ruby: add MaD model for permissions needed by actions

Use this to suggest minimal set of nedded permissions

Author: yoff

actions/ql/lib/codeql/actions/Ast.qll

@@ -242,6 +242,8 @@ class Step extends AstNode instanceof StepImpl {
 
   If getIf() { result = super.getIf() }
 
+  AstNode getUses() { result = super.getUses() }
+
   StepsContainer getContainer() { result = super.getContainer() }
 
   Step getNextStep() { result = super.getNextStep() }

actions/ql/lib/codeql/actions/ast/internal/Ast.qll

@@ -1194,6 +1194,8 @@ class StepImpl extends AstNodeImpl, TStepNode {
   /** Gets the value of the `if` field in this step, if any. */
   IfImpl getIf() { result.getNode() = n.lookup("if") }
 
+  AstNodeImpl getUses() { result.getNode() = n.lookup("uses") }
+
   /** Gets the Runs or LocalJob that this step is in. */
   StepsContainerImpl getContainer() {
     result = this.getParentNode().(RunsImpl) or

actions/ql/lib/codeql/actions/config/Config.qll

@@ -154,3 +154,13 @@ predicate untrustedGitCommandDataModel(string cmd_regex, string flag) {
 predicate untrustedGhCommandDataModel(string cmd_regex, string flag) {
   Extensions::untrustedGhCommandDataModel(cmd_regex, flag)
 }
+
+/**
+ * MaD models for permissions needed by actions
+ * Fields:
+ *    - action: action name
+ *    - permission: permission name
+ */
+predicate actionsPermissionsDataModel(string action, string permission) {
+  Extensions::actionsPermissionsDataModel(action, permission)
+}

actions/ql/lib/codeql/actions/config/ConfigExtensions.qll

@@ -77,3 +77,8 @@ extensible predicate untrustedGitCommandDataModel(string cmd_regex, string flag)
  * Holds for gh commands that may introduce untrusted data
  */
 extensible predicate untrustedGhCommandDataModel(string cmd_regex, string flag);
+
+/**
+ * Holds if `action` needs `permission` to run.
+ */
+extensible predicate actionsPermissionsDataModel(string action, string permission);

actions/ql/lib/ext/config/actions_permissions.yml

@@ -0,0 +1,37 @@
+extensions:
+  - addsTo:
+      pack: codeql/actions-all
+      extensible: actionsPermissionsDataModel
+    data:
+      - ["actions/checkout", "contents: read"]
+      - ["actions/setup-node", "contents: read"]
+      - ["actions/setup-python", "contents: read"]
+      - ["actions/setup-java", "contents: read"]
+      - ["actions/setup-go", "contents: read"]
+      - ["actions/setup-dotnet", "contents: read"]
+      - ["actions/labeler", "contents: read"]
+      - ["actions/labeler", "pull-requests: write"]
+      - ["actions/attest", "id-token: write"]
+      - ["actions/attest", "attestations: write"]
+      # No permissions needed for actions/add-to-project
+      - ["actions/dependency-review-action", "contents: read"]
+      - ["actions/attest-sbom", "id-token: write"]
+      - ["actions/attest-sbom", "attestations: write"]
+      - ["actions/stale", "contents: write"]
+      - ["actions/stale", "issues: write"]
+      - ["actions/stale", "pull-requests: write"]
+      - ["actions/attest-build-provenance", "id-token: write"]
+      - ["actions/attest-build-provenance", "attestations: write"]
+      - ["actions/jekyll-build-pages", "contents: read"]
+      - ["actions/jekyll-build-pages", "pages: write"]
+      - ["actions/jekyll-build-pages", "id-token: write"]
+      - ["actions/publish-action", "contents: write"]
+      - ["actions/versions-package-tools", "contents: read"]      
+      - ["actions/versions-package-tools", "actions: read"]
+      - ["actions/reusable-workflows", "contents: read"]      
+      - ["actions/reusable-workflows", "actions: read"]
+      # TODO: Add permissions for actions/download-artifact
+      # TODO: Add permissions for actions/upload-artifact
+      # TODO: Add permissions for actions/cache
+
+      

actions/ql/src/Security/CWE-275/MissingActionsPermissions.ql

@@ -14,13 +14,36 @@
 
 import actions
 
-from Job job
+Step stepInJob(Job job) { result = job.(LocalJob).getAStep() }
+
+bindingset[fullActionSelector]
+string versionedAction(string fullActionSelector) {
+  result = fullActionSelector.substring(0, fullActionSelector.indexOf("@"))
+  or
+  not exists(fullActionSelector.indexOf("@")) and
+  result = fullActionSelector
+}
+
+string stepUses(Step step) { result = step.getUses().(ScalarValue).getValue() }
+
+string jobNeedsPersmission(Job job) {
+  actionsPermissionsDataModel(versionedAction(stepUses(stepInJob(job))), result)
+}
+
+string permissionsForJob(Job job) {
+  result =
+    "{" + concat(string permission | permission = jobNeedsPersmission(job) | permission, ", ") + "}"
+}
+
+from Job job, string permissions
 where
   not exists(job.getPermissions()) and
   not exists(job.getEnclosingWorkflow().getPermissions()) and
   // exists a trigger event that is not a workflow_call
   exists(Event e |
     e = job.getATriggerEvent() and
     not e.getName() = "workflow_call"
-  )
-select job, "Actions Job or Workflow does not set permissions"
+  ) and
+  permissions = permissionsForJob(job)
+select job,
+  "Actions Job or Workflow does not set permissions. A minimal set might be " + permissions

actions/ql/test/query-tests/Security/CWE-275/.github/workflows/perms6.yml

@@ -0,0 +1,13 @@
+on:
+  workflow_call:
+  workflow_dispatch:
+
+jobs:
+  build:
+    name: Build and test
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/jekyll-build-pages
+
+

actions/ql/test/query-tests/Security/CWE-275/MissingActionsPermissions.expected

@@ -1,3 +1,4 @@
-| .github/workflows/perms1.yml:6:5:9:32 | Job: build | Actions Job or Workflow does not set permissions |
-| .github/workflows/perms2.yml:6:5:10:2 | Job: build | Actions Job or Workflow does not set permissions |
-| .github/workflows/perms5.yml:7:5:10:32 | Job: build | Actions Job or Workflow does not set permissions |
+| .github/workflows/perms1.yml:6:5:9:32 | Job: build | Actions Job or Workflow does not set permissions. A minimal set might be {contents: read} |
+| .github/workflows/perms2.yml:6:5:10:2 | Job: build | Actions Job or Workflow does not set permissions. A minimal set might be {contents: read} |
+| .github/workflows/perms5.yml:7:5:10:32 | Job: build | Actions Job or Workflow does not set permissions. A minimal set might be {contents: read} |
+| .github/workflows/perms6.yml:7:5:11:39 | Job: build | Actions Job or Workflow does not set permissions. A minimal set might be {contents: read, id-token: write, pages: write} |