[PATCH 3.16 235/366] USB: serial: keyspan_pda: fix modem-status error handling

Ben Hutchings
2018-11-11T19:49:05Z

From: Johan Hovold <johan@kernel.org>

commit 01b3cdfca263a17554f7b249d20a247b2a751521 upstream.

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")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/serial/keyspan_pda.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -373,8 +373,10 @@ static int keyspan_pda_get_modem_info(st
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;