usb: gadget: dfu: Fix the unchecked length field

DFU implementation does not bound the length field in USB
DFU download setup packets, and it does not verify that
the transfer direction. Fixing the length and transfer
direction.

CVE-2022-2347

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Reviewed-by: Marek Vasut <marex@denx.de>

diff --git a/drivers/usb/gadget/f_dfu.c b/drivers/usb/gadget/f_dfu.c
index e9340ff..33ef62f 100644 (file)
--- a/drivers/usb/gadget/f_dfu.c
+++ b/drivers/usb/gadget/f_dfu.c
@@ -321,23 +321,29 @@ static int state_dfu_idle(struct f_dfu *f_dfu,
        u16 len = le16_to_cpu(ctrl->wLength);
        int value = 0;
 
+       len = len > DFU_USB_BUFSIZ ? DFU_USB_BUFSIZ : len;
+
        switch (ctrl->bRequest) {
        case USB_REQ_DFU_DNLOAD:
-               if (len == 0) {
-                       f_dfu->dfu_state = DFU_STATE_dfuERROR;
-                       value = RET_STALL;
-                       break;
+               if (ctrl->bRequestType == USB_DIR_OUT) {
+                       if (len == 0) {
+                               f_dfu->dfu_state = DFU_STATE_dfuERROR;
+                               value = RET_STALL;
+                               break;
+                       }
+                       f_dfu->dfu_state = DFU_STATE_dfuDNLOAD_SYNC;
+                       f_dfu->blk_seq_num = w_value;
+                       value = handle_dnload(gadget, len);
                }
-               f_dfu->dfu_state = DFU_STATE_dfuDNLOAD_SYNC;
-               f_dfu->blk_seq_num = w_value;
-               value = handle_dnload(gadget, len);
                break;
        case USB_REQ_DFU_UPLOAD:
-               f_dfu->dfu_state = DFU_STATE_dfuUPLOAD_IDLE;
-               f_dfu->blk_seq_num = 0;
-               value = handle_upload(req, len);
-               if (value >= 0 && value < len)
-                       f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+               if (ctrl->bRequestType == USB_DIR_IN) {
+                       f_dfu->dfu_state = DFU_STATE_dfuUPLOAD_IDLE;
+                       f_dfu->blk_seq_num = 0;
+                       value = handle_upload(req, len);
+                       if (value >= 0 && value < len)
+                               f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+               }
                break;
        case USB_REQ_DFU_ABORT:
                /* no zlp? */
@@ -426,11 +432,15 @@ static int state_dfu_dnload_idle(struct f_dfu *f_dfu,
        u16 len = le16_to_cpu(ctrl->wLength);
        int value = 0;
 
+       len = len > DFU_USB_BUFSIZ ? DFU_USB_BUFSIZ : len;
+
        switch (ctrl->bRequest) {
        case USB_REQ_DFU_DNLOAD:
-               f_dfu->dfu_state = DFU_STATE_dfuDNLOAD_SYNC;
-               f_dfu->blk_seq_num = w_value;
-               value = handle_dnload(gadget, len);
+               if (ctrl->bRequestType == USB_DIR_OUT) {
+                       f_dfu->dfu_state = DFU_STATE_dfuDNLOAD_SYNC;
+                       f_dfu->blk_seq_num = w_value;
+                       value = handle_dnload(gadget, len);
+               }
                break;
        case USB_REQ_DFU_ABORT:
                f_dfu->dfu_state = DFU_STATE_dfuIDLE;
@@ -513,13 +523,17 @@ static int state_dfu_upload_idle(struct f_dfu *f_dfu,
        u16 len = le16_to_cpu(ctrl->wLength);
        int value = 0;
 
+       len = len > DFU_USB_BUFSIZ ? DFU_USB_BUFSIZ : len;
+
        switch (ctrl->bRequest) {
        case USB_REQ_DFU_UPLOAD:
-               /* state transition if less data then requested */
-               f_dfu->blk_seq_num = w_value;
-               value = handle_upload(req, len);
-               if (value >= 0 && value < len)
-                       f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+               if (ctrl->bRequestType == USB_DIR_IN) {
+                       /* state transition if less data then requested */
+                       f_dfu->blk_seq_num = w_value;
+                       value = handle_upload(req, len);
+                       if (value >= 0 && value < len)
+                               f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+               }
                break;
        case USB_REQ_DFU_ABORT:
                f_dfu->dfu_state = DFU_STATE_dfuIDLE;
@@ -595,6 +609,8 @@ dfu_handle(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
        int value = 0;
        u8 req_type = ctrl->bRequestType & USB_TYPE_MASK;
 
+       len = len > DFU_USB_BUFSIZ ? DFU_USB_BUFSIZ : len;
+
        debug("w_value: 0x%x len: 0x%x\n", w_value, len);
        debug("req_type: 0x%x ctrl->bRequest: 0x%x f_dfu->dfu_state: 0x%x\n",
               req_type, ctrl->bRequest, f_dfu->dfu_state);
@@ -614,7 +630,7 @@ dfu_handle(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
                value = dfu_state[f_dfu->dfu_state] (f_dfu, ctrl, gadget, req);
 
        if (value >= 0) {
-               req->length = value;
+               req->length = value > DFU_USB_BUFSIZ ? DFU_USB_BUFSIZ : value;
                req->zero = value < len;
                value = usb_ep_queue(gadget->ep0, req, 0);
                if (value < 0) {