linux-kernel - [PATCH] usb: usbtmc: check size before allocating buffer and remove duplicated allocation

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-next>] [day] [month] [year] [list]

Message-Id: <20180927222332.13360-1-colin.king@canonical.com>
Date:   Thu, 27 Sep 2018 23:23:32 +0100
From:   Colin King <colin.king@...onical.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Steve Bayless <steve_bayless@...sight.com>,
        Guido Kiener <guido@...ner-muenchen.de>,
        linux-usb@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] usb: usbtmc: check size before allocating buffer and remove duplicated allocation

From: Colin Ian King <colin.king@...onical.com>

Currently the allocation of a buffer is performed before a sanity check on
the required buffer size and if the buffer size is too large the error exit
return leaks the allocated buffer.  Fix this by checking the size before
allocating.

Also, the same buffer is allocated again inside an if statement, causing
the first allocation to be leaked.  Fix this by removing this second
redundant allocation.

Detected by CoverityScan, CID#1473697 ("Resource leak")

Fixes: 658f24f4523e ("usb: usbtmc: Add ioctl for generic requests on control")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/usb/class/usbtmc.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 0fcb81a1399b..c01edff190d2 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -1895,18 +1895,14 @@ static int usbtmc_ioctl_request(struct usbtmc_device_data *data,
 	if (res)
 		return -EFAULT;
 
+	if (request.req.wLength > USBTMC_BUFSIZE)
+		return -EMSGSIZE;
+
 	buffer = kmalloc(request.req.wLength, GFP_KERNEL);
 	if (!buffer)
 		return -ENOMEM;
 
-	if (request.req.wLength > USBTMC_BUFSIZE)
-		return -EMSGSIZE;
-
 	if (request.req.wLength) {
-		buffer = kmalloc(request.req.wLength, GFP_KERNEL);
-		if (!buffer)
-			return -ENOMEM;
-
 		if ((request.req.bRequestType & USB_DIR_IN) == 0) {
 			/* Send control data to device */
 			res = copy_from_user(buffer, request.data,
-- 
2.17.1