handle_pap(netdissect_options *ndo,
           const u_char *p, int length)
{
	u_int code, len;
	int peerid_len, passwd_len, msg_len;
	const u_char *p0;
	int i;

	p0 = p;
	if (length < 1) {
		ND_PRINT((ndo, "[|pap]"));
		return;
	} else if (length < 4) {
		ND_TCHECK(*p);
		ND_PRINT((ndo, "[|pap 0x%02x]", *p));
		return;
	}

	ND_TCHECK(*p);
	code = *p;
	ND_PRINT((ndo, "PAP, %s (0x%02x)",
	          tok2str(papcode_values, "unknown", code),
	          code));
	p++;

	ND_TCHECK(*p);
	ND_PRINT((ndo, ", id %u", *p));		/* ID */
	p++;

	ND_TCHECK2(*p, 2);
	len = EXTRACT_16BITS(p);
	p += 2;

	if ((int)len > length) {
		ND_PRINT((ndo, ", length %u > packet size", len));
		return;
	}
	length = len;
	if (length < (p - p0)) {
		ND_PRINT((ndo, ", length %u < PAP header length", length));
		return;
	}

	switch (code) {
	case PAP_AREQ:
		if (length - (p - p0) < 1)
			return;
		ND_TCHECK(*p);
		peerid_len = *p;	/* Peer-ID Length */
		p++;
		if (length - (p - p0) < peerid_len)
			return;
		ND_PRINT((ndo, ", Peer "));
		for (i = 0; i < peerid_len; i++) {
			ND_TCHECK(*p);
			safeputchar(ndo, *p++);
		}

		if (length - (p - p0) < 1)
			return;
		ND_TCHECK(*p);
		passwd_len = *p;	/* Password Length */
		p++;
		if (length - (p - p0) < passwd_len)
			return;
		ND_PRINT((ndo, ", Name "));
		for (i = 0; i < passwd_len; i++) {
			ND_TCHECK(*p);
			safeputchar(ndo, *p++);
		}
		break;
	case PAP_AACK:
	case PAP_ANAK:
		if (length - (p - p0) < 1)
			return;
		ND_TCHECK(*p);
		msg_len = *p;		/* Msg-Length */
		p++;
		if (length - (p - p0) < msg_len)
			return;
		ND_PRINT((ndo, ", Msg "));
		for (i = 0; i< msg_len; i++) {
			ND_TCHECK(*p);
			safeputchar(ndo, *p++);
		}
		break;
	}
	return;

trunc:
	ND_PRINT((ndo, "[|pap]"));
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.