From f6c92c5e2d87ab1334648b0d1293771de7aae4a5 Mon Sep 17 00:00:00 2001
From: Rutger Broekhoff
Date: Sat, 30 Dec 2023 14:00:34 +0100
Subject: Implement git-lfs-authenticate

---
 vendor/github.com/golang-jwt/jwt/v5/hmac.go | 104 ++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 vendor/github.com/golang-jwt/jwt/v5/hmac.go

(limited to 'vendor/github.com/golang-jwt/jwt/v5/hmac.go')

diff --git a/vendor/github.com/golang-jwt/jwt/v5/hmac.go b/vendor/github.com/golang-jwt/jwt/v5/hmac.go
new file mode 100644
index 0000000..96c6272
--- /dev/null
+++ b/vendor/github.com/golang-jwt/jwt/v5/hmac.go
@@ -0,0 +1,104 @@
+package jwt
+
+import (
+	"crypto"
+	"crypto/hmac"
+	"errors"
+)
+
+// SigningMethodHMAC implements the HMAC-SHA family of signing methods.
+// Expects key type of []byte for both signing and validation
+type SigningMethodHMAC struct {
+	Name string
+	Hash crypto.Hash
+}
+
+// Specific instances for HS256 and company
+var (
+	SigningMethodHS256  *SigningMethodHMAC
+	SigningMethodHS384  *SigningMethodHMAC
+	SigningMethodHS512  *SigningMethodHMAC
+	ErrSignatureInvalid = errors.New("signature is invalid")
+)
+
+func init() {
+	// HS256
+	SigningMethodHS256 = &SigningMethodHMAC{"HS256", crypto.SHA256}
+	RegisterSigningMethod(SigningMethodHS256.Alg(), func() SigningMethod {
+		return SigningMethodHS256
+	})
+
+	// HS384
+	SigningMethodHS384 = &SigningMethodHMAC{"HS384", crypto.SHA384}
+	RegisterSigningMethod(SigningMethodHS384.Alg(), func() SigningMethod {
+		return SigningMethodHS384
+	})
+
+	// HS512
+	SigningMethodHS512 = &SigningMethodHMAC{"HS512", crypto.SHA512}
+	RegisterSigningMethod(SigningMethodHS512.Alg(), func() SigningMethod {
+		return SigningMethodHS512
+	})
+}
+
+func (m *SigningMethodHMAC) Alg() string {
+	return m.Name
+}
+
+// Verify implements token verification for the SigningMethod. Returns nil if
+// the signature is valid. Key must be []byte.
+//
+// Note it is not advised to provide a []byte which was converted from a 'human
+// readable' string using a subset of ASCII characters. To maximize entropy, you
+// should ideally be providing a []byte key which was produced from a
+// cryptographically random source, e.g. crypto/rand. Additional information
+// about this, and why we intentionally are not supporting string as a key can
+// be found on our usage guide
+// https://golang-jwt.github.io/jwt/usage/signing_methods/#signing-methods-and-key-types.
+func (m *SigningMethodHMAC) Verify(signingString string, sig []byte, key interface{}) error {
+	// Verify the key is the right type
+	keyBytes, ok := key.([]byte)
+	if !ok {
+		return newError("HMAC verify expects []byte", ErrInvalidKeyType)
+	}
+
+	// Can we use the specified hashing method?
+	if !m.Hash.Available() {
+		return ErrHashUnavailable
+	}
+
+	// This signing method is symmetric, so we validate the signature
+	// by reproducing the signature from the signing string and key, then
+	// comparing that against the provided signature.
+	hasher := hmac.New(m.Hash.New, keyBytes)
+	hasher.Write([]byte(signingString))
+	if !hmac.Equal(sig, hasher.Sum(nil)) {
+		return ErrSignatureInvalid
+	}
+
+	// No validation errors.  Signature is good.
+	return nil
+}
+
+// Sign implements token signing for the SigningMethod. Key must be []byte.
+//
+// Note it is not advised to provide a []byte which was converted from a 'human
+// readable' string using a subset of ASCII characters. To maximize entropy, you
+// should ideally be providing a []byte key which was produced from a
+// cryptographically random source, e.g. crypto/rand. Additional information
+// about this, and why we intentionally are not supporting string as a key can
+// be found on our usage guide https://golang-jwt.github.io/jwt/usage/signing_methods/.
+func (m *SigningMethodHMAC) Sign(signingString string, key interface{}) ([]byte, error) {
+	if keyBytes, ok := key.([]byte); ok {
+		if !m.Hash.Available() {
+			return nil, newError("HMAC sign expects []byte", ErrInvalidKeyType)
+		}
+
+		hasher := hmac.New(m.Hash.New, keyBytes)
+		hasher.Write([]byte(signingString))
+
+		return hasher.Sum(nil), nil
+	}
+
+	return nil, ErrInvalidKeyType
+}
-- 
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