Setup partial checksum and add gso checks to handle large UFO packets from
untrusted sources.
Signed-off-by: Sridhar Samudrala <sri@xxxxxxxxxx>
---
include/net/udp.h | 3 +++
net/ipv4/af_inet.c | 2 ++
net/ipv4/udp.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++
net/ipv6/udp.c | 22 +++++++++++++++++++
4 files changed, 87 insertions(+), 0 deletions(-)
diff --git a/include/net/udp.h b/include/net/udp.h
index 90e6ce5..274b764 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -207,4 +207,7 @@ extern void udp4_proc_exit(void);
#endif
extern void udp_init(void);
+
+extern int udp_v4_gso_send_check(struct sk_buff *skb);
+extern struct sk_buff *udp_ufo_fragment(struct sk_buff *skb, int features);
#endif /* _UDP_H */
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index d873621..1c1ac7d 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1426,6 +1426,8 @@ static struct net_protocol tcp_protocol = {
static struct net_protocol udp_protocol = {
.handler = udp_rcv,
.err_handler = udp_err,
+ .gso_send_check = udp_v4_gso_send_check,
+ .gso_segment = udp_ufo_fragment,
.no_policy = 1,
.netns_ok = 1,
};
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 8f4158d..678bdf9 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1815,6 +1815,66 @@ void __init udp_init(void)
sysctl_udp_wmem_min = SK_MEM_QUANTUM;
}
+int udp_v4_gso_send_check(struct sk_buff *skb)
+{
+ const struct iphdr *iph;
+ struct udphdr *uh;
+
+ if (!pskb_may_pull(skb, sizeof(*uh)))
+ return -EINVAL;
+
+ iph = ip_hdr(skb);
+ uh = udp_hdr(skb);
+
+ uh->check = 0;
+ uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len, IPPROTO_UDP, 0);
+ skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ return 0;
+}
+
+struct sk_buff *udp_ufo_fragment(struct sk_buff *skb, int features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ struct udphdr *uh;
+ unsigned uhlen;
+ unsigned int mss;
+
+ if (!pskb_may_pull(skb, sizeof(*uh)))
+ goto out;
+
+ uh = udp_hdr(skb);
+ uhlen = sizeof(*uh);
+
+ __skb_pull(skb, uhlen);
+
+ mss = skb_shinfo(skb)->gso_size;
+ if (unlikely(skb->len <= mss))
+ goto out;
+
+ if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
+ int type = skb_shinfo(skb)->gso_type;
+
+ if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
+ !(type & (SKB_GSO_UDP))))
+ goto out;
+
+ skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
+
+ segs = NULL;
+ goto out;
+ }
+
+ /* Software UFO is not yet supported */
+ segs = ERR_PTR(-EPROTONOSUPPORT);
+
+out:
+ return segs;
+}
+EXPORT_SYMBOL(udp_ufo_fragment);
+
+
EXPORT_SYMBOL(udp_disconnect);
EXPORT_SYMBOL(udp_ioctl);
EXPORT_SYMBOL(udp_prot);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index fad0f5f..ccd42d5 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1081,9 +1081,31 @@ int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
}
#endif
+
+static int udpv6_gso_send_check(struct sk_buff *skb)
+{
+ struct ipv6hdr *ipv6h;
+ struct udphdr *uh;
+
+ if (!pskb_may_pull(skb, sizeof(*uh)))
+ return -EINVAL;
+
+ ipv6h = ipv6_hdr(skb);
+ uh = udp_hdr(skb);
+
+ uh->check = 0;
+ uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len, IPPROTO_UDP, 0);
+ skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ return 0;
+}
+
static struct inet6_protocol udpv6_protocol = {
.handler = udpv6_rcv,
.err_handler = udpv6_err,
+ .gso_send_check = udpv6_gso_send_check,
+ .gso_segment = udp_ufo_fragment,
.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};
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