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1// Copyright 2022 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5//go:build linux || (freebsd && amd64)
6
7package sanitizers_test
8
9import (
10	"internal/testenv"
11	"strings"
12	"testing"
13)
14
15func TestLibFuzzer(t *testing.T) {
16	// Skip tests in short mode.
17	if testing.Short() {
18		t.Skip("libfuzzer tests can take upwards of minutes to run; skipping in short mode")
19	}
20	testenv.MustHaveGoBuild(t)
21	testenv.MustHaveCGO(t)
22
23	goos, err := goEnv("GOOS")
24	if err != nil {
25		t.Fatal(err)
26	}
27	goarch, err := goEnv("GOARCH")
28	if err != nil {
29		t.Fatal(err)
30	}
31	if !libFuzzerSupported(goos, goarch) {
32		t.Skipf("skipping on %s/%s; libfuzzer option is not supported.", goos, goarch)
33	}
34	config := configure("fuzzer")
35	config.skipIfCSanitizerBroken(t)
36
37	cases := []struct {
38		goSrc         string
39		cSrc          string
40		expectedError string
41	}{
42		{goSrc: "libfuzzer1.go", expectedError: "panic: found it"},
43		{goSrc: "libfuzzer2.go", cSrc: "libfuzzer2.c", expectedError: "panic: found it"},
44	}
45	for _, tc := range cases {
46		tc := tc
47		name := strings.TrimSuffix(tc.goSrc, ".go")
48		t.Run(name, func(t *testing.T) {
49			t.Parallel()
50
51			dir := newTempDir(t)
52			defer dir.RemoveAll(t)
53
54			// build Go code in libfuzzer mode to a c-archive
55			outPath := dir.Join(name)
56			archivePath := dir.Join(name + ".a")
57			mustRun(t, config.goCmd("build", "-buildmode=c-archive", "-o", archivePath, srcPath(tc.goSrc)))
58
59			// build C code (if any) and link with Go code
60			cmd, err := cc(config.cFlags...)
61			if err != nil {
62				t.Fatalf("error running cc: %v", err)
63			}
64			cmd.Args = append(cmd.Args, config.ldFlags...)
65			cmd.Args = append(cmd.Args, "-o", outPath, "-I", dir.Base())
66			if tc.cSrc != "" {
67				cmd.Args = append(cmd.Args, srcPath(tc.cSrc))
68			}
69			cmd.Args = append(cmd.Args, archivePath)
70			mustRun(t, cmd)
71
72			cmd = hangProneCmd(outPath)
73			cmd.Dir = dir.Base()
74			outb, err := cmd.CombinedOutput()
75			out := string(outb)
76			if err == nil {
77				t.Fatalf("fuzzing succeeded unexpectedly; output:\n%s", out)
78			}
79			if !strings.Contains(out, tc.expectedError) {
80				t.Errorf("exited without expected error %q; got\n%s", tc.expectedError, out)
81			}
82		})
83	}
84}
85
86// libFuzzerSupported is a copy of the function internal/platform.FuzzInstrumented,
87// because the internal package can't be used here.
88func libFuzzerSupported(goos, goarch string) bool {
89	switch goarch {
90	case "amd64", "arm64":
91		// TODO(#14565): support more architectures.
92		switch goos {
93		case "darwin", "freebsd", "linux", "windows":
94			return true
95		default:
96			return false
97		}
98	default:
99		return false
100	}
101}
102