From e0783ed3660aecb83af580cdace583980b22809b Mon Sep 17 00:00:00 2001
From: Finn Thain <fthain@telegraphics.com.au>
Date: Sun, 3 Jan 2016 16:05:45 +1100
Subject: ncr5380: Fix off-by-one bug in extended_msg[] bounds check

Fix the array bounds check when transferring an extended message from the
target.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index 78cf970..c6b69ee 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -2039,7 +2039,8 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance) {
 
 					dprintk(NDEBUG_EXTENDED, "scsi%d : length=%d, code=0x%02x\n", instance->host_no, (int) extended_msg[1], (int) extended_msg[2]);
 
-					if (!len && extended_msg[1] <= (sizeof(extended_msg) - 1)) {
+					if (!len && extended_msg[1] > 0 &&
+					    extended_msg[1] <= sizeof(extended_msg) - 2) {
 						/* Accept third byte by clearing ACK */
 						NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 						len = extended_msg[1] - 1;
diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c
index 214f43b..c14cfb1 100644
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -2330,8 +2330,8 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
 					dprintk(NDEBUG_EXTENDED, "scsi%d: length=%d, code=0x%02x\n", HOSTNO,
 						   (int)extended_msg[1], (int)extended_msg[2]);
 
-					if (!len && extended_msg[1] <=
-					    (sizeof(extended_msg) - 1)) {
+					if (!len && extended_msg[1] > 0 &&
+					    extended_msg[1] <= sizeof(extended_msg) - 2) {
 						/* Accept third byte by clearing ACK */
 						NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 						len = extended_msg[1] - 1;
-- 
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