1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2022, Oracle and/or its affiliates. */ 3 4 #include <test_progs.h> 5 #include <bpf/btf.h> 6 7 #include "test_unpriv_bpf_disabled.skel.h" 8 9 #include "cap_helpers.h" 10 #include "bpf_util.h" 11 #include "sysctl_helpers.h" 12 13 /* Using CAP_LAST_CAP is risky here, since it can get pulled in from 14 * an old /usr/include/linux/capability.h and be < CAP_BPF; as a result 15 * CAP_BPF would not be included in ALL_CAPS. Instead use CAP_BPF as 16 * we know its value is correct since it is explicitly defined in 17 * cap_helpers.h. 18 */ 19 #define ALL_CAPS ((2ULL << CAP_BPF) - 1) 20 21 #define PINPATH "/sys/fs/bpf/unpriv_bpf_disabled_" 22 #define NUM_MAPS 7 23 24 static __u32 got_perfbuf_val; 25 static __u32 got_ringbuf_val; 26 27 static int process_ringbuf(void *ctx, void *data, size_t len) 28 { 29 if (ASSERT_EQ(len, sizeof(__u32), "ringbuf_size_valid")) 30 got_ringbuf_val = *(__u32 *)data; 31 return 0; 32 } 33 34 static void process_perfbuf(void *ctx, int cpu, void *data, __u32 len) 35 { 36 if (ASSERT_EQ(len, sizeof(__u32), "perfbuf_size_valid")) 37 got_perfbuf_val = *(__u32 *)data; 38 } 39 40 static void test_unpriv_bpf_disabled_positive(struct test_unpriv_bpf_disabled *skel, 41 __u32 prog_id, int prog_fd, int perf_fd, 42 char **map_paths, int *map_fds) 43 { 44 struct perf_buffer *perfbuf = NULL; 45 struct ring_buffer *ringbuf = NULL; 46 int i, nr_cpus, link_fd = -1; 47 48 nr_cpus = bpf_num_possible_cpus(); 49 50 skel->bss->perfbuf_val = 1; 51 skel->bss->ringbuf_val = 2; 52 53 /* Positive tests for unprivileged BPF disabled. Verify we can 54 * - retrieve and interact with pinned maps; 55 * - set up and interact with perf buffer; 56 * - set up and interact with ring buffer; 57 * - create a link 58 */ 59 perfbuf = perf_buffer__new(bpf_map__fd(skel->maps.perfbuf), 8, process_perfbuf, NULL, NULL, 60 NULL); 61 if (!ASSERT_OK_PTR(perfbuf, "perf_buffer__new")) 62 goto cleanup; 63 64 ringbuf = ring_buffer__new(bpf_map__fd(skel->maps.ringbuf), process_ringbuf, NULL, NULL); 65 if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new")) 66 goto cleanup; 67 68 /* trigger & validate perf event, ringbuf output */ 69 usleep(1); 70 71 ASSERT_GT(perf_buffer__poll(perfbuf, 100), -1, "perf_buffer__poll"); 72 ASSERT_EQ(got_perfbuf_val, skel->bss->perfbuf_val, "check_perfbuf_val"); 73 ASSERT_EQ(ring_buffer__consume(ringbuf), 1, "ring_buffer__consume"); 74 ASSERT_EQ(got_ringbuf_val, skel->bss->ringbuf_val, "check_ringbuf_val"); 75 76 for (i = 0; i < NUM_MAPS; i++) { 77 map_fds[i] = bpf_obj_get(map_paths[i]); 78 if (!ASSERT_GT(map_fds[i], -1, "obj_get")) 79 goto cleanup; 80 } 81 82 for (i = 0; i < NUM_MAPS; i++) { 83 bool prog_array = strstr(map_paths[i], "prog_array") != NULL; 84 bool array = strstr(map_paths[i], "array") != NULL; 85 bool buf = strstr(map_paths[i], "buf") != NULL; 86 __u32 key = 0, vals[nr_cpus], lookup_vals[nr_cpus]; 87 __u32 expected_val = 1; 88 int j; 89 90 /* skip ringbuf, perfbuf */ 91 if (buf) 92 continue; 93 94 for (j = 0; j < nr_cpus; j++) 95 vals[j] = expected_val; 96 97 if (prog_array) { 98 /* need valid prog array value */ 99 vals[0] = prog_fd; 100 /* prog array lookup returns prog id, not fd */ 101 expected_val = prog_id; 102 } 103 ASSERT_OK(bpf_map_update_elem(map_fds[i], &key, vals, 0), "map_update_elem"); 104 ASSERT_OK(bpf_map_lookup_elem(map_fds[i], &key, &lookup_vals), "map_lookup_elem"); 105 ASSERT_EQ(lookup_vals[0], expected_val, "map_lookup_elem_values"); 106 if (!array) 107 ASSERT_OK(bpf_map_delete_elem(map_fds[i], &key), "map_delete_elem"); 108 } 109 110 link_fd = bpf_link_create(bpf_program__fd(skel->progs.handle_perf_event), perf_fd, 111 BPF_PERF_EVENT, NULL); 112 ASSERT_GT(link_fd, 0, "link_create"); 113 114 cleanup: 115 if (link_fd) 116 close(link_fd); 117 if (perfbuf) 118 perf_buffer__free(perfbuf); 119 if (ringbuf) 120 ring_buffer__free(ringbuf); 121 } 122 123 static void test_unpriv_bpf_disabled_negative(struct test_unpriv_bpf_disabled *skel, 124 __u32 prog_id, int prog_fd, int perf_fd, 125 char **map_paths, int *map_fds) 126 { 127 const struct bpf_insn prog_insns[] = { 128 BPF_MOV64_IMM(BPF_REG_0, 0), 129 BPF_EXIT_INSN(), 130 }; 131 const size_t prog_insn_cnt = ARRAY_SIZE(prog_insns); 132 LIBBPF_OPTS(bpf_prog_load_opts, load_opts); 133 struct bpf_map_info map_info = {}; 134 __u32 map_info_len = sizeof(map_info); 135 struct bpf_link_info link_info = {}; 136 __u32 link_info_len = sizeof(link_info); 137 struct btf *btf = NULL; 138 __u32 attach_flags = 0; 139 __u32 prog_ids[3] = {}; 140 __u32 prog_cnt = 3; 141 __u32 next; 142 int i; 143 144 /* Negative tests for unprivileged BPF disabled. Verify we cannot 145 * - load BPF programs; 146 * - create BPF maps; 147 * - get a prog/map/link fd by id; 148 * - get next prog/map/link id 149 * - query prog 150 * - BTF load 151 */ 152 ASSERT_EQ(bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "simple_prog", "GPL", 153 prog_insns, prog_insn_cnt, &load_opts), 154 -EPERM, "prog_load_fails"); 155 156 /* some map types require particular correct parameters which could be 157 * sanity-checked before enforcing -EPERM, so only validate that 158 * the simple ARRAY and HASH maps are failing with -EPERM 159 */ 160 for (i = BPF_MAP_TYPE_HASH; i <= BPF_MAP_TYPE_ARRAY; i++) 161 ASSERT_EQ(bpf_map_create(i, NULL, sizeof(int), sizeof(int), 1, NULL), 162 -EPERM, "map_create_fails"); 163 164 ASSERT_EQ(bpf_prog_get_fd_by_id(prog_id), -EPERM, "prog_get_fd_by_id_fails"); 165 ASSERT_EQ(bpf_prog_get_next_id(prog_id, &next), -EPERM, "prog_get_next_id_fails"); 166 ASSERT_EQ(bpf_prog_get_next_id(0, &next), -EPERM, "prog_get_next_id_fails"); 167 168 if (ASSERT_OK(bpf_map_get_info_by_fd(map_fds[0], &map_info, &map_info_len), 169 "obj_get_info_by_fd")) { 170 ASSERT_EQ(bpf_map_get_fd_by_id(map_info.id), -EPERM, "map_get_fd_by_id_fails"); 171 ASSERT_EQ(bpf_map_get_next_id(map_info.id, &next), -EPERM, 172 "map_get_next_id_fails"); 173 } 174 ASSERT_EQ(bpf_map_get_next_id(0, &next), -EPERM, "map_get_next_id_fails"); 175 176 if (ASSERT_OK(bpf_link_get_info_by_fd(bpf_link__fd(skel->links.sys_nanosleep_enter), 177 &link_info, &link_info_len), 178 "obj_get_info_by_fd")) { 179 ASSERT_EQ(bpf_link_get_fd_by_id(link_info.id), -EPERM, "link_get_fd_by_id_fails"); 180 ASSERT_EQ(bpf_link_get_next_id(link_info.id, &next), -EPERM, 181 "link_get_next_id_fails"); 182 } 183 ASSERT_EQ(bpf_link_get_next_id(0, &next), -EPERM, "link_get_next_id_fails"); 184 185 ASSERT_EQ(bpf_prog_query(prog_fd, BPF_TRACE_FENTRY, 0, &attach_flags, prog_ids, 186 &prog_cnt), -EPERM, "prog_query_fails"); 187 188 btf = btf__new_empty(); 189 if (ASSERT_OK_PTR(btf, "empty_btf") && 190 ASSERT_GT(btf__add_int(btf, "int", 4, 0), 0, "unpriv_int_type")) { 191 const void *raw_btf_data; 192 __u32 raw_btf_size; 193 194 raw_btf_data = btf__raw_data(btf, &raw_btf_size); 195 if (ASSERT_OK_PTR(raw_btf_data, "raw_btf_data_good")) 196 ASSERT_EQ(bpf_btf_load(raw_btf_data, raw_btf_size, NULL), -EPERM, 197 "bpf_btf_load_fails"); 198 } 199 btf__free(btf); 200 } 201 202 void test_unpriv_bpf_disabled(void) 203 { 204 char *map_paths[NUM_MAPS] = { PINPATH "array", 205 PINPATH "percpu_array", 206 PINPATH "hash", 207 PINPATH "percpu_hash", 208 PINPATH "perfbuf", 209 PINPATH "ringbuf", 210 PINPATH "prog_array" }; 211 int map_fds[NUM_MAPS]; 212 struct test_unpriv_bpf_disabled *skel; 213 char unprivileged_bpf_disabled_orig[32] = {}; 214 char perf_event_paranoid_orig[32] = {}; 215 struct bpf_prog_info prog_info = {}; 216 __u32 prog_info_len = sizeof(prog_info); 217 struct perf_event_attr attr = {}; 218 int prog_fd, perf_fd = -1, i, ret; 219 __u64 save_caps = 0; 220 __u32 prog_id; 221 222 skel = test_unpriv_bpf_disabled__open_and_load(); 223 if (!ASSERT_OK_PTR(skel, "skel_open")) 224 return; 225 226 skel->bss->test_pid = getpid(); 227 228 map_fds[0] = bpf_map__fd(skel->maps.array); 229 map_fds[1] = bpf_map__fd(skel->maps.percpu_array); 230 map_fds[2] = bpf_map__fd(skel->maps.hash); 231 map_fds[3] = bpf_map__fd(skel->maps.percpu_hash); 232 map_fds[4] = bpf_map__fd(skel->maps.perfbuf); 233 map_fds[5] = bpf_map__fd(skel->maps.ringbuf); 234 map_fds[6] = bpf_map__fd(skel->maps.prog_array); 235 236 for (i = 0; i < NUM_MAPS; i++) 237 ASSERT_OK(bpf_obj_pin(map_fds[i], map_paths[i]), "pin map_fd"); 238 239 /* allow user without caps to use perf events */ 240 if (!ASSERT_OK(sysctl_set("/proc/sys/kernel/perf_event_paranoid", perf_event_paranoid_orig, 241 "-1"), 242 "set_perf_event_paranoid")) 243 goto cleanup; 244 /* ensure unprivileged bpf disabled is set */ 245 ret = sysctl_set("/proc/sys/kernel/unprivileged_bpf_disabled", 246 unprivileged_bpf_disabled_orig, "2"); 247 if (ret == -EPERM) { 248 /* if unprivileged_bpf_disabled=1, we get -EPERM back; that's okay. */ 249 if (!ASSERT_OK(strcmp(unprivileged_bpf_disabled_orig, "1"), 250 "unprivileged_bpf_disabled_on")) 251 goto cleanup; 252 } else { 253 if (!ASSERT_OK(ret, "set unprivileged_bpf_disabled")) 254 goto cleanup; 255 } 256 257 prog_fd = bpf_program__fd(skel->progs.sys_nanosleep_enter); 258 ASSERT_OK(bpf_prog_get_info_by_fd(prog_fd, &prog_info, &prog_info_len), 259 "obj_get_info_by_fd"); 260 prog_id = prog_info.id; 261 ASSERT_GT(prog_id, 0, "valid_prog_id"); 262 263 attr.size = sizeof(attr); 264 attr.type = PERF_TYPE_SOFTWARE; 265 attr.config = PERF_COUNT_SW_CPU_CLOCK; 266 attr.freq = 1; 267 attr.sample_freq = 1000; 268 perf_fd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); 269 if (!ASSERT_GE(perf_fd, 0, "perf_fd")) 270 goto cleanup; 271 272 if (!ASSERT_OK(test_unpriv_bpf_disabled__attach(skel), "skel_attach")) 273 goto cleanup; 274 275 if (!ASSERT_OK(cap_disable_effective(ALL_CAPS, &save_caps), "disable caps")) 276 goto cleanup; 277 278 if (test__start_subtest("unpriv_bpf_disabled_positive")) 279 test_unpriv_bpf_disabled_positive(skel, prog_id, prog_fd, perf_fd, map_paths, 280 map_fds); 281 282 if (test__start_subtest("unpriv_bpf_disabled_negative")) 283 test_unpriv_bpf_disabled_negative(skel, prog_id, prog_fd, perf_fd, map_paths, 284 map_fds); 285 286 cleanup: 287 close(perf_fd); 288 if (save_caps) 289 cap_enable_effective(save_caps, NULL); 290 if (strlen(perf_event_paranoid_orig) > 0) 291 sysctl_set("/proc/sys/kernel/perf_event_paranoid", NULL, perf_event_paranoid_orig); 292 if (strlen(unprivileged_bpf_disabled_orig) > 0) 293 sysctl_set("/proc/sys/kernel/unprivileged_bpf_disabled", NULL, 294 unprivileged_bpf_disabled_orig); 295 for (i = 0; i < NUM_MAPS; i++) 296 unlink(map_paths[i]); 297 test_unpriv_bpf_disabled__destroy(skel); 298 } 299