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package oidc
import (
"errors"
"fmt"
"time"
"github.com/jonboulle/clockwork"
"github.com/coreos/go-oidc/jose"
"github.com/coreos/go-oidc/key"
)
func VerifySignature(jwt jose.JWT, keys []key.PublicKey) (bool, error) {
jwtBytes := []byte(jwt.Data())
for _, k := range keys {
v, err := k.Verifier()
if err != nil {
return false, err
}
if v.Verify(jwt.Signature, jwtBytes) == nil {
return true, nil
}
}
return false, nil
}
// containsString returns true if the given string(needle) is found
// in the string array(haystack).
func containsString(needle string, haystack []string) bool {
for _, v := range haystack {
if v == needle {
return true
}
}
return false
}
// Verify claims in accordance with OIDC spec
// http://openid.net/specs/openid-connect-basic-1_0.html#IDTokenValidation
func VerifyClaims(jwt jose.JWT, issuer, clientID string) error {
now := time.Now().UTC()
claims, err := jwt.Claims()
if err != nil {
return err
}
ident, err := IdentityFromClaims(claims)
if err != nil {
return err
}
if ident.ExpiresAt.Before(now) {
return errors.New("token is expired")
}
// iss REQUIRED. Issuer Identifier for the Issuer of the response.
// The iss value is a case sensitive URL using the https scheme that contains scheme,
// host, and optionally, port number and path components and no query or fragment components.
if iss, exists := claims["iss"].(string); exists {
if !urlEqual(iss, issuer) {
return fmt.Errorf("invalid claim value: 'iss'. expected=%s, found=%s.", issuer, iss)
}
} else {
return errors.New("missing claim: 'iss'")
}
// iat REQUIRED. Time at which the JWT was issued.
// Its value is a JSON number representing the number of seconds from 1970-01-01T0:0:0Z
// as measured in UTC until the date/time.
if _, exists := claims["iat"].(float64); !exists {
return errors.New("missing claim: 'iat'")
}
// aud REQUIRED. Audience(s) that this ID Token is intended for.
// It MUST contain the OAuth 2.0 client_id of the Relying Party as an audience value.
// It MAY also contain identifiers for other audiences. In the general case, the aud
// value is an array of case sensitive strings. In the common special case when there
// is one audience, the aud value MAY be a single case sensitive string.
if aud, ok, err := claims.StringClaim("aud"); err == nil && ok {
if aud != clientID {
return fmt.Errorf("invalid claims, 'aud' claim and 'client_id' do not match, aud=%s, client_id=%s", aud, clientID)
}
} else if aud, ok, err := claims.StringsClaim("aud"); err == nil && ok {
if !containsString(clientID, aud) {
return fmt.Errorf("invalid claims, cannot find 'client_id' in 'aud' claim, aud=%v, client_id=%s", aud, clientID)
}
} else {
return errors.New("invalid claim value: 'aud' is required, and should be either string or string array")
}
return nil
}
// VerifyClientClaims verifies all the required claims are valid for a "client credentials" JWT.
// Returns the client ID if valid, or an error if invalid.
func VerifyClientClaims(jwt jose.JWT, issuer string) (string, error) {
claims, err := jwt.Claims()
if err != nil {
return "", fmt.Errorf("failed to parse JWT claims: %v", err)
}
iss, ok, err := claims.StringClaim("iss")
if err != nil {
return "", fmt.Errorf("failed to parse 'iss' claim: %v", err)
} else if !ok {
return "", errors.New("missing required 'iss' claim")
} else if !urlEqual(iss, issuer) {
return "", fmt.Errorf("'iss' claim does not match expected issuer, iss=%s", iss)
}
sub, ok, err := claims.StringClaim("sub")
if err != nil {
return "", fmt.Errorf("failed to parse 'sub' claim: %v", err)
} else if !ok {
return "", errors.New("missing required 'sub' claim")
}
if aud, ok, err := claims.StringClaim("aud"); err == nil && ok {
if aud != sub {
return "", fmt.Errorf("invalid claims, 'aud' claim and 'sub' claim do not match, aud=%s, sub=%s", aud, sub)
}
} else if aud, ok, err := claims.StringsClaim("aud"); err == nil && ok {
if !containsString(sub, aud) {
return "", fmt.Errorf("invalid claims, cannot find 'sud' in 'aud' claim, aud=%v, sub=%s", aud, sub)
}
} else {
return "", errors.New("invalid claim value: 'aud' is required, and should be either string or string array")
}
now := time.Now().UTC()
exp, ok, err := claims.TimeClaim("exp")
if err != nil {
return "", fmt.Errorf("failed to parse 'exp' claim: %v", err)
} else if !ok {
return "", errors.New("missing required 'exp' claim")
} else if exp.Before(now) {
return "", fmt.Errorf("token already expired at: %v", exp)
}
return sub, nil
}
type JWTVerifier struct {
issuer string
clientID string
syncFunc func() error
keysFunc func() []key.PublicKey
clock clockwork.Clock
}
func NewJWTVerifier(issuer, clientID string, syncFunc func() error, keysFunc func() []key.PublicKey) JWTVerifier {
return JWTVerifier{
issuer: issuer,
clientID: clientID,
syncFunc: syncFunc,
keysFunc: keysFunc,
clock: clockwork.NewRealClock(),
}
}
func (v *JWTVerifier) Verify(jwt jose.JWT) error {
ok, err := VerifySignature(jwt, v.keysFunc())
if ok {
goto SignatureVerified
} else if err != nil {
return fmt.Errorf("oidc: JWT signature verification failed: %v", err)
}
if err = v.syncFunc(); err != nil {
return fmt.Errorf("oidc: failed syncing KeySet: %v", err)
}
ok, err = VerifySignature(jwt, v.keysFunc())
if err != nil {
return fmt.Errorf("oidc: JWT signature verification failed: %v", err)
} else if !ok {
return errors.New("oidc: unable to verify JWT signature: no matching keys")
}
SignatureVerified:
if err := VerifyClaims(jwt, v.issuer, v.clientID); err != nil {
return fmt.Errorf("oidc: JWT claims invalid: %v", err)
}
return nil
}
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