tools/testing/selftests/bpf/prog_tests/cgroup_dev.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <sys/stat.h>
   4 #include <sys/sysmacros.h>
   5 #include <errno.h>
   6 #include "test_progs.h"
   7 #include "cgroup_helpers.h"
   8 #include "dev_cgroup.skel.h"
   9
  10 #define TEST_CGROUP "/test-bpf-based-device-cgroup/"
  11 #define TEST_BUFFER_SIZE 64
  12
  13 static void test_mknod(const char *path, mode_t mode, int dev_major,
  14                        int dev_minor, int expected_ret, int expected_errno)
  15 {
  16         int ret;
  17
  18         unlink(path);
  19         ret = mknod(path, mode, makedev(dev_major, dev_minor));
  20         ASSERT_EQ(ret, expected_ret, "mknod");
  21         if (expected_ret)
  22                 ASSERT_EQ(errno, expected_errno, "mknod errno");
  23         else
  24                 unlink(path);
  25 }
  26
  27 static void test_read(const char *path, char *buf, int buf_size,
  28                       int expected_ret, int expected_errno)
  29 {
  30         int ret, fd;
  31
  32         fd = open(path, O_RDONLY);
  33
  34         /* A bare open on unauthorized device should fail */
  35         if (expected_ret < 0) {
  36                 ASSERT_EQ(fd, expected_ret, "open ret for read");
  37                 ASSERT_EQ(errno, expected_errno, "open errno for read");
  38                 if (fd >= 0)
  39                         close(fd);
  40                 return;
  41         }
  42
  43         if (!ASSERT_OK_FD(fd, "open ret for read"))
  44                 return;
  45
  46         ret = read(fd, buf, buf_size);
  47         ASSERT_EQ(ret, expected_ret, "read");
  48
  49         close(fd);
  50 }
  51
  52 static void test_write(const char *path, char *buf, int buf_size,
  53                        int expected_ret, int expected_errno)
  54 {
  55         int ret, fd;
  56
  57         fd = open(path, O_WRONLY);
  58
  59         /* A bare open on unauthorized device should fail */
  60         if (expected_ret < 0) {
  61                 ASSERT_EQ(fd, expected_ret, "open ret for write");
  62                 ASSERT_EQ(errno, expected_errno, "open errno for write");
  63                 if (fd >= 0)
  64                         close(fd);
  65                 return;
  66         }
  67
  68         if (!ASSERT_OK_FD(fd, "open ret for write"))
  69                 return;
  70
  71         ret = write(fd, buf, buf_size);
  72         ASSERT_EQ(ret, expected_ret, "write");
  73
  74         close(fd);
  75 }
  76
  77 void test_cgroup_dev(void)
  78 {
  79         char buf[TEST_BUFFER_SIZE] = "some random test data";
  80         struct dev_cgroup *skel;
  81         int cgroup_fd;
  82
  83         cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
  84         if (!ASSERT_OK_FD(cgroup_fd, "cgroup switch"))
  85                 return;
  86
  87         skel = dev_cgroup__open_and_load();
  88         if (!ASSERT_OK_PTR(skel, "load program"))
  89                 goto cleanup_cgroup;
  90
  91         skel->links.bpf_prog1 =
  92                 bpf_program__attach_cgroup(skel->progs.bpf_prog1, cgroup_fd);
  93         if (!ASSERT_OK_PTR(skel->links.bpf_prog1, "attach_program"))
  94                 goto cleanup_progs;
  95
  96         if (test__start_subtest("allow-mknod"))
  97                 test_mknod("/dev/test_dev_cgroup_null", S_IFCHR, 1, 3, 0, 0);
  98
  99         if (test__start_subtest("allow-read"))
 100                 test_read("/dev/urandom", buf, TEST_BUFFER_SIZE,
 101                           TEST_BUFFER_SIZE, 0);
 102
 103         if (test__start_subtest("allow-write"))
 104                 test_write("/dev/null", buf, TEST_BUFFER_SIZE,
 105                            TEST_BUFFER_SIZE, 0);
 106
 107         if (test__start_subtest("deny-mknod"))
 108                 test_mknod("/dev/test_dev_cgroup_zero", S_IFCHR, 1, 5, -1,
 109                            EPERM);
 110
 111         if (test__start_subtest("deny-read"))
 112                 test_read("/dev/random", buf, TEST_BUFFER_SIZE, -1, EPERM);
 113
 114         if (test__start_subtest("deny-write"))
 115                 test_write("/dev/zero", buf, TEST_BUFFER_SIZE, -1, EPERM);
 116
 117         if (test__start_subtest("deny-mknod-wrong-type"))
 118                 test_mknod("/dev/test_dev_cgroup_block", S_IFBLK, 1, 3, -1,
 119                            EPERM);
 120
 121 cleanup_progs:
 122         dev_cgroup__destroy(skel);
 123 cleanup_cgroup:
 124         cleanup_cgroup_environment();
 125 }