common_config.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2023, Sangoma Technologies Corporation
 *
 * George Joseph <gjoseph@sangoma.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
#include "asterisk.h"
#include "asterisk/cli.h"
#include "asterisk/cli.h"
#include "asterisk/logger.h"
#include "asterisk/module.h"
#include "asterisk/utils.h"
#include "asterisk/stasis.h"
#include "asterisk/security_events.h"
 
#define AST_API_MODULE
#include "stir_shaken.h"
 
static struct ast_sorcery *sorcery;
struct stasis_subscription *named_acl_changed_sub = NULL;
 
struct ast_sorcery *get_sorcery(void)
{
    return sorcery;
}
 
#define generate_bool_handler_functions(param_name) \
static const char *param_name ## _map[] = { \
    [ param_name ## _NOT_SET ] = "not_set", \
    [ param_name ## _YES ] = "yes", \
    [ param_name ## _NO ] = "no", \
}; \
enum param_name ## _enum \
    param_name ## _from_str(const char *value) \
{ \
    if (!strcasecmp(value, param_name ## _map[param_name ## _NOT_SET])) { \
        return param_name ## _NOT_SET; \
    } else if (ast_true(value)) { \
        return param_name ## _YES; \
    } else if (ast_false(value)) { \
        return param_name ## _NO; \
    } \
    ast_log(LOG_WARNING, "Unknown " #param_name " response value '%s'\n", value); \
    return param_name ## _UNKNOWN; \
}\
const char *param_name ## _to_str(enum param_name ## _enum value) \
{ \
    return ARRAY_IN_BOUNDS(value, param_name ## _map) ? \
        param_name ## _map[value] : NULL; \
}
 
generate_bool_handler_functions(use_rfc9410_responses);
generate_bool_handler_functions(ignore_sip_date_header);
generate_bool_handler_functions(send_mky);
generate_bool_handler_functions(check_tn_cert_public_url);
generate_bool_handler_functions(relax_x5u_port_scheme_restrictions);
generate_bool_handler_functions(relax_x5u_path_restrictions);
 
generate_bool_handler_functions(load_system_certs);
 
struct enum_name_xref_entry {
    int value;
    const char *name;
};
 
#define generate_enum_string_functions(param_name, default_value, ...)\
static struct enum_name_xref_entry param_name ## _map[] = { \
    __VA_ARGS__ \
} ; \
enum param_name ## _enum param_name ## _from_str( \
    const char *value) \
{ \
    int i; \
    for (i = 0; i < ARRAY_LEN(param_name ## _map); i++) { \
        if (strcasecmp(value, param_name ##_map[i].name) == 0) { \
            return param_name ##_map[i].value; \
        } \
    } \
    return param_name ## _ ## default_value; \
} \
const char *param_name ## _to_str( \
    enum param_name ## _enum value) \
{ \
    int i; \
    for (i = 0; i < ARRAY_LEN(param_name ## _map); i++) { \
        if (value == param_name ## _map[i].value) return param_name ## _map[i].name; \
    } \
    return NULL; \
}
 
generate_enum_string_functions(attest_level, UNKNOWN,
    {attest_level_NOT_SET, "not_set"},
    {attest_level_A, "A"},
    {attest_level_B, "B"},
    {attest_level_C, "C"},
);
 
generate_enum_string_functions(endpoint_behavior, OFF,
    {endpoint_behavior_OFF,  "off"},
    {endpoint_behavior_OFF,  "none"},
    {endpoint_behavior_ATTEST, "attest"},
    {endpoint_behavior_VERIFY, "verify"},
    {endpoint_behavior_ON, "on"},
    {endpoint_behavior_ON, "both"}
);
 
generate_enum_string_functions(stir_shaken_failure_action, CONTINUE,
    {stir_shaken_failure_action_CONTINUE, "continue"},
    {stir_shaken_failure_action_REJECT_REQUEST, "reject_request"},
    {stir_shaken_failure_action_CONTINUE_RETURN_REASON, "continue_return_reason"},
);
 
static const char *translate_value(const char *val)
{
    if (val[0] == '0'
        || val[0] == '\0'
        || strcmp(val, "not_set") == 0) {
        return "";
    }
 
    return val;
}
 
static void print_acl(int fd, struct ast_acl_list *acl_list, const char *prefix)
{
    struct ast_acl *acl;
 
    AST_LIST_LOCK(acl_list);
    AST_LIST_TRAVERSE(acl_list, acl, list) {
        if (ast_strlen_zero(acl->name)) {
            ast_cli(fd, "%s(permit/deny)\n", prefix);
        } else {
            ast_cli(fd, "%s%s\n", prefix, acl->name);
        }
        ast_ha_output(fd, acl->acl, prefix);
    }
    AST_LIST_UNLOCK(acl_list);
}
 
#define print_acl_cert_store(cfg, a, max_name_len) \
({ \
    if (cfg->vcfg_common.acl) { \
        ast_cli(a->fd, "x5u_acl:\n"); \
        print_acl(a->fd, cfg->vcfg_common.acl, "   "); \
    } else { \
        ast_cli(a->fd, "%-*s: (none)\n", max_name_len, "x5u_acl"); \
    }\
    if (cfg->vcfg_common.tcs) { \
        int count = 0; \
        ast_cli(a->fd, "%-*s:\n", max_name_len, "Verification CA certificate store"); \
        count = crypto_show_cli_store(cfg->vcfg_common.tcs, a->fd); \
        if (count == 0 && (!ast_strlen_zero(cfg->vcfg_common.ca_path) \
            || !ast_strlen_zero(cfg->vcfg_common.crl_path))) { \
            ast_cli(a->fd, "   Note: Certs in ca_path or crl_path won't show until used.\n"); \
        } \
    } else { \
        ast_cli(a->fd, "%-*s: (none)\n", max_name_len, "Verification CA certificate store"); \
    } \
})
 
int config_object_cli_show(void *obj, void *arg, void *data, int flags)
{
    struct ast_cli_args *a = arg;
    struct config_object_cli_data *cli_data = data;
    struct ast_variable *options;
    struct ast_variable *i;
    const char *title = NULL;
    const char *cfg_name = NULL;
    int max_name_len = 0;
 
    if (!obj) {
        ast_cli(a->fd, "No stir/shaken configuration found\n");
        return 0;
    }
 
    if (!ast_strlen_zero(cli_data->title)) {
        title = cli_data->title;
    } else {
        title = ast_sorcery_object_get_type(obj);
    }
    max_name_len = strlen(title);
 
    if (cli_data->object_type == config_object_type_profile
        || cli_data->object_type == config_object_type_tn) {
        cfg_name = ast_sorcery_object_get_id(obj);
        max_name_len += strlen(cfg_name) + 2 /* ": " */;
    }
 
    options = ast_variable_list_sort(ast_sorcery_objectset_create2(
        get_sorcery(), obj, AST_HANDLER_ONLY_STRING));
    if (!options) {
        return 0;
    }
 
    for (i = options; i; i = i->next) {
        int nlen = strlen(i->name);
        max_name_len = (nlen > max_name_len) ? nlen : max_name_len;
    }
 
    ast_cli(a->fd, "\n==============================================================================\n");
    if (ast_strlen_zero(cfg_name))  {
        ast_cli(a->fd, "%s\n", title);
    } else {
        ast_cli(a->fd, "%s: %s\n", title, cfg_name);
    }
    ast_cli(a->fd, "------------------------------------------------------------------------------\n");
 
    for (i = options; i; i = i->next) {
        if (!ast_strings_equal(i->name, "x5u_acl")) {
            ast_cli(a->fd, "%-*s: %s\n", max_name_len, i->name,
                translate_value(i->value));
        }
    }
 
    ast_variables_destroy(options);
 
    if (cli_data->object_type == config_object_type_profile) {
        struct profile_cfg *cfg = obj;
        print_acl_cert_store(cfg, a, max_name_len);
    } else if (cli_data->object_type == config_object_type_verification) {
        struct verification_cfg *cfg = obj;
        print_acl_cert_store(cfg, a, max_name_len);
    }
    ast_cli(a->fd, "---------------------------------------------\n\n"); \
 
    return 0;
}
 
char *config_object_tab_complete_name(const char *word, struct ao2_container *container)
{
    void *obj;
    struct ao2_iterator it;
    int wordlen = strlen(word);
    int ret;
 
    it = ao2_iterator_init(container, 0);
    while ((obj = ao2_iterator_next(&it))) {
        if (!strncasecmp(word, ast_sorcery_object_get_id(obj), wordlen)) {
            ret = ast_cli_completion_add(ast_strdup(ast_sorcery_object_get_id(obj)));
            if (ret) {
                ao2_ref(obj, -1);
                break;
            }
        }
        ao2_ref(obj, -1);
    }
    ao2_iterator_destroy(&it);
 
    return NULL;
}
 
 
/* Remove everything except 0-9, *, and # in telephone number according to RFC 8224
 * (required by RFC 8225 as part of canonicalization) */
char *canonicalize_tn(const char *tn, char *dest_tn)
{
    int i;
    const char *s = tn;
    size_t len = tn ? strlen(tn) : 0;
    char *new_tn = dest_tn;
    SCOPE_ENTER(3, "tn: %s\n", S_OR(tn, "(null)"));
 
    if (ast_strlen_zero(tn)) {
        *dest_tn = '\0';
        SCOPE_EXIT_RTN_VALUE(NULL, "Empty TN\n");
    }
 
    if (!dest_tn) {
        SCOPE_EXIT_RTN_VALUE(NULL, "No destination buffer\n");
    }
 
    for (i = 0; i < len; i++) {
        if (isdigit(*s) || *s == '#' || *s == '*') { /* Only characters allowed */
            *new_tn++ = *s;
        }
        s++;
    }
    *new_tn = '\0';
    SCOPE_EXIT_RTN_VALUE(dest_tn, "Canonicalized '%s' -> '%s'\n", tn, dest_tn);
}
 
char *canonicalize_tn_alloc(const char *tn)
{
    char *canon_tn = ast_strlen_zero(tn) ? NULL : ast_malloc(strlen(tn) + 1);
    if (!canon_tn) {
        return NULL;
    }
    return canonicalize_tn(tn, canon_tn);
}
 
static char *cli_verify_cert(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
    RAII_VAR(struct profile_cfg *, profile, NULL, ao2_cleanup);
    RAII_VAR(struct verification_cfg *, vs_cfg, NULL, ao2_cleanup);
    struct crypto_cert_store *tcs;
    X509 *cert = NULL;
    STACK_OF(X509) *cert_chain = NULL;
    const char *errmsg = NULL;
 
    switch(cmd) {
    case CLI_INIT:
        e->command = "stir_shaken verify certificate_file";
        e->usage =
            "Usage: stir_shaken verify certificate_file <certificate_file> [ <profile> ]\n"
            "       Verify an external certificate file against the global or profile verification store\n";
        return NULL;
    case CLI_GENERATE:
        if (a->pos == 4) {
            return config_object_tab_complete_name(a->word, profile_get_all());
        } else {
            return NULL;
        }
    }
 
    if (a->argc < 4) {
        return CLI_SHOWUSAGE;
    }
 
    if (a->argc == 5) {
        profile = profile_get_cfg(a->argv[4]);
        if (!profile) {
            ast_cli(a->fd, "Profile %s doesn't exist\n", a->argv[4]);
            return CLI_SUCCESS;
        }
        if (!profile->vcfg_common.tcs) {
            ast_cli(a->fd,"Profile %s doesn't have a certificate store\n", a->argv[4]);
            return CLI_SUCCESS;
        }
        tcs = profile->vcfg_common.tcs;
    } else {
        vs_cfg = vs_get_cfg();
        if (!vs_cfg) {
            ast_cli(a->fd, "No verification store found\n");
            return CLI_SUCCESS;
        }
        tcs = vs_cfg->vcfg_common.tcs;
    }
 
    cert = crypto_load_cert_chain_from_file(a->argv[3], &cert_chain);
    if (!cert) {
        ast_cli(a->fd, "Failed to load certificate from %s.  See log for details\n", a->argv[3]);
        return CLI_SUCCESS;
    }
 
    if (crypto_is_cert_trusted(tcs, cert, cert_chain, &errmsg)) {
        ast_cli(a->fd, "Certificate %s trusted\n", a->argv[3]);
    } else {
        ast_cli(a->fd, "Certificate %s NOT trusted: %s\n", a->argv[3], errmsg);
    }
    X509_free(cert);
    if (cert_chain) {
        sk_X509_pop_free(cert_chain, X509_free);
    }
 
    return CLI_SUCCESS;
}
 
static struct ast_cli_entry cli_commands[] = {
    AST_CLI_DEFINE(cli_verify_cert, "Verify a certificate file against the global or a profile verification store"),
};
 
int common_config_reload(void)
{
    SCOPE_ENTER(2, "Stir Shaken Reload\n");
    if (vs_reload()) {
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken VS Reload failed\n");
    }
 
    if (as_reload()) {
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken AS Reload failed\n");
    }
 
    if (tn_config_reload()) {
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken TN Reload failed\n");
    }
 
    if (profile_reload()) {
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken Profile Reload failed\n");
    }
 
    SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_SUCCESS, "Stir Shaken Reload Done\n");
}
 
int common_config_unload(void)
{
    ast_cli_unregister_multiple(cli_commands, ARRAY_LEN(cli_commands));
 
    profile_unload();
    tn_config_unload();
    as_unload();
    vs_unload();
 
    if (named_acl_changed_sub) {
        stasis_unsubscribe(named_acl_changed_sub);
        named_acl_changed_sub = NULL;
    }
    ast_sorcery_unref(sorcery);
    sorcery = NULL;
 
    return 0;
}
 
static void named_acl_changed_cb(void *data,
    struct stasis_subscription *sub, struct stasis_message *message)
{
    if (stasis_message_type(message) != ast_named_acl_change_type()) {
        return;
    }
    ast_log(LOG_NOTICE, "Named acl changed.  Reloading verification and profile\n");
    common_config_reload();
}
 
int common_config_load(void)
{
    SCOPE_ENTER(2, "Stir Shaken Load\n");
 
    if (!(sorcery = ast_sorcery_open())) {
        common_config_unload();
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken sorcery load failed\n");
    }
 
    if (vs_load()) {
        common_config_unload();
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken VS load failed\n");
    }
 
    if (as_load()) {
        common_config_unload();
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken AS load failed\n");
    }
 
    if (tn_config_load()) {
        common_config_unload();
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken TN load failed\n");
    }
 
    if (profile_load()) {
        common_config_unload();
        SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken profile load failed\n");
    }
 
    if (!named_acl_changed_sub) {
        named_acl_changed_sub = stasis_subscribe(ast_security_topic(),
            named_acl_changed_cb, NULL);
        if (!named_acl_changed_sub) {
            common_config_unload();
            SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_DECLINE, "Stir Shaken acl change subscribe failed\n");
        }
        stasis_subscription_accept_message_type(
            named_acl_changed_sub, ast_named_acl_change_type());
    }
 
    ast_cli_register_multiple(cli_commands, ARRAY_LEN(cli_commands));
 
    SCOPE_EXIT_RTN_VALUE(AST_MODULE_LOAD_SUCCESS, "Stir Shaken Load Done\n");
}