res_fax: Fix reference leak caused by gateway sessions

Fax gateway session objects can be re-used, causing the
same gateway session to be added to faxregistry.container
more than once.  This change causes fax_session_new to
remove the reserved session from the container before
it's id is changed, ensuring it's possible for the
session to be freed.

ASTERISK-24392 #close
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/4049/
........

Merged revisions 425457 from http://svn.asterisk.org/svn/asterisk/branches/11

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/12@425458 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/res/res_fax.c b/res/res_fax.c
index 8ec0e0896d7080f4d17a9fe5e2f822dcf5b6d9ad..4e58e89ab40e5d158ad97c38877ccba01381fe5d 100644 (file)
--- a/res/res_fax.c
+++ b/res/res_fax.c
@@ -1032,6 +1032,7 @@ static struct ast_fax_session *fax_session_new(struct ast_fax_session_details *d
        if (reserved) {
                s = reserved;
                ao2_ref(reserved, +1);
+               ao2_unlink(faxregistry.container, reserved);
 
                /* NOTE: we don't consume the reference to the reserved
                 * session. The session returned from fax_session_new() is a