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fix(yurthub): reject unauthenticated requests on insecure proxy port #2783

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fix(yurthub): reject unauthenticated requests on insecure proxy port #2783

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31 changes: 31 additions & 0 deletions pkg/yurthub/proxy/util/util.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ import (
apirequest "k8s.io/apiserver/pkg/endpoints/request"
"k8s.io/klog/v2"

"github.com/openyurtio/openyurt/pkg/projectinfo"
"github.com/openyurtio/openyurt/pkg/yurthub/filter"
"github.com/openyurtio/openyurt/pkg/yurthub/metrics"
"github.com/openyurtio/openyurt/pkg/yurthub/tenant"
Expand Down Expand Up @@ -457,3 +458,33 @@ func IsSubjectAccessReviewCreateGetRequest(req *http.Request) bool {
info.Resource == "subjectaccessreviews" &&
(info.Verb == "create" || info.Verb == "get")
}

// WithRequireAuthorization rejects any request that does not carry an Authorization
// header with a 401 Unauthorized response, unless the request originates from
// YurtHub itself (identified by its well-known User-Agent prefixes).
//
// This middleware MUST be applied to the insecure (plain-HTTP) proxy port.
// Without it, RemoteProxy.RoundTrip forwards credential-free requests using
// YurtHub's own node client certificate, effectively lending the node identity
// (system:node:<node>) to any pod that can reach the dummy interface IP
// (169.254.2.1:10261). See: https://github.com/openyurtio/openyurt/issues/2782
func WithRequireAuthorization(handler http.Handler, nodeName string) http.Handler {
multiplexerUserAgent := util.MultiplexerProxyClientUserAgentPrefix + nodeName
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
// Allow requests from YurtHub itself: the internal multiplexer client
// and the shared-informer clients both omit Authorization headers but
// carry well-known User-Agent values. They must not be blocked.
ua := req.UserAgent()
if ua == multiplexerUserAgent || strings.HasPrefix(ua, projectinfo.GetHubName()) {
handler.ServeHTTP(w, req)
return
}

if strings.TrimSpace(req.Header.Get("Authorization")) == "" {
klog.V(2).Infof("rejected unauthenticated request %s: missing Authorization header on insecure proxy port", util.ReqString(req))
http.Error(w, "Unauthorized: requests to the YurtHub proxy must include an Authorization header", http.StatusUnauthorized)
return
}
handler.ServeHTTP(w, req)
})
}
14 changes: 7 additions & 7 deletions pkg/yurthub/server/server.go
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@ import (
"github.com/openyurtio/openyurt/pkg/yurthub/healthchecker"
ota "github.com/openyurtio/openyurt/pkg/yurthub/otaupdate"
otautil "github.com/openyurtio/openyurt/pkg/yurthub/otaupdate/util"
proxyutil "github.com/openyurtio/openyurt/pkg/yurthub/proxy/util"
)

// RunYurtHubServers is used to start up all servers for yurthub
Expand All @@ -53,13 +54,12 @@ func RunYurtHubServers(cfg *config.YurtHubConfiguration,

// start yurthub proxy servers for forwarding requests to cloud kube-apiserver
if cfg.YurtHubProxyServerServing != nil {
if err := cfg.YurtHubProxyServerServing.Serve(proxyHandler, 0, stopCh); err != nil {
return err
}
}

if cfg.YurtHubDummyProxyServerServing != nil {
if err := cfg.YurtHubDummyProxyServerServing.Serve(proxyHandler, 0, stopCh); err != nil {
// Wrap the proxy handler so that requests arriving on the plain-HTTP port
// without an Authorization header are rejected with 401 instead of being
// forwarded using YurtHub's own node client certificate.
// See: https://github.com/openyurtio/openyurt/issues/2782
insecureProxyHandler := proxyutil.WithRequireAuthorization(proxyHandler, cfg.NodeName)
if err := cfg.YurtHubProxyServerServing.Serve(insecureProxyHandler, 0, stopCh); err != nil {
return err
}
}
Expand Down