Neels Hofmeyr | d739f09 | 2015-10-12 11:57:34 +0200 | [diff] [blame] | 1 | /* Osmocom Authentication Protocol message encoder/decoder */ |
| 2 | |
| 3 | /* (C) 2015 by Sysmocom s.f.m.c. GmbH |
| 4 | * All Rights Reserved |
| 5 | * |
| 6 | * Author: Neels Hofmeyr |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU Affero General Public License as published by |
| 10 | * the Free Software Foundation; either version 3 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU Affero General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Affero General Public License |
| 19 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 20 | * |
| 21 | */ |
| 22 | |
Harald Welte | 50f1c0a | 2016-04-25 19:01:26 +0200 | [diff] [blame] | 23 | #include <osmocom/core/utils.h> |
Neels Hofmeyr | d739f09 | 2015-10-12 11:57:34 +0200 | [diff] [blame] | 24 | #include <openbsc/oap_messages.h> |
| 25 | |
| 26 | #include <openbsc/debug.h> |
| 27 | #include <openbsc/gprs_utils.h> |
Neels Hofmeyr | d739f09 | 2015-10-12 11:57:34 +0200 | [diff] [blame] | 28 | |
| 29 | #include <osmocom/gsm/tlv.h> |
| 30 | #include <osmocom/core/msgb.h> |
| 31 | |
| 32 | #include <stdint.h> |
| 33 | |
| 34 | |
| 35 | int oap_decode(const uint8_t *const_data, size_t data_len, |
| 36 | struct oap_message *oap_msg) |
| 37 | { |
| 38 | int rc; |
| 39 | uint8_t tag; |
| 40 | /* the shift/match functions expect non-const pointers, but we'll |
| 41 | * either copy the data or cast pointers back to const before returning |
| 42 | * them |
| 43 | */ |
| 44 | uint8_t *data = (uint8_t *)const_data; |
| 45 | uint8_t *value; |
| 46 | size_t value_len; |
| 47 | |
| 48 | memset(oap_msg, 0, sizeof(*oap_msg)); |
| 49 | |
| 50 | /* message type */ |
Harald Welte | 842674b | 2016-04-25 15:14:01 +0200 | [diff] [blame] | 51 | rc = osmo_shift_v_fixed(&data, &data_len, 1, &value); |
Neels Hofmeyr | d739f09 | 2015-10-12 11:57:34 +0200 | [diff] [blame] | 52 | if (rc < 0) |
| 53 | return -GMM_CAUSE_INV_MAND_INFO; |
Harald Welte | 50f1c0a | 2016-04-25 19:01:26 +0200 | [diff] [blame] | 54 | oap_msg->message_type = osmo_decode_big_endian(value, 1); |
Neels Hofmeyr | d739f09 | 2015-10-12 11:57:34 +0200 | [diff] [blame] | 55 | |
| 56 | /* specific parts */ |
| 57 | while (data_len > 0) { |
| 58 | enum oap_iei iei; |
| 59 | |
Harald Welte | 842674b | 2016-04-25 15:14:01 +0200 | [diff] [blame] | 60 | rc = osmo_shift_tlv(&data, &data_len, &tag, &value, &value_len); |
Neels Hofmeyr | d739f09 | 2015-10-12 11:57:34 +0200 | [diff] [blame] | 61 | if (rc < 0) |
| 62 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 63 | |
| 64 | iei = tag; |
| 65 | |
| 66 | switch (iei) { |
| 67 | case OAP_CLIENT_ID_IE: |
| 68 | if (value_len != 2) { |
| 69 | LOGP(DGPRS, LOGL_NOTICE, |
| 70 | "OAP IE type client ID (%d) should be 2 octets, but has %d\n", |
| 71 | (int)iei, (int)value_len); |
| 72 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 73 | } |
| 74 | |
Harald Welte | 50f1c0a | 2016-04-25 19:01:26 +0200 | [diff] [blame] | 75 | oap_msg->client_id = osmo_decode_big_endian(value, value_len); |
Neels Hofmeyr | d739f09 | 2015-10-12 11:57:34 +0200 | [diff] [blame] | 76 | |
| 77 | if (oap_msg->client_id == 0) { |
| 78 | LOGP(DGPRS, LOGL_NOTICE, |
| 79 | "OAP IE type client ID (%d): client ID must be nonzero.\n", |
| 80 | (int)iei); |
| 81 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 82 | } |
| 83 | break; |
| 84 | |
| 85 | case OAP_AUTN_IE: |
| 86 | if (value_len != sizeof(oap_msg->autn)) { |
| 87 | LOGP(DGPRS, LOGL_NOTICE, |
| 88 | "OAP IE type AUTN (%d) should be %d octets, but has %d\n", |
| 89 | (int)iei, (int)sizeof(oap_msg->autn), (int)value_len); |
| 90 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 91 | } |
| 92 | memcpy(oap_msg->autn, value, value_len); |
| 93 | oap_msg->autn_present = value_len; |
| 94 | break; |
| 95 | |
| 96 | case OAP_RAND_IE: |
| 97 | if (value_len != sizeof(oap_msg->rand)) { |
| 98 | LOGP(DGPRS, LOGL_NOTICE, |
| 99 | "OAP IE type RAND (%d) should be %d octets, but has %d\n", |
| 100 | (int)iei, (int)sizeof(oap_msg->rand), (int)value_len); |
| 101 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 102 | } |
| 103 | memcpy(oap_msg->rand, value, value_len); |
| 104 | oap_msg->rand_present = value_len; |
| 105 | break; |
| 106 | |
| 107 | case OAP_XRES_IE: |
| 108 | if (value_len != sizeof(oap_msg->xres)) { |
| 109 | LOGP(DGPRS, LOGL_NOTICE, |
| 110 | "OAP IE type XRES (%d) should be %d octets, but has %d\n", |
| 111 | (int)iei, (int)sizeof(oap_msg->xres), (int)value_len); |
| 112 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 113 | } |
| 114 | memcpy(oap_msg->xres, value, value_len); |
| 115 | oap_msg->xres_present = value_len; |
| 116 | break; |
| 117 | |
| 118 | case OAP_AUTS_IE: |
| 119 | if (value_len != sizeof(oap_msg->auts)) { |
| 120 | LOGP(DGPRS, LOGL_NOTICE, |
| 121 | "OAP IE type AUTS (%d) should be %d octets, but has %d\n", |
| 122 | (int)iei, (int)sizeof(oap_msg->auts), (int)value_len); |
| 123 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 124 | } |
| 125 | memcpy(oap_msg->auts, value, value_len); |
| 126 | oap_msg->auts_present = value_len; |
| 127 | break; |
| 128 | |
| 129 | case OAP_CAUSE_IE: |
| 130 | if (value_len > 1) { |
| 131 | LOGP(DGPRS, LOGL_ERROR, |
| 132 | "OAP cause may not exceed one octet, is %d", (int)value_len); |
| 133 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 134 | } |
| 135 | oap_msg->cause = *value; |
| 136 | break; |
| 137 | |
| 138 | default: |
| 139 | LOGP(DGPRS, LOGL_NOTICE, |
| 140 | "OAP IE type %d unknown\n", iei); |
| 141 | continue; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | return 0; |
| 146 | } |
| 147 | |
| 148 | void oap_encode(struct msgb *msg, const struct oap_message *oap_msg) |
| 149 | { |
| 150 | uint8_t u8; |
| 151 | |
| 152 | /* generic part */ |
| 153 | OSMO_ASSERT(oap_msg->message_type); |
| 154 | msgb_v_put(msg, (uint8_t)oap_msg->message_type); |
| 155 | |
| 156 | /* specific parts */ |
| 157 | if ((u8 = oap_msg->cause)) |
| 158 | msgb_tlv_put(msg, OAP_CAUSE_IE, sizeof(u8), &u8); |
| 159 | |
| 160 | if (oap_msg->client_id > 0) |
| 161 | msgb_tlv_put(msg, OAP_CLIENT_ID_IE, sizeof(oap_msg->client_id), |
Harald Welte | 50f1c0a | 2016-04-25 19:01:26 +0200 | [diff] [blame] | 162 | osmo_encode_big_endian(oap_msg->client_id, |
| 163 | sizeof(oap_msg->client_id))); |
Neels Hofmeyr | d739f09 | 2015-10-12 11:57:34 +0200 | [diff] [blame] | 164 | |
| 165 | if (oap_msg->rand_present) |
| 166 | msgb_tlv_put(msg, OAP_RAND_IE, sizeof(oap_msg->rand), oap_msg->rand); |
| 167 | |
| 168 | if (oap_msg->autn_present) |
| 169 | msgb_tlv_put(msg, OAP_AUTN_IE, sizeof(oap_msg->autn), oap_msg->autn); |
| 170 | |
| 171 | if (oap_msg->auts_present) |
| 172 | msgb_tlv_put(msg, OAP_AUTS_IE, sizeof(oap_msg->auts), oap_msg->auts); |
| 173 | |
| 174 | if (oap_msg->xres_present) |
| 175 | msgb_tlv_put(msg, OAP_XRES_IE, sizeof(oap_msg->xres), oap_msg->xres); |
| 176 | |
| 177 | msg->l2h = msg->data; |
| 178 | } |
| 179 | |