[PATCH] usb: usbtmc: Fix bug in pipe direction for control transfers

[Alan Stern <stern@rowland.harvard.edu>]

The syzbot fuzzer reported a minor bug in the usbtmc driver:

usb 5-1: BOGUS control dir, pipe 80001e80 doesn't match bRequestType 0
WARNING: CPU: 0 PID: 3813 at drivers/usb/core/urb.c:412
usb_submit_urb+0x13a5/0x1970 drivers/usb/core/urb.c:410
Modules linked in:
CPU: 0 PID: 3813 Comm: syz-executor122 Not tainted
5.17.0-rc5-syzkaller-00306-g2293be58d6a1 #0
...
Call Trace:
 <TASK>
 usb_start_wait_urb+0x113/0x530 drivers/usb/core/message.c:58
 usb_internal_control_msg drivers/usb/core/message.c:102 [inline]
 usb_control_msg+0x2a5/0x4b0 drivers/usb/core/message.c:153
 usbtmc_ioctl_request drivers/usb/class/usbtmc.c:1947 [inline]

The problem is that usbtmc_ioctl_request() uses usb_rcvctrlpipe() for
all of its transfers, whether they are in or out.  It's easy to fix.

Reported-and-tested-by: syzbot+a48e3d1a875240cab5de@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@vger.kernel.org>

---


[as1973]


 drivers/usb/class/usbtmc.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

Index: usb-devel/drivers/usb/class/usbtmc.c
===================================================================
--- usb-devel.orig/drivers/usb/class/usbtmc.c
+++ usb-devel/drivers/usb/class/usbtmc.c
@@ -1919,6 +1919,7 @@ static int usbtmc_ioctl_request(struct u
 	struct usbtmc_ctrlrequest request;
 	u8 *buffer = NULL;
 	int rv;
+	unsigned int is_in, pipe;
 	unsigned long res;
 
 	res = copy_from_user(&request, arg, sizeof(struct usbtmc_ctrlrequest));
@@ -1928,12 +1929,14 @@ static int usbtmc_ioctl_request(struct u
 	if (request.req.wLength > USBTMC_BUFSIZE)
 		return -EMSGSIZE;
 
+	is_in = request.req.bRequestType & USB_DIR_IN;
+
 	if (request.req.wLength) {
 		buffer = kmalloc(request.req.wLength, GFP_KERNEL);
 		if (!buffer)
 			return -ENOMEM;
 
-		if ((request.req.bRequestType & USB_DIR_IN) == 0) {
+		if (!is_in) {
 			/* Send control data to device */
 			res = copy_from_user(buffer, request.data,
 					     request.req.wLength);
@@ -1944,8 +1947,12 @@ static int usbtmc_ioctl_request(struct u
 		}
 	}
 
+	if (is_in)
+		pipe = usb_rcvctrlpipe(data->usb_dev, 0);
+	else
+		pipe = usb_sndctrlpipe(data->usb_dev, 0);
 	rv = usb_control_msg(data->usb_dev,
-			usb_rcvctrlpipe(data->usb_dev, 0),
+			pipe,
 			request.req.bRequest,
 			request.req.bRequestType,
 			request.req.wValue,
@@ -1957,7 +1964,7 @@ static int usbtmc_ioctl_request(struct u
 		goto exit;
 	}
 
-	if (rv && (request.req.bRequestType & USB_DIR_IN)) {
+	if (rv && is_in) {
 		/* Read control data from device */
 		res = copy_to_user(request.data, buffer, rv);
 		if (res)