1 files changed, 184 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
new file mode 100644
index 000000000000..9c77cd6b1eaf
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2020 Google LLC.
+ */
+
+#include <asm-generic/errno-base.h>
+#include <sys/stat.h>
+#include <test_progs.h>
+#include <linux/limits.h>
+
+#include "local_storage.skel.h"
+#include "network_helpers.h"
+#include "task_local_storage_helpers.h"
+
+static unsigned int duration;
+
+#define TEST_STORAGE_VALUE 0xbeefdead
+
+struct storage {
+	void *inode;
+	unsigned int value;
+};
+
+/* Fork and exec the provided rm binary and return the exit code of the
+ * forked process and its pid.
+ */
+static int run_self_unlink(int *monitored_pid, const char *rm_path)
+{
+	int child_pid, child_status, ret;
+	int null_fd;
+
+	child_pid = fork();
+	if (child_pid == 0) {
+		null_fd = open("/dev/null", O_WRONLY);
+		dup2(null_fd, STDOUT_FILENO);
+		dup2(null_fd, STDERR_FILENO);
+		close(null_fd);
+
+		*monitored_pid = getpid();
+		/* Use the copied /usr/bin/rm to delete itself
+		 * /tmp/copy_of_rm /tmp/copy_of_rm.
+		 */
+		ret = execlp(rm_path, rm_path, rm_path, NULL);
+		if (ret)
+			exit(errno);
+	} else if (child_pid > 0) {
+		waitpid(child_pid, &child_status, 0);
+		return WEXITSTATUS(child_status);
+	}
+
+	return -EINVAL;
+}
+
+static bool check_syscall_operations(int map_fd, int obj_fd)
+{
+	struct storage val = { .value = TEST_STORAGE_VALUE },
+		       lookup_val = { .value = 0 };
+	int err;
+
+	/* Looking up an existing element should fail initially */
+	err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
+	if (CHECK(!err || errno != ENOENT, "bpf_map_lookup_elem",
+		  "err:%d errno:%d\n", err, errno))
+		return false;
+
+	/* Create a new element */
+	err = bpf_map_update_elem(map_fd, &obj_fd, &val, BPF_NOEXIST);
+	if (CHECK(err < 0, "bpf_map_update_elem", "err:%d errno:%d\n", err,
+		  errno))
+		return false;
+
+	/* Lookup the newly created element */
+	err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
+	if (CHECK(err < 0, "bpf_map_lookup_elem", "err:%d errno:%d", err,
+		  errno))
+		return false;
+
+	/* Check the value of the newly created element */
+	if (CHECK(lookup_val.value != val.value, "bpf_map_lookup_elem",
+		  "value got = %x errno:%d", lookup_val.value, val.value))
+		return false;
+
+	err = bpf_map_delete_elem(map_fd, &obj_fd);
+	if (CHECK(err, "bpf_map_delete_elem()", "err:%d errno:%d\n", err,
+		  errno))
+		return false;
+
+	/* The lookup should fail, now that the element has been deleted */
+	err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
+	if (CHECK(!err || errno != ENOENT, "bpf_map_lookup_elem",
+		  "err:%d errno:%d\n", err, errno))
+		return false;
+
+	return true;
+}
+
+void test_test_local_storage(void)
+{
+	char tmp_dir_path[] = "/tmp/local_storageXXXXXX";
+	int err, serv_sk = -1, task_fd = -1, rm_fd = -1;
+	struct local_storage *skel = NULL;
+	char tmp_exec_path[64];
+	char cmd[256];
+
+	skel = local_storage__open_and_load();
+	if (CHECK(!skel, "skel_load", "lsm skeleton failed\n"))
+		goto close_prog;
+
+	err = local_storage__attach(skel);
+	if (CHECK(err, "attach", "lsm attach failed: %d\n", err))
+		goto close_prog;
+
+	task_fd = sys_pidfd_open(getpid(), 0);
+	if (CHECK(task_fd < 0, "pidfd_open",
+		  "failed to get pidfd err:%d, errno:%d", task_fd, errno))
+		goto close_prog;
+
+	if (!check_syscall_operations(bpf_map__fd(skel->maps.task_storage_map),
+				      task_fd))
+		goto close_prog;
+
+	if (CHECK(!mkdtemp(tmp_dir_path), "mkdtemp",
+		  "unable to create tmpdir: %d\n", errno))
+		goto close_prog;
+
+	snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm",
+		 tmp_dir_path);
+	snprintf(cmd, sizeof(cmd), "cp /bin/rm %s", tmp_exec_path);
+	if (CHECK_FAIL(system(cmd)))
+		goto close_prog_rmdir;
+
+	rm_fd = open(tmp_exec_path, O_RDONLY);
+	if (CHECK(rm_fd < 0, "open", "failed to open %s err:%d, errno:%d",
+		  tmp_exec_path, rm_fd, errno))
+		goto close_prog_rmdir;
+
+	if (!check_syscall_operations(bpf_map__fd(skel->maps.inode_storage_map),
+				      rm_fd))
+		goto close_prog_rmdir;
+
+	/* Sets skel->bss->monitored_pid to the pid of the forked child
+	 * forks a child process that executes tmp_exec_path and tries to
+	 * unlink its executable. This operation should be denied by the loaded
+	 * LSM program.
+	 */
+	err = run_self_unlink(&skel->bss->monitored_pid, tmp_exec_path);
+	if (CHECK(err != EPERM, "run_self_unlink", "err %d want EPERM\n", err))
+		goto close_prog_rmdir;
+
+	/* Set the process being monitored to be the current process */
+	skel->bss->monitored_pid = getpid();
+
+	/* Move copy_of_rm to a new location so that it triggers the
+	 * inode_rename LSM hook with a new_dentry that has a NULL inode ptr.
+	 */
+	snprintf(cmd, sizeof(cmd), "mv %s/copy_of_rm %s/check_null_ptr",
+		 tmp_dir_path, tmp_dir_path);
+	if (CHECK_FAIL(system(cmd)))
+		goto close_prog_rmdir;
+
+	CHECK(skel->data->inode_storage_result != 0, "inode_storage_result",
+	      "inode_local_storage not set\n");
+
+	serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
+	if (CHECK(serv_sk < 0, "start_server", "failed to start server\n"))
+		goto close_prog_rmdir;
+
+	CHECK(skel->data->sk_storage_result != 0, "sk_storage_result",
+	      "sk_local_storage not set\n");
+
+	if (!check_syscall_operations(bpf_map__fd(skel->maps.sk_storage_map),
+				      serv_sk))
+		goto close_prog_rmdir;
+
+close_prog_rmdir:
+	snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir_path);
+	system(cmd);
+close_prog:
+	close(serv_sk);
+	close(rm_fd);
+	close(task_fd);
+	local_storage__destroy(skel);
+}