libfuzzer_test.go

     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  
     7  package sanitizers_test
     8  
     9  import (
    10  	"internal/testenv"
    11  	"strings"
    12  	"testing"
    13  )
    14  
    15  func 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.
    88  func 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
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