net/sctp: Prevent autoclose integer overflow in sctp_association_init()

While by default max_autoclose equals to INT_MAX / HZ, one may set
net.sctp.max_autoclose to UINT_MAX. There is code in
sctp_association_init() that can consequently trigger overflow.

Cc: [e-mail]
Fixes: 9f70f46bd4c7 ("sctp: properly latch and use autoclose value from sock to association")
Signed-off-by: Nikolay Kuratov <[e-mail]>
Acked-by: Xin Long <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/sctp/associola.c

···
 		= 5 * asoc->rto_max;
 
 	asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
-	asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sp->autoclose * HZ;
+	asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
+		(unsigned long)sp->autoclose * HZ;
 
 	/* Initializes the timers */
 	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)