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client-hello-mirror
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add extra handshake message checks

This commit is contained in:
nervuri 2023-03-24 16:32:02 +00:00
parent 43900e63a4
commit 7af54c28e1
1 changed files with 11 additions and 1 deletions
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12
server.go
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@ -80,7 +80,11 @@ func peek(conn net.Conn, tlsConfig *tls.Config) {
}
// Extract handshake message length.
handshakeMessageLength := binary.BigEndian.Uint16(buf.Bytes()[3:5])
// Copy handshake message (should be a Client Hello).
if handshakeMessageLength == 0 {
log.Println("Zero-length handshake message")
return
}
// Copy handshake message.
_, err = io.CopyN(&buf, conn, int64(handshakeMessageLength))
if err != nil {
log.Println(err)
@ -88,6 +92,12 @@ func peek(conn net.Conn, tlsConfig *tls.Config) {
}
rawClientHello := buf.Bytes()
// Check if this really is a Client Hello message.
if rawClientHello[5] != 1 {
log.Println("HandshakeType is not client_hello")
return
}
// "Put back" the Client Hello bytes we just read, so that they can be
// used in the TLS handshake. Concatenate the read bytes with the
// unread bytes using a MultiReader, inside a connection wrapper.