linux-kernel - [PATCH 4.10 07/21] USB: serial: ftdi_sio: fix modem-status error handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20170224083851.655710736@linuxfoundation.org>
Date:   Fri, 24 Feb 2017 09:40:06 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Johan Hovold <johan@...nel.org>
Subject: [PATCH 4.10 07/21] USB: serial: ftdi_sio: fix modem-status error handling

4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@...nel.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@...uxfoundation.org>
Signed-off-by: Johan Hovold <johan@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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
@@ -2428,8 +2428,12 @@ 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;
 	}