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authorJesper Dangaard Brouer <hawk@comx.dk>2009-02-05 15:05:45 -0800
committerDavid S. Miller <davem@davemloft.net>2009-02-05 15:05:45 -0800
commit7b5e56f9d635643ad54f2f42e69ad16b80a2cff1 (patch)
treef0e3d35d01047375ea2eef5f8c99d9b96bc919ab /net
parentb98ac702f49042ab0c382b839465b95a2bd0cd65 (diff)
downloadlinux-2.6.38-lt-ux500-7b5e56f9d635643ad54f2f42e69ad16b80a2cff1.tar.gz
udp: Fix UDP short packet false positive
The UDP header pointer assignment must happen after calling pskb_may_pull(). As pskb_may_pull() can potentially alter the SKB buffer. This was exposted by running multicast traffic through the NIU driver, as it won't prepull the protocol headers into the linear area on receive. Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/udp.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 1ab180bad72..cc3a0a06c00 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1231,7 +1231,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
int proto)
{
struct sock *sk;
- struct udphdr *uh = udp_hdr(skb);
+ struct udphdr *uh;
unsigned short ulen;
struct rtable *rt = (struct rtable*)skb->dst;
__be32 saddr = ip_hdr(skb)->saddr;
@@ -1244,6 +1244,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto drop; /* No space for header. */
+ uh = udp_hdr(skb);
ulen = ntohs(uh->len);
if (ulen > skb->len)
goto short_packet;