Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 1 | /* GPRS LLC cipher core infrastructure */ |
| 2 | |
| 3 | /* (C) 2010 by Harald Welte <laforge@gnumonks.org> |
| 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> |
| 25 | |
Pablo Neira Ayuso | 8341934 | 2011-03-22 16:36:13 +0100 | [diff] [blame] | 26 | #include <osmocom/core/utils.h> |
| 27 | #include <osmocom/core/linuxlist.h> |
| 28 | #include <osmocom/core/plugin.h> |
Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 29 | |
| 30 | #include <osmocom/crypt/gprs_cipher.h> |
| 31 | |
| 32 | static LLIST_HEAD(gprs_ciphers); |
| 33 | |
| 34 | static struct gprs_cipher_impl *selected_ciphers[_GPRS_ALGO_NUM]; |
| 35 | |
Max | b897c42 | 2016-06-28 14:03:21 +0200 | [diff] [blame] | 36 | const struct value_string gprs_cipher_names[] = { |
| 37 | { GPRS_ALGO_GEA0, "GEA0" }, |
| 38 | { GPRS_ALGO_GEA1, "GEA1" }, |
| 39 | { GPRS_ALGO_GEA2, "GEA2" }, |
| 40 | { GPRS_ALGO_GEA3, "GEA3" }, |
| 41 | { GPRS_ALGO_GEA4, "GEA4" }, |
| 42 | { 0, NULL }, |
| 43 | }; |
| 44 | |
Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 45 | /* register a cipher with the core */ |
| 46 | int gprs_cipher_register(struct gprs_cipher_impl *ciph) |
| 47 | { |
Harald Welte | 4876dcf | 2011-07-16 12:03:13 +0200 | [diff] [blame] | 48 | if (ciph->algo >= ARRAY_SIZE(selected_ciphers)) |
Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 49 | return -ERANGE; |
| 50 | |
| 51 | llist_add_tail(&ciph->list, &gprs_ciphers); |
| 52 | |
| 53 | /* check if we want to select this implementation over others */ |
| 54 | if (!selected_ciphers[ciph->algo] || |
| 55 | (selected_ciphers[ciph->algo]->priority > ciph->priority)) |
| 56 | selected_ciphers[ciph->algo] = ciph; |
| 57 | |
| 58 | return 0; |
| 59 | } |
| 60 | |
| 61 | /* load all available GPRS cipher plugins */ |
| 62 | int gprs_cipher_load(const char *path) |
| 63 | { |
| 64 | /* load all plugins available from path */ |
Max | bf990bb | 2016-04-21 14:46:30 +0200 | [diff] [blame] | 65 | if (path) |
| 66 | return osmo_plugin_load_all(path); |
| 67 | return 0; |
Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 68 | } |
| 69 | |
| 70 | /* function to be called by core code */ |
| 71 | int gprs_cipher_run(uint8_t *out, uint16_t len, enum gprs_ciph_algo algo, |
Max | bf990bb | 2016-04-21 14:46:30 +0200 | [diff] [blame] | 72 | uint8_t *kc, uint32_t iv, enum gprs_cipher_direction dir) |
Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 73 | { |
Harald Welte | 4876dcf | 2011-07-16 12:03:13 +0200 | [diff] [blame] | 74 | if (algo >= ARRAY_SIZE(selected_ciphers)) |
Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 75 | return -ERANGE; |
| 76 | |
| 77 | if (!selected_ciphers[algo]) |
| 78 | return -EINVAL; |
| 79 | |
| 80 | if (len > GSM0464_CIPH_MAX_BLOCK) |
| 81 | return -ERANGE; |
| 82 | |
| 83 | /* run the actual cipher from the plugin */ |
| 84 | return selected_ciphers[algo]->run(out, len, kc, iv, dir); |
| 85 | } |
| 86 | |
Max | bf990bb | 2016-04-21 14:46:30 +0200 | [diff] [blame] | 87 | /*! \brief Obtain key lenght for given GPRS cipher |
| 88 | * \param[in] algo Enum representive GPRS cipher |
| 89 | * \returns unsigned integer key length for supported algorithms, |
| 90 | * for GEA0 and unknown ciphers will return 0 |
| 91 | */ |
| 92 | unsigned gprs_cipher_key_length(enum gprs_ciph_algo algo) |
| 93 | { |
| 94 | switch (algo) { |
| 95 | case GPRS_ALGO_GEA0: return 0; |
| 96 | case GPRS_ALGO_GEA1: |
| 97 | case GPRS_ALGO_GEA2: |
| 98 | case GPRS_ALGO_GEA3: return 8; |
| 99 | case GPRS_ALGO_GEA4: return 16; |
| 100 | default: return 0; |
| 101 | } |
| 102 | } |
| 103 | |
Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 104 | int gprs_cipher_supported(enum gprs_ciph_algo algo) |
| 105 | { |
Harald Welte | 4876dcf | 2011-07-16 12:03:13 +0200 | [diff] [blame] | 106 | if (algo >= ARRAY_SIZE(selected_ciphers)) |
Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 107 | return -ERANGE; |
| 108 | |
| 109 | if (selected_ciphers[algo]) |
| 110 | return 1; |
| 111 | |
| 112 | return 0; |
| 113 | } |
Harald Welte | e335b91 | 2010-06-30 19:50:14 +0200 | [diff] [blame] | 114 | |
| 115 | /* GSM TS 04.64 / Section A.2.1 : Generation of 'input' */ |
| 116 | uint32_t gprs_cipher_gen_input_ui(uint32_t iov_ui, uint8_t sapi, uint32_t lfn, uint32_t oc) |
| 117 | { |
| 118 | uint32_t sx = ((1<<27) * sapi) + (1<<31); |
| 119 | |
| 120 | return (iov_ui ^ sx) + lfn + oc; |
| 121 | } |
| 122 | |
| 123 | /* GSM TS 04.64 / Section A.2.1 : Generation of 'input' */ |
| 124 | uint32_t gprs_cipher_gen_input_i(uint32_t iov_i, uint32_t lfn, uint32_t oc) |
| 125 | { |
| 126 | return iov_i + lfn + oc; |
| 127 | } |