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-rw-r--r--dhcpv4/dhcpv4.go10
-rw-r--r--dhcpv4/dhcpv4_test.go37
-rw-r--r--dhcpv4/fuzz.go41
-rw-r--r--dhcpv4/option_routes.go3
-rw-r--r--dhcpv4/option_routes_test.go14
-rw-r--r--dhcpv4/options.go10
-rw-r--r--dhcpv4/options_test.go18
7 files changed, 108 insertions, 25 deletions
diff --git a/dhcpv4/dhcpv4.go b/dhcpv4/dhcpv4.go
index ff72c9e..e85fc60 100644
--- a/dhcpv4/dhcpv4.go
+++ b/dhcpv4/dhcpv4.go
@@ -144,6 +144,7 @@ func New(modifiers ...Modifier) (*DHCPv4, error) {
d := DHCPv4{
OpCode: OpcodeBootRequest,
HWType: iana.HWTypeEthernet,
+ ClientHWAddr: make(net.HardwareAddr, 6),
HopCount: 0,
TransactionID: xid,
NumSeconds: 0,
@@ -476,9 +477,6 @@ func (d *DHCPv4) ToBytes() []byte {
// HwAddrLen
hlen := uint8(len(d.ClientHWAddr))
- if hlen == 0 && d.HWType == iana.HWTypeEthernet {
- hlen = 6
- }
buf.Write8(hlen)
buf.Write8(d.HopCount)
buf.WriteBytes(d.TransactionID[:])
@@ -492,13 +490,11 @@ func (d *DHCPv4) ToBytes() []byte {
copy(buf.WriteN(16), d.ClientHWAddr)
var sname [64]byte
- copy(sname[:], []byte(d.ServerHostName))
- sname[len(d.ServerHostName)] = 0
+ copy(sname[:63], []byte(d.ServerHostName))
buf.WriteBytes(sname[:])
var file [128]byte
- copy(file[:], []byte(d.BootFileName))
- file[len(d.BootFileName)] = 0
+ copy(file[:127], []byte(d.BootFileName))
buf.WriteBytes(file[:])
// The magic cookie.
diff --git a/dhcpv4/dhcpv4_test.go b/dhcpv4/dhcpv4_test.go
index ea3776c..6bbee31 100644
--- a/dhcpv4/dhcpv4_test.go
+++ b/dhcpv4/dhcpv4_test.go
@@ -3,6 +3,8 @@ package dhcpv4
import (
"bytes"
"net"
+ "strconv"
+ "strings"
"testing"
"github.com/insomniacslk/dhcp/iana"
@@ -80,16 +82,18 @@ func TestFromBytes(t *testing.T) {
// above
}
-func TestFromBytesZeroLength(t *testing.T) {
- data := []byte{}
- _, err := FromBytes(data)
- require.Error(t, err)
-}
-
-func TestFromBytesShortLength(t *testing.T) {
- data := []byte{1, 1, 6, 0}
- _, err := FromBytes(data)
- require.Error(t, err)
+func TestFromBytesGenericInvalid(t *testing.T) {
+ data := [][]byte{
+ {},
+ {1, 1, 6, 0},
+ }
+ t.Parallel()
+ for i, packet := range data {
+ t.Run(strconv.Itoa(i), func(t *testing.T) {
+ _, err := FromBytes(packet)
+ require.Error(t, err)
+ })
+ }
}
func TestFromBytesInvalidOptions(t *testing.T) {
@@ -178,6 +182,17 @@ func TestNewToBytes(t *testing.T) {
require.Equal(t, expected, got)
}
+func TestToBytesStringTooLong(t *testing.T) {
+ d, err := New()
+ if err != nil {
+ t.Fatal(err)
+ }
+ d.ServerHostName = strings.Repeat("a", 256)
+ d.BootFileName = strings.Repeat("a", 256)
+
+ require.NotPanics(t, func() { _ = d.ToBytes() })
+}
+
func TestGetOption(t *testing.T) {
d, err := New()
if err != nil {
@@ -339,7 +354,7 @@ func TestSummary(t *testing.T) {
" your IP: 0.0.0.0\n" +
" server IP: 0.0.0.0\n" +
" gateway IP: 0.0.0.0\n" +
- " client MAC: \n" +
+ " client MAC: 00:00:00:00:00:00\n" +
" server hostname: \n" +
" bootfile name: \n" +
" options:\n" +
diff --git a/dhcpv4/fuzz.go b/dhcpv4/fuzz.go
new file mode 100644
index 0000000..cf62ba5
--- /dev/null
+++ b/dhcpv4/fuzz.go
@@ -0,0 +1,41 @@
+// +build gofuzz
+
+package dhcpv4
+
+import (
+ "fmt"
+ "reflect"
+)
+
+// Fuzz is the entrypoint for go-fuzz
+func Fuzz(data []byte) int {
+ msg, err := FromBytes(data)
+ if err != nil {
+ return 0
+ }
+
+ serialized := msg.ToBytes()
+
+ // Compared to dhcpv6, dhcpv4 has padding and fixed-size fields containing
+ // variable-length data; We can't expect the library to output byte-for-byte
+ // identical packets after a round-trip.
+ // Instead, we check that after a round-trip, the packet reserializes to the
+ // same internal representation
+ rtMsg, err := FromBytes(serialized)
+
+ if err != nil || !reflect.DeepEqual(msg, rtMsg) {
+ fmt.Printf("Input: %x\n", data)
+ fmt.Printf("Round-trip: %x\n", serialized)
+ fmt.Println("Message: ", msg.Summary())
+ fmt.Printf("Go repr: %#v\n", msg)
+ fmt.Println("Reserialized: ", rtMsg.Summary())
+ fmt.Printf("Go repr: %#v\n", rtMsg)
+ if err != nil {
+ fmt.Printf("Got error while reserializing: %v\n", err)
+ panic("round-trip error: " + err.Error())
+ }
+ panic("round-trip different: " + msg.Summary())
+ }
+
+ return 1
+}
diff --git a/dhcpv4/option_routes.go b/dhcpv4/option_routes.go
index 603273a..c98d481 100644
--- a/dhcpv4/option_routes.go
+++ b/dhcpv4/option_routes.go
@@ -38,6 +38,9 @@ func (r Route) Marshal(buf *uio.Lexer) {
// Unmarshal implements uio.Unmarshaler.
func (r *Route) Unmarshal(buf *uio.Lexer) error {
maskSize := buf.Read8()
+ if maskSize > 32 {
+ return fmt.Errorf("invalid mask length %d in route option", maskSize)
+ }
r.Dest = &net.IPNet{
IP: make([]byte, net.IPv4len),
Mask: net.CIDRMask(int(maskSize), 32),
diff --git a/dhcpv4/option_routes_test.go b/dhcpv4/option_routes_test.go
index 19e331b..33f0ce7 100644
--- a/dhcpv4/option_routes_test.go
+++ b/dhcpv4/option_routes_test.go
@@ -16,9 +16,9 @@ func mustParseIPNet(s string) *net.IPNet {
func TestParseRoutes(t *testing.T) {
for _, tt := range []struct {
- p []byte
- want Routes
- err error
+ p []byte
+ want Routes
+ wantErr bool
}{
{
p: []byte{32, 10, 2, 3, 4, 0, 0, 0, 0},
@@ -51,10 +51,14 @@ func TestParseRoutes(t *testing.T) {
},
},
},
+ {
+ p: []byte{64, 10, 2, 3, 4},
+ wantErr: true, // Mask length 64 > 32
+ },
} {
var r Routes
- if err := r.FromBytes(tt.p); err != tt.err {
- t.Errorf("FromBytes(%v) = %v, want %v", tt.p, err, tt.err)
+ if err := r.FromBytes(tt.p); (err != nil) != tt.wantErr {
+ t.Errorf("FromBytes(%v) Unexpected error state: %v", tt.p, err)
}
if !reflect.DeepEqual(r, tt.want) {
diff --git a/dhcpv4/options.go b/dhcpv4/options.go
index ea902f6..058c4ad 100644
--- a/dhcpv4/options.go
+++ b/dhcpv4/options.go
@@ -185,12 +185,20 @@ func (o Options) Marshal(b *uio.Lexer) {
code := uint8(c)
// Even if the End option is in there, don't marshal it until
// the end.
- if code == optEnd {
+ // Don't write padding either, since the options are sorted
+ // it would always be written first which isn't useful
+ if code == optEnd || code == optPad {
continue
}
data := o[code]
+ // Ensure even 0-length options are written out
+ if len(data) == 0 {
+ b.Write8(code)
+ b.Write8(0)
+ continue
+ }
// RFC 3396: If more than 256 bytes of data are given, the
// option is simply listed multiple times.
for len(data) > 0 {
diff --git a/dhcpv4/options_test.go b/dhcpv4/options_test.go
index 6c5393c..3850d2d 100644
--- a/dhcpv4/options_test.go
+++ b/dhcpv4/options_test.go
@@ -194,9 +194,25 @@ func TestOptionsMarshal(t *testing.T) {
5, 1, 10,
),
},
+ {
+ // Test 0-length options
+ opts: Options{
+ 80: []byte{},
+ },
+ want: []byte{80, 0},
+ },
+ {
+ // Test special options, handled by the message marshalling code
+ // and ignored by the options marshalling code
+ opts: Options{
+ 0: []byte{}, // Padding
+ 255: []byte{}, // End of options
+ },
+ want: nil, // not written out
+ },
} {
t.Run(fmt.Sprintf("Test %02d", i), func(t *testing.T) {
- require.Equal(t, uio.ToBigEndian(tt.opts), tt.want)
+ require.Equal(t, tt.want, uio.ToBigEndian(tt.opts))
})
}
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 11:28:19 +0000