asterisk/res/res_pjsip_outbound_authenti...

604 lines
20 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.
*/
/*** MODULEINFO
<depend>pjproject</depend>
<depend>res_pjsip</depend>
<support_level>core</support_level>
***/
#include "asterisk.h"
#include <pjsip.h>
#include "asterisk/res_pjsip.h"
#include "asterisk/logger.h"
#include "asterisk/module.h"
#include "asterisk/strings.h"
#include "asterisk/vector.h"
pj_str_t supported_digest_algorithms[] = {
{ "MD5", 3}
};
/*!
* \internal
* \brief Determine proper authenticate header
*
* We need to search for different headers depending on whether
* the response code from the UAS/Proxy was 401 or 407.
*/
static pjsip_hdr_e get_auth_search_type(pjsip_rx_data *challenge)
{
if (challenge->msg_info.msg->line.status.code == PJSIP_SC_UNAUTHORIZED) {
return PJSIP_H_WWW_AUTHENTICATE;
} else if (challenge->msg_info.msg->line.status.code == PJSIP_SC_PROXY_AUTHENTICATION_REQUIRED) {
return PJSIP_H_PROXY_AUTHENTICATE;
} else {
ast_log(LOG_ERROR,
"Status code %d was received when it should have been 401 or 407.\n",
challenge->msg_info.msg->line.status.code);
return PJSIP_H_OTHER;
}
}
/*!
* \internal
* \brief Determine if digest algorithm in the header is one we support
*
* \retval 1 If we support the algorithm
* \retval 0 If we do not
*
*/
static int is_digest_algorithm_supported(pjsip_www_authenticate_hdr *auth_hdr)
{
int digest;
/* An empty digest is assumed to be md5 */
if (pj_strlen(&auth_hdr->challenge.digest.algorithm) == 0) {
return 1;
}
for (digest = 0; digest < ARRAY_LEN(supported_digest_algorithms); digest++) {
if (pj_stricmp(&auth_hdr->challenge.digest.algorithm, &supported_digest_algorithms[digest]) == 0) {
return 1;
}
}
return 0;
}
/*!
* \internal
* \brief Initialize pjproject with a valid set of credentials
*
* RFC7616 and RFC8760 allow more than one WWW-Authenticate or
* Proxy-Authenticate header per realm, each with different digest
* algorithms (including new ones like SHA-256 and SHA-512-256). However,
* thankfully, a UAS can NOT send back multiple Authenticate headers for
* the same realm with the same digest algorithm. The UAS is also
* supposed to send the headers in order of preference with the first one
* being the most preferred.
*
* We're supposed to send an Authorization header for the first one we
* encounter for a realm that we can support.
*
* The UAS can also send multiple realms, especially when it's a proxy
* that has forked the request in which case the proxy will aggregate all
* of the Authenticate and then them all back to the UAC.
*
* It doesn't stop there though... Each realm can require a different
* username from the others. There's also nothing preventing each digest
* algorithm from having a unique password although I'm not sure if
* that adds any benefit.
*
* So now... For each Authenticate header we encounter, we have to
* determine if we support the digest algorithm and, if not, just skip the
* header. We then have to find an auth object that matches the realm AND
* the digest algorithm or find a wildcard object that matches the digest
* algorithm. If we find one, we add it to the results vector and read the
* next Authenticate header. If the next header is for the same realm AND
* we already added an auth object for that realm, we skip the header.
* Otherwise we repeat the process for the next header.
*
* In the end, we'll have accumulated a list of credentials we can pass to
* pjproject that it can use to add Authentication headers to a request.
*
* \note: Neither we nor pjproject can currently handle digest algorithms
* other than MD5. We don't even have a place for it in the ast_sip_auth
* object. For this reason, we just skip processing any Authenticate
* header that's not MD5. When we support the others, we'll move the
* check into the loop that searches the objects.
*/
static pj_status_t set_outbound_authentication_credentials(pjsip_auth_clt_sess *auth_sess,
const struct ast_sip_auth_objects_vector *auth_objects_vector, pjsip_rx_data *challenge,
struct ast_str **realms)
{
int i;
size_t auth_object_count;
pjsip_www_authenticate_hdr *auth_hdr = NULL;
pj_status_t res = PJ_SUCCESS;
pjsip_hdr_e search_type;
size_t cred_count;
pjsip_cred_info *creds_array;
/*
* Normally vector elements are pointers to something else, usually
* structures. In this case however, the elements are the
* structures themselves instead of pointers to them. This is due
* to the fact that pjsip_auth_clt_set_credentials() expects an
* array of structures, not an array of pointers to structures.
* Thankfully, vectors allow you to "steal" their underlying
* arrays, in this case an array of pjsip_cred_info structures,
* which we'll pass to pjsip_auth_clt_set_credentials() at the
* end.
*/
AST_VECTOR(cred_info, pjsip_cred_info) auth_creds;
search_type = get_auth_search_type(challenge);
if (search_type == PJSIP_H_OTHER) {
/*
* The status code on the response wasn't 401 or 407
* so there are no WWW-Authenticate or Proxy-Authenticate
* headers to process.
*/
return PJ_ENOTSUP;
}
auth_object_count = AST_VECTOR_SIZE(auth_objects_vector);
if (auth_object_count == 0) {
/* This shouldn't happen but we'll check anyway. */
return PJ_EINVAL;
}
/*
* The number of pjsip_cred_infos we send to pjproject can
* vary based on the number of acceptable headers received
* and the number of acceptable auth objects on the endpoint
* so we just use a vector to accumulate them.
*
* NOTE: You have to call AST_VECTOR_FREE() on the vector
* but you don't have to free the elements because they're
* actual structures, not pointers to structures.
*/
if (AST_VECTOR_INIT(&auth_creds, 5) != 0) {
return PJ_ENOMEM;
}
/*
* It's going to be rare that we actually have more than one
* WWW-Authentication header or more than one auth object to
* match to it so the following nested loop should be fine.
*/
while ((auth_hdr = pjsip_msg_find_hdr(challenge->msg_info.msg,
search_type, auth_hdr ? auth_hdr->next : NULL))) {
int exact_match_index = -1;
int wildcard_match_index = -1;
int match_index = 0;
pjsip_cred_info auth_cred;
struct ast_sip_auth *auth = NULL;
memset(&auth_cred, 0, sizeof(auth_cred));
/*
* Since we only support the MD5 algorithm at the current time,
* there's no sense searching for auth objects that match the algorithm.
* In fact, the auth_object structure doesn't even have a member
* for it.
*
* When we do support more algorithms, this check will need to be
* moved inside the auth object loop below.
*
* Note: The header may not have specified an algorithm at all in which
* case it's assumed to be MD5. is_digest_algorithm_supported() returns
* true for that case.
*/
if (!is_digest_algorithm_supported(auth_hdr)) {
ast_debug(3, "Skipping header with realm '%.*s' and unsupported '%.*s' algorithm \n",
(int)auth_hdr->challenge.digest.realm.slen, auth_hdr->challenge.digest.realm.ptr,
(int)auth_hdr->challenge.digest.algorithm.slen, auth_hdr->challenge.digest.algorithm.ptr);
continue;
}
/*
* Appending the realms is strictly so digest_create_request_with_auth()
* can display good error messages. Since we only support one algorithm,
* there can't be more than one header with the same realm. No need to worry
* about duplicate realms until then.
*/
if (*realms) {
ast_str_append(realms, 0, "%.*s, ",
(int)auth_hdr->challenge.digest.realm.slen, auth_hdr->challenge.digest.realm.ptr);
}
ast_debug(3, "Searching auths to find matching ones for header with realm '%.*s' and algorithm '%.*s'\n",
(int)auth_hdr->challenge.digest.realm.slen, auth_hdr->challenge.digest.realm.ptr,
(int)auth_hdr->challenge.digest.algorithm.slen, auth_hdr->challenge.digest.algorithm.ptr);
/*
* Now that we have a valid header, we can loop over the auths available to
* find either an exact realm match or, failing that, a wildcard auth (an
* auth with an empty or "*" realm).
*
* NOTE: We never use the global default realm when we're the UAC responding
* to a 401 or 407. We only use that when we're the UAS (handled elsewhere)
* and the auth object didn't have a realm.
*/
for (i = 0; i < auth_object_count; ++i) {
auth = AST_VECTOR_GET(auth_objects_vector, i);
/*
* If this auth object's realm exactly matches the one
* from the header, we can just break out and use it.
*
* NOTE: If there's more than one auth object for an endpoint with
* a matching realm it's a misconfiguration. We'll only use the first.
*/
if (pj_stricmp2(&auth_hdr->challenge.digest.realm, auth->realm) == 0) {
ast_debug(3, "Found matching auth '%s' with realm '%s'\n", ast_sorcery_object_get_id(auth),
auth->realm);
exact_match_index = i;
/*
* If we found an exact realm match, there's no need to keep
* looking for a wildcard.
*/
break;
}
/*
* If this auth object's realm is empty or a "*", it's a wildcard
* auth object. We going to save its index but keep iterating over
* the vector in case we find an exact match later.
*
* NOTE: If there's more than one wildcard auth object for an endpoint
* it's a misconfiguration. We'll only use the first.
*/
if (wildcard_match_index < 0
&& (ast_strlen_zero(auth->realm) || ast_strings_equal(auth->realm, "*"))) {
ast_debug(3, "Found wildcard auth '%s' for realm '%.*s'\n", ast_sorcery_object_get_id(auth),
(int)auth_hdr->challenge.digest.realm.slen, auth_hdr->challenge.digest.realm.ptr);
wildcard_match_index = i;
}
}
if (exact_match_index < 0 && wildcard_match_index < 0) {
/*
* Didn't find either a wildcard or an exact realm match.
* Move on to the next header.
*/
ast_debug(3, "No auth matching realm or no wildcard found for realm '%.*s'\n",
(int)auth_hdr->challenge.digest.realm.slen, auth_hdr->challenge.digest.realm.ptr);
continue;
}
if (exact_match_index >= 0) {
/*
* If we found an exact match, we'll always prefer that.
*/
match_index = exact_match_index;
auth = AST_VECTOR_GET(auth_objects_vector, match_index);
ast_debug(3, "Using matched auth '%s' with realm '%.*s'\n", ast_sorcery_object_get_id(auth),
(int)auth_hdr->challenge.digest.realm.slen, auth_hdr->challenge.digest.realm.ptr);
} else {
/*
* We'll only use the wildcard if we didn't find an exact match.
*/
match_index = wildcard_match_index;
auth = AST_VECTOR_GET(auth_objects_vector, match_index);
ast_debug(3, "Using wildcard auth '%s' for realm '%.*s'\n", ast_sorcery_object_get_id(auth),
(int)auth_hdr->challenge.digest.realm.slen, auth_hdr->challenge.digest.realm.ptr);
}
/*
* Copy the fields from the auth_object to the
* pjsip_cred_info structure.
*/
auth_cred.realm = auth_hdr->challenge.common.realm;
pj_cstr(&auth_cred.username, auth->auth_user);
pj_cstr(&auth_cred.scheme, "digest");
switch (auth->type) {
case AST_SIP_AUTH_TYPE_USER_PASS:
pj_cstr(&auth_cred.data, auth->auth_pass);
auth_cred.data_type = PJSIP_CRED_DATA_PLAIN_PASSWD;
break;
case AST_SIP_AUTH_TYPE_MD5:
pj_cstr(&auth_cred.data, auth->md5_creds);
auth_cred.data_type = PJSIP_CRED_DATA_DIGEST;
break;
case AST_SIP_AUTH_TYPE_GOOGLE_OAUTH:
/* nothing to do. handled seperately in res_pjsip_outbound_registration */
break;
case AST_SIP_AUTH_TYPE_ARTIFICIAL:
ast_log(LOG_ERROR,
"Trying to set artificial outbound auth credentials shouldn't happen.\n");
continue;
} /* End auth object loop */
/*
* Because the vector contains actual structures and not pointers
* to structures, the call to AST_VECTOR_APPEND results in a simple
* assign of one structure to another, effectively copying the auth_cred
* structure contents to the array element.
*
* Also note that the calls to pj_cstr above set their respective
* auth_cred fields to the _pointers_ of their corresponding auth
* object fields. This is safe because the call to
* pjsip_auth_clt_set_credentials() below strdups them before we
* return to the calling function which decrements the reference
* counts.
*/
res = AST_VECTOR_APPEND(&auth_creds, auth_cred);
if (res != PJ_SUCCESS) {
res = PJ_ENOMEM;
goto cleanup;
}
} /* End header loop */
if (*realms && ast_str_strlen(*realms)) {
/*
* Again, this is strictly so digest_create_request_with_auth()
* can display good error messages.
*
* Chop off the trailing ", " on the last realm.
*/
ast_str_truncate(*realms, ast_str_strlen(*realms) - 2);
}
if (AST_VECTOR_SIZE(&auth_creds) == 0) {
/* No matching auth objects were found. */
res = PJSIP_ENOCREDENTIAL;
goto cleanup;
}
/*
* Here's where we steal the cred info structures from the vector.
*
* The steal effectively returns a pointer to the underlying
* array of pjsip_cred_info structures which is exactly what we need
* to pass to pjsip_auth_clt_set_credentials().
*
* <struct cred info><struct cred info>...<struct cred info>
* ^pointer
*
* Since we stole the array from the vector, we have to free it ourselves.
*
* We also have to copy the size before we steal because stealing
* resets the vector size to 0.
*/
cred_count = AST_VECTOR_SIZE(&auth_creds);
creds_array = AST_VECTOR_STEAL_ELEMENTS(&auth_creds);
res = pjsip_auth_clt_set_credentials(auth_sess, cred_count, creds_array);
ast_free(creds_array);
if (res == PJ_SUCCESS) {
ast_debug(3, "Set %"PRIu64" credentials in auth session\n", cred_count);
} else {
ast_log(LOG_ERROR, "Failed to set %"PRIu64" credentials in auth session\n", cred_count);
}
cleanup:
AST_VECTOR_FREE(&auth_creds);
return res;
}
/*!
* \internal
* \brief Create new tdata with auth based on original tdata
* \param auth_ids_vector Vector of auth IDs retrieved from endpoint
* \param challenge rdata of the response from the UAS with challenge
* \param old_request tdata from the original request
* \param new_request tdata of the new request with the auth
*
* This function is what's registered with ast_sip_register_outbound_authenticator()
*
* \retval 0 success
* \retval -1 failure
*/
static int digest_create_request_with_auth(const struct ast_sip_auth_vector *auth_ids_vector,
pjsip_rx_data *challenge, pjsip_tx_data *old_request, pjsip_tx_data **new_request)
{
pjsip_auth_clt_sess auth_sess;
pjsip_cseq_hdr *cseq;
pj_status_t status;
struct ast_sip_auth_objects_vector auth_objects_vector;
size_t auth_object_count = 0;
struct ast_sip_endpoint *endpoint;
char *id = NULL;
const char *id_type;
struct ast_str *realms = NULL;
pjsip_dialog *dlg;
int res = -1;
/*
* Some older compilers have an issue with initializing structures with
* pjsip_auth_clt_sess auth_sess = { 0, };
* so we'll just do it the old fashioned way.
*/
memset(&auth_sess, 0, sizeof(auth_sess));
dlg = pjsip_rdata_get_dlg(challenge);
if (dlg) {
/* The only thing we use endpoint for is to get an id for error/debug messages */
endpoint = ast_sip_dialog_get_endpoint(dlg);
id = endpoint ? ast_strdupa(ast_sorcery_object_get_id(endpoint)) : NULL;
ao2_cleanup(endpoint);
id_type = "Endpoint";
}
/* If there was no dialog, then this is probably a REGISTER so no endpoint */
if (!id) {
/* The only thing we use the address for is to get an id for error/debug messages */
id = ast_alloca(AST_SOCKADDR_BUFLEN);
pj_sockaddr_print(&challenge->pkt_info.src_addr, id, AST_SOCKADDR_BUFLEN, 3);
id_type = "Host";
}
if (!auth_ids_vector || AST_VECTOR_SIZE(auth_ids_vector) == 0) {
ast_log(LOG_ERROR, "%s: '%s': There were no auth ids available\n", id_type, id);
return -1;
}
if (AST_VECTOR_INIT(&auth_objects_vector, AST_VECTOR_SIZE(auth_ids_vector)) != 0) {
ast_log(LOG_ERROR, "%s: '%s': Couldn't initialize auth object vector\n", id_type, id);
return -1;
}
/*
* We don't really care about ast_sip_retrieve_auths_vector()'s return code
* because we're checking the count of objects in the vector.
*
* Don't forget to call
* ast_sip_cleanup_auth_objects_vector(&auth_objects_vector);
* AST_VECTOR_FREE(&auth_objects_vector);
* when you're done with the vector
*/
ast_sip_retrieve_auths_vector(auth_ids_vector, &auth_objects_vector);
auth_object_count = AST_VECTOR_SIZE(&auth_objects_vector);
if (auth_object_count == 0) {
/*
* If none of the auth ids were found, we can't continue.
* We're OK if there's at least one left.
* ast_sip_retrieve_auths_vector() will print a warning for every
* id that wasn't found.
*/
res = -1;
goto cleanup;
}
if (pjsip_auth_clt_init(&auth_sess, ast_sip_get_pjsip_endpoint(),
old_request->pool, 0) != PJ_SUCCESS) {
ast_log(LOG_ERROR, "%s: '%s': Failed to initialize client authentication session\n",
id_type, id);
res = -1;
goto cleanup;
}
/*
* realms is used only for displaying good error messages.
*/
realms = ast_str_create(32);
if (!realms) {
res = -1;
goto cleanup;
}
/*
* Load pjproject with the valid credentials for the Authentication headers
* received on the 401 or 407 response.
*/
status = set_outbound_authentication_credentials(&auth_sess, &auth_objects_vector, challenge, &realms);
switch (status) {
case PJ_SUCCESS:
break;
case PJSIP_ENOCREDENTIAL:
ast_log(LOG_WARNING,
"%s: '%s': No auth objects matching realm(s) '%s' from challenge found.\n", id_type, id,
realms ? ast_str_buffer(realms) : "<none>");
res = -1;
goto cleanup;
default:
ast_log(LOG_WARNING, "%s: '%s': Failed to set authentication credentials\n", id_type, id);
res = -1;
goto cleanup;
}
/*
* reinit_req actually creates the Authorization headers to send on
* the next request. If reinit_req already has a cached credential
* from an earlier successful authorization, it'll use it. Otherwise
* it'll create a new authorization and cache it.
*/
status = pjsip_auth_clt_reinit_req(&auth_sess, challenge, old_request, new_request);
switch (status) {
case PJ_SUCCESS:
/* PJSIP creates a new transaction for new_request (meaning it creates a new
* branch). However, it recycles the Call-ID, from-tag, and CSeq from the
* original request. Some SIP implementations will not process the new request
* since the CSeq is the same as the original request. Incrementing it here
* fixes the interop issue
*/
cseq = pjsip_msg_find_hdr((*new_request)->msg, PJSIP_H_CSEQ, NULL);
ast_assert(cseq != NULL);
++cseq->cseq;
res = 0;
goto cleanup;
case PJSIP_ENOCREDENTIAL:
/*
* This should be rare since set_outbound_authentication_credentials()
* did the matching but you never know.
*/
ast_log(LOG_WARNING,
"%s: '%s': No auth objects matching realm(s) '%s' from challenge found.\n", id_type, id,
realms ? ast_str_buffer(realms) : "<none>");
break;
case PJSIP_EAUTHSTALECOUNT:
ast_log(LOG_WARNING,
"%s: '%s': Unable to create request with auth. Number of stale retries exceeded.\n",
id_type, id);
break;
case PJSIP_EFAILEDCREDENTIAL:
ast_log(LOG_WARNING, "%s: '%s': Authentication credentials not accepted by server.\n",
id_type, id);
break;
default:
ast_log(LOG_WARNING, "%s: '%s': Unable to create request with auth. Unknown failure.\n",
id_type, id);
break;
}
res = -1;
cleanup:
#if defined(HAVE_PJSIP_AUTH_CLT_DEINIT)
/* If we initialized the auth_sess, clean it up */
if (auth_sess.endpt) {
pjsip_auth_clt_deinit(&auth_sess);
}
#endif
ast_sip_cleanup_auth_objects_vector(&auth_objects_vector);
AST_VECTOR_FREE(&auth_objects_vector);
ast_free(realms);
return res;
}
static struct ast_sip_outbound_authenticator digest_authenticator = {
.create_request_with_auth = digest_create_request_with_auth,
};
static int load_module(void)
{
if (ast_sip_register_outbound_authenticator(&digest_authenticator)) {
return AST_MODULE_LOAD_DECLINE;
}
return AST_MODULE_LOAD_SUCCESS;
}
static int unload_module(void)
{
ast_sip_unregister_outbound_authenticator(&digest_authenticator);
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,
.load_pri = AST_MODPRI_CHANNEL_DEPEND,
.requires = "res_pjsip",
);