diff options
Diffstat (limited to 'openbsc/src/libfilter')
| -rw-r--r-- | openbsc/src/libfilter/Makefile.am | 11 | ||||
| -rw-r--r-- | openbsc/src/libfilter/bsc_msg_acc.c | 116 | ||||
| -rw-r--r-- | openbsc/src/libfilter/bsc_msg_filter.c | 401 | ||||
| -rw-r--r-- | openbsc/src/libfilter/bsc_msg_vty.c | 140 |
4 files changed, 668 insertions, 0 deletions
diff --git a/openbsc/src/libfilter/Makefile.am b/openbsc/src/libfilter/Makefile.am new file mode 100644 index 000000000..4dbc59041 --- /dev/null +++ b/openbsc/src/libfilter/Makefile.am @@ -0,0 +1,11 @@ +AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir) +AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) \ + $(LIBOSMOVTY_CFLAGS) $(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS) + +noinst_LIBRARIES = libfilter.a + +libfilter_a_SOURCES = \ + bsc_msg_filter.c \ + bsc_msg_acc.c \ + bsc_msg_vty.c + diff --git a/openbsc/src/libfilter/bsc_msg_acc.c b/openbsc/src/libfilter/bsc_msg_acc.c new file mode 100644 index 000000000..6258b3577 --- /dev/null +++ b/openbsc/src/libfilter/bsc_msg_acc.c @@ -0,0 +1,116 @@ +/* + * (C) 2010-2015 by Holger Hans Peter Freyther <zecke@selfish.org> + * (C) 2010-2011 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_msg_filter.h> +#include <openbsc/bsc_nat.h> + +#include <osmocom/core/rate_ctr.h> + +#include <string.h> + +static const struct rate_ctr_desc acc_list_ctr_description[] = { + [ACC_LIST_LOCAL_FILTER] = { "access-list.local-filter", "Rejected by rule for local"}, + [ACC_LIST_GLOBAL_FILTER]= { "access-list.global-filter", "Rejected by rule for global"}, +}; + +static const struct rate_ctr_group_desc bsc_cfg_acc_list_desc = { + .group_name_prefix = "nat.filter", + .group_description = "NAT Access-List Statistics", + .num_ctr = ARRAY_SIZE(acc_list_ctr_description), + .ctr_desc = acc_list_ctr_description, +}; + + +int bsc_msg_acc_lst_check_allow(struct bsc_msg_acc_lst *lst, const char *mi_string) +{ + struct bsc_msg_acc_lst_entry *entry; + + llist_for_each_entry(entry, &lst->fltr_list, list) { + if (!entry->imsi_allow) + continue; + if (regexec(&entry->imsi_allow_re, mi_string, 0, NULL, 0) == 0) + return 0; + } + + return 1; +} + +struct bsc_msg_acc_lst *bsc_msg_acc_lst_find(struct llist_head *head, const char *name) +{ + struct bsc_msg_acc_lst *lst; + + if (!name) + return NULL; + + llist_for_each_entry(lst, head, list) + if (strcmp(lst->name, name) == 0) + return lst; + + return NULL; +} + +struct bsc_msg_acc_lst *bsc_msg_acc_lst_get(void *ctx, struct llist_head *head, const char *name) +{ + struct bsc_msg_acc_lst *lst; + + lst = bsc_msg_acc_lst_find(head, name); + if (lst) + return lst; + + lst = talloc_zero(ctx, struct bsc_msg_acc_lst); + if (!lst) { + LOGP(DNAT, LOGL_ERROR, "Failed to allocate access list"); + return NULL; + } + + /* TODO: get the index right */ + lst->stats = rate_ctr_group_alloc(lst, &bsc_cfg_acc_list_desc, 0); + if (!lst->stats) { + talloc_free(lst); + return NULL; + } + + INIT_LLIST_HEAD(&lst->fltr_list); + lst->name = talloc_strdup(lst, name); + llist_add_tail(&lst->list, head); + return lst; +} + +void bsc_msg_acc_lst_delete(struct bsc_msg_acc_lst *lst) +{ + llist_del(&lst->list); + rate_ctr_group_free(lst->stats); + talloc_free(lst); +} + +struct bsc_msg_acc_lst_entry *bsc_msg_acc_lst_entry_create(struct bsc_msg_acc_lst *lst) +{ + struct bsc_msg_acc_lst_entry *entry; + + entry = talloc_zero(lst, struct bsc_msg_acc_lst_entry); + if (!entry) + return NULL; + + entry->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; + entry->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; + llist_add_tail(&entry->list, &lst->fltr_list); + return entry; +} + diff --git a/openbsc/src/libfilter/bsc_msg_filter.c b/openbsc/src/libfilter/bsc_msg_filter.c new file mode 100644 index 000000000..be518a478 --- /dev/null +++ b/openbsc/src/libfilter/bsc_msg_filter.c @@ -0,0 +1,401 @@ +/* + * Access filtering + */ +/* + * (C) 2010-2015 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_msg_filter.h> + +#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/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_filter_barr_find(struct rb_root *root, const char *imsi, int *cm, int *lu) +{ + struct bsc_filter_barr_entry *n; + n = rb_entry(root->rb_node, struct bsc_filter_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_filter_barr_entry, node); + }; + + return 0; +} + +static int insert_barr_node(struct bsc_filter_barr_entry *entry, struct rb_root *root) +{ + struct rb_node **new = &root->rb_node, *parent = NULL; + + while (*new) { + int rc; + struct bsc_filter_barr_entry *this; + this = rb_entry(*new, struct bsc_filter_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(DFILTER, 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_filter_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_filter_barr_entry *entry; + entry = talloc_zero(ctx, struct bsc_filter_barr_entry); + if (!entry) { + LOGP(DFILTER, 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_msg_acc_lst *lst, const char *mi_string, + int *cm_cause, int *lu_cause) +{ + struct bsc_msg_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_filter_request *req, + const char *imsi, + struct bsc_filter_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_msg_acc_lst *nat_lst = NULL; + struct bsc_msg_acc_lst *bsc_lst = NULL; + + /* 1. global check for barred imsis */ + if (req->black_list && bsc_filter_barr_find(req->black_list, imsi, &cm, &lu)) { + cause->cm_reject_cause = cm; + cause->lu_reject_cause = lu; + LOGP(DFILTER, LOGL_DEBUG, + "Blocking subscriber IMSI %s with CM: %d LU: %d\n", + imsi, cm, lu); + return -4; + } + + + bsc_lst = bsc_msg_acc_lst_find(req->access_lists, req->local_lst_name); + nat_lst = bsc_msg_acc_lst_find(req->access_lists, req->global_lst_name); + + + if (bsc_lst) { + /* 2. BSC allow */ + if (bsc_msg_acc_lst_check_allow(bsc_lst, imsi) == 0) + return 1; + + /* 3. BSC deny */ + if (lst_check_deny(bsc_lst, imsi, &cm, &lu) == 0) { + LOGP(DFILTER, LOGL_ERROR, + "Filtering %s by imsi_deny on config nr: %d.\n", imsi, req->bsc_nr); + rate_ctr_inc(&bsc_lst->stats->ctr[ACC_LIST_LOCAL_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(DFILTER, LOGL_ERROR, + "Filtering %s global imsi_deny on bsc nr: %d.\n", imsi, req->bsc_nr); + rate_ctr_inc(&nat_lst->stats->ctr[ACC_LIST_GLOBAL_FILTER]); + cause->cm_reject_cause = cm; + cause->lu_reject_cause = lu; + return -3; + } + } + + return 1; +} + +static int _cr_check_loc_upd(void *ctx, + 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(DFILTER, 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(ctx, mi_string); + return 1; +} + +static int _cr_check_cm_serv_req(void *ctx, + 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(DFILTER, 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 = FLT_CON_TYPE_SSA; + rc = gsm48_extract_mi((uint8_t *) &req->classmark, + length - classmark_offset, mi_string, &mi_type); + if (rc < 0) { + LOGP(DFILTER, 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(ctx, mi_string); + return 1; +} + +static int _cr_check_pag_resp(void *ctx, + 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(DFILTER, 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(DFILTER, 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(ctx, mi_string); + return 1; +} + +static int _dt_check_id_resp(struct bsc_filter_request *req, + uint8_t *data, unsigned int length, + struct bsc_filter_state *state, + struct bsc_filter_reject_cause *cause) +{ + char mi_string[GSM48_MI_SIZE]; + uint8_t mi_type; + + if (length < 2) { + LOGP(DFILTER, LOGL_ERROR, "mi does not fit.\n"); + return -1; + } + + if (data[0] < length - 1) { + LOGP(DFILTER, 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; + + state->imsi_checked = 1; + state->imsi = talloc_strdup(req->ctx, mi_string); + return auth_imsi(req, mi_string, cause); +} + + +/* Filter out CR data... */ +int bsc_msg_filter_initial(struct gsm48_hdr *hdr48, size_t hdr48_len, + struct bsc_filter_request *req, + int *con_type, + char **imsi, struct bsc_filter_reject_cause *cause) +{ + int ret = 0; + uint8_t msg_type, proto; + + *con_type = FLT_CON_TYPE_NONE; + cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; + cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; + *imsi = NULL; + + 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 = FLT_CON_TYPE_LU; + ret = _cr_check_loc_upd(req->ctx, &hdr48->data[0], + hdr48_len - sizeof(*hdr48), imsi); + } else if (proto == GSM48_PDISC_MM && + msg_type == GSM48_MT_MM_CM_SERV_REQ) { + *con_type = FLT_CON_TYPE_CM_SERV_REQ; + ret = _cr_check_cm_serv_req(req->ctx, &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 = FLT_CON_TYPE_PAG_RESP; + ret = _cr_check_pag_resp(req->ctx, &hdr48->data[0], + hdr48_len - sizeof(*hdr48), imsi); + } else { + /* We only want to filter the above, let other things pass */ + *con_type = FLT_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(req, *imsi, cause); +} + +int bsc_msg_filter_data(struct gsm48_hdr *hdr48, size_t len, + struct bsc_filter_request *req, + struct bsc_filter_state *state, + struct bsc_filter_reject_cause *cause) +{ + uint8_t msg_type, proto; + + cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; + cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED; + + if (state->imsi_checked) + return 0; + + 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(req, &hdr48->data[0], + len - sizeof(*hdr48), state, cause); +} diff --git a/openbsc/src/libfilter/bsc_msg_vty.c b/openbsc/src/libfilter/bsc_msg_vty.c new file mode 100644 index 000000000..c342fdca0 --- /dev/null +++ b/openbsc/src/libfilter/bsc_msg_vty.c @@ -0,0 +1,140 @@ +/* (C) 2010-2015 by Holger Hans Peter Freyther + * (C) 2010-2013 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_msg_filter.h> +#include <openbsc/gsm_data.h> +#include <openbsc/vty.h> + +#include <osmocom/vty/misc.h> + +static struct llist_head *_acc_lst; +static void *_ctx; + +DEFUN(cfg_lst_no, + cfg_lst_no_cmd, + "no access-list NAME", + NO_STR "Remove an access-list by name\n" + "The access-list to remove\n") +{ + struct bsc_msg_acc_lst *acc; + acc = bsc_msg_acc_lst_find(_acc_lst, argv[0]); + if (!acc) + return CMD_WARNING; + + bsc_msg_acc_lst_delete(acc); + return CMD_SUCCESS; +} + +DEFUN(show_acc_lst, + show_acc_lst_cmd, + "show access-list NAME", + SHOW_STR "IMSI access list\n" "Name of the access list\n") +{ + struct bsc_msg_acc_lst *acc; + acc = bsc_msg_acc_lst_find(_acc_lst, argv[0]); + if (!acc) + return CMD_WARNING; + + vty_out(vty, "access-list %s%s", acc->name, VTY_NEWLINE); + vty_out_rate_ctr_group(vty, " ", acc->stats); + + return CMD_SUCCESS; +} + +DEFUN(cfg_lst_imsi_allow, + cfg_lst_imsi_allow_cmd, + "access-list NAME imsi-allow [REGEXP]", + "Access list commands\n" + "Name of the access list\n" + "Add allowed IMSI to the list\n" + "Regexp for IMSIs\n") +{ + struct bsc_msg_acc_lst *acc; + struct bsc_msg_acc_lst_entry *entry; + + acc = bsc_msg_acc_lst_get(_ctx, _acc_lst, argv[0]); + if (!acc) + return CMD_WARNING; + + entry = bsc_msg_acc_lst_entry_create(acc); + if (!entry) + return CMD_WARNING; + + if (gsm_parse_reg(acc, &entry->imsi_allow_re, &entry->imsi_allow, argc - 1, &argv[1]) != 0) + return CMD_WARNING; + return CMD_SUCCESS; +} + +DEFUN(cfg_lst_imsi_deny, + cfg_lst_imsi_deny_cmd, + "access-list NAME imsi-deny [REGEXP] (<0-256>) (<0-256>)", + "Access list commands\n" + "Name of the access list\n" + "Add denied IMSI to the list\n" + "Regexp for IMSIs\n" + "CM Service Reject reason\n" + "LU Reject reason\n") +{ + struct bsc_msg_acc_lst *acc; + struct bsc_msg_acc_lst_entry *entry; + + acc = bsc_msg_acc_lst_get(_ctx, _acc_lst, argv[0]); + if (!acc) + return CMD_WARNING; + + entry = bsc_msg_acc_lst_entry_create(acc); + if (!entry) + return CMD_WARNING; + + if (gsm_parse_reg(acc, &entry->imsi_deny_re, &entry->imsi_deny, argc - 1, &argv[1]) != 0) + return CMD_WARNING; + if (argc >= 3) + entry->cm_reject_cause = atoi(argv[2]); + if (argc >= 4) + entry->lu_reject_cause = atoi(argv[3]); + return CMD_SUCCESS; +} + +void bsc_msg_acc_lst_write(struct vty *vty, struct bsc_msg_acc_lst *lst) +{ + struct bsc_msg_acc_lst_entry *entry; + + llist_for_each_entry(entry, &lst->fltr_list, list) { + if (entry->imsi_allow) + vty_out(vty, " access-list %s imsi-allow %s%s", + lst->name, entry->imsi_allow, VTY_NEWLINE); + if (entry->imsi_deny) + vty_out(vty, " access-list %s imsi-deny %s %d %d%s", + lst->name, entry->imsi_deny, + entry->cm_reject_cause, entry->lu_reject_cause, + VTY_NEWLINE); + } +} + +void bsc_msg_lst_vty_init(void *ctx, struct llist_head *lst, int node) +{ + _ctx = ctx; + _acc_lst = lst; + install_element_ve(&show_acc_lst_cmd); + + /* access-list */ + install_element(node, &cfg_lst_imsi_allow_cmd); + install_element(node, &cfg_lst_imsi_deny_cmd); + install_element(node, &cfg_lst_no_cmd); +} |