Merge pull request #25 from whyrusleeping/cleanup-new-bytes

cleanup panics and make NewFromBytes faster

.travis.yml

@@ -1,9 +1,8 @@
 language: go
 
 go:
-  - 1.3
-  - release
   - tip
+  - 1.6.1
 
 script:
   - go test -race -cpu=5 -v ./...

codec.go

@@ -1,9 +1,9 @@
 package multiaddr
 
 import (
+	"bytes"
 	"encoding/base32"
 	"encoding/binary"
-	"errors"
 	"fmt"
 	"net"
 	"strconv"
@@ -17,7 +17,7 @@ func stringToBytes(s string) ([]byte, error) {
 	// consume trailing slashes
 	s = strings.TrimRight(s, "/")
 
-	b := []byte{}
+	b := new(bytes.Buffer)
 	sp := strings.Split(s, "/")
 
 	if sp[0] != "" {
@@ -32,7 +32,7 @@ func stringToBytes(s string) ([]byte, error) {
 		if p.Code == 0 {
 			return nil, fmt.Errorf("no protocol with name %s", sp[0])
 		}
-		b = append(b, CodeToVarint(p.Code)...)
+		b.Write(CodeToVarint(p.Code))
 		sp = sp[1:]
 
 		if p.Size == 0 { // no length.
@@ -42,37 +42,59 @@ func stringToBytes(s string) ([]byte, error) {
 		if len(sp) < 1 {
 			return nil, fmt.Errorf("protocol requires address, none given: %s", p.Name)
 		}
+
 		a, err := addressStringToBytes(p, sp[0])
 		if err != nil {
 			return nil, fmt.Errorf("failed to parse %s: %s %s", p.Name, sp[0], err)
 		}
-		b = append(b, a...)
+		b.Write(a)
 		sp = sp[1:]
 	}
-	return b, nil
+
+	return b.Bytes(), nil
+}
+
+func validateBytes(b []byte) (err error) {
+	for len(b) > 0 {
+		code, n, err := ReadVarintCode(b)
+		if err != nil {
+			return err
+		}
+
+		b = b[n:]
+		p := ProtocolWithCode(code)
+		if p.Code == 0 {
+			return fmt.Errorf("no protocol with code %d", code)
+		}
+
+		if p.Size == 0 {
+			continue
+		}
+
+		size, err := sizeForAddr(p, b)
+		if err != nil {
+			return err
+		}
+
+		if len(b) < size || size < 0 {
+			return fmt.Errorf("invalid value for size")
+		}
+
+		b = b[size:]
+	}
+
+	return nil
 }
 
 func bytesToString(b []byte) (ret string, err error) {
-	// panic handler, in case we try accessing bytes incorrectly.
-	defer func() {
-		if e := recover(); e != nil {
-			ret = ""
-			switch e := e.(type) {
-			case error:
-				err = e
-			case string:
-				err = errors.New(e)
-			default:
-				err = fmt.Errorf("%v", e)
-			}
-		}
-	}()
-
 	s := ""
 
 	for len(b) > 0 {
+		code, n, err := ReadVarintCode(b)
+		if err != nil {
+			return "", err
+		}
 
-		code, n := ReadVarintCode(b)
 		b = b[n:]
 		p := ProtocolWithCode(code)
 		if p.Code == 0 {
@@ -84,7 +106,15 @@ func bytesToString(b []byte) (ret string, err error) {
 			continue
 		}
 
-		size := sizeForAddr(p, b)
+		size, err := sizeForAddr(p, b)
+		if err != nil {
+			return "", err
+		}
+
+		if len(b) < size || size < 0 {
+			return "", fmt.Errorf("invalid value for size")
+		}
+
 		a, err := addressBytesToString(p, b[:size])
 		if err != nil {
 			return "", err
@@ -98,36 +128,40 @@ func bytesToString(b []byte) (ret string, err error) {
 	return s, nil
 }
 
-func sizeForAddr(p Protocol, b []byte) int {
+func sizeForAddr(p Protocol, b []byte) (int, error) {
 	switch {
 	case p.Size > 0:
-		return (p.Size / 8)
+		return (p.Size / 8), nil
 	case p.Size == 0:
-		return 0
+		return 0, nil
 	default:
-		size, n := ReadVarintCode(b)
-		return size + n
+		size, n, err := ReadVarintCode(b)
+		if err != nil {
+			return 0, err
+		}
+
+		return size + n, nil
 	}
 }
 
-func bytesSplit(b []byte) (ret [][]byte, err error) {
-	// panic handler, in case we try accessing bytes incorrectly.
-	defer func() {
-		if e := recover(); e != nil {
-			ret = [][]byte{}
-			err = e.(error)
-		}
-	}()
-
-	ret = [][]byte{}
+func bytesSplit(b []byte) ([][]byte, error) {
+	var ret [][]byte
 	for len(b) > 0 {
-		code, n := ReadVarintCode(b)
+		code, n, err := ReadVarintCode(b)
+		if err != nil {
+			return nil, err
+		}
+
 		p := ProtocolWithCode(code)
 		if p.Code == 0 {
-			return [][]byte{}, fmt.Errorf("no protocol with code %d", b[0])
+			return nil, fmt.Errorf("no protocol with code %d", b[0])
+		}
+
+		size, err := sizeForAddr(p, b[n:])
+		if err != nil {
+			return nil, err
 		}
 
-		size := sizeForAddr(p, b[n:])
 		length := n + size
 		ret = append(ret, b[:length])
 		b = b[length:]
@@ -228,17 +262,21 @@ func addressBytesToString(p Protocol, b []byte) (string, error) {
 
 	case P_IPFS: // ipfs
 		// the address is a varint-prefixed multihash string representation
-		size, n := ReadVarintCode(b)
+		size, n, err := ReadVarintCode(b)
+		if err != nil {
+			return "", err
+		}
+
 		b = b[n:]
 		if len(b) != size {
-			panic("inconsistent lengths")
+			return "", fmt.Errorf("inconsistent lengths")
 		}
 		m, err := mh.Cast(b)
 		if err != nil {
 			return "", err
 		}
 		return m.B58String(), nil
+	default:
+		return "", fmt.Errorf("unknown protocol")
 	}
-
-	return "", fmt.Errorf("unknown protocol")
 }

multiaddr.go

@@ -3,6 +3,7 @@ package multiaddr
 import (
 	"bytes"
 	"fmt"
+	"log"
 	"strings"
 )
 
@@ -12,7 +13,13 @@ type multiaddr struct {
 }
 
 // NewMultiaddr parses and validates an input string, returning a *Multiaddr
-func NewMultiaddr(s string) (Multiaddr, error) {
+func NewMultiaddr(s string) (a Multiaddr, err error) {
+	defer func() {
+		if e := recover(); e != nil {
+			log.Printf("Panic in NewMultiaddr on input %q: %s", s, e)
+			err = fmt.Errorf("%v", e)
+		}
+	}()
 	b, err := stringToBytes(s)
 	if err != nil {
 		return nil, err
@@ -22,12 +29,19 @@ func NewMultiaddr(s string) (Multiaddr, error) {
 
 // NewMultiaddrBytes initializes a Multiaddr from a byte representation.
 // It validates it as an input string.
-func NewMultiaddrBytes(b []byte) (Multiaddr, error) {
-	s, err := bytesToString(b)
-	if err != nil {
+func NewMultiaddrBytes(b []byte) (a Multiaddr, err error) {
+	defer func() {
+		if e := recover(); e != nil {
+			log.Printf("Panic in NewMultiaddrBytes on input %q: %s", b, e)
+			err = fmt.Errorf("%v", e)
+		}
+	}()
+
+	if err := validateBytes(b); err != nil {
 		return nil, err
 	}
-	return NewMultiaddr(s)
+
+	return &multiaddr{bytes: b}, nil
 }
 
 // Equal tests whether two multiaddrs are equal
@@ -64,11 +78,14 @@ func (m *multiaddr) Protocols() []Protocol {
 		}
 	}()
 
-	size := 0
-	ps := []Protocol{}
-	b := m.bytes[:]
+	var ps []Protocol
+	b := m.bytes
 	for len(b) > 0 {
-		code, n := ReadVarintCode(b)
+		code, n, err := ReadVarintCode(b)
+		if err != nil {
+			panic(err)
+		}
+
 		p := ProtocolWithCode(code)
 		if p.Code == 0 {
 			// this is a panic (and not returning err) because this should've been
@@ -78,7 +95,11 @@ func (m *multiaddr) Protocols() []Protocol {
 		ps = append(ps, p)
 		b = b[n:]
 
-		size = sizeForAddr(p, b)
+		size, err := sizeForAddr(p, b)
+		if err != nil {
+			panic(err)
+		}
+
 		b = b[size:]
 	}
 	return ps

multiaddr_test.go

@@ -3,7 +3,10 @@ package multiaddr
 import (
 	"bytes"
 	"encoding/hex"
+	"math/rand"
+	"strings"
 	"testing"
+	"time"
 )
 
 func newMultiaddr(t *testing.T, a string) Multiaddr {
@@ -138,6 +141,10 @@ func TestStringToBytes(t *testing.T) {
 		if !bytes.Equal(b1, b2) {
 			t.Error("failed to convert", s, "to", b1, "got", b2)
 		}
+
+		if err := validateBytes(b2); err != nil {
+			t.Error(err)
+		}
 	}
 
 	testString("/ip4/127.0.0.1/udp/1234", "047f0000011104d2")
@@ -153,6 +160,10 @@ func TestBytesToString(t *testing.T) {
 			t.Error("failed to decode hex", h)
 		}
 
+		if err := validateBytes(b); err != nil {
+			t.Error(err)
+		}
+
 		s2, err := bytesToString(b)
 		if err != nil {
 			t.Error("failed to convert", b)
@@ -246,7 +257,7 @@ func TestProtocolsWithString(t *testing.T) {
 	for s, ps1 := range good {
 		ps2, err := ProtocolsWithString(s)
 		if err != nil {
-			t.Error("ProtocolsWithString(%s) should have succeeded", s)
+			t.Errorf("ProtocolsWithString(%s) should have succeeded", s)
 		}
 
 		for i, ps1p := range ps1 {
@@ -266,7 +277,7 @@ func TestProtocolsWithString(t *testing.T) {
 
 	for _, s := range bad {
 		if _, err := ProtocolsWithString(s); err == nil {
-			t.Error("ProtocolsWithString(%s) should have failed", s)
+			t.Errorf("ProtocolsWithString(%s) should have failed", s)
 		}
 	}
 
@@ -309,7 +320,7 @@ func assertValueForProto(t *testing.T, a Multiaddr, p int, exp string) {
 	}
 
 	if fv != exp {
-		t.Fatalf("expected %q for %d in %d, but got %q instead", exp, p, a, fv)
+		t.Fatalf("expected %q for %d in %s, but got %q instead", exp, p, a, fv)
 	}
 }
 
@@ -342,3 +353,55 @@ func TestGetValue(t *testing.T) {
 	assertValueForProto(t, a, P_UDP, "12345")
 	assertValueForProto(t, a, P_UTP, "")
 }
+
+func TestFuzzBytes(t *testing.T) {
+	rand.Seed(time.Now().UnixNano())
+	// Bump up these numbers if you want to stress this
+	buf := make([]byte, 256)
+	for i := 0; i < 2000; i++ {
+		l := rand.Intn(len(buf))
+		rand.Read(buf[:l])
+
+		// just checking that it doesnt panic
+		ma, err := NewMultiaddrBytes(buf[:l])
+		if err == nil {
+			// for any valid multiaddrs, make sure these calls don't panic
+			_ = ma.String()
+			ma.Protocols()
+		}
+	}
+}
+
+func randMaddrString() string {
+	good_corpus := []string{"tcp", "ip", "udp", "ipfs", "0.0.0.0", "127.0.0.1", "12345", "QmbHVEEepCi7rn7VL7Exxpd2Ci9NNB6ifvqwhsrbRMgQFP"}
+
+	size := rand.Intn(256)
+	parts := make([]string, 0, size)
+	for i := 0; i < size; i++ {
+		switch rand.Intn(5) {
+		case 0, 1, 2:
+			parts = append(parts, good_corpus[rand.Intn(len(good_corpus))])
+		default:
+			badbuf := make([]byte, rand.Intn(256))
+			rand.Read(badbuf)
+			parts = append(parts, string(badbuf))
+		}
+	}
+
+	return "/" + strings.Join(parts, "/")
+}
+
+func TestFuzzString(t *testing.T) {
+	rand.Seed(time.Now().UnixNano())
+	// Bump up these numbers if you want to stress this
+	for i := 0; i < 2000; i++ {
+
+		// just checking that it doesnt panic
+		ma, err := NewMultiaddr(randMaddrString())
+		if err == nil {
+			// for any valid multiaddrs, make sure these calls don't panic
+			_ = ma.String()
+			ma.Protocols()
+		}
+	}
+}

protocols.go

@@ -117,16 +117,19 @@ func CodeToVarint(num int) []byte {
 
 // VarintToCode converts a varint-encoded []byte to an integer protocol code
 func VarintToCode(buf []byte) int {
-	num, _ := ReadVarintCode(buf)
+	num, _, err := ReadVarintCode(buf)
+	if err != nil {
+		panic(err)
+	}
 	return num
 }
 
 // ReadVarintCode reads a varint code from the beginning of buf.
 // returns the code, and the number of bytes read.
-func ReadVarintCode(buf []byte) (int, int) {
+func ReadVarintCode(buf []byte) (int, int, error) {
 	num, n := binary.Uvarint(buf)
 	if n < 0 {
-		panic("varints larger than uint64 not yet supported")
+		return 0, 0, fmt.Errorf("varints larger than uint64 not yet supported")
 	}
-	return int(num), n
+	return int(num), n, nil
 }