Insert padding with empty content to camouflage VLESS header (#1610)

This only affects the Vision client for protocols expecting server to send data first.
The change is compatible with existing version of Vision server.
This commit is contained in:
yuhan6665 2023-02-06 01:45:09 -05:00 committed by GitHub
parent 00c9576118
commit c3faa8b7ac
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2 changed files with 22 additions and 9 deletions

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@ -506,25 +506,31 @@ func ReshapeMultiBuffer(ctx context.Context, buffer buf.MultiBuffer) buf.MultiBu
// XtlsPadding add padding to eliminate length siganature during tls handshake
func XtlsPadding(b *buf.Buffer, command byte, userUUID *[]byte, ctx context.Context) *buf.Buffer {
var length int32 = 0
if b.Len() < 900 {
var contantLen int32 = 0
var paddingLen int32 = 0
if b != nil {
contantLen = b.Len()
}
if contantLen < 900 {
l, err := rand.Int(rand.Reader, big.NewInt(500))
if err != nil {
newError("failed to generate padding").Base(err).WriteToLog(session.ExportIDToError(ctx))
}
length = int32(l.Int64()) + 900 - b.Len()
paddingLen = int32(l.Int64()) + 900 - contantLen
}
newbuffer := buf.New()
if userUUID != nil {
newbuffer.Write(*userUUID)
*userUUID = nil
}
newbuffer.Write([]byte{command, byte(b.Len() >> 8), byte(b.Len()), byte(length >> 8), byte(length)})
newbuffer.Write(b.Bytes())
newbuffer.Extend(length)
newError("XtlsPadding ", b.Len(), " ", length, " ", command).WriteToLog(session.ExportIDToError(ctx))
b.Release()
b = nil
newbuffer.Write([]byte{command, byte(contantLen >> 8), byte(contantLen), byte(paddingLen >> 8), byte(paddingLen)})
if (b != nil) {
newbuffer.Write(b.Bytes())
b.Release()
b = nil
}
newbuffer.Extend(paddingLen)
newError("XtlsPadding ", contantLen, " ", paddingLen, " ", command).WriteToLog(session.ExportIDToError(ctx))
return newbuffer
}