Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 1 | /* GSM/GPRS/3G authentication core infrastructure */ |
| 2 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 3 | /* (C) 2010-2012 by Harald Welte <laforge@gnumonks.org> |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 4 | * |
| 5 | * All Rights Reserved |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License along |
| 18 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 19 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <errno.h> |
| 24 | #include <stdint.h> |
Harald Welte | d318e61 | 2011-12-07 12:16:27 +0100 | [diff] [blame] | 25 | #include <string.h> |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 26 | |
| 27 | #include <osmocom/core/utils.h> |
| 28 | #include <osmocom/core/linuxlist.h> |
| 29 | #include <osmocom/core/plugin.h> |
| 30 | |
| 31 | #include <osmocom/crypt/auth.h> |
| 32 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 33 | /*! \addtogroup auth |
| 34 | * @{ |
Harald Welte | 96e2a00 | 2017-06-12 21:44:18 +0200 | [diff] [blame] | 35 | * \brief GSM/GPRS/3G authentication core infrastructure |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 36 | */ |
| 37 | |
Harald Welte | 96e2a00 | 2017-06-12 21:44:18 +0200 | [diff] [blame] | 38 | /* \file auth_core.c */ |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 39 | |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 40 | static LLIST_HEAD(osmo_auths); |
| 41 | |
| 42 | static struct osmo_auth_impl *selected_auths[_OSMO_AUTH_ALG_NUM]; |
| 43 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 44 | /*! \brief Register an authentication algorithm implementation with the core |
| 45 | * \param[in] impl Structure describing implementation and it's callbacks |
Neels Hofmeyr | c7bf8d0 | 2016-05-08 22:23:40 +0200 | [diff] [blame] | 46 | * \returns 0 on success, or a negative error code on failure |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 47 | * |
| 48 | * This function is called by an authentication implementation plugin to |
| 49 | * register itself with the authentication core. |
| 50 | */ |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 51 | int osmo_auth_register(struct osmo_auth_impl *impl) |
| 52 | { |
| 53 | if (impl->algo >= ARRAY_SIZE(selected_auths)) |
| 54 | return -ERANGE; |
| 55 | |
| 56 | llist_add_tail(&impl->list, &osmo_auths); |
| 57 | |
| 58 | /* check if we want to select this implementation over others */ |
| 59 | if (!selected_auths[impl->algo] || |
| 60 | (selected_auths[impl->algo]->priority > impl->priority)) |
| 61 | selected_auths[impl->algo] = impl; |
| 62 | |
| 63 | return 0; |
| 64 | } |
| 65 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 66 | /*! \brief Load all available authentication plugins from the given path |
| 67 | * \param[in] path Path name of the directory containing the plugins |
Neels Hofmeyr | c7bf8d0 | 2016-05-08 22:23:40 +0200 | [diff] [blame] | 68 | * \returns number of plugins loaded in case of success, negative in case of error |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 69 | * |
| 70 | * This function will load all plugins contained in the specified path. |
| 71 | */ |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 72 | int osmo_auth_load(const char *path) |
| 73 | { |
| 74 | /* load all plugins available from path */ |
| 75 | return osmo_plugin_load_all(path); |
| 76 | } |
| 77 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 78 | /*! \brief Determine if a given authentication algorithm is supported |
| 79 | * \param[in] algo Algorithm which should be checked |
Neels Hofmeyr | c7bf8d0 | 2016-05-08 22:23:40 +0200 | [diff] [blame] | 80 | * \returns 1 if algo is supported, 0 if not, negative error on failure |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 81 | * |
| 82 | * This function is used by an application to determine at runtime if a |
| 83 | * given authentication algorithm is supported or not. |
| 84 | */ |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 85 | int osmo_auth_supported(enum osmo_auth_algo algo) |
| 86 | { |
| 87 | if (algo >= ARRAY_SIZE(selected_auths)) |
| 88 | return -ERANGE; |
| 89 | |
| 90 | if (selected_auths[algo]) |
| 91 | return 1; |
| 92 | |
| 93 | return 0; |
| 94 | } |
| 95 | |
Harald Welte | cd9cb90 | 2016-04-20 10:39:00 +0200 | [diff] [blame] | 96 | /* C5 function to derive UMTS IK from GSM Kc */ |
| 97 | static inline void c5_function(uint8_t *ik, const uint8_t *kc) |
| 98 | { |
| 99 | unsigned int i; |
| 100 | |
| 101 | for (i = 0; i < 4; i++) |
| 102 | ik[i] = kc[i] ^ kc[i+4]; |
| 103 | memcpy(ik+4, kc, 8); |
| 104 | for (i = 12; i < 16; i++) |
| 105 | ik[i] = ik[i-12]; |
| 106 | } |
| 107 | |
| 108 | /* C4 function to derive UMTS CK from GSM Kc */ |
Max | ceae123 | 2016-06-27 18:12:49 +0200 | [diff] [blame] | 109 | void osmo_c4(uint8_t *ck, const uint8_t *kc) |
Harald Welte | cd9cb90 | 2016-04-20 10:39:00 +0200 | [diff] [blame] | 110 | { |
| 111 | memcpy(ck, kc, 8); |
| 112 | memcpy(ck+8, kc, 8); |
| 113 | } |
| 114 | |
| 115 | /*! \brief Generate 3G CK + IK from 2G authentication vector |
| 116 | * \param vec Authentication Vector to be modified |
Neels Hofmeyr | c7bf8d0 | 2016-05-08 22:23:40 +0200 | [diff] [blame] | 117 | * \returns 1 if the vector was changed, 0 otherwise |
Harald Welte | cd9cb90 | 2016-04-20 10:39:00 +0200 | [diff] [blame] | 118 | * |
| 119 | * This function performs the C5 and C4 functions to derive the UMTS key |
| 120 | * material from the GSM key material in the supplied vector, _if_ the input |
Neels Hofmeyr | c7bf8d0 | 2016-05-08 22:23:40 +0200 | [diff] [blame] | 121 | * vector doesn't yet have UMTS authentication capability. |
| 122 | */ |
Harald Welte | cd9cb90 | 2016-04-20 10:39:00 +0200 | [diff] [blame] | 123 | int osmo_auth_3g_from_2g(struct osmo_auth_vector *vec) |
| 124 | { |
| 125 | if ((vec->auth_types & OSMO_AUTH_TYPE_GSM) && |
| 126 | !(vec->auth_types & OSMO_AUTH_TYPE_UMTS)) { |
| 127 | c5_function(vec->ik, vec->kc); |
Max | ceae123 | 2016-06-27 18:12:49 +0200 | [diff] [blame] | 128 | osmo_c4(vec->ck, vec->kc); |
Harald Welte | cd9cb90 | 2016-04-20 10:39:00 +0200 | [diff] [blame] | 129 | /* We cannot actually set OSMO_AUTH_TYPE_UMTS as we have no |
| 130 | * AUTN and no RES, and thus can only perform GSM |
| 131 | * authentication with this tuple. |
Neels Hofmeyr | c7bf8d0 | 2016-05-08 22:23:40 +0200 | [diff] [blame] | 132 | */ |
Harald Welte | cd9cb90 | 2016-04-20 10:39:00 +0200 | [diff] [blame] | 133 | return 1; |
| 134 | } |
| 135 | |
| 136 | return 0; |
| 137 | } |
| 138 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 139 | /*! \brief Generate authentication vector |
| 140 | * \param[out] vec Generated authentication vector |
| 141 | * \param[in] aud Subscriber-specific key material |
Katerina Barone-Adesi | c28c6a0 | 2013-02-15 13:27:59 +0100 | [diff] [blame] | 142 | * \param[in] _rand Random challenge to be used |
Neels Hofmeyr | c7bf8d0 | 2016-05-08 22:23:40 +0200 | [diff] [blame] | 143 | * \returns 0 on success, negative error on failure |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 144 | * |
| 145 | * This function performs the core cryptographic function of the AUC, |
| 146 | * computing authentication triples/quintuples based on the permanent |
| 147 | * subscriber data and a random value. The result is what is forwarded |
| 148 | * by the AUC via HLR and VLR to the MSC which will then be able to |
| 149 | * invoke authentication with the MS |
| 150 | */ |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 151 | int osmo_auth_gen_vec(struct osmo_auth_vector *vec, |
| 152 | struct osmo_sub_auth_data *aud, |
| 153 | const uint8_t *_rand) |
| 154 | { |
Harald Welte | 781bd5d | 2011-12-06 22:23:52 +0100 | [diff] [blame] | 155 | struct osmo_auth_impl *impl = selected_auths[aud->algo]; |
Harald Welte | 4afdd5d | 2011-12-07 02:38:18 +0100 | [diff] [blame] | 156 | int rc; |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 157 | |
| 158 | if (!impl) |
| 159 | return -ENOENT; |
| 160 | |
Harald Welte | 4afdd5d | 2011-12-07 02:38:18 +0100 | [diff] [blame] | 161 | rc = impl->gen_vec(vec, aud, _rand); |
| 162 | if (rc < 0) |
| 163 | return rc; |
| 164 | |
| 165 | memcpy(vec->rand, _rand, sizeof(vec->rand)); |
| 166 | |
| 167 | return 0; |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 168 | } |
| 169 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 170 | /*! \brief Generate authentication vector and re-sync sequence |
| 171 | * \param[out] vec Generated authentication vector |
| 172 | * \param[in] aud Subscriber-specific key material |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 173 | * \param[in] auts AUTS value sent by the SIM/MS |
Neels Hofmeyr | 03ab9a6 | 2017-02-03 05:00:24 +0100 | [diff] [blame] | 174 | * \param[in] rand_auts RAND value sent by the SIM/MS |
Katerina Barone-Adesi | c28c6a0 | 2013-02-15 13:27:59 +0100 | [diff] [blame] | 175 | * \param[in] _rand Random challenge to be used to generate vector |
Neels Hofmeyr | c7bf8d0 | 2016-05-08 22:23:40 +0200 | [diff] [blame] | 176 | * \returns 0 on success, negative error on failure |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 177 | * |
| 178 | * This function performs a special variant of the core cryptographic |
| 179 | * function of the AUC: computing authentication triples/quintuples |
| 180 | * based on the permanent subscriber data, a random value as well as the |
| 181 | * AUTS and RAND values returned by the SIM/MS. This special variant is |
| 182 | * needed if the sequence numbers between MS and AUC have for some |
Thorsten Alteholz | a81055d | 2017-03-02 22:13:48 +0100 | [diff] [blame] | 183 | * reason become different. |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 184 | */ |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 185 | int osmo_auth_gen_vec_auts(struct osmo_auth_vector *vec, |
| 186 | struct osmo_sub_auth_data *aud, |
Neels Hofmeyr | 03ab9a6 | 2017-02-03 05:00:24 +0100 | [diff] [blame] | 187 | const uint8_t *auts, const uint8_t *rand_auts, |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 188 | const uint8_t *_rand) |
| 189 | { |
Harald Welte | 781bd5d | 2011-12-06 22:23:52 +0100 | [diff] [blame] | 190 | struct osmo_auth_impl *impl = selected_auths[aud->algo]; |
Neels Hofmeyr | 3b8cb39 | 2017-02-21 19:54:36 +0100 | [diff] [blame] | 191 | int rc; |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 192 | |
| 193 | if (!impl || !impl->gen_vec_auts) |
| 194 | return -ENOENT; |
| 195 | |
Neels Hofmeyr | 3b8cb39 | 2017-02-21 19:54:36 +0100 | [diff] [blame] | 196 | rc = impl->gen_vec_auts(vec, aud, auts, rand_auts, _rand); |
| 197 | if (rc < 0) |
| 198 | return rc; |
| 199 | |
| 200 | memcpy(vec->rand, _rand, sizeof(vec->rand)); |
| 201 | |
| 202 | return 0; |
Harald Welte | d82e0eb | 2011-12-06 21:53:42 +0100 | [diff] [blame] | 203 | } |
Harald Welte | a5ab162 | 2011-12-07 02:33:11 +0100 | [diff] [blame] | 204 | |
Harald Welte | 1c72bfb | 2012-04-04 22:05:24 +0200 | [diff] [blame] | 205 | static const struct value_string auth_alg_vals[] = { |
Harald Welte | a5ab162 | 2011-12-07 02:33:11 +0100 | [diff] [blame] | 206 | { OSMO_AUTH_ALG_NONE, "None" }, |
| 207 | { OSMO_AUTH_ALG_COMP128v1, "COMP128v1" }, |
| 208 | { OSMO_AUTH_ALG_COMP128v2, "COMP128v2" }, |
| 209 | { OSMO_AUTH_ALG_COMP128v3, "COMP128v3" }, |
| 210 | { OSMO_AUTH_ALG_XOR, "XOR" }, |
| 211 | { OSMO_AUTH_ALG_MILENAGE, "MILENAGE" }, |
| 212 | { 0, NULL } |
| 213 | }; |
| 214 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 215 | /*! \brief Get human-readable name of authentication algorithm */ |
Harald Welte | a5ab162 | 2011-12-07 02:33:11 +0100 | [diff] [blame] | 216 | const char *osmo_auth_alg_name(enum osmo_auth_algo alg) |
| 217 | { |
| 218 | return get_value_string(auth_alg_vals, alg); |
| 219 | } |
| 220 | |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 221 | /*! \brief Parse human-readable name of authentication algorithm */ |
Harald Welte | a5ab162 | 2011-12-07 02:33:11 +0100 | [diff] [blame] | 222 | enum osmo_auth_algo osmo_auth_alg_parse(const char *name) |
| 223 | { |
| 224 | return get_string_value(auth_alg_vals, name); |
| 225 | } |
Harald Welte | 007a71e | 2012-07-18 19:47:56 +0200 | [diff] [blame] | 226 | |
| 227 | /*! @} */ |