fixed possible crashes on parsing of bgp messages

9 files changed, 79 insertions, 3 deletions

diff --git a/pkg/packet/bgp/bgp.go b/pkg/packet/bgp/bgp.go
index 2f117830..150c6c24 100644
--- a/pkg/packet/bgp/bgp.go
+++ b/pkg/packet/bgp/bgp.go
@@ -977,6 +977,9 @@ func (o *OptionParameterCapability) DecodeFromBytes(data []byte) error {
 			return err
 		}
 		o.Capability = append(o.Capability, c)
+		if c.Len() == 0 || len(data) < c.Len() {
+			return NewMessageError(BGP_ERROR_MESSAGE_HEADER_ERROR, BGP_ERROR_SUB_BAD_MESSAGE_LENGTH, nil, "Bad capability length")
+		}
 		data = data[c.Len():]
 	}
 	return nil
@@ -1051,7 +1054,7 @@ func (msg *BGPOpen) DecodeFromBytes(data []byte, options ...*MarshallingOption)
 		}
 		paramtype := data[0]
 		paramlen := data[1]
-		if rest < paramlen+2 {
+		if paramlen >= 254 || rest < paramlen+2 {
 			return NewMessageError(BGP_ERROR_MESSAGE_HEADER_ERROR, BGP_ERROR_SUB_BAD_MESSAGE_LENGTH, nil, "Malformed BGP Open message")
 		}
 		rest -= paramlen + 2
@@ -12170,6 +12173,9 @@ func (p *PathAttributeAigp) DecodeFromBytes(data []byte, options ...*Marshalling
 	for len(value) > 3 {
 		typ := value[0]
 		length := binary.BigEndian.Uint16(value[1:3])
+		if length <= 3 {
+			return NewMessageError(BGP_ERROR_MESSAGE_HEADER_ERROR, BGP_ERROR_SUB_BAD_MESSAGE_LENGTH, nil, "Malformed BGP message")
+		}
 		if len(value) < int(length) {
 			break
 		}
diff --git a/pkg/packet/bgp/bgp_test.go b/pkg/packet/bgp/bgp_test.go
index d821d072..112a9b4f 100644
--- a/pkg/packet/bgp/bgp_test.go
+++ b/pkg/packet/bgp/bgp_test.go
@@ -18,9 +18,13 @@ package bgp
 import (
 	"bytes"
 	"encoding/binary"
+	"io/ioutil"
 	"net"
+	"os"
+	"path/filepath"
 	"reflect"
 	"strconv"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -1194,6 +1198,69 @@ func TestFuzzCrashers(t *testing.T) {
 	}
 }
 
+func TestParseMessageWithBadLength(t *testing.T) {
+	type testCase struct {
+		fname string
+		data  []byte
+	}
+
+	var cases []testCase
+	root := filepath.Join("testdata", "bad-len")
+	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			if path == root {
+				return nil
+			}
+			return filepath.SkipDir
+		}
+		fname := filepath.Base(path)
+		if strings.ContainsRune(fname, '.') {
+			return nil
+		}
+		data, err := ioutil.ReadFile(path)
+		if err != nil {
+			return err
+		}
+		cases = append(cases, testCase{
+			fname: fname,
+			data:  data,
+		})
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.fname, func(t *testing.T) {
+			msg, err := ParseBGPMessage(tt.data)
+			if err == nil {
+				_, err = msg.Serialize()
+				if err != nil {
+					t.Fatal("failed to serialize:", err)
+				}
+				return
+			}
+
+			switch e := err.(type) {
+			case *MessageError:
+				switch e.TypeCode {
+				case BGP_ERROR_MESSAGE_HEADER_ERROR:
+					if e.SubTypeCode != BGP_ERROR_SUB_BAD_MESSAGE_LENGTH {
+						t.Fatalf("got unexpected message type and data: %v", e)
+					}
+				}
+			default:
+				t.Fatalf("got unwxpected error type %T: %v", err, err)
+			}
+
+		})
+	}
+}
+
 func TestNormalizeFlowSpecOpValues(t *testing.T) {
 	tests := []struct {
 		msg  string
diff --git a/pkg/packet/bgp/prefix_sid.go b/pkg/packet/bgp/prefix_sid.go
index a7983bcd..32f575ee 100644
--- a/pkg/packet/bgp/prefix_sid.go
+++ b/pkg/packet/bgp/prefix_sid.go
@@ -52,7 +52,7 @@ func (s *TLV) DecodeFromBytes(data []byte) ([]byte, error) {
 	p++
 	s.Length = binary.BigEndian.Uint16(data[p : p+2])
 
-	if len(data) < s.Len() {
+	if s.Len() < prefixSIDtlvHdrLen || len(data) < s.Len() {
 		return nil, malformedAttrListErr("decoding failed: Prefix SID TLV malformed")
 	}
 
diff --git a/pkg/packet/bgp/sr_policy.go b/pkg/packet/bgp/sr_policy.go
index e7baa069..cdd89db2 100644
--- a/pkg/packet/bgp/sr_policy.go
+++ b/pkg/packet/bgp/sr_policy.go
@@ -742,9 +742,12 @@ func (t *TunnelEncapSubTLVSRSegmentList) DecodeFromBytes(data []byte) error {
 	if err != nil {
 		return NewMessageError(BGP_ERROR_UPDATE_MESSAGE_ERROR, BGP_ERROR_SUB_MALFORMED_ATTRIBUTE_LIST, nil, err.Error())
 	}
+	if len(value) < 1 {
+		return NewMessageError(BGP_ERROR_MESSAGE_HEADER_ERROR, BGP_ERROR_SUB_BAD_MESSAGE_LENGTH, nil, "Malformed BGP message")
+	}
 	// Skip reserved byte to access inner SubTLV type
 	value = value[1:]
-	segments := make([]TunnelEncapSubTLVInterface, 0)
+	var segments []TunnelEncapSubTLVInterface
 	p := 0
 	for p < t.TunnelEncapSubTLV.Len()-4 {
 		var segment TunnelEncapSubTLVInterface
diff --git a/pkg/packet/bgp/testdata/bad-len/000852858287eb2ece5cd12aabef453f87b77adb b/pkg/packet/bgp/testdata/bad-len/000852858287eb2ece5cd12aabef453f87b77adb
new file mode 100644
index 00000000..9fed8106
--- /dev/null
+++ b/pkg/packet/bgp/testdata/bad-len/000852858287eb2ece5cd12aabef453f87b77adb
diff --git a/pkg/packet/bgp/testdata/bad-len/0b229debaa2fc1e8b997c9894ad3184cce8c7bb4 b/pkg/packet/bgp/testdata/bad-len/0b229debaa2fc1e8b997c9894ad3184cce8c7bb4
new file mode 100644
index 00000000..468f2e89
--- /dev/null
+++ b/pkg/packet/bgp/testdata/bad-len/0b229debaa2fc1e8b997c9894ad3184cce8c7bb4
diff --git a/pkg/packet/bgp/testdata/bad-len/1d1fb484828b4f23af3ff0ab71b67682d5876fd6 b/pkg/packet/bgp/testdata/bad-len/1d1fb484828b4f23af3ff0ab71b67682d5876fd6
new file mode 100644
index 00000000..416d4be8
--- /dev/null
+++ b/pkg/packet/bgp/testdata/bad-len/1d1fb484828b4f23af3ff0ab71b67682d5876fd6
diff --git a/pkg/packet/bgp/testdata/bad-len/3765bb2392d48ca8edaf0b5e39209eb2d1b87c53 b/pkg/packet/bgp/testdata/bad-len/3765bb2392d48ca8edaf0b5e39209eb2d1b87c53
new file mode 100644
index 00000000..68afda16
--- /dev/null
+++ b/pkg/packet/bgp/testdata/bad-len/3765bb2392d48ca8edaf0b5e39209eb2d1b87c53
diff --git a/pkg/packet/bgp/testdata/bad-len/4d4dc736bc89bf41363774d282b8a7641c3e7a98 b/pkg/packet/bgp/testdata/bad-len/4d4dc736bc89bf41363774d282b8a7641c3e7a98
new file mode 100644
index 00000000..4beb9d2c
--- /dev/null
+++ b/pkg/packet/bgp/testdata/bad-len/4d4dc736bc89bf41363774d282b8a7641c3e7a98