Support for Pipeline As Code Tekton (#174)

* parse pipeline as code tekton
* untrusted checkout pipeline as code tekton
* added injection detection for script steps

models/package_insights.go

@@ -31,6 +31,7 @@ type PackageInsights struct {
 	GithubActionsMetadata  []GithubActionsMetadata `json:"github_actions_metadata"`
 	GitlabciConfigs        []GitlabciConfig        `json:"gitlabci_configs"`
 	AzurePipelines         []AzurePipeline         `json:"azure_pipelines"`
+	PipelineAsCodeTekton   []PipelineAsCodeTekton  `json:"pipeline_as_code_tekton"`
 }
 
 func (p *PackageInsights) GetSourceGitRepoURI() string {

models/pipeline_as_code_tekton.go

@@ -0,0 +1,61 @@
+package models
+
+import "gopkg.in/yaml.v3"
+
+type PipelineAsCodeTekton struct {
+	ApiVersion string `json:"api_version" yaml:"apiVersion"`
+	Kind       string `json:"kind"`
+	Metadata   struct {
+		Name        string            `json:"name"`
+		Annotations map[string]string `json:"annotations"`
+	} `json:"metadata"`
+	Spec PipelineRunSpec `json:"spec,omitempty" yaml:"spec"`
+
+	Path string `json:"path" yaml:"-"`
+}
+
+type PipelineRunSpec struct {
+	PipelineSpec *PipelineSpec `json:"pipeline_spec,omitempty" yaml:"pipelineSpec"`
+}
+
+type PipelineSpec struct {
+	Tasks []PipelineTask `json:"tasks,omitempty" yaml:"tasks"`
+}
+
+type PipelineTask struct {
+	Name string `json:"name,omitempty"`
+
+	TaskSpec *TaskSpec `json:"task_spec,omitempty" yaml:"taskSpec"`
+}
+
+type TaskSpec struct {
+	Steps []Step `json:"steps,omitempty"`
+}
+
+type Step struct {
+	Name   string         `json:"name"`
+	Script string         `json:"script,omitempty"`
+	Lines  map[string]int `json:"lines" yaml:"-"`
+}
+
+func (o *Step) UnmarshalYAML(node *yaml.Node) error {
+	type step Step
+	var s step
+	if err := node.Decode(&s); err != nil {
+		return err
+	}
+
+	if node.Kind == yaml.MappingNode {
+		s.Lines = map[string]int{"start": node.Line}
+		for i := 0; i < len(node.Content); i += 2 {
+			key := node.Content[i].Value
+			switch key {
+			case "script":
+				s.Lines[key] = node.Content[i+1].Line
+			}
+		}
+	}
+
+	*o = Step(s)
+	return nil
+}

opa/rego/rules/injection.rego

@@ -101,3 +101,31 @@ results contains poutine.finding(rule, pkg.purl, {
 	exprs := azure_injections(step[attr])
 	count(exprs) > 0
 }
+
+patterns.pipeline_as_code_tekton contains "\\{\\{\\s*(body\\.pull_request\\.(title|user\\.email|body)|source_branch)\\s*\\}\\}"
+
+pipeline_as_code_tekton_injections(str) = {expr |
+	match := regex.find_n(patterns.pipeline_as_code_tekton[_], str, -1)[_]
+	expr := regex.find_all_string_submatch_n("\\{\\{\\s*([^}]+?)\\s*\\}\\}", match, 1)[0][1]
+}
+
+results contains poutine.finding(rule, pkg.purl, {
+	"path": pipeline.path,
+	"job": task.name,
+	"step": step_idx,
+	"line": step.lines["start"],
+	"details": sprintf("Sources: %s", [concat(" ", exprs)]),
+}) if {
+    pkg := input.packages[_]
+    pipeline := pkg.pipeline_as_code_tekton[_]
+    contains(pipeline.api_version, "tekton.dev")
+    pipeline.kind == "PipelineRun"
+    contains(pipeline.metadata.annotations["pipelinesascode.tekton.dev/on-event"], "pull_request")
+    task := pipeline.spec.pipeline_spec.tasks[_]
+    step := task.task_spec.steps[step_idx]
+
+    exprs := pipeline_as_code_tekton_injections(step.script)
+    count(exprs) > 0
+}
+
+

opa/rego/rules/untrusted_checkout_exec.rego

@@ -44,6 +44,7 @@ build_commands[cmd] = {
 	"bundler": {"bundle install", "bundle exec "},
 	"ant": {"^ant "},
 	"mkdocs": {"mkdocs build"},
+	"vale": {"vale "},
 }[cmd]
 
 results contains poutine.finding(rule, pkg_purl, {
@@ -134,3 +135,26 @@ find_ado_checkout(stage) := xs if {
 		s[step_attr] == "self"
 	}
 }
+
+# Pipeline As Code Tekton
+
+results contains poutine.finding(rule, pkg.purl, {
+	"path": pipeline.path,
+	"job": task.name,
+	"step": step_idx,
+	"line": step.lines["script"],
+	"details": sprintf("Detected usage of `%s`", [cmd]),
+}) if {
+    pkg := input.packages[_]
+    pipeline := pkg.pipeline_as_code_tekton[_]
+    contains(pipeline.api_version, "tekton.dev")
+    pipeline.kind == "PipelineRun"
+    contains(pipeline.metadata.annotations["pipelinesascode.tekton.dev/on-event"], "pull_request")
+    contains(pipeline.metadata.annotations["pipelinesascode.tekton.dev/task"], "git-clone")
+    task := pipeline.spec.pipeline_spec.tasks[_]
+    step := task.task_spec.steps[step_idx]
+	regex.match(
+		sprintf("([^a-z]|^)(%v)", [concat("|", build_commands[cmd])]),
+		step.script,
+	)
+}

scanner/inventory_test.go

@@ -397,6 +397,28 @@ func TestFindings(t *testing.T) {
 				Details: "Detected usage of `npm`",
 			},
 		},
+		{
+			RuleId: "untrusted_checkout_exec",
+			Purl:   purl,
+			Meta: opa.FindingMeta{
+				Path:    ".tekton/pipeline-as-code-tekton.yml",
+				Line:    43,
+				Job:     "vale",
+				Step:    "0",
+				Details: "Detected usage of `vale`",
+			},
+		},
+		{
+			RuleId: "injection",
+			Purl:   purl,
+			Meta: opa.FindingMeta{
+				Path:    ".tekton/pipeline-as-code-tekton.yml",
+				Line:    45,
+				Job:     "vale",
+				Step:    "1",
+				Details: "Sources: body.pull_request.body",
+			},
+		},
 	}
 
 	assert.Equal(t, len(findings), len(results.Findings))

scanner/scanner.go

@@ -154,6 +154,30 @@ func parseGitlabCi(scanner *Scanner, filePath string, fileInfo fs.FileInfo) erro
 	return nil
 }
 
+func parsePipelineAsCodeTekton(scanner *Scanner, filePath string, fileInfo fs.FileInfo) error {
+	relPath, err := filepath.Rel(scanner.Path, filePath)
+	if err != nil {
+		return err
+	}
+
+	data, err := os.ReadFile(filePath)
+	if err != nil {
+		return err
+	}
+
+	pipelineAsCode := models.PipelineAsCodeTekton{}
+	err = yaml.Unmarshal(data, &pipelineAsCode)
+	if err != nil {
+		log.Debug().Err(err).Str("file", relPath).Msg("failed to unmarshal pipeline as code yaml file")
+		return nil
+	}
+
+	pipelineAsCode.Path = relPath
+	scanner.Package.PipelineAsCodeTekton = append(scanner.Package.PipelineAsCodeTekton, pipelineAsCode)
+
+	return nil
+}
+
 type Scanner struct {
 	Path          string
 	Package       *models.PackageInsights
@@ -169,6 +193,7 @@ func NewScanner(path string) Scanner {
 		ParseFuncs: map[*regexp.Regexp]parseFunc{
 			regexp.MustCompile(`(\b|/)action\.ya?ml$`):              parseGithubActionsMetadata,
 			regexp.MustCompile(`^\.github/workflows/[^/]+\.ya?ml$`): parseGithubWorkflows,
+			regexp.MustCompile(`^\.tekton/[^/]+\.ya?ml$`):           parsePipelineAsCodeTekton,
 			regexp.MustCompile(`\.?azure-pipelines(-.+)?\.ya?ml$`):  parseAzurePipelines,
 			regexp.MustCompile(`\.?gitlab-ci(-.+)?\.ya?ml$`):        parseGitlabCi,
 		},

scanner/scanner_test.go

@@ -2,6 +2,7 @@ package scanner
 
 import (
 	"context"
+	"github.com/boostsecurityio/poutine/models"
 	"github.com/boostsecurityio/poutine/opa"
 	"github.com/stretchr/testify/assert"
 	"testing"
@@ -69,3 +70,53 @@ func TestRun(t *testing.T) {
 	assert.Contains(t, s.Package.PackageDependencies, "pkg:docker/alpine%3Alatest")
 	assert.Equal(t, 3, len(s.Package.GitlabciConfigs))
 }
+
+func TestPipelineAsCodeTekton(t *testing.T) {
+	s := NewScanner("testdata")
+	o, _ := opa.NewOpa()
+	err := s.Run(context.TODO(), o)
+	assert.NoError(t, err)
+
+	pipelines := s.Package.PipelineAsCodeTekton
+
+	assert.Len(t, pipelines, 1)
+	expectedAnnotations := map[string]string{
+		"pipelinesascode.tekton.dev/on-event":         "[push, pull_request]",
+		"pipelinesascode.tekton.dev/on-target-branch": "[*]",
+		"pipelinesascode.tekton.dev/task":             "[git-clone]",
+	}
+	expectedPipeline := models.PipelineAsCodeTekton{
+		ApiVersion: "tekton.dev/v1beta1",
+		Kind:       "PipelineRun",
+		Metadata: struct {
+			Name        string            `json:"name"`
+			Annotations map[string]string `json:"annotations"`
+		}{
+			Name:        "linters",
+			Annotations: expectedAnnotations,
+		},
+		Spec: models.PipelineRunSpec{
+			PipelineSpec: &models.PipelineSpec{
+				Tasks: []models.PipelineTask{
+					{
+						Name: "fetchit",
+					},
+					{
+						Name: "vale",
+						TaskSpec: &models.TaskSpec{
+							Steps: []models.Step{
+								{
+									Name:   "vale-lint",
+									Script: "vale docs/content --minAlertLevel=error --output=line\n",
+									Lines:  map[string]int{"script": 43, "start": 40},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	assert.Equal(t, expectedPipeline.Metadata, pipelines[0].Metadata)
+	assert.Equal(t, expectedPipeline.Spec.PipelineSpec.Tasks[1].TaskSpec.Steps[0], pipelines[0].Spec.PipelineSpec.Tasks[1].TaskSpec.Steps[0])
+}

scanner/testdata/.tekton/pipeline-as-code-tekton.yml

@@ -0,0 +1,63 @@
+apiVersion: tekton.dev/v1beta1
+kind: PipelineRun
+metadata:
+  name: linters
+  annotations:
+    pipelinesascode.tekton.dev/on-event: "[push, pull_request]"
+    pipelinesascode.tekton.dev/on-target-branch: "[*]"
+    pipelinesascode.tekton.dev/task: "[git-clone]"
+spec:
+  params:
+    - name: repo_url
+      value: "{{repo_url}}"
+    - name: revision
+      value: "{{revision}}"
+  pipelineSpec:
+    params:
+      - name: repo_url
+      - name: revision
+    tasks:
+      - name: fetchit
+        displayName: "Fetch git repository"
+        params:
+          - name: url
+            value: $(params.repo_url)
+          - name: revision
+            value: $(params.revision)
+        taskRef:
+          name: git-clone
+        workspaces:
+          - name: output
+            workspace: source
+      - name: vale
+        displayName: "Spelling and Grammar"
+        runAfter:
+          - fetchit
+        taskSpec:
+          workspaces:
+            - name: source
+          steps:
+            - name: vale-lint
+              image: jdkato/vale
+              workingDir: $(workspaces.source.path)
+              script: |
+                vale docs/content --minAlertLevel=error --output=line
+            - name: injection
+              image: jdkato/vale
+              workingDir: $(workspaces.source.path)
+              script: |
+                binary {{body.pull_request.body}}
+        workspaces:
+          - name: source
+            workspace: source
+    workspaces:
+      - name: source
+  workspaces:
+    - name: source
+      volumeClaimTemplate:
+        spec:
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 5Gi