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 | |
| 34 | |
| 35 | static int |
Sylvain Munaut | e824d9c | 2010-06-11 00:19:42 +0200 | [diff] [blame] | 36 | _use_xor(struct gsm_auth_info *ainfo, struct gsm_auth_tuple *atuple) |
| 37 | { |
| 38 | int i, l = ainfo->a3a8_ki_len; |
| 39 | |
| 40 | 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] | 41 | LOGP(DMM, LOGL_ERROR, "Invalid XOR key (len=%d) %s\n", |
Sylvain Munaut | e824d9c | 2010-06-11 00:19:42 +0200 | [diff] [blame] | 42 | ainfo->a3a8_ki_len, |
Pablo Neira Ayuso | c0d17f2 | 2011-05-07 12:12:48 +0200 | [diff] [blame] | 43 | osmo_hexdump(ainfo->a3a8_ki, ainfo->a3a8_ki_len)); |
Sylvain Munaut | e824d9c | 2010-06-11 00:19:42 +0200 | [diff] [blame] | 44 | return -1; |
| 45 | } |
| 46 | |
| 47 | for (i=0; i<4; i++) |
| 48 | atuple->sres[i] = atuple->rand[i] ^ ainfo->a3a8_ki[i]; |
Sylvain Munaut | 0230b34 | 2010-09-21 19:03:09 +0200 | [diff] [blame] | 49 | for (i=4; i<12; i++) |
Sylvain Munaut | e824d9c | 2010-06-11 00:19:42 +0200 | [diff] [blame] | 50 | atuple->kc[i-4] = atuple->rand[i] ^ ainfo->a3a8_ki[i]; |
| 51 | |
| 52 | return 0; |
| 53 | } |
| 54 | |
| 55 | static int |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 56 | _use_comp128_v1(struct gsm_auth_info *ainfo, struct gsm_auth_tuple *atuple) |
| 57 | { |
| 58 | if (ainfo->a3a8_ki_len != A38_COMP128_KEY_LEN) { |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 59 | LOGP(DMM, LOGL_ERROR, "Invalid COMP128v1 key (len=%d) %s\n", |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 60 | ainfo->a3a8_ki_len, |
Pablo Neira Ayuso | c0d17f2 | 2011-05-07 12:12:48 +0200 | [diff] [blame] | 61 | osmo_hexdump(ainfo->a3a8_ki, ainfo->a3a8_ki_len)); |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 62 | return -1; |
| 63 | } |
| 64 | |
| 65 | comp128(ainfo->a3a8_ki, atuple->rand, atuple->sres, atuple->kc); |
| 66 | |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | /* Return values |
| 71 | * -1 -> Internal error |
| 72 | * 0 -> Not available |
| 73 | * 1 -> Tuple returned, need to do auth, then enable cipher |
| 74 | * 2 -> Tuple returned, need to enable cipher |
| 75 | */ |
| 76 | int auth_get_tuple_for_subscr(struct gsm_auth_tuple *atuple, |
| 77 | struct gsm_subscriber *subscr, int key_seq) |
| 78 | { |
| 79 | struct gsm_auth_info ainfo; |
Daniel Willmann | 62a63f5 | 2015-10-08 16:10:25 +0200 | [diff] [blame] | 80 | int rc; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 81 | |
| 82 | /* Get subscriber info (if any) */ |
| 83 | rc = db_get_authinfo_for_subscr(&ainfo, subscr); |
| 84 | if (rc < 0) { |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 85 | LOGP(DMM, LOGL_NOTICE, |
| 86 | "No retrievable Ki for subscriber, skipping auth\n"); |
Harald Welte | 86dda08 | 2010-12-23 18:07:49 +0100 | [diff] [blame] | 87 | return rc == -ENOENT ? AUTH_NOT_AVAIL : -1; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 88 | } |
| 89 | |
| 90 | /* If possible, re-use the last tuple and skip auth */ |
| 91 | rc = db_get_lastauthtuple_for_subscr(atuple, subscr); |
| 92 | if ((rc == 0) && |
Sylvain Munaut | cd8e810 | 2010-09-21 19:04:07 +0200 | [diff] [blame] | 93 | (key_seq != GSM_KEY_SEQ_INVAL) && |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 94 | (atuple->use_count < 3)) |
| 95 | { |
| 96 | atuple->use_count++; |
| 97 | db_sync_lastauthtuple_for_subscr(atuple, subscr); |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 98 | DEBUGP(DMM, "Auth tuple use < 3, just doing ciphering\n"); |
Harald Welte | 86dda08 | 2010-12-23 18:07:49 +0100 | [diff] [blame] | 99 | return AUTH_DO_CIPH; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 100 | } |
| 101 | |
| 102 | /* Generate a new one */ |
| 103 | atuple->use_count = 1; |
| 104 | atuple->key_seq = (atuple->key_seq + 1) % 7; |
Daniel Willmann | 62a63f5 | 2015-10-08 16:10:25 +0200 | [diff] [blame] | 105 | |
| 106 | if (RAND_bytes(atuple->rand, sizeof(atuple->rand)) != 1) { |
| 107 | LOGP(DMM, LOGL_NOTICE, "RAND_bytes failed, can't generate new auth tuple\n"); |
| 108 | return -1; |
| 109 | } |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 110 | |
| 111 | switch (ainfo.auth_algo) { |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 112 | case AUTH_ALGO_NONE: |
| 113 | DEBUGP(DMM, "No authentication for subscriber\n"); |
| 114 | return 0; |
| 115 | |
| 116 | case AUTH_ALGO_XOR: |
| 117 | if (_use_xor(&ainfo, atuple)) |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 118 | return 0; |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 119 | break; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 120 | |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 121 | case AUTH_ALGO_COMP128v1: |
| 122 | if (_use_comp128_v1(&ainfo, atuple)) |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 123 | return 0; |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 124 | break; |
| 125 | |
| 126 | default: |
| 127 | DEBUGP(DMM, "Unsupported auth type algo_id=%d\n", |
| 128 | ainfo.auth_algo); |
| 129 | return 0; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 130 | } |
| 131 | |
| 132 | db_sync_lastauthtuple_for_subscr(atuple, subscr); |
| 133 | |
Harald Welte | 082b01f | 2010-12-23 22:54:06 +0100 | [diff] [blame] | 134 | DEBUGP(DMM, "Need to do authentication and ciphering\n"); |
Harald Welte | 86dda08 | 2010-12-23 18:07:49 +0100 | [diff] [blame] | 135 | return AUTH_DO_AUTH_THAN_CIPH; |
Sylvain Munaut | 30a1538 | 2009-12-24 00:27:26 +0100 | [diff] [blame] | 136 | } |
| 137 | |