From: Antonio Messina <amessina@google.com>
To: unlisted-recipients:; (no To-header on input)
Cc: amessina@google.com, "David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] udp: fix integer overflow while computing available space in sk_rcvbuf
Date: Thu, 19 Dec 2019 15:08:03 +0100 [thread overview]
Message-ID: <20191219140803.135164-1-amessina@google.com> (raw)
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>
---
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 4da5758cc718..93a355b6b092 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1475,7 +1475,7 @@ 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);
--
2.24.1.735.g03f4e72817-goog
next reply other threads:[~2019-12-19 14:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-19 14:08 Antonio Messina [this message]
2019-12-24 22:54 ` [PATCH] udp: fix integer overflow while computing available space in sk_rcvbuf David Miller
2021-11-08 15:44 kaz1020
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