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Commit 65745422 authored by Amit Shah's avatar Amit Shah Committed by Rusty Russell
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virtio: console: Prevent userspace from submitting NULL buffers 



A userspace could submit a buffer with 0 length to be written to the
host.  Prevent such a situation.

This was not needed previously, but recent changes in the way write()
works exposed this condition to trigger a virtqueue event to the host,
causing a NULL buffer to be sent across.

Signed-off-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
CC: stable@kernel.org
parent 6df7aadc

drivers/char/virtio_console.c

+4 −0
Original line number Diff line number Diff line
@@ -596,6 +596,10 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, 
	ssize_t ret;

	bool nonblock;



	/* Userspace could be out to fool us */

	if (!count)

		return 0;



	port = filp->private_data;



	nonblock = filp->f_flags & O_NONBLOCK;