Commit 7063efd3 authored May 16, 2018 by Jason Wang Committed by David S. Miller May 16, 2018

tuntap: fix use after free during release



After commit b196d88a ("tun: fix use after free for ptr_ring") we
need clean up tx ring during release(). But unfortunately, it tries to
do the cleanup blindly after socket were destroyed which will lead
another use-after-free. Fix this by doing the cleanup before dropping
the last reference of the socket in __tun_detach().

Reported-by: Andrei Vagin <avagin@virtuozzo.com>
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
Fixes: b196d88a ("tun: fix use after free for ptr_ring")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent fee8fb95

drivers/net/tun.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -729,6 +729,7 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
	}		}
	if (tun)		if (tun)
	xdp_rxq_info_unreg(&tfile->xdp_rxq);		xdp_rxq_info_unreg(&tfile->xdp_rxq);
			ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
	sock_put(&tfile->sk);		sock_put(&tfile->sk);
	}		}
	}		}
	@@ -3245,7 +3246,6 @@ static int tun_chr_close(struct inode inode, struct file file)
	struct tun_file *tfile = file->private_data;		struct tun_file *tfile = file->private_data;

	tun_detach(tfile, true);		tun_detach(tfile, true);
	ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);

	return 0;		return 0;
	}		}

Admin message