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Subject[PATCH 5.13 131/223] udp: check encap socket in __udp_lib_err
Date
From: Vadim Fedorenko <vfedorenko@novek.ru>

[ Upstream commit 9bfce73c8921c92a9565562e6e7d458d37b7ce80 ]

Commit d26796ae5894 ("udp: check udp sock encap_type in __udp_lib_err")
added checks for encapsulated sockets but it broke cases when there is
no implementation of encap_err_lookup for encapsulation, i.e. ESP in
UDP encapsulation. Fix it by calling encap_err_lookup only if socket
implements this method otherwise treat it as legal socket.

Fixes: d26796ae5894 ("udp: check udp sock encap_type in __udp_lib_err")
Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv4/udp.c | 25 +++++++++++++++++++------
net/ipv6/udp.c | 25 +++++++++++++++++++------
2 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ca9cf1051b1e..568dc31a0467 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -645,10 +645,12 @@ static struct sock *__udp4_lib_err_encap(struct net *net,
const struct iphdr *iph,
struct udphdr *uh,
struct udp_table *udptable,
+ struct sock *sk,
struct sk_buff *skb, u32 info)
{
+ int (*lookup)(struct sock *sk, struct sk_buff *skb);
int network_offset, transport_offset;
- struct sock *sk;
+ struct udp_sock *up;

network_offset = skb_network_offset(skb);
transport_offset = skb_transport_offset(skb);
@@ -659,18 +661,28 @@ static struct sock *__udp4_lib_err_encap(struct net *net,
/* Transport header needs to point to the UDP header */
skb_set_transport_header(skb, iph->ihl << 2);

+ if (sk) {
+ up = udp_sk(sk);
+
+ lookup = READ_ONCE(up->encap_err_lookup);
+ if (lookup && lookup(sk, skb))
+ sk = NULL;
+
+ goto out;
+ }
+
sk = __udp4_lib_lookup(net, iph->daddr, uh->source,
iph->saddr, uh->dest, skb->dev->ifindex, 0,
udptable, NULL);
if (sk) {
- int (*lookup)(struct sock *sk, struct sk_buff *skb);
- struct udp_sock *up = udp_sk(sk);
+ up = udp_sk(sk);

lookup = READ_ONCE(up->encap_err_lookup);
if (!lookup || lookup(sk, skb))
sk = NULL;
}

+out:
if (!sk)
sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info));

@@ -707,15 +719,16 @@ int __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
iph->saddr, uh->source, skb->dev->ifindex,
inet_sdif(skb), udptable, NULL);
+
if (!sk || udp_sk(sk)->encap_type) {
/* No socket for error: try tunnels before discarding */
- sk = ERR_PTR(-ENOENT);
if (static_branch_unlikely(&udp_encap_needed_key)) {
- sk = __udp4_lib_err_encap(net, iph, uh, udptable, skb,
+ sk = __udp4_lib_err_encap(net, iph, uh, udptable, sk, skb,
info);
if (!sk)
return 0;
- }
+ } else
+ sk = ERR_PTR(-ENOENT);

if (IS_ERR(sk)) {
__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 6774e776228c..2d3bd4a9b0d0 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -502,12 +502,14 @@ static struct sock *__udp6_lib_err_encap(struct net *net,
const struct ipv6hdr *hdr, int offset,
struct udphdr *uh,
struct udp_table *udptable,
+ struct sock *sk,
struct sk_buff *skb,
struct inet6_skb_parm *opt,
u8 type, u8 code, __be32 info)
{
+ int (*lookup)(struct sock *sk, struct sk_buff *skb);
int network_offset, transport_offset;
- struct sock *sk;
+ struct udp_sock *up;

network_offset = skb_network_offset(skb);
transport_offset = skb_transport_offset(skb);
@@ -518,18 +520,28 @@ static struct sock *__udp6_lib_err_encap(struct net *net,
/* Transport header needs to point to the UDP header */
skb_set_transport_header(skb, offset);

+ if (sk) {
+ up = udp_sk(sk);
+
+ lookup = READ_ONCE(up->encap_err_lookup);
+ if (lookup && lookup(sk, skb))
+ sk = NULL;
+
+ goto out;
+ }
+
sk = __udp6_lib_lookup(net, &hdr->daddr, uh->source,
&hdr->saddr, uh->dest,
inet6_iif(skb), 0, udptable, skb);
if (sk) {
- int (*lookup)(struct sock *sk, struct sk_buff *skb);
- struct udp_sock *up = udp_sk(sk);
+ up = udp_sk(sk);

lookup = READ_ONCE(up->encap_err_lookup);
if (!lookup || lookup(sk, skb))
sk = NULL;
}

+out:
if (!sk) {
sk = ERR_PTR(__udp6_lib_err_encap_no_sk(skb, opt, type, code,
offset, info));
@@ -558,16 +570,17 @@ int __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,

sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
inet6_iif(skb), inet6_sdif(skb), udptable, NULL);
+
if (!sk || udp_sk(sk)->encap_type) {
/* No socket for error: try tunnels before discarding */
- sk = ERR_PTR(-ENOENT);
if (static_branch_unlikely(&udpv6_encap_needed_key)) {
sk = __udp6_lib_err_encap(net, hdr, offset, uh,
- udptable, skb,
+ udptable, sk, skb,
opt, type, code, info);
if (!sk)
return 0;
- }
+ } else
+ sk = ERR_PTR(-ENOENT);

if (IS_ERR(sk)) {
__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
--
2.30.2


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