R89: normalize excluded-url paths; apply defaults to pooled HTTP clients

Two verified defects from R89 scout round:

1. Excluded-URL dot-segment traversal widening (P1, auth bypass).
   shouldBypassAuth passes req.URL.Path raw (middleware.go:54); Go's server
   leaves '..' in URL.Path (url.ParseRequestURI does not normalize), so an
   exclusion for /public also matched /public/../admin, letting a real
   sibling (/admin) reach the backend unauthenticated. pathExcluded now
   path.Clean()s the request path ('.' -> '' to preserve root semantics)
   before boundary matching. Regression TestR89ExcludedPathDotTraversal
   fails on old (all 4 traversal cases wrongly excluded), passes on new.

2. Pooled HTTP client had no zero-value defaults (P2, unbounded stall).
   CreateHTTPClient applies defaults; CreatePooledHTTPClient and
   GetOrCreateTransport did not, so a partial config yielded Timeout=0 and
   ResponseHeaderTimeout=0 (a hanging upstream stalls forever). Extracted
   applyHTTPClientDefaults (single source of truth) and applied it in all
   three construction paths; pool cache key now reflects normalized values.
   Regression TestR89PooledClientAppliesDefaults fails on old, passes on new.

R89 clean/declined: session max-age IS absolute-and-enforced-every-request
(verified, review_r68 already locks it); AllowedUserDomains fail-closed (P2
'*' not a wildcard, P3 TrimSpace — declined as config-scoped).

http_client_factory.go

@@ -138,10 +138,13 @@ func (f *HTTPClientFactory) ValidateHTTPClientConfig(config *HTTPClientConfig) e
 	return nil
 }
 
-// CreateHTTPClient creates an HTTP client with the given configuration
+// applyHTTPClientDefaults fills zero-valued fields in cfg with the standard
-// Validates configuration parameters before creating the client
+// conservative defaults so that a partially-populated config never yields an
-func (f *HTTPClientFactory) CreateHTTPClient(config HTTPClientConfig) *http.Client {
+// unbounded HTTP client (zero overall Timeout or ResponseHeaderTimeout would make
-	// Set defaults for zero values before validation
+// a stalled upstream hang forever). All construction paths MUST converge on this
+// helper so behavior is identical: CreateHTTPClient and the shared transport
+// pool (CreatePooledHTTPClient / GetOrCreateTransport).
+func applyHTTPClientDefaults(config *HTTPClientConfig) {
 	if config.Timeout == 0 {
 		config.Timeout = 30 * time.Second
 	}
@@ -178,6 +181,13 @@ func (f *HTTPClientFactory) CreateHTTPClient(config HTTPClientConfig) *http.Clie
 	if config.ReadBufferSize == 0 {
 		config.ReadBufferSize = 4096
 	}
+}
+
+// CreateHTTPClient creates an HTTP client with the given configuration
+// Validates configuration parameters before creating the client
+func (f *HTTPClientFactory) CreateHTTPClient(config HTTPClientConfig) *http.Client {
+	// Set defaults for zero values before validation
+	applyHTTPClientDefaults(&config)
 
 	// Validate configuration - only fail on critical errors
 	if err := f.ValidateHTTPClientConfig(&config); err != nil {

http_client_pool.go

@@ -58,6 +58,12 @@ func GetGlobalTransportPool() *SharedTransportPool {
 
 // GetOrCreateTransport gets or creates a shared transport with the given config
 func (p *SharedTransportPool) GetOrCreateTransport(config HTTPClientConfig) *http.Transport {
+	// Apply the same zero-value defaults as CreateHTTPClient so a partially
+	// populated config never yields an unbounded client/transport, and so the
+	// pool cache key reflects normalized values (configKey). Bounded here,
+	// before the client-count gate, so both the gate and the key see
+	// normalized timeouts.
+	applyHTTPClientDefaults(&config)
 	// SECURITY FIX: Check client limit before creating new transport.
 	if atomic.LoadInt32(&p.clientCount) >= p.maxClients {
 		// At the client limit: only reuse a transport that was built for the
@@ -282,6 +288,9 @@ func (p *SharedTransportPool) Cleanup() {
 
 // CreatePooledHTTPClient creates an HTTP client using the shared transport pool
 func CreatePooledHTTPClient(config HTTPClientConfig) *http.Client {
+	// Apply the same zero-value defaults as CreateHTTPClient so a partially
+	// populated config still gets a bounded overall request Timeout.
+	applyHTTPClientDefaults(&config)
 	pool := GetGlobalTransportPool()
 	transport := pool.GetOrCreateTransport(config)
 

review_r89_test.go

@@ -0,0 +1,64 @@
+package traefikoidc
+
+import (
+	"net/http"
+	"testing"
+)
+
+// R89 regression: pathExcluded matched the RAW request path as a string
+// prefix. Go's server leaves ".." in req.URL.Path (url.ParseRequestURI does
+// not normalize dot segments), so an exclusion for "/public" also matched
+// "/public/../admin", letting a dot-segment traversal reach a sibling
+// resource (e.g. /admin) unauthenticated. The matcher must normalize the
+// request path (path.Clean) before the boundary comparison so traversal
+// cannot widen an exclusion into an authentication bypass.
+func TestR89ExcludedPathDotTraversal(t *testing.T) {
+	// Exact-matching and legitimate-subtree exclusions must be preserved.
+	if !pathExcluded("/public", "/public") {
+		t.Error("exact match should be excluded")
+	}
+	if !pathExcluded("/public/page", "/public") {
+		t.Error("sub-path should still be excluded")
+	}
+	if !pathExcluded("/public/./page", "/public") {
+		t.Error("un-escaped ./ inside the excluded subtree should still be excluded")
+	}
+
+	// Dot-segment traversal must NOT escape INTO the exclusion namespace and
+	// thereby reach a sibling resource unauthenticated.
+	if pathExcluded("/public/../admin", "/public") {
+		t.Error("excluded /public must not also cover /admin reached via ../ (auth bypass)")
+	}
+	if pathExcluded("/public/..", "/public") {
+		t.Error("excluded /public must not cover root reached via ..")
+	}
+	if pathExcluded("/public/../", "/public") {
+		t.Error("excluded /public must not cover the bare root reached via ../")
+	}
+	if pathExcluded("/public/x/../../admin", "/public") {
+		t.Error("nested traversal must not escape the subtree into /admin")
+	}
+}
+
+// R89 regression: CreatePooledHTTPClient / GetOrCreateTransport must apply the
+// same zero-value defaults as CreateHTTPClient. Before, a partially populated
+// config (e.g. only {Timeout: 10s}, or zero) produced an http.Client with
+// Timeout == 0 and a transport with ResponseHeaderTimeout == 0 — an unbounded
+// stall on a hanging upstream. Both must now be bounded by the shared
+// defaults.
+func TestR89PooledClientAppliesDefaults(t *testing.T) {
+	client := CreatePooledHTTPClient(HTTPClientConfig{})
+	if client.Timeout == 0 {
+		t.Error("pooled HTTP client must carry a default overall Timeout; zero = unbounded stall")
+	}
+	tr, ok := client.Transport.(*http.Transport)
+	if !ok {
+		t.Fatalf("pooled client transport is %T, want *http.Transport", client.Transport)
+	}
+	if tr.ResponseHeaderTimeout == 0 {
+		t.Error("pooled transport must carry a default ResponseHeaderTimeout; zero = unbounded stall")
+	}
+	if tr.IdleConnTimeout == 0 {
+		t.Error("pooled transport must carry a default IdleConnTimeout")
+	}
+}

url_helpers.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net"
 	"net/url"
+	"path"
 	"strings"
 )
 
@@ -33,6 +34,16 @@ func (t *TraefikOidc) determineExcludedURL(currentRequest string) bool {
 // an unrelated sibling such as "/publicsecret", so a configured exclusion can no
 // longer be widened into an authentication bypass on a different resource.
 func pathExcluded(requestPath, excluded string) bool {
+	// Normalize dot segments and redundant slashes so an exclusion cannot be
+	// escaped by traversal. Go's server leaves ".." in req.URL.Path (verified:
+	// url.ParseRequestURI keeps dot segments), so "/public/../admin" would match
+	// an "/public" exclusion even though the real resource is "/admin". path.Clean
+	// resolves this to "/admin" before the boundary check. "." (empty or bare)
+	// maps back to "" preserving the original root-match semantics.
+	requestPath = path.Clean(requestPath)
+	if requestPath == "." {
+		requestPath = ""
+	}
 	excluded = strings.TrimRight(excluded, "/")
 	if excluded == "" {
 		// A "/" (root) exclusion only matches the root path, not everything.