USB: gadget: detect too-big endpoint 0 requests

commit 153a2d7e3350cc89d406ba2d35be8793a64c2038 upstream.

Sometimes USB hosts can ask for buffers that are too large from endpoint
0, which should not be allowed.  If this happens for OUT requests, stall
the endpoint, but for IN requests, trim the request size to the endpoint
buffer size.

Co-developed-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index bb72d55a58b5a6c3dd87382c2a66ffd9f39f58e8..3a49941c664f162a4efe19a2d8d614cedb34d5bb 100644 (file)
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1484,6 +1484,18 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
        struct usb_function             *f = NULL;
        u8                              endp;
 
+       if (w_length > USB_COMP_EP0_BUFSIZ) {
+               if (ctrl->bRequestType == USB_DIR_OUT) {
+                       goto done;
+               } else {
+                       /* 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;
+               }
+       }
+
        /* partial re-init of the response message; the function or the
         * gadget might need to intercept e.g. a control-OUT completion
         * when we delegate to it.

diff --git a/drivers/usb/gadget/legacy/dbgp.c b/drivers/usb/gadget/legacy/dbgp.c
index 99ca3dabc4f34c6c2cacc7957323128b2b10f544..ed19c12bea250e4ec611223d76a0ab3b8235b2df 100644 (file)
--- a/drivers/usb/gadget/legacy/dbgp.c
+++ b/drivers/usb/gadget/legacy/dbgp.c
@@ -344,6 +344,19 @@ static int dbgp_setup(struct usb_gadget *gadget,
        void *data = NULL;
        u16 len = 0;
 
+       if (length > DBGP_REQ_LEN) {
+               if (ctrl->bRequestType == USB_DIR_OUT) {
+                       return err;
+               } else {
+                       /* 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;
+               }
+       }
+
+
        if (request == USB_REQ_GET_DESCRIPTOR) {
                switch (value>>8) {
                case USB_DT_DEVICE:

diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index b95900168a6b1f3b552ea48eb9de360892d8e210..af0b34763326db637758a179918dc002cded5d5e 100644 (file)
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -113,6 +113,8 @@ enum ep0_state {
 /* enough for the whole queue: most events invalidate others */
 #define        N_EVENT                 5
 
+#define RBUF_SIZE              256
+
 struct dev_data {
        spinlock_t                      lock;
        atomic_t                        count;
@@ -146,7 +148,7 @@ struct dev_data {
        struct dentry                   *dentry;
 
        /* except this scratch i/o buffer for ep0 */
-       u8                              rbuf [256];
+       u8                              rbuf[RBUF_SIZE];
 };
 
 static inline void get_dev (struct dev_data *data)
@@ -1332,6 +1334,18 @@ gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
        u16                             w_value = le16_to_cpu(ctrl->wValue);
        u16                             w_length = le16_to_cpu(ctrl->wLength);
 
+       if (w_length > RBUF_SIZE) {
+               if (ctrl->bRequestType == USB_DIR_OUT) {
+                       return value;
+               } else {
+                       /* 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;
+               }
+       }
+
        spin_lock (&dev->lock);
        dev->setup_abort = 0;
        if (dev->state == STATE_DEV_UNCONNECTED) {