Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753425AbdFGXb5 (ORCPT ); Wed, 7 Jun 2017 19:31:57 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:50746 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753334AbdFGXFZ (ORCPT ); Wed, 7 Jun 2017 19:05:25 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Johan Hovold , Willy Tarreau Subject: [PATCH 3.10 130/250] USB: serial: spcp8x5: fix modem-status handling Date: Thu, 8 Jun 2017 00:58:36 +0200 Message-Id: <1496876436-32402-131-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1496876436-32402-1-git-send-email-w@1wt.eu> References: <1496876436-32402-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1580 Lines: 48 From: Johan Hovold commit 5ed8d41023751bdd3546f2fe4118304357efe8d2 upstream. Make sure to detect short control transfers and return zero on success when retrieving the modem status. This fixes the TIOCMGET implementation which since e1ed212d8593 ("USB: spcp8x5: add proper modem-status support") has returned TIOCM_LE on successful retrieval, and avoids leaking bits from the stack on short transfers. This also fixes the carrier-detect implementation which since the above mentioned commit unconditionally has returned true. Fixes: e1ed212d8593 ("USB: spcp8x5: add proper modem-status support") Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold Signed-off-by: Willy Tarreau --- drivers/usb/serial/spcp8x5.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/spcp8x5.c b/drivers/usb/serial/spcp8x5.c index 20f00bc..595a3f0 100644 --- a/drivers/usb/serial/spcp8x5.c +++ b/drivers/usb/serial/spcp8x5.c @@ -231,11 +231,17 @@ static int spcp8x5_get_msr(struct usb_serial_port *port, u8 *status) ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), GET_UART_STATUS, GET_UART_STATUS_TYPE, 0, GET_UART_STATUS_MSR, buf, 1, 100); - if (ret < 0) + if (ret < 1) { dev_err(&port->dev, "failed to get modem status: %d", ret); + if (ret >= 0) + ret = -EIO; + goto out; + } dev_dbg(&port->dev, "0xc0:0x22:0:6 %d - 0x02%x", ret, *buf); *status = *buf; + ret = 0; +out: kfree(buf); return ret; -- 2.8.0.rc2.1.gbe9624a