2022-05-29 07:34:02

by Zheyu Ma

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Subject: [PATCH v3] char: xillybus: Check endpoint type at probe time

The driver submits bulk urb without checking the endpoint type is
actually bulk.

[ 3.108690] usb 1-1: BOGUS urb xfer, pipe 3 != type 1
[ 3.108983] WARNING: CPU: 0 PID: 211 at drivers/usb/core/urb.c:503 usb_submit_urb+0xcd9/0x18b0
[ 3.110976] RIP: 0010:usb_submit_urb+0xcd9/0x18b0
[ 3.115318] Call Trace:
[ 3.115452] <TASK>
[ 3.115570] try_queue_bulk_in+0x43c/0x6e0 [xillyusb]
[ 3.115838] xillyusb_probe+0x488/0x1230 [xillyusb]

Add a check at probe time to fix the bug.

Signed-off-by: Zheyu Ma <[email protected]>
---
Changes in v3:
- Check the endpoint type more earlier
Changes in v2:
- Check the endpoint type at probe time
---
drivers/char/xillybus/xillyusb.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)

diff --git a/drivers/char/xillybus/xillyusb.c b/drivers/char/xillybus/xillyusb.c
index dc3551796e5e..4ed19a2a04e3 100644
--- a/drivers/char/xillybus/xillyusb.c
+++ b/drivers/char/xillybus/xillyusb.c
@@ -167,6 +167,7 @@ struct xillyusb_dev {
struct device *dev; /* For dev_err() and such */
struct kref kref;
struct workqueue_struct *workq;
+ struct usb_interface *intf;

int error;
spinlock_t error_lock; /* protect @error */
@@ -1891,6 +1892,17 @@ static const struct file_operations xillyusb_fops = {

static int xillyusb_setup_base_eps(struct xillyusb_dev *xdev)
{
+ int ret;
+ struct usb_endpoint_descriptor *in, *out;
+
+ ret = usb_find_common_endpoints(xdev->intf->cur_altsetting, &in, &out, NULL, NULL);
+ if (ret)
+ return ret;
+
+ if (in->bEndpointAddress != (IN_EP_NUM | USB_DIR_IN) ||
+ out->bEndpointAddress != (MSG_EP_NUM | USB_DIR_OUT))
+ return -EINVAL;
+
xdev->msg_ep = endpoint_alloc(xdev, MSG_EP_NUM | USB_DIR_OUT,
bulk_out_work, 1, 2);
if (!xdev->msg_ep)
@@ -1916,6 +1928,21 @@ static int xillyusb_setup_base_eps(struct xillyusb_dev *xdev)
return -ENOMEM;
}

+static int xillyusb_check_endpoint(struct xillyusb_dev *xdev, u8 addr)
+{
+ int i;
+ struct usb_host_interface *if_desc = xdev->intf->altsetting;
+
+ for (i = 0; i < if_desc->desc.bNumEndpoints; i++) {
+ struct usb_endpoint_descriptor *ep = &if_desc->endpoint[i].desc;
+
+ if (ep->bEndpointAddress == addr && usb_endpoint_is_bulk_out(ep))
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
static int setup_channels(struct xillyusb_dev *xdev,
__le16 *chandesc,
int num_channels)
@@ -1962,6 +1989,10 @@ static int setup_channels(struct xillyusb_dev *xdev,
chan->out_log2_element_size = out_desc & 0x0f;
chan->out_log2_fifo_size =
((out_desc >> 8) & 0x1f) + 16;
+ if (xillyusb_check_endpoint(xdev, (i+2) | USB_DIR_OUT)) {
+ kfree(xdev->channels);
+ return -EINVAL;
+ }
}
}

@@ -2125,6 +2156,7 @@ static int xillyusb_probe(struct usb_interface *interface,
mutex_init(&xdev->process_in_mutex);
mutex_init(&xdev->msg_mutex);

+ xdev->intf = interface;
xdev->udev = usb_get_dev(interface_to_usbdev(interface));
xdev->dev = &interface->dev;
xdev->error = 0;
--
2.25.1



2022-05-31 13:52:58

by Eli Billauer

[permalink] [raw]
Subject: Re: [PATCH v3] char: xillybus: Check endpoint type at probe time

On 29/05/22 09:58, Zheyu Ma wrote:
> static int xillyusb_setup_base_eps(struct xillyusb_dev *xdev)
> {
> + int ret;
> + struct usb_endpoint_descriptor *in, *out;
> +
> + ret = usb_find_common_endpoints(xdev->intf->cur_altsetting,&in,&out, NULL, NULL);
> + if (ret)
> + return ret;
> +
> + if (in->bEndpointAddress != (IN_EP_NUM | USB_DIR_IN) ||
> + out->bEndpointAddress != (MSG_EP_NUM | USB_DIR_OUT))
> + return -EINVAL;
> +
>
As far as I understand, this finds the first BULK endpoints in both
directions, and verifies that their addresses are MSG_EP_NUM and
IN_EP_NUM. Because both of these happen to equal 1, I suppose this
indeed checks the right thing. But am I right that this won't work if
either MSG_EP_NUM or IN_EP_NUM have a value that isn't 1? Not that I
think that will ever happen, but still.

> +static int xillyusb_check_endpoint(struct xillyusb_dev *xdev, u8 addr)
> +{
> + int i;
> + struct usb_host_interface *if_desc = xdev->intf->altsetting;
> +
> + for (i = 0; i< if_desc->desc.bNumEndpoints; i++) {
> + struct usb_endpoint_descriptor *ep =&if_desc->endpoint[i].desc;
> +
> + if (ep->bEndpointAddress == addr&& usb_endpoint_is_bulk_out(ep))
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
>
>
Given that you've added this function, why isn't it used in
xillyusb_setup_base_eps()?

Thanks,
Eli




2022-06-01 19:36:40

by Zheyu Ma

[permalink] [raw]
Subject: Re: [PATCH v3] char: xillybus: Check endpoint type at probe time

On Mon, May 30, 2022 at 11:13 PM Eli Billauer <[email protected]> wrote:
>
> On 29/05/22 09:58, Zheyu Ma wrote:
> > static int xillyusb_setup_base_eps(struct xillyusb_dev *xdev)
> > {
> > + int ret;
> > + struct usb_endpoint_descriptor *in, *out;
> > +
> > + ret = usb_find_common_endpoints(xdev->intf->cur_altsetting,&in,&out, NULL, NULL);
> > + if (ret)
> > + return ret;
> > +
> > + if (in->bEndpointAddress != (IN_EP_NUM | USB_DIR_IN) ||
> > + out->bEndpointAddress != (MSG_EP_NUM | USB_DIR_OUT))
> > + return -EINVAL;
> > +
> >
> As far as I understand, this finds the first BULK endpoints in both
> directions, and verifies that their addresses are MSG_EP_NUM and
> IN_EP_NUM. Because both of these happen to equal 1, I suppose this
> indeed checks the right thing. But am I right that this won't work if
> either MSG_EP_NUM or IN_EP_NUM have a value that isn't 1? Not that I
> think that will ever happen, but still.

Indeed, the correctness of this code comes from the fact that both
MSG_EP_NUM and IN_EP_NUM are the first bulk endpoint, without such an
assumption this check does not hold.
I did this just for convenience, we can also use
xillyusb_check_endpoint() to check them.

> > +static int xillyusb_check_endpoint(struct xillyusb_dev *xdev, u8 addr)
> > +{
> > + int i;
> > + struct usb_host_interface *if_desc = xdev->intf->altsetting;
> > +
> > + for (i = 0; i< if_desc->desc.bNumEndpoints; i++) {
> > + struct usb_endpoint_descriptor *ep =&if_desc->endpoint[i].desc;
> > +
> > + if (ep->bEndpointAddress == addr&& usb_endpoint_is_bulk_out(ep))
> > + return 0;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> >
> >
> Given that you've added this function, why isn't it used in
> xillyusb_setup_base_eps()?

It is feasible to use this function for checking in
xillyusb_setup_base_eps(), perhaps with some modifications. Anyway, I
will do so in the next version of the patch.

Thanks,
Zheyu Ma