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

PATCH New Greg Kroah-Hartman 1 participant 1 message Dec 14, 2021 USB

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Greg Kroah-Hartman

author maintainer

2021-12-14 18:46 UTC #0 lore raw

PATCH 1/1 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.

Reported-by Szymon Heidrich <[email protected]>

Fixes 153a2d7e3350 ("USB: gadget: detect too-big endpoint 0 requests")

Cc Felipe Balbi <[email protected]>

Signed-off-by Greg Kroah-Hartman <[email protected]>

---
 drivers/usb/gadget/composite.c    | 6 +++---
 drivers/usb/gadget/legacy/dbgp.c  | 6 +++---
 drivers/usb/gadget/legacy/inode.c | 6 +++---
 3 files changed, 9 insertions(+), 9 deletions(-)

drivers/usb/gadget/composite.c +3 -3

index 284eea9f6e4d..3789c329183c 100644
@@ -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

index 355bc7dab9d5..6bcbad382580 100644
@@ -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

index 63150e3889ef..3b58f4fc0a80 100644
@@ -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;
 		}
 	}

Signature · 1 line

2.34.1