1*ed775ee7SAntonio Huete Jimenez /* Copyright (c) 2017, Sabrina Dubroca <sd@queasysnail.net>
2*ed775ee7SAntonio Huete Jimenez *
3*ed775ee7SAntonio Huete Jimenez * Redistribution and use in source and binary forms, with or without
4*ed775ee7SAntonio Huete Jimenez * modification, are permitted provided that the following conditions
5*ed775ee7SAntonio Huete Jimenez * are met:
6*ed775ee7SAntonio Huete Jimenez *
7*ed775ee7SAntonio Huete Jimenez * 1. Redistributions of source code must retain the above copyright
8*ed775ee7SAntonio Huete Jimenez * notice, this list of conditions and the following disclaimer.
9*ed775ee7SAntonio Huete Jimenez * 2. Redistributions in binary form must reproduce the above copyright
10*ed775ee7SAntonio Huete Jimenez * notice, this list of conditions and the following disclaimer in
11*ed775ee7SAntonio Huete Jimenez * the documentation and/or other materials provided with the
12*ed775ee7SAntonio Huete Jimenez * distribution.
13*ed775ee7SAntonio Huete Jimenez * 3. The names of the authors may not be used to endorse or promote
14*ed775ee7SAntonio Huete Jimenez * products derived from this software without specific prior
15*ed775ee7SAntonio Huete Jimenez * written permission.
16*ed775ee7SAntonio Huete Jimenez *
17*ed775ee7SAntonio Huete Jimenez * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
18*ed775ee7SAntonio Huete Jimenez * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
19*ed775ee7SAntonio Huete Jimenez * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20*ed775ee7SAntonio Huete Jimenez */
21*ed775ee7SAntonio Huete Jimenez
22*ed775ee7SAntonio Huete Jimenez /* \summary: MACsec printer */
23*ed775ee7SAntonio Huete Jimenez
24*ed775ee7SAntonio Huete Jimenez #ifdef HAVE_CONFIG_H
25*ed775ee7SAntonio Huete Jimenez #include <config.h>
26*ed775ee7SAntonio Huete Jimenez #endif
27*ed775ee7SAntonio Huete Jimenez
28*ed775ee7SAntonio Huete Jimenez #include "netdissect-stdinc.h"
29*ed775ee7SAntonio Huete Jimenez
30*ed775ee7SAntonio Huete Jimenez #include "netdissect.h"
31*ed775ee7SAntonio Huete Jimenez #include "addrtoname.h"
32*ed775ee7SAntonio Huete Jimenez #include "ethertype.h"
33*ed775ee7SAntonio Huete Jimenez #include "extract.h"
34*ed775ee7SAntonio Huete Jimenez
35*ed775ee7SAntonio Huete Jimenez #define MACSEC_DEFAULT_ICV_LEN 16
36*ed775ee7SAntonio Huete Jimenez
37*ed775ee7SAntonio Huete Jimenez /* Header format (SecTAG), following an Ethernet header
38*ed775ee7SAntonio Huete Jimenez * IEEE 802.1AE-2006 9.3
39*ed775ee7SAntonio Huete Jimenez *
40*ed775ee7SAntonio Huete Jimenez * +---------------------------------+----------------+----------------+
41*ed775ee7SAntonio Huete Jimenez * | (MACsec ethertype) | TCI_AN | SL |
42*ed775ee7SAntonio Huete Jimenez * +---------------------------------+----------------+----------------+
43*ed775ee7SAntonio Huete Jimenez * | Packet Number |
44*ed775ee7SAntonio Huete Jimenez * +-------------------------------------------------------------------+
45*ed775ee7SAntonio Huete Jimenez * | Secure Channel Identifier |
46*ed775ee7SAntonio Huete Jimenez * | (optional) |
47*ed775ee7SAntonio Huete Jimenez * +-------------------------------------------------------------------+
48*ed775ee7SAntonio Huete Jimenez *
49*ed775ee7SAntonio Huete Jimenez * MACsec ethertype = 0x88e5
50*ed775ee7SAntonio Huete Jimenez * TCI: Tag Control Information, set of flags
51*ed775ee7SAntonio Huete Jimenez * AN: association number, 2 bits
52*ed775ee7SAntonio Huete Jimenez * SL (short length): 6-bit length of the protected payload, if < 48
53*ed775ee7SAntonio Huete Jimenez * Packet Number: 32-bits packet identifier
54*ed775ee7SAntonio Huete Jimenez * Secure Channel Identifier: 64-bit unique identifier, usually
55*ed775ee7SAntonio Huete Jimenez * composed of a MAC address + 16-bit port number
56*ed775ee7SAntonio Huete Jimenez */
57*ed775ee7SAntonio Huete Jimenez struct macsec_sectag {
58*ed775ee7SAntonio Huete Jimenez nd_uint8_t tci_an;
59*ed775ee7SAntonio Huete Jimenez nd_uint8_t short_length;
60*ed775ee7SAntonio Huete Jimenez nd_uint32_t packet_number;
61*ed775ee7SAntonio Huete Jimenez nd_uint8_t secure_channel_id[8]; /* optional */
62*ed775ee7SAntonio Huete Jimenez };
63*ed775ee7SAntonio Huete Jimenez
64*ed775ee7SAntonio Huete Jimenez /* IEEE 802.1AE-2006 9.5 */
65*ed775ee7SAntonio Huete Jimenez #define MACSEC_TCI_VERSION 0x80
66*ed775ee7SAntonio Huete Jimenez #define MACSEC_TCI_ES 0x40 /* end station */
67*ed775ee7SAntonio Huete Jimenez #define MACSEC_TCI_SC 0x20 /* SCI present */
68*ed775ee7SAntonio Huete Jimenez #define MACSEC_TCI_SCB 0x10 /* epon */
69*ed775ee7SAntonio Huete Jimenez #define MACSEC_TCI_E 0x08 /* encryption */
70*ed775ee7SAntonio Huete Jimenez #define MACSEC_TCI_C 0x04 /* changed text */
71*ed775ee7SAntonio Huete Jimenez #define MACSEC_AN_MASK 0x03 /* association number */
72*ed775ee7SAntonio Huete Jimenez #define MACSEC_TCI_FLAGS (MACSEC_TCI_ES | MACSEC_TCI_SC | MACSEC_TCI_SCB | MACSEC_TCI_E | MACSEC_TCI_C)
73*ed775ee7SAntonio Huete Jimenez #define MACSEC_TCI_CONFID (MACSEC_TCI_E | MACSEC_TCI_C)
74*ed775ee7SAntonio Huete Jimenez #define MACSEC_SL_MASK 0x3F /* short length */
75*ed775ee7SAntonio Huete Jimenez
76*ed775ee7SAntonio Huete Jimenez #define MACSEC_SECTAG_LEN_NOSCI 6 /* length of MACsec header without SCI */
77*ed775ee7SAntonio Huete Jimenez #define MACSEC_SECTAG_LEN_SCI 14 /* length of MACsec header with SCI */
78*ed775ee7SAntonio Huete Jimenez
79*ed775ee7SAntonio Huete Jimenez #define SCI_FMT "%016" PRIx64
80*ed775ee7SAntonio Huete Jimenez
81*ed775ee7SAntonio Huete Jimenez static const struct tok macsec_flag_values[] = {
82*ed775ee7SAntonio Huete Jimenez { MACSEC_TCI_E, "E" },
83*ed775ee7SAntonio Huete Jimenez { MACSEC_TCI_C, "C" },
84*ed775ee7SAntonio Huete Jimenez { MACSEC_TCI_ES, "S" },
85*ed775ee7SAntonio Huete Jimenez { MACSEC_TCI_SCB, "B" },
86*ed775ee7SAntonio Huete Jimenez { MACSEC_TCI_SC, "I" },
87*ed775ee7SAntonio Huete Jimenez { 0, NULL }
88*ed775ee7SAntonio Huete Jimenez };
89*ed775ee7SAntonio Huete Jimenez
macsec_print_header(netdissect_options * ndo,const struct macsec_sectag * sectag,u_int short_length)90*ed775ee7SAntonio Huete Jimenez static void macsec_print_header(netdissect_options *ndo,
91*ed775ee7SAntonio Huete Jimenez const struct macsec_sectag *sectag,
92*ed775ee7SAntonio Huete Jimenez u_int short_length)
93*ed775ee7SAntonio Huete Jimenez {
94*ed775ee7SAntonio Huete Jimenez ND_PRINT("an %u, pn %u, flags %s",
95*ed775ee7SAntonio Huete Jimenez GET_U_1(sectag->tci_an) & MACSEC_AN_MASK,
96*ed775ee7SAntonio Huete Jimenez GET_BE_U_4(sectag->packet_number),
97*ed775ee7SAntonio Huete Jimenez bittok2str_nosep(macsec_flag_values, "none",
98*ed775ee7SAntonio Huete Jimenez GET_U_1(sectag->tci_an) & MACSEC_TCI_FLAGS));
99*ed775ee7SAntonio Huete Jimenez
100*ed775ee7SAntonio Huete Jimenez if (short_length != 0)
101*ed775ee7SAntonio Huete Jimenez ND_PRINT(", sl %u", short_length);
102*ed775ee7SAntonio Huete Jimenez
103*ed775ee7SAntonio Huete Jimenez if (GET_U_1(sectag->tci_an) & MACSEC_TCI_SC)
104*ed775ee7SAntonio Huete Jimenez ND_PRINT(", sci " SCI_FMT, GET_BE_U_8(sectag->secure_channel_id));
105*ed775ee7SAntonio Huete Jimenez
106*ed775ee7SAntonio Huete Jimenez ND_PRINT(", ");
107*ed775ee7SAntonio Huete Jimenez }
108*ed775ee7SAntonio Huete Jimenez
109*ed775ee7SAntonio Huete Jimenez /* returns < 0 iff the packet can be decoded completely */
macsec_print(netdissect_options * ndo,const u_char ** bp,u_int * lengthp,u_int * caplenp,u_int * hdrlenp,const struct lladdr_info * src,const struct lladdr_info * dst)110*ed775ee7SAntonio Huete Jimenez int macsec_print(netdissect_options *ndo, const u_char **bp,
111*ed775ee7SAntonio Huete Jimenez u_int *lengthp, u_int *caplenp, u_int *hdrlenp,
112*ed775ee7SAntonio Huete Jimenez const struct lladdr_info *src, const struct lladdr_info *dst)
113*ed775ee7SAntonio Huete Jimenez {
114*ed775ee7SAntonio Huete Jimenez const char *save_protocol;
115*ed775ee7SAntonio Huete Jimenez const u_char *p = *bp;
116*ed775ee7SAntonio Huete Jimenez u_int length = *lengthp;
117*ed775ee7SAntonio Huete Jimenez u_int caplen = *caplenp;
118*ed775ee7SAntonio Huete Jimenez u_int hdrlen = *hdrlenp;
119*ed775ee7SAntonio Huete Jimenez const struct macsec_sectag *sectag = (const struct macsec_sectag *)p;
120*ed775ee7SAntonio Huete Jimenez u_int sectag_len;
121*ed775ee7SAntonio Huete Jimenez u_int short_length;
122*ed775ee7SAntonio Huete Jimenez
123*ed775ee7SAntonio Huete Jimenez save_protocol = ndo->ndo_protocol;
124*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = "macsec";
125*ed775ee7SAntonio Huete Jimenez
126*ed775ee7SAntonio Huete Jimenez /* we need the full MACsec header in the capture */
127*ed775ee7SAntonio Huete Jimenez if (caplen < MACSEC_SECTAG_LEN_NOSCI) {
128*ed775ee7SAntonio Huete Jimenez nd_print_trunc(ndo);
129*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
130*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
131*ed775ee7SAntonio Huete Jimenez }
132*ed775ee7SAntonio Huete Jimenez if (length < MACSEC_SECTAG_LEN_NOSCI) {
133*ed775ee7SAntonio Huete Jimenez nd_print_trunc(ndo);
134*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
135*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
136*ed775ee7SAntonio Huete Jimenez }
137*ed775ee7SAntonio Huete Jimenez
138*ed775ee7SAntonio Huete Jimenez if (GET_U_1(sectag->tci_an) & MACSEC_TCI_SC) {
139*ed775ee7SAntonio Huete Jimenez sectag_len = MACSEC_SECTAG_LEN_SCI;
140*ed775ee7SAntonio Huete Jimenez if (caplen < MACSEC_SECTAG_LEN_SCI) {
141*ed775ee7SAntonio Huete Jimenez nd_print_trunc(ndo);
142*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
143*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
144*ed775ee7SAntonio Huete Jimenez }
145*ed775ee7SAntonio Huete Jimenez if (length < MACSEC_SECTAG_LEN_SCI) {
146*ed775ee7SAntonio Huete Jimenez nd_print_trunc(ndo);
147*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
148*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
149*ed775ee7SAntonio Huete Jimenez }
150*ed775ee7SAntonio Huete Jimenez } else
151*ed775ee7SAntonio Huete Jimenez sectag_len = MACSEC_SECTAG_LEN_NOSCI;
152*ed775ee7SAntonio Huete Jimenez
153*ed775ee7SAntonio Huete Jimenez if ((GET_U_1(sectag->short_length) & ~MACSEC_SL_MASK) != 0 ||
154*ed775ee7SAntonio Huete Jimenez GET_U_1(sectag->tci_an) & MACSEC_TCI_VERSION) {
155*ed775ee7SAntonio Huete Jimenez nd_print_invalid(ndo);
156*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
157*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
158*ed775ee7SAntonio Huete Jimenez }
159*ed775ee7SAntonio Huete Jimenez
160*ed775ee7SAntonio Huete Jimenez short_length = GET_U_1(sectag->short_length) & MACSEC_SL_MASK;
161*ed775ee7SAntonio Huete Jimenez if (ndo->ndo_eflag)
162*ed775ee7SAntonio Huete Jimenez macsec_print_header(ndo, sectag, short_length);
163*ed775ee7SAntonio Huete Jimenez
164*ed775ee7SAntonio Huete Jimenez /* Skip the MACsec header. */
165*ed775ee7SAntonio Huete Jimenez *bp += sectag_len;
166*ed775ee7SAntonio Huete Jimenez *hdrlenp += sectag_len;
167*ed775ee7SAntonio Huete Jimenez
168*ed775ee7SAntonio Huete Jimenez /* Remove it from the lengths, as it's been processed. */
169*ed775ee7SAntonio Huete Jimenez *lengthp -= sectag_len;
170*ed775ee7SAntonio Huete Jimenez *caplenp -= sectag_len;
171*ed775ee7SAntonio Huete Jimenez
172*ed775ee7SAntonio Huete Jimenez if ((GET_U_1(sectag->tci_an) & MACSEC_TCI_CONFID)) {
173*ed775ee7SAntonio Huete Jimenez /*
174*ed775ee7SAntonio Huete Jimenez * The payload is encrypted. Print link-layer
175*ed775ee7SAntonio Huete Jimenez * information, if it hasn't already been printed.
176*ed775ee7SAntonio Huete Jimenez */
177*ed775ee7SAntonio Huete Jimenez if (!ndo->ndo_eflag) {
178*ed775ee7SAntonio Huete Jimenez /*
179*ed775ee7SAntonio Huete Jimenez * Nobody printed the link-layer addresses,
180*ed775ee7SAntonio Huete Jimenez * so print them, if we have any.
181*ed775ee7SAntonio Huete Jimenez */
182*ed775ee7SAntonio Huete Jimenez if (src != NULL && dst != NULL) {
183*ed775ee7SAntonio Huete Jimenez ND_PRINT("%s > %s ",
184*ed775ee7SAntonio Huete Jimenez (src->addr_string)(ndo, src->addr),
185*ed775ee7SAntonio Huete Jimenez (dst->addr_string)(ndo, dst->addr));
186*ed775ee7SAntonio Huete Jimenez }
187*ed775ee7SAntonio Huete Jimenez
188*ed775ee7SAntonio Huete Jimenez ND_PRINT("802.1AE MACsec, ");
189*ed775ee7SAntonio Huete Jimenez
190*ed775ee7SAntonio Huete Jimenez /*
191*ed775ee7SAntonio Huete Jimenez * Print the MACsec header.
192*ed775ee7SAntonio Huete Jimenez */
193*ed775ee7SAntonio Huete Jimenez macsec_print_header(ndo, sectag, short_length);
194*ed775ee7SAntonio Huete Jimenez }
195*ed775ee7SAntonio Huete Jimenez
196*ed775ee7SAntonio Huete Jimenez /*
197*ed775ee7SAntonio Huete Jimenez * Tell our caller it can't be dissected.
198*ed775ee7SAntonio Huete Jimenez */
199*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
200*ed775ee7SAntonio Huete Jimenez return 0;
201*ed775ee7SAntonio Huete Jimenez }
202*ed775ee7SAntonio Huete Jimenez
203*ed775ee7SAntonio Huete Jimenez /*
204*ed775ee7SAntonio Huete Jimenez * The payload isn't encrypted; remove the
205*ed775ee7SAntonio Huete Jimenez * ICV length from the lengths, so our caller
206*ed775ee7SAntonio Huete Jimenez * doesn't treat it as payload.
207*ed775ee7SAntonio Huete Jimenez */
208*ed775ee7SAntonio Huete Jimenez if (*lengthp < MACSEC_DEFAULT_ICV_LEN) {
209*ed775ee7SAntonio Huete Jimenez nd_print_trunc(ndo);
210*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
211*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
212*ed775ee7SAntonio Huete Jimenez }
213*ed775ee7SAntonio Huete Jimenez if (*caplenp < MACSEC_DEFAULT_ICV_LEN) {
214*ed775ee7SAntonio Huete Jimenez nd_print_trunc(ndo);
215*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
216*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
217*ed775ee7SAntonio Huete Jimenez }
218*ed775ee7SAntonio Huete Jimenez *lengthp -= MACSEC_DEFAULT_ICV_LEN;
219*ed775ee7SAntonio Huete Jimenez *caplenp -= MACSEC_DEFAULT_ICV_LEN;
220*ed775ee7SAntonio Huete Jimenez /*
221*ed775ee7SAntonio Huete Jimenez * Update the snapend thus the ICV field is not in the payload for
222*ed775ee7SAntonio Huete Jimenez * the caller.
223*ed775ee7SAntonio Huete Jimenez * The ICV (Integrity Check Value) is at the end of the frame, after
224*ed775ee7SAntonio Huete Jimenez * the secure data.
225*ed775ee7SAntonio Huete Jimenez */
226*ed775ee7SAntonio Huete Jimenez ndo->ndo_snapend -= MACSEC_DEFAULT_ICV_LEN;
227*ed775ee7SAntonio Huete Jimenez
228*ed775ee7SAntonio Huete Jimenez /*
229*ed775ee7SAntonio Huete Jimenez * If the SL field is non-zero, then it's the length of the
230*ed775ee7SAntonio Huete Jimenez * Secure Data; otherwise, the Secure Data is what's left
231*ed775ee7SAntonio Huete Jimenez * ver after the MACsec header and ICV are removed.
232*ed775ee7SAntonio Huete Jimenez */
233*ed775ee7SAntonio Huete Jimenez if (short_length != 0) {
234*ed775ee7SAntonio Huete Jimenez /*
235*ed775ee7SAntonio Huete Jimenez * If the short length is more than we *have*,
236*ed775ee7SAntonio Huete Jimenez * that's an error.
237*ed775ee7SAntonio Huete Jimenez */
238*ed775ee7SAntonio Huete Jimenez if (short_length > *lengthp) {
239*ed775ee7SAntonio Huete Jimenez nd_print_trunc(ndo);
240*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
241*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
242*ed775ee7SAntonio Huete Jimenez }
243*ed775ee7SAntonio Huete Jimenez if (short_length > *caplenp) {
244*ed775ee7SAntonio Huete Jimenez nd_print_trunc(ndo);
245*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
246*ed775ee7SAntonio Huete Jimenez return hdrlen + caplen;
247*ed775ee7SAntonio Huete Jimenez }
248*ed775ee7SAntonio Huete Jimenez if (*lengthp > short_length)
249*ed775ee7SAntonio Huete Jimenez *lengthp = short_length;
250*ed775ee7SAntonio Huete Jimenez if (*caplenp > short_length)
251*ed775ee7SAntonio Huete Jimenez *caplenp = short_length;
252*ed775ee7SAntonio Huete Jimenez }
253*ed775ee7SAntonio Huete Jimenez
254*ed775ee7SAntonio Huete Jimenez ndo->ndo_protocol = save_protocol;
255*ed775ee7SAntonio Huete Jimenez return -1;
256*ed775ee7SAntonio Huete Jimenez }
257