|
| 1 | +package vex |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "fmt" |
| 6 | + "io" |
| 7 | + "net/http" |
| 8 | + "net/url" |
| 9 | + |
| 10 | + "golang.org/x/xerrors" |
| 11 | + |
| 12 | + "github.com/aquasecurity/trivy/pkg/fanal/artifact" |
| 13 | + "github.com/aquasecurity/trivy/pkg/log" |
| 14 | + "github.com/aquasecurity/trivy/pkg/sbom/core" |
| 15 | + "github.com/aquasecurity/trivy/pkg/types" |
| 16 | +) |
| 17 | + |
| 18 | +type SBOMReferenceSet struct { |
| 19 | + VEXes []VEX |
| 20 | +} |
| 21 | + |
| 22 | +func NewSBOMReferenceSet(report *types.Report) (*SBOMReferenceSet, error) { |
| 23 | + |
| 24 | + if report.ArtifactType != artifact.TypeCycloneDX { |
| 25 | + return nil, xerrors.Errorf("externalReferences can only be used when scanning CycloneDX SBOMs: %w", report.ArtifactType) |
| 26 | + } |
| 27 | + |
| 28 | + var externalRefs = report.BOM.ExternalReferences() |
| 29 | + urls := parseToURLs(externalRefs) |
| 30 | + |
| 31 | + v, err := retrieveExternalVEXDocuments(urls, report) |
| 32 | + if err != nil { |
| 33 | + return nil, xerrors.Errorf("failed to fetch external VEX documents: %w", err) |
| 34 | + } else if v == nil { |
| 35 | + return nil, nil |
| 36 | + } |
| 37 | + |
| 38 | + return &SBOMReferenceSet{VEXes: v}, nil |
| 39 | +} |
| 40 | + |
| 41 | +func parseToURLs(refs []core.ExternalReference) []url.URL { |
| 42 | + var urls []url.URL |
| 43 | + for _, ref := range refs { |
| 44 | + if ref.Type == core.ExternalReferenceVEX { |
| 45 | + val, err := url.Parse(ref.URL) |
| 46 | + // do not concern ourselves with relative URLs at this point |
| 47 | + if err != nil || (val.Scheme != "https" && val.Scheme != "http") { |
| 48 | + continue |
| 49 | + } |
| 50 | + urls = append(urls, *val) |
| 51 | + } |
| 52 | + } |
| 53 | + return urls |
| 54 | +} |
| 55 | + |
| 56 | +func retrieveExternalVEXDocuments(refs []url.URL, report *types.Report) ([]VEX, error) { |
| 57 | + |
| 58 | + logger := log.WithPrefix("vex").With(log.String("type", "external_reference")) |
| 59 | + |
| 60 | + var docs []VEX |
| 61 | + for _, ref := range refs { |
| 62 | + doc, err := retrieveExternalVEXDocument(ref, report) |
| 63 | + if err != nil { |
| 64 | + return nil, xerrors.Errorf("failed to retrieve external VEX document: %w", err) |
| 65 | + } |
| 66 | + docs = append(docs, doc) |
| 67 | + } |
| 68 | + logger.Debug("Retrieved external VEX documents", "count", len(docs)) |
| 69 | + |
| 70 | + if len(docs) == 0 { |
| 71 | + logger.Info("No external VEX documents found") |
| 72 | + return nil, nil |
| 73 | + } |
| 74 | + return docs, nil |
| 75 | + |
| 76 | +} |
| 77 | + |
| 78 | +func retrieveExternalVEXDocument(vexUrl url.URL, report *types.Report) (VEX, error) { |
| 79 | + |
| 80 | + logger := log.WithPrefix("vex").With(log.String("type", "external_reference")) |
| 81 | + |
| 82 | + logger.Info(fmt.Sprintf("Retrieving external VEX document from host %s", vexUrl.Host)) |
| 83 | + |
| 84 | + res, err := http.Get(vexUrl.String()) |
| 85 | + if err != nil { |
| 86 | + return nil, xerrors.Errorf("unable to fetch file via HTTP: %w", err) |
| 87 | + } |
| 88 | + defer res.Body.Close() |
| 89 | + |
| 90 | + if res.StatusCode != http.StatusOK { |
| 91 | + return nil, xerrors.Errorf("did not receive 2xx status code: %w", res.StatusCode) |
| 92 | + } |
| 93 | + |
| 94 | + val, err := io.ReadAll(res.Body) |
| 95 | + if err != nil { |
| 96 | + return nil, xerrors.Errorf("unable to read response into memory: %w", err) |
| 97 | + } |
| 98 | + |
| 99 | + if v, err := decodeVEX(bytes.NewReader(val), vexUrl.String(), report); err != nil { |
| 100 | + return nil, xerrors.Errorf("unable to load VEX from external reference: %w", err) |
| 101 | + } else { |
| 102 | + return v, nil |
| 103 | + } |
| 104 | +} |
| 105 | + |
| 106 | +func (set *SBOMReferenceSet) NotAffected(vuln types.DetectedVulnerability, product, subComponent *core.Component) (types.ModifiedFinding, bool) { |
| 107 | + |
| 108 | + for _, vex := range set.VEXes { |
| 109 | + if m, notAffected := vex.NotAffected(vuln, product, subComponent); notAffected { |
| 110 | + return m, notAffected |
| 111 | + } |
| 112 | + } |
| 113 | + return types.ModifiedFinding{}, false |
| 114 | +} |
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