[PATCH 5.10 118/120] udp: ipv4: manipulate network header of NATed UDP GRO fraglist

Greg Kroah-Hartman
2021-02-08T17:53:25Z

From: Dongseok Yi <dseok.yi@samsung.com>

commit c3df39ac9b0e3747bf8233ea9ce4ed5ceb3199d3 upstream.

UDP/IP header of UDP GROed frag_skbs are not updated even after NAT
forwarding. Only the header of head_skb from ip_finish_output_gso ->
skb_gso_segment is updated but following frag_skbs are not updated.

A call path skb_mac_gso_segment -> inet_gso_segment ->
udp4_ufo_fragment -> __udp_gso_segment -> __udp_gso_segment_list
does not try to update UDP/IP header of the segment list but copy
only the MAC header.

Update port, addr and check of each skb of the segment list in
__udp_gso_segment_list. It covers both SNAT and DNAT.

Fixes: 9fd1ff5d2ac7 (udp: Support UDP fraglist GRO/GSO.)
Signed-off-by: Dongseok Yi <dseok.yi@samsung.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Link: https://lore.kernel.org/r/1611962007-80092-1-git-send-email-dseok.yi@samsung.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/udp.h | 2 -
net/ipv4/udp_offload.c | 69 +++++++++++++++++++++++++++++++++++++++++++++----
net/ipv6/udp_offload.c | 2 -
3 files changed, 66 insertions(+), 7 deletions(-)

--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -178,7 +178,7 @@ struct sk_buff *udp_gro_receive(struct l
int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);

struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
- netdev_features_t features);
+ netdev_features_t features, bool is_ipv6);

static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
{
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -184,8 +184,67 @@ out_unlock:
}
EXPORT_SYMBOL(skb_udp_tunnel_segment);

+static void __udpv4_gso_segment_csum(struct sk_buff *seg,
+ __be32 *oldip, __be32 *newip,
+ __be16 *oldport, __be16 *newport)
+{
+ struct udphdr *uh;
+ struct iphdr *iph;
+
+ if (*oldip == *newip && *oldport == *newport)
+ return;
+
+ uh = udp_hdr(seg);
+ iph = ip_hdr(seg);
+
+ if (uh->check) {
+ inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
+ true);
+ inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
+ false);
+ if (!uh->check)
+ uh->check = CSUM_MANGLED_0;
+ }
+ *oldport = *newport;
+
+ csum_replace4(&iph->check, *oldip, *newip);
+ *oldip = *newip;
+}
+
+static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
+{
+ struct sk_buff *seg;
+ struct udphdr *uh, *uh2;
+ struct iphdr *iph, *iph2;
+
+ seg = segs;
+ uh = udp_hdr(seg);
+ iph = ip_hdr(seg);
+
+ if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
+ (udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
+ (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
+ (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
+ return segs;
+
+ while ((seg = seg->next)) {
+ uh2 = udp_hdr(seg);
+ iph2 = ip_hdr(seg);
+
+ __udpv4_gso_segment_csum(seg,
+ &iph2->saddr, &iph->saddr,
+ &uh2->source, &uh->source);
+ __udpv4_gso_segment_csum(seg,
+ &iph2->daddr, &iph->daddr,
+ &uh2->dest, &uh->dest);
+ }
+
+ return segs;
+}
+
static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
- netdev_features_t features)
+ netdev_features_t features,
+ bool is_ipv6)
{
unsigned int mss = skb_shinfo(skb)->gso_size;

@@ -195,11 +254,11 @@ static struct sk_buff *__udp_gso_segment

udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);

- return skb;
+ return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);
}

struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
- netdev_features_t features)
+ netdev_features_t features, bool is_ipv6)
{
struct sock *sk = gso_skb->sk;
unsigned int sum_truesize = 0;
@@ -211,7 +270,7 @@ struct sk_buff *__udp_gso_segment(struct
__be16 newlen;

if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
- return __udp_gso_segment_list(gso_skb, features);
+ return __udp_gso_segment_list(gso_skb, features, is_ipv6);

mss = skb_shinfo(gso_skb)->gso_size;
if (gso_skb->len <= sizeof(*uh) + mss)
@@ -325,7 +384,7 @@ static struct sk_buff *udp4_ufo_fragment
goto out;

if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
- return __udp_gso_segment(skb, features);
+ return __udp_gso_segment(skb, features, false);

mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -46,7 +46,7 @@ static struct sk_buff *udp6_ufo_fragment
goto out;

if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
- return __udp_gso_segment(skb, features);
+ return __udp_gso_segment(skb, features, true);

/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
* do checksum of UDP packets sent as multiple IP fragments.