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tcp: do not drop syn_recv on all icmp reports

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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: 079096f103 ("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>
This commit is contained in:
Eric Dumazet 2016-02-02 19:31:12 -08:00 committed by David S. Miller
parent 44c3d0c1c0
commit 9cf7490360
3 changed files with 12 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/tcp.h
View File

@ -447,7 +447,7 @@ const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
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,

11
net/ipv4/tcp_ipv4.c
View File

@ -311,7 +311,7 @@ static void do_redirect(struct sk_buff *skb, struct sock *sk)
/* 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 @@ void tcp_req_err(struct sock *sk, u32 seq)
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 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
}
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

5
net/ipv6/tcp_ipv6.c
View File

@ -327,6 +327,7 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
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 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
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 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
goto out;
}
icmpv6_err_convert(type, code, &err);
/* Might be for an request_sock */
switch (sk->sk_state) {