Commit f08adf5a authored Dec 14, 2021 by Greg Kroah-Hartman

USB: gadget: bRequestType is a bitfield, not a enum



Szymon rightly pointed out that the previous check for the endpoint
direction in bRequestType was not looking at only the bit involved, but
rather the whole value.  Normally this is ok, but for some request
types, bits other than bit 8 could be set and the check for the endpoint
length could not stall correctly.

Fix that up by only checking the single bit.

Fixes: 153a2d7e ("USB: gadget: detect too-big endpoint 0 requests")
Cc: Felipe Balbi <balbi@kernel.org>
Reported-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Link: https://lore.kernel.org/r/20211214184621.385828-1-gregkh@linuxfoundation.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 99ea221f

drivers/usb/gadget/composite.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1680,14 +1680,14 @@ composite_setup(struct usb_gadget gadget, const struct usb_ctrlrequest ctrl)
		u8 endp;

		if (w_length > USB_COMP_EP0_BUFSIZ) {
		if (ctrl->bRequestType == USB_DIR_OUT) {
		goto done;
		} else {
		if (ctrl->bRequestType & USB_DIR_IN) {
		/* Cast away the const, we are going to overwrite on purpose. */
		__le16 temp = (__le16 )&ctrl->wLength;

		*temp = cpu_to_le16(USB_COMP_EP0_BUFSIZ);
		w_length = USB_COMP_EP0_BUFSIZ;
		} else {
		goto done;
		}
		}

drivers/usb/gadget/legacy/dbgp.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -346,14 +346,14 @@ static int dbgp_setup(struct usb_gadget *gadget,
		u16 len = 0;

		if (length > DBGP_REQ_LEN) {
		if (ctrl->bRequestType == USB_DIR_OUT) {
		return err;
		} else {
		if (ctrl->bRequestType & USB_DIR_IN) {
		/* Cast away the const, we are going to overwrite on purpose. */
		__le16 temp = (__le16 )&ctrl->wLength;

		*temp = cpu_to_le16(DBGP_REQ_LEN);
		length = DBGP_REQ_LEN;
		} else {
		return err;
		}
		}

drivers/usb/gadget/legacy/inode.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1334,14 +1334,14 @@ gadgetfs_setup (struct usb_gadget gadget, const struct usb_ctrlrequest ctrl)
		u16 w_length = le16_to_cpu(ctrl->wLength);

		if (w_length > RBUF_SIZE) {
		if (ctrl->bRequestType == USB_DIR_OUT) {
		return value;
		} else {
		if (ctrl->bRequestType & USB_DIR_IN) {
		/* Cast away the const, we are going to overwrite on purpose. */
		__le16 temp = (__le16 )&ctrl->wLength;

		*temp = cpu_to_le16(RBUF_SIZE);
		w_length = RBUF_SIZE;
		} else {
		return value;
		}
		}