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p2p/discover/v5wire: reject packets if smaller than 63 bytes #25740

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Merged
merged 2 commits into from
Sep 12, 2022
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p2p/discover/v5wire: reject packets if smaller than 63 bytes #25740

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04b6816
p2p/discover: reject packets if smaller than 63 bytes
dbadoy Sep 12, 2022
cbf7c34
test codes
dbadoy Sep 12, 2022
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8 changes: 6 additions & 2 deletions p2p/discover/v5wire/encoding.go
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Original file line number Diff line number Diff line change
Expand Up @@ -90,6 +90,10 @@ const (
minVersion = 1
sizeofMaskingIV = 16

// The minimum size of any Discovery v5 packet is 63 bytes.
// Should reject packets smaller than minPacketSize.
minPacketSize = 63

minMessageSize = 48 // this refers to data after static headers
randomPacketMsgSize = 20
)
Expand Down Expand Up @@ -415,10 +419,10 @@ func (c *Codec) encryptMessage(s *session, p Packet, head *Header, headerData []

// Decode decodes a discovery packet.
func (c *Codec) Decode(input []byte, addr string) (src enode.ID, n *enode.Node, p Packet, err error) {
// Unmask the static header.
if len(input) < sizeofStaticPacketData {
if len(input) < minPacketSize {
return enode.ID{}, nil, nil, errTooShort
}
// Unmask the static header.
var head Header
copy(head.IV[:], input[:sizeofMaskingIV])
mask := head.mask(c.localnode.ID())
Expand Down
10 changes: 9 additions & 1 deletion p2p/discover/v5wire/encoding_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -275,7 +275,15 @@ func TestDecodeErrorsV5(t *testing.T) {
net := newHandshakeTest()
defer net.close()

net.nodeA.expectDecodeErr(t, errTooShort, []byte{})
b := make([]byte, 0)
net.nodeA.expectDecodeErr(t, errTooShort, b)

b = make([]byte, 62)
net.nodeA.expectDecodeErr(t, errTooShort, b)

b = make([]byte, 63)
net.nodeA.expectDecodeErr(t, errInvalidHeader, b)

// TODO some more tests would be nice :)
// - check invalid authdata sizes
// - check invalid handshake data sizes
Expand Down