David K. Bainbridge | 215e024 | 2017-09-05 23:18:24 -0700 | [diff] [blame^] | 1 | package libtrust |
| 2 | |
| 3 | import ( |
| 4 | "crypto" |
| 5 | "crypto/rand" |
| 6 | "crypto/rsa" |
| 7 | "crypto/x509" |
| 8 | "encoding/json" |
| 9 | "encoding/pem" |
| 10 | "errors" |
| 11 | "fmt" |
| 12 | "io" |
| 13 | "math/big" |
| 14 | ) |
| 15 | |
| 16 | /* |
| 17 | * RSA DSA PUBLIC KEY |
| 18 | */ |
| 19 | |
| 20 | // rsaPublicKey implements a JWK Public Key using RSA digital signature algorithms. |
| 21 | type rsaPublicKey struct { |
| 22 | *rsa.PublicKey |
| 23 | extended map[string]interface{} |
| 24 | } |
| 25 | |
| 26 | func fromRSAPublicKey(cryptoPublicKey *rsa.PublicKey) *rsaPublicKey { |
| 27 | return &rsaPublicKey{cryptoPublicKey, map[string]interface{}{}} |
| 28 | } |
| 29 | |
| 30 | // KeyType returns the JWK key type for RSA keys, i.e., "RSA". |
| 31 | func (k *rsaPublicKey) KeyType() string { |
| 32 | return "RSA" |
| 33 | } |
| 34 | |
| 35 | // KeyID returns a distinct identifier which is unique to this Public Key. |
| 36 | func (k *rsaPublicKey) KeyID() string { |
| 37 | return keyIDFromCryptoKey(k) |
| 38 | } |
| 39 | |
| 40 | func (k *rsaPublicKey) String() string { |
| 41 | return fmt.Sprintf("RSA Public Key <%s>", k.KeyID()) |
| 42 | } |
| 43 | |
| 44 | // Verify verifyies the signature of the data in the io.Reader using this Public Key. |
| 45 | // The alg parameter should be the name of the JWA digital signature algorithm |
| 46 | // which was used to produce the signature and should be supported by this |
| 47 | // public key. Returns a nil error if the signature is valid. |
| 48 | func (k *rsaPublicKey) Verify(data io.Reader, alg string, signature []byte) error { |
| 49 | // Verify the signature of the given date, return non-nil error if valid. |
| 50 | sigAlg, err := rsaSignatureAlgorithmByName(alg) |
| 51 | if err != nil { |
| 52 | return fmt.Errorf("unable to verify Signature: %s", err) |
| 53 | } |
| 54 | |
| 55 | hasher := sigAlg.HashID().New() |
| 56 | _, err = io.Copy(hasher, data) |
| 57 | if err != nil { |
| 58 | return fmt.Errorf("error reading data to sign: %s", err) |
| 59 | } |
| 60 | hash := hasher.Sum(nil) |
| 61 | |
| 62 | err = rsa.VerifyPKCS1v15(k.PublicKey, sigAlg.HashID(), hash, signature) |
| 63 | if err != nil { |
| 64 | return fmt.Errorf("invalid %s signature: %s", sigAlg.HeaderParam(), err) |
| 65 | } |
| 66 | |
| 67 | return nil |
| 68 | } |
| 69 | |
| 70 | // CryptoPublicKey returns the internal object which can be used as a |
| 71 | // crypto.PublicKey for use with other standard library operations. The type |
| 72 | // is either *rsa.PublicKey or *ecdsa.PublicKey |
| 73 | func (k *rsaPublicKey) CryptoPublicKey() crypto.PublicKey { |
| 74 | return k.PublicKey |
| 75 | } |
| 76 | |
| 77 | func (k *rsaPublicKey) toMap() map[string]interface{} { |
| 78 | jwk := make(map[string]interface{}) |
| 79 | for k, v := range k.extended { |
| 80 | jwk[k] = v |
| 81 | } |
| 82 | jwk["kty"] = k.KeyType() |
| 83 | jwk["kid"] = k.KeyID() |
| 84 | jwk["n"] = joseBase64UrlEncode(k.N.Bytes()) |
| 85 | jwk["e"] = joseBase64UrlEncode(serializeRSAPublicExponentParam(k.E)) |
| 86 | |
| 87 | return jwk |
| 88 | } |
| 89 | |
| 90 | // MarshalJSON serializes this Public Key using the JWK JSON serialization format for |
| 91 | // RSA keys. |
| 92 | func (k *rsaPublicKey) MarshalJSON() (data []byte, err error) { |
| 93 | return json.Marshal(k.toMap()) |
| 94 | } |
| 95 | |
| 96 | // PEMBlock serializes this Public Key to DER-encoded PKIX format. |
| 97 | func (k *rsaPublicKey) PEMBlock() (*pem.Block, error) { |
| 98 | derBytes, err := x509.MarshalPKIXPublicKey(k.PublicKey) |
| 99 | if err != nil { |
| 100 | return nil, fmt.Errorf("unable to serialize RSA PublicKey to DER-encoded PKIX format: %s", err) |
| 101 | } |
| 102 | k.extended["kid"] = k.KeyID() // For display purposes. |
| 103 | return createPemBlock("PUBLIC KEY", derBytes, k.extended) |
| 104 | } |
| 105 | |
| 106 | func (k *rsaPublicKey) AddExtendedField(field string, value interface{}) { |
| 107 | k.extended[field] = value |
| 108 | } |
| 109 | |
| 110 | func (k *rsaPublicKey) GetExtendedField(field string) interface{} { |
| 111 | v, ok := k.extended[field] |
| 112 | if !ok { |
| 113 | return nil |
| 114 | } |
| 115 | return v |
| 116 | } |
| 117 | |
| 118 | func rsaPublicKeyFromMap(jwk map[string]interface{}) (*rsaPublicKey, error) { |
| 119 | // JWK key type (kty) has already been determined to be "RSA". |
| 120 | // Need to extract 'n', 'e', and 'kid' and check for |
| 121 | // consistency. |
| 122 | |
| 123 | // Get the modulus parameter N. |
| 124 | nB64Url, err := stringFromMap(jwk, "n") |
| 125 | if err != nil { |
| 126 | return nil, fmt.Errorf("JWK RSA Public Key modulus: %s", err) |
| 127 | } |
| 128 | |
| 129 | n, err := parseRSAModulusParam(nB64Url) |
| 130 | if err != nil { |
| 131 | return nil, fmt.Errorf("JWK RSA Public Key modulus: %s", err) |
| 132 | } |
| 133 | |
| 134 | // Get the public exponent E. |
| 135 | eB64Url, err := stringFromMap(jwk, "e") |
| 136 | if err != nil { |
| 137 | return nil, fmt.Errorf("JWK RSA Public Key exponent: %s", err) |
| 138 | } |
| 139 | |
| 140 | e, err := parseRSAPublicExponentParam(eB64Url) |
| 141 | if err != nil { |
| 142 | return nil, fmt.Errorf("JWK RSA Public Key exponent: %s", err) |
| 143 | } |
| 144 | |
| 145 | key := &rsaPublicKey{ |
| 146 | PublicKey: &rsa.PublicKey{N: n, E: e}, |
| 147 | } |
| 148 | |
| 149 | // Key ID is optional, but if it exists, it should match the key. |
| 150 | _, ok := jwk["kid"] |
| 151 | if ok { |
| 152 | kid, err := stringFromMap(jwk, "kid") |
| 153 | if err != nil { |
| 154 | return nil, fmt.Errorf("JWK RSA Public Key ID: %s", err) |
| 155 | } |
| 156 | if kid != key.KeyID() { |
| 157 | return nil, fmt.Errorf("JWK RSA Public Key ID does not match: %s", kid) |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | if _, ok := jwk["d"]; ok { |
| 162 | return nil, fmt.Errorf("JWK RSA Public Key cannot contain private exponent") |
| 163 | } |
| 164 | |
| 165 | key.extended = jwk |
| 166 | |
| 167 | return key, nil |
| 168 | } |
| 169 | |
| 170 | /* |
| 171 | * RSA DSA PRIVATE KEY |
| 172 | */ |
| 173 | |
| 174 | // rsaPrivateKey implements a JWK Private Key using RSA digital signature algorithms. |
| 175 | type rsaPrivateKey struct { |
| 176 | rsaPublicKey |
| 177 | *rsa.PrivateKey |
| 178 | } |
| 179 | |
| 180 | func fromRSAPrivateKey(cryptoPrivateKey *rsa.PrivateKey) *rsaPrivateKey { |
| 181 | return &rsaPrivateKey{ |
| 182 | *fromRSAPublicKey(&cryptoPrivateKey.PublicKey), |
| 183 | cryptoPrivateKey, |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | // PublicKey returns the Public Key data associated with this Private Key. |
| 188 | func (k *rsaPrivateKey) PublicKey() PublicKey { |
| 189 | return &k.rsaPublicKey |
| 190 | } |
| 191 | |
| 192 | func (k *rsaPrivateKey) String() string { |
| 193 | return fmt.Sprintf("RSA Private Key <%s>", k.KeyID()) |
| 194 | } |
| 195 | |
| 196 | // Sign signs the data read from the io.Reader using a signature algorithm supported |
| 197 | // by the RSA private key. If the specified hashing algorithm is supported by |
| 198 | // this key, that hash function is used to generate the signature otherwise the |
| 199 | // the default hashing algorithm for this key is used. Returns the signature |
| 200 | // and the name of the JWK signature algorithm used, e.g., "RS256", "RS384", |
| 201 | // "RS512". |
| 202 | func (k *rsaPrivateKey) Sign(data io.Reader, hashID crypto.Hash) (signature []byte, alg string, err error) { |
| 203 | // Generate a signature of the data using the internal alg. |
| 204 | sigAlg := rsaPKCS1v15SignatureAlgorithmForHashID(hashID) |
| 205 | hasher := sigAlg.HashID().New() |
| 206 | |
| 207 | _, err = io.Copy(hasher, data) |
| 208 | if err != nil { |
| 209 | return nil, "", fmt.Errorf("error reading data to sign: %s", err) |
| 210 | } |
| 211 | hash := hasher.Sum(nil) |
| 212 | |
| 213 | signature, err = rsa.SignPKCS1v15(rand.Reader, k.PrivateKey, sigAlg.HashID(), hash) |
| 214 | if err != nil { |
| 215 | return nil, "", fmt.Errorf("error producing signature: %s", err) |
| 216 | } |
| 217 | |
| 218 | alg = sigAlg.HeaderParam() |
| 219 | |
| 220 | return |
| 221 | } |
| 222 | |
| 223 | // CryptoPrivateKey returns the internal object which can be used as a |
| 224 | // crypto.PublicKey for use with other standard library operations. The type |
| 225 | // is either *rsa.PublicKey or *ecdsa.PublicKey |
| 226 | func (k *rsaPrivateKey) CryptoPrivateKey() crypto.PrivateKey { |
| 227 | return k.PrivateKey |
| 228 | } |
| 229 | |
| 230 | func (k *rsaPrivateKey) toMap() map[string]interface{} { |
| 231 | k.Precompute() // Make sure the precomputed values are stored. |
| 232 | jwk := k.rsaPublicKey.toMap() |
| 233 | |
| 234 | jwk["d"] = joseBase64UrlEncode(k.D.Bytes()) |
| 235 | jwk["p"] = joseBase64UrlEncode(k.Primes[0].Bytes()) |
| 236 | jwk["q"] = joseBase64UrlEncode(k.Primes[1].Bytes()) |
| 237 | jwk["dp"] = joseBase64UrlEncode(k.Precomputed.Dp.Bytes()) |
| 238 | jwk["dq"] = joseBase64UrlEncode(k.Precomputed.Dq.Bytes()) |
| 239 | jwk["qi"] = joseBase64UrlEncode(k.Precomputed.Qinv.Bytes()) |
| 240 | |
| 241 | otherPrimes := k.Primes[2:] |
| 242 | |
| 243 | if len(otherPrimes) > 0 { |
| 244 | otherPrimesInfo := make([]interface{}, len(otherPrimes)) |
| 245 | for i, r := range otherPrimes { |
| 246 | otherPrimeInfo := make(map[string]string, 3) |
| 247 | otherPrimeInfo["r"] = joseBase64UrlEncode(r.Bytes()) |
| 248 | crtVal := k.Precomputed.CRTValues[i] |
| 249 | otherPrimeInfo["d"] = joseBase64UrlEncode(crtVal.Exp.Bytes()) |
| 250 | otherPrimeInfo["t"] = joseBase64UrlEncode(crtVal.Coeff.Bytes()) |
| 251 | otherPrimesInfo[i] = otherPrimeInfo |
| 252 | } |
| 253 | jwk["oth"] = otherPrimesInfo |
| 254 | } |
| 255 | |
| 256 | return jwk |
| 257 | } |
| 258 | |
| 259 | // MarshalJSON serializes this Private Key using the JWK JSON serialization format for |
| 260 | // RSA keys. |
| 261 | func (k *rsaPrivateKey) MarshalJSON() (data []byte, err error) { |
| 262 | return json.Marshal(k.toMap()) |
| 263 | } |
| 264 | |
| 265 | // PEMBlock serializes this Private Key to DER-encoded PKIX format. |
| 266 | func (k *rsaPrivateKey) PEMBlock() (*pem.Block, error) { |
| 267 | derBytes := x509.MarshalPKCS1PrivateKey(k.PrivateKey) |
| 268 | k.extended["keyID"] = k.KeyID() // For display purposes. |
| 269 | return createPemBlock("RSA PRIVATE KEY", derBytes, k.extended) |
| 270 | } |
| 271 | |
| 272 | func rsaPrivateKeyFromMap(jwk map[string]interface{}) (*rsaPrivateKey, error) { |
| 273 | // The JWA spec for RSA Private Keys (draft rfc section 5.3.2) states that |
| 274 | // only the private key exponent 'd' is REQUIRED, the others are just for |
| 275 | // signature/decryption optimizations and SHOULD be included when the JWK |
| 276 | // is produced. We MAY choose to accept a JWK which only includes 'd', but |
| 277 | // we're going to go ahead and not choose to accept it without the extra |
| 278 | // fields. Only the 'oth' field will be optional (for multi-prime keys). |
| 279 | privateExponent, err := parseRSAPrivateKeyParamFromMap(jwk, "d") |
| 280 | if err != nil { |
| 281 | return nil, fmt.Errorf("JWK RSA Private Key exponent: %s", err) |
| 282 | } |
| 283 | firstPrimeFactor, err := parseRSAPrivateKeyParamFromMap(jwk, "p") |
| 284 | if err != nil { |
| 285 | return nil, fmt.Errorf("JWK RSA Private Key prime factor: %s", err) |
| 286 | } |
| 287 | secondPrimeFactor, err := parseRSAPrivateKeyParamFromMap(jwk, "q") |
| 288 | if err != nil { |
| 289 | return nil, fmt.Errorf("JWK RSA Private Key prime factor: %s", err) |
| 290 | } |
| 291 | firstFactorCRT, err := parseRSAPrivateKeyParamFromMap(jwk, "dp") |
| 292 | if err != nil { |
| 293 | return nil, fmt.Errorf("JWK RSA Private Key CRT exponent: %s", err) |
| 294 | } |
| 295 | secondFactorCRT, err := parseRSAPrivateKeyParamFromMap(jwk, "dq") |
| 296 | if err != nil { |
| 297 | return nil, fmt.Errorf("JWK RSA Private Key CRT exponent: %s", err) |
| 298 | } |
| 299 | crtCoeff, err := parseRSAPrivateKeyParamFromMap(jwk, "qi") |
| 300 | if err != nil { |
| 301 | return nil, fmt.Errorf("JWK RSA Private Key CRT coefficient: %s", err) |
| 302 | } |
| 303 | |
| 304 | var oth interface{} |
| 305 | if _, ok := jwk["oth"]; ok { |
| 306 | oth = jwk["oth"] |
| 307 | delete(jwk, "oth") |
| 308 | } |
| 309 | |
| 310 | // JWK key type (kty) has already been determined to be "RSA". |
| 311 | // Need to extract the public key information, then extract the private |
| 312 | // key values. |
| 313 | publicKey, err := rsaPublicKeyFromMap(jwk) |
| 314 | if err != nil { |
| 315 | return nil, err |
| 316 | } |
| 317 | |
| 318 | privateKey := &rsa.PrivateKey{ |
| 319 | PublicKey: *publicKey.PublicKey, |
| 320 | D: privateExponent, |
| 321 | Primes: []*big.Int{firstPrimeFactor, secondPrimeFactor}, |
| 322 | Precomputed: rsa.PrecomputedValues{ |
| 323 | Dp: firstFactorCRT, |
| 324 | Dq: secondFactorCRT, |
| 325 | Qinv: crtCoeff, |
| 326 | }, |
| 327 | } |
| 328 | |
| 329 | if oth != nil { |
| 330 | // Should be an array of more JSON objects. |
| 331 | otherPrimesInfo, ok := oth.([]interface{}) |
| 332 | if !ok { |
| 333 | return nil, errors.New("JWK RSA Private Key: Invalid other primes info: must be an array") |
| 334 | } |
| 335 | numOtherPrimeFactors := len(otherPrimesInfo) |
| 336 | if numOtherPrimeFactors == 0 { |
| 337 | return nil, errors.New("JWK RSA Privake Key: Invalid other primes info: must be absent or non-empty") |
| 338 | } |
| 339 | otherPrimeFactors := make([]*big.Int, numOtherPrimeFactors) |
| 340 | productOfPrimes := new(big.Int).Mul(firstPrimeFactor, secondPrimeFactor) |
| 341 | crtValues := make([]rsa.CRTValue, numOtherPrimeFactors) |
| 342 | |
| 343 | for i, val := range otherPrimesInfo { |
| 344 | otherPrimeinfo, ok := val.(map[string]interface{}) |
| 345 | if !ok { |
| 346 | return nil, errors.New("JWK RSA Private Key: Invalid other prime info: must be a JSON object") |
| 347 | } |
| 348 | |
| 349 | otherPrimeFactor, err := parseRSAPrivateKeyParamFromMap(otherPrimeinfo, "r") |
| 350 | if err != nil { |
| 351 | return nil, fmt.Errorf("JWK RSA Private Key prime factor: %s", err) |
| 352 | } |
| 353 | otherFactorCRT, err := parseRSAPrivateKeyParamFromMap(otherPrimeinfo, "d") |
| 354 | if err != nil { |
| 355 | return nil, fmt.Errorf("JWK RSA Private Key CRT exponent: %s", err) |
| 356 | } |
| 357 | otherCrtCoeff, err := parseRSAPrivateKeyParamFromMap(otherPrimeinfo, "t") |
| 358 | if err != nil { |
| 359 | return nil, fmt.Errorf("JWK RSA Private Key CRT coefficient: %s", err) |
| 360 | } |
| 361 | |
| 362 | crtValue := crtValues[i] |
| 363 | crtValue.Exp = otherFactorCRT |
| 364 | crtValue.Coeff = otherCrtCoeff |
| 365 | crtValue.R = productOfPrimes |
| 366 | otherPrimeFactors[i] = otherPrimeFactor |
| 367 | productOfPrimes = new(big.Int).Mul(productOfPrimes, otherPrimeFactor) |
| 368 | } |
| 369 | |
| 370 | privateKey.Primes = append(privateKey.Primes, otherPrimeFactors...) |
| 371 | privateKey.Precomputed.CRTValues = crtValues |
| 372 | } |
| 373 | |
| 374 | key := &rsaPrivateKey{ |
| 375 | rsaPublicKey: *publicKey, |
| 376 | PrivateKey: privateKey, |
| 377 | } |
| 378 | |
| 379 | return key, nil |
| 380 | } |
| 381 | |
| 382 | /* |
| 383 | * Key Generation Functions. |
| 384 | */ |
| 385 | |
| 386 | func generateRSAPrivateKey(bits int) (k *rsaPrivateKey, err error) { |
| 387 | k = new(rsaPrivateKey) |
| 388 | k.PrivateKey, err = rsa.GenerateKey(rand.Reader, bits) |
| 389 | if err != nil { |
| 390 | return nil, err |
| 391 | } |
| 392 | |
| 393 | k.rsaPublicKey.PublicKey = &k.PrivateKey.PublicKey |
| 394 | k.extended = make(map[string]interface{}) |
| 395 | |
| 396 | return |
| 397 | } |
| 398 | |
| 399 | // GenerateRSA2048PrivateKey generates a key pair using 2048-bit RSA. |
| 400 | func GenerateRSA2048PrivateKey() (PrivateKey, error) { |
| 401 | k, err := generateRSAPrivateKey(2048) |
| 402 | if err != nil { |
| 403 | return nil, fmt.Errorf("error generating RSA 2048-bit key: %s", err) |
| 404 | } |
| 405 | |
| 406 | return k, nil |
| 407 | } |
| 408 | |
| 409 | // GenerateRSA3072PrivateKey generates a key pair using 3072-bit RSA. |
| 410 | func GenerateRSA3072PrivateKey() (PrivateKey, error) { |
| 411 | k, err := generateRSAPrivateKey(3072) |
| 412 | if err != nil { |
| 413 | return nil, fmt.Errorf("error generating RSA 3072-bit key: %s", err) |
| 414 | } |
| 415 | |
| 416 | return k, nil |
| 417 | } |
| 418 | |
| 419 | // GenerateRSA4096PrivateKey generates a key pair using 4096-bit RSA. |
| 420 | func GenerateRSA4096PrivateKey() (PrivateKey, error) { |
| 421 | k, err := generateRSAPrivateKey(4096) |
| 422 | if err != nil { |
| 423 | return nil, fmt.Errorf("error generating RSA 4096-bit key: %s", err) |
| 424 | } |
| 425 | |
| 426 | return k, nil |
| 427 | } |