From 4df0bfc79904b7169dc77dcce44598b1545721f9 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Mon, 15 Jan 2018 11:37:29 -0800 Subject: [PATCH] tun: fix a memory leak for tfile->tx_array tfile->tun could be detached before we close the tun fd, via tun_detach_all(), so it should not be used to check for tfile->tx_array. As Jason suggested, we probably have to clean it up unconditionally both in __tun_deatch() and tun_detach_all(), but this requires to check if it is initialized or not. Currently skb_array_cleanup() doesn't have such a check, so I check it in the caller and introduce a helper function, it is a bit ugly but we can always improve it in net-next. Reported-by: Dmitry Vyukov Fixes: 1576d9860599 ("tun: switch to use skb array for tx") Cc: Jason Wang Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 4f4a842a1c9c..a8ec589d1359 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -611,6 +611,14 @@ static void tun_queue_purge(struct tun_file *tfile) skb_queue_purge(&tfile->sk.sk_error_queue); } +static void tun_cleanup_tx_array(struct tun_file *tfile) +{ + if (tfile->tx_array.ring.queue) { + skb_array_cleanup(&tfile->tx_array); + memset(&tfile->tx_array, 0, sizeof(tfile->tx_array)); + } +} + static void __tun_detach(struct tun_file *tfile, bool clean) { struct tun_file *ntfile; @@ -657,8 +665,7 @@ static void __tun_detach(struct tun_file *tfile, bool clean) tun->dev->reg_state == NETREG_REGISTERED) unregister_netdevice(tun->dev); } - if (tun) - skb_array_cleanup(&tfile->tx_array); + tun_cleanup_tx_array(tfile); sock_put(&tfile->sk); } } @@ -700,11 +707,13 @@ static void tun_detach_all(struct net_device *dev) /* Drop read queue */ tun_queue_purge(tfile); sock_put(&tfile->sk); + tun_cleanup_tx_array(tfile); } list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { tun_enable_queue(tfile); tun_queue_purge(tfile); sock_put(&tfile->sk); + tun_cleanup_tx_array(tfile); } BUG_ON(tun->numdisabled != 0); @@ -2851,6 +2860,8 @@ static int tun_chr_open(struct inode *inode, struct file * file) sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); + memset(&tfile->tx_array, 0, sizeof(tfile->tx_array)); + return 0; }