Re: [PATCH net v3] r8152: check the informaton of the device

From: Johan Hovold
Date: Mon May 24 2021 - 04:00:46 EST


On Mon, May 24, 2021 at 02:49:42PM +0800, Hayes Wang wrote:
> Verify some fields of the USB descriptor to make sure the driver
> could be used by the device.
>
> Besides, remove the check of endpoint number in rtl8152_probe().
> usb_find_common_endpoints() includes it.
>
> BugLink: https://syzkaller.appspot.com/bug?id=912c9c373656996801b4de61f1e3cb326fe940aa
> Reported-by: syzbot+95afd23673f5dd295c57@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: c2198943e33b ("r8152: search the configuration of vendor mode")
> Signed-off-by: Hayes Wang <hayeswang@xxxxxxxxxxx>
> ---
> v3:
> Remove the check of endpoint number in rtl_check_vendor_ok().
>
> Adjust the error message and ccommit message.
>
> v2:
> Use usb_find_common_endpoints() and usb_endpoint_num() to replace original
> code.
>
> remove the check of endpoint number in rtl8152_probe(). It has been done
> in rtl_check_vendor_ok().
>
> drivers/net/usb/r8152.c | 42 ++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 37 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index 136ea06540ff..f6abb2fbf972 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -8107,6 +8107,37 @@ static void r8156b_init(struct r8152 *tp)
> tp->coalesce = 15000; /* 15 us */
> }
>
> +static bool rtl_check_vendor_ok(struct usb_interface *intf)
> +{
> + struct usb_host_interface *alt = intf->cur_altsetting;
> + struct usb_endpoint_descriptor *in, *out, *intr;
> +
> + if (usb_find_common_endpoints(alt, &in, &out, &intr, NULL) < 0) {
> + dev_err(&intf->dev, "Expected endpoints are not found\n");
> + return false;
> + }
> +
> + /* Check Rx endpoint address */
> + if (usb_endpoint_num(in) != 1) {
> + dev_err(&intf->dev, "Invalid Rx endpoint address\n");
> + return false;
> + }
> +
> + /* Check Tx endpoint address */
> + if (usb_endpoint_num(out) != 2) {
> + dev_err(&intf->dev, "Invalid Tx endpoint address\n");
> + return false;
> + }
> +
> + /* Check interrupt endpoint address */
> + if (usb_endpoint_num(intr) != 3) {
> + dev_err(&intf->dev, "Invalid interrupt endpoint address\n");
> + return false;
> + }
> +
> + return true;
> +}
> +
> static bool rtl_vendor_mode(struct usb_interface *intf)
> {
> struct usb_host_interface *alt = intf->cur_altsetting;
> @@ -8115,12 +8146,15 @@ static bool rtl_vendor_mode(struct usb_interface *intf)
> int i, num_configs;
>
> if (alt->desc.bInterfaceClass == USB_CLASS_VENDOR_SPEC)
> - return true;
> + return rtl_check_vendor_ok(intf);
>
> /* The vendor mode is not always config #1, so to find it out. */
> udev = interface_to_usbdev(intf);
> c = udev->config;
> num_configs = udev->descriptor.bNumConfigurations;
> + if (num_configs < 2)
> + return false;
> +

Nit: This check looks unnecessary also as the driver can handle a single
configuration just fine, and by removing it you'd be logging "Unexpected
Device\n" below also in the single config case.

> for (i = 0; i < num_configs; (i++, c++)) {
> struct usb_interface_descriptor *desc = NULL;
>
> @@ -8135,7 +8169,8 @@ static bool rtl_vendor_mode(struct usb_interface *intf)
> }
> }
>
> - WARN_ON_ONCE(i == num_configs);
> + if (i == num_configs)
> + dev_err(&intf->dev, "Unexpected Device\n");
>
> return false;
> }
> @@ -9381,9 +9416,6 @@ static int rtl8152_probe(struct usb_interface *intf,
> if (!rtl_vendor_mode(intf))
> return -ENODEV;
>
> - if (intf->cur_altsetting->desc.bNumEndpoints < 3)
> - return -ENODEV;
> -
> usb_reset_device(udev);
> netdev = alloc_etherdev(sizeof(struct r8152));
> if (!netdev) {

Other than that, looks good to me now.

Reviewed-by: Johan Hovold <johan@xxxxxxxxxx>

Johan