From e8c13c4d9b36065903a025f163db87a7afff7307 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 22 Aug 2019 22:52:14 -0700 Subject: [PATCH] selftests/bpf: verifier precise tests Use BPF_F_TEST_STATE_FREQ flag to check that precision tracking works as expected by comparing every step it takes. Signed-off-by: Alexei Starovoitov Acked-by: Song Liu Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/test_verifier.c | 68 ++++++++-- .../testing/selftests/bpf/verifier/precise.c | 117 ++++++++++++++++++ 2 files changed, 174 insertions(+), 11 deletions(-) create mode 100644 tools/testing/selftests/bpf/verifier/precise.c diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 44e2d640b088..d27fd929abb9 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -61,6 +61,7 @@ #define UNPRIV_SYSCTL "kernel/unprivileged_bpf_disabled" static bool unpriv_disabled = false; static int skips; +static bool verbose = false; struct bpf_test { const char *descr; @@ -92,7 +93,8 @@ struct bpf_test { enum { UNDEF, ACCEPT, - REJECT + REJECT, + VERBOSE_ACCEPT, } result, result_unpriv; enum bpf_prog_type prog_type; uint8_t flags; @@ -859,6 +861,36 @@ static int do_prog_test_run(int fd_prog, bool unpriv, uint32_t expected_val, return 0; } +static bool cmp_str_seq(const char *log, const char *exp) +{ + char needle[80]; + const char *p, *q; + int len; + + do { + p = strchr(exp, '\t'); + if (!p) + p = exp + strlen(exp); + + len = p - exp; + if (len >= sizeof(needle) || !len) { + printf("FAIL\nTestcase bug\n"); + return false; + } + strncpy(needle, exp, len); + needle[len] = 0; + q = strstr(log, needle); + if (!q) { + printf("FAIL\nUnexpected verifier log in successful load!\n" + "EXP: %s\nRES:\n", needle); + return false; + } + log = q + len; + exp = p + 1; + } while (*p); + return true; +} + static void do_test_single(struct bpf_test *test, bool unpriv, int *passes, int *errors) { @@ -897,14 +929,20 @@ static void do_test_single(struct bpf_test *test, bool unpriv, pflags |= BPF_F_STRICT_ALIGNMENT; if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS) pflags |= BPF_F_ANY_ALIGNMENT; + if (test->flags & ~3) + pflags |= test->flags; + expected_ret = unpriv && test->result_unpriv != UNDEF ? + test->result_unpriv : test->result; + expected_err = unpriv && test->errstr_unpriv ? + test->errstr_unpriv : test->errstr; memset(&attr, 0, sizeof(attr)); attr.prog_type = prog_type; attr.expected_attach_type = test->expected_attach_type; attr.insns = prog; attr.insns_cnt = prog_len; attr.license = "GPL"; - attr.log_level = 4; + attr.log_level = verbose || expected_ret == VERBOSE_ACCEPT ? 1 : 4; attr.prog_flags = pflags; fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog)); @@ -914,14 +952,9 @@ static void do_test_single(struct bpf_test *test, bool unpriv, goto close_fds; } - expected_ret = unpriv && test->result_unpriv != UNDEF ? - test->result_unpriv : test->result; - expected_err = unpriv && test->errstr_unpriv ? - test->errstr_unpriv : test->errstr; - alignment_prevented_execution = 0; - if (expected_ret == ACCEPT) { + if (expected_ret == ACCEPT || expected_ret == VERBOSE_ACCEPT) { if (fd_prog < 0) { printf("FAIL\nFailed to load prog '%s'!\n", strerror(errno)); @@ -932,6 +965,9 @@ static void do_test_single(struct bpf_test *test, bool unpriv, (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS)) alignment_prevented_execution = 1; #endif + if (expected_ret == VERBOSE_ACCEPT && !cmp_str_seq(bpf_vlog, expected_err)) { + goto fail_log; + } } else { if (fd_prog >= 0) { printf("FAIL\nUnexpected success to load!\n"); @@ -957,6 +993,9 @@ static void do_test_single(struct bpf_test *test, bool unpriv, } } + if (verbose) + printf(", verifier log:\n%s", bpf_vlog); + run_errs = 0; run_successes = 0; if (!alignment_prevented_execution && fd_prog >= 0) { @@ -1097,17 +1136,24 @@ int main(int argc, char **argv) { unsigned int from = 0, to = ARRAY_SIZE(tests); bool unpriv = !is_admin(); + int arg = 1; + + if (argc > 1 && strcmp(argv[1], "-v") == 0) { + arg++; + verbose = true; + argc--; + } if (argc == 3) { - unsigned int l = atoi(argv[argc - 2]); - unsigned int u = atoi(argv[argc - 1]); + unsigned int l = atoi(argv[arg]); + unsigned int u = atoi(argv[arg + 1]); if (l < to && u < to) { from = l; to = u + 1; } } else if (argc == 2) { - unsigned int t = atoi(argv[argc - 1]); + unsigned int t = atoi(argv[arg]); if (t < to) { from = t; diff --git a/tools/testing/selftests/bpf/verifier/precise.c b/tools/testing/selftests/bpf/verifier/precise.c new file mode 100644 index 000000000000..a20953c23721 --- /dev/null +++ b/tools/testing/selftests/bpf/verifier/precise.c @@ -0,0 +1,117 @@ +{ + "precise: test 1", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_LD_MAP_FD(BPF_REG_6, 0), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + + BPF_MOV64_REG(BPF_REG_9, BPF_REG_0), + + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + + BPF_MOV64_REG(BPF_REG_8, BPF_REG_0), + + BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), /* map_value_ptr -= map_value_ptr */ + BPF_MOV64_REG(BPF_REG_2, BPF_REG_9), + BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 8, 1), + BPF_EXIT_INSN(), + + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1), /* R2=inv(umin=1, umax=8) */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + .fixup_map_array_48b = { 1 }, + .result = VERBOSE_ACCEPT, + .errstr = + "26: (85) call bpf_probe_read#4\ + last_idx 26 first_idx 20\ + regs=4 stack=0 before 25\ + regs=4 stack=0 before 24\ + regs=4 stack=0 before 23\ + regs=4 stack=0 before 22\ + regs=4 stack=0 before 20\ + parent didn't have regs=4 stack=0 marks\ + last_idx 19 first_idx 10\ + regs=4 stack=0 before 19\ + regs=200 stack=0 before 18\ + regs=300 stack=0 before 17\ + regs=201 stack=0 before 15\ + regs=201 stack=0 before 14\ + regs=200 stack=0 before 13\ + regs=200 stack=0 before 12\ + regs=200 stack=0 before 11\ + regs=200 stack=0 before 10\ + parent already had regs=0 stack=0 marks", +}, +{ + "precise: test 2", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_LD_MAP_FD(BPF_REG_6, 0), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + + BPF_MOV64_REG(BPF_REG_9, BPF_REG_0), + + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + + BPF_MOV64_REG(BPF_REG_8, BPF_REG_0), + + BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), /* map_value_ptr -= map_value_ptr */ + BPF_MOV64_REG(BPF_REG_2, BPF_REG_9), + BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 8, 1), + BPF_EXIT_INSN(), + + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1), /* R2=inv(umin=1, umax=8) */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + .fixup_map_array_48b = { 1 }, + .result = VERBOSE_ACCEPT, + .flags = BPF_F_TEST_STATE_FREQ, + .errstr = + "26: (85) call bpf_probe_read#4\ + last_idx 26 first_idx 22\ + regs=4 stack=0 before 25\ + regs=4 stack=0 before 24\ + regs=4 stack=0 before 23\ + regs=4 stack=0 before 22\ + parent didn't have regs=4 stack=0 marks\ + last_idx 20 first_idx 20\ + regs=4 stack=0 before 20\ + parent didn't have regs=4 stack=0 marks\ + last_idx 19 first_idx 17\ + regs=4 stack=0 before 19\ + regs=200 stack=0 before 18\ + regs=300 stack=0 before 17\ + parent already had regs=0 stack=0 marks", +}, -- 2.45.2