pentest: bind unlock cookie to HMAC per-paste token; serve only safe content types on /raw and can items with nosniff (#34)

pentest_cookie_test.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+// #34: the unlock cookie must be bound to the paste it unlocks, not a
+// forgeable static value. A forged 'pw_<id>=1' cookie must not bypass the
+// password check on the paste page.
+func TestForgedUnlockCookieDoesNotBypassPassword(t *testing.T) {
+	globalLimiter = newLimiter()
+	s := testServer(t)
+	h := s.routes()
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest("POST", "/api/pastes", strings.NewReader(`{"content":"SECRETPASTECONTENT","password":"hunter2"}`))
+	h.ServeHTTP(rec, req)
+	if rec.Code != 201 {
+		t.Fatalf("create: got %d", rec.Code)
+	}
+	var created struct {
+		ID string `json:"id"`
+	}
+	json.Unmarshal(rec.Body.Bytes(), &created)
+	id := created.ID
+
+	// request the page with a forged unlock cookie in the old format
+	rec = httptest.NewRecorder()
+	req = httptest.NewRequest("GET", "/"+id, nil)
+	req.AddCookie(&http.Cookie{Name: "pw_" + id, Value: "1"})
+	h.ServeHTTP(rec, req)
+	if rec.Code == 200 && strings.Contains(rec.Body.String(), "SECRETPASTECONTENT") {
+		t.Fatal("forged pw_<id>=1 cookie bypassed password protection")
+	}
+	if rec.Code != 200 {
+		t.Logf("forged-cookie request returned %d (page still locked) — good", rec.Code)
+	}
+}