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usb: gadget: f_fs: Use config_ep_by_speed() 

In commit 2bfa0719ac ("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: 2bfa0719ac ("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>
This commit is contained in:
Jack Pham 2018-01-24 23:58:20 -08:00 committed by Felipe Balbi
parent 6cf439e0d3
commit 675272d092
1 changed files with 7 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
drivers/usb/gadget/function/f_fs.c
View File

@ -1855,44 +1855,20 @@ static int ffs_func_eps_enable(struct ffs_function *func)
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;
}