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