add support for user impersonation for k8s modules (#250)

add support for user impersonation for k8s modules

SUMMARY

k8s module should not allow user to perform operation using impersonation as describe here
https://kubernetes.io/docs/reference/access-authn-authz/authentication/#user-impersonation
This pull request closes #40

ISSUE TYPE


Feature Pull Request

COMPONENT NAME

ADDITIONAL INFORMATION

Reviewed-by: Mike Graves <mgraves@redhat.com>
Reviewed-by: Abhijeet Kasurde <None>
Reviewed-by: None <None>

changelogs/fragments/250-k8s-add-support-for-impersonation.yaml

@@ -0,0 +1,2 @@
+minor_changes:
+  - k8s - add support for user impersonation. (https://github.com/ansible-collections/kubernetes/core/issues/40).

molecule/default/converge.yml

@@ -205,6 +205,14 @@
       tags:
         - always
 
+    - name: Include user_impersonation.yml
+      include_tasks:
+        file: tasks/user_impersonation.yml
+        apply:
+          tags: [ user_impersonation, k8s ]
+      tags:
+        - always
+
   roles:
     - role: helm
       tags:

molecule/default/tasks/user_impersonation.yml

@@ -0,0 +1,211 @@
+- block:
+  - set_fact:
+      test_ns: "impersonate"
+      pod_name: "impersonate-pod"
+      # this use will have authorization to list/create pods in the namespace
+      user_01: "authorized-sa-01"
+      # No authorization attached to this user, will use 'user_01' for impersonation
+      user_02: "unauthorize-sa-01"
+
+  - name: Ensure namespace
+    kubernetes.core.k8s:
+      kind: Namespace
+      name: "{{ test_ns }}"
+
+  - name: Get cluster information
+    kubernetes.core.k8s_cluster_info:
+    register: cluster_info
+    no_log: true
+
+  - set_fact:
+      cluster_host: "{{ cluster_info['connection']['host'] }}"
+
+  - name: Create Service account
+    kubernetes.core.k8s:
+      definition:
+        apiVersion: v1
+        kind: ServiceAccount
+        metadata:
+          name: "{{ item }}"
+          namespace: "{{ test_ns }}"
+    with_items:
+    - "{{ user_01 }}"
+    - "{{ user_02 }}"
+
+  - name: Read Service Account - user_01
+    kubernetes.core.k8s_info:
+      kind: ServiceAccount
+      namespace: "{{ test_ns }}"
+      name: "{{ user_01 }}"
+    register: result
+
+  - name: Get secret details
+    kubernetes.core.k8s_info:
+      kind: Secret
+      namespace: '{{ test_ns }}'
+      name: '{{ result.resources[0].secrets[0].name }}'
+    no_log: true
+    register: _secret
+
+  - set_fact:
+      user_01_api_token: "{{ _secret.resources[0]['data']['token'] | b64decode }}"
+
+  - name: Read Service Account - user_02
+    kubernetes.core.k8s_info:
+      kind: ServiceAccount
+      namespace: "{{ test_ns }}"
+      name: "{{ user_02 }}"
+    register: result
+
+  - name: Get secret details
+    kubernetes.core.k8s_info:
+      kind: Secret
+      namespace: '{{ test_ns }}'
+      name: '{{ result.resources[0].secrets[0].name }}'
+    no_log: true
+    register: _secret
+
+  - set_fact:
+      user_02_api_token: "{{ _secret.resources[0]['data']['token'] | b64decode }}"
+
+  - name: Create Role to manage pod on the namespace
+    kubernetes.core.k8s:
+      namespace: "{{ test_ns }}"
+      definition:
+        apiVersion: rbac.authorization.k8s.io/v1
+        kind: Role
+        metadata:
+          name: pod-manager
+        rules:
+        - apiGroups: [""]
+          resources: ["pods"]
+          verbs: ["create", "get", "delete", "list", "patch"]
+
+  - name: Attach Role to the user_01
+    kubernetes.core.k8s:
+      namespace: "{{ test_ns }}"
+      definition:
+        kind: RoleBinding
+        apiVersion: rbac.authorization.k8s.io/v1
+        metadata:
+          name: pod-manager-binding
+        subjects:
+        - kind: ServiceAccount
+          name: "{{ user_01 }}"
+        roleRef:
+          kind: Role
+          name: pod-manager
+          apiGroup: rbac.authorization.k8s.io
+
+  - name: Create Pod using user_01 credentials
+    kubernetes.core.k8s:
+      api_key: "{{ user_01_api_token }}"
+      host: "{{ cluster_host }}"
+      validate_certs: no
+      namespace: "{{ test_ns }}"
+      name: "{{ pod_name }}"
+      definition:
+        apiVersion: v1
+        kind: Pod
+        metadata:
+          labels:
+            test: "impersonate"
+        spec:
+          containers:
+          - name: c0
+            image: busybox
+            command:
+            - /bin/sh
+            - -c
+            - while true;do date;sleep 5; done
+
+  - name: Delete Pod using user_02 credentials should failed
+    kubernetes.core.k8s:
+      api_key: "{{ user_02_api_token }}"
+      host: "{{ cluster_host }}"
+      validate_certs: no
+      namespace: "{{ test_ns }}"
+      name: "{{ pod_name }}"
+      kind: Pod
+      state: absent
+    register: delete_pod
+    ignore_errors: true
+
+  - name: Assert that operation has failed
+    assert:
+      that:
+      - delete_pod is failed
+      - delete_pod.reason == 'Forbidden'
+
+  - name: Delete Pod using user_02 credentials and impersonation to user_01
+    kubernetes.core.k8s:
+      api_key: "{{ user_02_api_token }}"
+      host: "{{ cluster_host }}"
+      validate_certs: no
+      impersonate_user: "system:serviceaccount:{{ test_ns }}:{{ user_01 }}"
+      namespace: "{{ test_ns }}"
+      name: "{{ pod_name }}"
+      kind: Pod
+      state: absent
+    ignore_errors: true
+    register: delete_pod_2
+
+  - name: Assert that operation has failed
+    assert:
+      that:
+      - delete_pod_2 is failed
+      - delete_pod_2.reason == 'Forbidden'
+      - '"cannot impersonate resource" in delete_pod_2.msg'
+
+  - name: Create Role to impersonate user_01
+    kubernetes.core.k8s:
+      namespace: "{{ test_ns }}"
+      definition:
+        apiVersion: rbac.authorization.k8s.io/v1
+        kind: Role
+        metadata:
+          name: sa-impersonate
+        rules:
+        - apiGroups: [""]
+          resources:
+          - serviceaccounts
+          verbs:
+          - impersonate
+          resourceNames:
+          - "{{ user_01 }}"
+
+  - name: Attach Role to the user_02
+    kubernetes.core.k8s:
+      namespace: "{{ test_ns }}"
+      definition:
+        kind: RoleBinding
+        apiVersion: rbac.authorization.k8s.io/v1
+        metadata:
+          name: sa-impersonate-binding
+        subjects:
+        - kind: ServiceAccount
+          name: "{{ user_02 }}"
+        roleRef:
+          kind: Role
+          name: sa-impersonate
+          apiGroup: rbac.authorization.k8s.io
+
+  - name: Delete Pod using user_02 credentials should succeed now
+    kubernetes.core.k8s:
+      api_key: "{{ user_02_api_token }}"
+      host: "{{ cluster_host }}"
+      validate_certs: no
+      impersonate_user: "system:serviceaccount:{{ test_ns }}:{{ user_01 }}"
+      namespace: "{{ test_ns }}"
+      name: "{{ pod_name }}"
+      kind: Pod
+      state: absent
+
+  always:
+  - name: Ensure namespace is deleted
+    kubernetes.core.k8s:
+      state: absent
+      kind: Namespace
+      name: "{{ test_ns }}"
+      wait: yes
+    ignore_errors: true

plugins/doc_fragments/k8s_auth_options.py

@@ -119,6 +119,19 @@ options:
     - Please note that the current version of the k8s python client library does not support setting this flag to True yet.
     - "The fix for this k8s python library is here: https://github.com/kubernetes-client/python-base/pull/169"
     type: bool
+  impersonate_user:
+    description:
+    - Username to impersonate for the operation.
+    - Can also be specified via K8S_AUTH_IMPERSONATE_USER environment.
+    type: str
+    version_added: 2.3.0
+  impersonate_groups:
+    description:
+    - Group(s) to impersonate for the operation.
+    - "Can also be specified via K8S_AUTH_IMPERSONATE_GROUPS environment. Example: 'Group1,Group2'"
+    type: list
+    elements: str
+    version_added: 2.3.0
 notes:
   - "To avoid SSL certificate validation errors when C(validate_certs) is I(True), the full
     certificate chain for the API server must be provided via C(ca_cert) or in the

plugins/module_utils/args_common.py

@@ -32,6 +32,8 @@ AUTH_ARG_SPEC = {
     "no_proxy": {"type": "str"},
     "proxy_headers": {"type": "dict", "options": AUTH_PROXY_HEADERS_SPEC},
     "persist_config": {"type": "bool"},
+    "impersonate_user": {},
+    "impersonate_groups": {"type": "list", "elements": "str"},
 }
 
 WAIT_ARG_SPEC = dict(

plugins/module_utils/common.py

@@ -127,7 +127,7 @@ except ImportError as e:
     K8S_IMP_ERR = traceback.format_exc()
 
 
-def configuration_digest(configuration):
+def configuration_digest(configuration, **kwargs):
     m = hashlib.sha256()
     for k in AUTH_ARG_MAP:
         if not hasattr(configuration, k):
@@ -140,10 +140,32 @@ def configuration_digest(configuration):
                 m.update(content.encode())
         else:
             m.update(str(v).encode())
+    for k in kwargs:
+        content = "{0}: {1}".format(k, kwargs.get(k))
+        m.update(content.encode())
     digest = m.hexdigest()
     return digest
 
 
+class unique_string(str):
+    _low = None
+
+    def __hash__(self):
+        return id(self)
+
+    def __eq__(self, other):
+        return self is other
+
+    def lower(self):
+        if self._low is None:
+            lower = str.lower(self)
+            if str.__eq__(lower, self):
+                self._low = self
+            else:
+                self._low = unique_string(lower)
+        return self._low
+
+
 def get_api_client(module=None, **kwargs):
     auth = {}
 
@@ -219,9 +241,14 @@ def get_api_client(module=None, **kwargs):
                 "Failed to set no_proxy due to: %s",
             )
 
+    configuration = None
     if auth_set("username", "password", "host") or auth_set("api_key", "host"):
         # We have enough in the parameters to authenticate, no need to load incluster or kubeconfig
-        pass
+        arg_init = {}
+        # api_key will be set later in this function
+        for key in ("username", "password", "host"):
+            arg_init[key] = auth.get(key)
+        configuration = kubernetes.client.Configuration(**arg_init)
     elif auth_set("kubeconfig") or auth_set("context"):
         try:
             _load_config()
@@ -240,10 +267,11 @@ def get_api_client(module=None, **kwargs):
 
     # Override any values in the default configuration with Ansible parameters
     # As of kubernetes-client v12.0.0, get_default_copy() is required here
-    try:
-        configuration = kubernetes.client.Configuration().get_default_copy()
-    except AttributeError:
-        configuration = kubernetes.client.Configuration()
+    if not configuration:
+        try:
+            configuration = kubernetes.client.Configuration().get_default_copy()
+        except AttributeError:
+            configuration = kubernetes.client.Configuration()
 
     for key, value in iteritems(auth):
         if key in AUTH_ARG_MAP.keys() and value is not None:
@@ -257,14 +285,46 @@ def get_api_client(module=None, **kwargs):
             else:
                 setattr(configuration, key, value)
 
-    digest = configuration_digest(configuration)
+    api_client = kubernetes.client.ApiClient(configuration)
+    impersonate_map = {
+        "impersonate_user": "Impersonate-User",
+        "impersonate_groups": "Impersonate-Group",
+    }
+    api_digest = {}
+
+    headers = {}
+    for arg_name, header_name in impersonate_map.items():
+        value = None
+        if module and module.params.get(arg_name) is not None:
+            value = module.params.get(arg_name)
+        elif arg_name in kwargs and kwargs.get(arg_name) is not None:
+            value = kwargs.get(arg_name)
+        else:
+            value = os.getenv("K8S_AUTH_{0}".format(arg_name.upper()), None)
+            if value is not None:
+                if AUTH_ARG_SPEC[arg_name].get("type") == "list":
+                    value = [x for x in env_value.split(",") if x != ""]
+        if value:
+            if isinstance(value, list):
+                api_digest[header_name] = ",".join(sorted(value))
+                for v in value:
+                    api_client.set_default_header(
+                        header_name=unique_string(header_name), header_value=v
+                    )
+            else:
+                api_digest[header_name] = value
+                api_client.set_default_header(
+                    header_name=header_name, header_value=value
+                )
+
+    digest = configuration_digest(configuration, **api_digest)
     if digest in get_api_client._pool:
         client = get_api_client._pool[digest]
         return client
 
     try:
         client = k8sdynamicclient.K8SDynamicClient(
-            kubernetes.client.ApiClient(configuration), discoverer=LazyDiscoverer
+            api_client, discoverer=LazyDiscoverer
         )
     except Exception as err:
         _raise_or_fail(err, "Failed to get client due to %s")