res_pjsip_registrar: Fix bad memory-ness with user_agent.

Recent changes to the PJSIP registrar resulted in tests failing due to
missing AOR_CONTACT_ADDED test events. The reason for this was that the
user_agent string had junk values in it, resulting in being unable to
generate the event.

I'm going to be honest here, I have no idea why this was happening. Here
are the steps needed for the user_agent variable to get messed up:
* REGISTER is received
* First contact in the REGISTER results in a contact being removed
* Second contact in the REGISTER results in a contact being added
* The contact, AOR, expiration, and user agent all have to be passed as
  format parameters to the creation of a string. Any subset of those
  parameters would not be enough to cause the problem.

Looking into what was happening, the thing that struck me as odd was
that the user_agent variable was meant to be set to the value of the
User-Agent SIP header in the incoming REGISTER. However, when removing a
contact, the user_agent variable would be set (via ast_strdupa inside a
loop) to the stored contact's user_agent. This means that the
user_agent's value would be incorrect when attempting to process further
contacts in the incoming REGISTER.

The fix here is to use a different variable for the stored user agent
when removing a contact. Correcting the behavior to be correct also
means the memory usage is less weird, and the issue no longer occurs.

ASTERISK-25929 #close
Reported by Joshua Colp

Change-Id: I7cd24c86a38dec69ebcc94150614bc25f46b8c08

diff --git a/res/res_pjsip_registrar.c b/res/res_pjsip_registrar.c
index a4a75bb7e5a1e26254cae4b193af623ab76ab42f..638330e16f8155ceb3dc6433310d385ce31e57ce 100644 (file)
--- a/res/res_pjsip_registrar.c
+++ b/res/res_pjsip_registrar.c
@@ -575,7 +575,6 @@ static int rx_task(void *data)
                        ao2_cleanup(contact_update);
                } else {
                        /* We want to report the user agent that was actually in the removed contact */
-                       user_agent = ast_strdupa(contact->user_agent);
                        ast_sip_location_delete_contact(contact);
                        ast_verb(3, "Removed contact '%s' from AOR '%s' due to request\n", contact_uri, aor_name);
                        ast_test_suite_event_notify("AOR_CONTACT_REMOVED",
@@ -584,7 +583,7 @@ static int rx_task(void *data)
                                        "UserAgent: %s",
                                        contact_uri,
                                        aor_name,
-                                       user_agent);
+                                       contact->user_agent);
                }
        }