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tuntap: fix dividing by zero in ebpf queue selection

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[ Upstream commit a35d310f03a692bf4798eb309a1950a06a150620 ]

We need check if tun->numqueues is zero (e.g for the persist device)
before trying to use it for modular arithmetic.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Fixes: 96f84061620c6("tun: add eBPF based queue selection method")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason Wang 2019-05-08 23:20:17 -04:00 • committed by Greg Kroah-Hartman
parent 737713e6d8
commit 9c79732f98
1 changed files with 6 additions and 1 deletions

7
drivers/net/tun.c
View file

@ -599,13 +599,18 @@ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
{
struct tun_prog *prog;
u32 numqueues;
u16 ret = 0;
numqueues = READ_ONCE(tun->numqueues);
if (!numqueues)
return 0;
prog = rcu_dereference(tun->steering_prog);
if (prog)
ret = bpf_prog_run_clear_cb(prog->prog, skb);
return ret % tun->numqueues;
return ret % numqueues;
}
static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,