|
| 1 | +package oauth2 |
| 2 | + |
| 3 | +import ( |
| 4 | + "crypto" |
| 5 | + "encoding/base64" |
| 6 | + "encoding/json" |
| 7 | + "net/http" |
| 8 | + "time" |
| 9 | + |
| 10 | + "github.com/go-jose/go-jose/v3" |
| 11 | + "github.com/google/uuid" |
| 12 | + "github.com/pkg/errors" |
| 13 | +) |
| 14 | + |
| 15 | +const ( |
| 16 | + DPoPHeaderName = "DPoP" |
| 17 | + DPoPHeaderType = "dpop+jwt" |
| 18 | +) |
| 19 | + |
| 20 | +type DPoPClaims struct { |
| 21 | + Htm string `json:"htm"` |
| 22 | + Htu string `json:"htu"` |
| 23 | + Jti string `json:"jti"` |
| 24 | + IssuedAt int64 `json:"iat"` |
| 25 | +} |
| 26 | + |
| 27 | +func DPoPSignRequest(signingKey string, hc *http.Client, r *http.Request) error { |
| 28 | + var ( |
| 29 | + key jose.JSONWebKey |
| 30 | + proof string |
| 31 | + signer jose.Signer |
| 32 | + bytes []byte |
| 33 | + signature *jose.JSONWebSignature |
| 34 | + err error |
| 35 | + ) |
| 36 | + |
| 37 | + if key, err = ReadKey(SigningKey, signingKey, hc); err != nil { |
| 38 | + return errors.Wrapf(err, "failed to read signing key from %s", signingKey) |
| 39 | + } |
| 40 | + |
| 41 | + if key.Algorithm == "" { |
| 42 | + return errors.New("signing key algorithm must be set") |
| 43 | + } |
| 44 | + |
| 45 | + if key.IsPublic() { |
| 46 | + return errors.New("signing key must be private") |
| 47 | + } |
| 48 | + |
| 49 | + if !key.Valid() { |
| 50 | + return errors.New("signing key is not valid") |
| 51 | + } |
| 52 | + |
| 53 | + sig := jose.SigningKey{ |
| 54 | + Algorithm: jose.SignatureAlgorithm(key.Algorithm), |
| 55 | + Key: key.Key, |
| 56 | + } |
| 57 | + |
| 58 | + opts := &jose.SignerOptions{ |
| 59 | + ExtraHeaders: map[jose.HeaderKey]interface{}{ |
| 60 | + jose.HeaderType: DPoPHeaderType, |
| 61 | + }, |
| 62 | + EmbedJWK: true, |
| 63 | + } |
| 64 | + |
| 65 | + if signer, err = jose.NewSigner(sig, opts); err != nil { |
| 66 | + return errors.Wrapf(err, "failed to create signer") |
| 67 | + } |
| 68 | + |
| 69 | + claims := DPoPClaims{ |
| 70 | + Htm: r.Method, |
| 71 | + Htu: r.URL.String(), |
| 72 | + Jti: uuid.New().String(), |
| 73 | + IssuedAt: time.Now().Unix(), |
| 74 | + } |
| 75 | + |
| 76 | + if bytes, err = json.Marshal(claims); err != nil { |
| 77 | + return err |
| 78 | + } |
| 79 | + |
| 80 | + if signature, err = signer.Sign(bytes); err != nil { |
| 81 | + return err |
| 82 | + } |
| 83 | + |
| 84 | + if proof, err = signature.CompactSerialize(); err != nil { |
| 85 | + return err |
| 86 | + } |
| 87 | + |
| 88 | + r.Header.Set(DPoPHeaderName, proof) |
| 89 | + |
| 90 | + return nil |
| 91 | +} |
| 92 | + |
| 93 | +func DPoPThumbprint(signingKey string, hc *http.Client) (string, error) { |
| 94 | + var ( |
| 95 | + key jose.JSONWebKey |
| 96 | + thumbprint []byte |
| 97 | + err error |
| 98 | + ) |
| 99 | + |
| 100 | + if key, err = ReadKey(SigningKey, signingKey, hc); err != nil { |
| 101 | + return "", errors.Wrapf(err, "failed to read signing key from %s", signingKey) |
| 102 | + } |
| 103 | + |
| 104 | + public := key.Public() |
| 105 | + |
| 106 | + if thumbprint, err = public.Thumbprint(crypto.SHA256); err != nil { |
| 107 | + return "", err |
| 108 | + } |
| 109 | + |
| 110 | + return base64.RawURLEncoding.EncodeToString(thumbprint), nil |
| 111 | +} |
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