From: Shuah Khan <shuahkh@osg.samsung.com>
To: shuah@kernel.org, valentina.manea.m@gmail.com,
gregkh@linuxfoundation.org
Cc: Shuah Khan <shuahkh@osg.samsung.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input
Date: Thu, 7 Dec 2017 14:16:48 -0700 [thread overview]
Message-ID: <db402ad4a294b04037aac876e52c24a9f82f5730.1512672005.git.shuahkh@osg.samsung.com> (raw)
In-Reply-To: <cover.1512672005.git.shuahkh@osg.samsung.com>
In-Reply-To: <cover.1512672005.git.shuahkh@osg.samsung.com>
Harden CMD_SUBMIT path to handle malicious input that could trigger
large memory allocations. Add checks to validate transfer_buffer_length
and number_of_packets to protect against bad input requesting for
unbounded memory allocations. Validate early in get_pipe() and return
failure.
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
drivers/usb/usbip/stub_rx.c | 35 +++++++++++++++++++++++++++++++----
1 file changed, 31 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
index 4d61063c259d..493ac2928391 100644
--- a/drivers/usb/usbip/stub_rx.c
+++ b/drivers/usb/usbip/stub_rx.c
@@ -322,11 +322,13 @@ static struct stub_priv *stub_priv_alloc(struct stub_device *sdev,
return priv;
}
-static int get_pipe(struct stub_device *sdev, int epnum, int dir)
+static int get_pipe(struct stub_device *sdev, struct usbip_header *pdu)
{
struct usb_device *udev = sdev->udev;
struct usb_host_endpoint *ep;
struct usb_endpoint_descriptor *epd = NULL;
+ int epnum = pdu->base.ep;
+ int dir = pdu->base.direction;
if (epnum < 0 || epnum > 15)
goto err_ret;
@@ -339,6 +341,15 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
goto err_ret;
epd = &ep->desc;
+
+ /* validate transfer_buffer_length */
+ if (pdu->u.cmd_submit.transfer_buffer_length > INT_MAX) {
+ dev_err(&sdev->udev->dev,
+ "CMD_SUBMIT: -EMSGSIZE transfer_buffer_length %d\n",
+ pdu->u.cmd_submit.transfer_buffer_length);
+ return -1;
+ }
+
if (usb_endpoint_xfer_control(epd)) {
if (dir == USBIP_DIR_OUT)
return usb_sndctrlpipe(udev, epnum);
@@ -361,6 +372,21 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
}
if (usb_endpoint_xfer_isoc(epd)) {
+ /* validate packet size and number of packets */
+ unsigned int maxp, packets, bytes;
+
+ maxp = usb_endpoint_maxp(epd);
+ maxp *= usb_endpoint_maxp_mult(epd);
+ bytes = pdu->u.cmd_submit.transfer_buffer_length;
+ packets = DIV_ROUND_UP(bytes, maxp);
+
+ if (pdu->u.cmd_submit.number_of_packets < 0 ||
+ pdu->u.cmd_submit.number_of_packets > packets) {
+ dev_err(&sdev->udev->dev,
+ "CMD_SUBMIT: isoc invalid num packets %d\n",
+ pdu->u.cmd_submit.number_of_packets);
+ return -1;
+ }
if (dir == USBIP_DIR_OUT)
return usb_sndisocpipe(udev, epnum);
else
@@ -369,7 +395,7 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
err_ret:
/* NOT REACHED */
- dev_err(&sdev->udev->dev, "get pipe() invalid epnum %d\n", epnum);
+ dev_err(&sdev->udev->dev, "CMD_SUBMIT: invalid epnum %d\n", epnum);
return -1;
}
@@ -434,7 +460,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
struct stub_priv *priv;
struct usbip_device *ud = &sdev->ud;
struct usb_device *udev = sdev->udev;
- int pipe = get_pipe(sdev, pdu->base.ep, pdu->base.direction);
+ int pipe = get_pipe(sdev, pdu);
if (pipe == -1)
return;
@@ -456,7 +482,8 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
}
/* allocate urb transfer buffer, if needed */
- if (pdu->u.cmd_submit.transfer_buffer_length > 0) {
+ if (pdu->u.cmd_submit.transfer_buffer_length > 0 &&
+ pdu->u.cmd_submit.transfer_buffer_length <= INT_MAX) {
priv->urb->transfer_buffer =
kzalloc(pdu->u.cmd_submit.transfer_buffer_length,
GFP_KERNEL);
--
2.14.1
next prev parent reply other threads:[~2017-12-07 21:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-07 21:16 [PATCH 0/4] USB over IP Secuurity fixes Shuah Khan
2017-12-07 21:16 ` [PATCH 1/4] usbip: fix stub_rx: get_pipe() to validate endpoint number Shuah Khan
2017-12-07 21:16 ` Shuah Khan [this message]
2017-12-07 21:16 ` [PATCH 3/4] usbip: prevent vhci_hcd driver from leaking a socket pointer address Shuah Khan
2017-12-07 21:16 ` [PATCH 4/4] usbip: fix stub_send_ret_submit() vulnerability to null transfer_buffer Shuah Khan
2017-12-08 6:25 ` [PATCH 0/4] USB over IP Secuurity fixes Greg KH
2017-12-08 15:41 ` Shuah Khan
2017-12-08 15:14 ` Secunia Research
2017-12-08 15:44 ` Shuah Khan
2017-12-08 16:33 ` Greg KH
2017-12-08 16:41 ` Shuah Khan
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