v0.1.0 (#17)

pkg/auth/jwt.go

@@ -0,0 +1,113 @@
+package auth
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/jackc/pgx/v5/pgtype"
+
+	"git.omukk.dev/wrenn/wrenn/pkg/id"
+)
+
+const jwtExpiry = 6 * time.Hour
+const hostJWTExpiry = 7 * 24 * time.Hour           // 7 days; host refreshes via refresh token
+const HostRefreshTokenExpiry = 60 * 24 * time.Hour // 60 days; exported for service layer
+
+// Claims are the JWT payload for user tokens.
+type Claims struct {
+	Type    string `json:"typ,omitempty"` // empty for user tokens; used to reject host tokens
+	TeamID  string `json:"team_id"`
+	Role    string `json:"role"` // owner, admin, or member within TeamID
+	Email   string `json:"email"`
+	Name    string `json:"name"`
+	IsAdmin bool   `json:"is_admin,omitempty"` // platform-level admin flag
+	jwt.RegisteredClaims
+}
+
+// SignJWT signs a new 6-hour JWT for the given user.
+func SignJWT(secret []byte, userID, teamID pgtype.UUID, email, name, role string, isAdmin bool) (string, error) {
+	now := time.Now()
+	claims := Claims{
+		TeamID:  id.FormatTeamID(teamID),
+		Role:    role,
+		Email:   email,
+		Name:    name,
+		IsAdmin: isAdmin,
+		RegisteredClaims: jwt.RegisteredClaims{
+			Subject:   id.FormatUserID(userID),
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(now.Add(jwtExpiry)),
+		},
+	}
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString(secret)
+}
+
+// VerifyJWT parses and validates a user JWT, returning the claims on success.
+// Rejects host JWTs (which carry a "typ" claim) to prevent cross-token confusion.
+func VerifyJWT(secret []byte, tokenStr string) (Claims, error) {
+	token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(t *jwt.Token) (any, error) {
+		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
+		}
+		return secret, nil
+	})
+	if err != nil {
+		return Claims{}, fmt.Errorf("invalid token: %w", err)
+	}
+	c, ok := token.Claims.(*Claims)
+	if !ok || !token.Valid {
+		return Claims{}, fmt.Errorf("invalid token claims")
+	}
+	if c.Type == "host" {
+		return Claims{}, fmt.Errorf("invalid token: host token cannot be used as user token")
+	}
+	return *c, nil
+}
+
+// HostClaims are the JWT payload for host agent tokens.
+type HostClaims struct {
+	Type   string `json:"typ"` // always "host"
+	HostID string `json:"host_id"`
+	jwt.RegisteredClaims
+}
+
+// SignHostJWT signs a long-lived (7-day) JWT for a registered host agent.
+func SignHostJWT(secret []byte, hostID pgtype.UUID) (string, error) {
+	formatted := id.FormatHostID(hostID)
+	now := time.Now()
+	claims := HostClaims{
+		Type:   "host",
+		HostID: formatted,
+		RegisteredClaims: jwt.RegisteredClaims{
+			Subject:   formatted,
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(now.Add(hostJWTExpiry)),
+		},
+	}
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString(secret)
+}
+
+// VerifyHostJWT parses and validates a host JWT, returning the claims on success.
+// It rejects user JWTs by checking the "typ" claim.
+func VerifyHostJWT(secret []byte, tokenStr string) (HostClaims, error) {
+	token, err := jwt.ParseWithClaims(tokenStr, &HostClaims{}, func(t *jwt.Token) (any, error) {
+		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
+		}
+		return secret, nil
+	})
+	if err != nil {
+		return HostClaims{}, fmt.Errorf("invalid token: %w", err)
+	}
+	c, ok := token.Claims.(*HostClaims)
+	if !ok || !token.Valid {
+		return HostClaims{}, fmt.Errorf("invalid token claims")
+	}
+	if c.Type != "host" {
+		return HostClaims{}, fmt.Errorf("invalid token type: expected host")
+	}
+	return *c, nil
+}