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 12 /* Using CAP_LAST_CAP is risky here, since it can get pulled in from 13 * an old /usr/include/linux/capability.h and be < CAP_BPF; as a result 14 * CAP_BPF would not be included in ALL_CAPS. Instead use CAP_BPF as 15 * we know its value is correct since it is explicitly defined in 16 * cap_helpers.h. 17 */ 18 #define ALL_CAPS ((2ULL << CAP_BPF) - 1) 19 20 #define PINPATH "/sys/fs/bpf/unpriv_bpf_disabled_" 21 #define NUM_MAPS 7 22 23 static __u32 got_perfbuf_val; 24 static __u32 got_ringbuf_val; 25 26 static int process_ringbuf(void *ctx, void *data, size_t len) 27 { 28 if (ASSERT_EQ(len, sizeof(__u32), "ringbuf_size_valid")) 29 got_ringbuf_val = *(__u32 *)data; 30 return 0; 31 } 32 33 static void process_perfbuf(void *ctx, int cpu, void *data, __u32 len) 34 { 35 if (ASSERT_EQ(len, sizeof(__u32), "perfbuf_size_valid")) 36 got_perfbuf_val = *(__u32 *)data; 37 } 38 39 static int sysctl_set(const char *sysctl_path, char *old_val, const char *new_val) 40 { 41 int ret = 0; 42 FILE *fp; 43 44 fp = fopen(sysctl_path, "r+"); 45 if (!fp) 46 return -errno; 47 if (old_val && fscanf(fp, "%s", old_val) <= 0) { 48 ret = -ENOENT; 49 } else if (!old_val || strcmp(old_val, new_val) != 0) { 50 fseek(fp, 0, SEEK_SET); 51 if (fprintf(fp, "%s", new_val) < 0) 52 ret = -errno; 53 } 54 fclose(fp); 55 56 return ret; 57 } 58 59 static void test_unpriv_bpf_disabled_positive(struct test_unpriv_bpf_disabled *skel, 60 __u32 prog_id, int prog_fd, int perf_fd, 61 char **map_paths, int *map_fds) 62 { 63 struct perf_buffer *perfbuf = NULL; 64 struct ring_buffer *ringbuf = NULL; 65 int i, nr_cpus, link_fd = -1; 66 67 nr_cpus = bpf_num_possible_cpus(); 68 69 skel->bss->perfbuf_val = 1; 70 skel->bss->ringbuf_val = 2; 71 72 /* Positive tests for unprivileged BPF disabled. Verify we can 73 * - retrieve and interact with pinned maps; 74 * - set up and interact with perf buffer; 75 * - set up and interact with ring buffer; 76 * - create a link 77 */ 78 perfbuf = perf_buffer__new(bpf_map__fd(skel->maps.perfbuf), 8, process_perfbuf, NULL, NULL, 79 NULL); 80 if (!ASSERT_OK_PTR(perfbuf, "perf_buffer__new")) 81 goto cleanup; 82 83 ringbuf = ring_buffer__new(bpf_map__fd(skel->maps.ringbuf), process_ringbuf, NULL, NULL); 84 if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new")) 85 goto cleanup; 86 87 /* trigger & validate perf event, ringbuf output */ 88 usleep(1); 89 90 ASSERT_GT(perf_buffer__poll(perfbuf, 100), -1, "perf_buffer__poll"); 91 ASSERT_EQ(got_perfbuf_val, skel->bss->perfbuf_val, "check_perfbuf_val"); 92 ASSERT_EQ(ring_buffer__consume(ringbuf), 1, "ring_buffer__consume"); 93 ASSERT_EQ(got_ringbuf_val, skel->bss->ringbuf_val, "check_ringbuf_val"); 94 95 for (i = 0; i < NUM_MAPS; i++) { 96 map_fds[i] = bpf_obj_get(map_paths[i]); 97 if (!ASSERT_GT(map_fds[i], -1, "obj_get")) 98 goto cleanup; 99 } 100 101 for (i = 0; i < NUM_MAPS; i++) { 102 bool prog_array = strstr(map_paths[i], "prog_array") != NULL; 103 bool array = strstr(map_paths[i], "array") != NULL; 104 bool buf = strstr(map_paths[i], "buf") != NULL; 105 __u32 key = 0, vals[nr_cpus], lookup_vals[nr_cpus]; 106 __u32 expected_val = 1; 107 int j; 108 109 /* skip ringbuf, perfbuf */ 110 if (buf) 111 continue; 112 113 for (j = 0; j < nr_cpus; j++) 114 vals[j] = expected_val; 115 116 if (prog_array) { 117 /* need valid prog array value */ 118 vals[0] = prog_fd; 119 /* prog array lookup returns prog id, not fd */ 120 expected_val = prog_id; 121 } 122 ASSERT_OK(bpf_map_update_elem(map_fds[i], &key, vals, 0), "map_update_elem"); 123 ASSERT_OK(bpf_map_lookup_elem(map_fds[i], &key, &lookup_vals), "map_lookup_elem"); 124 ASSERT_EQ(lookup_vals[0], expected_val, "map_lookup_elem_values"); 125 if (!array) 126 ASSERT_OK(bpf_map_delete_elem(map_fds[i], &key), "map_delete_elem"); 127 } 128 129 link_fd = bpf_link_create(bpf_program__fd(skel->progs.handle_perf_event), perf_fd, 130 BPF_PERF_EVENT, NULL); 131 ASSERT_GT(link_fd, 0, "link_create"); 132 133 cleanup: 134 if (link_fd) 135 close(link_fd); 136 if (perfbuf) 137 perf_buffer__free(perfbuf); 138 if (ringbuf) 139 ring_buffer__free(ringbuf); 140 } 141 142 static void test_unpriv_bpf_disabled_negative(struct test_unpriv_bpf_disabled *skel, 143 __u32 prog_id, int prog_fd, int perf_fd, 144 char **map_paths, int *map_fds) 145 { 146 const struct bpf_insn prog_insns[] = { 147 BPF_MOV64_IMM(BPF_REG_0, 0), 148 BPF_EXIT_INSN(), 149 }; 150 const size_t prog_insn_cnt = ARRAY_SIZE(prog_insns); 151 LIBBPF_OPTS(bpf_prog_load_opts, load_opts); 152 struct bpf_map_info map_info = {}; 153 __u32 map_info_len = sizeof(map_info); 154 struct bpf_link_info link_info = {}; 155 __u32 link_info_len = sizeof(link_info); 156 struct btf *btf = NULL; 157 __u32 attach_flags = 0; 158 __u32 prog_ids[3] = {}; 159 __u32 prog_cnt = 3; 160 __u32 next; 161 int i; 162 163 /* Negative tests for unprivileged BPF disabled. Verify we cannot 164 * - load BPF programs; 165 * - create BPF maps; 166 * - get a prog/map/link fd by id; 167 * - get next prog/map/link id 168 * - query prog 169 * - BTF load 170 */ 171 ASSERT_EQ(bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "simple_prog", "GPL", 172 prog_insns, prog_insn_cnt, &load_opts), 173 -EPERM, "prog_load_fails"); 174 175 /* some map types require particular correct parameters which could be 176 * sanity-checked before enforcing -EPERM, so only validate that 177 * the simple ARRAY and HASH maps are failing with -EPERM 178 */ 179 for (i = BPF_MAP_TYPE_HASH; i <= BPF_MAP_TYPE_ARRAY; i++) 180 ASSERT_EQ(bpf_map_create(i, NULL, sizeof(int), sizeof(int), 1, NULL), 181 -EPERM, "map_create_fails"); 182 183 ASSERT_EQ(bpf_prog_get_fd_by_id(prog_id), -EPERM, "prog_get_fd_by_id_fails"); 184 ASSERT_EQ(bpf_prog_get_next_id(prog_id, &next), -EPERM, "prog_get_next_id_fails"); 185 ASSERT_EQ(bpf_prog_get_next_id(0, &next), -EPERM, "prog_get_next_id_fails"); 186 187 if (ASSERT_OK(bpf_map_get_info_by_fd(map_fds[0], &map_info, &map_info_len), 188 "obj_get_info_by_fd")) { 189 ASSERT_EQ(bpf_map_get_fd_by_id(map_info.id), -EPERM, "map_get_fd_by_id_fails"); 190 ASSERT_EQ(bpf_map_get_next_id(map_info.id, &next), -EPERM, 191 "map_get_next_id_fails"); 192 } 193 ASSERT_EQ(bpf_map_get_next_id(0, &next), -EPERM, "map_get_next_id_fails"); 194 195 if (ASSERT_OK(bpf_link_get_info_by_fd(bpf_link__fd(skel->links.sys_nanosleep_enter), 196 &link_info, &link_info_len), 197 "obj_get_info_by_fd")) { 198 ASSERT_EQ(bpf_link_get_fd_by_id(link_info.id), -EPERM, "link_get_fd_by_id_fails"); 199 ASSERT_EQ(bpf_link_get_next_id(link_info.id, &next), -EPERM, 200 "link_get_next_id_fails"); 201 } 202 ASSERT_EQ(bpf_link_get_next_id(0, &next), -EPERM, "link_get_next_id_fails"); 203 204 ASSERT_EQ(bpf_prog_query(prog_fd, BPF_TRACE_FENTRY, 0, &attach_flags, prog_ids, 205 &prog_cnt), -EPERM, "prog_query_fails"); 206 207 btf = btf__new_empty(); 208 if (ASSERT_OK_PTR(btf, "empty_btf") && 209 ASSERT_GT(btf__add_int(btf, "int", 4, 0), 0, "unpriv_int_type")) { 210 const void *raw_btf_data; 211 __u32 raw_btf_size; 212 213 raw_btf_data = btf__raw_data(btf, &raw_btf_size); 214 if (ASSERT_OK_PTR(raw_btf_data, "raw_btf_data_good")) 215 ASSERT_EQ(bpf_btf_load(raw_btf_data, raw_btf_size, NULL), -EPERM, 216 "bpf_btf_load_fails"); 217 } 218 btf__free(btf); 219 } 220 221 void test_unpriv_bpf_disabled(void) 222 { 223 char *map_paths[NUM_MAPS] = { PINPATH "array", 224 PINPATH "percpu_array", 225 PINPATH "hash", 226 PINPATH "percpu_hash", 227 PINPATH "perfbuf", 228 PINPATH "ringbuf", 229 PINPATH "prog_array" }; 230 int map_fds[NUM_MAPS]; 231 struct test_unpriv_bpf_disabled *skel; 232 char unprivileged_bpf_disabled_orig[32] = {}; 233 char perf_event_paranoid_orig[32] = {}; 234 struct bpf_prog_info prog_info = {}; 235 __u32 prog_info_len = sizeof(prog_info); 236 struct perf_event_attr attr = {}; 237 int prog_fd, perf_fd = -1, i, ret; 238 __u64 save_caps = 0; 239 __u32 prog_id; 240 241 skel = test_unpriv_bpf_disabled__open_and_load(); 242 if (!ASSERT_OK_PTR(skel, "skel_open")) 243 return; 244 245 skel->bss->test_pid = getpid(); 246 247 map_fds[0] = bpf_map__fd(skel->maps.array); 248 map_fds[1] = bpf_map__fd(skel->maps.percpu_array); 249 map_fds[2] = bpf_map__fd(skel->maps.hash); 250 map_fds[3] = bpf_map__fd(skel->maps.percpu_hash); 251 map_fds[4] = bpf_map__fd(skel->maps.perfbuf); 252 map_fds[5] = bpf_map__fd(skel->maps.ringbuf); 253 map_fds[6] = bpf_map__fd(skel->maps.prog_array); 254 255 for (i = 0; i < NUM_MAPS; i++) 256 ASSERT_OK(bpf_obj_pin(map_fds[i], map_paths[i]), "pin map_fd"); 257 258 /* allow user without caps to use perf events */ 259 if (!ASSERT_OK(sysctl_set("/proc/sys/kernel/perf_event_paranoid", perf_event_paranoid_orig, 260 "-1"), 261 "set_perf_event_paranoid")) 262 goto cleanup; 263 /* ensure unprivileged bpf disabled is set */ 264 ret = sysctl_set("/proc/sys/kernel/unprivileged_bpf_disabled", 265 unprivileged_bpf_disabled_orig, "2"); 266 if (ret == -EPERM) { 267 /* if unprivileged_bpf_disabled=1, we get -EPERM back; that's okay. */ 268 if (!ASSERT_OK(strcmp(unprivileged_bpf_disabled_orig, "1"), 269 "unprivileged_bpf_disabled_on")) 270 goto cleanup; 271 } else { 272 if (!ASSERT_OK(ret, "set unprivileged_bpf_disabled")) 273 goto cleanup; 274 } 275 276 prog_fd = bpf_program__fd(skel->progs.sys_nanosleep_enter); 277 ASSERT_OK(bpf_prog_get_info_by_fd(prog_fd, &prog_info, &prog_info_len), 278 "obj_get_info_by_fd"); 279 prog_id = prog_info.id; 280 ASSERT_GT(prog_id, 0, "valid_prog_id"); 281 282 attr.size = sizeof(attr); 283 attr.type = PERF_TYPE_SOFTWARE; 284 attr.config = PERF_COUNT_SW_CPU_CLOCK; 285 attr.freq = 1; 286 attr.sample_freq = 1000; 287 perf_fd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); 288 if (!ASSERT_GE(perf_fd, 0, "perf_fd")) 289 goto cleanup; 290 291 if (!ASSERT_OK(test_unpriv_bpf_disabled__attach(skel), "skel_attach")) 292 goto cleanup; 293 294 if (!ASSERT_OK(cap_disable_effective(ALL_CAPS, &save_caps), "disable caps")) 295 goto cleanup; 296 297 if (test__start_subtest("unpriv_bpf_disabled_positive")) 298 test_unpriv_bpf_disabled_positive(skel, prog_id, prog_fd, perf_fd, map_paths, 299 map_fds); 300 301 if (test__start_subtest("unpriv_bpf_disabled_negative")) 302 test_unpriv_bpf_disabled_negative(skel, prog_id, prog_fd, perf_fd, map_paths, 303 map_fds); 304 305 cleanup: 306 close(perf_fd); 307 if (save_caps) 308 cap_enable_effective(save_caps, NULL); 309 if (strlen(perf_event_paranoid_orig) > 0) 310 sysctl_set("/proc/sys/kernel/perf_event_paranoid", NULL, perf_event_paranoid_orig); 311 if (strlen(unprivileged_bpf_disabled_orig) > 0) 312 sysctl_set("/proc/sys/kernel/unprivileged_bpf_disabled", NULL, 313 unprivileged_bpf_disabled_orig); 314 for (i = 0; i < NUM_MAPS; i++) 315 unlink(map_paths[i]); 316 test_unpriv_bpf_disabled__destroy(skel); 317 } 318