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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 19:24:19 -0700
commit4ac8dc208caf85675f0f745783e0a3f88dac0008 (patch)
tree2641eb342bfd7674f3aa83880fcb0fab62a64163
parentddc3da581617b98832e5d108a95f1face998b618 (diff)
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. [gregkh - tweaks for 3.18 for ipv6, hopefully they are correct...] 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.c7
-rw-r--r--net/ipv4/udp.c2
-rw-r--r--net/ipv6/ip6_output.c7
3 files changed, 10 insertions, 6 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 357c2a914e77..928753320632 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -888,10 +888,12 @@ static int __ip_append_data(struct sock *sk,
csummode = CHECKSUM_PARTIAL;
cork->length += length;
- if (((length > mtu) || (skb && skb_is_gso(skb))) &&
+ if ((skb && skb_is_gso(skb)) ||
+ ((length > mtu) &&
+ (skb_queue_len(queue) <= 1) &&
(sk->sk_protocol == IPPROTO_UDP) &&
(rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len &&
- (sk->sk_type == SOCK_DGRAM)) {
+ (sk->sk_type == SOCK_DGRAM))) {
err = ip_ufo_append_data(sk, queue, getfrag, from, length,
hh_len, fragheaderlen, transhdrlen,
maxfraglen, flags);
@@ -1207,6 +1209,7 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
cork->length += size;
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)) {
skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ee26711a952a..085fd0d357e2 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -804,7 +804,7 @@ 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 650e7c53c3c8..f71de459139f 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1305,11 +1305,12 @@ emsgsize:
skb = skb_peek_tail(&sk->sk_write_queue);
cork->length += length;
- if ((((length + fragheaderlen) > mtu) ||
- (skb && skb_is_gso(skb))) &&
+ if ((skb && skb_is_gso(skb)) ||
+ (((length + fragheaderlen) > mtu) &&
+ (skb_queue_len(&sk->sk_write_queue) <= 1) &&
(sk->sk_protocol == IPPROTO_UDP) &&
(rt->dst.dev->features & NETIF_F_UFO) &&
- (sk->sk_type == SOCK_DGRAM)) {
+ (sk->sk_type == SOCK_DGRAM))) {
err = ip6_ufo_append_data(sk, getfrag, from, length,
hh_len, fragheaderlen,
transhdrlen, mtu, flags, rt);