diff mbox series

[net,v2,1/2] udp: check encap socket in __udp_lib_err_encap

Message ID 20210716105417.7938-2-vfedorenko@novek.ru
State New
Headers show
Series Fix PMTU for ESP-in-UDP encapsulation | expand

Commit Message

Vadim Fedorenko July 16, 2021, 10:54 a.m. UTC
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>
---
 net/ipv4/udp.c | 23 +++++++++++++++++------
 net/ipv6/udp.c | 23 +++++++++++++++++------
 2 files changed, 34 insertions(+), 12 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 62cd4cd52e84..963275b94f00 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);
@@ -659,12 +661,19 @@  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))
+			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))
@@ -674,6 +683,7 @@  static struct sock *__udp4_lib_err_encap(struct net *net,
 	if (!sk)
 		sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info));
 
+out:
 	skb_set_transport_header(skb, transport_offset);
 	skb_set_network_header(skb, network_offset);
 
@@ -707,15 +717,16 @@  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 0cc7ba531b34..0210ec93d21d 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);
@@ -518,12 +520,19 @@  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))
+			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))
@@ -535,6 +544,7 @@  static struct sock *__udp6_lib_err_encap(struct net *net,
 							offset, info));
 	}
 
+out:
 	skb_set_transport_header(skb, transport_offset);
 	skb_set_network_header(skb, network_offset);
 
@@ -558,16 +568,17 @@  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),