From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751935AbdCRSxH (ORCPT ); Sat, 18 Mar 2017 14:53:07 -0400 Received: from mout.gmx.net ([212.227.17.21]:65067 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751699AbdCRSxC (ORCPT ); Sat, 18 Mar 2017 14:53:02 -0400 From: Tobias Herzog To: oneukum@suse.com Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/4] cdc-acm: fix possible invalid access when processing notification Date: Sat, 18 Mar 2017 19:52:37 +0100 Message-Id: <1489863159-10972-3-git-send-email-t-herzog@gmx.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1489863159-10972-1-git-send-email-t-herzog@gmx.de> References: <1479118868.21146.4.camel@suse.com> <1489863159-10972-1-git-send-email-t-herzog@gmx.de> X-Provags-ID: V03:K0:GTSJ64jkc7YbuRNSOydnf6+/PMJ3UteKIX+9FfJ38l//eWAQwyY mQoRCCjO4438gHwVU+wofvhN07xjzDjccnliQJ9zzrifZC569nlzV5gQtH+0eF10cOrmJBZ 863mZSHowtBcMHlSok/nT4/BnEmd4lNBGmV3Cz1SCZiFYp7Jj/IeYRSnz8weEtLFc2pT37b BKGw0jntgcs7rxuOuTUaw== X-UI-Out-Filterresults: notjunk:1;V01:K0:zwopMtpqNqk=:YtDhBWQnuxqoQ3ShpQK9Dl yvB6pWFMPTb9HAIyMJb24gq5NooGa5nmuGMhKNAlm/qTGuCuMUkIxZRIYeAbfVPIz/5VFZ9wa 2bVvsFjSLvUV/Tzmy+5HkpoPl4Vw3/6q8y/ZtBzMCQlFOoGH9hxnifgVYAU6rXMDiT7iMUjei uGoIgV03RmC15W+RfJbo+XOik0PLD/RElOUaBhDZfw+LyixaWSbCl9XB7yJjMKAvDYKSOrS/Q cz8BAS+HQSNa2OcgIXxbY3mC8N87I55nNv9I0tyLjqVVkqN0kBryHzwMNKdnJic4l/aGspPDp OIsh0AHzJWGMpHoFtAwn6TzS6b83YTxu4EBCxhrQ7DA3qLqRz6mRNv+xqA7RE0X/C5AWyEQ+l uupkSOlWHL2I8kqX0ei5xjlKk3SYxqiSXakfe4dfBAr8sQzkr/1i9G+h7oKHCGj6Tjg9ZBGNf JoZLKKlxH3KGoL7fy4Hm1tI1kx/E1a2OLtONK3w52hDBCPM+96gcXhbU7nm3jNqLKaPcKLO4g BDiHZaw1jSApXOCFWzO/LyCybfUvROcGOmmowFLoohqQeoCdL96up+wkS69qwR4B4Bs4bPnN4 pAdcXmtibb5t//gOhX5+HLRPu4iJjfdwT6oA2KMAhFY2qvvn+xJ0EwZ88Y2IO1zy2s9aZbp0I 3qAppRE+vzPXS+wY74f+5ibiOKUlHDaXXlDPocSnV3Kwk2twVNHGdugetpn4RcLsf6cDGQF1Y rRUT67rKdTrhgoh+rdcNHoqwaNe8c1TmWvaGpPOdIyP0EIW/1DiXbhKk95Q= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Notifications may only be 8 bytes so long. Accessing the 9th and 10th byte of unimplemented/unknown notifications may be insecure. Also check the length of known notifications before accessing anything behind the 8th byte. Signed-off-by: Tobias Herzog --- drivers/usb/class/cdc-acm.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 74acca1..a7c8878 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -296,6 +296,12 @@ static void acm_process_notification(struct acm *acm, unsigned char *buf) break; case USB_CDC_NOTIFY_SERIAL_STATE: + if (le16_to_cpu(dr->wLength) != 2) { + dev_dbg(&acm->control->dev, + "%s - malformed serial state\n", __func__); + break; + } + newctrl = get_unaligned_le16(data); if (!acm->clocal && (acm->ctrlin & ~newctrl & ACM_CTRL_DCD)) { @@ -332,11 +338,10 @@ static void acm_process_notification(struct acm *acm, unsigned char *buf) default: dev_dbg(&acm->control->dev, - "%s - unknown notification %d received: index %d " - "len %d data0 %d data1 %d\n", + "%s - unknown notification %d received: index %d len %d\n", __func__, dr->bNotificationType, dr->wIndex, - dr->wLength, data[0], data[1]); + dr->wLength); } } -- 2.1.4