From 0e1d6eca5113858ed2caea61a5adc03c595f6096 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 2 Oct 2018 15:47:35 -0700 Subject: [PATCH] rtnl: limit IFLA_NUM_TX_QUEUES and IFLA_NUM_RX_QUEUES to 4096 We have an impressive number of syzkaller bugs that are linked to the fact that syzbot was able to create a networking device with millions of TX (or RX) queues. Let's limit the number of RX/TX queues to 4096, this really should cover all known cases. A separate patch will add various cond_resched() in the loops handling sysfs entries at device creation and dismantle. Tested: lpaa6:~# ip link add gre-4097 numtxqueues 4097 numrxqueues 4097 type ip6gretap RTNETLINK answers: Invalid argument lpaa6:~# time ip link add gre-4096 numtxqueues 4096 numrxqueues 4096 type ip6gretap real 0m0.180s user 0m0.000s sys 0m0.107s Fixes: 76ff5cc91935 ("rtnl: allow to specify number of rx and tx queues on device creation") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller --- net/core/rtnetlink.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 7f37fe9c65a5..448703312fed 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2835,6 +2835,12 @@ struct net_device *rtnl_create_link(struct net *net, else if (ops->get_num_rx_queues) num_rx_queues = ops->get_num_rx_queues(); + if (num_tx_queues < 1 || num_tx_queues > 4096) + return ERR_PTR(-EINVAL); + + if (num_rx_queues < 1 || num_rx_queues > 4096) + return ERR_PTR(-EINVAL); + dev = alloc_netdev_mqs(ops->priv_size, ifname, name_assign_type, ops->setup, num_tx_queues, num_rx_queues); if (!dev) -- 2.30.2