blob: e945f41241529f829717d4e53fcb4664fe0bb74a [file] [log] [blame]
// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package zstd
import (
"bytes"
"io"
"os"
"os/exec"
"testing"
)
// badStrings is some inputs that FuzzReader failed on earlier.
var badStrings = []string{
"(\xb5/\xfdd00,\x05\x00\xc4\x0400000000000000000000000000000000000000000000000000000000000000000000000000000 \xa07100000000000000000000000000000000000000000000000000000000000000000000000000aM\x8a2y0B\b",
"(\xb5/\xfd00$\x05\x0020 00X70000a70000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
"(\xb5/\xfd00$\x05\x0020 00B00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
"(\xb5/\xfd00}\x00\x0020\x00\x9000000000000",
"(\xb5/\xfd00}\x00\x00&0\x02\x830!000000000",
"(\xb5/\xfd\x1002000$\x05\x0010\xcc0\xa8100000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
"(\xb5/\xfd\x1002000$\x05\x0000\xcc0\xa8100d\x0000001000000000000000000000000000000000000000000000000000000000000000000000000\x000000000000000000000000000000000000000000000000000000000000000000000000000000",
"(\xb5/\xfd001\x00\x0000000000000000000",
"(\xb5/\xfd00\xec\x00\x00&@\x05\x05A7002\x02\x00\x02\x00\x02\x0000000000000000",
"(\xb5/\xfd00\xec\x00\x00V@\x05\x0517002\x02\x00\x02\x00\x02\x0000000000000000",
"\x50\x2a\x4d\x18\x02\x00\x00\x00",
"(\xb5/\xfd\xe40000000\xfa20\x000",
}
// This is a simple fuzzer to see if the decompressor panics.
func FuzzReader(f *testing.F) {
for _, test := range tests {
f.Add([]byte(test.compressed))
}
for _, s := range badStrings {
f.Add([]byte(s))
}
f.Fuzz(func(t *testing.T, b []byte) {
r := NewReader(bytes.NewReader(b))
io.Copy(io.Discard, r)
})
}
// Fuzz test to verify that what we decompress is what we compress.
// This isn't a great fuzz test because the fuzzer can't efficiently
// explore the space of decompressor behavior, since it can't see
// what the compressor is doing. But it's better than nothing.
func FuzzDecompressor(f *testing.F) {
zstd := findZstd(f)
for _, test := range tests {
f.Add([]byte(test.uncompressed))
}
// Add some larger data, as that has more interesting compression.
f.Add(bytes.Repeat([]byte("abcdefghijklmnop"), 256))
var buf bytes.Buffer
for i := 0; i < 256; i++ {
buf.WriteByte(byte(i))
}
f.Add(bytes.Repeat(buf.Bytes(), 64))
f.Add(bigData(f))
f.Fuzz(func(t *testing.T, b []byte) {
cmd := exec.Command(zstd, "-z")
cmd.Stdin = bytes.NewReader(b)
var compressed bytes.Buffer
cmd.Stdout = &compressed
cmd.Stderr = os.Stderr
if err := cmd.Run(); err != nil {
t.Errorf("running zstd failed: %v", err)
}
r := NewReader(bytes.NewReader(compressed.Bytes()))
got, err := io.ReadAll(r)
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(got, b) {
showDiffs(t, got, b)
}
})
}
// Fuzz test to check that if we can decompress some data,
// so can zstd, and that we get the same result.
func FuzzReverse(f *testing.F) {
zstd := findZstd(f)
for _, test := range tests {
f.Add([]byte(test.compressed))
}
// Set a hook to reject some cases where we don't match zstd.
fuzzing = true
defer func() { fuzzing = false }()
f.Fuzz(func(t *testing.T, b []byte) {
r := NewReader(bytes.NewReader(b))
goExp, goErr := io.ReadAll(r)
cmd := exec.Command(zstd, "-d")
cmd.Stdin = bytes.NewReader(b)
var uncompressed bytes.Buffer
cmd.Stdout = &uncompressed
cmd.Stderr = os.Stderr
zstdErr := cmd.Run()
zstdExp := uncompressed.Bytes()
if goErr == nil && zstdErr == nil {
if !bytes.Equal(zstdExp, goExp) {
showDiffs(t, zstdExp, goExp)
}
} else {
// Ideally we should check that this package and
// the zstd program both fail or both succeed,
// and that if they both fail one byte sequence
// is an exact prefix of the other.
// Actually trying this proved to be frustrating,
// as the zstd program appears to accept invalid
// byte sequences using rules that are difficult
// to determine.
// So we just check the prefix.
c := len(goExp)
if c > len(zstdExp) {
c = len(zstdExp)
}
goExp = goExp[:c]
zstdExp = zstdExp[:c]
if !bytes.Equal(goExp, zstdExp) {
t.Error("byte mismatch after error")
t.Logf("Go error: %v\n", goErr)
t.Logf("zstd error: %v\n", zstdErr)
showDiffs(t, zstdExp, goExp)
}
}
})
}