feat: Govulncheck source call analysis enricher

LICENSE

@@ -203,6 +203,7 @@
 
 ------------------
 File: extractor/filesystem/internal/walkdir_iterate.go
+File: enricher/govulncheck/source/internal/result.go
 ------------------
 
 Copyright 2009, Google Inc.

enricher/enricher.go

@@ -38,6 +38,7 @@ var (
 	EnricherOrder = []string{
 		"reachability/java",
 		"vulnmatch/osvdev",
+		"reachability/govcsource",
 		"vex/filter",
 	}
 )

enricher/enricherlist/list.go

@@ -23,6 +23,7 @@ import (
 	cpb "github.com/google/osv-scalibr/binary/proto/config_go_proto"
 	"github.com/google/osv-scalibr/enricher"
 	"github.com/google/osv-scalibr/enricher/baseimage"
+	govcsource "github.com/google/osv-scalibr/enricher/govulncheck/source"
 	"github.com/google/osv-scalibr/enricher/hcpidentity"
 	"github.com/google/osv-scalibr/enricher/huggingfacemeta"
 	"github.com/google/osv-scalibr/enricher/license"
@@ -130,7 +131,8 @@ var (
 
 	// Reachability enrichers.
 	Reachability = InitMap{
-		java.Name: {noCFG(java.NewDefault)},
+		java.Name:       {noCFG(java.NewDefault)},
+		govcsource.Name: {govcsource.New},
 	}
 
 	// TransitiveDependency enrichers.

enricher/govulncheck/source/govulncheck.go

@@ -0,0 +1,245 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package source provides an enricher that uses govulncheck to scan Go source code.
+package source
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"slices"
+
+	cpb "github.com/google/osv-scalibr/binary/proto/config_go_proto"
+	"github.com/google/osv-scalibr/enricher/govulncheck/source/internal"
+	"github.com/google/osv-scalibr/extractor"
+	"github.com/ossf/osv-schema/bindings/go/osvschema"
+
+	"github.com/google/osv-scalibr/enricher"
+	"github.com/google/osv-scalibr/extractor/filesystem/language/golang/gomod"
+	"github.com/google/osv-scalibr/inventory"
+	"github.com/google/osv-scalibr/inventory/vex"
+	"github.com/google/osv-scalibr/log"
+	"github.com/google/osv-scalibr/plugin"
+	"golang.org/x/vuln/scan"
+)
+
+const (
+	// Name is the unique name of this enricher.
+	Name = "reachability/govcsource"
+)
+
+// ErrNoGoToolchain is returned when the go toolchain is not found in the system.
+var ErrNoGoToolchain = errors.New("no Go toolchain found")
+
+// Enricher is an enricher that runs govulncheck on Go source code.
+type Enricher struct {
+	offlineVulnDBPath string
+}
+
+// Name returns the name of the enricher.
+func (e *Enricher) Name() string {
+	return Name
+}
+
+// Version returns the version of the enricher.
+func (e *Enricher) Version() int {
+	return 0
+}
+
+// Requirements returns the requirements of the enricher.
+func (e *Enricher) Requirements() *plugin.Capabilities {
+	var network plugin.Network
+	if e.offlineVulnDBPath != "" {
+		network = plugin.NetworkOffline
+	} else {
+		network = plugin.NetworkOnline
+	}
+
+	return &plugin.Capabilities{
+		Network:       network,
+		DirectFS:      true,
+		RunningSystem: true,
+	}
+}
+
+// RequiredPlugins returns the names of the plugins required by this enricher.
+func (e *Enricher) RequiredPlugins() []string {
+	return []string{gomod.Name}
+}
+
+// Enrich runs govulncheck on the Go modules in the inventory.
+func (e *Enricher) Enrich(ctx context.Context, input *enricher.ScanInput, inv *inventory.Inventory) error {
+	cmd := exec.CommandContext(ctx, "go", "version")
+	_, err := cmd.Output()
+	if err != nil {
+		return ErrNoGoToolchain
+	}
+
+	goModVersions := make(map[string]string)
+	for _, pkg := range inv.Packages {
+		if !slices.Contains(pkg.Plugins, gomod.Name) {
+			continue
+		}
+		if pkg.Name == "stdlib" {
+			for _, l := range pkg.Locations {
+				if goModVersions[l] != "" {
+					continue
+				}
+
+				// Set GOVERSION to the Go version in go.mod.
+				goModVersions[l] = pkg.Version
+
+				continue
+			}
+		}
+	}
+
+	for goModLocation, goVersion := range goModVersions {
+		modDir := filepath.Dir(goModLocation)
+		absModDir := filepath.Join(input.ScanRoot.Path, modDir)
+		findings, err := e.runGovulncheck(ctx, absModDir, goVersion)
+		if err != nil {
+			log.Errorf("govulncheck on %s: %v", modDir, err)
+			continue
+		}
+
+		if len(findings) == 0 {
+			continue
+		}
+
+		e.addSignals(inv, findings)
+	}
+
+	return nil
+}
+
+func (e *Enricher) addSignals(inv *inventory.Inventory, idToFindings map[string][]*internal.Finding) {
+	for _, pv := range inv.PackageVulns {
+		findings, exist := idToFindings[pv.Vulnerability.Id]
+
+		if !exist {
+			if vulnHasImportsField(pv.Vulnerability, pv.Package) {
+				// If there is symbol information, then analysis has been performed, and
+				// code does not import the vulnerable package, so definitely not called
+				pv.ExploitabilitySignals = append(pv.ExploitabilitySignals, &vex.FindingExploitabilitySignal{
+					Plugin:        Name,
+					Justification: vex.VulnerableCodeNotInExecutePath,
+				})
+			}
+
+			// Otherwise, we don't know if the code is reachable or not.
+			continue
+		}
+
+		// For entries with findings, check if the code is reachable or not by whether there is a trace.
+		isReachable := false
+		for _, f := range findings {
+			if len(f.Trace) > 0 && f.Trace[0].Function != "" {
+				isReachable = true
+				break
+			}
+		}
+
+		if !isReachable {
+			pv.ExploitabilitySignals = append(pv.ExploitabilitySignals, &vex.FindingExploitabilitySignal{
+				Plugin:        Name,
+				Justification: vex.VulnerableCodeNotInExecutePath,
+			})
+		}
+	}
+}
+
+func (e *Enricher) runGovulncheck(ctx context.Context, absModDir string, goVersion string) (map[string][]*internal.Finding, error) {
+	args := []string{"-C", absModDir, "-format", "json", "-mode", "source"}
+	if e.offlineVulnDBPath != "" {
+		args = append(args, "-db=file://"+e.offlineVulnDBPath)
+	}
+	cmd := scan.Command(ctx, append(args, "./...")...)
+	var b bytes.Buffer
+	cmd.Stdout = &b
+	cmd.Env = append(os.Environ(), "GOVERSION=go"+goVersion)
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+	if err := cmd.Wait(); err != nil {
+		return nil, err
+	}
+
+	// Group the output of govulncheck based on the OSV ID.
+	h := &osvHandler{
+		idToFindings: map[string][]*internal.Finding{},
+	}
+	if err := handleJSON(bytes.NewReader(b.Bytes()), h); err != nil {
+		return nil, err
+	}
+
+	return h.idToFindings, nil
+}
+
+type osvHandler struct {
+	idToFindings map[string][]*internal.Finding
+}
+
+func (h *osvHandler) Finding(f *internal.Finding) {
+	h.idToFindings[f.OSV] = append(h.idToFindings[f.OSV], f)
+}
+
+func handleJSON(from io.Reader, to *osvHandler) error {
+	dec := json.NewDecoder(from)
+	for dec.More() {
+		msg := internal.Message{}
+		if err := dec.Decode(&msg); err != nil {
+			return err
+		}
+		if msg.Finding != nil {
+			to.Finding(msg.Finding)
+		}
+	}
+
+	return nil
+}
+
+func vulnHasImportsField(vuln *osvschema.Vulnerability, pkg *extractor.Package) bool {
+	for _, affected := range vuln.Affected {
+		if pkg != nil {
+			// TODO(#1559): Compare versions to see if this is the correct affected element
+			// This is very unlikely to ever matter however.
+			if affected.Package.Name != pkg.Name {
+				continue
+			}
+		}
+		_, hasImportsField := affected.EcosystemSpecific.GetFields()["imports"]
+		if hasImportsField {
+			return true
+		}
+	}
+
+	return false
+}
+
+// New returns a new govulncheck source enricher.
+func New(cfg *cpb.PluginConfig) enricher.Enricher {
+	e := &Enricher{}
+	specific := plugin.FindConfig(cfg, func(c *cpb.PluginSpecificConfig) *cpb.GovulncheckConfig { return c.GetGovulncheck() })
+	if specific != nil {
+		e.offlineVulnDBPath = specific.OfflineVulnDbPath
+	}
+	return e
+}