From: Antonio Messina amessina@google.com
[ Upstream commit feed8a4fc9d46c3126fb9fcae0e9248270c6321a ]
When the size of the receive buffer for a socket is close to 2^31 when computing if we have enough space in the buffer to copy a packet from the queue to the buffer we might hit an integer overflow.
When an user set net.core.rmem_default to a value close to 2^31 UDP packets are dropped because of this overflow. This can be visible, for instance, with failure to resolve hostnames.
This can be fixed by casting sk_rcvbuf (which is an int) to unsigned int, similarly to how it is done in TCP.
Signed-off-by: Antonio Messina amessina@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/ipv4/udp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index adecbe2..43e72e6 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1409,7 +1409,7 @@ int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb) * queue contains some other skb */ rmem = atomic_add_return(size, &sk->sk_rmem_alloc); - if (rmem > (size + sk->sk_rcvbuf)) + if (rmem > (size + (unsigned int)sk->sk_rcvbuf)) goto uncharge_drop;
spin_lock(&list->lock);