src/test/test-bpf-firewall.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <linux/bpf_insn.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6
   7 #include "bpf-firewall.h"
   8 #include "bpf-program.h"
   9 #include "load-fragment.h"
  10 #include "manager.h"
  11 #include "rm-rf.h"
  12 #include "service.h"
  13 #include "tests.h"
  14 #include "unit.h"
  15 #include "virt.h"
  16
  17 int main(int argc, char *argv[]) {
  18         const struct bpf_insn exit_insn[] = {
  19                 BPF_MOV64_IMM(BPF_REG_0, 0), /* drop */
  20                 BPF_EXIT_INSN()
  21         };
  22
  23         _cleanup_(rm_rf_physical_and_freep) char *runtime_dir = NULL;
  24         CGroupContext *cc = NULL;
  25         _cleanup_(bpf_program_unrefp) BPFProgram *p = NULL;
  26         _cleanup_(manager_freep) Manager *m = NULL;
  27         Unit *u;
  28         char log_buf[65535];
  29         struct rlimit rl;
  30         int r;
  31         union bpf_attr attr;
  32         bool test_custom_filter = false;
  33         const char *test_prog = "/sys/fs/bpf/test-dropper";
  34
  35         test_setup_logging(LOG_DEBUG);
  36
  37         if (detect_container() > 0)
  38                 return log_tests_skipped("test-bpf-firewall fails inside LXC and Docker containers: https://github.com/systemd/systemd/issues/9666");
  39
  40         assert_se(getrlimit(RLIMIT_MEMLOCK, &rl) >= 0);
  41         rl.rlim_cur = rl.rlim_max = MAX(rl.rlim_max, CAN_MEMLOCK_SIZE);
  42         (void) setrlimit(RLIMIT_MEMLOCK, &rl);
  43
  44         if (!can_memlock())
  45                 return log_tests_skipped("Can't use mlock()");
  46
  47         r = enter_cgroup_subroot(NULL);
  48         if (r == -ENOMEDIUM)
  49                 return log_tests_skipped("cgroupfs not available");
  50
  51         _cleanup_free_ char *unit_dir = NULL;
  52         assert_se(get_testdata_dir("units", &unit_dir) >= 0);
  53         assert_se(set_unit_path(unit_dir) >= 0);
  54         assert_se(runtime_dir = setup_fake_runtime_dir());
  55
  56         r = bpf_program_new(BPF_PROG_TYPE_CGROUP_SKB, &p);
  57         assert(r == 0);
  58
  59         r = bpf_program_add_instructions(p, exit_insn, ELEMENTSOF(exit_insn));
  60         assert(r == 0);
  61
  62         if (getuid() != 0)
  63                 return log_tests_skipped("not running as root");
  64
  65         r = bpf_firewall_supported();
  66         if (r == BPF_FIREWALL_UNSUPPORTED)
  67                 return log_tests_skipped("BPF firewalling not supported");
  68         assert_se(r > 0);
  69
  70         if (r == BPF_FIREWALL_SUPPORTED_WITH_MULTI) {
  71                 log_notice("BPF firewalling with BPF_F_ALLOW_MULTI supported. Yay!");
  72                 test_custom_filter = true;
  73         } else
  74                 log_notice("BPF firewalling (though without BPF_F_ALLOW_MULTI) supported. Good.");
  75
  76         r = bpf_program_load_kernel(p, log_buf, ELEMENTSOF(log_buf));
  77         assert(r >= 0);
  78
  79         if (test_custom_filter) {
  80                 attr = (union bpf_attr) {
  81                         .pathname = PTR_TO_UINT64(test_prog),
  82                         .bpf_fd = p->kernel_fd,
  83                         .file_flags = 0,
  84                 };
  85
  86                 (void) unlink(test_prog);
  87
  88                 r = bpf(BPF_OBJ_PIN, &attr, sizeof(attr));
  89                 if (r < 0) {
  90                         log_warning_errno(errno, "BPF object pinning failed, will not run custom filter test: %m");
  91                         test_custom_filter = false;
  92                 }
  93         }
  94
  95         p = bpf_program_unref(p);
  96
  97         /* The simple tests succeeded. Now let's try full unit-based use-case. */
  98
  99         assert_se(manager_new(UNIT_FILE_USER, MANAGER_TEST_RUN_BASIC, &m) >= 0);
 100         assert_se(manager_startup(m, NULL, NULL) >= 0);
 101
 102         assert_se(u = unit_new(m, sizeof(Service)));
 103         assert_se(unit_add_name(u, "foo.service") == 0);
 104         assert_se(cc = unit_get_cgroup_context(u));
 105         u->perpetual = true;
 106
 107         cc->ip_accounting = true;
 108
 109         assert_se(config_parse_ip_address_access(u->id, "filename", 1, "Service", 1, "IPAddressAllow", 0, "10.0.1.0/24", &cc->ip_address_allow, NULL) == 0);
 110         assert_se(config_parse_ip_address_access(u->id, "filename", 1, "Service", 1, "IPAddressAllow", 0, "127.0.0.2", &cc->ip_address_allow, NULL) == 0);
 111         assert_se(config_parse_ip_address_access(u->id, "filename", 1, "Service", 1, "IPAddressDeny", 0, "127.0.0.3", &cc->ip_address_deny, NULL) == 0);
 112         assert_se(config_parse_ip_address_access(u->id, "filename", 1, "Service", 1, "IPAddressDeny", 0, "10.0.3.2/24", &cc->ip_address_deny, NULL) == 0);
 113         assert_se(config_parse_ip_address_access(u->id, "filename", 1, "Service", 1, "IPAddressDeny", 0, "127.0.0.1/25", &cc->ip_address_deny, NULL) == 0);
 114         assert_se(config_parse_ip_address_access(u->id, "filename", 1, "Service", 1, "IPAddressDeny", 0, "127.0.0.4", &cc->ip_address_deny, NULL) == 0);
 115
 116         assert(cc->ip_address_allow);
 117         assert(cc->ip_address_allow->items_next);
 118         assert(!cc->ip_address_allow->items_next->items_next);
 119
 120         /* The deny list is defined redundantly, let's ensure it got properly reduced */
 121         assert(cc->ip_address_deny);
 122         assert(cc->ip_address_deny->items_next);
 123         assert(!cc->ip_address_deny->items_next->items_next);
 124
 125         assert_se(config_parse_exec(u->id, "filename", 1, "Service", 1, "ExecStart", SERVICE_EXEC_START, "/bin/ping -c 1 127.0.0.2 -W 5", SERVICE(u)->exec_command, u) == 0);
 126         assert_se(config_parse_exec(u->id, "filename", 1, "Service", 1, "ExecStart", SERVICE_EXEC_START, "/bin/ping -c 1 127.0.0.3 -W 5", SERVICE(u)->exec_command, u) == 0);
 127
 128         assert_se(SERVICE(u)->exec_command[SERVICE_EXEC_START]);
 129         assert_se(SERVICE(u)->exec_command[SERVICE_EXEC_START]->command_next);
 130         assert_se(!SERVICE(u)->exec_command[SERVICE_EXEC_START]->command_next->command_next);
 131
 132         SERVICE(u)->type = SERVICE_ONESHOT;
 133         u->load_state = UNIT_LOADED;
 134
 135         unit_dump(u, stdout, NULL);
 136
 137         r = bpf_firewall_compile(u);
 138         if (IN_SET(r, -ENOTTY, -ENOSYS, -EPERM))
 139                 return log_tests_skipped("Kernel doesn't support the necessary bpf bits (masked out via seccomp?)");
 140         assert_se(r >= 0);
 141
 142         assert(u->ip_bpf_ingress);
 143         assert(u->ip_bpf_egress);
 144
 145         r = bpf_program_load_kernel(u->ip_bpf_ingress, log_buf, ELEMENTSOF(log_buf));
 146
 147         log_notice("log:");
 148         log_notice("-------");
 149         log_notice("%s", log_buf);
 150         log_notice("-------");
 151
 152         assert(r >= 0);
 153
 154         r = bpf_program_load_kernel(u->ip_bpf_egress, log_buf, ELEMENTSOF(log_buf));
 155
 156         log_notice("log:");
 157         log_notice("-------");
 158         log_notice("%s", log_buf);
 159         log_notice("-------");
 160
 161         assert(r >= 0);
 162
 163         assert_se(unit_start(u) >= 0);
 164
 165         while (!IN_SET(SERVICE(u)->state, SERVICE_DEAD, SERVICE_FAILED))
 166                 assert_se(sd_event_run(m->event, UINT64_MAX) >= 0);
 167
 168         assert_se(SERVICE(u)->exec_command[SERVICE_EXEC_START]->exec_status.code == CLD_EXITED &&
 169                   SERVICE(u)->exec_command[SERVICE_EXEC_START]->exec_status.status == EXIT_SUCCESS);
 170
 171         assert_se(SERVICE(u)->exec_command[SERVICE_EXEC_START]->command_next->exec_status.code != CLD_EXITED ||
 172                   SERVICE(u)->exec_command[SERVICE_EXEC_START]->command_next->exec_status.status != EXIT_SUCCESS);
 173
 174         if (test_custom_filter) {
 175                 assert_se(u = unit_new(m, sizeof(Service)));
 176                 assert_se(unit_add_name(u, "custom-filter.service") == 0);
 177                 assert_se(cc = unit_get_cgroup_context(u));
 178                 u->perpetual = true;
 179
 180                 cc->ip_accounting = true;
 181
 182                 assert_se(config_parse_ip_filter_bpf_progs(u->id, "filename", 1, "Service", 1, "IPIngressFilterPath", 0, test_prog, &cc->ip_filters_ingress, u) == 0);
 183                 assert_se(config_parse_exec(u->id, "filename", 1, "Service", 1, "ExecStart", SERVICE_EXEC_START, "-/bin/ping -c 1 127.0.0.1 -W 5", SERVICE(u)->exec_command, u) == 0);
 184
 185                 SERVICE(u)->type = SERVICE_ONESHOT;
 186                 u->load_state = UNIT_LOADED;
 187
 188                 assert_se(unit_start(u) >= 0);
 189
 190                 while (!IN_SET(SERVICE(u)->state, SERVICE_DEAD, SERVICE_FAILED))
 191                         assert_se(sd_event_run(m->event, UINT64_MAX) >= 0);
 192
 193                 assert_se(SERVICE(u)->exec_command[SERVICE_EXEC_START]->exec_status.code != CLD_EXITED ||
 194                           SERVICE(u)->exec_command[SERVICE_EXEC_START]->exec_status.status != EXIT_SUCCESS);
 195
 196                 (void) unlink(test_prog);
 197                 assert_se(SERVICE(u)->state == SERVICE_DEAD);
 198         }
 199
 200         return 0;
 201 }