Commit 5b5a979c authored by Fei Yang's avatar Fei Yang Committed by Greg Kroah-Hartman

usb: gadget: f_fs: data_len used before properly set

commit 4833a94e upstream.

The following line of code in function ffs_epfile_io is trying to set
flag io_data->use_sg in case buffer required is larger than one page.

    io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;

However at this point of time the variable data_len has not been set
to the proper buffer size yet. The consequence is that io_data->use_sg
is always set regardless what buffer size really is, because the condition
(data_len > PAGE_SIZE) is effectively an unsigned comparison between
-EINVAL and PAGE_SIZE which would always result in TRUE.

Fixes: 772a7a72 ("usb: gadget: f_fs: Allow scatter-gather buffers")
Signed-off-by: default avatarFei Yang <fei.yang@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cae92869
......@@ -997,7 +997,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
* earlier
*/
gadget = epfile->ffs->gadget;
io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
spin_lock_irq(&epfile->ffs->eps_lock);
/* In the meantime, endpoint got disabled or changed. */
......@@ -1012,6 +1011,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
*/
if (io_data->read)
data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
spin_unlock_irq(&epfile->ffs->eps_lock);
data = ffs_alloc_buffer(io_data, data_len);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment