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 --- .../testing/selftests/namespaces/siocgskns_test.c | 204 +++++++++++++++++++++ 1 file changed, 204 insertions(+) diff --git a/tools/testing/selftests/namespaces/siocgskns_test.c b/tools/testing/selftests/namespaces/siocgskns_test.c index 1c40c7772ad4..7b3133f3898c 100644 --- a/tools/testing/selftests/namespaces/siocgskns_test.c +++ b/tools/testing/selftests/namespaces/siocgskns_test.c @@ -577,4 +577,208 @@ 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)); + if (WEXITSTATUS(status) != 0) + SKIP(close(sock_fd); return, "Child failed to create namespace"); + + /* 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