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From 01b3cdfca263a17554f7b249d20a247b2a751521 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Wed, 4 Jul 2018 17:02:16 +0200
Subject: [PATCH] USB: serial: keyspan_pda: fix modem-status error handling
Git-commit: 01b3cdfca263a17554f7b249d20a247b2a751521
Patch-mainline: v4.18-rc5
References: bsc#1100132

Fix broken modem-status error handling which could lead to bits of slab
data leaking to user space.

Fixes: 3b36a8fd6777 ("usb: fix uninitialized variable warning in keyspan_pda")
Cc: stable <stable@vger.kernel.org>     # 2.6.27
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/serial/keyspan_pda.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index 5169624d8b11..38d43c4b7ce5 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -369,8 +369,10 @@ static int keyspan_pda_get_modem_info(struct usb_serial *serial,
 			     3, /* get pins */
 			     USB_TYPE_VENDOR|USB_RECIP_INTERFACE|USB_DIR_IN,
 			     0, 0, data, 1, 2000);
-	if (rc >= 0)
+	if (rc == 1)
 		*value = *data;
+	else if (rc >= 0)
+		rc = -EIO;
 
 	kfree(data);
 	return rc;
-- 
2.16.4