Test that socket-kept netns appears in listns() output.
Verify that a network namespace kept alive by a socket FD appears in
listns() output even after the creating process exits, and that it
disappears when the socket is closed.
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
.../testing/selftests/namespaces/siocgskns_test.c | 203 +++++++++++++++++++++
1 file changed, 203 insertions(+)
diff --git a/tools/testing/selftests/namespaces/siocgskns_test.c b/tools/testing/selftests/namespaces/siocgskns_test.c
index 47c1524a8648..98f6a0e1b9dd 100644
--- a/tools/testing/selftests/namespaces/siocgskns_test.c
+++ b/tools/testing/selftests/namespaces/siocgskns_test.c
@@ -576,4 +576,207 @@ TEST(siocgskns_ipv6)
close(current_netns_fd);
}
+/*
+ * Test that socket-kept netns appears in listns() output.
+ * Verify that a network namespace kept alive by a socket FD appears in
+ * listns() output even after the creating process exits, and that it
+ * disappears when the socket is closed.
+ */
+TEST(siocgskns_listns_visibility)
+{
+ int sock_fd, netns_fd, owner_fd;
+ int ipc_sockets[2];
+ pid_t pid;
+ int status;
+ __u64 netns_id, owner_id;
+ struct ns_id_req req = {
+ .size = sizeof(req),
+ .spare = 0,
+ .ns_id = 0,
+ .ns_type = CLONE_NEWNET,
+ .spare2 = 0,
+ .user_ns_id = 0,
+ };
+ __u64 ns_ids[256];
+ int ret, i;
+ bool found_netns = false;
+
+ EXPECT_EQ(socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets), 0);
+
+ pid = fork();
+ ASSERT_GE(pid, 0);
+
+ if (pid == 0) {
+ /* Child: create new netns and socket */
+ close(ipc_sockets[0]);
+
+ if (unshare(CLONE_NEWNET) < 0) {
+ close(ipc_sockets[1]);
+ exit(1);
+ }
+
+ sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sock_fd < 0) {
+ close(ipc_sockets[1]);
+ exit(1);
+ }
+
+ /* Send socket FD to parent via SCM_RIGHTS */
+ struct msghdr msg = {0};
+ struct iovec iov = {0};
+ char buf[1] = {'X'};
+ char cmsg_buf[CMSG_SPACE(sizeof(int))];
+
+ iov.iov_base = buf;
+ iov.iov_len = 1;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ msg.msg_control = cmsg_buf;
+ msg.msg_controllen = sizeof(cmsg_buf);
+
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+ memcpy(CMSG_DATA(cmsg), &sock_fd, sizeof(int));
+
+ if (sendmsg(ipc_sockets[1], &msg, 0) < 0) {
+ close(sock_fd);
+ close(ipc_sockets[1]);
+ exit(1);
+ }
+
+ close(sock_fd);
+ close(ipc_sockets[1]);
+ exit(0);
+ }
+
+ /* Parent: receive socket FD */
+ close(ipc_sockets[1]);
+
+ struct msghdr msg = {0};
+ struct iovec iov = {0};
+ char buf[1];
+ char cmsg_buf[CMSG_SPACE(sizeof(int))];
+
+ iov.iov_base = buf;
+ iov.iov_len = 1;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ msg.msg_control = cmsg_buf;
+ msg.msg_controllen = sizeof(cmsg_buf);
+
+ ssize_t n = recvmsg(ipc_sockets[0], &msg, 0);
+ close(ipc_sockets[0]);
+ ASSERT_EQ(n, 1);
+
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+ ASSERT_NE(cmsg, NULL);
+ memcpy(&sock_fd, CMSG_DATA(cmsg), sizeof(int));
+
+ /* Wait for child to exit */
+ waitpid(pid, &status, 0);
+ ASSERT_TRUE(WIFEXITED(status));
+ ASSERT_EQ(WEXITSTATUS(status), 0);
+
+ /* Get network namespace from socket */
+ netns_fd = ioctl(sock_fd, SIOCGSKNS);
+ if (netns_fd < 0) {
+ close(sock_fd);
+ if (errno == ENOTTY || errno == EINVAL)
+ SKIP(return, "SIOCGSKNS not supported");
+ ASSERT_GE(netns_fd, 0);
+ }
+
+ /* Get namespace ID */
+ ret = ioctl(netns_fd, NS_GET_ID, &netns_id);
+ if (ret < 0) {
+ close(sock_fd);
+ close(netns_fd);
+ if (errno == ENOTTY || errno == EINVAL)
+ SKIP(return, "NS_GET_ID not supported");
+ ASSERT_EQ(ret, 0);
+ }
+
+ /* Get owner user namespace */
+ owner_fd = ioctl(netns_fd, NS_GET_USERNS);
+ if (owner_fd < 0) {
+ close(sock_fd);
+ close(netns_fd);
+ if (errno == ENOTTY || errno == EINVAL)
+ SKIP(return, "NS_GET_USERNS not supported");
+ ASSERT_GE(owner_fd, 0);
+ }
+
+ /* Get owner namespace ID */
+ ret = ioctl(owner_fd, NS_GET_ID, &owner_id);
+ if (ret < 0) {
+ close(owner_fd);
+ close(sock_fd);
+ close(netns_fd);
+ ASSERT_EQ(ret, 0);
+ }
+ close(owner_fd);
+
+ /* Namespace should appear in listns() output */
+ ret = sys_listns(&req, ns_ids, ARRAY_SIZE(ns_ids), 0);
+ if (ret < 0) {
+ close(sock_fd);
+ close(netns_fd);
+ if (errno == ENOSYS)
+ SKIP(return, "listns() not supported");
+ TH_LOG("listns failed: %s", strerror(errno));
+ ASSERT_GE(ret, 0);
+ }
+
+ /* Search for our network namespace in the list */
+ for (i = 0; i < ret; i++) {
+ if (ns_ids[i] == netns_id) {
+ found_netns = true;
+ break;
+ }
+ }
+
+ ASSERT_TRUE(found_netns);
+ TH_LOG("Found netns %llu in listns() output (kept alive by socket)", netns_id);
+
+ /* Now verify with owner filtering */
+ req.user_ns_id = owner_id;
+ found_netns = false;
+
+ ret = sys_listns(&req, ns_ids, ARRAY_SIZE(ns_ids), 0);
+ ASSERT_GE(ret, 0);
+
+ for (i = 0; i < ret; i++) {
+ if (ns_ids[i] == netns_id) {
+ found_netns = true;
+ break;
+ }
+ }
+
+ ASSERT_TRUE(found_netns);
+ TH_LOG("Found netns %llu owned by userns %llu", netns_id, owner_id);
+
+ /* Close socket - namespace should become inactive and disappear from listns() */
+ close(sock_fd);
+ close(netns_fd);
+
+ /* Verify it's no longer in listns() output */
+ req.user_ns_id = 0;
+ found_netns = false;
+
+ ret = sys_listns(&req, ns_ids, ARRAY_SIZE(ns_ids), 0);
+ ASSERT_GE(ret, 0);
+
+ for (i = 0; i < ret; i++) {
+ if (ns_ids[i] == netns_id) {
+ found_netns = true;
+ break;
+ }
+ }
+
+ ASSERT_FALSE(found_netns);
+ TH_LOG("Netns %llu correctly disappeared from listns() after socket closed", netns_id);
+}
+
TEST_HARNESS_MAIN
--
2.47.3