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Commit 9c79732f authored by Jason Wang's avatar Jason Wang Committed by Greg Kroah-Hartman
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tuntap: fix dividing by zero in ebpf queue selection 



[ 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: default avatarEric Dumazet <eric.dumazet@gmail.com>
Fixes: 96f84061("tun: add eBPF based queue selection method")
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 737713e6

drivers/net/tun.c

+6 −1
Original line number Diff line number Diff line
@@ -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,