diff options
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/unpriv_bpf_disabled.c')
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/unpriv_bpf_disabled.c | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/unpriv_bpf_disabled.c b/tools/testing/selftests/bpf/prog_tests/unpriv_bpf_disabled.c new file mode 100644 index 000000000000..1ed3cc2092db --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/unpriv_bpf_disabled.c @@ -0,0 +1,312 @@ +// 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_obj_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_obj_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_obj_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); +} |