PPPD buffer overflow in PEAP response code

The code in pppd that formats a response to a PEAP Request packet in peap_response() copies an entire TLS record of up to 16384 bytes into the fixed global buffer outpacket_buf without checking the available space and without implementing outgoing PEAP fragmentation. Thus a pppd process connecting to a server which requests PEAP authentication can be induced to corrupt global static data following the outpacket_buf array, most likely causing incorrect behavior or a crash.