ipv4: udp: fix short packet and bad checksum logging

commit ccc2d97cb7c798e785c9f198de243e2b59f7073b upstream.

commit 2783ef23 moved the initialisation of saddr and daddr after
pskb_may_pull() to avoid a potential data corruption.  Unfortunately
also placing it after the short packet and bad checksum error paths,
where these variables are used for logging.  The result is bogus
output like

[92238.389505] UDP: short packet: From 2.0.0.0:65535 23715/178 to 0.0.0.0:65535

Moving the saddr and daddr initialisation above the error paths, while still
keeping it after the pskb_may_pull() to keep the fix from commit 2783ef23.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 16190cac0b69..955f0b2c9c16 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1527,6 +1527,9 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 
         uh   = udp_hdr(skb);
         ulen = ntohs(uh->len);
+        saddr = ip_hdr(skb)->saddr;
+        daddr = ip_hdr(skb)->daddr;
+
         if (ulen > skb->len)
                 goto short_packet;
 
@@ -1540,9 +1543,6 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
         if (udp4_csum_init(skb, uh, proto))
                 goto csum_error;
 
-        saddr = ip_hdr(skb)->saddr;
-        daddr = ip_hdr(skb)->daddr;
-
         if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
                 return __udp4_lib_mcast_deliver(net, skb, uh,
                                 saddr, daddr, udptable);