533 lines
14 KiB
Go
533 lines
14 KiB
Go
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package httpsig
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import (
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"crypto"
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"crypto/ecdsa"
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"crypto/hmac"
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"crypto/rsa"
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"crypto/sha1"
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"crypto/sha256"
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"crypto/sha512"
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"crypto/subtle" // Use should trigger great care
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"encoding/asn1"
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"errors"
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"fmt"
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"hash"
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"io"
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"math/big"
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"strings"
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"golang.org/x/crypto/blake2b"
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"golang.org/x/crypto/blake2s"
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"golang.org/x/crypto/ed25519"
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"golang.org/x/crypto/ripemd160"
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"golang.org/x/crypto/sha3"
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"golang.org/x/crypto/ssh"
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)
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const (
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hmacPrefix = "hmac"
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rsaPrefix = "rsa"
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sshPrefix = "ssh"
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ecdsaPrefix = "ecdsa"
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ed25519Prefix = "ed25519"
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md4String = "md4"
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md5String = "md5"
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sha1String = "sha1"
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sha224String = "sha224"
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sha256String = "sha256"
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sha384String = "sha384"
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sha512String = "sha512"
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md5sha1String = "md5sha1"
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ripemd160String = "ripemd160"
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sha3_224String = "sha3-224"
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sha3_256String = "sha3-256"
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sha3_384String = "sha3-384"
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sha3_512String = "sha3-512"
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sha512_224String = "sha512-224"
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sha512_256String = "sha512-256"
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blake2s_256String = "blake2s-256"
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blake2b_256String = "blake2b-256"
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blake2b_384String = "blake2b-384"
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blake2b_512String = "blake2b-512"
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)
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var blake2Algorithms = map[crypto.Hash]bool{
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crypto.BLAKE2s_256: true,
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crypto.BLAKE2b_256: true,
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crypto.BLAKE2b_384: true,
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crypto.BLAKE2b_512: true,
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}
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var hashToDef = map[crypto.Hash]struct {
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name string
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new func(key []byte) (hash.Hash, error) // Only MACers will accept a key
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}{
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// Which standard names these?
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// The spec lists the following as a canonical reference, which is dead:
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// http://www.iana.org/assignments/signature-algorithms
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//
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// Note that the forbidden hashes have an invalid 'new' function.
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crypto.MD4: {md4String, func(key []byte) (hash.Hash, error) { return nil, nil }},
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crypto.MD5: {md5String, func(key []byte) (hash.Hash, error) { return nil, nil }},
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// Temporarily enable SHA1 because of issue https://github.com/golang/go/issues/37278
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crypto.SHA1: {sha1String, func(key []byte) (hash.Hash, error) { return sha1.New(), nil }},
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crypto.SHA224: {sha224String, func(key []byte) (hash.Hash, error) { return sha256.New224(), nil }},
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crypto.SHA256: {sha256String, func(key []byte) (hash.Hash, error) { return sha256.New(), nil }},
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crypto.SHA384: {sha384String, func(key []byte) (hash.Hash, error) { return sha512.New384(), nil }},
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crypto.SHA512: {sha512String, func(key []byte) (hash.Hash, error) { return sha512.New(), nil }},
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crypto.MD5SHA1: {md5sha1String, func(key []byte) (hash.Hash, error) { return nil, nil }},
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crypto.RIPEMD160: {ripemd160String, func(key []byte) (hash.Hash, error) { return ripemd160.New(), nil }},
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crypto.SHA3_224: {sha3_224String, func(key []byte) (hash.Hash, error) { return sha3.New224(), nil }},
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crypto.SHA3_256: {sha3_256String, func(key []byte) (hash.Hash, error) { return sha3.New256(), nil }},
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crypto.SHA3_384: {sha3_384String, func(key []byte) (hash.Hash, error) { return sha3.New384(), nil }},
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crypto.SHA3_512: {sha3_512String, func(key []byte) (hash.Hash, error) { return sha3.New512(), nil }},
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crypto.SHA512_224: {sha512_224String, func(key []byte) (hash.Hash, error) { return sha512.New512_224(), nil }},
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crypto.SHA512_256: {sha512_256String, func(key []byte) (hash.Hash, error) { return sha512.New512_256(), nil }},
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crypto.BLAKE2s_256: {blake2s_256String, func(key []byte) (hash.Hash, error) { return blake2s.New256(key) }},
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crypto.BLAKE2b_256: {blake2b_256String, func(key []byte) (hash.Hash, error) { return blake2b.New256(key) }},
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crypto.BLAKE2b_384: {blake2b_384String, func(key []byte) (hash.Hash, error) { return blake2b.New384(key) }},
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crypto.BLAKE2b_512: {blake2b_512String, func(key []byte) (hash.Hash, error) { return blake2b.New512(key) }},
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}
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var stringToHash map[string]crypto.Hash
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const (
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defaultAlgorithm = RSA_SHA256
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defaultAlgorithmHashing = sha256String
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)
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func init() {
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stringToHash = make(map[string]crypto.Hash, len(hashToDef))
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for k, v := range hashToDef {
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stringToHash[v.name] = k
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}
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// This should guarantee that at runtime the defaultAlgorithm will not
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// result in errors when fetching a macer or signer (see algorithms.go)
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if ok, err := isAvailable(string(defaultAlgorithmHashing)); err != nil {
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panic(err)
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} else if !ok {
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panic(fmt.Sprintf("the default httpsig algorithm is unavailable: %q", defaultAlgorithm))
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}
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}
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func isForbiddenHash(h crypto.Hash) bool {
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switch h {
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// Not actually cryptographically secure
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case crypto.MD4:
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fallthrough
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case crypto.MD5:
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fallthrough
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case crypto.MD5SHA1: // shorthand for crypto/tls, not actually implemented
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return true
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}
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// Still cryptographically secure
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return false
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}
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// signer is an internally public type.
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type signer interface {
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Sign(rand io.Reader, p crypto.PrivateKey, sig []byte) ([]byte, error)
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Verify(pub crypto.PublicKey, toHash, signature []byte) error
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String() string
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}
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// macer is an internally public type.
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type macer interface {
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Sign(sig, key []byte) ([]byte, error)
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Equal(sig, actualMAC, key []byte) (bool, error)
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String() string
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}
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var _ macer = &hmacAlgorithm{}
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type hmacAlgorithm struct {
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fn func(key []byte) (hash.Hash, error)
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kind crypto.Hash
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}
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func (h *hmacAlgorithm) Sign(sig, key []byte) ([]byte, error) {
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hs, err := h.fn(key)
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if err = setSig(hs, sig); err != nil {
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return nil, err
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}
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return hs.Sum(nil), nil
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}
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func (h *hmacAlgorithm) Equal(sig, actualMAC, key []byte) (bool, error) {
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hs, err := h.fn(key)
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if err != nil {
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return false, err
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}
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defer hs.Reset()
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err = setSig(hs, sig)
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if err != nil {
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return false, err
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}
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expected := hs.Sum(nil)
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return hmac.Equal(actualMAC, expected), nil
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}
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func (h *hmacAlgorithm) String() string {
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return fmt.Sprintf("%s-%s", hmacPrefix, hashToDef[h.kind].name)
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}
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var _ signer = &rsaAlgorithm{}
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type rsaAlgorithm struct {
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hash.Hash
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kind crypto.Hash
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sshSigner ssh.Signer
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}
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func (r *rsaAlgorithm) setSig(b []byte) error {
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n, err := r.Write(b)
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if err != nil {
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r.Reset()
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return err
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} else if n != len(b) {
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r.Reset()
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return fmt.Errorf("could only write %d of %d bytes of signature to hash", n, len(b))
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}
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return nil
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}
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func (r *rsaAlgorithm) Sign(rand io.Reader, p crypto.PrivateKey, sig []byte) ([]byte, error) {
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if r.sshSigner != nil {
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sshsig, err := r.sshSigner.Sign(rand, sig)
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if err != nil {
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return nil, err
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}
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return sshsig.Blob, nil
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}
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defer r.Reset()
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if err := r.setSig(sig); err != nil {
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return nil, err
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}
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rsaK, ok := p.(*rsa.PrivateKey)
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if !ok {
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return nil, errors.New("crypto.PrivateKey is not *rsa.PrivateKey")
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}
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return rsa.SignPKCS1v15(rand, rsaK, r.kind, r.Sum(nil))
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}
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func (r *rsaAlgorithm) Verify(pub crypto.PublicKey, toHash, signature []byte) error {
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defer r.Reset()
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rsaK, ok := pub.(*rsa.PublicKey)
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if !ok {
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return errors.New("crypto.PublicKey is not *rsa.PublicKey")
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}
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if err := r.setSig(toHash); err != nil {
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return err
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}
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return rsa.VerifyPKCS1v15(rsaK, r.kind, r.Sum(nil), signature)
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}
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func (r *rsaAlgorithm) String() string {
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return fmt.Sprintf("%s-%s", rsaPrefix, hashToDef[r.kind].name)
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}
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var _ signer = &ed25519Algorithm{}
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type ed25519Algorithm struct {
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sshSigner ssh.Signer
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}
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func (r *ed25519Algorithm) Sign(rand io.Reader, p crypto.PrivateKey, sig []byte) ([]byte, error) {
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if r.sshSigner != nil {
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sshsig, err := r.sshSigner.Sign(rand, sig)
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if err != nil {
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return nil, err
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}
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return sshsig.Blob, nil
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}
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ed25519K, ok := p.(ed25519.PrivateKey)
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if !ok {
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return nil, errors.New("crypto.PrivateKey is not ed25519.PrivateKey")
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}
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return ed25519.Sign(ed25519K, sig), nil
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}
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func (r *ed25519Algorithm) Verify(pub crypto.PublicKey, toHash, signature []byte) error {
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ed25519K, ok := pub.(ed25519.PublicKey)
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if !ok {
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return errors.New("crypto.PublicKey is not ed25519.PublicKey")
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}
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if ed25519.Verify(ed25519K, toHash, signature) {
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return nil
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}
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return errors.New("ed25519 verify failed")
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}
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func (r *ed25519Algorithm) String() string {
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return fmt.Sprintf("%s", ed25519Prefix)
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}
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var _ signer = &ecdsaAlgorithm{}
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type ecdsaAlgorithm struct {
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hash.Hash
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kind crypto.Hash
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}
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func (r *ecdsaAlgorithm) setSig(b []byte) error {
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n, err := r.Write(b)
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if err != nil {
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r.Reset()
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return err
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} else if n != len(b) {
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r.Reset()
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return fmt.Errorf("could only write %d of %d bytes of signature to hash", n, len(b))
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}
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return nil
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}
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type ECDSASignature struct {
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R, S *big.Int
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}
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func (r *ecdsaAlgorithm) Sign(rand io.Reader, p crypto.PrivateKey, sig []byte) ([]byte, error) {
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defer r.Reset()
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if err := r.setSig(sig); err != nil {
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return nil, err
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}
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ecdsaK, ok := p.(*ecdsa.PrivateKey)
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if !ok {
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return nil, errors.New("crypto.PrivateKey is not *ecdsa.PrivateKey")
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}
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R, S, err := ecdsa.Sign(rand, ecdsaK, r.Sum(nil))
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if err != nil {
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return nil, err
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}
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signature := ECDSASignature{R: R, S: S}
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bytes, err := asn1.Marshal(signature)
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return bytes, err
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}
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func (r *ecdsaAlgorithm) Verify(pub crypto.PublicKey, toHash, signature []byte) error {
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defer r.Reset()
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ecdsaK, ok := pub.(*ecdsa.PublicKey)
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if !ok {
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return errors.New("crypto.PublicKey is not *ecdsa.PublicKey")
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}
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if err := r.setSig(toHash); err != nil {
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return err
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}
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sig := new(ECDSASignature)
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_, err := asn1.Unmarshal(signature, sig)
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if err != nil {
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return err
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}
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if ecdsa.Verify(ecdsaK, r.Sum(nil), sig.R, sig.S) {
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return nil
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} else {
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return errors.New("Invalid signature")
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}
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}
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func (r *ecdsaAlgorithm) String() string {
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return fmt.Sprintf("%s-%s", ecdsaPrefix, hashToDef[r.kind].name)
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}
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var _ macer = &blakeMacAlgorithm{}
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type blakeMacAlgorithm struct {
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fn func(key []byte) (hash.Hash, error)
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kind crypto.Hash
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}
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func (r *blakeMacAlgorithm) Sign(sig, key []byte) ([]byte, error) {
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hs, err := r.fn(key)
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if err != nil {
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return nil, err
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}
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if err = setSig(hs, sig); err != nil {
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return nil, err
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}
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return hs.Sum(nil), nil
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}
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func (r *blakeMacAlgorithm) Equal(sig, actualMAC, key []byte) (bool, error) {
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|
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hs, err := r.fn(key)
|
||
|
|
if err != nil {
|
||
|
|
return false, err
|
||
|
|
}
|
||
|
|
defer hs.Reset()
|
||
|
|
err = setSig(hs, sig)
|
||
|
|
if err != nil {
|
||
|
|
return false, err
|
||
|
|
}
|
||
|
|
expected := hs.Sum(nil)
|
||
|
|
return subtle.ConstantTimeCompare(actualMAC, expected) == 1, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (r *blakeMacAlgorithm) String() string {
|
||
|
|
return fmt.Sprintf("%s", hashToDef[r.kind].name)
|
||
|
|
}
|
||
|
|
|
||
|
|
func setSig(a hash.Hash, b []byte) error {
|
||
|
|
n, err := a.Write(b)
|
||
|
|
if err != nil {
|
||
|
|
a.Reset()
|
||
|
|
return err
|
||
|
|
} else if n != len(b) {
|
||
|
|
a.Reset()
|
||
|
|
return fmt.Errorf("could only write %d of %d bytes of signature to hash", n, len(b))
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// IsSupportedHttpSigAlgorithm returns true if the string is supported by this
|
||
|
|
// library, is not a hash known to be weak, and is supported by the hardware.
|
||
|
|
func IsSupportedHttpSigAlgorithm(algo string) bool {
|
||
|
|
a, err := isAvailable(algo)
|
||
|
|
return a && err == nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// isAvailable is an internally public function
|
||
|
|
func isAvailable(algo string) (bool, error) {
|
||
|
|
c, ok := stringToHash[algo]
|
||
|
|
if !ok {
|
||
|
|
return false, fmt.Errorf("no match for %q", algo)
|
||
|
|
}
|
||
|
|
if isForbiddenHash(c) {
|
||
|
|
return false, fmt.Errorf("forbidden hash type in %q", algo)
|
||
|
|
}
|
||
|
|
return c.Available(), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func newAlgorithmConstructor(algo string) (fn func(k []byte) (hash.Hash, error), c crypto.Hash, e error) {
|
||
|
|
ok := false
|
||
|
|
c, ok = stringToHash[algo]
|
||
|
|
if !ok {
|
||
|
|
e = fmt.Errorf("no match for %q", algo)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
if isForbiddenHash(c) {
|
||
|
|
e = fmt.Errorf("forbidden hash type in %q", algo)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
algoDef, ok := hashToDef[c]
|
||
|
|
if !ok {
|
||
|
|
e = fmt.Errorf("have crypto.Hash %v but no definition", c)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
fn = func(key []byte) (hash.Hash, error) {
|
||
|
|
h, err := algoDef.new(key)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
return h, nil
|
||
|
|
}
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
func newAlgorithm(algo string, key []byte) (hash.Hash, crypto.Hash, error) {
|
||
|
|
fn, c, err := newAlgorithmConstructor(algo)
|
||
|
|
if err != nil {
|
||
|
|
return nil, c, err
|
||
|
|
}
|
||
|
|
h, err := fn(key)
|
||
|
|
return h, c, err
|
||
|
|
}
|
||
|
|
|
||
|
|
func signerFromSSHSigner(sshSigner ssh.Signer, s string) (signer, error) {
|
||
|
|
switch {
|
||
|
|
case strings.HasPrefix(s, rsaPrefix):
|
||
|
|
return &rsaAlgorithm{
|
||
|
|
sshSigner: sshSigner,
|
||
|
|
}, nil
|
||
|
|
case strings.HasPrefix(s, ed25519Prefix):
|
||
|
|
return &ed25519Algorithm{
|
||
|
|
sshSigner: sshSigner,
|
||
|
|
}, nil
|
||
|
|
default:
|
||
|
|
return nil, fmt.Errorf("no signer matching %q", s)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// signerFromString is an internally public method constructor
|
||
|
|
func signerFromString(s string) (signer, error) {
|
||
|
|
s = strings.ToLower(s)
|
||
|
|
isEcdsa := false
|
||
|
|
isEd25519 := false
|
||
|
|
var algo string = ""
|
||
|
|
if strings.HasPrefix(s, ecdsaPrefix) {
|
||
|
|
algo = strings.TrimPrefix(s, ecdsaPrefix+"-")
|
||
|
|
isEcdsa = true
|
||
|
|
} else if strings.HasPrefix(s, rsaPrefix) {
|
||
|
|
algo = strings.TrimPrefix(s, rsaPrefix+"-")
|
||
|
|
} else if strings.HasPrefix(s, ed25519Prefix) {
|
||
|
|
isEd25519 = true
|
||
|
|
algo = "sha512"
|
||
|
|
} else {
|
||
|
|
return nil, fmt.Errorf("no signer matching %q", s)
|
||
|
|
}
|
||
|
|
hash, cHash, err := newAlgorithm(algo, nil)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
if isEd25519 {
|
||
|
|
return &ed25519Algorithm{}, nil
|
||
|
|
}
|
||
|
|
if isEcdsa {
|
||
|
|
return &ecdsaAlgorithm{
|
||
|
|
Hash: hash,
|
||
|
|
kind: cHash,
|
||
|
|
}, nil
|
||
|
|
}
|
||
|
|
return &rsaAlgorithm{
|
||
|
|
Hash: hash,
|
||
|
|
kind: cHash,
|
||
|
|
}, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// macerFromString is an internally public method constructor
|
||
|
|
func macerFromString(s string) (macer, error) {
|
||
|
|
s = strings.ToLower(s)
|
||
|
|
if strings.HasPrefix(s, hmacPrefix) {
|
||
|
|
algo := strings.TrimPrefix(s, hmacPrefix+"-")
|
||
|
|
hashFn, cHash, err := newAlgorithmConstructor(algo)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
// Ensure below does not panic
|
||
|
|
_, err = hashFn(nil)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
return &hmacAlgorithm{
|
||
|
|
fn: func(key []byte) (hash.Hash, error) {
|
||
|
|
return hmac.New(func() hash.Hash {
|
||
|
|
h, e := hashFn(nil)
|
||
|
|
if e != nil {
|
||
|
|
panic(e)
|
||
|
|
}
|
||
|
|
return h
|
||
|
|
}, key), nil
|
||
|
|
},
|
||
|
|
kind: cHash,
|
||
|
|
}, nil
|
||
|
|
} else if bl, ok := stringToHash[s]; ok && blake2Algorithms[bl] {
|
||
|
|
hashFn, cHash, err := newAlgorithmConstructor(s)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
return &blakeMacAlgorithm{
|
||
|
|
fn: hashFn,
|
||
|
|
kind: cHash,
|
||
|
|
}, nil
|
||
|
|
} else {
|
||
|
|
return nil, fmt.Errorf("no MACer matching %q", s)
|
||
|
|
}
|
||
|
|
}
|