kernel-6.6/usb-serial-ftdi_sio-fix-modem-status-error-handling.patch
2017-02-24 22:32:57 +03:00

40 lines
1.3 KiB
Diff

From 427c3a95e3e29e65f59d99aaf320d7506f3eed57 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 12 Jan 2017 14:56:11 +0100
Subject: USB: serial: ftdi_sio: fix modem-status error handling
From: Johan Hovold <johan@kernel.org>
commit 427c3a95e3e29e65f59d99aaf320d7506f3eed57 upstream.
Make sure to detect short responses when fetching the modem status in
order to avoid parsing uninitialised buffer data and having bits of it
leak to user space.
Note that we still allow for short 1-byte responses.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/serial/ftdi_sio.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -2433,8 +2433,12 @@ static int ftdi_get_modem_status(struct
FTDI_SIO_GET_MODEM_STATUS_REQUEST_TYPE,
0, priv->interface,
buf, len, WDR_TIMEOUT);
- if (ret < 0) {
+
+ /* NOTE: We allow short responses and handle that below. */
+ if (ret < 1) {
dev_err(&port->dev, "failed to get modem status: %d\n", ret);
+ if (ret >= 0)
+ ret = -EIO;
ret = usb_translate_errors(ret);
goto out;
}