[PATCH] USB: gadget: bRequestType is a bitfield, not a enum

Greg Kroah-Hartman
2021-12-14T18:46:33Z

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 <szymon.heidrich@gmail.com>
Fixes: 153a2d7e3350 ("USB: gadget: detect too-big endpoint 0 requests")
Cc: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 284eea9f6e4d..3789c329183c 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -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;
}
}

diff --git a/drivers/usb/gadget/legacy/dbgp.c b/drivers/usb/gadget/legacy/dbgp.c
index 355bc7dab9d5..6bcbad382580 100644
--- a/drivers/usb/gadget/legacy/dbgp.c
+++ b/drivers/usb/gadget/legacy/dbgp.c
@@ -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;
}
}

diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index 63150e3889ef..3b58f4fc0a80 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -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;
}
}

--
2.34.1