         if not path.exists():
@@ -679,6 +735,12 @@ def load_config(path: Path) -> Config:
     )
     _validate_active_embeddings_config(cfg.embeddings, path)
     _validate_active_vector_config(cfg.vectors, path)
+    if runtime_manifest is not None:
+        from tht.jobs.dwh_pipeline import config_dwh_binding
+        if runtime_manifest["workspace_id"] != cfg._workspace_id or runtime_manifest["workspace_revision"] != cfg._workspace_revision:
+            raise ConfigError("Identità workspace runtime non valida")
+        if config_dwh_binding(cfg) != runtime_manifest["config_dwh_binding"]:
+            raise ConfigError("Binding DWH runtime modificato")
     return cfg
 
 

harness/tht/runtime_config_lease_io.py

@@ -26,8 +26,16 @@ def safe_rev(v: str) -> bool:
 
 
 def open_dir(parent: int | None, name: str, create: bool = False) -> int:
-    flags = os.O_RDONLY | getattr(os, "O_DIRECTORY", 0) | os.O_NOFOLLOW
+    # Darwin rejects O_NOFOLLOW|openat for directories (ELOOP); lstat the
+    # component before opening and verify the resulting descriptor below. Linux
+    # uses the stronger flag where available.
+    flags = os.O_RDONLY | getattr(os, "O_DIRECTORY", 0)
+    if sys.platform != "darwin":
+        flags |= os.O_NOFOLLOW
     try:
+        entry = os.stat(name, dir_fd=parent, follow_symlinks=False)
+        if stat.S_ISLNK(entry.st_mode):
+            fail("runtime config directory is not trusted")
         return os.open(name, flags, dir_fd=parent)
     except FileNotFoundError:
         if not create:
@@ -48,25 +56,39 @@ def checked_dir(fd: int, expected_mode: int = 0o700) -> None:
 
 
 def walk(root: str, comps: list[str], create: bool = True) -> int:
+    """Open an absolute path component-by-component without following symlinks.
+
+    In particular, never use os.makedirs/root pathname resolution here: an attacker
+    replacing an ancestor between those calls must not redirect publication.
+    """
     if not os.path.isabs(root):
         fail("data root must be absolute")
-    if not os.path.lexists(root):
-        os.makedirs(root, mode=0o700, exist_ok=True)
-    fd = os.open(root, os.O_RDONLY | getattr(os, "O_DIRECTORY", 0) | os.O_NOFOLLOW)
+    # macOS exposes temporary directories through the conventional /var and
+    # /tmp symlinks. Resolve only these OS-owned aliases; workspace-owned
+    # ancestors remain component checked and are never realpath-followed.
+    if root == "/var" or root == "/tmp" or root.startswith(("/var/", "/tmp/")):
+        root = "/private" + root
+    parts = [part for part in Path(root).parts if part not in ("", "/")]
+    if any(part in (".", "..") or "/" in part for part in parts + comps):
+        fail("unsafe path component")
+    fd = os.open("/", os.O_RDONLY | getattr(os, "O_DIRECTORY", 0))
     try:
-        checked_dir(fd)
-    except:
+        all_components = [*parts, *comps]
+        for index, component in enumerate(all_components):
+            nxt = open_dir(fd, component, create)
+            # Ancestors such as /var/folders are installation-owned and commonly
+            # 0755; the trusted runtime root and every workspace child are private.
+            info = os.fstat(nxt)
+            if (not stat.S_ISDIR(info.st_mode) or info.st_nlink < 1
+                    or (index >= len(parts) - 1 and (info.st_uid != os.getuid() or stat.S_IMODE(info.st_mode) != 0o700))):
+                os.close(nxt)
+                fail("runtime config directory is not trusted")
+            os.close(fd)
+            fd = nxt
+        return fd
+    except BaseException:
         os.close(fd)
         raise
-    for c in comps:
-        if c in ("", ".", "..") or "/" in c:
-            os.close(fd)
-            fail("unsafe path component")
-        nxt = open_dir(fd, c, create)
-        checked_dir(nxt)
-        os.close(fd)
-        fd = nxt
-    return fd
 
 
 def read_regular(fd: int, mode: int, expected: bytes | None = None) -> os.stat_result:
@@ -100,6 +122,48 @@ def write_all(fd: int, data: bytes) -> None:
         pos += n
 
 
+def read_all(fd: int, limit: int = 16 * 1024 * 1024) -> bytes:
+    os.lseek(fd, 0, os.SEEK_SET)
+    chunks: list[bytes] = []
+    total = 0
+    while True:
+        chunk = os.read(fd, min(1024 * 1024, limit - total))
+        if not chunk:
+            return b"".join(chunks)
+        chunks.append(chunk)
+        total += len(chunk)
+        if total > limit:
+            fail("runtime config file is too large")
+
+
+def strict_manifest(value: object) -> dict:
+    if not isinstance(value, dict):
+        fail("runtime config manifest is invalid")
+    required = {
+        "version", "workspace_id", "workspace_revision", "descriptor_git_blob",
+        "descriptor_sha256", "config_sha256", "config_dwh_binding", "config_dev",
+        "config_ino", "config_size", "config_mode", "config_uid", "config_nlink",
+    }
+    if set(value) != required or value.get("version") != 1:
+        fail("runtime config manifest is invalid")
+    if not safe_id(value.get("workspace_id")) or not safe_rev(value.get("workspace_revision")):
+        fail("runtime config manifest is invalid")
+    if not isinstance(value.get("descriptor_git_blob"), str) or not safe_rev(value["descriptor_git_blob"]):
+        fail("runtime config manifest is invalid")
+    for key in ("descriptor_sha256", "config_sha256"):
+        if not isinstance(value[key], str) or not __import__("re").fullmatch(r"[0-9a-f]{64}", value[key]):
+            fail("runtime config manifest is invalid")
+    binding_value = value.get("config_dwh_binding")
+    if not isinstance(binding_value, dict) or set(binding_value) != {"workspace_id", "config_fingerprint", "input_fingerprint"} or any(not isinstance(x, str) for x in binding_value.values()):
+        fail("runtime config manifest is invalid")
+    for key in ("config_dev", "config_ino", "config_size", "config_uid", "config_nlink"):
+        if not isinstance(value[key], str) or not value[key].isdigit():
+            fail("runtime config manifest is invalid")
+    if value["config_mode"] != "400":
+        fail("runtime config manifest is invalid")
+    return value
+
+
 def publish(inp: dict) -> dict:
     root = inp.get("data_root")
     wid = inp.get("workspace_id")
@@ -160,7 +224,7 @@ def publish(inp: dict) -> dict:
         if got:
             fd, s = got
             os.lseek(fd, 0, os.SEEK_SET)
-            old = os.read(fd, len(content) + 1)
+            old = read_all(fd)
             os.close(fd)
             if old != content:
                 fail("same-revision runtime configuration changed")
@@ -179,6 +243,10 @@ def publish(inp: dict) -> dict:
                     )
                 except FileExistsError:
                     pass
+                # Keep metadata ordering explicit even on filesystems where a
+                # hardlink publication does not retain fchmod as expected.
+                os.fchmod(fd, 0o400)
+                os.fsync(fd)
             finally:
                 os.close(fd)
                 try:
@@ -191,7 +259,7 @@ def publish(inp: dict) -> dict:
             fd, s = got
             try:
                 os.lseek(fd, 0, os.SEEK_SET)
-                if os.read(fd, len(content) + 1) != content:
+                if read_all(fd) != content:
                     fail("same-revision runtime configuration changed")
             finally:
                 os.close(fd)
@@ -201,7 +269,7 @@ def publish(inp: dict) -> dict:
         assert got
         fd, s = got
         os.close(fd)
-        manifest = dict(base)
+        manifest = {"version": 1, **dict(base)}
         manifest.update(
             {
                 "config_sha256": hashlib.sha256(content).hexdigest(),
@@ -213,13 +281,16 @@ def publish(inp: dict) -> dict:
                 "config_nlink": str(s.st_nlink),
             }
         )
+        strict_manifest(manifest)
         mb = (json.dumps(manifest, sort_keys=True, separators=(",", ":")) + "\n").encode()
         oldm = current(mandir, mname, 0o600)
         if oldm:
             mfd, _ = oldm
             os.lseek(mfd, 0, os.SEEK_SET)
-            existing = os.read(mfd, len(mb) + 1)
+            existing = read_all(mfd)
             os.close(mfd)
+            try: strict_manifest(json.loads(existing.decode()))
+            except (ValueError, TypeError, UnicodeError, RuntimeError): fail("runtime config manifest is invalid")
             if existing != mb:
                 fail("same-revision runtime configuration changed")
         else:
@@ -245,6 +316,7 @@ def publish(inp: dict) -> dict:
             "path": f"{root}/sessions/{wid}/preprocessing/runtime-config/{name}",
             "manifestPath": f"{root}/sessions/{wid}/preprocessing/runtime-config-manifests/{mname}",
             "manifest": mb.decode(),
+            "manifest_sha256": hashlib.sha256(mb).hexdigest(),
             "dev": s.st_dev,
             "ino": s.st_ino,
         }
@@ -295,35 +367,53 @@ def verified_snapshot(inp: dict) -> dict:
             payload += x
     finally:
         os.close(mf)
-    manifest = json.loads(payload.decode())
-    record = next((r for r in manifest.get("revisions", []) if r.get("id") == wid), None)
+    try:
+        manifest = json.loads(payload.decode())
+    except (UnicodeDecodeError, json.JSONDecodeError):
+        fail("workspace snapshot integrity check failed")
+    if not isinstance(manifest, dict) or set(manifest) != {"head", "revisions", "files"}:
+        fail("workspace snapshot integrity check failed")
+    records = manifest.get("revisions")
+    files = manifest.get("files")
+    record = next((r for r in records if isinstance(r, dict) and r.get("id") == wid), None) if isinstance(records, list) else None
+    expected_path = f"{root}/{rev}/{wid}.yaml"
     if (
-        manifest.get("head") != rev
-        or not record
-        or record.get("commit") != rev
-        or manifest.get("files", {}).get(f"{wid}.yaml") != hashlib.sha256(source).hexdigest()
+        manifest.get("head") != rev or not isinstance(records, list) or not record
+        or set(record) != {"id", "commit", "blob", "snapshotPath"}
+        or record.get("commit") != rev or record.get("snapshotPath") != expected_path
+        or not isinstance(record.get("blob"), str) or not safe_rev(record.get("blob"))
+        or not isinstance(files, dict)
+        or files.get(f"{wid}.yaml") != hashlib.sha256(source).hexdigest()
     ):
         fail("workspace snapshot integrity check failed")
     repo = inp.get("repository_root")
-    if repo:
-        if not isinstance(repo, str) or not os.path.isabs(repo):
-            fail("invalid repository root")
-        try:
-            blob = subprocess.check_output(
-                ["git", "-C", repo, "rev-parse", f"{rev}:workspaces/{wid}.yaml"],
-                stderr=subprocess.DEVNULL,
-                text=True,
-                timeout=5,
-            ).strip()
-            git_source = subprocess.check_output(
-                ["git", "-C", repo, "show", f"{rev}:workspaces/{wid}.yaml"],
-                stderr=subprocess.DEVNULL,
-                timeout=5,
-            )
-        except (OSError, subprocess.SubprocessError):
-            fail("workspace Git revision is unavailable")
-        if blob != record.get("blob") or git_source != source:
-            fail("workspace Git descriptor identity mismatch")
+    if not isinstance(repo, str) or not os.path.isabs(repo):
+        fail("invalid repository root")
+    try:
+        blob = subprocess.check_output(
+            ["git", "-C", repo, "rev-parse", f"{rev}:workspaces/{wid}.yaml"],
+            stderr=subprocess.DEVNULL, text=True, timeout=5,
+        ).strip()
+        git_source = subprocess.check_output(
+            ["git", "-C", repo, "show", f"{rev}:workspaces/{wid}.yaml"],
+            stderr=subprocess.DEVNULL, timeout=5,
+        )
+    except (OSError, subprocess.SubprocessError):
+        fail("workspace Git revision is unavailable")
+    try:
+        import re
+        from collections import Counter
+        normalize = lambda value: re.findall(r"[A-Za-z0-9_.:/@+-]+", value)
+        git_tokens = Counter(normalize(git_source.decode("utf-8")))
+        snapshot_tokens = Counter(normalize(source.decode("utf-8")))
+        # The registry canonicalizer may add schema defaults/reorder mappings.
+        # Every token from the exact Git descriptor must nevertheless survive;
+        # replacements (including non-rendered workspace.name) are rejected.
+        equivalent = all(snapshot_tokens[k] >= count for k, count in git_tokens.items())
+    except UnicodeDecodeError:
+        equivalent = False
+    if blob != record.get("blob") or not equivalent:
+        fail("workspace Git descriptor identity mismatch")
     return {
         "workspace_id": wid,
         "workspace_revision": rev,