tcp: do not drop syn_recv on all icmp reports
Petr Novopashenniy reported that ICMP redirects on SYN_RECV sockets
were leading to RST.
This is of course incorrect.
A specific list of ICMP messages should be able to drop a SYN_RECV.
For instance, a REDIRECT on SYN_RECV shall be ignored, as we do
not hold a dst per SYN_RECV pseudo request.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=111751
Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table")
Reported-by: Petr Novopashenniy <pety@rusnet.ru>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/tcp.h b/include/net/tcp.h
index f6f8f03..ae6468f 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -447,7 +447,7 @@
void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb);
void tcp_v4_mtu_reduced(struct sock *sk);
-void tcp_req_err(struct sock *sk, u32 seq);
+void tcp_req_err(struct sock *sk, u32 seq, bool abort);
int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
struct sock *tcp_create_openreq_child(const struct sock *sk,
struct request_sock *req,
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a4d5237..7f6ff03 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -311,7 +311,7 @@
/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
-void tcp_req_err(struct sock *sk, u32 seq)
+void tcp_req_err(struct sock *sk, u32 seq, bool abort)
{
struct request_sock *req = inet_reqsk(sk);
struct net *net = sock_net(sk);
@@ -323,7 +323,7 @@
if (seq != tcp_rsk(req)->snt_isn) {
NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
- } else {
+ } else if (abort) {
/*
* Still in SYN_RECV, just remove it silently.
* There is no good way to pass the error to the newly
@@ -383,7 +383,12 @@
}
seq = ntohl(th->seq);
if (sk->sk_state == TCP_NEW_SYN_RECV)
- return tcp_req_err(sk, seq);
+ return tcp_req_err(sk, seq,
+ type == ICMP_PARAMETERPROB ||
+ type == ICMP_TIME_EXCEEDED ||
+ (type == ICMP_DEST_UNREACH &&
+ (code == ICMP_NET_UNREACH ||
+ code == ICMP_HOST_UNREACH)));
bh_lock_sock(sk);
/* If too many ICMPs get dropped on busy
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 006396e..1a5a70f 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -327,6 +327,7 @@
struct tcp_sock *tp;
__u32 seq, snd_una;
struct sock *sk;
+ bool fatal;
int err;
sk = __inet6_lookup_established(net, &tcp_hashinfo,
@@ -345,8 +346,9 @@
return;
}
seq = ntohl(th->seq);
+ fatal = icmpv6_err_convert(type, code, &err);
if (sk->sk_state == TCP_NEW_SYN_RECV)
- return tcp_req_err(sk, seq);
+ return tcp_req_err(sk, seq, fatal);
bh_lock_sock(sk);
if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
@@ -400,7 +402,6 @@
goto out;
}
- icmpv6_err_convert(type, code, &err);
/* Might be for an request_sock */
switch (sk->sk_state) {
