Harden pwnshop challenge validation and runtimes

Author: zardus

runtime/platform/default.nix

@@ -15,6 +15,24 @@ let
 
   docker = pkgs.docker;
 
+  kataShim = pkgs.writeShellApplication {
+    name = "containerd-shim-kata-v2";
+    text = ''
+      last_arg=
+      for arg in "$@"; do
+        last_arg="$arg"
+      done
+
+      # Kata's standalone cleanup helper otherwise detects this
+      # user-namespaced process as rootless and looks below /run/user/0.
+      if [[ "$last_arg" == "delete" ]]; then
+        export XDG_RUNTIME_DIR=/
+      fi
+
+      exec ${pkgs.kata-runtime}/bin/containerd-shim-kata-v2 "$@"
+    '';
+  };
+
   jsonFormat = pkgs.formats.json { };
 
   kataKernel = import ./kernel.nix { inherit pkgs name; };
@@ -54,7 +72,10 @@ let
         substituteInPlace "$out" \
           --replace-fail \
             "$annotations_line" \
-            'enable_annotations = ["enable_iommu", "virtio_fs_extra_args", "kernel_params", "kernel_verity_params", "default_memory"]'
+            'enable_annotations = ["enable_iommu", "virtio_fs_extra_args", "kernel_params", "kernel_verity_params", "default_memory"]' \
+          --replace-fail \
+            'sandbox_cgroup_only = false' \
+            'sandbox_cgroup_only = true'
       '';
 
   dockerDaemonJson = jsonFormat.generate "${name}-docker-daemon.json" {
@@ -72,7 +93,7 @@ let
 
     "runtimes" = {
       "kata" = {
-        "runtimeType" = "${pkgs.kata-runtime}/bin/containerd-shim-kata-v2";
+        "runtimeType" = "${kataShim}/bin/containerd-shim-kata-v2";
         "options" = {
           "ConfigPath" = "${kataConfigToml}";
         };
@@ -159,9 +180,13 @@ pkgs.writeShellApplication {
     docker_service_unit="${name}-docker.service"
     containerd_service_unit="${name}-containerd.service"
 
+    current_socket_link="$(readlink -f "/run/systemd/system/$docker_socket_unit" 2>/dev/null || true)"
     current_service_link="$(readlink -f "/run/systemd/system/$docker_service_unit" 2>/dev/null || true)"
+    current_containerd_link="$(readlink -f "/run/systemd/system/$containerd_service_unit" 2>/dev/null || true)"
 
-    if [[ "$current_service_link" == "${dockerSystemdServiceUnit}" ]] \
+    if [[ "$current_socket_link" == "${dockerSystemdSocketUnit}" ]] \
+      && [[ "$current_service_link" == "${dockerSystemdServiceUnit}" ]] \
+      && [[ "$current_containerd_link" == "${containerdServiceUnit}" ]] \
       && DOCKER_HOST="$docker_host" docker info >/dev/null 2>&1; then
       emit_environment
       exit 0

runtime/platform/kernel.nix

@@ -33,8 +33,12 @@ let
         "FUNCTION_TRACER"
         "KPROBE_EVENTS"
         "KPROBES"
+        "KVM"
+        "KVM_AMD"
+        "KVM_INTEL"
         "PERF_EVENTS"
         "PROFILING"
+        "VIRTUALIZATION"
       ];
     in
     pkgs.writeText "${name}.conf" (pkgs.lib.strings.concatLines (map (t: "CONFIG_${t}=y") enable));

runtime/workspace/agent/cmd/workspace-entrypoint/main.go

@@ -26,6 +26,8 @@ const workspaceProfileBin = "/run/workspace/profile/bin"
 const workspaceProfileScript = "/run/workspace/profile/etc/profile.d/99-pwn-workspace.sh"
 const workspaceUserRunDir = "/run/workspace/user"
 const workspaceServicesDir = "/run/workspace/user/services"
+const legacyDojoWorkspaceDir = "/run/dojo/sys/workspace"
+const legacyDojoPrivilegedFile = "/run/dojo/sys/workspace/privileged"
 const systemProfileScript = "/etc/profile.d/99-pwn-workspace.sh"
 const userShell = "/run/workspace/profile/bin/bash"
 
@@ -141,6 +143,9 @@ func prepareWorkspace(config workspaceConfig) error {
 	if err := setupRunDirectories(); err != nil {
 		return err
 	}
+	if err := setupLegacyDojoWorkspace(); err != nil {
+		return err
+	}
 	if err := setupSystemEnvironment(); err != nil {
 		return err
 	}
@@ -182,6 +187,20 @@ func setupRunDirectories() error {
 	return linkServiceDefinitions()
 }
 
+func setupLegacyDojoWorkspace() error {
+	privileged := "0\n"
+	if os.Getenv("PWN_WORKSPACE_PRIVILEGED") == "1" {
+		privileged = "1\n"
+	}
+	if err := os.MkdirAll(legacyDojoWorkspaceDir, 0755); err != nil {
+		return err
+	}
+	if err := os.WriteFile(legacyDojoPrivilegedFile, []byte(privileged), 0644); err != nil {
+		return err
+	}
+	return os.Chmod(legacyDojoPrivilegedFile, 0644)
+}
+
 func linkChallengeBin() error {
 	if _, err := os.Stat(challengeBin); errors.Is(err, os.ErrNotExist) {
 		return nil

runtime/workspace/packages/default.nix

@@ -6,6 +6,7 @@ let
       pexpect
       pwntools
       pycryptodome
+      pycryptodomex
       requests
       scapy
     ]

runtime/workspace/packages/extended.nix

@@ -19,6 +19,7 @@ let
       psutil
       pwntools
       pycryptodome
+      pycryptodomex
       pyroute2
       r2pipe
       requests

tools/dojo/parse-dojo-yml

@@ -22,6 +22,7 @@ from pydantic import BaseModel, ConfigDict, Field, ValidationError, field_valida
 ID_REGEX = re.compile(r"^[a-z0-9-]{1,32}$")
 
 INHERIT_KEYS = ["privileged", "interfaces"]
+LOCAL_CHALLENGE_CONFIG_KEYS = {"allow_unsupported_tests"}
 
 
 class Visibility(BaseModel):
@@ -278,6 +279,11 @@ def main() -> int:
                     if resource.get("type") == "challenge":
                         challenge_id = resource.get("id")
                         challenge_data, challenge_description_md = challenge_reads.get(challenge_id, ({}, None))
+                        challenge_data = {
+                            key: value
+                            for key, value in challenge_data.items()
+                            if key not in LOCAL_CHALLENGE_CONFIG_KEYS
+                        }
 
                         resource = {**challenge_data, **resource, "type": "challenge", "id": challenge_id}
                         resource.setdefault(
@@ -300,6 +306,11 @@ def main() -> int:
 
                     challenge_id = challenge.get("id")
                     challenge_data, challenge_description_md = challenge_reads.get(challenge_id, ({}, None))
+                    challenge_data = {
+                        key: value
+                        for key, value in challenge_data.items()
+                        if key not in LOCAL_CHALLENGE_CONFIG_KEYS
+                    }
 
                     resource = {**challenge_data, **challenge, "type": "challenge", "id": challenge_id}
                     resource.setdefault(