Avoid injection using quotes after `auth` command;

Added non-greedy fallback for quoted something (with lookahead simulated possessive greedy catch of non-quoted parts `[^"]*(?=")`).
Note that because host-info's are hereafter (with foreign input in-between), we would not use greedy or non-greedy catch-alls (`.*` or `.*?`) here (preventing performance losses).

config/filter.d/exim.conf

@@ -18,7 +18,7 @@ failregex = ^%(pid)s %(host_info)ssender verify fail for <\S+>: (?:Unknown user|
             ^%(pid)s %(host_info)srejected RCPT [^@]+@\S+: (?:relay not permitted|Sender verify failed|Unknown user|Unrouteable address)\s*$
             ^%(pid)s SMTP protocol synchronization error \([^)]*\): rejected (?:connection from|"\S+") %(host_info)s(?:next )?input=".*"\s*$
             ^%(pid)s SMTP call from \S+ %(host_info)sdropped: too many nonmail commands \(last was "\S+"\)\s*$
-            ^%(pid)s SMTP protocol error in "[^"]+" %(host_info)sAUTH command used when not advertised\s*$
+            ^%(pid)s SMTP protocol error in "[^"]+(?:"+[^"]*(?="))*?" %(host_info)sAUTH command used when not advertised\s*$
             ^%(pid)s no MAIL in SMTP connection from (?:[^\[\( ]* )?(?:\(\S*\) )?%(host_info)sD=\d\S*s(?: C=\S*)?\s*$
             ^%(pid)s (?:[\w\-]+ )?SMTP connection from (?:[^\[\( ]* )?(?:\(\S*\) )?%(host_info)sclosed by DROP in ACL\s*$