47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
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package authjwt
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import (
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"crypto/ecdsa"
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"crypto/x509"
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"encoding/pem"
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"fmt"
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"github.com/golang-jwt/jwt/v5"
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)
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var _ Verifier = (*ecPublicVerifier)(nil)
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type ecPublicVerifier struct{ public *ecdsa.PublicKey }
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// NewECPublicKeyVerifier returns a Verifier backed by an ECDSA public key.
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// Use this in services that verify tokens but never issue them.
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func NewECPublicKeyVerifier(publicKey *ecdsa.PublicKey) Verifier {
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return &ecPublicVerifier{public: publicKey}
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}
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// NewECPublicKeyVerifierFromPEM parses a PKIX PEM-encoded ECDSA public key.
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func NewECPublicKeyVerifierFromPEM(pemKey []byte) (Verifier, error) {
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block, _ := pem.Decode(pemKey)
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if block == nil {
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return nil, fmt.Errorf("no PEM block found")
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}
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pub, err := x509.ParsePKIXPublicKey(block.Bytes)
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if err != nil {
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return nil, fmt.Errorf("parse EC public key: %w", err)
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}
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ecPub, ok := pub.(*ecdsa.PublicKey)
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if !ok {
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return nil, fmt.Errorf("PEM key is not an EC public key")
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}
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return NewECPublicKeyVerifier(ecPub), nil
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}
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func (v *ecPublicVerifier) Verify(tokenString string) (*jwt.Token, error) {
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return jwt.Parse(tokenString, func(t *jwt.Token) (any, error) {
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if _, ok := t.Method.(*jwt.SigningMethodECDSA); !ok {
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return nil, fmt.Errorf("unexpected signing method %q", t.Header["alg"])
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}
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return v.public, nil
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}, jwt.WithJSONNumber())
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}
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