From 57e889269af3dd0609933e2550c4baee7a7eb84c Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 9 Dec 2021 11:38:38 -0800 Subject: selftests/bpf: Add test for libbpf's custom log_buf behavior Add a selftest that validates that per-program and per-object log_buf overrides work as expected. Also test same logic for low-level bpf_prog_load() and bpf_btf_load() APIs. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20211209193840.1248570-11-andrii@kernel.org --- tools/testing/selftests/bpf/prog_tests/log_buf.c | 276 +++++++++++++++++++++++ tools/testing/selftests/bpf/progs/test_log_buf.c | 24 ++ 2 files changed, 300 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/log_buf.c create mode 100644 tools/testing/selftests/bpf/progs/test_log_buf.c (limited to 'tools/testing') diff --git a/tools/testing/selftests/bpf/prog_tests/log_buf.c b/tools/testing/selftests/bpf/prog_tests/log_buf.c new file mode 100644 index 000000000000..e469b023962b --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/log_buf.c @@ -0,0 +1,276 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include +#include + +#include "test_log_buf.skel.h" + +static size_t libbpf_log_pos; +static char libbpf_log_buf[1024 * 1024]; +static bool libbpf_log_error; + +static int libbpf_print_cb(enum libbpf_print_level level, const char *fmt, va_list args) +{ + int emitted_cnt; + size_t left_cnt; + + left_cnt = sizeof(libbpf_log_buf) - libbpf_log_pos; + emitted_cnt = vsnprintf(libbpf_log_buf + libbpf_log_pos, left_cnt, fmt, args); + + if (emitted_cnt < 0 || emitted_cnt + 1 > left_cnt) { + libbpf_log_error = true; + return 0; + } + + libbpf_log_pos += emitted_cnt; + return 0; +} + +static void obj_load_log_buf(void) +{ + libbpf_print_fn_t old_print_cb = libbpf_set_print(libbpf_print_cb); + LIBBPF_OPTS(bpf_object_open_opts, opts); + const size_t log_buf_sz = 1024 * 1024; + struct test_log_buf* skel; + char *obj_log_buf, *good_log_buf, *bad_log_buf; + int err; + + obj_log_buf = malloc(3 * log_buf_sz); + if (!ASSERT_OK_PTR(obj_log_buf, "obj_log_buf")) + return; + + good_log_buf = obj_log_buf + log_buf_sz; + bad_log_buf = obj_log_buf + 2 * log_buf_sz; + obj_log_buf[0] = good_log_buf[0] = bad_log_buf[0] = '\0'; + + opts.kernel_log_buf = obj_log_buf; + opts.kernel_log_size = log_buf_sz; + opts.kernel_log_level = 4; /* for BTF this will turn into 1 */ + + /* In the first round every prog has its own log_buf, so libbpf logs + * don't have program failure logs + */ + skel = test_log_buf__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "skel_open")) + goto cleanup; + + /* set very verbose level for good_prog so we always get detailed logs */ + bpf_program__set_log_buf(skel->progs.good_prog, good_log_buf, log_buf_sz); + bpf_program__set_log_level(skel->progs.good_prog, 2); + + bpf_program__set_log_buf(skel->progs.bad_prog, bad_log_buf, log_buf_sz); + /* log_level 0 with custom log_buf means that verbose logs are not + * requested if program load is successful, but libbpf should retry + * with log_level 1 on error and put program's verbose load log into + * custom log_buf + */ + bpf_program__set_log_level(skel->progs.bad_prog, 0); + + err = test_log_buf__load(skel); + if (!ASSERT_ERR(err, "unexpected_load_success")) + goto cleanup; + + ASSERT_FALSE(libbpf_log_error, "libbpf_log_error"); + + /* there should be no prog loading log because we specified per-prog log buf */ + ASSERT_NULL(strstr(libbpf_log_buf, "-- BEGIN PROG LOAD LOG --"), "unexp_libbpf_log"); + ASSERT_OK_PTR(strstr(libbpf_log_buf, "prog 'bad_prog': BPF program load failed"), + "libbpf_log_not_empty"); + ASSERT_OK_PTR(strstr(obj_log_buf, "DATASEC license"), "obj_log_not_empty"); + ASSERT_OK_PTR(strstr(good_log_buf, "0: R1=ctx(id=0,off=0,imm=0) R10=fp0"), + "good_log_verbose"); + ASSERT_OK_PTR(strstr(bad_log_buf, "invalid access to map value, value_size=16 off=16000 size=4"), + "bad_log_not_empty"); + + if (env.verbosity > VERBOSE_NONE) { + printf("LIBBPF LOG: \n=================\n%s=================\n", libbpf_log_buf); + printf("OBJ LOG: \n=================\n%s=================\n", obj_log_buf); + printf("GOOD_PROG LOG:\n=================\n%s=================\n", good_log_buf); + printf("BAD_PROG LOG:\n=================\n%s=================\n", bad_log_buf); + } + + /* reset everything */ + test_log_buf__destroy(skel); + obj_log_buf[0] = good_log_buf[0] = bad_log_buf[0] = '\0'; + libbpf_log_buf[0] = '\0'; + libbpf_log_pos = 0; + libbpf_log_error = false; + + /* In the second round we let bad_prog's failure be logged through print callback */ + opts.kernel_log_buf = NULL; /* let everything through into print callback */ + opts.kernel_log_size = 0; + opts.kernel_log_level = 1; + + skel = test_log_buf__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "skel_open")) + goto cleanup; + + /* set normal verbose level for good_prog to check log_level is taken into account */ + bpf_program__set_log_buf(skel->progs.good_prog, good_log_buf, log_buf_sz); + bpf_program__set_log_level(skel->progs.good_prog, 1); + + err = test_log_buf__load(skel); + if (!ASSERT_ERR(err, "unexpected_load_success")) + goto cleanup; + + ASSERT_FALSE(libbpf_log_error, "libbpf_log_error"); + + /* this time prog loading error should be logged through print callback */ + ASSERT_OK_PTR(strstr(libbpf_log_buf, "libbpf: prog 'bad_prog': -- BEGIN PROG LOAD LOG --"), + "libbpf_log_correct"); + ASSERT_STREQ(obj_log_buf, "", "obj_log__empty"); + ASSERT_STREQ(good_log_buf, "processed 4 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0\n", + "good_log_ok"); + ASSERT_STREQ(bad_log_buf, "", "bad_log_empty"); + + if (env.verbosity > VERBOSE_NONE) { + printf("LIBBPF LOG: \n=================\n%s=================\n", libbpf_log_buf); + printf("OBJ LOG: \n=================\n%s=================\n", obj_log_buf); + printf("GOOD_PROG LOG:\n=================\n%s=================\n", good_log_buf); + printf("BAD_PROG LOG:\n=================\n%s=================\n", bad_log_buf); + } + +cleanup: + free(obj_log_buf); + test_log_buf__destroy(skel); + libbpf_set_print(old_print_cb); +} + +static void bpf_prog_load_log_buf(void) +{ + const struct bpf_insn good_prog_insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + const size_t good_prog_insn_cnt = sizeof(good_prog_insns) / sizeof(struct bpf_insn); + const struct bpf_insn bad_prog_insns[] = { + BPF_EXIT_INSN(), + }; + size_t bad_prog_insn_cnt = sizeof(bad_prog_insns) / sizeof(struct bpf_insn); + LIBBPF_OPTS(bpf_prog_load_opts, opts); + const size_t log_buf_sz = 1024 * 1024; + char *log_buf; + int fd = -1; + + log_buf = malloc(log_buf_sz); + if (!ASSERT_OK_PTR(log_buf, "log_buf_alloc")) + return; + opts.log_buf = log_buf; + opts.log_size = log_buf_sz; + + /* with log_level == 0 log_buf shoud stay empty for good prog */ + log_buf[0] = '\0'; + opts.log_level = 0; + fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "good_prog", "GPL", + good_prog_insns, good_prog_insn_cnt, &opts); + ASSERT_STREQ(log_buf, "", "good_log_0"); + ASSERT_GE(fd, 0, "good_fd1"); + if (fd >= 0) + close(fd); + fd = -1; + + /* log_level == 2 should always fill log_buf, even for good prog */ + log_buf[0] = '\0'; + opts.log_level = 2; + fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "good_prog", "GPL", + good_prog_insns, good_prog_insn_cnt, &opts); + ASSERT_OK_PTR(strstr(log_buf, "0: R1=ctx(id=0,off=0,imm=0) R10=fp0"), "good_log_2"); + ASSERT_GE(fd, 0, "good_fd2"); + if (fd >= 0) + close(fd); + fd = -1; + + /* log_level == 0 should fill log_buf for bad prog */ + log_buf[0] = '\0'; + opts.log_level = 0; + fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "bad_prog", "GPL", + bad_prog_insns, bad_prog_insn_cnt, &opts); + ASSERT_OK_PTR(strstr(log_buf, "R0 !read_ok"), "bad_log_0"); + ASSERT_LT(fd, 0, "bad_fd"); + if (fd >= 0) + close(fd); + fd = -1; + + free(log_buf); +} + +static void bpf_btf_load_log_buf(void) +{ + LIBBPF_OPTS(bpf_btf_load_opts, opts); + const size_t log_buf_sz = 1024 * 1024; + const void *raw_btf_data; + __u32 raw_btf_size; + struct btf *btf; + char *log_buf; + int fd = -1; + + btf = btf__new_empty(); + if (!ASSERT_OK_PTR(btf, "empty_btf")) + return; + + ASSERT_GT(btf__add_int(btf, "int", 4, 0), 0, "int_type"); + + raw_btf_data = btf__raw_data(btf, &raw_btf_size); + if (!ASSERT_OK_PTR(raw_btf_data, "raw_btf_data_good")) + goto cleanup; + + log_buf = malloc(log_buf_sz); + if (!ASSERT_OK_PTR(log_buf, "log_buf_alloc")) + goto cleanup; + opts.log_buf = log_buf; + opts.log_size = log_buf_sz; + + /* with log_level == 0 log_buf shoud stay empty for good BTF */ + log_buf[0] = '\0'; + opts.log_level = 0; + fd = bpf_btf_load(raw_btf_data, raw_btf_size, &opts); + ASSERT_STREQ(log_buf, "", "good_log_0"); + ASSERT_GE(fd, 0, "good_fd1"); + if (fd >= 0) + close(fd); + fd = -1; + + /* log_level == 2 should always fill log_buf, even for good BTF */ + log_buf[0] = '\0'; + opts.log_level = 2; + fd = bpf_btf_load(raw_btf_data, raw_btf_size, &opts); + printf("LOG_BUF: %s\n", log_buf); + ASSERT_OK_PTR(strstr(log_buf, "magic: 0xeb9f"), "good_log_2"); + ASSERT_GE(fd, 0, "good_fd2"); + if (fd >= 0) + close(fd); + fd = -1; + + /* make BTF bad, add pointer pointing to non-existing type */ + ASSERT_GT(btf__add_ptr(btf, 100), 0, "bad_ptr_type"); + + raw_btf_data = btf__raw_data(btf, &raw_btf_size); + if (!ASSERT_OK_PTR(raw_btf_data, "raw_btf_data_bad")) + goto cleanup; + + /* log_level == 0 should fill log_buf for bad BTF */ + log_buf[0] = '\0'; + opts.log_level = 0; + fd = bpf_btf_load(raw_btf_data, raw_btf_size, &opts); + printf("LOG_BUF: %s\n", log_buf); + ASSERT_OK_PTR(strstr(log_buf, "[2] PTR (anon) type_id=100 Invalid type_id"), "bad_log_0"); + ASSERT_LT(fd, 0, "bad_fd"); + if (fd >= 0) + close(fd); + fd = -1; + +cleanup: + free(log_buf); + btf__free(btf); +} + +void test_log_buf(void) +{ + if (test__start_subtest("obj_load_log_buf")) + obj_load_log_buf(); + if (test__start_subtest("bpf_prog_load_log_buf")) + bpf_prog_load_log_buf(); + if (test__start_subtest("bpf_btf_load_log_buf")) + bpf_btf_load_log_buf(); +} diff --git a/tools/testing/selftests/bpf/progs/test_log_buf.c b/tools/testing/selftests/bpf/progs/test_log_buf.c new file mode 100644 index 000000000000..199f459bd5ae --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_log_buf.c @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include +#include + +int a[4]; +const volatile int off = 4000; + +SEC("raw_tp/sys_enter") +int good_prog(const void *ctx) +{ + a[0] = (int)(long)ctx; + return a[1]; +} + +SEC("raw_tp/sys_enter") +int bad_prog(const void *ctx) +{ + /* out of bounds access */ + return a[off]; +} + +char _license[] SEC("license") = "GPL"; -- cgit v1.2.3