From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59096 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733116AbeIXSnJ (ORCPT ); Mon, 24 Sep 2018 14:43:09 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Hutchings Subject: [PATCH 4.18 131/235] USB: yurex: Fix buffer over-read in yurex_write() Date: Mon, 24 Sep 2018 13:51:57 +0200 Message-Id: <20180924113118.976640186@linuxfoundation.org> In-Reply-To: <20180924113103.999624566@linuxfoundation.org> References: <20180924113103.999624566@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings commit 7e10f14ebface44a48275c8d6dc1caae3668d5a9 upstream. If the written data starts with a digit, yurex_write() tries to parse it as an integer using simple_strtoull(). This requires a null- terminator, and currently there's no guarantee that there is one. (The sample program at https://github.com/NeoCat/YUREX-driver-for-Linux/blob/master/sample/yurex_clock.pl writes an integer without a null terminator. It seems like it must have worked by chance!) Always add a null byte after the written data. Enlarge the buffer to allow for this. Cc: stable@vger.kernel.org Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- drivers/usb/misc/yurex.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/usb/misc/yurex.c +++ b/drivers/usb/misc/yurex.c @@ -421,13 +421,13 @@ static ssize_t yurex_write(struct file * { struct usb_yurex *dev; int i, set = 0, retval = 0; - char buffer[16]; + char buffer[16 + 1]; char *data = buffer; unsigned long long c, c2 = 0; signed long timeout = 0; DEFINE_WAIT(wait); - count = min(sizeof(buffer), count); + count = min(sizeof(buffer) - 1, count); dev = file->private_data; /* verify that we actually have some data to write */ @@ -446,6 +446,7 @@ static ssize_t yurex_write(struct file * retval = -EFAULT; goto error; } + buffer[count] = 0; memset(dev->cntl_buffer, CMD_PADDING, YUREX_BUF_SIZE); switch (buffer[0]) {