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usb: gadget: f_fs: Use local copy of descriptors for userspace copy
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: c559a35341
("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>
This commit is contained in:
parent
45c5775460
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@ -1324,7 +1324,7 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code,
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case FUNCTIONFS_ENDPOINT_DESC:
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{
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int desc_idx;
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struct usb_endpoint_descriptor *desc;
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struct usb_endpoint_descriptor desc1, *desc;
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switch (epfile->ffs->gadget->speed) {
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case USB_SPEED_SUPER:
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@ -1336,10 +1336,12 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code,
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default:
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desc_idx = 0;
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}
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desc = epfile->ep->descs[desc_idx];
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memcpy(&desc1, desc, desc->bLength);
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spin_unlock_irq(&epfile->ffs->eps_lock);
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ret = copy_to_user((void __user *)value, desc, desc->bLength);
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ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
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if (ret)
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ret = -EFAULT;
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return ret;
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