Problem: zmq_poller_*_fd functions do not check for invalid fd

Solution: add checks, added test cases

src/zmq.cpp

@@ -1269,6 +1269,10 @@ int zmq_poller_add_fd (void *poller_, int fd_, void *user_data_, short events_)
         errno = EFAULT;
         return -1;
     }
+    if (fd_ == zmq::retired_fd) {
+        errno = ENOTSOCK;
+        return -1;
+    }
 
     return ((zmq::socket_poller_t*)poller_)->add_fd (fd_, user_data_, events_);
 }
@@ -1301,6 +1305,10 @@ int zmq_poller_modify_fd (void *poller_, int fd_, short events_)
         errno = EFAULT;
         return -1;
     }
+    if (fd_ == zmq::retired_fd) {
+        errno = ENOTSOCK;
+        return -1;
+    }
 
     return ((zmq::socket_poller_t*)poller_)->modify_fd (fd_, events_);
 }
@@ -1332,6 +1340,10 @@ int zmq_poller_remove_fd (void *poller_, int fd_)
         errno = EFAULT;
         return -1;
     }
+    if (fd_ == zmq::retired_fd) {
+        errno = ENOTSOCK;
+        return -1;
+    }
 
     return ((zmq::socket_poller_t*)poller_)->remove_fd (fd_);
 }

tests/test_poller.cpp

@@ -29,6 +29,20 @@
 
 #include "testutil.hpp"
 
+// duplicated from fd.hpp
+#ifdef ZMQ_HAVE_WINDOWS
+#if defined _MSC_VER &&_MSC_VER <= 1400
+    typedef UINT_PTR fd_t;
+    enum {retired_fd = (fd_t)(~0)};
+#else
+    typedef SOCKET fd_t;
+    enum {retired_fd = (fd_t)INVALID_SOCKET};
+#endif
+#else
+    typedef int fd_t;
+    enum {retired_fd = -1};
+#endif
+
 void test_null_poller_pointers (void *ctx)
 {
     int rc = zmq_poller_destroy (NULL);
@@ -55,11 +69,7 @@ void test_null_poller_pointers (void *ctx)
     rc = zmq_poller_remove (&null_poller, socket);
     assert (rc == -1 && errno == EFAULT);
 
-#ifdef _WIN32
-    SOCKET fd;
-#else
-    int fd;
-#endif
+    fd_t fd;
     size_t fd_size = sizeof fd;
     rc = zmq_getsockopt(socket, ZMQ_FD, &fd, &fd_size);
     assert (rc == 0);
@@ -97,6 +107,17 @@ void test_null_socket_pointers ()
     rc = zmq_poller_remove (poller, NULL);
     assert (rc == -1 && errno == ENOTSOCK);
 
+    fd_t null_socket_fd = retired_fd;
+    
+    rc = zmq_poller_add_fd (poller, null_socket_fd, NULL, ZMQ_POLLIN);
+    assert (rc == -1 && errno == ENOTSOCK);
+
+    rc = zmq_poller_modify_fd (poller, null_socket_fd, ZMQ_POLLIN);
+    assert (rc == -1 && errno == ENOTSOCK);
+
+    rc = zmq_poller_remove_fd (poller, null_socket_fd);
+    assert (rc == -1 && errno == ENOTSOCK);
+
     rc = zmq_poller_destroy (&poller);
     assert (rc == 0);
 }