1 files changed, 135 insertions, 23 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
index 91cd6f357246..bcf2e1905ed7 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
@@ -4,57 +4,169 @@
  * 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"
 
-int create_and_unlink_file(void)
-{
-	char fname[PATH_MAX] = "/tmp/fileXXXXXX";
-	int fd;
+#define TEST_STORAGE_VALUE 0xbeefdead
+
+struct storage {
+	void *inode;
+	unsigned int value;
+};
 
-	fd = mkstemp(fname);
-	if (fd < 0)
-		return fd;
+/* Fork and exec the provided rm binary and return the exit code of the
+ * forked process and its pid.
+ */
+static int run_self_unlink(struct local_storage *skel, 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);
+
+		skel->bss->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);
+		ASSERT_EQ(skel->data->task_storage_result, 0, "task_storage_result");
+		return WEXITSTATUS(child_status);
+	}
+
+	return -EINVAL;
+}
 
-	close(fd);
-	unlink(fname);
-	return 0;
+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 (!ASSERT_EQ(err, -ENOENT, "bpf_map_lookup_elem"))
+		return false;
+
+	/* Create a new element */
+	err = bpf_map_update_elem(map_fd, &obj_fd, &val, BPF_NOEXIST);
+	if (!ASSERT_OK(err, "bpf_map_update_elem"))
+		return false;
+
+	/* Lookup the newly created element */
+	err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
+	if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
+		return false;
+
+	/* Check the value of the newly created element */
+	if (!ASSERT_EQ(lookup_val.value, val.value, "bpf_map_lookup_elem"))
+		return false;
+
+	err = bpf_map_delete_elem(map_fd, &obj_fd);
+	if (!ASSERT_OK(err, "bpf_map_delete_elem()"))
+		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 (!ASSERT_EQ(err, -ENOENT, "bpf_map_lookup_elem"))
+		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;
-	int err, duration = 0, serv_sk = -1;
+	char tmp_exec_path[64];
+	char cmd[256];
 
 	skel = local_storage__open_and_load();
-	if (CHECK(!skel, "skel_load", "lsm skeleton failed\n"))
+	if (!ASSERT_OK_PTR(skel, "skel_load"))
 		goto close_prog;
 
 	err = local_storage__attach(skel);
-	if (CHECK(err, "attach", "lsm attach failed: %d\n", err))
+	if (!ASSERT_OK(err, "attach"))
 		goto close_prog;
 
-	skel->bss->monitored_pid = getpid();
+	task_fd = sys_pidfd_open(getpid(), 0);
+	if (!ASSERT_GE(task_fd, 0, "pidfd_open"))
+		goto close_prog;
 
-	err = create_and_unlink_file();
-	if (CHECK(err < 0, "exec_cmd", "err %d errno %d\n", err, errno))
+	if (!check_syscall_operations(bpf_map__fd(skel->maps.task_storage_map),
+				      task_fd))
 		goto close_prog;
 
-	CHECK(skel->data->inode_storage_result != 0, "inode_storage_result",
-	      "inode_local_storage not set\n");
+	if (!ASSERT_OK_PTR(mkdtemp(tmp_dir_path), "mkdtemp"))
+		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 (!ASSERT_OK(system(cmd), "system(cp)"))
+		goto close_prog_rmdir;
+
+	rm_fd = open(tmp_exec_path, O_RDONLY);
+	if (!ASSERT_GE(rm_fd, 0, "open(tmp_exec_path)"))
+		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, tmp_exec_path);
+	if (!ASSERT_EQ(err, EPERM, "run_self_unlink"))
+		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 (!ASSERT_OK(system(cmd), "system(mv)"))
+		goto close_prog_rmdir;
+
+	ASSERT_EQ(skel->data->inode_storage_result, 0, "inode_storage_result");
 
 	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;
+	if (!ASSERT_GE(serv_sk, 0, "start_server"))
+		goto close_prog_rmdir;
 
-	CHECK(skel->data->sk_storage_result != 0, "sk_storage_result",
-	      "sk_local_storage not set\n");
+	ASSERT_EQ(skel->data->sk_storage_result, 0, "sk_storage_result");
 
-	close(serv_sk);
+	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);
 }