diff options
author | Holger Hans Peter Freyther <holger@moiji-mobile.com> | 2015-04-04 18:42:46 +0200 |
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committer | Holger Hans Peter Freyther <holger@moiji-mobile.com> | 2015-05-03 21:42:27 +0200 |
commit | 4247cead2b77b2ad8ae2a6c1b48a450309185bb3 (patch) | |
tree | c1eabe06e86ee7bf958a5f6aeeaec490ef543cd1 /openbsc/src/osmo-bsc_nat/bsc_nat_filter.c | |
parent | 38159428d2b1e95a2c6fa91775f7b3678aef2f1f (diff) |
filter: Move the gsm 04.08 filter to a common place
For customer requirements we want to be able to do
filtering on the BSC as well. The same messages need
to be scanned and the same access-lists will be looked
at. In the future we might even split traffic based
on the IMSI. Begin with moving the code to a new top
level directory and then renaming and removing the
nat dependency.
Diffstat (limited to 'openbsc/src/osmo-bsc_nat/bsc_nat_filter.c')
-rw-r--r-- | openbsc/src/osmo-bsc_nat/bsc_nat_filter.c | 443 |
1 files changed, 0 insertions, 443 deletions
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c deleted file mode 100644 index 64f6d7347..000000000 --- a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c +++ /dev/null @@ -1,443 +0,0 @@ -/* - * Access filtering - */ -/* - * (C) 2010-2012 by Holger Hans Peter Freyther <zecke@selfish.org> - * (C) 2010-2012 by On-Waves - * All Rights Reserved - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU Affero General Public License as published by - * the Free Software Foundation; either version 3 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU Affero General Public License for more details. - * - * You should have received a copy of the GNU Affero General Public License - * along with this program. If not, see <http://www.gnu.org/licenses/>. - * - */ - -#include <openbsc/bsc_nat.h> -#include <openbsc/bsc_nat_sccp.h> -#include <openbsc/bsc_msc.h> -#include <openbsc/gsm_data.h> -#include <openbsc/debug.h> -#include <openbsc/ipaccess.h> - -#include <osmocom/core/linuxlist.h> -#include <osmocom/core/talloc.h> -#include <osmocom/gsm/gsm0808.h> - -#include <osmocom/gsm/protocol/gsm_08_08.h> -#include <osmocom/gsm/protocol/gsm_04_11.h> - -#include <osmocom/sccp/sccp.h> - -int bsc_nat_barr_find(struct rb_root *root, const char *imsi, int *cm, int *lu) -{ - struct bsc_nat_barr_entry *n; - n = rb_entry(root->rb_node, struct bsc_nat_barr_entry, node); - - while (n) { - int rc = strcmp(imsi, n->imsi); - if (rc == 0) { - *cm = n->cm_reject_cause; - *lu = n->lu_reject_cause; - return 1; - } - - n = rb_entry( - (rc < 0) ? n->node.rb_left : n->node.rb_right, - struct bsc_nat_barr_entry, node); - }; - - return 0; -} - -static int insert_barr_node(struct bsc_nat_barr_entry *entry, struct rb_root *root) -{ - struct rb_node **new = &root->rb_node, *parent = NULL; - - while (*new) { - int rc; - struct bsc_nat_barr_entry *this; - this = rb_entry(*new, struct bsc_nat_barr_entry, node); - parent = *new; - - rc = strcmp(entry->imsi, this->imsi); - if (rc < 0) - new = &((*new)->rb_left); - else if (rc > 0) - new = &((*new)->rb_right); - else { - LOGP(DNAT, LOGL_ERROR, - "Duplicate entry for IMSI(%s)\n", entry->imsi); - talloc_free(entry); - return -1; - } - } - - rb_link_node(&entry->node, parent, new); - rb_insert_color(&entry->node, root); - return 0; -} - -int bsc_nat_barr_adapt(void *ctx, struct rb_root *root, - const struct osmo_config_list *list) -{ - struct osmo_config_entry *cfg_entry; - int err = 0; - - /* free the old data */ - while (!RB_EMPTY_ROOT(root)) { - struct rb_node *node = rb_first(root); - rb_erase(node, root); - talloc_free(node); - } - - if (!list) - return 0; - - /* now adapt the new list */ - llist_for_each_entry(cfg_entry, &list->entry, list) { - struct bsc_nat_barr_entry *entry; - entry = talloc_zero(ctx, struct bsc_nat_barr_entry); - if (!entry) { - LOGP(DNAT, LOGL_ERROR, - "Allocation of the barr entry failed.\n"); - continue; - } - - entry->imsi = talloc_strdup(entry, cfg_entry->mcc); - entry->cm_reject_cause = atoi(cfg_entry->mnc); - entry->lu_reject_cause = atoi(cfg_entry->option); - err |= insert_barr_node(entry, root); - } - - return err; -} - - -static int lst_check_deny(struct bsc_nat_acc_lst *lst, const char *mi_string, - int *cm_cause, int *lu_cause) -{ - struct bsc_nat_acc_lst_entry *entry; - - llist_for_each_entry(entry, &lst->fltr_list, list) { - if (!entry->imsi_deny) - continue; - if (regexec(&entry->imsi_deny_re, mi_string, 0, NULL, 0) == 0) { - *cm_cause = entry->cm_reject_cause; - *lu_cause = entry->lu_reject_cause; - return 0; - } - } - - return 1; -} - -/* apply white/black list */ -static int auth_imsi(struct bsc_connection *bsc, const char *imsi, - struct bsc_nat_reject_cause *cause) -{ - /* - * Now apply blacklist/whitelist of the BSC and the NAT. - * 1.) Check the global IMSI barr list - * 2.) Allow directly if the IMSI is allowed at the BSC - * 3.) Reject if the IMSI is not allowed at the BSC - * 4.) Reject if the IMSI not allowed at the global level. - * 5.) Allow directly if the IMSI is allowed at the global level - */ - int cm, lu; - struct bsc_nat_acc_lst *nat_lst = NULL; - struct bsc_nat_acc_lst *bsc_lst = NULL; - - /* 1. global check for barred imsis */ - if (bsc_nat_barr_find(&bsc->nat->imsi_black_list, imsi, &cm, &lu)) { - cause->cm_reject_cause = cm; - cause->lu_reject_cause = lu; - LOGP(DNAT, LOGL_DEBUG, - "Blocking subscriber IMSI %s with CM: %d LU: %d\n", - imsi, cm, lu); - return -4; - } - - - bsc_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->cfg->acc_lst_name); - nat_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->nat->acc_lst_name); - - - if (bsc_lst) { - /* 2. BSC allow */ - if (bsc_nat_lst_check_allow(bsc_lst, imsi) == 0) - return 1; - - /* 3. BSC deny */ - if (lst_check_deny(bsc_lst, imsi, &cm, &lu) == 0) { - LOGP(DNAT, LOGL_ERROR, - "Filtering %s by imsi_deny on bsc nr: %d.\n", imsi, bsc->cfg->nr); - rate_ctr_inc(&bsc_lst->stats->ctr[ACC_LIST_BSC_FILTER]); - cause->cm_reject_cause = cm; - cause->lu_reject_cause = lu; - return -2; - } - - } - - /* 4. NAT deny */ - if (nat_lst) { - if (lst_check_deny(nat_lst, imsi, &cm, &lu) == 0) { - LOGP(DNAT, LOGL_ERROR, - "Filtering %s by nat imsi_deny on bsc nr: %d.\n", imsi, bsc->cfg->nr); - rate_ctr_inc(&nat_lst->stats->ctr[ACC_LIST_NAT_FILTER]); - cause->cm_reject_cause = cm; - cause->lu_reject_cause = lu; - return -3; - } - } - - return 1; -} - -static int _cr_check_loc_upd(struct bsc_connection *bsc, - uint8_t *data, unsigned int length, - char **imsi) -{ - uint8_t mi_type; - struct gsm48_loc_upd_req *lu; - char mi_string[GSM48_MI_SIZE]; - - if (length < sizeof(*lu)) { - LOGP(DNAT, LOGL_ERROR, - "LU does not fit. Length is %d \n", length); - return -1; - } - - lu = (struct gsm48_loc_upd_req *) data; - mi_type = lu->mi[0] & GSM_MI_TYPE_MASK; - - /* - * We can only deal with the IMSI. This will fail for a phone that - * will send the TMSI of a previous network to us. - */ - if (mi_type != GSM_MI_TYPE_IMSI) - return 0; - - gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len); - *imsi = talloc_strdup(bsc, mi_string); - return 1; -} - -static int _cr_check_cm_serv_req(struct bsc_connection *bsc, - uint8_t *data, unsigned int length, - int *con_type, char **imsi) -{ - static const uint32_t classmark_offset = - offsetof(struct gsm48_service_request, classmark); - - char mi_string[GSM48_MI_SIZE]; - uint8_t mi_type; - int rc; - struct gsm48_service_request *req; - - /* unfortunately in Phase1 the classmark2 length is variable */ - - if (length < sizeof(*req)) { - LOGP(DNAT, LOGL_ERROR, - "CM Serv Req does not fit. Length is %d\n", length); - return -1; - } - - req = (struct gsm48_service_request *) data; - if (req->cm_service_type == 0x8) - *con_type = NAT_CON_TYPE_SSA; - rc = gsm48_extract_mi((uint8_t *) &req->classmark, - length - classmark_offset, mi_string, &mi_type); - if (rc < 0) { - LOGP(DNAT, LOGL_ERROR, "Failed to parse the classmark2/mi. error: %d\n", rc); - return -1; - } - - /* we have to let the TMSI or such pass */ - if (mi_type != GSM_MI_TYPE_IMSI) - return 0; - - *imsi = talloc_strdup(bsc, mi_string); - return 1; -} - -static int _cr_check_pag_resp(struct bsc_connection *bsc, - uint8_t *data, unsigned int length, char **imsi) -{ - struct gsm48_pag_resp *resp; - char mi_string[GSM48_MI_SIZE]; - uint8_t mi_type; - - if (length < sizeof(*resp)) { - LOGP(DNAT, LOGL_ERROR, "PAG RESP does not fit. Length was %d.\n", length); - return -1; - } - - resp = (struct gsm48_pag_resp *) data; - if (gsm48_paging_extract_mi(resp, length, mi_string, &mi_type) < 0) { - LOGP(DNAT, LOGL_ERROR, "Failed to extract the MI.\n"); - return -1; - } - - /* we need to let it pass for now */ - if (mi_type != GSM_MI_TYPE_IMSI) - return 0; - - *imsi = talloc_strdup(bsc, mi_string); - return 1; -} - -static int _dt_check_id_resp(struct bsc_connection *bsc, - uint8_t *data, unsigned int length, - struct nat_sccp_connection *con, - struct bsc_nat_reject_cause *cause) -{ - char mi_string[GSM48_MI_SIZE]; - uint8_t mi_type; - - if (length < 2) { - LOGP(DNAT, LOGL_ERROR, "mi does not fit.\n"); - return -1; - } - - if (data[0] < length - 1) { - LOGP(DNAT, LOGL_ERROR, "mi length too big.\n"); - return -2; - } - - mi_type = data[1] & GSM_MI_TYPE_MASK; - gsm48_mi_to_string(mi_string, sizeof(mi_string), &data[1], data[0]); - - if (mi_type != GSM_MI_TYPE_IMSI) - return 0; - - con->imsi_checked = 1; - con->imsi = talloc_strdup(con, mi_string); - return auth_imsi(bsc, mi_string, cause); -} - - -/* Filter out CR data... */ -int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg, - struct bsc_nat_parsed *parsed, int *con_type, - char **imsi, struct bsc_nat_reject_cause *cause) -{ - struct tlv_parsed tp; - struct gsm48_hdr *hdr48; - int hdr48_len; - int len, ret = 0; - uint8_t msg_type, proto; - - *con_type = NAT_CON_TYPE_NONE; - cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; - cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; - *imsi = NULL; - - if (parsed->gsm_type != BSS_MAP_MSG_COMPLETE_LAYER_3) { - LOGP(DNAT, LOGL_ERROR, - "Rejecting CR message due wrong GSM Type %d\n", parsed->gsm_type); - return -1; - } - - /* the parsed has had some basic l3 length check */ - len = msg->l3h[1]; - if (msgb_l3len(msg) - 3 < len) { - LOGP(DNAT, LOGL_ERROR, - "The CR Data has not enough space...\n"); - return -1; - } - - msg->l4h = &msg->l3h[3]; - len -= 1; - - tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h, len, 0, 0); - - if (!TLVP_PRESENT(&tp, GSM0808_IE_LAYER_3_INFORMATION)) { - LOGP(DNAT, LOGL_ERROR, "CR Data does not contain layer3 information.\n"); - return -1; - } - - hdr48_len = TLVP_LEN(&tp, GSM0808_IE_LAYER_3_INFORMATION); - - if (hdr48_len < sizeof(*hdr48)) { - LOGP(DNAT, LOGL_ERROR, "GSM48 header does not fit.\n"); - return -1; - } - - hdr48 = (struct gsm48_hdr *) TLVP_VAL(&tp, GSM0808_IE_LAYER_3_INFORMATION); - - proto = hdr48->proto_discr & 0x0f; - msg_type = hdr48->msg_type & 0xbf; - if (proto == GSM48_PDISC_MM && - msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) { - *con_type = NAT_CON_TYPE_LU; - ret = _cr_check_loc_upd(bsc, &hdr48->data[0], - hdr48_len - sizeof(*hdr48), imsi); - } else if (proto == GSM48_PDISC_MM && - msg_type == GSM48_MT_MM_CM_SERV_REQ) { - *con_type = NAT_CON_TYPE_CM_SERV_REQ; - ret = _cr_check_cm_serv_req(bsc, &hdr48->data[0], - hdr48_len - sizeof(*hdr48), - con_type, imsi); - } else if (proto == GSM48_PDISC_RR && - msg_type == GSM48_MT_RR_PAG_RESP) { - *con_type = NAT_CON_TYPE_PAG_RESP; - ret = _cr_check_pag_resp(bsc, &hdr48->data[0], - hdr48_len - sizeof(*hdr48), imsi); - } else { - /* We only want to filter the above, let other things pass */ - *con_type = NAT_CON_TYPE_OTHER; - return 0; - } - - /* check if we are done */ - if (ret != 1) - return ret; - - /* the memory allocation failed */ - if (!*imsi) - return -1; - - /* now check the imsi */ - return auth_imsi(bsc, *imsi, cause); -} - -int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg, - struct nat_sccp_connection *con, struct bsc_nat_parsed *parsed, - struct bsc_nat_reject_cause *cause) -{ - uint32_t len; - uint8_t msg_type, proto; - struct gsm48_hdr *hdr48; - - cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; - cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; - - if (con->imsi_checked) - return 0; - - /* only care about DTAP messages */ - if (parsed->bssap != BSSAP_MSG_DTAP) - return 0; - - hdr48 = bsc_unpack_dtap(parsed, msg, &len); - if (!hdr48) - return -1; - - proto = hdr48->proto_discr & 0x0f; - msg_type = hdr48->msg_type & 0xbf; - if (proto != GSM48_PDISC_MM || msg_type != GSM48_MT_MM_ID_RESP) - return 0; - - return _dt_check_id_resp(bsc, &hdr48->data[0], - len - sizeof(*hdr48), con, cause); -} |