res_pjsip: Add ability to identify by Authorization username

A feature of chan_sip that service providers relied upon was the ability to
identify by the Authorization username.  This is most often used when customers
have a PBX that needs to register rather than identify by IP address.  From my
own experiance, this is pretty common with small businesses who otherwise
don't need a static IP.

In this scenario, a register from the customer's PBX may succeed because From
will usually contain the PBXs account id but an INVITE will contain the caller
id.  With nothing recognizable in From, the service provider's Asterisk can
never match to an endpoint and the INVITE just stays unauthorized.

The fixes:

A new value "auth_username" has been added to endpoint/identify_by that
will use the username and digest fields in the Authorization header
instead of username and domain in the the From header to match an endpoint,
or the To header to match an aor.  This code as added to
res_pjsip_endpoint_identifier_user rather than creating a new module.

Although identify_by was always a comma-separated list, there was only
1 choice so order wasn't preserved.  So to keep the order, a vector was added
to the end of ast_sip_endpoint.  This is only used by res_pjsip_registrar
to find the aor.  The res_pjsip_endpoint_identifier_* modules are called in
globals/endpoint_identifier_order.

Along the way, the logic in res_pjsip_registrar was corrected to match
most-specific to least-specific as res_pjsip_endpoint_identifier_user does.

The order is:

username@domain
username@domain_alias
username

Auth by username does present 1 problem however, the first INVITE won't have
an Authorization header so the distributor, not finding a match on anything,
sends a securty_alert.  It still sends a 401 with a challenge so the next
INVITE will have the Authorization header and presumably succeed.  As a result
though, that first security alert is actually a false alarm.

To address this, a new feature has been added to pjsip_distributor that keeps
track of unidentified requests and only sends the security alert if a
configurable number of unidentified requests come from the same IP in a
configurable amout of time.  Those configuration options have been added to
the global config object.  This feature is only used when auth_username
is enabled.

Finally, default_realm was added to the globals object to replace the hard
coded "asterisk" used when an endpoint is not yet identified.

The testsuite tests all pass but new tests are forthcoming for this new
feature.

ASTERISK-25835 #close
Reported-by: Ross Beer

Change-Id: I30ba62d208e6f63439600916fcd1c08a365ed69d

1 files changed, 27 insertions, 0 deletions

diff --git a/include/asterisk/res_pjsip.h b/include/asterisk/res_pjsip.h
index 696074159..5ffeaff60 100644
--- a/include/asterisk/res_pjsip.h
+++ b/include/asterisk/res_pjsip.h
@@ -396,7 +396,10 @@ AST_VECTOR(ast_sip_auth_vector, const char *);
 enum ast_sip_endpoint_identifier_type {
 	/*! Identify based on user name in From header */
 	AST_SIP_ENDPOINT_IDENTIFY_BY_USERNAME = (1 << 0),
+	/*! Identify based on user name in Auth header first, then From header */
+	AST_SIP_ENDPOINT_IDENTIFY_BY_AUTH_USERNAME = (1 << 1),
 };
+AST_VECTOR(ast_sip_identify_by_vector, enum ast_sip_endpoint_identifier_type);
 
 enum ast_sip_session_refresh_method {
 	/*! Use reinvite to negotiate direct media */
@@ -708,6 +711,8 @@ struct ast_sip_endpoint {
 	enum ast_sip_dtmf_mode dtmf;
 	/*! Method(s) by which the endpoint should be identified. */
 	enum ast_sip_endpoint_identifier_type ident_method;
+	/*! Order of the method(s) by which the endpoint should be identified. */
+	struct ast_sip_identify_by_vector ident_method_order;
 	/*! Boolean indicating if ringing should be sent as inband progress */
 	unsigned int inband_progress;
 	/*! Pointer to the persistent Asterisk endpoint */
@@ -2454,6 +2459,18 @@ char *ast_sip_get_endpoint_identifier_order(void);
 char *ast_sip_get_default_voicemail_extension(void);
 
 /*!
+ * \brief Retrieve the global default realm.
+ *
+ * This is the value placed in outbound challenges' realm if there
+ * is no better option (such as an auth-configured realm).
+ *
+ * \param[out] realm The default realm
+ * \param size The buffer size of realm
+ * \return nothing
+ */
+void ast_sip_get_default_realm(char *realm, size_t size);
+
+/*!
  * \brief Retrieve the global default from user.
  *
  * This is the value placed in outbound requests' From header if there
@@ -2599,5 +2616,15 @@ int ast_sip_set_tpselector_from_transport_name(const char *transport_name, pjsip
 void ast_sip_modify_id_header(pj_pool_t *pool, pjsip_fromto_hdr *id_hdr,
 	const struct ast_party_id *id);
 
+/*!
+ * \brief Retrieve the unidentified request security event thresholds
+ * \since 13.8.0
+ *
+ * \param count The maximum number of unidentified requests per source ip to accumulate before emitting a security event
+ * \param period The period in seconds over which to accumulate unidentified requests
+ * \param prune_interval The interval in seconds at which expired entries will be pruned
+ */
+void ast_sip_get_unidentified_request_thresholds(unsigned int *count, unsigned int *period,
+	unsigned int *prune_interval);
 
 #endif /* _RES_PJSIP_H */