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authorMichal Kubeček <mkubecek@suse.cz>2016-07-08 17:52:33 +0200
committerDavid S. Miller <davem@davemloft.net>2016-07-11 12:43:15 -0700
commita612769774a30e4fc143c4cb6395c12573415660 (patch)
tree6d8340d073fd7465158f130e1bbe23429956f3b0 /net
parentf3ea3119ad75dde0ba3e8da4653dbd5a189688e5 (diff)
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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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/udp.c2
-rw-r--r--net/ipv6/udp.c2
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)) {