ASTERISK-23919 #close Reported by Malcolm Davenport Review: https://reviewboard.asterisk.org/r/3802 git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@419592 65c4cc65-6c06-0410-ace0-fbb531ad65f3
492 lines
14 KiB
C
492 lines
14 KiB
C
/*
|
|
* Asterisk -- An open source telephony toolkit.
|
|
*
|
|
* Copyright (C) 2013, Digium, Inc.
|
|
*
|
|
* Mark Michelson <mmichelson@digium.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 <pjsip.h>
|
|
|
|
#include "asterisk/res_pjsip.h"
|
|
#include "asterisk/logger.h"
|
|
#include "asterisk/module.h"
|
|
#include "asterisk/strings.h"
|
|
|
|
/*** MODULEINFO
|
|
<depend>pjproject</depend>
|
|
<depend>res_pjsip</depend>
|
|
<support_level>core</support_level>
|
|
***/
|
|
|
|
AO2_GLOBAL_OBJ_STATIC(entity_id);
|
|
|
|
/*!
|
|
* \brief Determine if authentication is required
|
|
*
|
|
* Authentication is required if the endpoint has at least one auth
|
|
* section specified
|
|
*/
|
|
static int digest_requires_authentication(struct ast_sip_endpoint *endpoint, pjsip_rx_data *rdata)
|
|
{
|
|
RAII_VAR(struct ast_sip_endpoint *, artificial, ast_sip_get_artificial_endpoint(), ao2_cleanup);
|
|
|
|
return endpoint == artificial || AST_VECTOR_SIZE(&endpoint->inbound_auths) > 0;
|
|
}
|
|
|
|
static void auth_store_cleanup(void *data)
|
|
{
|
|
struct ast_sip_auth **auth = data;
|
|
|
|
ao2_cleanup(*auth);
|
|
ast_free(data);
|
|
}
|
|
|
|
/*!
|
|
* \brief Thread-local storage for \ref ast_sip_auth
|
|
*
|
|
* The PJSIP authentication API is a bit annoying. When you set
|
|
* up an authentication server, you specify a lookup callback to
|
|
* call into when verifying incoming credentials. The problem
|
|
* with this callback is that it only gives you the realm and
|
|
* authentication username. In 2.0.5, there is a new version of
|
|
* the callback you can use that gives the pjsip_rx_data in
|
|
* addition.
|
|
*
|
|
* Unfortunately, the data we actually \b need is the
|
|
* \ref ast_sip_auth we are currently observing. So we have two
|
|
* choices:
|
|
* 1) Use the current PJSIP API and use thread-local storage
|
|
* to temporarily store our SIP authentication information. Then
|
|
* in the callback, we can retrieve the authentication info and
|
|
* use as needed. Given our threading model, this is safe.
|
|
* 2) Use the 2.0.5 API and temporarily store the authentication
|
|
* information in the rdata's endpoint_info. Then in the callback,
|
|
* we can retrieve the authentication info from the rdata.
|
|
*
|
|
* I've chosen option 1 since it does not require backporting
|
|
* any APIs from future versions of PJSIP, plus I feel the
|
|
* thread-local option is a bit cleaner.
|
|
*/
|
|
AST_THREADSTORAGE_CUSTOM(auth_store, NULL, auth_store_cleanup);
|
|
|
|
/*!
|
|
* \brief Store authentication information in thread-local storage
|
|
*/
|
|
static int store_auth(struct ast_sip_auth *auth)
|
|
{
|
|
struct ast_sip_auth **pointing;
|
|
pointing = ast_threadstorage_get(&auth_store, sizeof(pointing));
|
|
if (!pointing || *pointing) {
|
|
return -1;
|
|
}
|
|
|
|
ao2_ref(auth, +1);
|
|
*pointing = auth;
|
|
return 0;
|
|
}
|
|
|
|
/*!
|
|
* \brief Remove authentication information from thread-local storage
|
|
*/
|
|
static int remove_auth(void)
|
|
{
|
|
struct ast_sip_auth **pointing;
|
|
pointing = ast_threadstorage_get(&auth_store, sizeof(pointing));
|
|
if (!pointing) {
|
|
return -1;
|
|
}
|
|
|
|
ao2_cleanup(*pointing);
|
|
*pointing = NULL;
|
|
return 0;
|
|
}
|
|
|
|
/*!
|
|
* \brief Retrieve authentication information from thread-local storage
|
|
*/
|
|
static struct ast_sip_auth *get_auth(void)
|
|
{
|
|
struct ast_sip_auth **auth;
|
|
auth = ast_threadstorage_get(&auth_store, sizeof(auth));
|
|
if (auth && *auth) {
|
|
ao2_ref(*auth, +1);
|
|
return *auth;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*!
|
|
* \brief Lookup callback for authentication verification
|
|
*
|
|
* This function is called when we call pjsip_auth_srv_verify(). It
|
|
* expects us to verify that the realm and account name from the
|
|
* Authorization header is correct. We are then supposed to supply
|
|
* a password or MD5 sum of credentials.
|
|
*
|
|
* \param pool A memory pool we can use for allocations
|
|
* \param realm The realm from the Authorization header
|
|
* \param acc_name the user from the Authorization header
|
|
* \param[out] info The credentials we need to fill in
|
|
* \retval PJ_SUCCESS Successful authentication
|
|
* \retval other Unsuccessful
|
|
*/
|
|
static pj_status_t digest_lookup(pj_pool_t *pool, const pj_str_t *realm,
|
|
const pj_str_t *acc_name, pjsip_cred_info *info)
|
|
{
|
|
RAII_VAR(struct ast_sip_auth *, auth, get_auth(), ao2_cleanup);
|
|
if (!auth) {
|
|
return PJSIP_SC_FORBIDDEN;
|
|
}
|
|
|
|
if (auth->type == AST_SIP_AUTH_TYPE_ARTIFICIAL) {
|
|
return PJSIP_SC_FORBIDDEN;
|
|
}
|
|
|
|
if (pj_strcmp2(realm, auth->realm)) {
|
|
return PJSIP_SC_FORBIDDEN;
|
|
}
|
|
if (pj_strcmp2(acc_name, auth->auth_user)) {
|
|
return PJSIP_SC_FORBIDDEN;
|
|
}
|
|
|
|
pj_strdup2(pool, &info->realm, auth->realm);
|
|
pj_strdup2(pool, &info->username, auth->auth_user);
|
|
|
|
switch (auth->type) {
|
|
case AST_SIP_AUTH_TYPE_USER_PASS:
|
|
pj_strdup2(pool, &info->data, auth->auth_pass);
|
|
info->data_type = PJSIP_CRED_DATA_PLAIN_PASSWD;
|
|
break;
|
|
case AST_SIP_AUTH_TYPE_MD5:
|
|
pj_strdup2(pool, &info->data, auth->md5_creds);
|
|
info->data_type = PJSIP_CRED_DATA_DIGEST;
|
|
break;
|
|
default:
|
|
return PJSIP_SC_FORBIDDEN;
|
|
}
|
|
return PJ_SUCCESS;
|
|
}
|
|
|
|
/*!
|
|
* \brief Calculate a nonce
|
|
*
|
|
* We use this in order to create authentication challenges. We also use this in order
|
|
* to verify that an incoming request with credentials could be in response to one
|
|
* of our challenges.
|
|
*
|
|
* The nonce is calculated from a timestamp, the source IP address, the source port, a
|
|
* unique ID for us, and the realm. This helps to ensure that the incoming request
|
|
* is from the same source that the nonce was calculated for. Including the realm
|
|
* ensures that multiple challenges to the same request have different nonces.
|
|
*
|
|
* \param A UNIX timestamp expressed as a string
|
|
* \param rdata The incoming request
|
|
* \param realm The realm for which authentication should occur
|
|
*/
|
|
static int build_nonce(struct ast_str **nonce, const char *timestamp, const pjsip_rx_data *rdata, const char *realm)
|
|
{
|
|
struct ast_str *str = ast_str_alloca(256);
|
|
RAII_VAR(char *, eid, ao2_global_obj_ref(entity_id), ao2_cleanup);
|
|
char hash[33];
|
|
|
|
ast_str_append(&str, 0, "%s", timestamp);
|
|
ast_str_append(&str, 0, ":%s", rdata->pkt_info.src_name);
|
|
ast_str_append(&str, 0, ":%d", rdata->pkt_info.src_port);
|
|
ast_str_append(&str, 0, ":%s", eid);
|
|
ast_str_append(&str, 0, ":%s", realm);
|
|
ast_md5_hash(hash, ast_str_buffer(str));
|
|
|
|
ast_str_append(nonce, 0, "%s/%s", timestamp, hash);
|
|
return 0;
|
|
}
|
|
|
|
/*!
|
|
* \brief Ensure that a nonce on an incoming request is sane.
|
|
*
|
|
* The nonce in an incoming Authorization header needs to pass some scrutiny in order
|
|
* for us to consider accepting it. What we do is re-build a nonce based on request
|
|
* data and a realm and see if it matches the nonce they sent us.
|
|
* \param candidate The nonce on an incoming request
|
|
* \param rdata The incoming request
|
|
* \param auth The auth credentials we are trying to match against.
|
|
* \retval 0 Nonce does not pass validity checks
|
|
* \retval 1 Nonce passes validity check
|
|
*/
|
|
static int check_nonce(const char *candidate, const pjsip_rx_data *rdata, const struct ast_sip_auth *auth)
|
|
{
|
|
char *copy = ast_strdupa(candidate);
|
|
char *timestamp = strsep(©, "/");
|
|
int timestamp_int;
|
|
time_t now = time(NULL);
|
|
struct ast_str *calculated = ast_str_alloca(64);
|
|
|
|
if (!copy) {
|
|
/* Clearly a bad nonce! */
|
|
return 0;
|
|
}
|
|
|
|
if (sscanf(timestamp, "%30d", ×tamp_int) != 1) {
|
|
return 0;
|
|
}
|
|
|
|
if ((int) now - timestamp_int > auth->nonce_lifetime) {
|
|
return 0;
|
|
}
|
|
|
|
build_nonce(&calculated, timestamp, rdata, auth->realm);
|
|
ast_debug(3, "Calculated nonce %s. Actual nonce is %s\n", ast_str_buffer(calculated), candidate);
|
|
if (strcmp(ast_str_buffer(calculated), candidate)) {
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static int find_challenge(const pjsip_rx_data *rdata, const struct ast_sip_auth *auth)
|
|
{
|
|
struct pjsip_authorization_hdr *auth_hdr = (pjsip_authorization_hdr *) &rdata->msg_info.msg->hdr;
|
|
int challenge_found = 0;
|
|
char nonce[64];
|
|
|
|
while ((auth_hdr = (pjsip_authorization_hdr *) pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_AUTHORIZATION, auth_hdr->next))) {
|
|
ast_copy_pj_str(nonce, &auth_hdr->credential.digest.nonce, sizeof(nonce));
|
|
if (check_nonce(nonce, rdata, auth) && !pj_strcmp2(&auth_hdr->credential.digest.realm, auth->realm)) {
|
|
challenge_found = 1;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return challenge_found;
|
|
}
|
|
|
|
/*!
|
|
* \brief Common code for initializing a pjsip_auth_srv
|
|
*/
|
|
static void setup_auth_srv(pj_pool_t *pool, pjsip_auth_srv *auth_server, const char *realm)
|
|
{
|
|
pj_str_t realm_str;
|
|
pj_cstr(&realm_str, realm);
|
|
|
|
pjsip_auth_srv_init(pool, auth_server, &realm_str, digest_lookup, 0);
|
|
}
|
|
|
|
/*!
|
|
* \brief Result of digest verification
|
|
*/
|
|
enum digest_verify_result {
|
|
/*! Authentication credentials incorrect */
|
|
AUTH_FAIL,
|
|
/*! Authentication credentials correct */
|
|
AUTH_SUCCESS,
|
|
/*! Authentication credentials correct but nonce mismatch */
|
|
AUTH_STALE,
|
|
/*! Authentication credentials were not provided */
|
|
AUTH_NOAUTH,
|
|
};
|
|
|
|
/*!
|
|
* \brief astobj2 callback for verifying incoming credentials
|
|
*
|
|
* \param auth The ast_sip_auth to check against
|
|
* \param rdata The incoming request
|
|
* \param pool A pool to use for the auth server
|
|
* \return CMP_MATCH on successful authentication
|
|
* \return 0 on failed authentication
|
|
*/
|
|
static int verify(struct ast_sip_auth *auth, pjsip_rx_data *rdata, pj_pool_t *pool)
|
|
{
|
|
pj_status_t authed;
|
|
int response_code;
|
|
pjsip_auth_srv auth_server;
|
|
int stale = 0;
|
|
|
|
if (!find_challenge(rdata, auth)) {
|
|
/* Couldn't find a challenge with a sane nonce.
|
|
* Nonce mismatch may just be due to staleness.
|
|
*/
|
|
stale = 1;
|
|
}
|
|
|
|
setup_auth_srv(pool, &auth_server, auth->realm);
|
|
|
|
store_auth(auth);
|
|
|
|
authed = pjsip_auth_srv_verify(&auth_server, rdata, &response_code);
|
|
|
|
remove_auth();
|
|
|
|
if (authed == PJ_SUCCESS) {
|
|
if (stale) {
|
|
return AUTH_STALE;
|
|
} else {
|
|
return AUTH_SUCCESS;
|
|
}
|
|
}
|
|
|
|
if (authed == PJSIP_EAUTHNOAUTH) {
|
|
return AUTH_NOAUTH;
|
|
}
|
|
|
|
return AUTH_FAIL;
|
|
}
|
|
|
|
/*!
|
|
* \brief astobj2 callback for adding digest challenges to responses
|
|
*
|
|
* \param realm An auth's realm to build a challenge from
|
|
* \param tdata The response to add the challenge to
|
|
* \param rdata The request the challenge is in response to
|
|
* \param is_stale Indicates whether nonce on incoming request was stale
|
|
*/
|
|
static void challenge(const char *realm, pjsip_tx_data *tdata, const pjsip_rx_data *rdata, int is_stale)
|
|
{
|
|
pj_str_t qop;
|
|
pj_str_t pj_nonce;
|
|
pjsip_auth_srv auth_server;
|
|
struct ast_str *nonce = ast_str_alloca(256);
|
|
char time_buf[32];
|
|
time_t timestamp = time(NULL);
|
|
snprintf(time_buf, sizeof(time_buf), "%d", (int) timestamp);
|
|
|
|
build_nonce(&nonce, time_buf, rdata, realm);
|
|
|
|
setup_auth_srv(tdata->pool, &auth_server, realm);
|
|
|
|
pj_cstr(&pj_nonce, ast_str_buffer(nonce));
|
|
pj_cstr(&qop, "auth");
|
|
pjsip_auth_srv_challenge(&auth_server, &qop, &pj_nonce, NULL, is_stale ? PJ_TRUE : PJ_FALSE, tdata);
|
|
}
|
|
|
|
/*!
|
|
* \brief Check authentication using Digest scheme
|
|
*
|
|
* This function will check an incoming message against configured authentication
|
|
* options. If \b any of the incoming Authorization headers result in successful
|
|
* authentication, then authentication is considered successful.
|
|
*
|
|
* \see ast_sip_check_authentication
|
|
*/
|
|
static enum ast_sip_check_auth_result digest_check_auth(struct ast_sip_endpoint *endpoint,
|
|
pjsip_rx_data *rdata, pjsip_tx_data *tdata)
|
|
{
|
|
struct ast_sip_auth **auths;
|
|
enum digest_verify_result *verify_res;
|
|
enum ast_sip_check_auth_result res;
|
|
int i;
|
|
int failures = 0;
|
|
size_t auth_size;
|
|
|
|
RAII_VAR(struct ast_sip_endpoint *, artificial_endpoint,
|
|
ast_sip_get_artificial_endpoint(), ao2_cleanup);
|
|
|
|
auth_size = AST_VECTOR_SIZE(&endpoint->inbound_auths);
|
|
|
|
auths = ast_alloca(auth_size * sizeof(*auths));
|
|
verify_res = ast_alloca(auth_size * sizeof(*verify_res));
|
|
|
|
if (!auths) {
|
|
return AST_SIP_AUTHENTICATION_ERROR;
|
|
}
|
|
|
|
if (endpoint == artificial_endpoint) {
|
|
auths[0] = ast_sip_get_artificial_auth();
|
|
} else if (ast_sip_retrieve_auths(&endpoint->inbound_auths, auths)) {
|
|
res = AST_SIP_AUTHENTICATION_ERROR;
|
|
goto cleanup;
|
|
}
|
|
|
|
for (i = 0; i < auth_size; ++i) {
|
|
if (ast_strlen_zero(auths[i]->realm)) {
|
|
ast_string_field_set(auths[i], realm, "asterisk");
|
|
}
|
|
verify_res[i] = verify(auths[i], rdata, tdata->pool);
|
|
if (verify_res[i] == AUTH_SUCCESS) {
|
|
res = AST_SIP_AUTHENTICATION_SUCCESS;
|
|
goto cleanup;
|
|
}
|
|
if (verify_res[i] == AUTH_FAIL) {
|
|
failures++;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < auth_size; ++i) {
|
|
challenge(auths[i]->realm, tdata, rdata, verify_res[i] == AUTH_STALE);
|
|
}
|
|
|
|
if (failures == auth_size) {
|
|
res = AST_SIP_AUTHENTICATION_FAILED;
|
|
} else {
|
|
res = AST_SIP_AUTHENTICATION_CHALLENGE;
|
|
}
|
|
|
|
cleanup:
|
|
ast_sip_cleanup_auths(auths, auth_size);
|
|
return res;
|
|
}
|
|
|
|
static struct ast_sip_authenticator digest_authenticator = {
|
|
.requires_authentication = digest_requires_authentication,
|
|
.check_authentication = digest_check_auth,
|
|
};
|
|
|
|
static int build_entity_id(void)
|
|
{
|
|
RAII_VAR(struct ast_uuid *, uu, ast_uuid_generate(), ast_free_ptr);
|
|
RAII_VAR(char *, eid, ao2_alloc(AST_UUID_STR_LEN, NULL), ao2_cleanup);
|
|
|
|
if (!uu || !eid) {
|
|
return -1;
|
|
}
|
|
|
|
ast_uuid_to_str(uu, eid, AST_UUID_STR_LEN);
|
|
ao2_global_obj_replace_unref(entity_id, eid);
|
|
return 0;
|
|
}
|
|
|
|
static int reload_module(void)
|
|
{
|
|
if (build_entity_id()) {
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int load_module(void)
|
|
{
|
|
if (build_entity_id()) {
|
|
return AST_MODULE_LOAD_DECLINE;
|
|
}
|
|
if (ast_sip_register_authenticator(&digest_authenticator)) {
|
|
ao2_global_obj_release(entity_id);
|
|
return AST_MODULE_LOAD_DECLINE;
|
|
}
|
|
return AST_MODULE_LOAD_SUCCESS;
|
|
}
|
|
|
|
static int unload_module(void)
|
|
{
|
|
ast_sip_unregister_authenticator(&digest_authenticator);
|
|
ao2_global_obj_release(entity_id);
|
|
return 0;
|
|
}
|
|
|
|
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP authentication resource",
|
|
.support_level = AST_MODULE_SUPPORT_CORE,
|
|
.load = load_module,
|
|
.unload = unload_module,
|
|
.reload = reload_module,
|
|
.load_pri = AST_MODPRI_CHANNEL_DEPEND,
|
|
);
|