CVE-2025-31720

@@ -291,6 +291,8 @@ public synchronized void doCreateItem(StaplerRequest2 req, StaplerResponse2 rsp,
                 }
             }
 
+            src.checkPermission(Computer.EXTENDED_READ);
+
             // copy through XStream
             String xml = Jenkins.XSTREAM.toXML(src);
             Node result = (Node) Jenkins.XSTREAM.fromXML(xml);

@@ -0,0 +1,62 @@
+package jenkins.security;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.junit.Assert.assertEquals;
+
+import hudson.model.Computer;
+import hudson.slaves.DumbSlave;
+import java.net.URL;
+import jenkins.model.Jenkins;
+import org.htmlunit.HttpMethod;
+import org.htmlunit.WebRequest;
+import org.htmlunit.WebResponse;
+import org.junit.Rule;
+import org.junit.Test;
+import org.jvnet.hudson.test.Issue;
+import org.jvnet.hudson.test.JenkinsRule;
+import org.jvnet.hudson.test.MockAuthorizationStrategy;
+
+public class Security3512Test {
+
+    @Rule
+    public JenkinsRule j = new JenkinsRule();
+
+    @Test
+    @Issue("SECURITY-3512")
+    public void copyAgentTest() throws Exception {
+        Computer.EXTENDED_READ.setEnabled(true);
+        j.jenkins.setSecurityRealm(j.createDummySecurityRealm());
+        MockAuthorizationStrategy mockAuthorizationStrategy = new MockAuthorizationStrategy();
+        mockAuthorizationStrategy.grant(Jenkins.READ, Computer.CREATE, Computer.EXTENDED_READ).everywhere().to("alice");
+        mockAuthorizationStrategy.grant(Jenkins.READ, Computer.CREATE).everywhere().to("bob");
+        j.jenkins.setAuthorizationStrategy(mockAuthorizationStrategy);
+
+        DumbSlave agent = j.createOnlineSlave();
+
+        assertEquals(2, j.getInstance().getComputers().length);
+
+        String agentCopyURL = j.getURL() + "/computer/createItem?mode=copy&from=" + agent.getNodeName() + "&name=";
+
+        { // with ExtendedRead permission you can copy a node
+            try (JenkinsRule.WebClient wc = j.createWebClient().withThrowExceptionOnFailingStatusCode(false).login("alice")) {
+                WebResponse rsp = wc.getPage(wc.addCrumb(new WebRequest(new URL(agentCopyURL + "aliceAgent"),
+                        HttpMethod.POST))).getWebResponse();
+
+                assertEquals(200, rsp.getStatusCode());
+                assertEquals(3, j.getInstance().getComputers().length);
+            }
+        }
+
+        { // without ExtendedRead permission you cannot copy a node
+            try (JenkinsRule.WebClient wc = j.createWebClient().withThrowExceptionOnFailingStatusCode(false).login("bob")) {
+                WebResponse rsp = wc.getPage(wc.addCrumb(new WebRequest(new URL(agentCopyURL + "bobAgent"),
+                        HttpMethod.POST))).getWebResponse();
+
+                assertEquals(403, rsp.getStatusCode());
+                assertThat(rsp.getContentAsString(), containsString("bob is missing the Agent/ExtendedRead permission"));
+                assertEquals(3, j.getInstance().getComputers().length);
+            }
+        }
+    }
+}