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authorRoman Gushchin <guro@fb.com>2017-11-05 08:15:34 -0500
committerDavid S. Miller <davem@davemloft.net>2017-11-05 23:26:51 +0900
commit37f1ba0909dfa12c75f8e8ea7a2f01355ebd60f1 (patch)
treea6b3aebc786eeb512dfde7d6bae130cc136ede4b /tools/testing/selftests/bpf/test_dev_cgroup.c
parentbpf: move cgroup_helpers from samples/bpf/ to tools/testing/selftesting/bpf/ (diff)
downloadlinux-dev-37f1ba0909dfa12c75f8e8ea7a2f01355ebd60f1.tar.xz
linux-dev-37f1ba0909dfa12c75f8e8ea7a2f01355ebd60f1.zip
selftests/bpf: add a test for device cgroup controller
Add a test for device cgroup controller. The test loads a simple bpf program which logs all device access attempts using trace_printk() and forbids all operations except operations with /dev/zero and /dev/urandom. Then the test creates and joins a test cgroup, and attaches the bpf program to it. Then it tries to perform some simple device operations and checks the result: create /dev/null (should fail) create /dev/zero (should pass) copy data from /dev/urandom to /dev/zero (should pass) copy data from /dev/urandom to /dev/full (should fail) copy data from /dev/random to /dev/zero (should fail) Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools/testing/selftests/bpf/test_dev_cgroup.c')
-rw-r--r--tools/testing/selftests/bpf/test_dev_cgroup.c93
1 files changed, 93 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_dev_cgroup.c b/tools/testing/selftests/bpf/test_dev_cgroup.c
new file mode 100644
index 000000000000..02c85d6c89b0
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_dev_cgroup.c
@@ -0,0 +1,93 @@
+/* Copyright (c) 2017 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <linux/bpf.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "cgroup_helpers.h"
+
+#define DEV_CGROUP_PROG "./dev_cgroup.o"
+
+#define TEST_CGROUP "test-bpf-based-device-cgroup/"
+
+int main(int argc, char **argv)
+{
+ struct bpf_object *obj;
+ int error = EXIT_FAILURE;
+ int prog_fd, cgroup_fd;
+ __u32 prog_cnt;
+
+ if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
+ &obj, &prog_fd)) {
+ printf("Failed to load DEV_CGROUP program\n");
+ goto err;
+ }
+
+ if (setup_cgroup_environment()) {
+ printf("Failed to load DEV_CGROUP program\n");
+ goto err;
+ }
+
+ /* Create a cgroup, get fd, and join it */
+ cgroup_fd = create_and_get_cgroup(TEST_CGROUP);
+ if (!cgroup_fd) {
+ printf("Failed to create test cgroup\n");
+ goto err;
+ }
+
+ if (join_cgroup(TEST_CGROUP)) {
+ printf("Failed to join cgroup\n");
+ goto err;
+ }
+
+ /* Attach bpf program */
+ if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
+ printf("Failed to attach DEV_CGROUP program");
+ goto err;
+ }
+
+ if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
+ &prog_cnt)) {
+ printf("Failed to query attached programs");
+ goto err;
+ }
+
+ /* All operations with /dev/zero and and /dev/urandom are allowed,
+ * everything else is forbidden.
+ */
+ assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
+ assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
+ assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
+
+ /* /dev/zero is whitelisted */
+ assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
+ assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
+ assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
+
+ assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
+
+ /* src is allowed, target is forbidden */
+ assert(system("dd if=/dev/urandom of=/dev/full count=64"));
+
+ /* src is forbidden, target is allowed */
+ assert(system("dd if=/dev/random of=/dev/zero count=64"));
+
+ error = 0;
+ printf("test_dev_cgroup:PASS\n");
+
+err:
+ cleanup_cgroup_environment();
+
+ return error;
+}