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 <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 44e2d640b088ca10668d28e3a1c3b6acae8ec194..d27fd929abb9003ec4562e970ee321c17e730532 100644 (file)
--- 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 (file)
index 0000000..a20953c
--- /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",
+},