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asterisk/channels/sip/security_events.c
Matthew Jordan 0ffce56f1b AST-2013-003: Prevent username disclosure in SIP channel driver 
When authenticating a SIP request with alwaysauthreject enabled, allowguest
disabled, and autocreatepeer disabled, Asterisk discloses whether a user
exists for INVITE, SUBSCRIBE, and REGISTER transactions in multiple ways. The
information is disclosed when:
 * A "407 Proxy Authentication Required" response is sent instead of a
   "401 Unauthorized" response
 * The presence or absence of additional tags occurs at the end of "403
   Forbidden" (such as "(Bad Auth)")
 * A "401 Unauthorized" response is sent instead of "403 Forbidden" response
   after a retransmission
 * Retransmission are sent when a matching peer did not exist, but not when a
   matching peer did exist.

This patch resolves these various vectors by ensuring that the responses sent
in all scenarios is the same, regardless of the presence of a matching peer.

This issue was reported by Walter Doekes, OSSO B.V. A substantial portion of
the testing and the solution to this problem was done by Walter as well - a
huge thanks to his tireless efforts in finding all the ways in which this
setting didn't work, providing automated tests, and working with Kinsey on
getting this fixed.

(closes issue ASTERISK-21013)
Reported by: wdoekes
Tested by: wdoekes, kmoore
patches:
  AST-2013-003-1.8 uploaded by kmoore, wdoekes (License 6273, 5674)
  AST-2013-003-10 uploaded by kmoore, wdoekes (License 6273, 5674)
  AST-2013-003-11 uploaded by kmoore, wdoekes (License 6273, 5674)
........

Merged revisions 384003 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@384019 65c4cc65-6c06-0410-ace0-fbb531ad65f3
2013-03-27 15:27:31 +00:00

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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2012, Digium, Inc.
*
* Michael L. Young <elgueromexicano@gmail.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.
*/
/*!
* \file
*
* \brief Generate security events in the SIP channel
*
* \author Michael L. Young <elgueromexicano@gmail.com>
*/
/*** MODULEINFO
<support_level>core</support_level>
***/
#include "asterisk.h"
ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
/* #define REF_DEBUG 1 */
#include "include/sip.h"
#include "include/security_events.h"
/*! \brief Determine transport type used to receive request*/
static enum ast_security_event_transport_type security_event_get_transport(const struct sip_pvt *p)
{
int res = 0;
switch (p->socket.type) {
case SIP_TRANSPORT_UDP:
return AST_SECURITY_EVENT_TRANSPORT_UDP;
case SIP_TRANSPORT_TCP:
case SIP_TRANSPORT_WS:
return AST_SECURITY_EVENT_TRANSPORT_TCP;
case SIP_TRANSPORT_TLS:
case SIP_TRANSPORT_WSS:
return AST_SECURITY_EVENT_TRANSPORT_TLS;
}
return res;
}
void sip_report_invalid_peer(const struct sip_pvt *p)
{
char session_id[32];
struct ast_security_event_inval_acct_id inval_acct_id = {
.common.event_type = AST_SECURITY_EVENT_INVAL_ACCT_ID,
.common.version = AST_SECURITY_EVENT_INVAL_ACCT_ID_VERSION,
.common.service = "SIP",
.common.account_id = p->exten,
.common.local_addr = {
.addr = &p->ourip,
.transport = security_event_get_transport(p)
},
.common.remote_addr = {
.addr = &p->sa,
.transport = security_event_get_transport(p)
},
.common.session_id = session_id,
};
snprintf(session_id, sizeof(session_id), "%p", p);
ast_security_event_report(AST_SEC_EVT(&inval_acct_id));
}
void sip_report_failed_acl(const struct sip_pvt *p, const char *aclname)
{
char session_id[32];
struct ast_security_event_failed_acl failed_acl_event = {
.common.event_type = AST_SECURITY_EVENT_FAILED_ACL,
.common.version = AST_SECURITY_EVENT_FAILED_ACL_VERSION,
.common.service = "SIP",
.common.account_id = p->exten,
.common.local_addr = {
.addr = &p->ourip,
.transport = security_event_get_transport(p)
},
.common.remote_addr = {
.addr = &p->sa,
.transport = security_event_get_transport(p)
},
.common.session_id = session_id,
.acl_name = aclname,
};
snprintf(session_id, sizeof(session_id), "%p", p);
ast_security_event_report(AST_SEC_EVT(&failed_acl_event));
}
void sip_report_inval_password(const struct sip_pvt *p, const char *response_challenge, const char *response_hash)
{
char session_id[32];
struct ast_security_event_inval_password inval_password = {
.common.event_type = AST_SECURITY_EVENT_INVAL_PASSWORD,
.common.version = AST_SECURITY_EVENT_INVAL_PASSWORD_VERSION,
.common.service = "SIP",
.common.account_id = p->exten,
.common.local_addr = {
.addr = &p->ourip,
.transport = security_event_get_transport(p)
},
.common.remote_addr = {
.addr = &p->sa,
.transport = security_event_get_transport(p)
},
.common.session_id = session_id,
.challenge = p->nonce,
.received_challenge = response_challenge,
.received_hash = response_hash,
};
snprintf(session_id, sizeof(session_id), "%p", p);
ast_security_event_report(AST_SEC_EVT(&inval_password));
}
void sip_report_auth_success(const struct sip_pvt *p, uint32_t *using_password)
{
char session_id[32];
struct ast_security_event_successful_auth successful_auth = {
.common.event_type = AST_SECURITY_EVENT_SUCCESSFUL_AUTH,
.common.version = AST_SECURITY_EVENT_SUCCESSFUL_AUTH_VERSION,
.common.service = "SIP",
.common.account_id = p->exten,
.common.local_addr = {
.addr = &p->ourip,
.transport = security_event_get_transport(p)
},
.common.remote_addr = {
.addr = &p->sa,
.transport = security_event_get_transport(p)
},
.common.session_id = session_id,
.using_password = using_password,
};
snprintf(session_id, sizeof(session_id), "%p", p);
ast_security_event_report(AST_SEC_EVT(&successful_auth));
}
void sip_report_session_limit(const struct sip_pvt *p)
{
char session_id[32];
struct ast_security_event_session_limit session_limit = {
.common.event_type = AST_SECURITY_EVENT_SESSION_LIMIT,
.common.version = AST_SECURITY_EVENT_SESSION_LIMIT_VERSION,
.common.service = "SIP",
.common.account_id = p->exten,
.common.local_addr = {
.addr = &p->ourip,
.transport = security_event_get_transport(p)
},
.common.remote_addr = {
.addr = &p->sa,
.transport = security_event_get_transport(p)
},
.common.session_id = session_id,
};
snprintf(session_id, sizeof(session_id), "%p", p);
ast_security_event_report(AST_SEC_EVT(&session_limit));
}
void sip_report_failed_challenge_response(const struct sip_pvt *p, const char *response, const char *expected_response)
{
char session_id[32];
char account_id[256];
struct ast_security_event_chal_resp_failed chal_resp_failed = {
.common.event_type = AST_SECURITY_EVENT_CHAL_RESP_FAILED,
.common.version = AST_SECURITY_EVENT_CHAL_RESP_FAILED_VERSION,
.common.service = "SIP",
.common.account_id = account_id,
.common.local_addr = {
.addr = &p->ourip,
.transport = security_event_get_transport(p)
},
.common.remote_addr = {
.addr = &p->sa,
.transport = security_event_get_transport(p)
},
.common.session_id = session_id,
.challenge = p->nonce,
.response = response,
.expected_response = expected_response,
};
if (!ast_strlen_zero(p->from)) { /* When dialing, show account making call */
ast_copy_string(account_id, p->from, sizeof(account_id));
} else {
ast_copy_string(account_id, p->exten, sizeof(account_id));
}
snprintf(session_id, sizeof(session_id), "%p", p);
ast_security_event_report(AST_SEC_EVT(&chal_resp_failed));
}
void sip_report_chal_sent(const struct sip_pvt *p)
{
char session_id[32];
char account_id[256];
struct ast_security_event_chal_sent chal_sent = {
.common.event_type = AST_SECURITY_EVENT_CHAL_SENT,
.common.version = AST_SECURITY_EVENT_CHAL_SENT_VERSION,
.common.service = "SIP",
.common.account_id = account_id,
.common.local_addr = {
.addr = &p->ourip,
.transport = security_event_get_transport(p)
},
.common.remote_addr = {
.addr = &p->sa,
.transport = security_event_get_transport(p)
},
.common.session_id = session_id,
.challenge = p->nonce,
};
if (!ast_strlen_zero(p->from)) { /* When dialing, show account making call */
ast_copy_string(account_id, p->from, sizeof(account_id));
} else {
ast_copy_string(account_id, p->exten, sizeof(account_id));
}
snprintf(session_id, sizeof(session_id), "%p", p);
ast_security_event_report(AST_SEC_EVT(&chal_sent));
}
void sip_report_inval_transport(const struct sip_pvt *p, const char *transport)
{
char session_id[32];
struct ast_security_event_inval_transport inval_transport = {
.common.event_type = AST_SECURITY_EVENT_INVAL_TRANSPORT,
.common.version = AST_SECURITY_EVENT_INVAL_TRANSPORT_VERSION,
.common.service = "SIP",
.common.account_id = p->exten,
.common.local_addr = {
.addr = &p->ourip,
.transport = security_event_get_transport(p)
},
.common.remote_addr = {
.addr = &p->sa,
.transport = security_event_get_transport(p)
},
.common.session_id = session_id,
.transport = transport,
};
snprintf(session_id, sizeof(session_id), "%p", p);
ast_security_event_report(AST_SEC_EVT(&inval_transport));
}
int sip_report_security_event(const struct sip_pvt *p, const struct sip_request *req, const int res) {
struct sip_peer *peer_report;
enum check_auth_result res_report = res;
struct ast_str *buf;
char *c;
const char *authtoken;
char *reqheader, *respheader;
int result = 0;
char aclname[256];
struct digestkeys keys[] = {
[K_RESP] = { "response=", "" },
[K_URI] = { "uri=", "" },
[K_USER] = { "username=", "" },
[K_NONCE] = { "nonce=", "" },
[K_LAST] = { NULL, NULL}
};
peer_report = sip_find_peer(p->exten, NULL, TRUE, FINDPEERS, FALSE, 0);
switch(res_report) {
case AUTH_DONT_KNOW:
break;
case AUTH_SUCCESSFUL:
if (peer_report) {
if (ast_strlen_zero(peer_report->secret) && ast_strlen_zero(peer_report->md5secret)) {
sip_report_auth_success(p, (uint32_t *) 0);
} else {
sip_report_auth_success(p, (uint32_t *) 1);
}
}
break;
case AUTH_CHALLENGE_SENT:
sip_report_chal_sent(p);
break;
case AUTH_SECRET_FAILED:
case AUTH_USERNAME_MISMATCH:
sip_auth_headers(WWW_AUTH, &respheader, &reqheader);
authtoken = sip_get_header(req, reqheader);
buf = ast_str_thread_get(&check_auth_buf, CHECK_AUTH_BUF_INITLEN);
ast_str_set(&buf, 0, "%s", authtoken);
c = buf->str;
sip_digest_parser(c, keys);
if (res_report == AUTH_SECRET_FAILED) {
sip_report_inval_password(p, keys[K_NONCE].s, keys[K_RESP].s);
} else {
if (peer_report) {
sip_report_failed_challenge_response(p, keys[K_USER].s, peer_report->username);
}
}
break;
case AUTH_NOT_FOUND:
/* with sip_cfg.alwaysauthreject on, generates 2 events */
sip_report_invalid_peer(p);
break;
case AUTH_UNKNOWN_DOMAIN:
snprintf(aclname, sizeof(aclname), "domain_must_match");
sip_report_failed_acl(p, aclname);
break;
case AUTH_PEER_NOT_DYNAMIC:
snprintf(aclname, sizeof(aclname), "peer_not_dynamic");
sip_report_failed_acl(p, aclname);
break;
case AUTH_ACL_FAILED:
/* with sip_cfg.alwaysauthreject on, generates 2 events */
snprintf(aclname, sizeof(aclname), "device_must_match_acl");
sip_report_failed_acl(p, aclname);
break;
case AUTH_BAD_TRANSPORT:
sip_report_inval_transport(p, sip_get_transport(req->socket.type));
break;
case AUTH_RTP_FAILED:
break;
case AUTH_SESSION_LIMIT:
sip_report_session_limit(p);
break;
}
if (peer_report) {
sip_unref_peer(peer_report, "sip_report_security_event: sip_unref_peer: from handle_incoming");
}
return result;
}
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