[FIXED JENKINS-23294] Interpret X-Forwarded-Port

- Also fixed handling of X-Forwarded-Proto and added support for X-Forwarded-Host - Additional complexity is that there can be multiple headers with the same name (which was handled by default by accident) and that a header value may contain a comma separated list if there were multiple forwarding hops.
jenkinsci · Jun 19, 2014 · 333b05e · 333b05e
2 parents cffe9df + 5bad446
commit 333b05e
Showing 1 changed file with 30 additions and 8 deletions.
diff --git a/core/src/main/java/jenkins/model/Jenkins.java b/core/src/main/java/jenkins/model/Jenkins.java
@@ -1891,22 +1891,44 @@ public boolean isRootUrlSecure() {
             throw new IllegalStateException("cannot call getRootUrlFromRequest from outside a request handling thread");
         }
         StringBuilder buf = new StringBuilder();
-        String scheme = req.getScheme();
-        String forwardedScheme = req.getHeader("X-Forwarded-Proto");
-        if (forwardedScheme != null) {
-            scheme = forwardedScheme;
+        String scheme = getXForwardedHeader(req, "X-Forwarded-Proto", req.getScheme());
+        buf.append(scheme).append("://");
+        String host = getXForwardedHeader(req, "X-Forwarded-Host", req.getServerName());
+        buf.append(host);
+        int port = req.getServerPort();
+        String forwardedPort = getXForwardedHeader(req, "X-Forwarded-Port", null);
+        if (forwardedPort != null) {
+            try {
+                port = Integer.parseInt(forwardedPort);
+            } catch (NumberFormatException e) {
+                // ignore
+            }
         }
-        buf.append(scheme+"://");
-        buf.append(req.getServerName());
-        int forwardedPort = req.getIntHeader("X-Forwarded-Port");
-        int port = forwardedPort == -1 ? req.getServerPort() : forwardedPort;
         if (port != ("https".equals(scheme) ? 443 : 80)) {
             buf.append(':').append(port);
         }
         buf.append(req.getContextPath()).append('/');
         return buf.toString();
     }
 
+    /**
+     * Gets the originating "X-Forwarded-..." header from the request. If there are multiple headers the originating
+     * header is the first header. If the originating header contains a comma separated list, the originating entry
+     * is the first one.
+     * @param req the request
+     * @param header the header name
+     * @param defaultValue the value to return if the header is absent.
+     * @return the originating entry of the header or the default value if the header was not present.
+     */
+    private static String getXForwardedHeader(StaplerRequest req, String header, String defaultValue) {
+        String value = req.getHeader(header);
+        if (value != null) {
+            int index = value.indexOf(',');
+            return index == -1 ? value.trim() : value.substring(0,index).trim();
+        }
+        return defaultValue;
+    }
+
     public File getRootDir() {
         return root;
     }