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authorWillem de Bruijn <willemb@google.com>2017-08-10 12:29:19 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-12 19:34:27 -0700
commit2a8c396a689114da0fb9164cd07b13fd5b800782 (patch)
tree655be1cc8a5b41786af722a3417bbb5d46a87b50
parent2b5e5a8d94853d6f6d461d6c6b7a87921adfcebd (diff)
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udp: consistently apply ufo or fragmentation
[ Upstream commit 85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa ] When iteratively building a UDP datagram with MSG_MORE and that datagram exceeds MTU, consistently choose UFO or fragmentation. Once skb_is_gso, always apply ufo. Conversely, once a datagram is split across multiple skbs, do not consider ufo. Sendpage already maintains the first invariant, only add the second. IPv6 does not have a sendpage implementation to modify. A gso skb must have a partial checksum, do not follow sk_no_check_tx in udp_send_skb. Found by syzkaller. Fixes: e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach") Reported-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ipv4/ip_output.c8
-rw-r--r--net/ipv4/udp.c2
-rw-r--r--net/ipv6/ip6_output.c7
3 files changed, 10 insertions, 7 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 532b36e9ce2a..e5948c0c9759 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -964,11 +964,12 @@ static int __ip_append_data(struct sock *sk,
csummode = CHECKSUM_PARTIAL;
cork->length += length;
- if ((((length + (skb ? skb->len : fragheaderlen)) > mtu) ||
- (skb && skb_is_gso(skb))) &&
+ if ((skb && skb_is_gso(skb)) ||
+ (((length + (skb ? skb->len : fragheaderlen)) > mtu) &&
+ (skb_queue_len(queue) <= 1) &&
(sk->sk_protocol == IPPROTO_UDP) &&
(rt->dst.dev->features & NETIF_F_UFO) && !dst_xfrm(&rt->dst) &&
- (sk->sk_type == SOCK_DGRAM) && !sk->sk_no_check_tx) {
+ (sk->sk_type == SOCK_DGRAM) && !sk->sk_no_check_tx)) {
err = ip_ufo_append_data(sk, queue, getfrag, from, length,
hh_len, fragheaderlen, transhdrlen,
maxfraglen, flags);
@@ -1287,6 +1288,7 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
return -EINVAL;
if ((size + skb->len > mtu) &&
+ (skb_queue_len(&sk->sk_write_queue) == 1) &&
(sk->sk_protocol == IPPROTO_UDP) &&
(rt->dst.dev->features & NETIF_F_UFO)) {
if (skb->ip_summed != CHECKSUM_PARTIAL)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index b9a84eba60b8..c991b97cbb28 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -802,7 +802,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
if (is_udplite) /* UDP-Lite */
csum = udplite_csum(skb);
- else if (sk->sk_no_check_tx) { /* UDP csum disabled */
+ else if (sk->sk_no_check_tx && !skb_is_gso(skb)) { /* UDP csum off */
skb->ip_summed = CHECKSUM_NONE;
goto send;
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index be0306778938..365d5108a326 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1386,11 +1386,12 @@ emsgsize:
*/
cork->length += length;
- if ((((length + (skb ? skb->len : headersize)) > mtu) ||
- (skb && skb_is_gso(skb))) &&
+ if ((skb && skb_is_gso(skb)) ||
+ (((length + (skb ? skb->len : headersize)) > mtu) &&
+ (skb_queue_len(queue) <= 1) &&
(sk->sk_protocol == IPPROTO_UDP) &&
(rt->dst.dev->features & NETIF_F_UFO) && !dst_xfrm(&rt->dst) &&
- (sk->sk_type == SOCK_DGRAM) && !udp_get_no_check6_tx(sk)) {
+ (sk->sk_type == SOCK_DGRAM) && !udp_get_no_check6_tx(sk))) {
err = ip6_ufo_append_data(sk, queue, getfrag, from, length,
hh_len, fragheaderlen, exthdrlen,
transhdrlen, mtu, flags, fl6);