linux-kernel - [PATCH 4.9 15/31] USB: gadget: bRequestType is a bitfield, not a enum

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Date:   Mon, 20 Dec 2021 15:34:15 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Felipe Balbi <balbi@...nel.org>,
        Szymon Heidrich <szymon.heidrich@...il.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 15/31] USB: gadget: bRequestType is a bitfield, not a enum

From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

[ Upstream commit f08adf5add9a071160c68bb2a61d697f39ab0758 ]

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: 153a2d7e3350 ("USB: gadget: detect too-big endpoint 0 requests")
Cc: Felipe Balbi <balbi@...nel.org>
Reported-by: Szymon Heidrich <szymon.heidrich@...il.com>
Link: https://lore.kernel.org/r/20211214184621.385828-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 3d14a316830a6..a7c44a3cb2d25 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1632,14 +1632,14 @@ 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;
 		}
 	}
 
diff --git a/drivers/usb/gadget/legacy/dbgp.c b/drivers/usb/gadget/legacy/dbgp.c
index f1c5a22704b28..e8818ad973e4b 100644
--- a/drivers/usb/gadget/legacy/dbgp.c
+++ b/drivers/usb/gadget/legacy/dbgp.c
@@ -345,14 +345,14 @@ 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;
 		}
 	}
 
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index d39bd1a1ab8fc..19eb954a7afa3 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -1339,14 +1339,14 @@ 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;
 		}
 	}
 
-- 
2.34.1