From: Andrii Nakryiko Date: Thu, 6 Apr 2023 23:42:05 +0000 (-0700) Subject: selftests/bpf: Add verifier log tests for BPF_BTF_LOAD command X-Git-Tag: v6.6.7~2736^2~129^2~19^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=054b6c7866c7a2537fffd4aa12d88aac47db60f9;p=platform%2Fkernel%2Flinux-starfive.git selftests/bpf: Add verifier log tests for BPF_BTF_LOAD command Add verifier log tests for BPF_BTF_LOAD command, which are very similar, conceptually, to BPF_PROG_LOAD tests. These are two separate commands dealing with verbose verifier log, so should be both tested separately. Test that log_buf==NULL condition *does not* return -ENOSPC. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Lorenz Bauer Link: https://lore.kernel.org/bpf/20230406234205.323208-20-andrii@kernel.org --- diff --git a/tools/testing/selftests/bpf/prog_tests/verifier_log.c b/tools/testing/selftests/bpf/prog_tests/verifier_log.c index 9ae0ac6..475092a 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier_log.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier_log.c @@ -249,6 +249,190 @@ cleanup: test_log_buf__destroy(skel); } +static const void *btf_data; +static u32 btf_data_sz; + +static int load_btf(struct bpf_btf_load_opts *opts, bool expect_err) +{ + int fd; + + fd = bpf_btf_load(btf_data, btf_data_sz, opts); + if (fd >= 0) + close(fd); + if (expect_err) + ASSERT_LT(fd, 0, "btf_load_failure"); + else /* !expect_err */ + ASSERT_GT(fd, 0, "btf_load_success"); + return fd; +} + +static void verif_btf_log_subtest(bool bad_btf) +{ + LIBBPF_OPTS(bpf_btf_load_opts, opts); + struct btf *btf; + struct btf_type *t; + char *exp_log, op_name[32]; + size_t fixed_log_sz; + __u32 log_true_sz_fixed, log_true_sz_rolling; + int i, res; + + /* prepare simple BTF contents */ + btf = btf__new_empty(); + if (!ASSERT_OK_PTR(btf, "btf_new_empty")) + return; + res = btf__add_int(btf, "whatever", 4, 0); + if (!ASSERT_GT(res, 0, "btf_add_int_id")) + goto cleanup; + if (bad_btf) { + /* btf__add_int() doesn't allow bad value of size, so we'll just + * force-cast btf_type pointer and manually override size to invalid + * 3 if we need to simulate failure + */ + t = (void *)btf__type_by_id(btf, res); + if (!ASSERT_OK_PTR(t, "int_btf_type")) + goto cleanup; + t->size = 3; + } + + btf_data = btf__raw_data(btf, &btf_data_sz); + if (!ASSERT_OK_PTR(btf_data, "btf_data")) + goto cleanup; + + load_btf(&opts, bad_btf); + + opts.log_buf = logs.reference; + opts.log_size = sizeof(logs.reference); + opts.log_level = 1 | 8 /* BPF_LOG_FIXED */; + load_btf(&opts, bad_btf); + + fixed_log_sz = strlen(logs.reference) + 1; + if (!ASSERT_GT(fixed_log_sz, 50, "fixed_log_sz")) + goto cleanup; + memset(logs.reference + fixed_log_sz, 0, sizeof(logs.reference) - fixed_log_sz); + + /* validate BPF_LOG_FIXED truncation works as verifier log used to work */ + opts.log_buf = logs.buf; + opts.log_level = 1 | 8; /* fixed-length log */ + opts.log_size = 25; + res = load_btf(&opts, true); + ASSERT_EQ(res, -ENOSPC, "half_log_fd"); + ASSERT_EQ(strlen(logs.buf), 24, "log_fixed_25"); + ASSERT_STRNEQ(logs.buf, logs.reference, 24, op_name); + + /* validate rolling verifier log logic: try all variations of log buf + * length to force various truncation scenarios + */ + opts.log_buf = logs.buf; + opts.log_level = 1; /* rolling log */ + + /* prefill logs.buf with 'A's to detect any write beyond allowed length */ + memset(logs.filler, 'A', sizeof(logs.filler)); + logs.filler[sizeof(logs.filler) - 1] = '\0'; + memset(logs.buf, 'A', sizeof(logs.buf)); + logs.buf[sizeof(logs.buf) - 1] = '\0'; + + for (i = 1; i < fixed_log_sz; i++) { + opts.log_size = i; + + snprintf(op_name, sizeof(op_name), "log_roll_btf_load_%d", i); + res = load_btf(&opts, true); + if (!ASSERT_EQ(res, -ENOSPC, op_name)) + goto cleanup; + + exp_log = logs.reference + fixed_log_sz - i; + snprintf(op_name, sizeof(op_name), "log_roll_contents_%d", i); + if (!ASSERT_STREQ(logs.buf, exp_log, op_name)) { + printf("CMP:%d\nS1:'%s'\nS2:'%s'\n", + strcmp(logs.buf, exp_log), + logs.buf, exp_log); + goto cleanup; + } + + /* check that unused portions of logs.buf are not overwritten */ + snprintf(op_name, sizeof(op_name), "log_roll_unused_tail_%d", i); + if (!ASSERT_STREQ(logs.buf + i, logs.filler + i, op_name)) { + printf("CMP:%d\nS1:'%s'\nS2:'%s'\n", + strcmp(logs.buf + i, logs.filler + i), + logs.buf + i, logs.filler + i); + goto cleanup; + } + } + + /* (FIXED) get actual log size */ + opts.log_buf = logs.buf; + opts.log_level = 1 | 8; /* BPF_LOG_FIXED */ + opts.log_size = sizeof(logs.buf); + opts.log_true_size = 0; + res = load_btf(&opts, bad_btf); + ASSERT_NEQ(res, -ENOSPC, "btf_load_res_fixed"); + + log_true_sz_fixed = opts.log_true_size; + ASSERT_GT(log_true_sz_fixed, 0, "log_true_sz_fixed"); + + /* (FIXED, NULL) get actual log size */ + opts.log_buf = NULL; + opts.log_level = 1 | 8; /* BPF_LOG_FIXED */ + opts.log_size = 0; + opts.log_true_size = 0; + res = load_btf(&opts, bad_btf); + ASSERT_NEQ(res, -ENOSPC, "btf_load_res_fixed_null"); + ASSERT_EQ(opts.log_true_size, log_true_sz_fixed, "log_sz_fixed_null_eq"); + + /* (ROLLING) get actual log size */ + opts.log_buf = logs.buf; + opts.log_level = 1; + opts.log_size = sizeof(logs.buf); + opts.log_true_size = 0; + res = load_btf(&opts, bad_btf); + ASSERT_NEQ(res, -ENOSPC, "btf_load_res_rolling"); + + log_true_sz_rolling = opts.log_true_size; + ASSERT_EQ(log_true_sz_rolling, log_true_sz_fixed, "log_true_sz_eq"); + + /* (ROLLING, NULL) get actual log size */ + opts.log_buf = NULL; + opts.log_level = 1; + opts.log_size = 0; + opts.log_true_size = 0; + res = load_btf(&opts, bad_btf); + ASSERT_NEQ(res, -ENOSPC, "btf_load_res_rolling_null"); + ASSERT_EQ(opts.log_true_size, log_true_sz_rolling, "log_true_sz_null_eq"); + + /* (FIXED) expect -ENOSPC for one byte short log */ + opts.log_buf = logs.buf; + opts.log_level = 1 | 8; /* BPF_LOG_FIXED */ + opts.log_size = log_true_sz_fixed - 1; + opts.log_true_size = 0; + res = load_btf(&opts, true); + ASSERT_EQ(res, -ENOSPC, "btf_load_res_too_short_fixed"); + + /* (FIXED) expect *not* -ENOSPC with exact log_true_size buffer */ + opts.log_buf = logs.buf; + opts.log_level = 1 | 8; /* BPF_LOG_FIXED */ + opts.log_size = log_true_sz_fixed; + opts.log_true_size = 0; + res = load_btf(&opts, bad_btf); + ASSERT_NEQ(res, -ENOSPC, "btf_load_res_just_right_fixed"); + + /* (ROLLING) expect -ENOSPC for one byte short log */ + opts.log_buf = logs.buf; + opts.log_level = 1; + opts.log_size = log_true_sz_rolling - 1; + res = load_btf(&opts, true); + ASSERT_EQ(res, -ENOSPC, "btf_load_res_too_short_rolling"); + + /* (ROLLING) expect *not* -ENOSPC with exact log_true_size buffer */ + opts.log_buf = logs.buf; + opts.log_level = 1; + opts.log_size = log_true_sz_rolling; + opts.log_true_size = 0; + res = load_btf(&opts, bad_btf); + ASSERT_NEQ(res, -ENOSPC, "btf_load_res_just_right_rolling"); + +cleanup: + btf__free(btf); +} + void test_verifier_log(void) { if (test__start_subtest("good_prog-level1")) @@ -259,4 +443,8 @@ void test_verifier_log(void) verif_log_subtest("bad_prog", true, 1); if (test__start_subtest("bad_prog-level2")) verif_log_subtest("bad_prog", true, 2); + if (test__start_subtest("bad_btf")) + verif_btf_log_subtest(true /* bad btf */); + if (test__start_subtest("good_btf")) + verif_btf_log_subtest(false /* !bad btf */); }