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/* packet-peap.c
* Routines for PEAP (Protected Extensible Authentication Protocol)
* draft-kamath-pppext-peapv0
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <stdio.h>
#include <epan/packet.h>
#include <epan/eap.h>
#include <epan/expert.h>
#include <wsutil/pint.h>
#include <epan/proto_data.h>
void proto_register_peap(void);
void proto_reg_handoff_peap(void);
static int proto_peap = -1;
static int proto_eap = -1;
static dissector_handle_t peap_handle;
static dissector_handle_t eap_handle;
/*
From draft-kamath-pppext-peapv0, sec 1.1
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Identifier | Length | <-- NOT sent
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Value...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This matches the format of an EAP header but...
* 'Code', 'Identifier' and 'Length' are NOT sent over the wire
* 'Code' and 'Identifier' are extracted from the *outer* EAP header
* 'Length' is derived from the PEAP packet (ie. TLS data frame)
* ...when 'Type' is 33, the full EAP header is sent
*/
#define EAP_TLS_FLAGS_OFFSET 5
#define EAP_TLS_FLAGS_VERSION 0x07 /* mask */
static int
dissect_peap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
int version;
int len;
int offset = 0;
tvbuff_t *eap_tvb, *eap_len_tvb, *next_tvb;
guchar *eap_len_buf;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "PEAP");
col_clear(pinfo->cinfo, COL_INFO);
len = tvb_reported_length(tvb);
eap_tvb = (tvbuff_t *)p_get_proto_data(pinfo->pool, pinfo, proto_eap, PROTO_DATA_EAP_TVB);
version = tvb_get_guint8(eap_tvb, EAP_TLS_FLAGS_OFFSET) & EAP_TLS_FLAGS_VERSION;
if (version > 0) { /* FIXME support v1 and v2 */
goto ret;
}
if (!( len >= 5
&& tvb_get_bits(tvb, offset, 16, ENC_BIG_ENDIAN) == tvb_get_bits(eap_tvb, 0, 16, ENC_BIG_ENDIAN)
&& tvb_get_guint16(tvb, offset + 2, ENC_BIG_ENDIAN) <= tvb_get_guint16(eap_tvb, 2, ENC_BIG_ENDIAN)
&& (
(tvb_get_guint8(eap_tvb, 0) == EAP_REQUEST && tvb_get_guint8(tvb, offset + 4) == EAP_TYPE_ID)
|| tvb_get_guint8(tvb, offset + 4) == EAP_TYPE_MSAUTH_TLV
))) {
eap_len_buf = (guchar *)wmem_alloc(pinfo->pool, 2);
eap_len_tvb = tvb_new_child_real_data(tvb, eap_len_buf, 2, 2);
phton16(eap_len_buf, 4 + len);
next_tvb = tvb_new_composite();
tvb_composite_append(next_tvb, tvb_new_subset_length(eap_tvb, 0, 2));
tvb_composite_append(next_tvb, eap_len_tvb);
tvb_composite_append(next_tvb, tvb_new_subset_length(tvb, offset, 4 + len));
tvb_composite_finalize(next_tvb);
add_new_data_source(pinfo, next_tvb, "Pseudo EAP");
} else {
next_tvb = tvb;
}
call_dissector(eap_handle, next_tvb, pinfo, tree);
ret:
return len;
}
void
proto_register_peap(void)
{
proto_peap = proto_register_protocol("Protected Extensible Authentication Protocol",
"PEAP", "peap");
peap_handle = register_dissector("peap", dissect_peap, proto_peap);
}
void
proto_reg_handoff_peap(void)
{
proto_eap = proto_get_id_by_filter_name("eap");
eap_handle = find_dissector_add_dependency("eap", proto_peap);
}
/*
* Editor modelines
*
* Local Variables:
* c-basic-offset: 2
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* ex: set shiftwidth=2 tabstop=8 expandtab:
* :indentSize=2:tabSize=8:noTabs=true:
*/
|
