feat(auth): accept clock skew for token validation

internal/auth/thirdparty/authenticator.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"net/http"
 	"strings"
+	"time"
 
 	"forge.cadoles.com/Cadoles/emissary/internal/auth"
 	"forge.cadoles.com/Cadoles/emissary/internal/jwk"
@@ -11,9 +12,12 @@ import (
 	"gitlab.com/wpetit/goweb/logger"
 )
 
+const DefaultAcceptableSkew = 5 * time.Minute
+
 type Authenticator struct {
-	keys   jwk.Set
-	issuer string
+	keys           jwk.Set
+	issuer         string
+	acceptableSkew time.Duration
 }
 
 // Authenticate implements auth.Authenticator.
@@ -30,7 +34,7 @@ func (a *Authenticator) Authenticate(ctx context.Context, r *http.Request) (auth
 		return nil, errors.WithStack(auth.ErrUnauthenticated)
 	}
 
-	token, err := parseToken(ctx, a.keys, a.issuer, rawToken)
+	token, err := parseToken(ctx, a.keys, a.issuer, rawToken, a.acceptableSkew)
 	if err != nil {
 		return nil, errors.WithStack(err)
 	}
@@ -57,10 +61,11 @@ func (a *Authenticator) Authenticate(ctx context.Context, r *http.Request) (auth
 	return user, nil
 }
 
-func NewAuthenticator(keys jwk.Set, issuer string) *Authenticator {
+func NewAuthenticator(keys jwk.Set, issuer string, acceptableSkew time.Duration) *Authenticator {
 	return &Authenticator{
-		keys:   keys,
-		issuer: issuer,
+		keys:           keys,
+		issuer:         issuer,
+		acceptableSkew: acceptableSkew,
 	}
 }
 

internal/auth/thirdparty/jwt.go

@@ -13,12 +13,13 @@ import (
 
 const keyRole = "role"
 
-func parseToken(ctx context.Context, keys jwk.Set, issuer string, rawToken string) (jwt.Token, error) {
+func parseToken(ctx context.Context, keys jwk.Set, issuer string, rawToken string, acceptableSkew time.Duration) (jwt.Token, error) {
 	token, err := jwt.Parse(
 		[]byte(rawToken),
 		jwt.WithKeySet(keys, jws.WithRequireKid(false)),
 		jwt.WithIssuer(issuer),
 		jwt.WithValidate(true),
+		jwt.WithAcceptableSkew(acceptableSkew),
 	)
 	if err != nil {
 		return nil, errors.WithStack(err)