On 2/21/24 2:22 PM, Muhammad Usama Anjum wrote:

Move test_dev_cgroup.c to prog_tests/dev_cgroup.c to be able to run it with test_progs. Replace dev_cgroup.bpf.o with skel header file, dev_cgroup.skel.h and load program from it accourdingly.

./test_progs -t test_dev_cgroup mknod: /tmp/test_dev_cgroup_null: Operation not permitted 64+0 records in 64+0 records out 32768 bytes (33 kB, 32 KiB) copied, 0.000856684 s, 38.2 MB/s dd: failed to open '/dev/full': Operation not permitted dd: failed to open '/dev/random': Operation not permitted #365 test_dev_cgroup:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Muhammad Usama Anjum usama.anjum@collabora.com

I've tested the patch with vmtest.sh on bpf-next/for-next and linux next. It is passing on both. Not sure why it was failed on BPFCI. Test run with vmtest.h: sudo LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh ./test_progs -t dev_cgroup ./test_progs -t dev_cgroup mknod: /tmp/test_dev_cgroup_null: Operation not permitted 64+0 records in 64+0 records out 32768 bytes (33 kB, 32 KiB) copied, 0.000403432 s, 81.2 MB/s dd: failed to open '/dev/full': Operation not permitted dd: failed to open '/dev/random': Operation not permitted #69 dev_cgroup:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Locally this test passes, but fails on BPFCI: https://github.com/kernel-patches/bpf/actions/runs/7986809998/job/2180817830...

Changes since v1:

• Rename file from test_dev_cgroup.c to dev_cgroup.c
• Use ASSERT_* in-place of CHECK

---

.../selftests/bpf/prog_tests/dev_cgroup.c | 58 +++++++++++++ tools/testing/selftests/bpf/test_dev_cgroup.c | 85 ------------------- 2 files changed, 58 insertions(+), 85 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/dev_cgroup.c delete mode 100644 tools/testing/selftests/bpf/test_dev_cgroup.c

diff --git a/tools/testing/selftests/bpf/prog_tests/dev_cgroup.c b/tools/testing/selftests/bpf/prog_tests/dev_cgroup.c new file mode 100644 index 0000000000000..980b015a116ff --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/dev_cgroup.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2017 Facebook

• */

+#include <test_progs.h> +#include <time.h> +#include "cgroup_helpers.h" +#include "dev_cgroup.skel.h"

+#define TEST_CGROUP "/test-bpf-based-device-cgroup/"

+void test_dev_cgroup(void) +{

• struct dev_cgroup *skel;
• int cgroup_fd, err;
• __u32 prog_cnt;
• skel = dev_cgroup__open_and_load();
• if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))

• goto cleanup;
  

• cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
• if (!ASSERT_GT(cgroup_fd, 0, "cgroup_setup_and_join"))

• goto cleanup;
  

• err = bpf_prog_attach(bpf_program__fd(skel->progs.bpf_prog1), cgroup_fd,

• 	      BPF_CGROUP_DEVICE, 0);
  

• if (!ASSERT_EQ(err, 0, "bpf_attach"))

• goto cleanup;
  

• err = bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL, &prog_cnt);
• if (!ASSERT_EQ(err, 0, "bpf_query") || (!ASSERT_EQ(prog_cnt, 1, "bpf_query")))

• goto cleanup;
  

• /* All operations with /dev/zero and /dev/urandom are allowed,

• * everything else is forbidden.
  

• */
  

• ASSERT_EQ(system("rm -f /tmp/test_dev_cgroup_null"), 0, "rm");
• ASSERT_NEQ(system("mknod /tmp/test_dev_cgroup_null c 1 3"), 0, "mknod");
• ASSERT_EQ(system("rm -f /tmp/test_dev_cgroup_null"), 0, "rm");
• /* /dev/zero is whitelisted */
• ASSERT_EQ(system("rm -f /tmp/test_dev_cgroup_zero"), 0, "rm");
• ASSERT_EQ(system("mknod /tmp/test_dev_cgroup_zero c 1 5"), 0, "mknod");

Access to major number 1 and minor number 5 is allowed. The return code of 0 is expected, but on CI we are getting 256 which indicates error. mknod help page mentions the same:

An exit status of zero indicates success, and a nonzero value indicates

failure.

• ASSERT_EQ(system("rm -f /tmp/test_dev_cgroup_zero"), 0, "rm");
• ASSERT_EQ(system("dd if=/dev/urandom of=/dev/zero count=64"), 0, "dd");
• /* src is allowed, target is forbidden */
• ASSERT_NEQ(system("dd if=/dev/urandom of=/dev/full count=64"), 0, "dd");
• /* src is forbidden, target is allowed */
• ASSERT_NEQ(system("dd if=/dev/random of=/dev/zero count=64"), 0, "dd");

+cleanup:

• cleanup_cgroup_environment();
• dev_cgroup__destroy(skel);

+} diff --git a/tools/testing/selftests/bpf/test_dev_cgroup.c b/tools/testing/selftests/bpf/test_dev_cgroup.c deleted file mode 100644 index adeaf63cb6fa3..0000000000000 --- a/tools/testing/selftests/bpf/test_dev_cgroup.c +++ /dev/null @@ -1,85 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* Copyright (c) 2017 Facebook

• */

-#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <errno.h> -#include <assert.h> -#include <sys/time.h>

-#include <linux/bpf.h> -#include <bpf/bpf.h> -#include <bpf/libbpf.h>

-#include "cgroup_helpers.h" -#include "testing_helpers.h"

-#define DEV_CGROUP_PROG "./dev_cgroup.bpf.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;
• /* Use libbpf 1.0 API mode */
• libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
• if (bpf_prog_test_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,

• 	  &obj, &prog_fd)) {
  

• printf("Failed to load DEV_CGROUP program\n");
  

• goto out;
  

• }
• cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
• if (cgroup_fd < 0) {

• printf("Failed to create test cgroup\n");
  

• goto out;
  

• }
• /* 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();

-out:

• return error;

-}