From: Vamsi Krishna Samavedam vskrishn@codeaurora.org
commit a4b98a7512f18534ce33a7e98e49115af59ffa00 upstream.
The function may be unbound causing the ffs_ep and its descriptors to be freed while userspace is in the middle of an ioctl requesting the same descriptors. Avoid dangling pointer reference by first making a local copy of desctiptors before releasing the spinlock.
Fixes: c559a3534109 ("usb: gadget: f_fs: add ioctl returning ep descriptor") Reviewed-by: Peter Chen peter.chen@nxp.com Signed-off-by: Vamsi Krishna Samavedam vskrishn@codeaurora.org Signed-off-by: Jack Pham jackp@codeaurora.org Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/20201130203453.28154-1-jackp@codeaurora.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/gadget/function/f_fs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1328,7 +1328,7 @@ static long ffs_epfile_ioctl(struct file case FUNCTIONFS_ENDPOINT_DESC: { int desc_idx; - struct usb_endpoint_descriptor *desc; + struct usb_endpoint_descriptor desc1, *desc;
switch (epfile->ffs->gadget->speed) { case USB_SPEED_SUPER: @@ -1340,10 +1340,12 @@ static long ffs_epfile_ioctl(struct file default: desc_idx = 0; } + desc = epfile->ep->descs[desc_idx]; + memcpy(&desc1, desc, desc->bLength);
spin_unlock_irq(&epfile->ffs->eps_lock); - ret = copy_to_user((void __user *)value, desc, desc->bLength); + ret = copy_to_user((void __user *)value, &desc1, desc1.bLength); if (ret) ret = -EFAULT; return ret;