Re: [PATCH net v2 1/2] udp: check encap socket in __udp_lib_err_encap
flat view
From: Xin Long <lucien.xin@gmail.com>
Date: 2021-07-16 18:46:34
On Fri, Jul 16, 2021 at 6:54 AM Vadim Fedorenko [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- net/ipv4/udp.c | 23 +++++++++++++++++------ net/ipv6/udp.c | 23 +++++++++++++++++------ 2 files changed, 34 insertions(+), 12 deletions(-)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; + } +
Currently SCTP reuses lookup() to handle some of ICMP error packets by itself
in lookup(), for these packets it will return 1, in which case we should
set sk = NULL, and not let udp4_lib_err() handle these packets again.
Can you change this part to this below?
+ if (sk) {
+ up = udp_sk(sk);
+
+ lookup = READ_ONCE(up->encap_err_lookup);
+ if (lookup && lookup(sk, skb))
+ sk = NULL;
+
+ goto out;
+ }
+
thanks.
quoted hunk ↗ jump to hunk
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), --2.18.4