| // SPDX-License-Identifier: GPL-2.0 |
| /* Copyright (c) 2022, Oracle and/or its affiliates. */ |
| |
| #include <test_progs.h> |
| #include <bpf/btf.h> |
| |
| #include "test_unpriv_bpf_disabled.skel.h" |
| |
| #include "cap_helpers.h" |
| |
| /* Using CAP_LAST_CAP is risky here, since it can get pulled in from |
| * an old /usr/include/linux/capability.h and be < CAP_BPF; as a result |
| * CAP_BPF would not be included in ALL_CAPS. Instead use CAP_BPF as |
| * we know its value is correct since it is explicitly defined in |
| * cap_helpers.h. |
| */ |
| #define ALL_CAPS ((2ULL << CAP_BPF) - 1) |
| |
| #define PINPATH "/sys/fs/bpf/unpriv_bpf_disabled_" |
| #define NUM_MAPS 7 |
| |
| static __u32 got_perfbuf_val; |
| static __u32 got_ringbuf_val; |
| |
| static int process_ringbuf(void *ctx, void *data, size_t len) |
| { |
| if (ASSERT_EQ(len, sizeof(__u32), "ringbuf_size_valid")) |
| got_ringbuf_val = *(__u32 *)data; |
| return 0; |
| } |
| |
| static void process_perfbuf(void *ctx, int cpu, void *data, __u32 len) |
| { |
| if (ASSERT_EQ(len, sizeof(__u32), "perfbuf_size_valid")) |
| got_perfbuf_val = *(__u32 *)data; |
| } |
| |
| static int sysctl_set(const char *sysctl_path, char *old_val, const char *new_val) |
| { |
| int ret = 0; |
| FILE *fp; |
| |
| fp = fopen(sysctl_path, "r+"); |
| if (!fp) |
| return -errno; |
| if (old_val && fscanf(fp, "%s", old_val) <= 0) { |
| ret = -ENOENT; |
| } else if (!old_val || strcmp(old_val, new_val) != 0) { |
| fseek(fp, 0, SEEK_SET); |
| if (fprintf(fp, "%s", new_val) < 0) |
| ret = -errno; |
| } |
| fclose(fp); |
| |
| return ret; |
| } |
| |
| static void test_unpriv_bpf_disabled_positive(struct test_unpriv_bpf_disabled *skel, |
| __u32 prog_id, int prog_fd, int perf_fd, |
| char **map_paths, int *map_fds) |
| { |
| struct perf_buffer *perfbuf = NULL; |
| struct ring_buffer *ringbuf = NULL; |
| int i, nr_cpus, link_fd = -1; |
| |
| nr_cpus = bpf_num_possible_cpus(); |
| |
| skel->bss->perfbuf_val = 1; |
| skel->bss->ringbuf_val = 2; |
| |
| /* Positive tests for unprivileged BPF disabled. Verify we can |
| * - retrieve and interact with pinned maps; |
| * - set up and interact with perf buffer; |
| * - set up and interact with ring buffer; |
| * - create a link |
| */ |
| perfbuf = perf_buffer__new(bpf_map__fd(skel->maps.perfbuf), 8, process_perfbuf, NULL, NULL, |
| NULL); |
| if (!ASSERT_OK_PTR(perfbuf, "perf_buffer__new")) |
| goto cleanup; |
| |
| ringbuf = ring_buffer__new(bpf_map__fd(skel->maps.ringbuf), process_ringbuf, NULL, NULL); |
| if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new")) |
| goto cleanup; |
| |
| /* trigger & validate perf event, ringbuf output */ |
| usleep(1); |
| |
| ASSERT_GT(perf_buffer__poll(perfbuf, 100), -1, "perf_buffer__poll"); |
| ASSERT_EQ(got_perfbuf_val, skel->bss->perfbuf_val, "check_perfbuf_val"); |
| ASSERT_EQ(ring_buffer__consume(ringbuf), 1, "ring_buffer__consume"); |
| ASSERT_EQ(got_ringbuf_val, skel->bss->ringbuf_val, "check_ringbuf_val"); |
| |
| for (i = 0; i < NUM_MAPS; i++) { |
| map_fds[i] = bpf_obj_get(map_paths[i]); |
| if (!ASSERT_GT(map_fds[i], -1, "obj_get")) |
| goto cleanup; |
| } |
| |
| for (i = 0; i < NUM_MAPS; i++) { |
| bool prog_array = strstr(map_paths[i], "prog_array") != NULL; |
| bool array = strstr(map_paths[i], "array") != NULL; |
| bool buf = strstr(map_paths[i], "buf") != NULL; |
| __u32 key = 0, vals[nr_cpus], lookup_vals[nr_cpus]; |
| __u32 expected_val = 1; |
| int j; |
| |
| /* skip ringbuf, perfbuf */ |
| if (buf) |
| continue; |
| |
| for (j = 0; j < nr_cpus; j++) |
| vals[j] = expected_val; |
| |
| if (prog_array) { |
| /* need valid prog array value */ |
| vals[0] = prog_fd; |
| /* prog array lookup returns prog id, not fd */ |
| expected_val = prog_id; |
| } |
| ASSERT_OK(bpf_map_update_elem(map_fds[i], &key, vals, 0), "map_update_elem"); |
| ASSERT_OK(bpf_map_lookup_elem(map_fds[i], &key, &lookup_vals), "map_lookup_elem"); |
| ASSERT_EQ(lookup_vals[0], expected_val, "map_lookup_elem_values"); |
| if (!array) |
| ASSERT_OK(bpf_map_delete_elem(map_fds[i], &key), "map_delete_elem"); |
| } |
| |
| link_fd = bpf_link_create(bpf_program__fd(skel->progs.handle_perf_event), perf_fd, |
| BPF_PERF_EVENT, NULL); |
| ASSERT_GT(link_fd, 0, "link_create"); |
| |
| cleanup: |
| if (link_fd) |
| close(link_fd); |
| if (perfbuf) |
| perf_buffer__free(perfbuf); |
| if (ringbuf) |
| ring_buffer__free(ringbuf); |
| } |
| |
| static void test_unpriv_bpf_disabled_negative(struct test_unpriv_bpf_disabled *skel, |
| __u32 prog_id, int prog_fd, int perf_fd, |
| char **map_paths, int *map_fds) |
| { |
| const struct bpf_insn prog_insns[] = { |
| BPF_MOV64_IMM(BPF_REG_0, 0), |
| BPF_EXIT_INSN(), |
| }; |
| const size_t prog_insn_cnt = sizeof(prog_insns) / sizeof(struct bpf_insn); |
| LIBBPF_OPTS(bpf_prog_load_opts, load_opts); |
| struct bpf_map_info map_info = {}; |
| __u32 map_info_len = sizeof(map_info); |
| struct bpf_link_info link_info = {}; |
| __u32 link_info_len = sizeof(link_info); |
| struct btf *btf = NULL; |
| __u32 attach_flags = 0; |
| __u32 prog_ids[3] = {}; |
| __u32 prog_cnt = 3; |
| __u32 next; |
| int i; |
| |
| /* Negative tests for unprivileged BPF disabled. Verify we cannot |
| * - load BPF programs; |
| * - create BPF maps; |
| * - get a prog/map/link fd by id; |
| * - get next prog/map/link id |
| * - query prog |
| * - BTF load |
| */ |
| ASSERT_EQ(bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "simple_prog", "GPL", |
| prog_insns, prog_insn_cnt, &load_opts), |
| -EPERM, "prog_load_fails"); |
| |
| for (i = BPF_MAP_TYPE_HASH; i <= BPF_MAP_TYPE_BLOOM_FILTER; i++) |
| ASSERT_EQ(bpf_map_create(i, NULL, sizeof(int), sizeof(int), 1, NULL), |
| -EPERM, "map_create_fails"); |
| |
| ASSERT_EQ(bpf_prog_get_fd_by_id(prog_id), -EPERM, "prog_get_fd_by_id_fails"); |
| ASSERT_EQ(bpf_prog_get_next_id(prog_id, &next), -EPERM, "prog_get_next_id_fails"); |
| ASSERT_EQ(bpf_prog_get_next_id(0, &next), -EPERM, "prog_get_next_id_fails"); |
| |
| if (ASSERT_OK(bpf_map_get_info_by_fd(map_fds[0], &map_info, &map_info_len), |
| "obj_get_info_by_fd")) { |
| ASSERT_EQ(bpf_map_get_fd_by_id(map_info.id), -EPERM, "map_get_fd_by_id_fails"); |
| ASSERT_EQ(bpf_map_get_next_id(map_info.id, &next), -EPERM, |
| "map_get_next_id_fails"); |
| } |
| ASSERT_EQ(bpf_map_get_next_id(0, &next), -EPERM, "map_get_next_id_fails"); |
| |
| if (ASSERT_OK(bpf_link_get_info_by_fd(bpf_link__fd(skel->links.sys_nanosleep_enter), |
| &link_info, &link_info_len), |
| "obj_get_info_by_fd")) { |
| ASSERT_EQ(bpf_link_get_fd_by_id(link_info.id), -EPERM, "link_get_fd_by_id_fails"); |
| ASSERT_EQ(bpf_link_get_next_id(link_info.id, &next), -EPERM, |
| "link_get_next_id_fails"); |
| } |
| ASSERT_EQ(bpf_link_get_next_id(0, &next), -EPERM, "link_get_next_id_fails"); |
| |
| ASSERT_EQ(bpf_prog_query(prog_fd, BPF_TRACE_FENTRY, 0, &attach_flags, prog_ids, |
| &prog_cnt), -EPERM, "prog_query_fails"); |
| |
| btf = btf__new_empty(); |
| if (ASSERT_OK_PTR(btf, "empty_btf") && |
| ASSERT_GT(btf__add_int(btf, "int", 4, 0), 0, "unpriv_int_type")) { |
| const void *raw_btf_data; |
| __u32 raw_btf_size; |
| |
| raw_btf_data = btf__raw_data(btf, &raw_btf_size); |
| if (ASSERT_OK_PTR(raw_btf_data, "raw_btf_data_good")) |
| ASSERT_EQ(bpf_btf_load(raw_btf_data, raw_btf_size, NULL), -EPERM, |
| "bpf_btf_load_fails"); |
| } |
| btf__free(btf); |
| } |
| |
| void test_unpriv_bpf_disabled(void) |
| { |
| char *map_paths[NUM_MAPS] = { PINPATH "array", |
| PINPATH "percpu_array", |
| PINPATH "hash", |
| PINPATH "percpu_hash", |
| PINPATH "perfbuf", |
| PINPATH "ringbuf", |
| PINPATH "prog_array" }; |
| int map_fds[NUM_MAPS]; |
| struct test_unpriv_bpf_disabled *skel; |
| char unprivileged_bpf_disabled_orig[32] = {}; |
| char perf_event_paranoid_orig[32] = {}; |
| struct bpf_prog_info prog_info = {}; |
| __u32 prog_info_len = sizeof(prog_info); |
| struct perf_event_attr attr = {}; |
| int prog_fd, perf_fd = -1, i, ret; |
| __u64 save_caps = 0; |
| __u32 prog_id; |
| |
| skel = test_unpriv_bpf_disabled__open_and_load(); |
| if (!ASSERT_OK_PTR(skel, "skel_open")) |
| return; |
| |
| skel->bss->test_pid = getpid(); |
| |
| map_fds[0] = bpf_map__fd(skel->maps.array); |
| map_fds[1] = bpf_map__fd(skel->maps.percpu_array); |
| map_fds[2] = bpf_map__fd(skel->maps.hash); |
| map_fds[3] = bpf_map__fd(skel->maps.percpu_hash); |
| map_fds[4] = bpf_map__fd(skel->maps.perfbuf); |
| map_fds[5] = bpf_map__fd(skel->maps.ringbuf); |
| map_fds[6] = bpf_map__fd(skel->maps.prog_array); |
| |
| for (i = 0; i < NUM_MAPS; i++) |
| ASSERT_OK(bpf_obj_pin(map_fds[i], map_paths[i]), "pin map_fd"); |
| |
| /* allow user without caps to use perf events */ |
| if (!ASSERT_OK(sysctl_set("/proc/sys/kernel/perf_event_paranoid", perf_event_paranoid_orig, |
| "-1"), |
| "set_perf_event_paranoid")) |
| goto cleanup; |
| /* ensure unprivileged bpf disabled is set */ |
| ret = sysctl_set("/proc/sys/kernel/unprivileged_bpf_disabled", |
| unprivileged_bpf_disabled_orig, "2"); |
| if (ret == -EPERM) { |
| /* if unprivileged_bpf_disabled=1, we get -EPERM back; that's okay. */ |
| if (!ASSERT_OK(strcmp(unprivileged_bpf_disabled_orig, "1"), |
| "unprivileged_bpf_disabled_on")) |
| goto cleanup; |
| } else { |
| if (!ASSERT_OK(ret, "set unprivileged_bpf_disabled")) |
| goto cleanup; |
| } |
| |
| prog_fd = bpf_program__fd(skel->progs.sys_nanosleep_enter); |
| ASSERT_OK(bpf_prog_get_info_by_fd(prog_fd, &prog_info, &prog_info_len), |
| "obj_get_info_by_fd"); |
| prog_id = prog_info.id; |
| ASSERT_GT(prog_id, 0, "valid_prog_id"); |
| |
| attr.size = sizeof(attr); |
| attr.type = PERF_TYPE_SOFTWARE; |
| attr.config = PERF_COUNT_SW_CPU_CLOCK; |
| attr.freq = 1; |
| attr.sample_freq = 1000; |
| perf_fd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); |
| if (!ASSERT_GE(perf_fd, 0, "perf_fd")) |
| goto cleanup; |
| |
| if (!ASSERT_OK(test_unpriv_bpf_disabled__attach(skel), "skel_attach")) |
| goto cleanup; |
| |
| if (!ASSERT_OK(cap_disable_effective(ALL_CAPS, &save_caps), "disable caps")) |
| goto cleanup; |
| |
| if (test__start_subtest("unpriv_bpf_disabled_positive")) |
| test_unpriv_bpf_disabled_positive(skel, prog_id, prog_fd, perf_fd, map_paths, |
| map_fds); |
| |
| if (test__start_subtest("unpriv_bpf_disabled_negative")) |
| test_unpriv_bpf_disabled_negative(skel, prog_id, prog_fd, perf_fd, map_paths, |
| map_fds); |
| |
| cleanup: |
| close(perf_fd); |
| if (save_caps) |
| cap_enable_effective(save_caps, NULL); |
| if (strlen(perf_event_paranoid_orig) > 0) |
| sysctl_set("/proc/sys/kernel/perf_event_paranoid", NULL, perf_event_paranoid_orig); |
| if (strlen(unprivileged_bpf_disabled_orig) > 0) |
| sysctl_set("/proc/sys/kernel/unprivileged_bpf_disabled", NULL, |
| unprivileged_bpf_disabled_orig); |
| for (i = 0; i < NUM_MAPS; i++) |
| unlink(map_paths[i]); |
| test_unpriv_bpf_disabled__destroy(skel); |
| } |