Revert "tcp: resolve KABI broken when fix CVE-2019-11478 and CVE-2019-11479"

hulk inclusion
category: bugfix
bugzilla: 16585
CVE: NA

-------------------------------------------------

This patch is not needed in next branch.
This reverts commit 54613bb66ec685fb8a1c16f56eccbc143d686a35.

include/net/netns/ipv4.h

@@ -117,6 +117,7 @@ struct netns_ipv4 {
 #endif
 	int sysctl_tcp_mtu_probing;
 	int sysctl_tcp_base_mss;
+	int sysctl_tcp_min_snd_mss;
 	int sysctl_tcp_probe_threshold;
 	u32 sysctl_tcp_probe_interval;
 

include/net/tcp.h

@@ -245,7 +245,6 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
 /* sysctl variables for tcp */
 extern int sysctl_tcp_max_orphans;
 extern long sysctl_tcp_mem[3];
-extern int sysctl_tcp_min_snd_mss;
 
 #define TCP_RACK_LOSS_DETECTION  0x1 /* Use RACK to detect losses */
 #define TCP_RACK_STATIC_REO_WND  0x2 /* Use static RACK reo wnd */

include/uapi/linux/snmp.h

@@ -282,6 +282,7 @@ enum
 	LINUX_MIB_TCPACKCOMPRESSED,		/* TCPAckCompressed */
 	LINUX_MIB_TCPZEROWINDOWDROP,		/* TCPZeroWindowDrop */
 	LINUX_MIB_TCPRCVQDROP,			/* TCPRcvQDrop */
+	LINUX_MIB_TCPWQUEUETOOBIG,		/* TCPWqueueTooBig */
 	__LINUX_MIB_MAX
 };
 

net/ipv4/proc.c

@@ -290,6 +290,7 @@ static const struct snmp_mib snmp4_net_list[] = {
 	SNMP_MIB_ITEM("TCPAckCompressed", LINUX_MIB_TCPACKCOMPRESSED),
 	SNMP_MIB_ITEM("TCPZeroWindowDrop", LINUX_MIB_TCPZEROWINDOWDROP),
 	SNMP_MIB_ITEM("TCPRcvQDrop", LINUX_MIB_TCPRCVQDROP),
+	SNMP_MIB_ITEM("TCPWqueueTooBig", LINUX_MIB_TCPWQUEUETOOBIG),
 	SNMP_MIB_SENTINEL
 };
 

net/ipv4/sysctl_net_ipv4.c

@@ -752,7 +752,7 @@ static struct ctl_table ipv4_net_table[] = {
 	},
 	{
 		.procname	= "tcp_min_snd_mss",
-		.data		= &sysctl_tcp_min_snd_mss,
+		.data		= &init_net.ipv4.sysctl_tcp_min_snd_mss,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,

net/ipv4/tcp_ipv4.c

@@ -92,8 +92,6 @@ static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
 			       __be32 daddr, __be32 saddr, const struct tcphdr *th);
 #endif
 
-int sysctl_tcp_min_snd_mss __read_mostly = TCP_MIN_SND_MSS;
-
 struct inet_hashinfo tcp_hashinfo;
 EXPORT_SYMBOL(tcp_hashinfo);
 
@@ -2529,6 +2527,7 @@ static int __net_init tcp_sk_init(struct net *net)
 	net->ipv4.sysctl_tcp_ecn_fallback = 1;
 
 	net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
+	net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
 	net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
 	net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
 

net/ipv4/tcp_output.c

@@ -1299,8 +1299,10 @@ int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
 	if (nsize < 0)
 		nsize = 0;
 
-	if (unlikely((sk->sk_wmem_queued >> 1) > sk->sk_sndbuf))
+	if (unlikely((sk->sk_wmem_queued >> 1) > sk->sk_sndbuf)) {
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPWQUEUETOOBIG);
 		return -ENOMEM;
+	}
 
 	if (skb_unclone(skb, gfp))
 		return -ENOMEM;
@@ -1460,7 +1462,7 @@ static inline int __tcp_mtu_to_mss(struct sock *sk, int pmtu)
 	mss_now -= icsk->icsk_ext_hdr_len;
 
 	/* Then reserve room for full set of TCP options and 8 bytes of data */
-	mss_now = max(mss_now, sysctl_tcp_min_snd_mss);
+	mss_now = max(mss_now, sock_net(sk)->ipv4.sysctl_tcp_min_snd_mss);
 	return mss_now;
 }
 

net/ipv4/tcp_timer.c

@@ -166,7 +166,7 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
 		mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
 		mss = min(net->ipv4.sysctl_tcp_base_mss, mss);
 		mss = max(mss, 68 - tcp_sk(sk)->tcp_header_len);
-		mss = max(mss, sysctl_tcp_min_snd_mss);
+		mss = max(mss, net->ipv4.sysctl_tcp_min_snd_mss);
 		icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
 	}
 	tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);