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| author | Michal Kubeček <mkubecek@suse.cz> | 2016-07-08 17:52:33 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-07-11 12:43:15 -0700 |
| commit | a612769774a30e4fc143c4cb6395c12573415660 (patch) | |
| tree | 6d8340d073fd7465158f130e1bbe23429956f3b0 | |
| parent | f3ea3119ad75dde0ba3e8da4653dbd5a189688e5 (diff) | |
| download | linux-stable-a612769774a30e4fc143c4cb6395c12573415660.tar.gz linux-stable-a612769774a30e4fc143c4cb6395c12573415660.tar.bz2 linux-stable-a612769774a30e4fc143c4cb6395c12573415660.zip | |
udp: prevent bugcheck if filter truncates packet too much
If socket filter truncates an udp packet below the length of UDP header
in udpv6_queue_rcv_skb() or udp_queue_rcv_skb(), it will trigger a
BUG_ON in skb_pull_rcsum(). This BUG_ON (and therefore a system crash if
kernel is configured that way) can be easily enforced by an unprivileged
user which was reported as CVE-2016-6162. For a reproducer, see
http://seclists.org/oss-sec/2016/q3/8
Fixes: e6afc8ace6dd ("udp: remove headers from UDP packets before queueing")
Reported-by: Marco Grassi <marco.gra@gmail.com>
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/udp.c | 2 | ||||
| -rw-r--r-- | net/ipv6/udp.c | 2 |
2 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index ca5e8ea29538..4aed8fc23d32 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1583,6 +1583,8 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) if (sk_filter(sk, skb)) goto drop; + if (unlikely(skb->len < sizeof(struct udphdr))) + goto drop; udp_csum_pull_header(skb); if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) { diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 005dc82c2138..acc09705618b 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -620,6 +620,8 @@ int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) if (sk_filter(sk, skb)) goto drop; + if (unlikely(skb->len < sizeof(struct udphdr))) + goto drop; udp_csum_pull_header(skb); if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) { |