[PATCH] serial167: Read buffer overflow

[Roel Kluin <roel.kluin@gmail.com>]

Check whether index is within bounds before grabbing the element.
Also, since NR_PORTS is defined ARRAY_SIZE(cy_port),
cy_port[NR_PORTS] is out of bounds as well. 

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/drivers/char/serial167.c b/drivers/char/serial167.c
index 51e7a46..affa5e2 100644
--- a/drivers/char/serial167.c
+++ b/drivers/char/serial167.c
@@ -222,7 +222,7 @@ static inline int serial_paranoia_check(struct cyclades_port *info, char *name,
 	}
 
 	if ((long)info < (long)(&cy_port[0])
-	    || (long)(&cy_port[NR_PORTS]) < (long)info) {
+	    || (long)(&cy_port[NR_PORTS-1]) < (long)info) {
 		printk("Warning: cyclades_port out of range for (%s) in %s\n",
 				name, routine);
 		return 1;
@@ -521,15 +521,13 @@ static irqreturn_t cd2401_tx_interrupt(int irq, void *dev_id)
 		panic("TxInt on debug port!!!");
 	}
 #endif
-
-	info = &cy_port[channel];
-
 	/* validate the port number (as configured and open) */
 	if ((channel < 0) || (NR_PORTS <= channel)) {
 		base_addr[CyIER] &= ~(CyTxMpty | CyTxRdy);
 		base_addr[CyTEOIR] = CyNOTRANS;
 		return IRQ_HANDLED;
 	}
+	info = &cy_port[channel];
 	info->last_active = jiffies;
 	if (info->tty == 0) {
 		base_addr[CyIER] &= ~(CyTxMpty | CyTxRdy);