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RE: [PATCH] usb: gadget: f_fs: report error if excess data received

From Felipe Balbi <felipe.balbi@linux.intel.com>
Newsgroups linux.kernel
Subject RE: [PATCH] usb: gadget: f_fs: report error if excess data received
Date 2016-05-12 11:30 +0200
Message-ID <rxV6q-2GU-3@gated-at.bofh.it> (permalink)
References (3 earlier) <rxSLg-mB-21@gated-at.bofh.it> <rxTnY-13D-27@gated-at.bofh.it> <rxTxD-17U-1@gated-at.bofh.it> <rxU0G-1DT-15@gated-at.bofh.it> <rxUWK-2AG-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Hi again,

Felipe Balbi <felipe.balbi@linux.intel.com> writes:
> @@ -811,7 +815,12 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
>  		 */
>  		ret = interrupted ? -EINTR : ep->status;
>  		if (io_data->read && ret > 0) {
> -			ret = copy_to_iter(data, ret, &io_data->data);
> +			if (ret > io_data->expected_len)
> +				pr_debug("FFS: size mismatch: %zd for %zd",
> +						ret, io_data->expected_len);
> +
> +			ret = copy_to_iter(data, io_data->expected_len,
> +					&io_data->data);

we need a min() here. Better version below:

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 73515d54e1cc..6c49b152f46e 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -156,6 +156,8 @@ struct ffs_io_data {
 	struct usb_request *req;
 
 	struct ffs_data *ffs;
+
+	ssize_t expected_len;
 };
 
 struct ffs_desc_helper {
@@ -730,8 +732,10 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 		 * Controller may require buffer size to be aligned to
 		 * maxpacketsize of an out endpoint.
 		 */
-		if (io_data->read)
+		if (io_data->read) {
+			io_data->expected_len = data_len;
 			data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
+		}
 		spin_unlock_irq(&epfile->ffs->eps_lock);
 
 		data = kmalloc(data_len, GFP_KERNEL);
@@ -811,7 +815,15 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 		 */
 		ret = interrupted ? -EINTR : ep->status;
 		if (io_data->read && ret > 0) {
-			ret = copy_to_iter(data, ret, &io_data->data);
+			ssize_t bytes;
+
+			if (ret > io_data->expected_len)
+				pr_debug("FFS: size mismatch: %zd for %zd",
+						ret, io_data->expected_len);
+
+			bytes = min(ret, io_data->expected_len);
+
+			ret = copy_to_iter(data, bytes, &io_data->data);
 			if (!ret)
 				ret = -EFAULT;
 		}


-- 
balbi

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[PATCH] usb: gadget: f_fs: report error if excess data received changbin.du@intel.com - 2016-05-11 12:40 +0200
  Re: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <balbi@kernel.org> - 2016-05-11 13:10 +0200
    Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-11 14:40 +0200
      RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-12 06:30 +0200
    RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-12 06:30 +0200
      RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <balbi@kernel.org> - 2016-05-12 09:00 +0200
        RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-12 09:40 +0200
          RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-12 09:50 +0200
            RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-12 10:20 +0200
              RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-12 11:20 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-12 11:30 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-12 12:00 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-12 11:50 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-12 12:20 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-12 12:20 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-12 12:50 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-12 13:30 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-13 08:00 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-13 08:40 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-13 12:40 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received Alan Stern <stern@rowland.harvard.edu> - 2016-05-13 16:30 +0200
                Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-14 22:40 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-16 15:10 +0200
                Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-16 15:10 +0200
                Re: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-16 15:20 +0200
                Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-16 21:10 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-17 05:00 +0200
                Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-18 11:50 +0200
                Re: [PATCH] usb: gadget: f_fs: report error if excess data received Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-05-18 12:20 +0200
                Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-18 15:40 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-19 05:00 +0200
                Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-19 09:40 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-19 11:00 +0200
                RE: [PATCH] usb: gadget: f_fs: report error if excess data received "Du, Changbin" <changbin.du@intel.com> - 2016-05-19 04:40 +0200
  Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-16 18:10 +0200
    Re: [PATCH] usb: gadget: f_fs: report error if excess data received Lars-Peter Clausen <lars@metafoo.de> - 2016-05-16 18:30 +0200
      Re: [PATCH] usb: gadget: f_fs: report error if excess data received Michal Nazarewicz <mina86@mina86.com> - 2016-05-16 18:50 +0200
    Re: [PATCH] usb: gadget: f_fs: report error if excess data received Krzysztof Opasiak <k.opasiak@samsung.com> - 2016-05-16 18:40 +0200

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