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  		name := strings.TrimSuffix(tc.goSrc, ".go")
    47  		t.Run(name, func(t *testing.T) {
    48  			t.Parallel()
    49  
    50  			dir := newTempDir(t)
    51  			defer dir.RemoveAll(t)
    52  
    53  			// build Go code in libfuzzer mode to a c-archive
    54  			outPath := dir.Join(name)
    55  			archivePath := dir.Join(name + ".a")
    56  			mustRun(t, config.goCmd("build", "-buildmode=c-archive", "-o", archivePath, srcPath(tc.goSrc)))
    57  
    58  			// build C code (if any) and link with Go code
    59  			cmd, err := cc(config.cFlags...)
    60  			if err != nil {
    61  				t.Fatalf("error running cc: %v", err)
    62  			}
    63  			cmd.Args = append(cmd.Args, config.ldFlags...)
    64  			cmd.Args = append(cmd.Args, "-o", outPath, "-I", dir.Base())
    65  			if tc.cSrc != "" {
    66  				cmd.Args = append(cmd.Args, srcPath(tc.cSrc))
    67  			}
    68  			cmd.Args = append(cmd.Args, archivePath)
    69  			mustRun(t, cmd)
    70  
    71  			cmd = hangProneCmd(outPath)
    72  			cmd.Dir = dir.Base()
    73  			outb, err := cmd.CombinedOutput()
    74  			out := string(outb)
    75  			if err == nil {
    76  				t.Fatalf("fuzzing succeeded unexpectedly; output:\n%s", out)
    77  			}
    78  			if !strings.Contains(out, tc.expectedError) {
    79  				t.Errorf("exited without expected error %q; got\n%s", tc.expectedError, out)
    80  			}
    81  		})
    82  	}
    83  }
    84  
    85  // libFuzzerSupported is a copy of the function internal/platform.FuzzInstrumented,
    86  // because the internal package can't be used here.
    87  func libFuzzerSupported(goos, goarch string) bool {
    88  	switch goarch {
    89  	case "amd64", "arm64":
    90  		// TODO(#14565): support more architectures.
    91  		switch goos {
    92  		case "darwin", "freebsd", "linux", "windows":
    93  			return true
    94  		default:
    95  			return false
    96  		}
    97  	case "loong64":
    98  		return true
    99  	default:
   100  		return false
   101  	}
   102  }
   103
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