path: root/include/net
diff options
authorWillem de Bruijn <willemb@google.com>2020-01-27 15:40:31 -0500
committerDavid S. Miller <davem@davemloft.net>2020-01-28 10:56:51 +0100
commit6cd021a58c18a1731f7e47f83e172c0c302d65e5 (patch)
tree6b69b4a21028a3060fc97ada0491e608e9f73ff8 /include/net
parentnetem: change mailing list (diff)
udp: segment looped gso packets correctly
Multicast and broadcast packets can be looped from egress to ingress pre segmentation with dev_loopback_xmit. That function unconditionally sets ip_summed to CHECKSUM_UNNECESSARY. udp_rcv_segment segments gso packets in the udp rx path. Segmentation usually executes on egress, and does not expect packets of this type. __udp_gso_segment interprets !CHECKSUM_PARTIAL as CHECKSUM_NONE. But the offsets are not correct for gso_make_checksum. UDP GSO packets are of type CHECKSUM_PARTIAL, with their uh->check set to the correct pseudo header checksum. Reset ip_summed to this type. (CHECKSUM_PARTIAL is allowed on ingress, see comments in skbuff.h) Reported-by: syzbot <syzkaller@googlegroups.com> Fixes: cf329aa42b66 ("udp: cope with UDP GRO packet misdirection") Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
1 files changed, 3 insertions, 0 deletions
diff --git a/include/net/udp.h b/include/net/udp.h
index 44e0e52b585c..4a180f2a13e3 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -476,6 +476,9 @@ static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
if (!inet_get_convert_csum(sk))
+ if (skb->pkt_type == PACKET_LOOPBACK)
+ skb->ip_summed = CHECKSUM_PARTIAL;
/* the GSO CB lays after the UDP one, no need to save and restore any
* CB fragment