Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 1 | /* Authentication related functions */ |
| 2 | |
| 3 | /* |
| 4 | * (C) 2010 by Sylvain Munaut <tnt@246tNt.com> |
| 5 | * |
| 6 | * All Rights Reserved |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
Harald Welte | 9af6ddf | 2011-01-01 15:25:50 +0100 | [diff] [blame] | 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 |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 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 |
Harald Welte | 9af6ddf | 2011-01-01 15:25:50 +0100 | [diff] [blame] | 16 | * GNU Affero General Public License for more details. |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 17 | * |
Harald Welte | 9af6ddf | 2011-01-01 15:25:50 +0100 | [diff] [blame] | 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/>. |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <openbsc/db.h> |
| 24 | #include <openbsc/debug.h> |
Harald Welte | 86dda08 | 2010-12-23 18:07:49 +0100 | [diff] [blame] | 25 | #include <openbsc/auth.h> |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 26 | #include <openbsc/gsm_data.h> |
| 27 | |
Pablo Neira Ayuso | 136f453 | 2011-03-22 16:47:59 +0100 | [diff] [blame] | 28 | #include <osmocom/gsm/comp128.h> |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 29 | |
Daniel Willmann | 62a63f5 | 2015-10-08 16:10:25 +0200 | [diff] [blame] | 30 | #include <openssl/rand.h> |
| 31 | |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 32 | #include <stdlib.h> |
| 33 | |
Neels Hofmeyr | 37984bd | 2016-03-30 11:22:24 +0200 | [diff] [blame] | 34 | const struct value_string auth_action_names[] = { |
| 35 | #define AUTH_ACTION_STR(X) { X, #X } |
Neels Hofmeyr | f9b212f | 2016-03-30 11:22:27 +0200 | [diff] [blame] | 36 | AUTH_ACTION_STR(AUTH_ERROR), |
Neels Hofmeyr | 37984bd | 2016-03-30 11:22:24 +0200 | [diff] [blame] | 37 | AUTH_ACTION_STR(AUTH_NOT_AVAIL), |
| 38 | AUTH_ACTION_STR(AUTH_DO_AUTH_THEN_CIPH), |
| 39 | AUTH_ACTION_STR(AUTH_DO_CIPH), |
| 40 | AUTH_ACTION_STR(AUTH_DO_AUTH), |
| 41 | #undef AUTH_ACTION_STR |
Neels Hofmeyr | ecdfd6d | 2016-12-16 14:16:41 +0100 | [diff] [blame] | 42 | { 0, NULL } |
Neels Hofmeyr | 37984bd | 2016-03-30 11:22:24 +0200 | [diff] [blame] | 43 | }; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 44 | |
| 45 | static int |
Sylvain Munaut | e824d9c | 2010-06-11 00:19:42 +0200 | [diff] [blame] | 46 | _use_xor(struct gsm_auth_info *ainfo, struct gsm_auth_tuple *atuple) |
| 47 | { |
| 48 | int i, l = ainfo->a3a8_ki_len; |
| 49 | |
| 50 | if ((l > A38_XOR_MAX_KEY_LEN) || (l < A38_XOR_MIN_KEY_LEN)) { |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 51 | LOGP(DMM, LOGL_ERROR, "Invalid XOR key (len=%d) %s\n", |
Sylvain Munaut | e824d9c | 2010-06-11 00:19:42 +0200 | [diff] [blame] | 52 | ainfo->a3a8_ki_len, |
Pablo Neira Ayuso | c0d17f2 | 2011-05-07 12:12:48 +0200 | [diff] [blame] | 53 | osmo_hexdump(ainfo->a3a8_ki, ainfo->a3a8_ki_len)); |
Sylvain Munaut | e824d9c | 2010-06-11 00:19:42 +0200 | [diff] [blame] | 54 | return -1; |
| 55 | } |
| 56 | |
| 57 | for (i=0; i<4; i++) |
Harald Welte | 121e9a4 | 2016-04-20 13:13:19 +0200 | [diff] [blame] | 58 | atuple->vec.sres[i] = atuple->vec.rand[i] ^ ainfo->a3a8_ki[i]; |
Sylvain Munaut | 0230b34 | 2010-09-21 19:03:09 +0200 | [diff] [blame] | 59 | for (i=4; i<12; i++) |
Harald Welte | 121e9a4 | 2016-04-20 13:13:19 +0200 | [diff] [blame] | 60 | atuple->vec.kc[i-4] = atuple->vec.rand[i] ^ ainfo->a3a8_ki[i]; |
Sylvain Munaut | e824d9c | 2010-06-11 00:19:42 +0200 | [diff] [blame] | 61 | |
| 62 | return 0; |
| 63 | } |
| 64 | |
| 65 | static int |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 66 | _use_comp128_v1(struct gsm_auth_info *ainfo, struct gsm_auth_tuple *atuple) |
| 67 | { |
| 68 | if (ainfo->a3a8_ki_len != A38_COMP128_KEY_LEN) { |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 69 | LOGP(DMM, LOGL_ERROR, "Invalid COMP128v1 key (len=%d) %s\n", |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 70 | ainfo->a3a8_ki_len, |
Pablo Neira Ayuso | c0d17f2 | 2011-05-07 12:12:48 +0200 | [diff] [blame] | 71 | osmo_hexdump(ainfo->a3a8_ki, ainfo->a3a8_ki_len)); |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 72 | return -1; |
| 73 | } |
| 74 | |
Harald Welte | 121e9a4 | 2016-04-20 13:13:19 +0200 | [diff] [blame] | 75 | comp128(ainfo->a3a8_ki, atuple->vec.rand, atuple->vec.sres, atuple->vec.kc); |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 76 | |
| 77 | return 0; |
| 78 | } |
| 79 | |
| 80 | /* Return values |
| 81 | * -1 -> Internal error |
| 82 | * 0 -> Not available |
| 83 | * 1 -> Tuple returned, need to do auth, then enable cipher |
| 84 | * 2 -> Tuple returned, need to enable cipher |
| 85 | */ |
| 86 | int auth_get_tuple_for_subscr(struct gsm_auth_tuple *atuple, |
| 87 | struct gsm_subscriber *subscr, int key_seq) |
| 88 | { |
| 89 | struct gsm_auth_info ainfo; |
Daniel Willmann | 62a63f5 | 2015-10-08 16:10:25 +0200 | [diff] [blame] | 90 | int rc; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 91 | |
| 92 | /* Get subscriber info (if any) */ |
| 93 | rc = db_get_authinfo_for_subscr(&ainfo, subscr); |
| 94 | if (rc < 0) { |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 95 | LOGP(DMM, LOGL_NOTICE, |
| 96 | "No retrievable Ki for subscriber, skipping auth\n"); |
Neels Hofmeyr | f9b212f | 2016-03-30 11:22:27 +0200 | [diff] [blame] | 97 | return rc == -ENOENT ? AUTH_NOT_AVAIL : AUTH_ERROR; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 98 | } |
| 99 | |
| 100 | /* If possible, re-use the last tuple and skip auth */ |
| 101 | rc = db_get_lastauthtuple_for_subscr(atuple, subscr); |
| 102 | if ((rc == 0) && |
Sylvain Munaut | cd8e810 | 2010-09-21 19:04:07 +0200 | [diff] [blame] | 103 | (key_seq != GSM_KEY_SEQ_INVAL) && |
Neels Hofmeyr | 0d929be | 2016-03-30 11:22:29 +0200 | [diff] [blame] | 104 | (key_seq == atuple->key_seq) && |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 105 | (atuple->use_count < 3)) |
| 106 | { |
| 107 | atuple->use_count++; |
| 108 | db_sync_lastauthtuple_for_subscr(atuple, subscr); |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 109 | DEBUGP(DMM, "Auth tuple use < 3, just doing ciphering\n"); |
Harald Welte | 86dda08 | 2010-12-23 18:07:49 +0100 | [diff] [blame] | 110 | return AUTH_DO_CIPH; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 111 | } |
| 112 | |
| 113 | /* Generate a new one */ |
Neels Hofmeyr | cf1302e | 2016-03-30 11:22:30 +0200 | [diff] [blame] | 114 | if (rc != 0) { |
| 115 | /* If db_get_lastauthtuple_for_subscr() returned nothing, make |
| 116 | * sure the atuple memory is initialized to zero and thus start |
| 117 | * off with key_seq = 0. */ |
| 118 | memset(atuple, 0, sizeof(*atuple)); |
| 119 | } else { |
| 120 | /* If db_get_lastauthtuple_for_subscr() returned a previous |
| 121 | * tuple, use the next key_seq. */ |
| 122 | atuple->key_seq = (atuple->key_seq + 1) % 7; |
| 123 | } |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 124 | atuple->use_count = 1; |
Daniel Willmann | 62a63f5 | 2015-10-08 16:10:25 +0200 | [diff] [blame] | 125 | |
Harald Welte | 121e9a4 | 2016-04-20 13:13:19 +0200 | [diff] [blame] | 126 | if (RAND_bytes(atuple->vec.rand, sizeof(atuple->vec.rand)) != 1) { |
Daniel Willmann | 62a63f5 | 2015-10-08 16:10:25 +0200 | [diff] [blame] | 127 | LOGP(DMM, LOGL_NOTICE, "RAND_bytes failed, can't generate new auth tuple\n"); |
Neels Hofmeyr | f9b212f | 2016-03-30 11:22:27 +0200 | [diff] [blame] | 128 | return AUTH_ERROR; |
Daniel Willmann | 62a63f5 | 2015-10-08 16:10:25 +0200 | [diff] [blame] | 129 | } |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 130 | |
| 131 | switch (ainfo.auth_algo) { |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 132 | case AUTH_ALGO_NONE: |
| 133 | DEBUGP(DMM, "No authentication for subscriber\n"); |
Neels Hofmeyr | 4e875ae | 2016-03-30 11:22:28 +0200 | [diff] [blame] | 134 | return AUTH_NOT_AVAIL; |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 135 | |
| 136 | case AUTH_ALGO_XOR: |
| 137 | if (_use_xor(&ainfo, atuple)) |
Neels Hofmeyr | 4e875ae | 2016-03-30 11:22:28 +0200 | [diff] [blame] | 138 | return AUTH_NOT_AVAIL; |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 139 | break; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 140 | |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 141 | case AUTH_ALGO_COMP128v1: |
| 142 | if (_use_comp128_v1(&ainfo, atuple)) |
Neels Hofmeyr | 4e875ae | 2016-03-30 11:22:28 +0200 | [diff] [blame] | 143 | return AUTH_NOT_AVAIL; |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 144 | break; |
| 145 | |
| 146 | default: |
| 147 | DEBUGP(DMM, "Unsupported auth type algo_id=%d\n", |
| 148 | ainfo.auth_algo); |
Neels Hofmeyr | 4e875ae | 2016-03-30 11:22:28 +0200 | [diff] [blame] | 149 | return AUTH_NOT_AVAIL; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 150 | } |
| 151 | |
| 152 | db_sync_lastauthtuple_for_subscr(atuple, subscr); |
| 153 | |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 154 | DEBUGP(DMM, "Need to do authentication and ciphering\n"); |
Neels Hofmeyr | d2fa7a5 | 2016-03-10 23:30:37 +0100 | [diff] [blame] | 155 | return AUTH_DO_AUTH_THEN_CIPH; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 156 | } |
| 157 | |