81 lines
1.9 KiB
Go
81 lines
1.9 KiB
Go
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package crypto
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import (
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"encoding/binary"
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"errors"
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"github.com/lucas-clemente/fnv128a"
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"github.com/lucas-clemente/quic-go/protocol"
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)
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// nullAEAD handles not-yet encrypted packets
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type nullAEAD struct {
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perspective protocol.Perspective
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version protocol.VersionNumber
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}
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var _ AEAD = &nullAEAD{}
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// NewNullAEAD creates a NullAEAD
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func NewNullAEAD(p protocol.Perspective, v protocol.VersionNumber) AEAD {
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return &nullAEAD{
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perspective: p,
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version: v,
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}
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}
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// Open and verify the ciphertext
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func (n *nullAEAD) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, error) {
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if len(src) < 12 {
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return nil, errors.New("NullAEAD: ciphertext cannot be less than 12 bytes long")
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}
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hash := fnv128a.New()
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hash.Write(associatedData)
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hash.Write(src[12:])
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if n.version >= protocol.Version37 {
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if n.perspective == protocol.PerspectiveServer {
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hash.Write([]byte("Client"))
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} else {
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hash.Write([]byte("Server"))
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}
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}
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testHigh, testLow := hash.Sum128()
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low := binary.LittleEndian.Uint64(src)
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high := binary.LittleEndian.Uint32(src[8:])
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if uint32(testHigh&0xffffffff) != high || testLow != low {
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return nil, errors.New("NullAEAD: failed to authenticate received data")
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}
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return src[12:], nil
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}
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// Seal writes hash and ciphertext to the buffer
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func (n *nullAEAD) Seal(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) []byte {
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if cap(dst) < 12+len(src) {
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dst = make([]byte, 12+len(src))
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} else {
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dst = dst[:12+len(src)]
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}
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hash := fnv128a.New()
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hash.Write(associatedData)
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hash.Write(src)
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if n.version >= protocol.Version37 {
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if n.perspective == protocol.PerspectiveServer {
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hash.Write([]byte("Server"))
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} else {
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hash.Write([]byte("Client"))
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}
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}
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high, low := hash.Sum128()
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copy(dst[12:], src)
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binary.LittleEndian.PutUint64(dst, low)
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binary.LittleEndian.PutUint32(dst[8:], uint32(high))
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return dst
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}
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