Files
warmbly/internal/api/middleware/internal_auth.go
T

105 lines
3.2 KiB
Go

package middleware
import (
"crypto/subtle"
"net/http"
"os"
"strings"
"sync"
"github.com/gin-gonic/gin"
)
// InternalAuthMiddleware protects backend-to-backend endpoints (the worker DEK
// fetch is the first user) with a static bearer token sourced from the
// INTERNAL_API_TOKEN env var. Constant-time compare to defeat timing oracles.
//
// This is a deliberately simple primitive — workers and backend share one
// secret out-of-band (env var in both processes). Task #9 will replace this
// with per-worker JWTs minted at registration time.
//
// If INTERNAL_API_TOKEN is unset, every request is rejected — fail closed.
func (h *Handler) InternalAuthMiddleware() gin.HandlerFunc {
return internalAuth
}
var (
internalTokenOnce sync.Once
internalToken []byte
)
func loadInternalToken() {
if v := os.Getenv("INTERNAL_API_TOKEN"); v != "" {
internalToken = []byte(v)
}
}
func internalAuth(c *gin.Context) {
internalTokenOnce.Do(loadInternalToken)
if len(internalToken) == 0 {
c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "internal auth not configured"})
return
}
header := c.GetHeader("Authorization")
if !strings.HasPrefix(header, "Bearer ") {
c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "missing bearer token"})
return
}
provided := []byte(strings.TrimPrefix(header, "Bearer "))
if subtle.ConstantTimeCompare(provided, internalToken) != 1 {
c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "invalid bearer token"})
return
}
c.Next()
}
// NodeBrokerAuthMiddleware protects the two endpoints that perform a
// privileged operation on a caller's behalf: opening a sealed data key, and
// signing a blob operation.
//
// They are a step up from the rest of the internal API, which only moves
// records around. A caller here gets plaintext key material and a URL into the
// object store, so the token that opens them should not have to be the same
// one the tracking and forms services carry: those are internet-facing, and
// widening what their credential is worth is the whole risk.
//
// NODE_BROKER_TOKEN is that separate credential. It falls back to
// INTERNAL_API_TOKEN when unset, so an existing single-token deployment keeps
// working, and a split deployment can hand nodes something the edge services
// never see.
func (h *Handler) NodeBrokerAuthMiddleware() gin.HandlerFunc {
return nodeBrokerAuth
}
var (
brokerTokenOnce sync.Once
brokerToken []byte
)
func loadBrokerToken() {
if v := os.Getenv("NODE_BROKER_TOKEN"); v != "" {
brokerToken = []byte(v)
return
}
brokerToken = []byte(os.Getenv("INTERNAL_API_TOKEN"))
}
func nodeBrokerAuth(c *gin.Context) {
brokerTokenOnce.Do(loadBrokerToken)
if len(brokerToken) == 0 {
c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "internal auth not configured"})
return
}
header := c.GetHeader("Authorization")
if !strings.HasPrefix(header, "Bearer ") {
c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "missing bearer token"})
return
}
provided := []byte(strings.TrimPrefix(header, "Bearer "))
if subtle.ConstantTimeCompare(provided, brokerToken) != 1 {
c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "invalid bearer token"})
return
}
c.Next()
}