tuntap: fix leaking reference count (dd38bd85) · Commits · 戴 / test

Reference count leaking of both module and sock were found: - When a detached file were closed, its sock refcnt from device were not released, solving this by add the sock_put(). - The module were hold or drop unconditionally in TUNSETPERSIST, which means we if we set the persist flag for N times, we need unset it for another N times. Solving this by only hold or drop an reference when there's a flag change and also drop the reference count when the persist device is deleted. Signed-off-by:

Jason Wang <jasowang@redhat.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/tun.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -428,8 +428,10 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
		/* Drop read queue */
		skb_queue_purge(&tfile->sk.sk_receive_queue);
		tun_set_real_num_queues(tun);
		} else if (tfile->detached && clean)
		} else if (tfile->detached && clean) {
		tun = tun_enable_queue(tfile);
		sock_put(&tfile->sk);
		}

		if (clean) {
		if (tun && tun->numqueues == 0 && tun->numdisabled == 0 &&
		@@ -478,6 +480,9 @@ static void tun_detach_all(struct net_device *dev)
		sock_put(&tfile->sk);
		}
		BUG_ON(tun->numdisabled != 0);

		if (tun->flags & TUN_PERSIST)
		module_put(THIS_MODULE);
		}

		static int tun_attach(struct tun_struct tun, struct file file)
		@@ -1874,10 +1879,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
		/* Disable/Enable persist mode. Keep an extra reference to the
		* module to prevent the module being unprobed.
		*/
		if (arg) {
		if (arg && !(tun->flags & TUN_PERSIST)) {
		tun->flags \|= TUN_PERSIST;
		__module_get(THIS_MODULE);
		} else {
		}
		if (!arg && (tun->flags & TUN_PERSIST)) {
		tun->flags &= ~TUN_PERSIST;
		module_put(THIS_MODULE);
		}

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