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Subject[PATCH 4.15 51/64] usb: gadget: f_fs: Use config_ep_by_speed()
Date
4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jack Pham <jackp@codeaurora.org>

commit 675272d092e4a5570bace92593776f7348daf4c5 upstream.

In commit 2bfa0719ac2a ("usb: gadget: function: f_fs: pass
companion descriptor along") there is a pointer arithmetic
bug where the comp_desc is obtained as follows:

comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
USB_DT_ENDPOINT_SIZE);

Since ds is a pointer to usb_endpoint_descriptor, adding
7 to it ends up going out of bounds (7 * sizeof(struct
usb_endpoint_descriptor), which is actually 7*9 bytes) past
the SS descriptor. As a result the maxburst value will be
read incorrectly, and the UDC driver will also get a garbage
comp_desc (assuming it uses it).

Since Felipe wrote, "Eventually, f_fs.c should be converted
to use config_ep_by_speed() like all other functions, though",
let's finally do it. This allows the other usb_ep fields to
be properly populated, such as maxpacket and mult. It also
eliminates the awkward speed-based descriptor lookup since
config_ep_by_speed() does that already using the ones found
in struct usb_function.

Fixes: 2bfa0719ac2a ("usb: gadget: function: f_fs: pass companion descriptor along")
Cc: stable@vger.kernel.org
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/gadget/function/f_fs.c | 38 ++++++-------------------------------
1 file changed, 7 insertions(+), 31 deletions(-)

--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1852,44 +1852,20 @@ static int ffs_func_eps_enable(struct ff

spin_lock_irqsave(&func->ffs->eps_lock, flags);
while(count--) {
- struct usb_endpoint_descriptor *ds;
- struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
- int needs_comp_desc = false;
- int desc_idx;
-
- if (ffs->gadget->speed == USB_SPEED_SUPER) {
- desc_idx = 2;
- needs_comp_desc = true;
- } else if (ffs->gadget->speed == USB_SPEED_HIGH)
- desc_idx = 1;
- else
- desc_idx = 0;
-
- /* fall-back to lower speed if desc missing for current speed */
- do {
- ds = ep->descs[desc_idx];
- } while (!ds && --desc_idx >= 0);
-
- if (!ds) {
- ret = -EINVAL;
- break;
- }
-
ep->ep->driver_data = ep;
- ep->ep->desc = ds;

- if (needs_comp_desc) {
- comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
- USB_DT_ENDPOINT_SIZE);
- ep->ep->maxburst = comp_desc->bMaxBurst + 1;
- ep->ep->comp_desc = comp_desc;
+ ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
+ if (ret) {
+ pr_err("%s: config_ep_by_speed(%s) returned %d\n",
+ __func__, ep->ep->name, ret);
+ break;
}

ret = usb_ep_enable(ep->ep);
if (likely(!ret)) {
epfile->ep = ep;
- epfile->in = usb_endpoint_dir_in(ds);
- epfile->isoc = usb_endpoint_xfer_isoc(ds);
+ epfile->in = usb_endpoint_dir_in(ep->ep->desc);
+ epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
} else {
break;
}

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