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-rw-r--r--tools/testing/selftests/namespaces/siocgskns_test.c564
1 files changed, 564 insertions, 0 deletions
diff --git a/tools/testing/selftests/namespaces/siocgskns_test.c b/tools/testing/selftests/namespaces/siocgskns_test.c
index 706049768d52..ba689a22d82f 100644
--- a/tools/testing/selftests/namespaces/siocgskns_test.c
+++ b/tools/testing/selftests/namespaces/siocgskns_test.c
@@ -1257,4 +1257,568 @@ TEST(siocgskns_listns_and_file_handle)
free(handle);
}
+/*
+ * Test multi-level namespace resurrection across three user namespace levels.
+ *
+ * This test creates a complex namespace hierarchy with three levels of user
+ * namespaces and a network namespace at the deepest level. It verifies that
+ * the resurrection semantics work correctly when SIOCGSKNS is called on a
+ * socket from an inactive namespace tree, and that listns() and
+ * open_by_handle_at() correctly respect visibility rules.
+ *
+ * Hierarchy after child processes exit (all with 0 active refcount):
+ *
+ * net_L3A (0) <- Level 3 network namespace
+ * |
+ * +
+ * userns_L3 (0) <- Level 3 user namespace
+ * |
+ * +
+ * userns_L2 (0) <- Level 2 user namespace
+ * |
+ * +
+ * userns_L1 (0) <- Level 1 user namespace
+ * |
+ * x
+ * init_user_ns
+ *
+ * The test verifies:
+ * 1. SIOCGSKNS on a socket from inactive net_L3A resurrects the entire chain
+ * 2. After resurrection, all namespaces are visible in listns()
+ * 3. Resurrected namespaces can be reopened via file handles
+ * 4. Closing the netns FD cascades down: the entire ownership chain
+ * (userns_L3 -> userns_L2 -> userns_L1) becomes inactive again
+ * 5. Inactive namespaces disappear from listns() and cannot be reopened
+ * 6. Calling SIOCGSKNS again on the same socket resurrects the tree again
+ * 7. After second resurrection, namespaces are visible and can be reopened
+ */
+TEST(siocgskns_multilevel_resurrection)
+{
+ int ipc_sockets[2];
+ pid_t pid_l1, pid_l2, pid_l3;
+ int status;
+
+ /* Namespace file descriptors to be received from child */
+ int sock_L3A_fd = -1;
+ int netns_L3A_fd = -1;
+ __u64 netns_L3A_id;
+ __u64 userns_L1_id, userns_L2_id, userns_L3_id;
+
+ /* For listns() and file handle testing */
+ struct ns_id_req req = {
+ .size = sizeof(req),
+ .spare = 0,
+ .ns_id = 0,
+ .ns_type = CLONE_NEWNET | CLONE_NEWUSER,
+ .spare2 = 0,
+ .user_ns_id = 0,
+ };
+ __u64 ns_ids[256];
+ int ret, i;
+ struct file_handle *handle;
+ struct nsfs_file_handle *nsfs_fh;
+ int reopened_fd;
+
+ /* Allocate file handle for testing */
+ handle = malloc(sizeof(struct file_handle) + sizeof(struct nsfs_file_handle));
+ ASSERT_NE(handle, NULL);
+ handle->handle_bytes = sizeof(struct nsfs_file_handle);
+ handle->handle_type = FILEID_NSFS;
+
+ EXPECT_EQ(socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets), 0);
+
+ /*
+ * Fork level 1 child that creates userns_L1
+ */
+ pid_l1 = fork();
+ ASSERT_GE(pid_l1, 0);
+
+ if (pid_l1 == 0) {
+ /* Level 1 child */
+ int ipc_L2[2];
+ close(ipc_sockets[0]);
+
+ /* Create userns_L1 */
+ if (setup_userns() < 0) {
+ close(ipc_sockets[1]);
+ exit(1);
+ }
+
+ /* Create socketpair for communicating with L2 child */
+ if (socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_L2) < 0) {
+ close(ipc_sockets[1]);
+ exit(1);
+ }
+
+ /*
+ * Fork level 2 child that creates userns_L2
+ */
+ pid_l2 = fork();
+ if (pid_l2 < 0) {
+ close(ipc_sockets[1]);
+ close(ipc_L2[0]);
+ close(ipc_L2[1]);
+ exit(1);
+ }
+
+ if (pid_l2 == 0) {
+ /* Level 2 child */
+ int ipc_L3[2];
+ close(ipc_L2[0]);
+
+ /* Create userns_L2 (nested inside userns_L1) */
+ if (setup_userns() < 0) {
+ close(ipc_L2[1]);
+ exit(1);
+ }
+
+ /* Create socketpair for communicating with L3 child */
+ if (socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_L3) < 0) {
+ close(ipc_L2[1]);
+ exit(1);
+ }
+
+ /*
+ * Fork level 3 child that creates userns_L3 and network namespaces
+ */
+ pid_l3 = fork();
+ if (pid_l3 < 0) {
+ close(ipc_L2[1]);
+ close(ipc_L3[0]);
+ close(ipc_L3[1]);
+ exit(1);
+ }
+
+ if (pid_l3 == 0) {
+ /* Level 3 child - the deepest level */
+ int sock_fd;
+ close(ipc_L3[0]);
+
+ /* Create userns_L3 (nested inside userns_L2) */
+ if (setup_userns() < 0) {
+ close(ipc_L3[1]);
+ exit(1);
+ }
+
+ /* Create network namespace at level 3 */
+ if (unshare(CLONE_NEWNET) < 0) {
+ close(ipc_L3[1]);
+ exit(1);
+ }
+
+ /* Create socket in net_L3A */
+ sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sock_fd < 0) {
+ close(ipc_L3[1]);
+ exit(1);
+ }
+
+ /* Send socket FD to L2 parent */
+ 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_L3[1], &msg, 0) < 0) {
+ close(sock_fd);
+ close(ipc_L3[1]);
+ exit(1);
+ }
+
+ close(sock_fd);
+ close(ipc_L3[1]);
+ exit(0);
+ }
+
+ /* Level 2 child - receive from L3 and forward to L1 */
+ close(ipc_L3[1]);
+
+ struct msghdr msg = {0};
+ struct iovec iov = {0};
+ char buf[1];
+ char cmsg_buf[CMSG_SPACE(sizeof(int))];
+ int received_fd;
+
+ 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_L3[0], &msg, 0);
+ close(ipc_L3[0]);
+
+ if (n != 1) {
+ close(ipc_L2[1]);
+ waitpid(pid_l3, NULL, 0);
+ exit(1);
+ }
+
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+ if (!cmsg) {
+ close(ipc_L2[1]);
+ waitpid(pid_l3, NULL, 0);
+ exit(1);
+ }
+ memcpy(&received_fd, CMSG_DATA(cmsg), sizeof(int));
+
+ /* Wait for L3 child */
+ waitpid(pid_l3, NULL, 0);
+
+ /* Forward the socket FD to L1 parent */
+ memset(&msg, 0, sizeof(msg));
+ buf[0] = 'Y';
+ 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);
+
+ 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), &received_fd, sizeof(int));
+
+ if (sendmsg(ipc_L2[1], &msg, 0) < 0) {
+ close(received_fd);
+ close(ipc_L2[1]);
+ exit(1);
+ }
+
+ close(received_fd);
+ close(ipc_L2[1]);
+ exit(0);
+ }
+
+ /* Level 1 child - receive from L2 and forward to parent */
+ close(ipc_L2[1]);
+
+ struct msghdr msg = {0};
+ struct iovec iov = {0};
+ char buf[1];
+ char cmsg_buf[CMSG_SPACE(sizeof(int))];
+ int received_fd;
+
+ 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_L2[0], &msg, 0);
+ close(ipc_L2[0]);
+
+ if (n != 1) {
+ close(ipc_sockets[1]);
+ waitpid(pid_l2, NULL, 0);
+ exit(1);
+ }
+
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+ if (!cmsg) {
+ close(ipc_sockets[1]);
+ waitpid(pid_l2, NULL, 0);
+ exit(1);
+ }
+ memcpy(&received_fd, CMSG_DATA(cmsg), sizeof(int));
+
+ /* Wait for L2 child */
+ waitpid(pid_l2, NULL, 0);
+
+ /* Forward the socket FD to parent */
+ memset(&msg, 0, sizeof(msg));
+ buf[0] = 'Z';
+ 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);
+
+ 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), &received_fd, sizeof(int));
+
+ if (sendmsg(ipc_sockets[1], &msg, 0) < 0) {
+ close(received_fd);
+ close(ipc_sockets[1]);
+ exit(1);
+ }
+
+ close(received_fd);
+ close(ipc_sockets[1]);
+ exit(0);
+ }
+
+ /* Parent - receive the socket from the deepest level */
+ 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]);
+
+ if (n != 1) {
+ free(handle);
+ waitpid(pid_l1, NULL, 0);
+ SKIP(return, "Failed to receive socket from child");
+ }
+
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+ if (!cmsg) {
+ free(handle);
+ waitpid(pid_l1, NULL, 0);
+ SKIP(return, "Failed to receive socket from child");
+ }
+ memcpy(&sock_L3A_fd, CMSG_DATA(cmsg), sizeof(int));
+
+ /* Wait for L1 child */
+ waitpid(pid_l1, &status, 0);
+ ASSERT_TRUE(WIFEXITED(status));
+ ASSERT_EQ(WEXITSTATUS(status), 0);
+
+ /*
+ * At this point, all child processes have exited. The socket itself
+ * doesn't keep the namespace active - we need to call SIOCGSKNS which
+ * will resurrect the entire namespace tree by taking active references.
+ */
+
+ /* Get network namespace from socket - this resurrects the tree */
+ netns_L3A_fd = ioctl(sock_L3A_fd, SIOCGSKNS);
+ if (netns_L3A_fd < 0) {
+ free(handle);
+ close(sock_L3A_fd);
+ if (errno == ENOTTY || errno == EINVAL)
+ SKIP(return, "SIOCGSKNS not supported");
+ ASSERT_GE(netns_L3A_fd, 0);
+ }
+
+ /* Get namespace ID for net_L3A */
+ ret = ioctl(netns_L3A_fd, NS_GET_ID, &netns_L3A_id);
+ if (ret < 0) {
+ free(handle);
+ close(sock_L3A_fd);
+ close(netns_L3A_fd);
+ if (errno == ENOTTY || errno == EINVAL)
+ SKIP(return, "NS_GET_ID not supported");
+ ASSERT_EQ(ret, 0);
+ }
+
+ /* Get owner user namespace chain: userns_L3 -> userns_L2 -> userns_L1 */
+ int userns_L3_fd = ioctl(netns_L3A_fd, NS_GET_USERNS);
+ if (userns_L3_fd < 0) {
+ free(handle);
+ close(sock_L3A_fd);
+ close(netns_L3A_fd);
+ if (errno == ENOTTY || errno == EINVAL)
+ SKIP(return, "NS_GET_USERNS not supported");
+ ASSERT_GE(userns_L3_fd, 0);
+ }
+
+ ret = ioctl(userns_L3_fd, NS_GET_ID, &userns_L3_id);
+ ASSERT_EQ(ret, 0);
+
+ int userns_L2_fd = ioctl(userns_L3_fd, NS_GET_USERNS);
+ ASSERT_GE(userns_L2_fd, 0);
+ ret = ioctl(userns_L2_fd, NS_GET_ID, &userns_L2_id);
+ ASSERT_EQ(ret, 0);
+
+ int userns_L1_fd = ioctl(userns_L2_fd, NS_GET_USERNS);
+ ASSERT_GE(userns_L1_fd, 0);
+ ret = ioctl(userns_L1_fd, NS_GET_ID, &userns_L1_id);
+ ASSERT_EQ(ret, 0);
+
+ close(userns_L1_fd);
+ close(userns_L2_fd);
+ close(userns_L3_fd);
+
+ TH_LOG("Multi-level hierarchy: net_L3A (id=%llu) -> userns_L3 (id=%llu) -> userns_L2 (id=%llu) -> userns_L1 (id=%llu)",
+ netns_L3A_id, userns_L3_id, userns_L2_id, userns_L1_id);
+
+ /*
+ * Test 1: Verify net_L3A is visible in listns() after resurrection.
+ * The entire ownership chain should be resurrected and visible.
+ */
+ ret = sys_listns(&req, ns_ids, ARRAY_SIZE(ns_ids), 0);
+ if (ret < 0) {
+ free(handle);
+ close(sock_L3A_fd);
+ close(netns_L3A_fd);
+ if (errno == ENOSYS)
+ SKIP(return, "listns() not supported");
+ ASSERT_GE(ret, 0);
+ }
+
+ bool found_netns_L3A = false;
+ bool found_userns_L1 = false;
+ bool found_userns_L2 = false;
+ bool found_userns_L3 = false;
+
+ for (i = 0; i < ret; i++) {
+ if (ns_ids[i] == netns_L3A_id)
+ found_netns_L3A = true;
+ if (ns_ids[i] == userns_L1_id)
+ found_userns_L1 = true;
+ if (ns_ids[i] == userns_L2_id)
+ found_userns_L2 = true;
+ if (ns_ids[i] == userns_L3_id)
+ found_userns_L3 = true;
+ }
+
+ ASSERT_TRUE(found_netns_L3A);
+ ASSERT_TRUE(found_userns_L1);
+ ASSERT_TRUE(found_userns_L2);
+ ASSERT_TRUE(found_userns_L3);
+ TH_LOG("Resurrection verified: all namespaces in hierarchy visible in listns()");
+
+ /*
+ * Test 2: Verify net_L3A can be reopened via file handle.
+ */
+ nsfs_fh = (struct nsfs_file_handle *)handle->f_handle;
+ nsfs_fh->ns_id = netns_L3A_id;
+ nsfs_fh->ns_type = 0;
+ nsfs_fh->ns_inum = 0;
+
+ reopened_fd = open_by_handle_at(FD_NSFS_ROOT, handle, O_RDONLY);
+ if (reopened_fd < 0) {
+ free(handle);
+ close(sock_L3A_fd);
+ close(netns_L3A_fd);
+ if (errno == EOPNOTSUPP || errno == ENOSYS || errno == EBADF)
+ SKIP(return, "open_by_handle_at with FD_NSFS_ROOT not supported");
+ TH_LOG("open_by_handle_at failed: %s", strerror(errno));
+ ASSERT_GE(reopened_fd, 0);
+ }
+
+ close(reopened_fd);
+ TH_LOG("File handle test passed: net_L3A can be reopened");
+
+ /*
+ * Test 3: Verify that when we close the netns FD (dropping the last
+ * active reference), the entire tree becomes inactive and disappears
+ * from listns(). The cascade goes: net_L3A drops -> userns_L3 drops ->
+ * userns_L2 drops -> userns_L1 drops.
+ */
+ close(netns_L3A_fd);
+
+ ret = sys_listns(&req, ns_ids, ARRAY_SIZE(ns_ids), 0);
+ ASSERT_GE(ret, 0);
+
+ found_netns_L3A = false;
+ found_userns_L1 = false;
+ found_userns_L2 = false;
+ found_userns_L3 = false;
+
+ for (i = 0; i < ret; i++) {
+ if (ns_ids[i] == netns_L3A_id)
+ found_netns_L3A = true;
+ if (ns_ids[i] == userns_L1_id)
+ found_userns_L1 = true;
+ if (ns_ids[i] == userns_L2_id)
+ found_userns_L2 = true;
+ if (ns_ids[i] == userns_L3_id)
+ found_userns_L3 = true;
+ }
+
+ ASSERT_FALSE(found_netns_L3A);
+ ASSERT_FALSE(found_userns_L1);
+ ASSERT_FALSE(found_userns_L2);
+ ASSERT_FALSE(found_userns_L3);
+ TH_LOG("Cascade test passed: all namespaces disappeared after netns FD closed");
+
+ /*
+ * Test 4: Verify file handle no longer works for inactive namespace.
+ */
+ reopened_fd = open_by_handle_at(FD_NSFS_ROOT, handle, O_RDONLY);
+ if (reopened_fd >= 0) {
+ close(reopened_fd);
+ free(handle);
+ ASSERT_TRUE(false); /* Should have failed */
+ }
+ TH_LOG("Inactive namespace correctly cannot be reopened via file handle");
+
+ /*
+ * Test 5: Verify that calling SIOCGSKNS again resurrects the tree again.
+ * The socket is still valid, so we can call SIOCGSKNS on it to resurrect
+ * the namespace tree once more.
+ */
+ netns_L3A_fd = ioctl(sock_L3A_fd, SIOCGSKNS);
+ ASSERT_GE(netns_L3A_fd, 0);
+
+ TH_LOG("Called SIOCGSKNS again to resurrect the namespace tree");
+
+ /* Verify the namespace tree is resurrected and visible in listns() */
+ ret = sys_listns(&req, ns_ids, ARRAY_SIZE(ns_ids), 0);
+ ASSERT_GE(ret, 0);
+
+ found_netns_L3A = false;
+ found_userns_L1 = false;
+ found_userns_L2 = false;
+ found_userns_L3 = false;
+
+ for (i = 0; i < ret; i++) {
+ if (ns_ids[i] == netns_L3A_id)
+ found_netns_L3A = true;
+ if (ns_ids[i] == userns_L1_id)
+ found_userns_L1 = true;
+ if (ns_ids[i] == userns_L2_id)
+ found_userns_L2 = true;
+ if (ns_ids[i] == userns_L3_id)
+ found_userns_L3 = true;
+ }
+
+ ASSERT_TRUE(found_netns_L3A);
+ ASSERT_TRUE(found_userns_L1);
+ ASSERT_TRUE(found_userns_L2);
+ ASSERT_TRUE(found_userns_L3);
+ TH_LOG("Second resurrection verified: all namespaces in hierarchy visible in listns() again");
+
+ /* Verify we can reopen via file handle again */
+ reopened_fd = open_by_handle_at(FD_NSFS_ROOT, handle, O_RDONLY);
+ if (reopened_fd < 0) {
+ free(handle);
+ close(sock_L3A_fd);
+ close(netns_L3A_fd);
+ TH_LOG("open_by_handle_at failed after second resurrection: %s", strerror(errno));
+ ASSERT_GE(reopened_fd, 0);
+ }
+
+ close(reopened_fd);
+ TH_LOG("File handle test passed: net_L3A can be reopened after second resurrection");
+
+ /* Final cleanup */
+ close(sock_L3A_fd);
+ close(netns_L3A_fd);
+ free(handle);
+}
+
TEST_HARNESS_MAIN
generated by cgit (git 2.34.1) at 2025-12-25 22:08:48 +0000