|
| 1 | +package application |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "encoding/json" |
| 6 | + "encoding/json/jsontext" |
| 7 | + "errors" |
| 8 | + "fmt" |
| 9 | +) |
| 10 | + |
| 11 | +const aiBOMSignatureProperty = "sbomAuthorSignature" |
| 12 | + |
| 13 | +func (v *VerifierApp) VerifyAIBOMEmbeddedVersioned( |
| 14 | + signedSBOM []byte, |
| 15 | + publicKeyPEM string, |
| 16 | + version VerificationVersion, |
| 17 | +) (*VerificationResult, error) { |
| 18 | + if version != VerificationV2 { |
| 19 | + return nil, errors.New("AI-BOM verification requires verification version v2") |
| 20 | + } |
| 21 | + return v.VerifyAIBOMEmbeddedV2(signedSBOM, publicKeyPEM) |
| 22 | +} |
| 23 | + |
| 24 | +func (v *VerifierApp) VerifyAIBOMEmbeddedV2(signedSBOM []byte, publicKeyPEM string) (*VerificationResult, error) { |
| 25 | + if err := validateSBOM(signedSBOM, "AI-BOM"); err != nil { |
| 26 | + return nil, err |
| 27 | + } |
| 28 | + |
| 29 | + canonical, signatureValue, algorithm, err := canonicalizeEmbeddedAIBOMForV2(signedSBOM) |
| 30 | + if err != nil { |
| 31 | + return nil, err |
| 32 | + } |
| 33 | + |
| 34 | + return v.verifyCanonicalJSON(canonical, signatureValue, publicKeyPEM, algorithm, "AI-BOM signature is valid", "ecdsa") |
| 35 | +} |
| 36 | + |
| 37 | +func canonicalizeEmbeddedAIBOMForV2(signedSBOM []byte) ([]byte, string, string, error) { |
| 38 | + obj, signatureObj, err := extractAIBOMSignatureObject(signedSBOM) |
| 39 | + if err != nil { |
| 40 | + return nil, "", "", err |
| 41 | + } |
| 42 | + |
| 43 | + signatureValue, algorithm, err := decodeEmbeddedSignatureFields(signatureObj) |
| 44 | + if err != nil { |
| 45 | + return nil, "", "", err |
| 46 | + } |
| 47 | + |
| 48 | + delete(signatureObj, "value") |
| 49 | + |
| 50 | + rawNoValue, err := json.Marshal(obj) |
| 51 | + if err != nil { |
| 52 | + return nil, "", "", fmt.Errorf("failed to serialize JSON: %w", err) |
| 53 | + } |
| 54 | + |
| 55 | + canonical := jsontext.Value(rawNoValue) |
| 56 | + if err := canonical.Canonicalize(); err != nil { |
| 57 | + return nil, "", "", fmt.Errorf("failed to canonicalize JSON: %w", err) |
| 58 | + } |
| 59 | + |
| 60 | + return []byte(canonical), signatureValue, algorithm, nil |
| 61 | +} |
| 62 | + |
| 63 | +func extractAIBOMSignatureObject(signedSBOM []byte) (map[string]any, map[string]any, error) { |
| 64 | + var obj map[string]any |
| 65 | + dec := json.NewDecoder(bytes.NewReader(signedSBOM)) |
| 66 | + dec.UseNumber() |
| 67 | + if err := dec.Decode(&obj); err != nil { |
| 68 | + return nil, nil, fmt.Errorf("invalid AI-BOM JSON: %w", err) |
| 69 | + } |
| 70 | + |
| 71 | + metadataAny, ok := obj["metadata"] |
| 72 | + if !ok { |
| 73 | + return nil, nil, errors.New("metadata object is missing") |
| 74 | + } |
| 75 | + |
| 76 | + metadata, ok := metadataAny.(map[string]any) |
| 77 | + if !ok { |
| 78 | + return nil, nil, errors.New("metadata must be an object") |
| 79 | + } |
| 80 | + |
| 81 | + sigAny, ok := metadata[aiBOMSignatureProperty] |
| 82 | + if !ok { |
| 83 | + return nil, nil, fmt.Errorf("%s object is missing", aiBOMSignatureProperty) |
| 84 | + } |
| 85 | + |
| 86 | + sigObj, ok := sigAny.(map[string]any) |
| 87 | + if !ok { |
| 88 | + return nil, nil, fmt.Errorf("%s must be an object", aiBOMSignatureProperty) |
| 89 | + } |
| 90 | + |
| 91 | + return obj, sigObj, nil |
| 92 | +} |
| 93 | + |
| 94 | +func decodeEmbeddedSignatureFields(sigFields map[string]any) (string, string, error) { |
| 95 | + signatureValue, ok := sigFields["value"].(string) |
| 96 | + if !ok || signatureValue == "" { |
| 97 | + return "", "", errors.New("signature value missing or invalid") |
| 98 | + } |
| 99 | + |
| 100 | + algorithm, _ := sigFields["alg"].(string) |
| 101 | + if algorithm == "" { |
| 102 | + algorithm, _ = sigFields["algorithm"].(string) |
| 103 | + } |
| 104 | + if algorithm == "" { |
| 105 | + algorithm = "ES256" |
| 106 | + } |
| 107 | + |
| 108 | + return signatureValue, algorithm, nil |
| 109 | +} |
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