Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 1 | /* Gb-proxy message patching */ |
| 2 | |
| 3 | /* (C) 2014 by On-Waves |
| 4 | * All Rights Reserved |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU Affero General Public License as published by |
| 8 | * the Free Software Foundation; either version 3 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU Affero General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Affero General Public License |
| 17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 18 | * |
| 19 | */ |
| 20 | |
| 21 | #include <openbsc/gb_proxy.h> |
| 22 | |
| 23 | #include <openbsc/gprs_utils.h> |
| 24 | #include <openbsc/gprs_gb_parse.h> |
| 25 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 26 | #include <openbsc/gsm_data.h> |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 27 | #include <openbsc/debug.h> |
| 28 | |
| 29 | #include <osmocom/gprs/protocol/gsm_08_18.h> |
| 30 | #include <osmocom/core/rate_ctr.h> |
Harald Welte | 586e681 | 2017-08-12 13:43:54 +0200 | [diff] [blame^] | 31 | #include <osmocom/gsm/apn.h> |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 32 | |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 33 | /* patch RA identifier in place */ |
| 34 | static void gbproxy_patch_raid(uint8_t *raid_enc, struct gbproxy_peer *peer, |
| 35 | int to_bss, const char *log_text) |
| 36 | { |
| 37 | struct gbproxy_patch_state *state = &peer->patch_state; |
| 38 | int old_mcc; |
| 39 | int old_mnc; |
| 40 | struct gprs_ra_id raid; |
Jacob Erlbeck | cba4c0c | 2014-09-15 14:38:37 +0200 | [diff] [blame] | 41 | enum gbproxy_peer_ctr counter = |
| 42 | to_bss ? |
| 43 | GBPROX_PEER_CTR_RAID_PATCHED_SGSN : |
| 44 | GBPROX_PEER_CTR_RAID_PATCHED_BSS; |
| 45 | |
| 46 | if (!state->local_mcc || !state->local_mnc) |
| 47 | return; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 48 | |
| 49 | gsm48_parse_ra(&raid, raid_enc); |
| 50 | |
| 51 | old_mcc = raid.mcc; |
| 52 | old_mnc = raid.mnc; |
| 53 | |
| 54 | if (!to_bss) { |
| 55 | /* BSS -> SGSN */ |
| 56 | if (state->local_mcc) |
| 57 | raid.mcc = peer->cfg->core_mcc; |
| 58 | |
| 59 | if (state->local_mnc) |
| 60 | raid.mnc = peer->cfg->core_mnc; |
| 61 | } else { |
| 62 | /* SGSN -> BSS */ |
| 63 | if (state->local_mcc) |
| 64 | raid.mcc = state->local_mcc; |
| 65 | |
| 66 | if (state->local_mnc) |
| 67 | raid.mnc = state->local_mnc; |
| 68 | } |
| 69 | |
Jacob Erlbeck | cba4c0c | 2014-09-15 14:38:37 +0200 | [diff] [blame] | 70 | LOGP(DGPRS, LOGL_DEBUG, |
| 71 | "Patching %s to %s: " |
| 72 | "%d-%d-%d-%d -> %d-%d-%d-%d\n", |
| 73 | log_text, |
| 74 | to_bss ? "BSS" : "SGSN", |
| 75 | old_mcc, old_mnc, raid.lac, raid.rac, |
| 76 | raid.mcc, raid.mnc, raid.lac, raid.rac); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 77 | |
Jacob Erlbeck | cba4c0c | 2014-09-15 14:38:37 +0200 | [diff] [blame] | 78 | gsm48_construct_ra(raid_enc, &raid); |
| 79 | rate_ctr_inc(&peer->ctrg->ctr[counter]); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 80 | } |
| 81 | |
| 82 | static void gbproxy_patch_apn_ie(struct msgb *msg, |
| 83 | uint8_t *apn_ie, size_t apn_ie_len, |
| 84 | struct gbproxy_peer *peer, |
| 85 | size_t *new_apn_ie_len, const char *log_text) |
| 86 | { |
| 87 | struct apn_ie_hdr { |
| 88 | uint8_t iei; |
| 89 | uint8_t apn_len; |
| 90 | uint8_t apn[0]; |
| 91 | } *hdr = (void *)apn_ie; |
| 92 | |
| 93 | size_t apn_len = hdr->apn_len; |
| 94 | uint8_t *apn = hdr->apn; |
| 95 | |
| 96 | OSMO_ASSERT(apn_ie_len == apn_len + sizeof(struct apn_ie_hdr)); |
| 97 | OSMO_ASSERT(apn_ie_len > 2 && apn_ie_len <= 102); |
| 98 | |
| 99 | if (peer->cfg->core_apn_size == 0) { |
| 100 | char str1[110]; |
| 101 | /* Remove the IE */ |
| 102 | LOGP(DGPRS, LOGL_DEBUG, |
| 103 | "Patching %s to SGSN: Removing APN '%s'\n", |
| 104 | log_text, |
Harald Welte | 586e681 | 2017-08-12 13:43:54 +0200 | [diff] [blame^] | 105 | osmo_apn_to_str(str1, apn, apn_len)); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 106 | |
| 107 | *new_apn_ie_len = 0; |
| 108 | gprs_msgb_resize_area(msg, apn_ie, apn_ie_len, 0); |
| 109 | } else { |
| 110 | /* Resize the IE */ |
| 111 | char str1[110]; |
| 112 | char str2[110]; |
| 113 | |
| 114 | OSMO_ASSERT(peer->cfg->core_apn_size <= 100); |
| 115 | |
| 116 | LOGP(DGPRS, LOGL_DEBUG, |
| 117 | "Patching %s to SGSN: " |
| 118 | "Replacing APN '%s' -> '%s'\n", |
| 119 | log_text, |
Harald Welte | 586e681 | 2017-08-12 13:43:54 +0200 | [diff] [blame^] | 120 | osmo_apn_to_str(str1, apn, apn_len), |
| 121 | osmo_apn_to_str(str2, peer->cfg->core_apn, |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 122 | peer->cfg->core_apn_size)); |
| 123 | |
| 124 | *new_apn_ie_len = peer->cfg->core_apn_size + 2; |
| 125 | gprs_msgb_resize_area(msg, apn, apn_len, peer->cfg->core_apn_size); |
| 126 | memcpy(apn, peer->cfg->core_apn, peer->cfg->core_apn_size); |
| 127 | hdr->apn_len = peer->cfg->core_apn_size; |
| 128 | } |
| 129 | |
| 130 | rate_ctr_inc(&peer->ctrg->ctr[GBPROX_PEER_CTR_APN_PATCHED]); |
| 131 | } |
| 132 | |
| 133 | static int gbproxy_patch_tlli(uint8_t *tlli_enc, |
| 134 | struct gbproxy_peer *peer, |
| 135 | uint32_t new_tlli, |
| 136 | int to_bss, const char *log_text) |
| 137 | { |
| 138 | uint32_t tlli_be; |
| 139 | uint32_t tlli; |
| 140 | enum gbproxy_peer_ctr counter = |
| 141 | to_bss ? |
| 142 | GBPROX_PEER_CTR_TLLI_PATCHED_SGSN : |
| 143 | GBPROX_PEER_CTR_TLLI_PATCHED_BSS; |
| 144 | |
| 145 | memcpy(&tlli_be, tlli_enc, sizeof(tlli_be)); |
| 146 | tlli = ntohl(tlli_be); |
| 147 | |
| 148 | if (tlli == new_tlli) |
| 149 | return 0; |
| 150 | |
| 151 | LOGP(DGPRS, LOGL_DEBUG, |
| 152 | "Patching %ss: " |
| 153 | "Replacing %08x -> %08x\n", |
| 154 | log_text, tlli, new_tlli); |
| 155 | |
| 156 | tlli_be = htonl(new_tlli); |
| 157 | memcpy(tlli_enc, &tlli_be, sizeof(tlli_be)); |
| 158 | |
| 159 | rate_ctr_inc(&peer->ctrg->ctr[counter]); |
| 160 | |
| 161 | return 1; |
| 162 | } |
| 163 | |
| 164 | static int gbproxy_patch_ptmsi(uint8_t *ptmsi_enc, |
| 165 | struct gbproxy_peer *peer, |
| 166 | uint32_t new_ptmsi, |
| 167 | int to_bss, const char *log_text) |
| 168 | { |
| 169 | uint32_t ptmsi_be; |
| 170 | uint32_t ptmsi; |
| 171 | enum gbproxy_peer_ctr counter = |
| 172 | to_bss ? |
| 173 | GBPROX_PEER_CTR_PTMSI_PATCHED_SGSN : |
| 174 | GBPROX_PEER_CTR_PTMSI_PATCHED_BSS; |
Jacob Erlbeck | 4938917 | 2014-10-02 16:14:47 +0200 | [diff] [blame] | 175 | memcpy(&ptmsi_be, ptmsi_enc, sizeof(ptmsi_be)); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 176 | ptmsi = ntohl(ptmsi_be); |
| 177 | |
| 178 | if (ptmsi == new_ptmsi) |
| 179 | return 0; |
| 180 | |
| 181 | LOGP(DGPRS, LOGL_DEBUG, |
| 182 | "Patching %ss: " |
| 183 | "Replacing %08x -> %08x\n", |
| 184 | log_text, ptmsi, new_ptmsi); |
| 185 | |
| 186 | ptmsi_be = htonl(new_ptmsi); |
Jacob Erlbeck | 4938917 | 2014-10-02 16:14:47 +0200 | [diff] [blame] | 187 | memcpy(ptmsi_enc, &ptmsi_be, sizeof(ptmsi_be)); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 188 | |
| 189 | rate_ctr_inc(&peer->ctrg->ctr[counter]); |
| 190 | |
| 191 | return 1; |
| 192 | } |
| 193 | |
| 194 | int gbproxy_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len, |
| 195 | struct gbproxy_peer *peer, |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 196 | struct gbproxy_link_info *link_info, int *len_change, |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 197 | struct gprs_gb_parse_context *parse_ctx) |
| 198 | { |
| 199 | struct gprs_llc_hdr_parsed *ghp = &parse_ctx->llc_hdr_parsed; |
| 200 | int have_patched = 0; |
| 201 | int fcs; |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 202 | struct gbproxy_config *cfg = peer->cfg; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 203 | |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 204 | if (parse_ctx->ptmsi_enc && link_info && |
Jacob Erlbeck | cba4c0c | 2014-09-15 14:38:37 +0200 | [diff] [blame] | 205 | !parse_ctx->old_raid_is_foreign && peer->cfg->patch_ptmsi) { |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 206 | uint32_t ptmsi; |
| 207 | if (parse_ctx->to_bss) |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 208 | ptmsi = link_info->tlli.ptmsi; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 209 | else |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 210 | ptmsi = link_info->sgsn_tlli.ptmsi; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 211 | |
| 212 | if (ptmsi != GSM_RESERVED_TMSI) { |
| 213 | if (gbproxy_patch_ptmsi(parse_ctx->ptmsi_enc, peer, |
| 214 | ptmsi, parse_ctx->to_bss, "P-TMSI")) |
| 215 | have_patched = 1; |
| 216 | } else { |
| 217 | /* TODO: invalidate old RAI if present (see below) */ |
| 218 | } |
| 219 | } |
| 220 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 221 | if (parse_ctx->new_ptmsi_enc && link_info && cfg->patch_ptmsi) { |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 222 | uint32_t ptmsi; |
| 223 | if (parse_ctx->to_bss) |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 224 | ptmsi = link_info->tlli.ptmsi; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 225 | else |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 226 | ptmsi = link_info->sgsn_tlli.ptmsi; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 227 | |
| 228 | OSMO_ASSERT(ptmsi); |
| 229 | if (gbproxy_patch_ptmsi(parse_ctx->new_ptmsi_enc, peer, |
| 230 | ptmsi, parse_ctx->to_bss, "new P-TMSI")) |
| 231 | have_patched = 1; |
| 232 | } |
| 233 | |
| 234 | if (parse_ctx->raid_enc) { |
| 235 | gbproxy_patch_raid(parse_ctx->raid_enc, peer, parse_ctx->to_bss, |
| 236 | parse_ctx->llc_msg_name); |
| 237 | have_patched = 1; |
| 238 | } |
| 239 | |
Jacob Erlbeck | 948c07f | 2014-09-11 15:22:18 +0200 | [diff] [blame] | 240 | if (parse_ctx->old_raid_enc && !parse_ctx->old_raid_is_foreign) { |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 241 | /* TODO: Patch to invalid if P-TMSI unknown. */ |
| 242 | gbproxy_patch_raid(parse_ctx->old_raid_enc, peer, parse_ctx->to_bss, |
| 243 | parse_ctx->llc_msg_name); |
| 244 | have_patched = 1; |
| 245 | } |
| 246 | |
| 247 | if (parse_ctx->apn_ie && |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 248 | cfg->core_apn && |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 249 | !parse_ctx->to_bss && |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 250 | gbproxy_imsi_matches(cfg, GBPROX_MATCH_PATCHING, link_info) && |
| 251 | cfg->core_apn) { |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 252 | size_t new_len; |
| 253 | gbproxy_patch_apn_ie(msg, |
| 254 | parse_ctx->apn_ie, parse_ctx->apn_ie_len, |
| 255 | peer, &new_len, parse_ctx->llc_msg_name); |
| 256 | *len_change += (int)new_len - (int)parse_ctx->apn_ie_len; |
| 257 | |
| 258 | have_patched = 1; |
| 259 | } |
| 260 | |
| 261 | if (have_patched) { |
| 262 | llc_len += *len_change; |
| 263 | ghp->crc_length += *len_change; |
| 264 | |
| 265 | /* Fix FCS */ |
| 266 | fcs = gprs_llc_fcs(llc, ghp->crc_length); |
| 267 | LOGP(DLLC, LOGL_DEBUG, "Updated LLC message, CRC: %06x -> %06x\n", |
| 268 | ghp->fcs, fcs); |
| 269 | |
| 270 | llc[llc_len - 3] = fcs & 0xff; |
| 271 | llc[llc_len - 2] = (fcs >> 8) & 0xff; |
| 272 | llc[llc_len - 1] = (fcs >> 16) & 0xff; |
| 273 | } |
| 274 | |
| 275 | return have_patched; |
| 276 | } |
| 277 | |
| 278 | /* patch BSSGP message to use core_mcc/mnc on the SGSN side */ |
| 279 | void gbproxy_patch_bssgp(struct msgb *msg, uint8_t *bssgp, size_t bssgp_len, |
| 280 | struct gbproxy_peer *peer, |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 281 | struct gbproxy_link_info *link_info, int *len_change, |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 282 | struct gprs_gb_parse_context *parse_ctx) |
| 283 | { |
| 284 | const char *err_info = NULL; |
| 285 | int err_ctr = -1; |
| 286 | |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 287 | if (parse_ctx->bssgp_raid_enc) |
| 288 | gbproxy_patch_raid(parse_ctx->bssgp_raid_enc, peer, |
| 289 | parse_ctx->to_bss, "BSSGP"); |
| 290 | |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 291 | if (parse_ctx->need_decryption && |
Jacob Erlbeck | 1abfdc2 | 2014-09-04 11:42:08 +0200 | [diff] [blame] | 292 | (peer->cfg->patch_ptmsi || peer->cfg->core_apn)) { |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 293 | /* Patching LLC messages has been requested |
| 294 | * explicitly, but the message (including the |
| 295 | * type) is encrypted, so we possibly fail to |
| 296 | * patch the LLC part of the message. */ |
| 297 | err_ctr = GBPROX_PEER_CTR_PATCH_CRYPT_ERR; |
| 298 | err_info = "GMM message is encrypted"; |
| 299 | goto patch_error; |
| 300 | } |
| 301 | |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 302 | if (!link_info && parse_ctx->tlli_enc && parse_ctx->to_bss) { |
Jacob Erlbeck | 37fda77 | 2014-09-05 10:22:27 +0200 | [diff] [blame] | 303 | /* Happens with unknown (not cached) TLLI coming from |
| 304 | * the SGSN */ |
| 305 | /* TODO: What shall be done with the message in this case? */ |
| 306 | err_ctr = GBPROX_PEER_CTR_TLLI_UNKNOWN; |
| 307 | err_info = "TLLI sent by the SGSN is unknown"; |
| 308 | goto patch_error; |
| 309 | } |
| 310 | |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 311 | if (!link_info) |
Jacob Erlbeck | ecbd56c | 2014-08-26 10:01:57 +0200 | [diff] [blame] | 312 | return; |
| 313 | |
Jacob Erlbeck | cba4c0c | 2014-09-15 14:38:37 +0200 | [diff] [blame] | 314 | if (parse_ctx->tlli_enc && peer->cfg->patch_ptmsi) { |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 315 | uint32_t tlli = gbproxy_map_tlli(parse_ctx->tlli, |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 316 | link_info, parse_ctx->to_bss); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 317 | |
| 318 | if (tlli) { |
| 319 | gbproxy_patch_tlli(parse_ctx->tlli_enc, peer, tlli, |
| 320 | parse_ctx->to_bss, "TLLI"); |
| 321 | parse_ctx->tlli = tlli; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 322 | } else { |
| 323 | /* Internal error */ |
| 324 | err_ctr = GBPROX_PEER_CTR_PATCH_ERR; |
| 325 | err_info = "Replacement TLLI is 0"; |
| 326 | goto patch_error; |
| 327 | } |
| 328 | } |
| 329 | |
Jacob Erlbeck | c37ef6c | 2014-09-30 13:49:43 +0200 | [diff] [blame] | 330 | if (parse_ctx->bssgp_ptmsi_enc && peer->cfg->patch_ptmsi) { |
| 331 | uint32_t ptmsi; |
| 332 | if (parse_ctx->to_bss) |
| 333 | ptmsi = link_info->tlli.ptmsi; |
| 334 | else |
| 335 | ptmsi = link_info->sgsn_tlli.ptmsi; |
| 336 | |
| 337 | if (ptmsi != GSM_RESERVED_TMSI) |
| 338 | gbproxy_patch_ptmsi( |
| 339 | parse_ctx->bssgp_ptmsi_enc, peer, |
| 340 | ptmsi, parse_ctx->to_bss, "BSSGP P-TMSI"); |
| 341 | } |
| 342 | |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 343 | if (parse_ctx->llc) { |
| 344 | uint8_t *llc = parse_ctx->llc; |
| 345 | size_t llc_len = parse_ctx->llc_len; |
| 346 | int llc_len_change = 0; |
| 347 | |
Jacob Erlbeck | 91d2f8a | 2014-09-19 15:07:27 +0200 | [diff] [blame] | 348 | gbproxy_patch_llc(msg, llc, llc_len, peer, link_info, |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 349 | &llc_len_change, parse_ctx); |
| 350 | /* Note that the APN might have been resized here, but no |
| 351 | * pointer int the parse_ctx will refer to an adress after the |
| 352 | * APN. So it's possible to patch first and do the TLLI |
| 353 | * handling afterwards. */ |
| 354 | |
| 355 | if (llc_len_change) { |
| 356 | llc_len += llc_len_change; |
| 357 | |
| 358 | /* Fix LLC IE len */ |
| 359 | /* TODO: This is a kludge, but the a pointer to the |
| 360 | * start of the IE is not available here */ |
| 361 | if (llc[-2] == BSSGP_IE_LLC_PDU && llc[-1] & 0x80) { |
| 362 | /* most probably a one byte length */ |
| 363 | if (llc_len > 127) { |
| 364 | err_info = "Cannot increase size"; |
| 365 | err_ctr = GBPROX_PEER_CTR_PATCH_ERR; |
| 366 | goto patch_error; |
| 367 | } |
| 368 | llc[-1] = llc_len | 0x80; |
| 369 | } else { |
| 370 | llc[-2] = (llc_len >> 8) & 0x7f; |
| 371 | llc[-1] = llc_len & 0xff; |
| 372 | } |
| 373 | *len_change += llc_len_change; |
| 374 | } |
| 375 | /* Note that the tp struct might contain invalid pointers here |
| 376 | * if the LLC field has changed its size */ |
| 377 | parse_ctx->llc_len = llc_len; |
| 378 | } |
| 379 | return; |
| 380 | |
| 381 | patch_error: |
| 382 | OSMO_ASSERT(err_ctr >= 0); |
| 383 | rate_ctr_inc(&peer->ctrg->ctr[err_ctr]); |
| 384 | LOGP(DGPRS, LOGL_ERROR, |
| 385 | "NSEI=%u(%s) failed to patch BSSGP message as requested: %s.\n", |
| 386 | msgb_nsei(msg), parse_ctx->to_bss ? "SGSN" : "BSS", |
| 387 | err_info); |
| 388 | } |
| 389 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 390 | void gbproxy_clear_patch_filter(struct gbproxy_match *match) |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 391 | { |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 392 | if (match->enable) { |
| 393 | regfree(&match->re_comp); |
| 394 | match->enable = 0; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 395 | } |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 396 | talloc_free(match->re_str); |
| 397 | match->re_str = NULL; |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 398 | } |
| 399 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 400 | int gbproxy_set_patch_filter(struct gbproxy_match *match, const char *filter, |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 401 | const char **err_msg) |
| 402 | { |
| 403 | static char err_buf[300]; |
| 404 | int rc; |
| 405 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 406 | gbproxy_clear_patch_filter(match); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 407 | |
| 408 | if (!filter) |
| 409 | return 0; |
| 410 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 411 | rc = regcomp(&match->re_comp, filter, |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 412 | REG_EXTENDED | REG_NOSUB | REG_ICASE); |
| 413 | |
| 414 | if (rc == 0) { |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 415 | match->enable = 1; |
| 416 | match->re_str = talloc_strdup(tall_bsc_ctx, filter); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 417 | return 0; |
| 418 | } |
| 419 | |
| 420 | if (err_msg) { |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 421 | regerror(rc, &match->re_comp, |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 422 | err_buf, sizeof(err_buf)); |
| 423 | *err_msg = err_buf; |
| 424 | } |
| 425 | |
| 426 | return -1; |
| 427 | } |
| 428 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 429 | int gbproxy_check_imsi(struct gbproxy_match *match, |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 430 | const uint8_t *imsi, size_t imsi_len) |
| 431 | { |
| 432 | char mi_buf[200]; |
| 433 | int rc; |
| 434 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 435 | if (!match->enable) |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 436 | return 1; |
| 437 | |
| 438 | rc = gprs_is_mi_imsi(imsi, imsi_len); |
| 439 | if (rc > 0) |
| 440 | rc = gsm48_mi_to_string(mi_buf, sizeof(mi_buf), imsi, imsi_len); |
| 441 | if (rc <= 0) { |
| 442 | LOGP(DGPRS, LOGL_NOTICE, "Invalid IMSI %s\n", |
| 443 | osmo_hexdump(imsi, imsi_len)); |
| 444 | return -1; |
| 445 | } |
| 446 | |
| 447 | LOGP(DGPRS, LOGL_DEBUG, "Checking IMSI '%s' (%d)\n", mi_buf, rc); |
| 448 | |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 449 | rc = regexec(&match->re_comp, mi_buf, 0, NULL, 0); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 450 | if (rc == REG_NOMATCH) { |
| 451 | LOGP(DGPRS, LOGL_INFO, |
| 452 | "IMSI '%s' doesn't match pattern '%s'\n", |
Jacob Erlbeck | 9a83d7a | 2014-09-25 11:17:31 +0200 | [diff] [blame] | 453 | mi_buf, match->re_str); |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 454 | return 0; |
| 455 | } |
| 456 | |
| 457 | return 1; |
| 458 | } |
| 459 | |