Merge 4.4.182 into android-4.4

Changes in 4.4.182
	tcp: limit payload size of sacked skbs
	tcp: tcp_fragment() should apply sane memory limits
	tcp: add tcp_min_snd_mss sysctl
	tcp: enforce tcp_min_snd_mss in tcp_mtu_probing()
	Linux 4.4.182

Change-Id: I2698fa2ad3884a20d936e6bee638304f52df19bd
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 77a624e..a3cc4ee 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -220,6 +220,14 @@ tcp_base_mss - INTEGER
        Path MTU discovery (MTU probing).  If MTU probing is enabled,
        this is the initial MSS used by the connection.
 
+tcp_min_snd_mss - INTEGER
+       TCP SYN and SYNACK messages usually advertise an ADVMSS option,
+       as described in RFC 1122 and RFC 6691.
+       If this ADVMSS option is smaller than tcp_min_snd_mss,
+       it is silently capped to tcp_min_snd_mss.
+
+       Default : 48 (at least 8 bytes of payload per segment)
+
 tcp_congestion_control - STRING
        Set the congestion control algorithm to be used for new
        connections. The algorithm "reno" is always available, but

diff --git a/Makefile b/Makefile
index 61545ec..77811c2 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 VERSION = 4
 PATCHLEVEL = 4
-SUBLEVEL = 181
+SUBLEVEL = 182
 EXTRAVERSION =
 NAME = Blurry Fish Butt
 

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 747404d..085da17 100644 (file)
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -419,4 +419,7 @@ static inline void tcp_saved_syn_free(struct tcp_sock *tp)
        tp->saved_syn = NULL;
 }
 
+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
+                 int shiftlen);
+
 #endif /* _LINUX_TCP_H */

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index c68926b..61c38f8 100644 (file)
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -88,6 +88,7 @@ struct netns_ipv4 {
        int sysctl_tcp_fwmark_accept;
        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;
 

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 5bd9645..daf611b 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -54,6 +54,8 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
 
 #define MAX_TCP_HEADER (128 + MAX_HEADER)
 #define MAX_TCP_OPTION_SPACE 40
+#define TCP_MIN_SND_MSS                48
+#define TCP_MIN_GSO_SIZE       (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE)
 
 /*
  * Never offer a window over 32767 without using window scaling. Some

diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index 9de808e..422183f 100644 (file)
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -281,6 +281,7 @@ enum
        LINUX_MIB_TCPKEEPALIVE,                 /* TCPKeepAlive */
        LINUX_MIB_TCPMTUPFAIL,                  /* TCPMTUPFail */
        LINUX_MIB_TCPMTUPSUCCESS,               /* TCPMTUPSuccess */
+       LINUX_MIB_TCPWQUEUETOOBIG,              /* TCPWqueueTooBig */
        __LINUX_MIB_MAX
 };
 

diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index b001ad6..555586f 100644 (file)
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -303,6 +303,7 @@ static const struct snmp_mib snmp4_net_list[] = {
        SNMP_MIB_ITEM("TCPKeepAlive", LINUX_MIB_TCPKEEPALIVE),
        SNMP_MIB_ITEM("TCPMTUPFail", LINUX_MIB_TCPMTUPFAIL),
        SNMP_MIB_ITEM("TCPMTUPSuccess", LINUX_MIB_TCPMTUPSUCCESS),
+       SNMP_MIB_ITEM("TCPWqueueTooBig", LINUX_MIB_TCPWQUEUETOOBIG),
        SNMP_MIB_SENTINEL
 };
 

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index a48513b..a433886 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -36,6 +36,8 @@ static int ip_local_port_range_min[] = { 1, 1 };
 static int ip_local_port_range_max[] = { 65535, 65535 };
 static int tcp_adv_win_scale_min = -31;
 static int tcp_adv_win_scale_max = 31;
+static int tcp_min_snd_mss_min = TCP_MIN_SND_MSS;
+static int tcp_min_snd_mss_max = 65535;
 static int ip_ttl_min = 1;
 static int ip_ttl_max = 255;
 static int tcp_syn_retries_min = 1;
@@ -964,6 +966,15 @@ static struct ctl_table ipv4_net_table[] = {
                .proc_handler   = proc_dointvec,
        },
        {
+               .procname       = "tcp_min_snd_mss",
+               .data           = &init_net.ipv4.sysctl_tcp_min_snd_mss,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &tcp_min_snd_mss_min,
+               .extra2         = &tcp_min_snd_mss_max,
+       },
+       {
                .procname       = "tcp_probe_threshold",
                .data           = &init_net.ipv4.sysctl_tcp_probe_threshold,
                .maxlen         = sizeof(int),

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index e9f8443..d75fb0e 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3190,6 +3190,7 @@ void __init tcp_init(void)
        int max_rshare, max_wshare, cnt;
        unsigned int i;
 
+       BUILD_BUG_ON(TCP_MIN_SND_MSS <= MAX_TCP_OPTION_SPACE);
        sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
 
        percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a369344..705d629 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1276,7 +1276,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
        TCP_SKB_CB(skb)->seq += shifted;
 
        tcp_skb_pcount_add(prev, pcount);
-       BUG_ON(tcp_skb_pcount(skb) < pcount);
+       WARN_ON_ONCE(tcp_skb_pcount(skb) < pcount);
        tcp_skb_pcount_add(skb, -pcount);
 
        /* When we're adding to gso_segs == 1, gso_size will be zero,
@@ -1338,6 +1338,21 @@ static int skb_can_shift(const struct sk_buff *skb)
        return !skb_headlen(skb) && skb_is_nonlinear(skb);
 }
 
+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from,
+                 int pcount, int shiftlen)
+{
+       /* TCP min gso_size is 8 bytes (TCP_MIN_GSO_SIZE)
+        * Since TCP_SKB_CB(skb)->tcp_gso_segs is 16 bits, we need
+        * to make sure not storing more than 65535 * 8 bytes per skb,
+        * even if current MSS is bigger.
+        */
+       if (unlikely(to->len + shiftlen >= 65535 * TCP_MIN_GSO_SIZE))
+               return 0;
+       if (unlikely(tcp_skb_pcount(to) + pcount > 65535))
+               return 0;
+       return skb_shift(to, from, shiftlen);
+}
+
 /* Try collapsing SACK blocks spanning across multiple skbs to a single
  * skb.
  */
@@ -1349,6 +1364,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *prev;
        int mss;
+       int next_pcount;
        int pcount = 0;
        int len;
        int in_sack;
@@ -1443,7 +1459,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
        if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una))
                goto fallback;
 
-       if (!skb_shift(prev, skb, len))
+       if (!tcp_skb_shift(prev, skb, pcount, len))
                goto fallback;
        if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))
                goto out;
@@ -1462,11 +1478,11 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
                goto out;
 
        len = skb->len;
-       if (skb_shift(prev, skb, len)) {
-               pcount += tcp_skb_pcount(skb);
-               tcp_shifted_skb(sk, skb, state, tcp_skb_pcount(skb), len, mss, 0);
+       next_pcount = tcp_skb_pcount(skb);
+       if (tcp_skb_shift(prev, skb, next_pcount, len)) {
+               pcount += next_pcount;
+               tcp_shifted_skb(sk, skb, state, next_pcount, len, mss, 0);
        }
-
 out:
        state->fack_count += pcount;
        return prev;

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a32818f..29f398e 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2414,6 +2414,7 @@ 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;
 

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 9ada5e4..6f7303d 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1161,6 +1161,11 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
        if (nsize < 0)
                nsize = 0;
 
+       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;
 
@@ -1327,8 +1332,7 @@ 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 */
-       if (mss_now < 48)
-               mss_now = 48;
+       mss_now = max(mss_now, sock_net(sk)->ipv4.sysctl_tcp_min_snd_mss);
        return mss_now;
 }
 

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 35f638c..6135994 100644 (file)
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -132,6 +132,7 @@ 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 - tp->tcp_header_len);
+                       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);
                }